diff --git a/.gitignore b/.gitignore
index ac840d38..6fd65cc1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,7 @@
 *~
 *.o
+*.lo
+*.la
 *.ce
 *.cce
 *.he
@@ -31,3 +33,4 @@ libtool
 ltmain.sh
 po/aria2.pot
 po/remove-potcdate.sed
+src/libaria2.pc
diff --git a/configure.ac b/configure.ac
index 1b717e06..6d2dc235 100644
--- a/configure.ac
+++ b/configure.ac
@@ -6,6 +6,12 @@ LT_PREREQ([2.2.6])
 AC_INIT([aria2],[1.17.0],[t-tujikawa@users.sourceforge.net],[aria2],[http://aria2.sourceforge.net/])
 AC_USE_SYSTEM_EXTENSIONS
 LT_INIT()
+dnl See versioning rule:
+dnl  http://www.gnu.org/software/libtool/manual/html_node/Updating-version-info.html
+AC_SUBST(LT_CURRENT, 0)
+AC_SUBST(LT_REVISION, 0)
+AC_SUBST(LT_AGE, 0)
+
 AC_CONFIG_MACRO_DIR([m4])
 AC_CANONICAL_HOST
 AC_CANONICAL_TARGET
@@ -789,7 +795,8 @@ if test "x$enable_message_digest" = "xyes"; then
   enable_websocket=yes
   AC_DEFINE([ENABLE_WEBSOCKET], [1],
             [Define 1 if WebSocket support is enabled.])
-  LIBS="\$(top_builddir)/deps/wslay/lib/libwslay.la $LIBS"
+  WSLAY_LIBS="\$(top_builddir)/deps/wslay/lib/libwslay.la"
+  AC_SUBST([WSLAY_LIBS])
   # $(top_srcdir) for `make distcheck`
   CPPFLAGS="-I\$(top_builddir)/deps/wslay/lib/includes -I\$(top_srcdir)/deps/wslay/lib/includes $CPPFLAGS"
 fi
@@ -815,6 +822,8 @@ fi
 
 AC_CONFIG_FILES([Makefile
 		src/Makefile
+		src/libaria2.pc
+		src/includes/Makefile
 		test/Makefile
 		po/Makefile.in
 		intl/Makefile
diff --git a/deps/wslay/configure.ac b/deps/wslay/configure.ac
index 57fc931a..91f8f29c 100644
--- a/deps/wslay/configure.ac
+++ b/deps/wslay/configure.ac
@@ -23,7 +23,7 @@ dnl WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 AC_PREREQ(2.61)
 AC_INIT([wslay], [0.1.1], [t-tujikawa@users.sourceforge.net])
 LT_PREREQ([2.2.6])
-LT_INIT([disable-shared])
+LT_INIT()
 AC_CONFIG_AUX_DIR([.])
 dnl See versioning rule:
 dnl  http://www.gnu.org/software/libtool/manual/html_node/Updating-version-info.html
diff --git a/src/Context.cc b/src/Context.cc
new file mode 100644
index 00000000..ad6b1af1
--- /dev/null
+++ b/src/Context.cc
@@ -0,0 +1,294 @@
+/* <!-- copyright */
+/*
+ * aria2 - The high speed download utility
+ *
+ * Copyright (C) 2013 Tatsuhiro Tsujikawa
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link the code of portions of this program with the
+ * OpenSSL library under certain conditions as described in each
+ * individual source file, and distribute linked combinations
+ * including the two.
+ * You must obey the GNU General Public License in all respects
+ * for all of the code used other than OpenSSL.  If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so.  If you
+ * do not wish to do so, delete this exception statement from your
+ * version.  If you delete this exception statement from all source
+ * files in the program, then also delete it here.
+ */
+/* copyright --> */
+#include "Context.h"
+
+#include <unistd.h>
+#include <getopt.h>
+
+#include <numeric>
+#include <vector>
+#include <iostream>
+
+#include "SharedHandle.h"
+#include "LogFactory.h"
+#include "Logger.h"
+#include "util.h"
+#include "FeatureConfig.h"
+#include "MultiUrlRequestInfo.h"
+#include "SimpleRandomizer.h"
+#include "File.h"
+#include "message.h"
+#include "prefs.h"
+#include "Option.h"
+#include "a2algo.h"
+#include "a2io.h"
+#include "a2time.h"
+#include "Platform.h"
+#include "FileEntry.h"
+#include "RequestGroup.h"
+#include "ConsoleStatCalc.h"
+#include "NullStatCalc.h"
+#include "download_helper.h"
+#include "Exception.h"
+#include "ProtocolDetector.h"
+#include "RecoverableException.h"
+#include "SocketCore.h"
+#include "DownloadContext.h"
+#include "fmt.h"
+#include "NullOutputFile.h"
+#include "console.h"
+#include "UriListParser.h"
+#ifdef ENABLE_BITTORRENT
+# include "bittorrent_helper.h"
+#endif // ENABLE_BITTORRENT
+#ifdef ENABLE_METALINK
+# include "metalink_helper.h"
+# include "MetalinkEntry.h"
+#endif // ENABLE_METALINK
+#ifdef ENABLE_MESSAGE_DIGEST
+# include "message_digest_helper.h"
+#endif // ENABLE_MESSAGE_DIGEST
+
+extern char* optarg;
+extern int optind, opterr, optopt;
+
+namespace aria2 {
+
+SharedHandle<StatCalc> getStatCalc(const SharedHandle<Option>& op)
+{
+  SharedHandle<StatCalc> statCalc;
+  if(op->getAsBool(PREF_QUIET)) {
+    statCalc.reset(new NullStatCalc());
+  } else {
+    SharedHandle<ConsoleStatCalc> impl
+      (new ConsoleStatCalc(op->getAsInt(PREF_SUMMARY_INTERVAL),
+                           op->getAsBool(PREF_HUMAN_READABLE)));
+    impl->setReadoutVisibility(op->getAsBool(PREF_SHOW_CONSOLE_READOUT));
+    impl->setTruncate(op->getAsBool(PREF_TRUNCATE_CONSOLE_READOUT));
+    statCalc = impl;
+  }
+  return statCalc;
+}
+
+SharedHandle<OutputFile> getSummaryOut(const SharedHandle<Option>& op)
+{
+  if(op->getAsBool(PREF_QUIET)) {
+    return SharedHandle<OutputFile>(new NullOutputFile());
+  } else {
+    return global::cout();
+  }
+}
+
+#ifdef ENABLE_BITTORRENT
+namespace {
+void showTorrentFile(const std::string& uri)
+{
+  SharedHandle<Option> op(new Option());
+  SharedHandle<DownloadContext> dctx(new DownloadContext());
+  bittorrent::load(uri, dctx, op);
+  bittorrent::print(*global::cout(), dctx);
+}
+} // namespace
+#endif // ENABLE_BITTORRENT
+
+#ifdef ENABLE_METALINK
+namespace {
+void showMetalinkFile
+(const std::string& uri, const SharedHandle<Option>& op)
+{
+  std::vector<SharedHandle<MetalinkEntry> > metalinkEntries;
+  metalink::parseAndQuery(metalinkEntries, uri, op.get(),
+                          op->get(PREF_METALINK_BASE_URI));
+  std::vector<SharedHandle<FileEntry> > fileEntries;
+  MetalinkEntry::toFileEntry(fileEntries, metalinkEntries);
+  util::toStream(fileEntries.begin(), fileEntries.end(), *global::cout());
+  global::cout()->write("\n");
+  global::cout()->flush();
+}
+} // namespace
+#endif // ENABLE_METALINK
+
+#if defined ENABLE_BITTORRENT || defined ENABLE_METALINK
+namespace {
+void showFiles
+(const std::vector<std::string>& uris, const SharedHandle<Option>& op)
+{
+  ProtocolDetector dt;
+  for(std::vector<std::string>::const_iterator i = uris.begin(),
+        eoi = uris.end(); i != eoi; ++i) {
+    printf(">>> ");
+    printf(MSG_SHOW_FILES, (*i).c_str());
+    printf("\n");
+    try {
+#ifdef ENABLE_BITTORRENT
+      if(dt.guessTorrentFile(*i)) {
+        showTorrentFile(*i);
+      } else
+#endif // ENABLE_BITTORRENT
+#ifdef ENABLE_METALINK
+        if(dt.guessMetalinkFile(*i)) {
+          showMetalinkFile(*i, op);
+        } else
+#endif // ENABLE_METALINK
+          {
+            printf(MSG_NOT_TORRENT_METALINK);
+            printf("\n\n");
+          }
+    } catch(RecoverableException& e) {
+      global::cout()->printf("%s\n", e.stackTrace().c_str());
+    }
+  }
+}
+} // namespace
+#endif // ENABLE_BITTORRENT || ENABLE_METALINK
+
+extern error_code::Value option_processing(Option& option, bool standalone,
+                                           std::vector<std::string>& uris,
+                                           int argc, char** argv,
+                                           const KeyVals& options);
+
+Context::Context(bool standalone,
+                 int argc, char** argv, const KeyVals& options)
+{
+  std::vector<std::string> args;
+  SharedHandle<Option> op(new Option());
+  error_code::Value rv;
+  rv = option_processing(*op.get(), standalone, args, argc, argv, options);
+  if(rv != error_code::FINISHED) {
+    if(standalone) {
+      exit(rv);
+    } else {
+      throw DL_ABORT_EX("Option processing failed");
+    }
+  }
+  SimpleRandomizer::init();
+#ifdef ENABLE_BITTORRENT
+  bittorrent::generateStaticPeerId(op->get(PREF_PEER_ID_PREFIX));
+#endif // ENABLE_BITTORRENT
+  LogFactory::setLogFile(op->get(PREF_LOG));
+  LogFactory::setLogLevel(op->get(PREF_LOG_LEVEL));
+  LogFactory::setConsoleLogLevel(op->get(PREF_CONSOLE_LOG_LEVEL));
+  if(op->getAsBool(PREF_QUIET)) {
+    LogFactory::setConsoleOutput(false);
+  }
+  LogFactory::reconfigure();
+  A2_LOG_INFO("<<--- --- --- ---");
+  A2_LOG_INFO("  --- --- --- ---");
+  A2_LOG_INFO("  --- --- --- --->>");
+  A2_LOG_INFO(fmt("%s %s %s", PACKAGE, PACKAGE_VERSION, TARGET));
+  A2_LOG_INFO(MSG_LOGGING_STARTED);
+
+  if(op->getAsBool(PREF_DISABLE_IPV6)) {
+    SocketCore::setProtocolFamily(AF_INET);
+    // Get rid of AI_ADDRCONFIG. It causes name resolution error
+    // when none of network interface has IPv4 address.
+    setDefaultAIFlags(0);
+  }
+  net::checkAddrconfig();
+  // Bind interface
+  if(!op->get(PREF_INTERFACE).empty()) {
+    std::string iface = op->get(PREF_INTERFACE);
+    SocketCore::bindAddress(iface);
+  }
+  std::vector<SharedHandle<RequestGroup> > requestGroups;
+  SharedHandle<UriListParser> uriListParser;
+#ifdef ENABLE_BITTORRENT
+  if(!op->blank(PREF_TORRENT_FILE)) {
+    if(op->get(PREF_SHOW_FILES) == A2_V_TRUE) {
+      showTorrentFile(op->get(PREF_TORRENT_FILE));
+      return;
+    } else {
+      createRequestGroupForBitTorrent(requestGroups, op, args,
+                                      op->get(PREF_TORRENT_FILE));
+    }
+  }
+  else
+#endif // ENABLE_BITTORRENT
+#ifdef ENABLE_METALINK
+    if(!op->blank(PREF_METALINK_FILE)) {
+      if(op->get(PREF_SHOW_FILES) == A2_V_TRUE) {
+        showMetalinkFile(op->get(PREF_METALINK_FILE), op);
+        return;
+      } else {
+        createRequestGroupForMetalink(requestGroups, op);
+      }
+    }
+    else
+#endif // ENABLE_METALINK
+      if(!op->blank(PREF_INPUT_FILE)) {
+        if(op->getAsBool(PREF_DEFERRED_INPUT)) {
+          uriListParser = openUriListParser(op->get(PREF_INPUT_FILE));
+        } else {
+          createRequestGroupForUriList(requestGroups, op);
+        }
+#if defined ENABLE_BITTORRENT || defined ENABLE_METALINK
+      } else if(op->get(PREF_SHOW_FILES) == A2_V_TRUE) {
+        showFiles(args, op);
+        return;
+#endif // ENABLE_METALINK || ENABLE_METALINK
+      } else {
+        createRequestGroupForUri(requestGroups, op, args, false, false, true);
+      }
+
+  // Remove option values which is only valid for URIs specified in
+  // command-line. If they are left, because op is used as a template
+  // for new RequestGroup(such as created in RPC command), they causes
+  // unintentional effect.
+  for(SharedHandle<Option> i = op; i; i = i->getParent()) {
+    i->remove(PREF_OUT);
+    i->remove(PREF_FORCE_SEQUENTIAL);
+    i->remove(PREF_INPUT_FILE);
+    i->remove(PREF_INDEX_OUT);
+    i->remove(PREF_SELECT_FILE);
+    i->remove(PREF_PAUSE);
+    i->remove(PREF_CHECKSUM);
+    i->remove(PREF_GID);
+  }
+  if(standalone &&
+     !op->getAsBool(PREF_ENABLE_RPC) && requestGroups.empty() &&
+     !uriListParser) {
+    global::cout()->printf("%s\n", MSG_NO_FILES_TO_DOWNLOAD);
+  } else {
+    reqinfo.reset(new MultiUrlRequestInfo(requestGroups, op, getStatCalc(op),
+                                          getSummaryOut(op),
+                                          uriListParser));
+  }
+}
+
+Context::~Context()
+{
+}
+
+} // namespace aria2
diff --git a/src/Context.h b/src/Context.h
new file mode 100644
index 00000000..061c9969
--- /dev/null
+++ b/src/Context.h
@@ -0,0 +1,59 @@
+/* <!-- copyright */
+/*
+ * aria2 - The high speed download utility
+ *
+ * Copyright (C) 2013 Tatsuhiro Tsujikawa
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link the code of portions of this program with the
+ * OpenSSL library under certain conditions as described in each
+ * individual source file, and distribute linked combinations
+ * including the two.
+ * You must obey the GNU General Public License in all respects
+ * for all of the code used other than OpenSSL.  If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so.  If you
+ * do not wish to do so, delete this exception statement from your
+ * version.  If you delete this exception statement from all source
+ * files in the program, then also delete it here.
+ */
+/* copyright --> */
+#ifndef CONTEXT_H
+#define CONTEXT_H
+
+#include "common.h"
+#include <aria2/aria2.h>
+#include "SharedHandle.h"
+
+namespace aria2 {
+
+class MultiUrlRequestInfo;
+
+struct Context {
+  // Set the |standalone| false if the context is created via libaria2
+  // API. The |argc| and |argv| is expected to the command-line
+  // arguments, which will be passed to getopt_long(3) in the end.
+  // The |options| is the additional option values and is considered
+  // as a part of command-line arguments.
+  Context(bool standalone, int argc, char** argv, const KeyVals& options);
+  ~Context();
+  SharedHandle<MultiUrlRequestInfo> reqinfo;
+};
+
+} // namespace aria2
+
+#endif // CONTEXT_H
diff --git a/src/DownloadEngine.cc b/src/DownloadEngine.cc
index 05478fe8..c014eb80 100644
--- a/src/DownloadEngine.cc
+++ b/src/DownloadEngine.cc
@@ -86,8 +86,9 @@ volatile sig_atomic_t globalHaltRequested = 0;
 DownloadEngine::DownloadEngine(const SharedHandle<EventPoll>& eventPoll)
   : eventPoll_(eventPoll),
     haltRequested_(0),
-    noWait_(false),
+    noWait_(true),
     refreshInterval_(DEFAULT_REFRESH_INTERVAL),
+    lastRefresh_(0),
     cookieStorage_(new CookieStorage()),
 #ifdef ENABLE_BITTORRENT
     btRegistry_(new BtRegistry()),
@@ -139,29 +140,31 @@ void executeCommand(std::deque<Command*>& commands,
 }
 } // namespace
 
