Simplified parse tree listener handling.

No need to use shared_ptr for management. Listeners are, like the other main classes (parser, lexer, input stream etc.) provided by the application and hence managed there.

doc/cpp-target.md

@@ -72,7 +72,7 @@ int main(int argc, const char* argv[]) {
  
 This example assumes your grammar contains a parser rule named `key` for which the enterKey function was generated. The `Ref<>` template is an alias for `std::shared_ptr<>` to simplify the runtime source code which often makes use of smart pointers.
 
-### Specialities of this ANTLR target
+## Specialities of this ANTLR target
 
 There are a couple of things that only the C++ ANTLR target has to deal with. They are described here.
 

runtime-testsuite/resources/org/antlr/v4/test/runtime/cpp/Cpp.test.stg

@@ -305,7 +305,7 @@ BasicListener(X) ::= <<
 @parser::definitions {
 class LeafListener : public TBaseListener {
 public:
-  virtual void visitTerminal(Ref\<tree::TerminalNode> const& node) override {
+  virtual void visitTerminal(tree::TerminalNode *node) override {
   std::cout \<\< node->getSymbol()->getText() \<\< std::endl;
   }
 };

runtime-testsuite/test/org/antlr/v4/test/runtime/cpp/TestListeners.java

@@ -13,13 +13,13 @@ public class TestListeners extends BaseCppTest {
 	public void testBasic() throws Exception {
 		mkdir(tmpdir);
 
-		StringBuilder grammarBuilder = new StringBuilder(491);
+		StringBuilder grammarBuilder = new StringBuilder(480);
 		grammarBuilder.append("grammar T;\n");
 		grammarBuilder.append("\n");
 		grammarBuilder.append("@parser::definitions {\n");
 		grammarBuilder.append("class LeafListener : public TBaseListener {\n");
 		grammarBuilder.append("public:\n");
-		grammarBuilder.append("  virtual void visitTerminal(Ref<tree::TerminalNode> const& node) override {\n");
+		grammarBuilder.append("  virtual void visitTerminal(tree::TerminalNode *node) override {\n");
 		grammarBuilder.append("  std::cout << node->getSymbol()->getText() << std::endl;\n");
 		grammarBuilder.append("  }\n");
 		grammarBuilder.append("};\n");

runtime/Cpp/runtime/antlrcpp.xcodeproj/project.pbxproj

@@ -1083,7 +1083,7 @@
 		276E5CD11CDB57AA003FF4B4 /* Predicate.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = Predicate.h; sourceTree = "<group>"; };
 		276E5CD41CDB57AA003FF4B4 /* NoViableAltException.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = NoViableAltException.cpp; sourceTree = "<group>"; wrapsLines = 0; };
 		276E5CD51CDB57AA003FF4B4 /* NoViableAltException.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = NoViableAltException.h; sourceTree = "<group>"; wrapsLines = 0; };
-		276E5CD61CDB57AA003FF4B4 /* Parser.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = Parser.cpp; sourceTree = "<group>"; };
+		276E5CD61CDB57AA003FF4B4 /* Parser.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = Parser.cpp; sourceTree = "<group>"; wrapsLines = 0; };
 		276E5CD71CDB57AA003FF4B4 /* Parser.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = Parser.h; sourceTree = "<group>"; };
 		276E5CD81CDB57AA003FF4B4 /* ParserInterpreter.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = ParserInterpreter.cpp; sourceTree = "<group>"; wrapsLines = 0; };
 		276E5CD91CDB57AA003FF4B4 /* ParserInterpreter.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ParserInterpreter.h; sourceTree = "<group>"; wrapsLines = 0; };

runtime/Cpp/runtime/src/Parser.cpp

@@ -77,8 +77,7 @@ void Parser::TraceListener::exitEveryRule(ParserRuleContext *ctx) {
     << ", LT(1)=" << outerInstance->_input->LT(1)->getText() << std::endl;
 }
 
-const Ref<Parser::TrimToSizeListener> Parser::TrimToSizeListener::INSTANCE =
-  std::make_shared<Parser::TrimToSizeListener>();
+Parser::TrimToSizeListener Parser::TrimToSizeListener::INSTANCE;
 
 void Parser::TrimToSizeListener::enterEveryRule(ParserRuleContext * /*ctx*/) {
 }
@@ -99,6 +98,7 @@ Parser::Parser(TokenStream *input) {
 }
 
