From ba36a38a6c4be38fe4e09cc95a40b58a48daed79 Mon Sep 17 00:00:00 2001
From: Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com>
Date: Fri, 8 Apr 2022 22:48:00 +0900
Subject: [PATCH] Allow empty dist name in bencode which is needed for hybrid
 torrent

---
 src/GenericParser.h                      |  9 +++++++--
 src/ValueBaseBencodeParser.h             |  2 +-
 src/ValueBaseStructParserStateMachine.cc |  5 +++++
 src/ValueBaseStructParserStateMachine.h  |  2 ++
 src/XmlRpcRequestParserController.cc     |  7 ++++++-
 src/XmlRpcRequestParserController.h      | 11 ++++++++++-
 test/ValueBaseBencodeParserTest.cc       | 10 ++++++++++
 7 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/src/GenericParser.h b/src/GenericParser.h
index 86c6ca92..7373b066 100644
--- a/src/GenericParser.h
+++ b/src/GenericParser.h
@@ -42,9 +42,14 @@
 
 namespace aria2 {
 
-template <typename Parser, typename ParserStateMachine> class GenericParser {
+template <typename Parser, typename ParserStateMachine,
+          bool allowEmptyName = false>
+class GenericParser {
 public:
-  GenericParser() : parser_{&psm_} {}
+  GenericParser() : parser_{&psm_}
+  {
+    psm_.setAllowEmptyMemberName(allowEmptyName);
+  }
 
   ~GenericParser() = default;
 
diff --git a/src/ValueBaseBencodeParser.h b/src/ValueBaseBencodeParser.h
index cfc43145..91cfc37b 100644
--- a/src/ValueBaseBencodeParser.h
+++ b/src/ValueBaseBencodeParser.h
@@ -43,7 +43,7 @@ namespace aria2 {
 
 namespace bittorrent {
 
-typedef GenericParser<BencodeParser, ValueBaseStructParserStateMachine>
+typedef GenericParser<BencodeParser, ValueBaseStructParserStateMachine, true>
     ValueBaseBencodeParser;
 
 } // namespace bittorrent
diff --git a/src/ValueBaseStructParserStateMachine.cc b/src/ValueBaseStructParserStateMachine.cc
index b026758a..caf6296e 100644
--- a/src/ValueBaseStructParserStateMachine.cc
+++ b/src/ValueBaseStructParserStateMachine.cc
@@ -213,4 +213,9 @@ void ValueBaseStructParserStateMachine::pushNullState()
   stateStack_.push(nullState);
 }
 
+void ValueBaseStructParserStateMachine::setAllowEmptyMemberName(bool b)
+{
+  ctrl_->setAllowEmptyMemberName(b);
+}
+
 } // namespace aria2
diff --git a/src/ValueBaseStructParserStateMachine.h b/src/ValueBaseStructParserStateMachine.h
index a049de3a..c309cfb6 100644
--- a/src/ValueBaseStructParserStateMachine.h
+++ b/src/ValueBaseStructParserStateMachine.h
@@ -106,6 +106,8 @@ public:
   void pushBoolState();
   void pushNullState();
 
+  void setAllowEmptyMemberName(bool b);
+
 private:
   std::unique_ptr<rpc::XmlRpcRequestParserController> ctrl_;
   std::stack<ValueBaseStructParserState*> stateStack_;
diff --git a/src/XmlRpcRequestParserController.cc b/src/XmlRpcRequestParserController.cc
index 25a5addc..a3c9a857 100644
--- a/src/XmlRpcRequestParserController.cc
+++ b/src/XmlRpcRequestParserController.cc
@@ -54,7 +54,7 @@ void XmlRpcRequestParserController::popStructFrame()
   Dict* dict = downcast<Dict>(parentFrame.value_);
   assert(dict);
   frameStack_.pop();
-  if (currentFrame_.validMember()) {
+  if (currentFrame_.validMember(allowEmptyMemberName_)) {
     dict->put(std::move(currentFrame_.name_), std::move(currentFrame_.value_));
   }
   currentFrame_ = std::move(parentFrame);
@@ -110,6 +110,11 @@ void XmlRpcRequestParserController::setMethodName(std::string methodName)
   methodName_ = std::move(methodName);
 }
 
+void XmlRpcRequestParserController::setAllowEmptyMemberName(bool b)
+{
+  allowEmptyMemberName_ = b;
+}
+
 } // namespace rpc
 
 } // namespace aria2
diff --git a/src/XmlRpcRequestParserController.h b/src/XmlRpcRequestParserController.h
index 7892147b..b84a7de1 100644
--- a/src/XmlRpcRequestParserController.h
+++ b/src/XmlRpcRequestParserController.h
@@ -52,7 +52,10 @@ private:
     std::unique_ptr<ValueBase> value_;
     std::string name_;
 
-    bool validMember() const { return value_ && !name_.empty(); }
+    bool validMember(bool allowEmptyMemberName) const
+    {
+      return value_ && (allowEmptyMemberName || !name_.empty());
+    }
 
     void reset()
     {
@@ -67,7 +70,11 @@ private:
 
   std::string methodName_;
 
+  bool allowEmptyMemberName_;
+
 public:
+  XmlRpcRequestParserController() : allowEmptyMemberName_(false) {}
+
   void pushFrame();
 
   // Pops StateFrame p from frameStack_ and set p[currentFrame_.name_]
@@ -90,6 +97,8 @@ public:
 
   const std::string& getMethodName() const { return methodName_; }
 
+  void setAllowEmptyMemberName(bool b);
+
   void reset();
 };
 
diff --git a/test/ValueBaseBencodeParserTest.cc b/test/ValueBaseBencodeParserTest.cc
index 30cca2f4..2e12ec49 100644
--- a/test/ValueBaseBencodeParserTest.cc
+++ b/test/ValueBaseBencodeParserTest.cc
@@ -208,6 +208,16 @@ void ValueBaseBencodeParserTest::testParseUpdate()
     // Get trailing garbage position
     CPPUNIT_ASSERT_EQUAL((ssize_t)7, error);
   }
+  {
+    // dict, empty member name
+    std::string src = "d0:i123ee";
+    std::shared_ptr<ValueBase> d =
+        parser.parseFinal(src.c_str(), src.size(), error);
+    Dict* dict = downcast<Dict>(d);
+    CPPUNIT_ASSERT(dict);
+    CPPUNIT_ASSERT(dict->get(""));
+    CPPUNIT_ASSERT_EQUAL((int64_t)123, downcast<Integer>(dict->get(""))->i());
+  }
 }
 
 } // namespace aria2