-void DownloadEngine::run()
+int DownloadEngine::run(bool oneshot)
 {
-  Timer cp;
-  cp.reset(0);
   while(!commands_.empty() || !routineCommands_.empty()) {
+    if(!commands_.empty()) {
+      waitData();
+    }
+    noWait_ = false;
     global::wallclock().reset();
     calculateStatistics();
-    if(cp.differenceInMillis(global::wallclock())+A2_DELTA_MILLIS >=
+    if(lastRefresh_.differenceInMillis(global::wallclock())+A2_DELTA_MILLIS >=
        refreshInterval_) {
       refreshInterval_ = DEFAULT_REFRESH_INTERVAL;
-      cp = global::wallclock();
+      lastRefresh_ = global::wallclock();
       executeCommand(commands_, Command::STATUS_ALL);
     } else {
       executeCommand(commands_, Command::STATUS_ACTIVE);
     }
     executeCommand(routineCommands_, Command::STATUS_ALL);
     afterEachIteration();
-    if(!commands_.empty()) {
-      waitData();
+    if(!noWait_ && oneshot) {
+      return 1;
     }
-    noWait_ = false;
   }
   onEndOfRun();
+  return 0;
 }
 
 void DownloadEngine::waitData()
diff --git a/src/DownloadEngine.h b/src/DownloadEngine.h
index d949bff6..ff14a93e 100644
--- a/src/DownloadEngine.h
+++ b/src/DownloadEngine.h
@@ -124,6 +124,7 @@ private:
 
   // Milliseconds
   int64_t refreshInterval_;
+  Timer lastRefresh_;
 
   std::deque<Command*> routineCommands_;
 
@@ -167,7 +168,11 @@ public:
 
   ~DownloadEngine();
 
-  void run();
+  // If oneshot is true, this function returns after one event polling
+  // and performing action for them. This function returns 1 when
+  // oneshot is true and there are still downloads to be
+  // processed. Otherwise, returns 0.
+  int run(bool oneshot=false);
 
   void cleanQueue();
 
diff --git a/src/FillRequestGroupCommand.cc b/src/FillRequestGroupCommand.cc
index 5942489c..414402f5 100644
--- a/src/FillRequestGroupCommand.cc
+++ b/src/FillRequestGroupCommand.cc
@@ -60,7 +60,7 @@ bool FillRequestGroupCommand::execute()
   if(e_->isHaltRequested()) {
     return true;
   }
-  SharedHandle<RequestGroupMan> rgman = e_->getRequestGroupMan();
+  const SharedHandle<RequestGroupMan>& rgman = e_->getRequestGroupMan();
   if(rgman->queueCheckRequested()) {
     while(rgman->queueCheckRequested()) {
       try {
diff --git a/src/KeepRunningCommand.cc b/src/KeepRunningCommand.cc
new file mode 100644
index 00000000..995f3027
--- /dev/null
+++ b/src/KeepRunningCommand.cc
@@ -0,0 +1,59 @@
+/* <!-- copyright */
+/*
+ * aria2 - The high speed download utility
+ *
+ * Copyright (C) 2013 Tatsuhiro Tsujikawa
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link the code of portions of this program with the
+ * OpenSSL library under certain conditions as described in each
+ * individual source file, and distribute linked combinations
+ * including the two.
+ * You must obey the GNU General Public License in all respects
+ * for all of the code used other than OpenSSL.  If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so.  If you
+ * do not wish to do so, delete this exception statement from your
+ * version.  If you delete this exception statement from all source
+ * files in the program, then also delete it here.
+ */
+/* copyright --> */
+#include "KeepRunningCommand.h"
+#include "DownloadEngine.h"
+#include "RequestGroupMan.h"
+
+namespace aria2 {
+
+KeepRunningCommand::KeepRunningCommand(cuid_t cuid, DownloadEngine* e)
+  : Command(cuid),
+    e_(e)
+{
+  setStatusRealtime();
+}
+
+KeepRunningCommand::~KeepRunningCommand() {}
+
+bool KeepRunningCommand::execute()
+{
+  if(e_->isHaltRequested()) {
+    return true;
+  }
+  e_->addCommand(this);
+  return false;
+}
+
+} // namespace aria2
diff --git a/src/KeepRunningCommand.h b/src/KeepRunningCommand.h
new file mode 100644
index 00000000..9be030cb
--- /dev/null
+++ b/src/KeepRunningCommand.h
@@ -0,0 +1,57 @@
+/* <!-- copyright */
+/*
+ * aria2 - The high speed download utility
+ *
+ * Copyright (C) 2013 Tatsuhiro Tsujikawa
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link the code of portions of this program with the
+ * OpenSSL library under certain conditions as described in each
+ * individual source file, and distribute linked combinations
+ * including the two.
+ * You must obey the GNU General Public License in all respects
+ * for all of the code used other than OpenSSL.  If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so.  If you
+ * do not wish to do so, delete this exception statement from your
+ * version.  If you delete this exception statement from all source
+ * files in the program, then also delete it here.
+ */
+/* copyright --> */
+#ifndef KEEP_RUNNING_COMMAND_H
+#define KEEP_RUNNING_COMMAND_H
+
+#include "Command.h"
+
+namespace aria2 {
+
+class DownloadEngine;
+
+// This object does nothing but it is added to DownloadEngine command
+// queue (not routine one), and keeps event polling work.
+class KeepRunningCommand : public Command {
+public:
+  KeepRunningCommand(cuid_t cuid, DownloadEngine* e);
+  virtual ~KeepRunningCommand();
+  virtual bool execute();
+private:
+  DownloadEngine* e_;
+};
+
+} // namespace aria2
+
+#endif // KEEP_RUNNING_COMMAND_H
diff --git a/src/Makefile.am b/src/Makefile.am
index 6333d73a..756c73cf 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,8 +1,10 @@
+SUBDIRS = includes
 bin_PROGRAMS = aria2c
-aria2c_SOURCES = main.cc\
-	option_processing.cc\
-	version_usage.cc
-SRCS =  SocketCore.cc SocketCore.h\
+aria2c_SOURCES = main.cc
+SRCS =  option_processing.cc\
+	version_usage.cc\
+	Context.cc Context.h\
+	SocketCore.cc SocketCore.h\
 	BinaryStream.h\
 	Command.cc Command.h\
 	AbstractCommand.cc AbstractCommand.h\
@@ -634,10 +636,20 @@ SRCS += LibuvEventPoll.cc LibuvEventPoll.h
 endif # HAVE_LIBUV
 
 AR = @AR@
-noinst_LIBRARIES = libaria2c.a
-libaria2c_a_SOURCES = $(SRCS)
-aria2c_LDADD = libaria2c.a @LIBINTL@ @ALLOCA@ #-lprofiler
+
+pkgconfigdir = $(libdir)/pkgconfig
+pkgconfig_DATA = libaria2.pc
+DISTCLEANFILES = $(pkgconfig_DATA)
+
+lib_LTLIBRARIES = libaria2.la
+libaria2_la_SOURCES = $(SRCS) \
+	aria2api.cc aria2api.h \
+	KeepRunningCommand.cc KeepRunningCommand.h
+libaria2_la_LIBADD = @WSLAY_LIBS@
+
+LDADD = libaria2.la @LIBINTL@ @ALLOCA@ #-lprofiler
 #aria2c_LDFLAGS = -pg
 AM_CPPFLAGS =  -Wall\
 	-I$(top_srcdir)/lib -I$(top_srcdir)/intl\
+	-I$(srcdir)/includes -I$(builddir)/includes\
 	-DLOCALEDIR=\"@localedir@\" -DCA_BUNDLE=\"$(ca_bundle)\" @DEFS@ #-pg
diff --git a/src/MultiUrlRequestInfo.cc b/src/MultiUrlRequestInfo.cc
index b0156aca..7d16e33e 100644
--- a/src/MultiUrlRequestInfo.cc
+++ b/src/MultiUrlRequestInfo.cc
@@ -109,12 +109,15 @@ MultiUrlRequestInfo::MultiUrlRequestInfo
  const SharedHandle<StatCalc>& statCalc,
  const SharedHandle<OutputFile>& summaryOut,
  const SharedHandle<UriListParser>& uriListParser)
-  : requestGroups_(requestGroups),
-    option_(op),
+  : option_(op),
     statCalc_(statCalc),
     summaryOut_(summaryOut),
-    uriListParser_(uriListParser)
-{}
+    uriListParser_(uriListParser),
+    // TODO init mask_
+    useSignalHandler_(true)
+{
+  requestGroups_.swap(requestGroups);
+}
 
 MultiUrlRequestInfo::~MultiUrlRequestInfo() {}
 
@@ -126,17 +129,15 @@ void MultiUrlRequestInfo::printMessageForContinue()
      _("If there are any errors, then see the log file. See '-l' option in help/man page for details."));
 }
 
-error_code::Value MultiUrlRequestInfo::execute()
+int MultiUrlRequestInfo::prepare()
 {
-  error_code::Value returnValue = error_code::FINISHED;
-  sigset_t mask;
   try {
     SharedHandle<rpc::WebSocketSessionMan> wsSessionMan;
     if(option_->getAsBool(PREF_ENABLE_RPC)) {
       wsSessionMan.reset(new rpc::WebSocketSessionMan());
     }
-    Notifier notifier(wsSessionMan);
-    SingletonHolder<Notifier>::instance(&notifier);
+    SharedHandle<Notifier> notifier(new Notifier(wsSessionMan));
+    SingletonHolder<Notifier>::instance(notifier);
 
 #ifdef ENABLE_SSL
     if(option_->getAsBool(PREF_ENABLE_RPC) &&
@@ -159,15 +160,16 @@ error_code::Value MultiUrlRequestInfo::execute()
     }
 #endif // ENABLE_SSL
 