 Parser::~Parser() {
+  delete _tracer;
 }
 
 void Parser::reset() {
@@ -166,21 +166,21 @@ void Parser::setTrimParseTree(bool trimParseTrees) {
     if (getTrimParseTree()) {
       return;
     }
-    addParseListener(TrimToSizeListener::INSTANCE);
+    addParseListener(&TrimToSizeListener::INSTANCE);
   } else {
-    removeParseListener(TrimToSizeListener::INSTANCE);
+    removeParseListener(&TrimToSizeListener::INSTANCE);
   }
 }
 
 bool Parser::getTrimParseTree() {
-  return std::find(getParseListeners().begin(), getParseListeners().end(), TrimToSizeListener::INSTANCE) != getParseListeners().end();
+  return std::find(getParseListeners().begin(), getParseListeners().end(), &TrimToSizeListener::INSTANCE) != getParseListeners().end();
 }
 
-std::vector<Ref<tree::ParseTreeListener>> Parser::getParseListeners() {
+std::vector<tree::ParseTreeListener *> Parser::getParseListeners() {
   return _parseListeners;
 }
 
-void Parser::addParseListener(Ref<tree::ParseTreeListener> const& listener) {
+void Parser::addParseListener(tree::ParseTreeListener *listener) {
   if (!listener) {
     throw NullPointerException("listener");
   }
@@ -188,7 +188,7 @@ void Parser::addParseListener(Ref<tree::ParseTreeListener> const& listener) {
   this->_parseListeners.push_back(listener);
 }
 
-void Parser::removeParseListener(Ref<tree::ParseTreeListener> const& listener) {
+void Parser::removeParseListener(tree::ParseTreeListener *listener) {
   if (!_parseListeners.empty()) {
     auto it = std::find(_parseListeners.begin(), _parseListeners.end(), listener);
     if (it != _parseListeners.end()) {
@@ -627,11 +627,12 @@ void Parser::setTrace(bool trace) {
   if (!trace) {
     if (_tracer)
       removeParseListener(_tracer);
-    _tracer.reset();
+    delete _tracer;
+    _tracer = nullptr;
   } else {
     if (_tracer)
       removeParseListener(_tracer); // Just in case this is triggered multiple times.
-    _tracer = std::make_shared<TraceListener>(this);
+    _tracer = new TraceListener(this);
     addParseListener(_tracer);
   }
 }
@@ -648,5 +649,6 @@ void Parser::InitializeInstanceFields() {
   _syntaxErrors = 0;
   _matchedEOF = false;
   _input = nullptr;
+  _tracer = nullptr;
 }
 

runtime/Cpp/runtime/src/Parser.h

@@ -59,7 +59,7 @@ namespace antlr4 {
 
     class TrimToSizeListener : public tree::ParseTreeListener {
     public:
-      static const Ref<TrimToSizeListener> INSTANCE;
+      static TrimToSizeListener INSTANCE;
 
       virtual ~TrimToSizeListener() {};
 
@@ -149,7 +149,7 @@ namespace antlr4 {
     /// using the default <seealso cref="Parser.TrimToSizeListener"/> during the parse process. </returns>
     virtual bool getTrimParseTree();
 
-    virtual std::vector<Ref<tree::ParseTreeListener>> getParseListeners();
+    virtual std::vector<tree::ParseTreeListener *> getParseListeners();
 
     /// <summary>
     /// Registers {@code listener} to receive events during the parsing process.
@@ -179,7 +179,7 @@ namespace antlr4 {
     /// <param name="listener"> the listener to add
     /// </param>
     /// <exception cref="NullPointerException"> if {@code} listener is {@code null} </exception>
-    virtual void addParseListener(Ref<tree::ParseTreeListener> const& listener);
+    virtual void addParseListener(tree::ParseTreeListener *listener);
 
