diff --git a/ChangeLog b/ChangeLog
index 9e9fe223..e675e251 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2008-08-24  Tatsuhiro Tsujikawa  <tujikawa at rednoah dot com>
+
+	Save temporary file first and rename to the destination on success.
+	Added test cases.
+	* src/RequestGroupMan.cc
+	* test/RequestGroupManTest.cc
+
 2008-08-23  Tatsuhiro Tsujikawa  <tujikawa at rednoah dot com>
 
 	Fixed the bug that the number of connected peer is exceeding the limit
diff --git a/src/RequestGroupMan.cc b/src/RequestGroupMan.cc
index a795192b..9cc4ce72 100644
--- a/src/RequestGroupMan.cc
+++ b/src/RequestGroupMan.cc
@@ -51,6 +51,7 @@
 #include "InOrderURISelector.h"
 #include "Option.h"
 #include "prefs.h"
+#include "File.h"
 #include <iomanip>
 #include <sstream>
 #include <ostream>
@@ -498,13 +499,14 @@ bool RequestGroupMan::loadServerStat(const std::string& filename)
 
 bool RequestGroupMan::saveServerStat(const std::string& filename) const
 {
-  std::ofstream out(filename.c_str());
+  std::string tempfile = filename+"__temp";
+  std::ofstream out(tempfile.c_str());
   if(!out) {
     _logger->error("Failed to open ServerStat file %s for write.",
-		   filename.c_str());
+		   tempfile.c_str());
     return false;
   }
-  if(_serverStatMan->save(out)) {
+  if(_serverStatMan->save(out) && File(tempfile).renameTo(filename)) {
     _logger->notice("ServerStat file %s saved successfully.", filename.c_str());
     return true;
   } else {
diff --git a/test/RequestGroupManTest.cc b/test/RequestGroupManTest.cc
index 8d08f34b..99197334 100644
--- a/test/RequestGroupManTest.cc
+++ b/test/RequestGroupManTest.cc
@@ -7,6 +7,9 @@
 #include "DownloadResult.h"
 #include "FileEntry.h"
 #include "ServerStatMan.h"
+#include "ServerStat.h"
+#include "File.h"
+#include <fstream>
 #include <cppunit/extensions/HelperMacros.h>
 
 namespace aria2 {
@@ -16,6 +19,8 @@ class RequestGroupManTest : public CppUnit::TestFixture {
   CPPUNIT_TEST_SUITE(RequestGroupManTest);
   CPPUNIT_TEST(testIsSameFileBeingDownloaded);
   CPPUNIT_TEST(testGetInitialCommands);
+  CPPUNIT_TEST(testLoadServerStat);
+  CPPUNIT_TEST(testSaveServerStat);
   CPPUNIT_TEST_SUITE_END();
 private:
 
@@ -28,6 +33,8 @@ public:
 
   void testIsSameFileBeingDownloaded();
   void testGetInitialCommands();
+  void testLoadServerStat();
+  void testSaveServerStat();
 };
 
 
@@ -69,4 +76,39 @@ void RequestGroupManTest::testGetInitialCommands()
   // TODO implement later
 }
 
+void RequestGroupManTest::testSaveServerStat()
+{
+  Option option;
+  RequestGroupMan rm(std::deque<SharedHandle<RequestGroup> >(), 0, &option);
+  SharedHandle<ServerStat> ss_localhost(new ServerStat("localhost", "http"));
+  rm.addServerStat(ss_localhost);
+  File f("/tmp/aria2_RequestGroupManTest_testSaveServerStat");
+  if(f.exists()) {
+    f.remove();
+  }
+  CPPUNIT_ASSERT(rm.saveServerStat(f.getPath()));
+  CPPUNIT_ASSERT(f.isFile());
+
+  f.remove();
+  CPPUNIT_ASSERT(f.mkdirs());
+  CPPUNIT_ASSERT(!rm.saveServerStat(f.getPath()));
+}
+
+void RequestGroupManTest::testLoadServerStat()
+{
+  File f("/tmp/aria2_RequestGroupManTest_testLoadServerStat");
+  std::ofstream o(f.getPath().c_str());
+  o << "host=localhost, protocol=http, dl_speed=0, last_updated=1219505257,"
+    << "status=OK";
+  o.close();
+
+  Option option;
+  RequestGroupMan rm(std::deque<SharedHandle<RequestGroup> >(), 0, &option);
+  CPPUNIT_ASSERT(rm.loadServerStat(f.getPath()));
+  SharedHandle<ServerStat> ss_localhost = rm.findServerStat("localhost",
+							    "http");
+  CPPUNIT_ASSERT(!ss_localhost.isNull());
+  CPPUNIT_ASSERT_EQUAL(std::string("localhost"), ss_localhost->getHostname());
+}
+
 } // namespace aria2