-    SharedHandle<DownloadEngine> e =
-      DownloadEngineFactory().newDownloadEngine(option_.get(), requestGroups_);
+    e_ = DownloadEngineFactory().newDownloadEngine(option_.get(),
+                                                   requestGroups_);
     // Avoid keeping RequestGroups alive longer than necessary
     requestGroups_.clear();
 
     if(!option_->blank(PREF_LOAD_COOKIES)) {
       File cookieFile(option_->get(PREF_LOAD_COOKIES));
       if(cookieFile.isFile() &&
-         e->getCookieStorage()->load(cookieFile.getPath(), Time().getTime())) {
+         e_->getCookieStorage()->load(cookieFile.getPath(),
+                                      Time().getTime())) {
         A2_LOG_INFO(fmt("Loaded cookies from '%s'.",
                         cookieFile.getPath().c_str()));
       } else {
@@ -194,7 +196,7 @@ error_code::Value MultiUrlRequestInfo::execute()
         authConfigFactory->setNetrc(netrc);
       }
     }
-    e->setAuthConfigFactory(authConfigFactory);
+    e_->setAuthConfigFactory(authConfigFactory);
 
 #ifdef ENABLE_SSL
     SharedHandle<TLSContext> clTlsContext(TLSContext::make(TLS_CLIENT));
@@ -220,7 +222,7 @@ error_code::Value MultiUrlRequestInfo::execute()
 #ifdef HAVE_ARES_ADDR_NODE
     ares_addr_node* asyncDNSServers =
       parseAsyncDNSServers(option_->get(PREF_ASYNC_DNS_SERVER));
-    e->setAsyncDNSServers(asyncDNSServers);
+    e_->setAsyncDNSServers(asyncDNSServers);
 #endif // HAVE_ARES_ADDR_NODE
     if(!Timer::monotonicClock()) {
       A2_LOG_WARN("Don't change system time while aria2c is running."
@@ -229,86 +231,143 @@ error_code::Value MultiUrlRequestInfo::execute()
 
     std::string serverStatIf = option_->get(PREF_SERVER_STAT_IF);
     if(!serverStatIf.empty()) {
-      e->getRequestGroupMan()->loadServerStat(serverStatIf);
-      e->getRequestGroupMan()->removeStaleServerStat
+      e_->getRequestGroupMan()->loadServerStat(serverStatIf);
+      e_->getRequestGroupMan()->removeStaleServerStat
         (option_->getAsInt(PREF_SERVER_STAT_TIMEOUT));
     }
-    e->setStatCalc(statCalc_);
+    e_->setStatCalc(statCalc_);
     if(uriListParser_) {
-      e->getRequestGroupMan()->setUriListParser(uriListParser_);
+      e_->getRequestGroupMan()->setUriListParser(uriListParser_);
     }
-#ifdef HAVE_SIGACTION
-    sigemptyset(&mask);
-    sigaddset(&mask, SIGINT);
-    sigaddset(&mask, SIGTERM);
-#ifdef SIGHUP
-    sigaddset(&mask, SIGHUP);
-#endif // SIGHUP
-#else // !HAVE_SIGACTION
-    mask = 0;
-#endif // !HAVE_SIGACTION
-
-#ifdef SIGHUP
-    util::setGlobalSignalHandler(SIGHUP, &mask, handler, 0);
-#endif // SIGHUP
-    util::setGlobalSignalHandler(SIGINT, &mask, handler, 0);
-    util::setGlobalSignalHandler(SIGTERM, &mask, handler, 0);
-
-    e->getRequestGroupMan()->getNetStat().downloadStart();
-    e->run();
-
-    if(!option_->blank(PREF_SAVE_COOKIES)) {
-      e->getCookieStorage()->saveNsFormat(option_->get(PREF_SAVE_COOKIES));
-    }
-
-    const std::string& serverStatOf = option_->get(PREF_SERVER_STAT_OF);
-    if(!serverStatOf.empty()) {
-      e->getRequestGroupMan()->saveServerStat(serverStatOf);
-    }
-    e->getRequestGroupMan()->showDownloadResults
-      (*summaryOut_, option_->get(PREF_DOWNLOAD_RESULT) == A2_V_FULL);
-    summaryOut_->flush();
-
-    RequestGroupMan::DownloadStat s =
-      e->getRequestGroupMan()->getDownloadStat();
-    if(!s.allCompleted()) {
-      printMessageForContinue();
-      if(s.getLastErrorResult() == error_code::FINISHED &&
-         s.getInProgress() > 0) {
-        returnValue = error_code::IN_PROGRESS;
-      } else {
-        returnValue = s.getLastErrorResult();
-      }
-    }
-    SessionSerializer sessionSerializer(e->getRequestGroupMan());
-    // TODO Add option: --save-session-status=error,inprogress,waiting
-    if(!option_->blank(PREF_SAVE_SESSION)) {
-      const std::string& filename = option_->get(PREF_SAVE_SESSION);
-      if(sessionSerializer.save(filename)) {
-        A2_LOG_NOTICE(fmt(_("Serialized session to '%s' successfully."),
-                          filename.c_str()));
-      } else {
-        A2_LOG_NOTICE(fmt(_("Failed to serialize session to '%s'."),
-                          filename.c_str()));
-      }
+    if(useSignalHandler_) {
+      setupSignalHandlers();
     }
+    e_->getRequestGroupMan()->getNetStat().downloadStart();
   } catch(RecoverableException& e) {
-    if(returnValue == error_code::FINISHED) {
-      returnValue = error_code::UNKNOWN_ERROR;
+    SingletonHolder<Notifier>::clear();
+    if(useSignalHandler_) {
+      resetSignalHandlers();
     }
-    A2_LOG_ERROR_EX(EX_EXCEPTION_CAUGHT, e);
+    return -1;
   }
-  SingletonHolder<Notifier>::instance(0);
+  return 0;
+}
 
-#ifdef HAVE_SIGACTION
-  sigemptyset(&mask);
-#endif // HAVE_SIGACTION
-#ifdef SIGHUP
-  util::setGlobalSignalHandler(SIGHUP, &mask, SIG_DFL, 0);
-#endif // SIGHUP
-  util::setGlobalSignalHandler(SIGINT, &mask, SIG_DFL, 0);
-  util::setGlobalSignalHandler(SIGTERM, &mask, SIG_DFL, 0);
+error_code::Value MultiUrlRequestInfo::getResult()
+{
+  error_code::Value returnValue = error_code::FINISHED;
+  if(!option_->blank(PREF_SAVE_COOKIES)) {
+    e_->getCookieStorage()->saveNsFormat(option_->get(PREF_SAVE_COOKIES));
+  }
+
+  const std::string& serverStatOf = option_->get(PREF_SERVER_STAT_OF);
+  if(!serverStatOf.empty()) {
+    e_->getRequestGroupMan()->saveServerStat(serverStatOf);
+  }
+  e_->getRequestGroupMan()->showDownloadResults
+    (*summaryOut_, option_->get(PREF_DOWNLOAD_RESULT) == A2_V_FULL);
+  summaryOut_->flush();
+
+  RequestGroupMan::DownloadStat s =
+    e_->getRequestGroupMan()->getDownloadStat();
+  if(!s.allCompleted()) {
+    printMessageForContinue();
+    if(s.getLastErrorResult() == error_code::FINISHED &&
+       s.getInProgress() > 0) {
+      returnValue = error_code::IN_PROGRESS;
+    } else {
+      returnValue = s.getLastErrorResult();
+    }
+  }
+  SessionSerializer sessionSerializer(e_->getRequestGroupMan());
+  // TODO Add option: --save-session-status=error,inprogress,waiting
+  if(!option_->blank(PREF_SAVE_SESSION)) {
+    const std::string& filename = option_->get(PREF_SAVE_SESSION);
+    if(sessionSerializer.save(filename)) {
+      A2_LOG_NOTICE(fmt(_("Serialized session to '%s' successfully."),
+                        filename.c_str()));
+    } else {
+      A2_LOG_NOTICE(fmt(_("Failed to serialize session to '%s'."),
+                        filename.c_str()));
+    }
+  }
+  SingletonHolder<Notifier>::clear();
   return returnValue;
 }
 
+error_code::Value MultiUrlRequestInfo::execute()
+{
+  if(prepare() != 0) {
+    return error_code::UNKNOWN_ERROR;
+  }
+  // TODO Enclosed in try..catch block for just in case. Really need
+  // this?
+  try {
+    e_->run();
+  } catch(RecoverableException& e) {
+    A2_LOG_ERROR_EX(EX_EXCEPTION_CAUGHT, e);
+  }
+  error_code::Value returnValue = getResult();
+  if(useSignalHandler_) {
+    resetSignalHandlers();
+  }
+  return returnValue;
+}
+
+void MultiUrlRequestInfo::setupSignalHandlers()
+{
+#ifdef HAVE_SIGACTION
+    sigemptyset(&mask_);
+#else // !HAVE_SIGACTION
+    mask_ = 0;
+#endif // !HAVE_SIGACTION
+#ifdef SIGPIPE
+    util::setGlobalSignalHandler(SIGPIPE, &mask_, SIG_IGN, 0);
+#endif // SIGPIPE
+#ifdef SIGCHLD
+    // Avoid to create zombie process when forked child processes are
+    // died.
+    util::setGlobalSignalHandler(SIGCHLD, &mask_, SIG_IGN, 0);
+#endif // SIGCHILD
+
+#ifdef HAVE_SIGACTION
+    sigaddset(&mask_, SIGINT);
+    sigaddset(&mask_, SIGTERM);
+# ifdef SIGHUP
+    sigaddset(&mask_, SIGHUP);
+# endif // SIGHUP
+#endif // HAVE_SIGACTION
+
+#ifdef SIGHUP
+    util::setGlobalSignalHandler(SIGHUP, &mask_, handler, 0);
+#endif // SIGHUP
+    util::setGlobalSignalHandler(SIGINT, &mask_, handler, 0);
+    util::setGlobalSignalHandler(SIGTERM, &mask_, handler, 0);
+}
+
+void MultiUrlRequestInfo::resetSignalHandlers()
+{
+#ifdef HAVE_SIGACTION
+  sigemptyset(&mask_);
+#endif // HAVE_SIGACTION
+#ifdef SIGHUP
+  util::setGlobalSignalHandler(SIGHUP, &mask_, SIG_DFL, 0);
+#endif // SIGHUP
+  util::setGlobalSignalHandler(SIGINT, &mask_, SIG_DFL, 0);
+  util::setGlobalSignalHandler(SIGTERM, &mask_, SIG_DFL, 0);
+
+#ifdef SIGCHLD
+    util::setGlobalSignalHandler(SIGCHLD, &mask_, SIG_DFL, 0);
+#endif // SIGCHILD
+#ifdef SIGPIPE
+    util::setGlobalSignalHandler(SIGPIPE, &mask_, SIG_DFL, 0);
+#endif // SIGPIPE
+}
+
+const SharedHandle<DownloadEngine>&
+MultiUrlRequestInfo::getDownloadEngine() const
+{
+  return e_;
+}
+
 } // namespace aria2
diff --git a/src/MultiUrlRequestInfo.h b/src/MultiUrlRequestInfo.h
index 45a627df..6a324af0 100644
--- a/src/MultiUrlRequestInfo.h
+++ b/src/MultiUrlRequestInfo.h
@@ -37,10 +37,13 @@
 
 #include "common.h"
 
+#include <signal.h>
+
 #include <vector>
 
 #include "SharedHandle.h"
 #include "DownloadResult.h"
+#include "util.h"
 
 namespace aria2 {
 
@@ -49,10 +52,11 @@ class Option;
 class StatCalc;
 class OutputFile;
 class UriListParser;
+class DownloadEngine;
 
 class MultiUrlRequestInfo {
 private:
-  std::vector<SharedHandle<RequestGroup> >& requestGroups_;
+  std::vector<SharedHandle<RequestGroup> > requestGroups_;
 
   SharedHandle<Option> option_;
 
@@ -62,7 +66,15 @@ private:
 
   SharedHandle<UriListParser> uriListParser_;
 
+  SharedHandle<DownloadEngine> e_;
+
+  sigset_t mask_;
+
+  bool useSignalHandler_;
+
   void printMessageForContinue();
+  void setupSignalHandlers();
+  void resetSignalHandlers();
 public:
   /*
    * MultiRequestInfo effectively takes ownership of the
@@ -77,11 +89,31 @@ public:
 
   virtual ~MultiUrlRequestInfo();
 
-  /**
-   * Returns FINISHED if all downloads have completed, otherwise returns the
-   * last download result.
-   */
+  // Returns FINISHED if all downloads have completed, otherwise returns the
+  // last download result.
+  //
+  // This method actually calls prepare() and
+  // getDownloadEngine()->run(true) and getResult().
   error_code::Value execute();
+
+  // Performs preparations for downloads, including creating
+  // DownloadEngine instance. This function returns 0 if it succeeds,
+  // or -1.
+  int prepare();
+
+  // Performs finalization of download process, including saving
+  // sessions. This function returns last error code in this session,
+  // in particular, this function returns FINISHED if all downloads
+  // have completed.
+  error_code::Value getResult();
+
+  const SharedHandle<DownloadEngine>& getDownloadEngine() const;
+
+  // Signal handlers are not prepared if false is given.
+  void setUseSignalHandler(bool useSignalHandler)
+  {
+    useSignalHandler_ = useSignalHandler;
+  }
 };
 