     /// <summary>
     /// Remove {@code listener} from the list of parse listeners.
@@ -190,7 +190,7 @@ namespace antlr4 {
     /// <seealso cref= #addParseListener
     /// </seealso>
     /// <param name="listener"> the listener to remove </param>
-    virtual void removeParseListener(Ref<tree::ParseTreeListener> const& listener);
+    virtual void removeParseListener(tree::ParseTreeListener *listener);
 
     /// <summary>
     /// Remove all parse listeners.
@@ -433,12 +433,10 @@ namespace antlr4 {
     /// <seealso cref= #setBuildParseTree </seealso>
     bool _buildParseTrees;
 
-    /// <summary>
     /// The list of <seealso cref="ParseTreeListener"/> listeners registered to receive
     /// events during the parse.
-    /// </summary>
     /// <seealso cref= #addParseListener </seealso>
-    std::vector<Ref<tree::ParseTreeListener>> _parseListeners;
+    std::vector<tree::ParseTreeListener *> _parseListeners;
 
     /// <summary>
     /// The number of syntax errors reported during parsing. This value is
@@ -463,7 +461,7 @@ namespace antlr4 {
     /// later call to setTrace(false). The listener itself is
     /// implemented as a parser listener so this field is not directly used by
     /// other parser methods.
-    Ref<TraceListener> _tracer;
+    TraceListener *_tracer;
 
     void InitializeInstanceFields();
   };

runtime/Cpp/runtime/src/ParserRuleContext.cpp

@@ -58,10 +58,10 @@ ParserRuleContext::ParserRuleContext(std::weak_ptr<ParserRuleContext> parent, in
   : RuleContext(parent, invokingStateNumber) {
 }
 
-void ParserRuleContext::enterRule(Ref<tree::ParseTreeListener> const& /*listener*/) {
+void ParserRuleContext::enterRule(tree::ParseTreeListener * /*listener*/) {
 }
 
-void ParserRuleContext::exitRule(Ref<tree::ParseTreeListener> const& /*listener*/) {
+void ParserRuleContext::exitRule(tree::ParseTreeListener * /*listener*/) {
 }
 
 Ref<tree::TerminalNode> ParserRuleContext::addChild(Ref<tree::TerminalNode> const& t) {

runtime/Cpp/runtime/src/ParserRuleContext.h

@@ -110,8 +110,8 @@ namespace antlr4 {
 
     // Double dispatch methods for listeners
 
-    virtual void enterRule(Ref<tree::ParseTreeListener> const& listener);
-    virtual void exitRule(Ref<tree::ParseTreeListener> const& listener);
+    virtual void enterRule(tree::ParseTreeListener *listener);
+    virtual void exitRule(tree::ParseTreeListener *listener);
 
     /// Does not set parent link; other add methods do that.
     virtual Ref<tree::TerminalNode> addChild(Ref<tree::TerminalNode> const& t);

tool/resources/org/antlr/v4/tool/templates/codegen/Cpp/Cpp.stg

@@ -1026,12 +1026,12 @@ CaptureNextTokenTypeHeader(d) ::= "<! Required but unused. !>"
 CaptureNextTokenType(d) ::= "<d.varName> = _input->LA(1);"
 
 ListenerDispatchMethodHeader(method) ::= <<
-virtual void <if (method.isEnter)>enter<else>exit<endif>Rule(Ref\<tree::ParseTreeListener> const& listener) override;
+virtual void <if (method.isEnter)>enter<else>exit<endif>Rule(tree::ParseTreeListener *listener) override;
 >>
 ListenerDispatchMethod(method) ::= <<
-void <parser.name>::<struct.name>::<if (method.isEnter)>enter<else>exit<endif>Rule(Ref\<tree::ParseTreeListener> const& listener) {
-  auto parserListener = std::dynamic_pointer_cast\<<parser.grammarName>Listener>(listener);
-  if (parserListener)
+void <parser.name>::<struct.name>::<if (method.isEnter)>enter<else>exit<endif>Rule(tree::ParseTreeListener *listener) {
+  auto parserListener = dynamic_cast\<<parser.grammarName>Listener *>(listener);
+  if (parserListener != nullptr)
     parserListener-><if(method.isEnter)>enter<else>exit<endif><struct.derivedFromName; format="cap">(this);
 }
 >>