 } // namespace aria2
diff --git a/src/NullOutputFile.h b/src/NullOutputFile.h
index ff14ef1b..97c05562 100644
--- a/src/NullOutputFile.h
+++ b/src/NullOutputFile.h
@@ -43,8 +43,8 @@ class NullOutputFile:public OutputFile {
 public:
   virtual ~NullOutputFile() {}
   virtual size_t write(const char* str) { return 0; }
-  virtual int vprintf(const char* format, va_list va) { return 0; }
   virtual int flush() { return 0; }
+  virtual int vprintf(const char* format, va_list va) { return 0; }
   virtual bool supportsColor() { return false; }
 };
 
diff --git a/src/OptionParser.cc b/src/OptionParser.cc
index 8aed0259..1cce8495 100644
--- a/src/OptionParser.cc
+++ b/src/OptionParser.cc
@@ -245,6 +245,20 @@ void OptionParser::parse(Option& option, std::istream& is) const
   }
 }
 
+void OptionParser::parse(Option& option, const KeyVals& options) const
+{
+  for(KeyVals::const_iterator i = options.begin(), eoi = options.end();
+      i != eoi; ++i) {
+    const Pref* pref = option::k2p((*i).first);
+    const OptionHandler* handler = find(pref);
+    if(handler) {
+      handler->parse(option, (*i).second);
+    } else {
+      A2_LOG_WARN(fmt("Unknown option: %s", (*i).first.c_str()));
+    }
+  }
+}
+
 void OptionParser::setOptionHandlers
 (const std::vector<OptionHandler*>& handlers)
 {
diff --git a/src/OptionParser.h b/src/OptionParser.h
index 2cd9f8e7..4f7d11a5 100644
--- a/src/OptionParser.h
+++ b/src/OptionParser.h
@@ -41,6 +41,7 @@
 #include <vector>
 #include <iosfwd>
 
+#include <aria2/aria2.h>
 #include "SharedHandle.h"
 
 namespace aria2 {
@@ -67,6 +68,8 @@ public:
 
   void parse(Option& option, std::istream& ios) const;
 
+  void parse(Option& option, const KeyVals& options) const;
+
   void parseDefaultValues(Option& option) const;
 
   void setOptionHandlers
diff --git a/src/RequestGroupMan.cc b/src/RequestGroupMan.cc
index d24e274f..54cfe5be 100644
--- a/src/RequestGroupMan.cc
+++ b/src/RequestGroupMan.cc
@@ -107,7 +107,7 @@ RequestGroupMan::RequestGroupMan
     (option->getAsInt(PREF_MAX_OVERALL_DOWNLOAD_LIMIT)),
     maxOverallUploadSpeedLimit_(option->getAsInt
                                 (PREF_MAX_OVERALL_UPLOAD_LIMIT)),
-    rpc_(option->getAsBool(PREF_ENABLE_RPC)),
+    keepRunning_(option->getAsBool(PREF_ENABLE_RPC)),
     queueCheck_(true),
     removedErrorResult_(0),
     removedLastErrorResult_(error_code::FINISHED),
@@ -125,7 +125,7 @@ RequestGroupMan::~RequestGroupMan()
 
 bool RequestGroupMan::downloadFinished()
 {
-  if(rpc_) {
+  if(keepRunning_) {
     return false;
   }
   return requestGroups_.empty() && reservedGroups_.empty();
@@ -214,9 +214,8 @@ void notifyDownloadEvent
 (const std::string& event, const SharedHandle<RequestGroup>& group)
 {
   // Check NULL to make unit test easier.
-  Notifier* notifier = SingletonHolder<Notifier>::instance();
-  if(notifier) {
-    notifier->notifyDownloadEvent(event, group);
+  if(SingletonHolder<Notifier>::instance()) {
+    SingletonHolder<Notifier>::instance()->notifyDownloadEvent(event, group);
   }
 }
 
@@ -475,7 +474,7 @@ void RequestGroupMan::fillRequestGroupFromReserver(DownloadEngine* e)
     }
     SharedHandle<RequestGroup> groupToAdd = *reservedGroups_.begin();
     reservedGroups_.pop_front();
-    if((rpc_ && groupToAdd->isPauseRequested()) ||
+    if((keepRunning_ && groupToAdd->isPauseRequested()) ||
        !groupToAdd->isDependencyResolved()) {
       pending.push_back(groupToAdd);
       continue;
diff --git a/src/RequestGroupMan.h b/src/RequestGroupMan.h
index 473941a3..186ed379 100644
--- a/src/RequestGroupMan.h
+++ b/src/RequestGroupMan.h
@@ -84,8 +84,9 @@ private:
 
   NetStat netStat_;
 
-  // true if JSON-RPC/XML-RPC is enabled.
-  bool rpc_;
+  // true if download engine should keep running even if there is no
+  // download to perform.
+  bool keepRunning_;
 
   bool queueCheck_;
 
@@ -335,6 +336,16 @@ public:
   // Initializes WrDiskCache according to PREF_DISK_CACHE option.  If
   // its value is 0, cache storage will not be initialized.
   void initWrDiskCache();
+
+  void setKeepRunning(bool flag)
+  {
+    keepRunning_ = flag;
+  }
+
+  bool getKeepRunning() const
+  {
+    return keepRunning_;
+  }
 };
 
 } // namespace aria2
diff --git a/src/RpcMethodImpl.cc b/src/RpcMethodImpl.cc
index 56b5bbcf..fa6d5a3b 100644
--- a/src/RpcMethodImpl.cc
+++ b/src/RpcMethodImpl.cc
@@ -421,32 +421,6 @@ SharedHandle<ValueBase> ForceRemoveRpcMethod::process
   return removeDownload(req, e, true);
 }
 
-namespace {
-bool pauseRequestGroup
-(const SharedHandle<RequestGroup>& group, bool reserved,  bool forcePause)
-{
-  if((reserved && !group->isPauseRequested()) ||
-     (!reserved &&
-      !group->isForceHaltRequested() &&
-      ((forcePause && group->isHaltRequested() && group->isPauseRequested()) ||
-       (!group->isHaltRequested() && !group->isPauseRequested())))) {
-    if(!reserved) {
-      // Call setHaltRequested before setPauseRequested because
-      // setHaltRequested calls setPauseRequested(false) internally.
-      if(forcePause) {
-        group->setForceHaltRequested(true, RequestGroup::NONE);
-      } else {
-        group->setHaltRequested(true, RequestGroup::NONE);
-      }
-    }
-    group->setPauseRequested(true);
-    return true;
-  } else {
-    return false;
-  }
-}
-} // namespace
-
 namespace {
 SharedHandle<ValueBase> pauseDownload
 (const RpcRequest& req, DownloadEngine* e, bool forcePause)
@@ -1546,4 +1520,28 @@ SharedHandle<ValueBase> NoSuchMethodRpcMethod::process
 
 } // namespace rpc
 
+bool pauseRequestGroup
+(const SharedHandle<RequestGroup>& group, bool reserved,  bool forcePause)
+{
+  if((reserved && !group->isPauseRequested()) ||
+     (!reserved &&
+      !group->isForceHaltRequested() &&
+      ((forcePause && group->isHaltRequested() && group->isPauseRequested()) ||
+       (!group->isHaltRequested() && !group->isPauseRequested())))) {
+    if(!reserved) {
+      // Call setHaltRequested before setPauseRequested because
+      // setHaltRequested calls setPauseRequested(false) internally.
+      if(forcePause) {
+        group->setForceHaltRequested(true, RequestGroup::NONE);
+      } else {
+        group->setHaltRequested(true, RequestGroup::NONE);
+      }
+    }
+    group->setPauseRequested(true);
+    return true;
+  } else {
+    return false;
+  }
+}
+
 } // namespace aria2
diff --git a/src/RpcMethodImpl.h b/src/RpcMethodImpl.h
index 00d64193..90e439c4 100644
--- a/src/RpcMethodImpl.h
+++ b/src/RpcMethodImpl.h
@@ -605,6 +605,9 @@ void gatherBitTorrentMetadata
 
 } // namespace rpc
 
+bool pauseRequestGroup
+(const SharedHandle<RequestGroup>& group, bool reserved,  bool forcePause);
+
 } // namespace aria2
 
 #endif // D_RPC_METHOD_IMPL_H
diff --git a/src/SingletonHolder.h b/src/SingletonHolder.h
index 7f8e2d69..dcfe9e33 100644
--- a/src/SingletonHolder.h
+++ b/src/SingletonHolder.h
@@ -35,30 +35,37 @@
 #ifndef D_SINGLETON_HOLDER_H
 #define D_SINGLETON_HOLDER_H
 
+#include "SharedHandle.h"
+
 namespace aria2 {
 
 template<typename T>
 class SingletonHolder {
 private:
-  static T* instance_;
+  static SharedHandle<T> instance_;
 
   SingletonHolder() {}
 public:
   ~SingletonHolder() {}
 
-  static T* instance()
+  static const SharedHandle<T>& instance()
   {
     return instance_;
   }
 
-  static void instance(T* instance)
+  static void instance(const SharedHandle<T>& instance)
   {
     instance_ = instance;
   }
+
+  static void clear()
+  {
+    instance_.reset();
+  }
 };
 
 template<typename T>
-T* SingletonHolder<T>::instance_ = 0;
+SharedHandle<T> SingletonHolder<T>::instance_;
 
 } // namespace aria2
 
diff --git a/src/aria2api.cc b/src/aria2api.cc
new file mode 100644
index 00000000..30f0b02e
--- /dev/null
+++ b/src/aria2api.cc
@@ -0,0 +1,637 @@
+/* <!-- copyright */
+/*
+ * aria2 - The high speed download utility
+ *
+ * Copyright (C) 2013 Tatsuhiro Tsujikawa
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link the code of portions of this program with the
+ * OpenSSL library under certain conditions as described in each
+ * individual source file, and distribute linked combinations
+ * including the two.
+ * You must obey the GNU General Public License in all respects
+ * for all of the code used other than OpenSSL.  If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so.  If you
+ * do not wish to do so, delete this exception statement from your
+ * version.  If you delete this exception statement from all source
+ * files in the program, then also delete it here.
+ */
+/* copyright --> */
+#include "aria2api.h"
+
+#include <functional>
+
+#include "Platform.h"
+#include "Context.h"
+#include "DownloadEngine.h"
+#include "OptionParser.h"
+#include "Option.h"
+#include "DlAbortEx.h"
+#include "fmt.h"
+#include "OptionHandler.h"
+#include "RequestGroupMan.h"
+#include "RequestGroup.h"
+#include "MultiUrlRequestInfo.h"
+#include "prefs.h"
+#include "download_helper.h"
+#include "LogFactory.h"
+#include "PieceStorage.h"
+#include "DownloadContext.h"
+#include "FileEntry.h"
+#include "BitfieldMan.h"
+#include "DownloadContext.h"
+#include "RpcMethodImpl.h"
+#include "console.h"
+#include "KeepRunningCommand.h"
+
+namespace aria2 {
+
+Session::Session(const KeyVals& options)
+  : context(new Context(false, 0, 0, options))
+{}
+
+Session::~Session()
+{}
+
+SessionConfig::SessionConfig()
+  : keepRunning(false),
+    useSignalHandler(true)
+{}
+
+namespace {
+Platform* platform = 0;
+} // namespace
+
+int libraryInit()
+{
+  global::initConsole(true);
+  try {
+    platform = new Platform();
+  } catch(RecoverableException& e) {
+    A2_LOG_ERROR_EX(EX_EXCEPTION_CAUGHT, e);
+    return -1;
+  }
+  LogFactory::setConsoleOutput(false);
+  return 0;
+}
+
+int libraryDeinit()
+{
+  delete platform;
+  return 0;
+}
+
+Session* sessionNew(const KeyVals& options, const SessionConfig& config)
+{
+  int rv;
+  Session* session;
+  try {
+    session = new Session(options);
+  } catch(RecoverableException& e) {
+    return 0;
+  }
+  if(session->context->reqinfo) {
+    if(!config.useSignalHandler) {
+      session->context->reqinfo->setUseSignalHandler(false);
+    }
+    rv = session->context->reqinfo->prepare();
+    if(rv != 0) {
+      delete session;
+      session = 0;
+    }
+    const SharedHandle<DownloadEngine>& e =
+      session->context->reqinfo->getDownloadEngine();
+    if(config.keepRunning) {
+      e->getRequestGroupMan()->setKeepRunning(true);
+      // Add command to make aria2 keep event polling
+      e->addCommand(new KeepRunningCommand(e->newCUID(), e.get()));
+    }
+  } else {
+    delete session;
+    session = 0;
+  }
+  return session;
+}
+
+int sessionFinal(Session* session)
+{
+  error_code::Value rv = session->context->reqinfo->getResult();
+  delete session;
+  return rv;
+}
+
+int run(Session* session, RUN_MODE mode)
+{
+  const SharedHandle<DownloadEngine>& e =
+    session->context->reqinfo->getDownloadEngine();
+  return e->run(mode == RUN_ONCE);
+}
+
+int shutdown(Session* session, bool force)
+{
+  const SharedHandle<DownloadEngine>& e =
+    session->context->reqinfo->getDownloadEngine();
+  if(force) {
+    e->requestForceHalt();
+  } else {
+    e->requestHalt();
+  }
+  // Skip next polling timeout. This avoids 1 second delay when there
+  // is no Command other than KeepRunningCommand in the queue.
+  e->setNoWait(true);
+  return 0;
+}
+
+std::string gidToHex(const A2Gid& gid)
+{
+  return GroupId::toHex(gid);
+}
+
+A2Gid hexToGid(const std::string& hex)
+{
+  A2Gid gid;
+  if(GroupId::toNumericId(gid, hex.c_str()) == 0) {
+    return gid;
+  } else {
+    return 0;
+  }
+}
+
+bool isNull(const A2Gid& gid)
+{
+  return gid == 0;
+}
+
+namespace {
+template<typename InputIterator, typename Pred>
+void apiGatherOption
+(InputIterator first, InputIterator last,
+ Pred pred,
+ Option* option,
+ const SharedHandle<OptionParser>& optionParser)
+{
+  for(; first != last; ++first) {
+    const std::string& optionName = (*first).first;
+    const Pref* pref = option::k2p(optionName);
+    if(!pref) {
+      throw DL_ABORT_EX
+        (fmt("We don't know how to deal with %s option", optionName.c_str()));
+    }
+    const OptionHandler* handler = optionParser->find(pref);
+    if(!handler || !pred(handler)) {
+      // Just ignore the unacceptable options in this context.
+      continue;
+    }
+    handler->parse(*option, (*first).second);
+  }
+}
+} // namespace
+
+namespace {
+void apiGatherRequestOption(Option* option, const KeyVals& options,
+                            const SharedHandle<OptionParser>& optionParser)
+{
+  apiGatherOption(options.begin(), options.end(),
+                  std::mem_fun(&OptionHandler::getInitialOption),
+                  option, optionParser);
+}
+} // namespace
+
+namespace {
+void addRequestGroup(const SharedHandle<RequestGroup>& group,
+                     const SharedHandle<DownloadEngine>& e,
+                     int position)
+{
+  if(position >= 0) {
+    e->getRequestGroupMan()->insertReservedGroup(position, group);
+  } else {
+    e->getRequestGroupMan()->addReservedGroup(group);
+  }
+}
+} // namespace
+
+int addUri(Session* session,
+           A2Gid& gid,
+           const std::vector<std::string>& uris,
+           const KeyVals& options,
+           int position)
+{
+  const SharedHandle<DownloadEngine>& e =
+    session->context->reqinfo->getDownloadEngine();
+  SharedHandle<Option> requestOption(new Option(*e->getOption()));
+  try {
+    apiGatherRequestOption(requestOption.get(), options,
+                           OptionParser::getInstance());
+  } catch(RecoverableException& e) {
+    A2_LOG_INFO_EX(EX_EXCEPTION_CAUGHT, e);
+    return -1;
+  }
+  std::vector<SharedHandle<RequestGroup> > result;
+  createRequestGroupForUri(result, requestOption, uris,
+                           /* ignoreForceSeq = */ true,
+                           /* ignoreLocalPath = */ true);
+  if(!result.empty()) {
+    gid = result.front()->getGID();
+    addRequestGroup(result.front(), e, position);
+  }
+  return 0;
+}
+
+int addMetalink(Session* session,
+                std::vector<A2Gid>& gids,
+                const std::string& metalinkFile,
+                const KeyVals& options,
+                int position)
+{
+#ifdef ENABLE_METALINK
+  const SharedHandle<DownloadEngine>& e =
+    session->context->reqinfo->getDownloadEngine();
+  SharedHandle<Option> requestOption(new Option(*e->getOption()));
+  std::vector<SharedHandle<RequestGroup> > result;
+  try {
+    apiGatherRequestOption(requestOption.get(), options,
+                           OptionParser::getInstance());
+    requestOption->put(PREF_METALINK_FILE, metalinkFile);
+    createRequestGroupForMetalink(result, requestOption);
+  } catch(RecoverableException& e) {
+    A2_LOG_INFO_EX(EX_EXCEPTION_CAUGHT, e);
+    return -1;
+  }
+  if(!result.empty()) {
+    if(position >= 0) {
+      e->getRequestGroupMan()->insertReservedGroup(position, result);
+    } else {
+      e->getRequestGroupMan()->addReservedGroup(result);
+    }
+    for(std::vector<SharedHandle<RequestGroup> >::const_iterator i =
+          result.begin(), eoi = result.end(); i != eoi; ++i) {
+      gids.push_back((*i)->getGID());
+    }
+  }
+  return 0;
+#else // !ENABLE_METALINK
+  return -1;
+#endif // !ENABLE_METALINK
+}
+
+int removeDownload(Session* session, const A2Gid& gid, bool force)
+{
+  const SharedHandle<DownloadEngine>& e =
+    session->context->reqinfo->getDownloadEngine();
+  SharedHandle<RequestGroup> group = e->getRequestGroupMan()->findGroup(gid);
+  if(group) {
+    if(group->getState() == RequestGroup::STATE_ACTIVE) {
+      if(force) {
+        group->setForceHaltRequested(true, RequestGroup::USER_REQUEST);
+      } else {
+        group->setHaltRequested(true, RequestGroup::USER_REQUEST);
+      }
+      e->setRefreshInterval(0);
+    } else {
+      if(group->isDependencyResolved()) {
+        e->getRequestGroupMan()->removeReservedGroup(gid);
+      } else {
+        return -1;
+      }
+    }
+  } else {
+    return -1;
+  }
+  return 0;
+}
+
+int pauseDownload(Session* session, const A2Gid& gid, bool force)
+{
+  const SharedHandle<DownloadEngine>& e =
+    session->context->reqinfo->getDownloadEngine();
+  SharedHandle<RequestGroup> group = e->getRequestGroupMan()->findGroup(gid);
+  if(group) {
+    bool reserved = group->getState() == RequestGroup::STATE_WAITING;
+    if(pauseRequestGroup(group, reserved, force)) {
+      e->setRefreshInterval(0);
+      return 0;
+    }
+  }
+  return -1;
+}
+
+int unpauseDownload(Session* session, const A2Gid& gid)
+{
+  const SharedHandle<DownloadEngine>& e =
+    session->context->reqinfo->getDownloadEngine();
+  SharedHandle<RequestGroup> group = e->getRequestGroupMan()->findGroup(gid);
+  if(!group ||
+     group->getState() != RequestGroup::STATE_WAITING ||
+     !group->isPauseRequested()) {
+    return -1;
+  } else {
+    group->setPauseRequested(false);
+    e->getRequestGroupMan()->requestQueueCheck();
+  }
+  return 0;
+}
+
+std::vector<A2Gid> getActiveDownload(Session* session)
+{
+  const SharedHandle<DownloadEngine>& e =
+    session->context->reqinfo->getDownloadEngine();
+  const RequestGroupList& groups = e->getRequestGroupMan()->getRequestGroups();
+  std::vector<A2Gid> res;
+  for(RequestGroupList::const_iterator i = groups.begin(),
+        eoi = groups.end(); i != eoi; ++i) {
+    res.push_back((*i)->getGID());
+  }
+  return res;
+}
+
+namespace {
+template<typename OutputIterator, typename InputIterator>
+void createUriEntry
+(OutputIterator out,
+ InputIterator first, InputIterator last,
+ UriStatus status)
+{
+  for(; first != last; ++first) {
+    UriData uriData;
+    uriData.uri = *first;
+    uriData.status = status;
+    out++ = uriData;
+  }
+}
+} // namespace
+
+namespace {
+template<typename OutputIterator>
+void createUriEntry
+(OutputIterator out, const SharedHandle<FileEntry>& file)
+{
+  createUriEntry(out,
+                 file->getSpentUris().begin(),
+                 file->getSpentUris().end(),
+                 URI_USED);
+  createUriEntry(out,
+                 file->getRemainingUris().begin(),
+                 file->getRemainingUris().end(),
+                 URI_WAITING);
+}
+} // namespace
+
+namespace {
+template<typename OutputIterator, typename InputIterator>
+void createFileEntry
+(OutputIterator out,
+ InputIterator first, InputIterator last,
+ const BitfieldMan* bf)
+{
+  size_t index = 1;
+  for(; first != last; ++first) {
+    FileData file;
+    file.index = index++;
+    file.path = (*first)->getPath();
+    file.length = (*first)->getLength();
+    file.completedLength = bf->getOffsetCompletedLength
+      ((*first)->getOffset(), (*first)->getLength());
+    file.selected = (*first)->isRequested();
+    createUriEntry(std::back_inserter(file.uris), *first);
+    out++ = file;
+  }
+}
+} // namespace
+
+namespace {
+template<typename OutputIterator, typename InputIterator>
+void createFileEntry
+(OutputIterator out,
+ InputIterator first, InputIterator last,
+ int64_t totalLength,
+ int32_t pieceLength,
+ const std::string& bitfield)
+{
+  BitfieldMan bf(pieceLength, totalLength);
+  bf.setBitfield(reinterpret_cast<const unsigned char*>(bitfield.data()),
+                 bitfield.size());
+  createFileEntry(out, first, last, &bf);
+}
+} // namespace
+
+namespace {
+template<typename OutputIterator, typename InputIterator>
+void createFileEntry
+(OutputIterator out,
+ InputIterator first, InputIterator last,
+ int64_t totalLength,
+ int32_t pieceLength,
+ const SharedHandle<PieceStorage>& ps)
+{
+  BitfieldMan bf(pieceLength, totalLength);
+  if(ps) {
+    bf.setBitfield(ps->getBitfield(), ps->getBitfieldLength());
+  }
+  createFileEntry(out, first, last, &bf);
+}
+} // namespace
+
+namespace {
+struct RequestGroupDH : public DownloadHandle {
+  RequestGroupDH(const SharedHandle<RequestGroup>& group)
+    : group(group),
+      ts(group->calculateStat())
+  {}
+  virtual ~RequestGroupDH() {}
+  virtual DownloadStatus getStatus()
+  {
+    if(group->getState() == RequestGroup::STATE_ACTIVE) {
+      return DOWNLOAD_ACTIVE;
+    } else {
+      if(group->isPauseRequested()) {
+        return DOWNLOAD_PAUSED;
+      } else {
+        return DOWNLOAD_WAITING;
+      }
+    }
+  }
+  virtual int64_t getTotalLength()
+  {
+    return group->getTotalLength();
+  }
+  virtual int64_t getCompletedLength()
+  {
+    return group->getCompletedLength();
+  }
+  virtual int64_t getUploadLength()
+  {
+    return ts.allTimeUploadLength;
+  }
+  virtual std::string getBitfield()
+  {
+    const SharedHandle<PieceStorage>& ps = group->getPieceStorage();
+    if(ps) {
+      return std::string(reinterpret_cast<const char*>(ps->getBitfield()),
+                         ps->getBitfieldLength());
+    } else {
+      return "";
+    }
+  }
+  virtual int getDownloadSpeed()
+  {
+    return ts.downloadSpeed;
+  }
+  virtual int getUploadSpeed()
+  {
+    return ts.uploadSpeed;
+  }
+  virtual size_t getNumPieces()
+  {
+    return group->getDownloadContext()->getNumPieces();
+  }
+  virtual int getConnections()
+  {
+    return group->getNumConnection();
+  }
+  virtual int getErrorCode()
+  {
+    return 0;
+  }
+  virtual const std::vector<A2Gid>& getFollowedBy()
+  {
+    return group->followedBy();
+  }
+  virtual A2Gid getBelongsTo()
+  {
+    return group->belongsTo();
+  }
+  virtual const std::string& getDir()
+  {
+    return group->getOption()->get(PREF_DIR);
+  }
+  virtual std::vector<FileData> getFiles()
+  {
+    std::vector<FileData> res;
+    const SharedHandle<DownloadContext>& dctx = group->getDownloadContext();
+    createFileEntry(std::back_inserter(res),
+                    dctx->getFileEntries().begin(),
+                    dctx->getFileEntries().end(),
+                    dctx->getTotalLength(), dctx->getPieceLength(),
+                    group->getPieceStorage());
+    return res;
+  }
+  SharedHandle<RequestGroup> group;
+  TransferStat ts;
+};
+} // namespace
+
+namespace {
+struct DownloadResultDH : public DownloadHandle {
+  DownloadResultDH(const SharedHandle<DownloadResult>& dr)
+    : dr(dr)
+  {}
+  virtual ~DownloadResultDH() {}
+  virtual DownloadStatus getStatus()
+  {
+    switch(dr->result) {
+    case error_code::FINISHED:
+      return DOWNLOAD_COMPLETE;
+    case error_code::REMOVED:
+      return DOWNLOAD_REMOVED;
+    default:
+      return DOWNLOAD_ERROR;
+    }
+  }
+  virtual int64_t getTotalLength()
+  {
+    return dr->totalLength;
+  }
+  virtual int64_t getCompletedLength()
+  {
+    return dr->completedLength;
+  }
+  virtual int64_t getUploadLength()
+  {
+    return dr->uploadLength;
+  }
+  virtual std::string getBitfield()
+  {
+    return dr->bitfield;
+  }
+  virtual int getDownloadSpeed()
+  {
+    return 0;
+  }
+  virtual int getUploadSpeed()
+  {
+    return 0;
+  }
+  virtual size_t getNumPieces()
+  {
+    return dr->numPieces;
+  }
+  virtual int getConnections()
+  {
+    return 0;
+  }
+  virtual int getErrorCode()
+  {
+    return dr->result;
+  }
+  virtual const std::vector<A2Gid>& getFollowedBy()
+  {
+    return dr->followedBy;
+  }
+  virtual A2Gid getBelongsTo()
+  {
+    return dr->belongsTo;
+  }
+  virtual const std::string& getDir()
+  {
+    return dr->dir;
+  }
+  virtual std::vector<FileData> getFiles()
+  {
+    std::vector<FileData> res;
+    createFileEntry(std::back_inserter(res),
+                    dr->fileEntries.begin(), dr->fileEntries.end(),
+                    dr->totalLength, dr->pieceLength, dr->bitfield);
+    return res;
+  }
+  SharedHandle<DownloadResult> dr;
+};
+} // namespace
+
+DownloadHandle* getDownloadHandle(Session* session, const A2Gid& gid)
+{
+  const SharedHandle<DownloadEngine>& e =
+    session->context->reqinfo->getDownloadEngine();
+  const SharedHandle<RequestGroupMan>& rgman = e->getRequestGroupMan();
+  SharedHandle<RequestGroup> group = rgman->findGroup(gid);
+  if(group) {
+    return new RequestGroupDH(group);
+  } else {
+    SharedHandle<DownloadResult> ds = rgman->findDownloadResult(gid);
+    if(ds) {
+      return new DownloadResultDH(ds);
+    }
+  }
+  return 0;
+}
+
+void deleteDownloadHandle(DownloadHandle* dh)
+{
+  delete dh;
+}
+
+} // namespace aria2
diff --git a/src/aria2api.h b/src/aria2api.h
new file mode 100644
index 00000000..29fe529e
--- /dev/null
+++ b/src/aria2api.h
@@ -0,0 +1,55 @@
+/* <!-- copyright */
+/*
+ * aria2 - The high speed download utility
+ *
+ * Copyright (C) 2013 Tatsuhiro Tsujikawa
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link the code of portions of this program with the
+ * OpenSSL library under certain conditions as described in each
+ * individual source file, and distribute linked combinations
+ * including the two.
+ * You must obey the GNU General Public License in all respects
+ * for all of the code used other than OpenSSL.  If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so.  If you
+ * do not wish to do so, delete this exception statement from your
+ * version.  If you delete this exception statement from all source
+ * files in the program, then also delete it here.
+ */
+/* copyright --> */
+#ifndef ARIA2_API_H
+#define ARIA2_API_H
+
+#include "common.h"
+
+#include <aria2/aria2.h>
+#include "SharedHandle.h"
+
+namespace aria2 {
+
+struct Context;
+
+struct Session {
+  Session(const KeyVals& options);
+  ~Session();
+  SharedHandle<Context> context;
+};
+
+} // namespace aria2
+
+#endif // ARIA2_API_H
diff --git a/src/console.cc b/src/console.cc
index cf0782a3..109c30ac 100644
--- a/src/console.cc
+++ b/src/console.cc
@@ -33,38 +33,47 @@
  */
 /* copyright --> */
 #include "console.h"
+#include "NullOutputFile.h"
+#ifdef __MINGW32__
+# include "WinConsoleFile.h"
+#else // !__MINGW32__
+# include "BufferedFile.h"
+#endif // !__MINGW32__
 
 namespace aria2 {
 
 namespace global {
 
-#ifdef __MINGW32__
-const SharedHandle<WinConsoleFile>& cout()
-{
-  static SharedHandle<WinConsoleFile> f(new WinConsoleFile(STD_OUTPUT_HANDLE));
-  return f;
-}
-#else // !__MINGW32__
-const SharedHandle<BufferedFile>& cout()
-{
-  static SharedHandle<BufferedFile> f(new BufferedFile(stdout));
-  return f;
-}
-#endif // !__MINGW32__
+namespace {
+Console consoleCout;
+Console consoleCerr;
+};
 
+void initConsole(bool suppress)
+{
+  if(suppress) {
+    consoleCerr.reset(new NullOutputFile());
+    consoleCout.reset(new NullOutputFile());
+  } else {
 #ifdef __MINGW32__
-const SharedHandle<WinConsoleFile>& cerr()
-{
-  static SharedHandle<WinConsoleFile> f(new WinConsoleFile(STD_ERROR_HANDLE));
-  return f;
-}
+    consoleCout.reset(new WinConsoleFile(STD_OUTPUT_HANDLE));
+    consoleCerr.reset(new WinConsoleFile(STD_ERROR_HANDLE));
 #else // !__MINGW32__
-const SharedHandle<BufferedFile>& cerr()
-{
-  static SharedHandle<BufferedFile> f(new BufferedFile(stderr));
-  return f;
-}
+    consoleCout.reset(new BufferedFile(stdout));
+    consoleCerr.reset(new BufferedFile(stderr));
 #endif // !__MINGW32__
+  }
+}
+
+const Console& cout()
+{
+  return consoleCout;
+}
+
+const Console& cerr()
+{
+  return consoleCerr;
+}
 
 } // namespace global
 
diff --git a/src/console.h b/src/console.h
index 3944b415..8b99f7f1 100644
--- a/src/console.h
+++ b/src/console.h
@@ -37,22 +37,18 @@
 
 #include "common.h"
 #include "SharedHandle.h"
-#ifdef __MINGW32__
-# include "WinConsoleFile.h"
-#else // !__MINGW32__
-# include "BufferedFile.h"
-#endif // !__MINGW32__
+#include "OutputFile.h"
 
 namespace aria2 {
 
-#ifdef __MINGW32__
-typedef SharedHandle<WinConsoleFile> Console;
-#else // !__MINGW32__
-typedef SharedHandle<BufferedFile> Console;
-#endif // !__MINGW32__
+typedef SharedHandle<OutputFile> Console;
 
 namespace global {
 
+// Initialize console output facility. If the |suppress| is true, all
+// output sent to the console objects are discarded.
+void initConsole(bool suppress);
+
 const Console& cout();
 const Console& cerr();
 
diff --git a/src/includes/Makefile.am b/src/includes/Makefile.am
new file mode 100644
index 00000000..d270bef8
--- /dev/null
+++ b/src/includes/Makefile.am
@@ -0,0 +1 @@
+nobase_include_HEADERS = aria2/aria2.h
diff --git a/src/includes/aria2/aria2.h b/src/includes/aria2/aria2.h
new file mode 100644
index 00000000..add04f47
--- /dev/null
+++ b/src/includes/aria2/aria2.h
@@ -0,0 +1,283 @@
+/* <!-- copyright */
+/*
+ * aria2 - The high speed download utility
+ *
+ * Copyright (C) 2013 Tatsuhiro Tsujikawa
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link the code of portions of this program with the
+ * OpenSSL library under certain conditions as described in each
+ * individual source file, and distribute linked combinations
+ * including the two.
+ * You must obey the GNU General Public License in all respects
+ * for all of the code used other than OpenSSL.  If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so.  If you
+ * do not wish to do so, delete this exception statement from your
+ * version.  If you delete this exception statement from all source
+ * files in the program, then also delete it here.
+ */
+/* copyright --> */
+#ifndef ARIA2_H
+#define ARIA2_H
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <string>
+#include <vector>
+
+// Libaria2: The aim of this library is provide same functionality
+// available in RPC methods. The function signatures are not
+// necessarily the same, because we can take advantage of the direct,
+// no latency, access to the aria2 core.
+//
+// Therefore, this library is not meant to be the fine-grained,
+// customizable, complete HTTP/FTP/BitTorrent library. If you are
+// looking for such library for HTTP/FTP access, consider libcurl.
+
+namespace aria2 {
+
+struct Session;
+
+// Initializes the global data. It also initializes
+// underlying libraries libaria2 depends on. This function returns 0
+// if it succeeds, or -1.
+//
+// Call this function only once before calling any other API functions.
+int libraryInit();
+
+// Releases the global data. This function returns 0 if
+// it succeeds, or -1.
+//
+// Call this function only once at the end of the application.
+int libraryDeinit();
+
+// type of GID
+typedef uint64_t A2Gid;
+
+// type of Key/Value pairs
+typedef std::vector<std::pair<std::string, std::string> > KeyVals;
+
+struct SessionConfig {
+  // The constructor fills default values for all members.
+  SessionConfig();
+  // If the |keepRunning| member is true, run(session, RUN_ONCE) will
+  // return 1 even if there are no download to perform. The behavior
+  // is very similar to RPC server, except that this option does not
+  // enable RPC functionality. To stop aria2, use shutdown() function.
+  // The default value is false.
+  bool keepRunning;
+  // If the |useSignalHandler| is true, the library setups following
+  // signal handlers in sessionNew(). These signal handlers are
+  // removed in sessionFinal(). The default value is true. If the
+  // application sets this member to false, it must handle these
+  // signals and ensure that run() is repeatedly called until it
+  // returns 0 and sessionFinal() is called after that. Failing these
+  // steps will lead to not saving .aria2 control file and no session
+  // serialization.
+  //
+  // SIGPIPE, SIGCHLD: ignored
+  // SIGHUP, SIGTERM: handled like shutdown(session, true) is called.
+  // SIGINT: handled like shutdown(session, false) is called.
+  bool useSignalHandler;
+};
+
+// Creates new Session object using the |options| as additional
+// parameters. The |options| is treated as if they are specified in
+// command-line to aria2c(1). This function returns the pointer to the
+// newly created Session object if it succeeds, or NULL.
+//
+// Please note that only one Session object can be created per
+// process.
+Session* sessionNew(const KeyVals& options, const SessionConfig& config);
+
+// Performs post-download action, including saving sessions etc and
+// destroys the |session| object, releasing the allocated resources
+// for it. This function returns the last error code and it is the
+// equivalent to the exit status of aria2c(1).
+int sessionFinal(Session* session);
+
+enum RUN_MODE {
+  RUN_DEFAULT,
+  RUN_ONCE
+};
+
+// Performs event polling and actions for them. If the |mode| is
+// RUN_DEFAULT, this function returns when no downloads are left to be
+// processed. In this case, this function returns 0.
+//
+// If the |mode| is RUN_ONCE, this function returns after one event
+// polling. In the current implementation, event polling timeouts in 1
+// second, so this function returns at most 1 second. On return, when
+// no downloads are left to be processed, this function returns
+// 0. Otherwise, returns 1, indicating that the caller must call this
+// function one or more time to complete downloads.
+int run(Session* session, RUN_MODE mode);
+
+// Returns textual representation of the |gid|.
+std::string gidToHex(const A2Gid& gid);
+// Returns GID converted from the textual representation |hex|.
+A2Gid hexToGid(const std::string& hex);
+// Returns true if the |gid| is invalid.
+bool isNull(const A2Gid& gid);
+
+// Adds new HTTP(S)/FTP/BitTorrent Magnet URI.  On successful return,
+// the |gid| includes the GID of newly added download.  The |uris|
+// includes URI to be downloaded.  For BitTorrent Magnet URI, the
+// |uris| must have only one element and it should be BitTorrent
+// Magnet URI. URIs in uris must point to the same file. If you mix
+// other URIs which point to another file, aria2 does not complain but
+// download may fail. The |options| is a pair of option name and
+// value. If the |position| is not negative integer, the new download
+// is inserted at position in the waiting queue. If the |position| is
+// negative or the |position| is larger than the size of the queue, it
+// is appended at the end of the queue.  This function returns 0 if it
+// succeeds, or -1.
+int addUri(Session* session,
+           A2Gid& gid,
+           const std::vector<std::string>& uris,
+           const KeyVals& options,
+           int position = -1);
+
+// Adds Metalink download. The path to Metalink file is specified by
+// the |metalinkFile|.  On successful return, the GID of added
+// download is appended to the |gids|. The |options| is a pair of
+// option name and value. If the |position| is not negative integer,
+// the new download is inserted at position in the waiting queue. If
+// the |position| is negative or the |position| is larger than the
+// size of the queue, it is appended at the end of the queue. This
+// function returns 0 if it succeeds, or -1.
+int addMetalink(Session* session,
+                std::vector<A2Gid>& gids,
+                const std::string& metalinkFile,
+                const KeyVals& options,
+                int position = -1);
+
+// Returns the array of active download GID.
+std::vector<A2Gid> getActiveDownload(Session* session);
+
+// Removes the download denoted by the |gid|. If the specified
+// download is in progress, it is stopped at first. The status of
+// removed download becomes DOWNLOAD_REMOVED. If the |force| is true,
+// removal will take place without any action which takes time such as
+// contacting BitTorrent tracker. This function returns 0 if it
+// succeeds, or -1.
+int removeDownload(Session* session, const A2Gid& gid, bool force = false);
+
+// Pauses the download denoted by the |gid|. The status of paused
+// download becomes DOWNLOAD_PAUSED. If the download is active, the
+// download is placed on the first position of waiting queue. As long
+// as the status is DOWNLOAD_PAUSED, the download will not start. To
+// change status to DOWNLOAD_WAITING, use unpauseDownload() function.
+// If the |force| is true, pause will take place without any action
+// which takes time such as contacting BitTorrent tracker. This
+// function returns 0 if it succeeds, or -1.  Please note that, to
+// make pause work, the application must call
+// sessionConfigSetKeepRunning() function with the |flag| argument to
+// true. Without this call, download may be paused at first, but it
+// will be restarted automatically.
+int pauseDownload(Session* session, const A2Gid& gid, bool force = false);
+
+// Changes the status of the download denoted by the |gid| from
+// DOWNLOAD_PAUSED to DOWNLOAD_WAITING. This makes the download
+// eligible to restart. This function returns 0 if it succeeds, or -1.
+int unpauseDownload(Session* session, const A2Gid& gid);
+
+// Schedules shutdown. If the |force| is true, shutdown will take
+// place without any action which takes time such as contacting
+// BitTorrent tracker. After this call, the application must keep
+// calling run() method until it returns 0.  This function returns 0
+// if it succeeds, or -1.
+int shutdown(Session* session, bool force = false);
+
+enum UriStatus {
+  URI_USED,
+  URI_WAITING
+};
+
+struct UriData {
+  std::string uri;
+  UriStatus status;
+};
+
+struct FileData {
+  int index;
+  std::string path;
+  int64_t length;
+  int64_t completedLength;
+  bool selected;
+  std::vector<UriData> uris;
+};
+
+enum DownloadStatus {
+  DOWNLOAD_ACTIVE,
+  DOWNLOAD_WAITING,
+  DOWNLOAD_PAUSED,
+  DOWNLOAD_COMPLETE,
+  DOWNLOAD_ERROR,
+  DOWNLOAD_REMOVED
+};
+
+struct DownloadHandle {
+  virtual ~DownloadHandle() {}
+  virtual DownloadStatus getStatus() = 0;
+  virtual int64_t getTotalLength() = 0;
+  virtual int64_t getCompletedLength() = 0;
+  virtual int64_t getUploadLength() = 0;
+  virtual std::string getBitfield() = 0;
+  virtual int getDownloadSpeed() = 0;
+  virtual int getUploadSpeed() = 0;
+  virtual size_t getNumPieces() = 0;
+  virtual int getConnections() = 0;
+  // Returns the last error code occurred in this download. The error
+  // codes are defined in EXIT STATUS section of aria2c(1) man
+  // page. This value is only available for stopped/completed
+  // downloads.
+  virtual int getErrorCode() = 0;
+  // Returns array of GIDs which are generated by the consequence of
+  // this download. For example, when aria2 downloaded Metalink file,
+  // it generates downloads described in it (see --follow-metalink
+  // option). This value is useful to track these auto generated
+  // downloads. If there is no such downloads, this function returns
+  // empty array.
+  virtual const std::vector<A2Gid>& getFollowedBy() = 0;
+  // Returns the GID of a parent download. Some downloads are a part
+  // of another download. For example, if a file in Metalink has
+  // BitTorrent resource, the download of ".torrent" is a part of that
+  // file. If this download has no parent, the invalid GID is returned
+  // (isNull(gid) is true).
+  virtual A2Gid getBelongsTo() = 0;
+  virtual const std::string& getDir() = 0;
+  virtual std::vector<FileData> getFiles() = 0;
+};
+
+// Returns handle for the download denoted by the |gid|. The caller
+// can retrieve various information of the download via returned
+// handle. The lifetime of the returned handle is before the next call
+// of run() or sessionFinal(). This function returns NULL if no
+// download denoted by the |gid| is present. The caller must call
+// deleteDownloadHandle() to delete the acquired handle.
+DownloadHandle* getDownloadHandle(Session* session, const A2Gid& gid);
+
+// Deallocates the |dh|. Calling this function with NULL is safe.
+void deleteDownloadHandle(DownloadHandle* dh);
+
+} // namespace aria2
+
+#endif // ARIA2_H
diff --git a/src/libaria2.pc.in b/src/libaria2.pc.in
new file mode 100644
index 00000000..dfb663ad
--- /dev/null
+++ b/src/libaria2.pc.in
@@ -0,0 +1,42 @@
+# aria2 - The high speed download utility
+#
+# Copyright (C) 2013 Tatsuhiro Tsujikawa
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+#
+# In addition, as a special exception, the copyright holders give
+# permission to link the code of portions of this program with the
+# OpenSSL library under certain conditions as described in each
+# individual source file, and distribute linked combinations
+# including the two.
+# You must obey the GNU General Public License in all respects
+# for all of the code used other than OpenSSL.  If you modify
+# file(s) with this exception, you may extend this exception to your
+# version of the file(s), but you are not obligated to do so.  If you
+# do not wish to do so, delete this exception statement from your
+# version.  If you delete this exception statement from all source
+# files in the program, then also delete it here.
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: aria2
+Description: High speed download utility library
+URL: http://aria2.sourceforge.net/
+Version: @VERSION@
+Libs: -L${libdir} -laria2
+# TODO Add Requires.private: here
+Cflags: -I${includedir}
diff --git a/src/main.cc b/src/main.cc
index c58300f3..3bb11889 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -34,270 +34,35 @@
 /* copyright --> */
 #include "common.h"
 
-#include <signal.h>
 #include <unistd.h>
-#include <getopt.h>
-
-#include <numeric>
-#include <vector>
-#include <iostream>
 
+#include <aria2/aria2.h>
 #include "SharedHandle.h"
-#include "LogFactory.h"
-#include "Logger.h"
-#include "util.h"
-#include "FeatureConfig.h"
+#include "Context.h"
 #include "MultiUrlRequestInfo.h"
-#include "SimpleRandomizer.h"
-#include "File.h"
 #include "message.h"
-#include "prefs.h"
-#include "Option.h"
-#include "a2algo.h"
-#include "a2io.h"
-#include "a2time.h"
 #include "Platform.h"
-#include "FileEntry.h"
-#include "RequestGroup.h"
-#include "ConsoleStatCalc.h"
-#include "NullStatCalc.h"
-#include "download_helper.h"
 #include "Exception.h"
-#include "ProtocolDetector.h"
-#include "RecoverableException.h"
-#include "SocketCore.h"
-#include "DownloadContext.h"
-#include "fmt.h"
-#include "NullOutputFile.h"
 #include "console.h"
-#include "UriListParser.h"
-#ifdef ENABLE_BITTORRENT
-# include "bittorrent_helper.h"
-#endif // ENABLE_BITTORRENT
-#ifdef ENABLE_METALINK
-# include "metalink_helper.h"
-# include "MetalinkEntry.h"
-#endif // ENABLE_METALINK
-#ifdef ENABLE_MESSAGE_DIGEST
-# include "message_digest_helper.h"
-#endif // ENABLE_MESSAGE_DIGEST
-
-extern char* optarg;
-extern int optind, opterr, optopt;
 
 namespace aria2 {
 
-SharedHandle<StatCalc> getStatCalc(const SharedHandle<Option>& op)
+error_code::Value main(int argc, char** argv)
 {
-  SharedHandle<StatCalc> statCalc;
-  if(op->getAsBool(PREF_QUIET)) {
-    statCalc.reset(new NullStatCalc());
-  } else {
-    SharedHandle<ConsoleStatCalc> impl
-      (new ConsoleStatCalc(op->getAsInt(PREF_SUMMARY_INTERVAL),
-                           op->getAsBool(PREF_HUMAN_READABLE)));
-    impl->setReadoutVisibility(op->getAsBool(PREF_SHOW_CONSOLE_READOUT));
-    impl->setTruncate(op->getAsBool(PREF_TRUNCATE_CONSOLE_READOUT));
-    statCalc = impl;
-  }
-  return statCalc;
-}
-
-SharedHandle<OutputFile> getSummaryOut(const SharedHandle<Option>& op)
-{
-  if(op->getAsBool(PREF_QUIET)) {
-    return SharedHandle<OutputFile>(new NullOutputFile());
-  } else {
-    return global::cout();
-  }
-}
-
-#ifdef ENABLE_BITTORRENT
-namespace {
-void showTorrentFile(const std::string& uri)
-{
-  SharedHandle<Option> op(new Option());
-  SharedHandle<DownloadContext> dctx(new DownloadContext());
-  bittorrent::load(uri, dctx, op);
-  bittorrent::print(*global::cout(), dctx);
-}
-} // namespace
-#endif // ENABLE_BITTORRENT
-
-#ifdef ENABLE_METALINK
-namespace {
-void showMetalinkFile
-(const std::string& uri, const SharedHandle<Option>& op)
-{
-  std::vector<SharedHandle<MetalinkEntry> > metalinkEntries;
-  metalink::parseAndQuery(metalinkEntries, uri, op.get(),
-                          op->get(PREF_METALINK_BASE_URI));
-  std::vector<SharedHandle<FileEntry> > fileEntries;
-  MetalinkEntry::toFileEntry(fileEntries, metalinkEntries);
-  util::toStream(fileEntries.begin(), fileEntries.end(), *global::cout());
-  global::cout()->write("\n");
-  global::cout()->flush();
-}
-} // namespace
-#endif // ENABLE_METALINK
-
-#if defined ENABLE_BITTORRENT || defined ENABLE_METALINK
-namespace {
-void showFiles
-(const std::vector<std::string>& uris, const SharedHandle<Option>& op)
-{
-  ProtocolDetector dt;
-  for(std::vector<std::string>::const_iterator i = uris.begin(),
-        eoi = uris.end(); i != eoi; ++i) {
-    printf(">>> ");
-    printf(MSG_SHOW_FILES, (*i).c_str());
-    printf("\n");
-    try {
-#ifdef ENABLE_BITTORRENT
-      if(dt.guessTorrentFile(*i)) {
-        showTorrentFile(*i);
-      } else
-#endif // ENABLE_BITTORRENT
-#ifdef ENABLE_METALINK
-        if(dt.guessMetalinkFile(*i)) {
-          showMetalinkFile(*i, op);
-        } else
-#endif // ENABLE_METALINK
-          {
-            printf(MSG_NOT_TORRENT_METALINK);
-            printf("\n\n");
-          }
-    } catch(RecoverableException& e) {
-      global::cout()->printf("%s\n", e.stackTrace().c_str());
-    }
-  }
-}
-} // namespace
-#endif // ENABLE_BITTORRENT || ENABLE_METALINK
-
-extern void option_processing(Option& option, std::vector<std::string>& uris,
-                              int argc, char* argv[]);
-
-error_code::Value main(int argc, char* argv[])
-{
-  std::vector<std::string> args;
-  SharedHandle<Option> op(new Option());
-  option_processing(*op.get(), args, argc, argv);
-
-  SimpleRandomizer::init();
-#ifdef ENABLE_BITTORRENT
-  bittorrent::generateStaticPeerId(op->get(PREF_PEER_ID_PREFIX));
-#endif // ENABLE_BITTORRENT
-  LogFactory::setLogFile(op->get(PREF_LOG));
-  LogFactory::setLogLevel(op->get(PREF_LOG_LEVEL));
-  LogFactory::setConsoleLogLevel(op->get(PREF_CONSOLE_LOG_LEVEL));
-  if(op->getAsBool(PREF_QUIET)) {
-    LogFactory::setConsoleOutput(false);
-  }
-  LogFactory::reconfigure();
+  Context context(true, argc, argv, KeyVals());
   error_code::Value exitStatus = error_code::FINISHED;
-  A2_LOG_INFO("<<--- --- --- ---");
-  A2_LOG_INFO("  --- --- --- ---");
-  A2_LOG_INFO("  --- --- --- --->>");
-  A2_LOG_INFO(fmt("%s %s %s", PACKAGE, PACKAGE_VERSION, TARGET));
-  A2_LOG_INFO(MSG_LOGGING_STARTED);
-
-  if(op->getAsBool(PREF_DISABLE_IPV6)) {
-    SocketCore::setProtocolFamily(AF_INET);
-    // Get rid of AI_ADDRCONFIG. It causes name resolution error
-    // when none of network interface has IPv4 address.
-    setDefaultAIFlags(0);
-  }
-  net::checkAddrconfig();
-  // Bind interface
-  if(!op->get(PREF_INTERFACE).empty()) {
-    std::string iface = op->get(PREF_INTERFACE);
-    SocketCore::bindAddress(iface);
-  }
-  sigset_t mask;
-#ifdef HAVE_SIGACTION
-  sigemptyset(&mask);
-#else // !HAVE_SIGACTION
-  mask = 0;
-#endif // !HAVE_SIGACTION
-#ifdef SIGPIPE
-  util::setGlobalSignalHandler(SIGPIPE, &mask, SIG_IGN, 0);
-#endif
-#ifdef SIGCHLD
-  // Avoid to create zombie process when forked child processes are
-  // died.
-  util::setGlobalSignalHandler(SIGCHLD, &mask, SIG_IGN, 0);
-#endif // SIGCHILD
-  std::vector<SharedHandle<RequestGroup> > requestGroups;
-  SharedHandle<UriListParser> uriListParser;
-#ifdef ENABLE_BITTORRENT
-  if(!op->blank(PREF_TORRENT_FILE)) {
-    if(op->get(PREF_SHOW_FILES) == A2_V_TRUE) {
-      showTorrentFile(op->get(PREF_TORRENT_FILE));
-      return exitStatus;
-    } else {
-      createRequestGroupForBitTorrent(requestGroups, op, args,
-                                      op->get(PREF_TORRENT_FILE));
-    }
-  }
-  else
-#endif // ENABLE_BITTORRENT
-#ifdef ENABLE_METALINK
-    if(!op->blank(PREF_METALINK_FILE)) {
-      if(op->get(PREF_SHOW_FILES) == A2_V_TRUE) {
-        showMetalinkFile(op->get(PREF_METALINK_FILE), op);
-        return exitStatus;
-      } else {
-        createRequestGroupForMetalink(requestGroups, op);
-      }
-    }
-    else
-#endif // ENABLE_METALINK
-      if(!op->blank(PREF_INPUT_FILE)) {
-        if(op->getAsBool(PREF_DEFERRED_INPUT)) {
-          uriListParser = openUriListParser(op->get(PREF_INPUT_FILE));
-        } else {
-          createRequestGroupForUriList(requestGroups, op);
-        }
-#if defined ENABLE_BITTORRENT || defined ENABLE_METALINK
-      } else if(op->get(PREF_SHOW_FILES) == A2_V_TRUE) {
-        showFiles(args, op);
-        return exitStatus;
-#endif // ENABLE_METALINK || ENABLE_METALINK
-      } else {
-        createRequestGroupForUri(requestGroups, op, args, false, false, true);
-      }
-
-  // Remove option values which is only valid for URIs specified in
-  // command-line. If they are left, because op is used as a template
-  // for new RequestGroup(such as created in RPC command), they causes
-  // unintentional effect.
-  for(SharedHandle<Option> i = op; i; i = i->getParent()) {
-    i->remove(PREF_OUT);
-    i->remove(PREF_FORCE_SEQUENTIAL);
-    i->remove(PREF_INPUT_FILE);
-    i->remove(PREF_INDEX_OUT);
-    i->remove(PREF_SELECT_FILE);
-    i->remove(PREF_PAUSE);
-    i->remove(PREF_CHECKSUM);
-    i->remove(PREF_GID);
-  }
-  if(!op->getAsBool(PREF_ENABLE_RPC) && requestGroups.empty() &&
-     !uriListParser) {
-    global::cout()->printf("%s\n", MSG_NO_FILES_TO_DOWNLOAD);
-  } else {
-    exitStatus = MultiUrlRequestInfo(requestGroups, op, getStatCalc(op),
-                                     getSummaryOut(op),
-                                     uriListParser).execute();
+  if(context.reqinfo) {
+    exitStatus = context.reqinfo->execute();
   }
   return exitStatus;
 }
 
 } // namespace aria2
 
-int main(int argc, char* argv[])
+int main(int argc, char** argv)
 {
   aria2::error_code::Value r;
+  aria2::global::initConsole(false);
   try {
     aria2::Platform platform;
     r = aria2::main(argc, argv);
diff --git a/src/option_processing.cc b/src/option_processing.cc
index 98ea844f..d93dff02 100644
--- a/src/option_processing.cc
+++ b/src/option_processing.cc
@@ -38,6 +38,7 @@
 #include <cstring>
 #include <sstream>
 
+#include <aria2/aria2.h>
 #include "Option.h"
 #include "prefs.h"
 #include "OptionParser.h"
@@ -189,8 +190,10 @@ void optionNativeToUtf8(Option& op)
 } // namespace
 #endif // __MINGW32__
 
-void option_processing(Option& op, std::vector<std::string>& uris,
-                       int argc, char* argv[])
+error_code::Value option_processing(Option& op, bool standalone,
+                                    std::vector<std::string>& uris,
+                                    int argc, char** argv,
+                                    const KeyVals& options)
 {
   const SharedHandle<OptionParser>& oparser = OptionParser::getInstance();
   try {
@@ -204,27 +207,28 @@ void option_processing(Option& op, std::vector<std::string>& uris,
       oparser->parse(op, cmdstream);
       noConf = op.getAsBool(PREF_NO_CONF);
       ucfname = op.get(PREF_CONF_PATH);
-
-      if(op.defined(PREF_VERSION)) {
-        showVersion();
-        exit(error_code::FINISHED);
-      }
-      if(op.defined(PREF_HELP)) {
-        std::string keyword;
-        if(op.get(PREF_HELP).empty()) {
-          keyword = strHelpTag(TAG_BASIC);
-        } else {
-          keyword = op.get(PREF_HELP);
-          if(util::startsWith(keyword, "--")) {
-            keyword.erase(keyword.begin(), keyword.begin()+2);
-          }
-          std::string::size_type eqpos = keyword.find("=");
-          if(eqpos != std::string::npos) {
-            keyword.erase(keyword.begin()+eqpos, keyword.end());
-          }
+      if(standalone) {
+        if(op.defined(PREF_VERSION)) {
+          showVersion();
+          exit(error_code::FINISHED);
+        }
+        if(op.defined(PREF_HELP)) {
+          std::string keyword;
+          if(op.get(PREF_HELP).empty()) {
+            keyword = strHelpTag(TAG_BASIC);
+          } else {
+            keyword = op.get(PREF_HELP);
+            if(util::startsWith(keyword, "--")) {
+              keyword.erase(keyword.begin(), keyword.begin()+2);
+            }
+            std::string::size_type eqpos = keyword.find("=");
+            if(eqpos != std::string::npos) {
+              keyword.erase(keyword.begin()+eqpos, keyword.end());
+            }
+          }
+          showUsage(keyword, oparser, global::cout());
+          exit(error_code::FINISHED);
         }
-        showUsage(keyword, oparser, global::cout());
-        exit(error_code::FINISHED);
       }
     }
     SharedHandle<Option> confOption(new Option());
@@ -252,18 +256,18 @@ void option_processing(Option& op, std::vector<std::string>& uris,
             global::cerr()->printf(_("Usage:"));
             global::cerr()->printf("\n%s\n", h->getDescription());
           }
-          exit(e.getErrorCode());
+          return e.getErrorCode();
         } catch(Exception& e) {
           global::cerr()->printf(_("Parse error in %s"), cfname.c_str());
           global::cerr()->printf("\n%s", e.stackTrace().c_str());
-          exit(e.getErrorCode());
+          return e.getErrorCode();
         }
       } else if(!ucfname.empty()) {
         global::cerr()->printf(_("Configuration file %s is not found."),
                                cfname.c_str());
         global::cerr()->printf("\n");
         showUsage(strHelpTag(TAG_HELP), oparser, global::cerr());
-        exit(error_code::UNKNOWN_ERROR);
+        return error_code::UNKNOWN_ERROR;
       }
     }
     // Override configuration with environment variables.
@@ -272,6 +276,12 @@ void option_processing(Option& op, std::vector<std::string>& uris,
     overrideWithEnv(*confOption, oparser, PREF_FTP_PROXY, "ftp_proxy");
     overrideWithEnv(*confOption, oparser, PREF_ALL_PROXY, "all_proxy");
     overrideWithEnv(*confOption, oparser, PREF_NO_PROXY, "no_proxy");
+    if(!standalone) {
+      // For non-standalone mode, set PREF_QUIET to true to suppress
+      // output. The caller can override this by including PREF_QUIET
+      // in options argument.
+      confOption->put(PREF_QUIET, A2_V_TRUE);
+    }
 
     // we must clear eof bit and seek to the beginning of the buffer.
     cmdstream.clear();
@@ -279,6 +289,7 @@ void option_processing(Option& op, std::vector<std::string>& uris,
     // finaly let's parse and store command-iine options.
     op.setParent(confOption);
     oparser->parse(op, cmdstream);
+    oparser->parse(op, options);
 #ifdef __MINGW32__
     optionNativeToUtf8(op);
     optionNativeToUtf8(*confOption);
@@ -291,17 +302,18 @@ void option_processing(Option& op, std::vector<std::string>& uris,
       global::cerr()->printf("\n");
       write(global::cerr(), *h);
     }
-    exit(e.getErrorCode());
+    return e.getErrorCode();
   } catch(UnknownOptionException& e) {
     showUsage("", oparser, global::cerr());
     showCandidates(e.getUnknownOption(), oparser);
-    exit(e.getErrorCode());
+    return e.getErrorCode();
   } catch(Exception& e) {
     global::cerr()->printf("%s", e.stackTrace().c_str());
     showUsage("", oparser, global::cerr());
-    exit(e.getErrorCode());
+    return e.getErrorCode();
   }
-  if(!op.getAsBool(PREF_ENABLE_RPC) &&
+  if(standalone &&
+     !op.getAsBool(PREF_ENABLE_RPC) &&
 #ifdef ENABLE_BITTORRENT
      op.blank(PREF_TORRENT_FILE) &&
 #endif // ENABLE_BITTORRENT
@@ -313,15 +325,16 @@ void option_processing(Option& op, std::vector<std::string>& uris,
       global::cerr()->printf(MSG_URI_REQUIRED);
       global::cerr()->printf("\n");
       showUsage("", oparser, global::cerr());
-      exit(error_code::UNKNOWN_ERROR);
+      return error_code::UNKNOWN_ERROR;
     }
   }
-  if(op.getAsBool(PREF_DAEMON)) {
+  if(standalone && op.getAsBool(PREF_DAEMON)) {
     if(daemon(0, 0) < 0) {
       perror(MSG_DAEMON_FAILED);
-      exit(error_code::UNKNOWN_ERROR);
+      return error_code::UNKNOWN_ERROR;
     }
   }
+  return error_code::FINISHED;
 }
 
 } // namespace aria2
diff --git a/test/AllTest.cc b/test/AllTest.cc
index de51085c..e0cf13db 100644
--- a/test/AllTest.cc
+++ b/test/AllTest.cc
@@ -9,8 +9,10 @@
 #include "Platform.h"
 #include "SocketCore.h"
 #include "util.h"
+#include "console.h"
 
 int main(int argc, char* argv[]) {
+  aria2::global::initConsole(false);
   aria2::Platform platform;
 
 #ifdef ENABLE_NLS
diff --git a/test/Makefile.am b/test/Makefile.am
index f91cde44..2ba15b50 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -237,9 +237,10 @@ if !HAVE_TIMEGM
 aria2c_SOURCES += TimegmTest.cc
 endif # !HAVE_TIMEGM
 
-aria2c_LDADD = ../src/libaria2c.a @LIBINTL@ @CPPUNIT_LIBS@
+aria2c_LDADD = ../src/libaria2.la @LIBINTL@ @CPPUNIT_LIBS@
 AM_CPPFLAGS =  -Wall\
 	-I$(top_srcdir)/src\
+	-I$(top_srcdir)/src/includes -I$(top_builddir)/src/includes\
 	-I$(top_srcdir)/lib -I$(top_srcdir)/intl\
         -DLOCALEDIR=\"$(localedir)\"\
 	-DA2_TEST_DIR=\"$(top_srcdir)/test\"\
diff --git a/test/OptionParserTest.cc b/test/OptionParserTest.cc
index db100102..31aaf93c 100644
--- a/test/OptionParserTest.cc
+++ b/test/OptionParserTest.cc
@@ -27,6 +27,7 @@ class OptionParserTest:public CppUnit::TestFixture {
   CPPUNIT_TEST(testParseDefaultValues);
   CPPUNIT_TEST(testParseArg);
   CPPUNIT_TEST(testParse);
+  CPPUNIT_TEST(testParseKeyVals);
   CPPUNIT_TEST_SUITE_END();
 private:
   SharedHandle<OptionParser> oparser_;
@@ -73,6 +74,7 @@ public:
   void testParseDefaultValues();
   void testParseArg();
   void testParse();
+  void testParseKeyVals();
 };
 
 
@@ -195,4 +197,16 @@ void OptionParserTest::testParse()
   CPPUNIT_ASSERT_EQUAL(std::string("World"), option.get(PREF_DIR));
 }
 
+void OptionParserTest::testParseKeyVals()
+{
+  Option option;
+  KeyVals kv;
+  kv.push_back(std::make_pair("timeout", "Hello"));
+  kv.push_back(std::make_pair("UNKNOWN", "x"));
+  kv.push_back(std::make_pair("dir", "World"));
+  oparser_->parse(option, kv);
+  CPPUNIT_ASSERT_EQUAL(std::string("Hello"), option.get(PREF_TIMEOUT));
+  CPPUNIT_ASSERT_EQUAL(std::string("World"), option.get(PREF_DIR));
+}
+
 } // namespace aria2
diff --git a/test/SingletonHolderTest.cc b/test/SingletonHolderTest.cc
index cb62bf4d..a3ac2eed 100644
--- a/test/SingletonHolderTest.cc
+++ b/test/SingletonHolderTest.cc
@@ -40,8 +40,8 @@ public:
 
 void SingletonHolderTest::testInstance()
 {
-  M m("Hello world.");
-  SingletonHolder<M>::instance(&m);
+  SharedHandle<M> m(new M("Hello world."));
+  SingletonHolder<M>::instance(m);
   CPPUNIT_ASSERT_EQUAL(std::string("Hello world."),
                        SingletonHolder<M>::instance()->greeting());