Support extra parameters for plugins.

src/google/protobuf/compiler/command_line_interface.cc

@@ -262,6 +262,10 @@ void AddDefaultProtoPaths(vector<pair<string, string> >* paths) {
     return;
   }
 }
+
+string PluginName(const string& plugin_prefix, const string& directive) {
+  return plugin_prefix + "gen-" + directive.substr(2, directive.size() - 6);
+}
 }  // namespace
 
 // A MultiFileErrorCollector that prints errors to stderr.
@@ -1007,6 +1011,18 @@ CommandLineInterface::ParseArguments(int argc, const char* const argv[]) {
       return status;
   }
 
+  // Make sure each plugin option has a matching plugin output.
+  for (map<string, string>::const_iterator i = plugin_parameters_.begin();
+       i != plugin_parameters_.end(); ++i) {
+    if (plugins_.find(i->first) == plugins_.end()) {
+      std::cerr << "Unknown flag: "
+                // strip prefix + "gen-" and add back "_opt"
+                << "--" + i->first.substr(plugin_prefix_.size() + 4) + "_opt"
+                << std::endl;
+      return PARSE_ARGUMENT_FAIL;
+    }
+  }
+
   // If no --proto_path was given, use the current working directory.
   if (proto_path_.empty()) {
     // Don't use make_pair as the old/default standard library on Solaris
@@ -1335,15 +1351,22 @@ CommandLineInterface::InterpretArgument(const string& name,
         (plugin_prefix_.empty() || !HasSuffixString(name, "_out"))) {
       // Check if it's a generator option flag.
       generator_info = FindOrNull(generators_by_option_name_, name);
-      if (generator_info == NULL) {
-        std::cerr << "Unknown flag: " << name << std::endl;
-        return PARSE_ARGUMENT_FAIL;
-      } else {
+      if (generator_info != NULL) {
         string* parameters = &generator_parameters_[generator_info->flag_name];
         if (!parameters->empty()) {
           parameters->append(",");
         }
         parameters->append(value);
+      } else if (HasPrefixString(name, "--") && HasSuffixString(name, "_opt")) {
+        string* parameters =
+            &plugin_parameters_[PluginName(plugin_prefix_, name)];
+        if (!parameters->empty()) {
+          parameters->append(",");
+        }
+        parameters->append(value);
+      } else {
+        std::cerr << "Unknown flag: " << name << std::endl;
+        return PARSE_ARGUMENT_FAIL;
       }
     } else {
       // It's an output flag.  Add it to the output directives.
@@ -1463,11 +1486,16 @@ bool CommandLineInterface::GenerateOutput(
         << "Bad name for plugin generator: " << output_directive.name;
 
     // Strip the "--" and "_out" and add the plugin prefix.
-    string plugin_name = plugin_prefix_ + "gen-" +
-        output_directive.name.substr(2, output_directive.name.size() - 6);
-
+    string plugin_name = PluginName(plugin_prefix_ , output_directive.name);
+    string parameters = output_directive.parameter;
+    if (!plugin_parameters_[plugin_name].empty()) {
+      if (!parameters.empty()) {
+        parameters.append(",");
+      }
+      parameters.append(plugin_parameters_[plugin_name]);
+    }
     if (!GeneratePluginOutput(parsed_files, plugin_name,
-                              output_directive.parameter,
+                              parameters,
                               generator_context, &error)) {
       std::cerr << output_directive.name << ": " << error << std::endl;
       return false;

src/google/protobuf/compiler/command_line_interface.h

@@ -146,14 +146,14 @@ class LIBPROTOC_EXPORT CommandLineInterface {
   //   plugin [--out=OUTDIR] [--parameter=PARAMETER] PROTO_FILES < DESCRIPTORS
   // --out indicates the output directory (as passed to the --foo_out
   // parameter); if omitted, the current directory should be used.  --parameter
-  // gives the generator parameter, if any was provided.  The PROTO_FILES list
-  // the .proto files which were given on the compiler command-line; these are
-  // the files for which the plugin is expected to generate output code.
-  // Finally, DESCRIPTORS is an encoded FileDescriptorSet (as defined in
-  // descriptor.proto).  This is piped to the plugin's stdin.  The set will
-  // include descriptors for all the files listed in PROTO_FILES as well as
-  // all files that they import.  The plugin MUST NOT attempt to read the
-  // PROTO_FILES directly -- it must use the FileDescriptorSet.
+  // gives the generator parameter, if any was provided (see below).  The
+  // PROTO_FILES list the .proto files which were given on the compiler
+  // command-line; these are the files for which the plugin is expected to
+  // generate output code.  Finally, DESCRIPTORS is an encoded FileDescriptorSet
+  // (as defined in descriptor.proto).  This is piped to the plugin's stdin.
+  // The set will include descriptors for all the files listed in PROTO_FILES as
+  // well as all files that they import.  The plugin MUST NOT attempt to read
+  // the PROTO_FILES directly -- it must use the FileDescriptorSet.
   //
   // The plugin should generate whatever files are necessary, as code generators
   // normally do.  It should write the names of all files it generates to
@@ -161,6 +161,13 @@ class LIBPROTOC_EXPORT CommandLineInterface {
   // names or relative to the current directory.  If any errors occur, error
   // messages should be written to stderr.  If an error is fatal, the plugin
   // should exit with a non-zero exit code.
+  //
+  // Plugins can have generator parameters similar to normal built-in
+  // generators. Extra generator parameters can be passed in via a matching
+  // "_opt" parameter. For example:
+  //   protoc --plug_out=enable_bar:outdir --plug_opt=enable_baz
+  // This will pass "enable_bar,enable_baz" as the parameter to the plugin.
+  //
   void AllowPlugins(const string& exe_name_prefix);
 
   // Run the Protocol Compiler with the given command-line parameters.
@@ -316,6 +323,8 @@ class LIBPROTOC_EXPORT CommandLineInterface {
   //   protoc --foo_out=outputdir --foo_opt=enable_bar ...
   // Then there will be an entry ("--foo_out", "enable_bar") in this map.
   map<string, string> generator_parameters_;
+  // Similar to generator_parameters_, but stores the parameters for plugins.
+  map<string, string> plugin_parameters_;
 
   // See AllowPlugins().  If this is empty, plugins aren't allowed.
   string plugin_prefix_;

src/google/protobuf/compiler/command_line_interface_unittest.cc

@@ -653,6 +653,44 @@ TEST_F(CommandLineInterfaceTest, ExtraGeneratorParameters) {
       "test_generator", "baz,foo1,foo2,foo3", "foo.proto", "Foo", "b");
 }
 
+TEST_F(CommandLineInterfaceTest, ExtraPluginParameters) {
+  // Test that generator parameters specified with the option flag are
+  // correctly passed to the code generator.
+
+  CreateTempFile("foo.proto",
+    "syntax = \"proto2\";\n"
+    "message Foo {}\n");
+  // Create the "a" and "b" sub-directories.
+  CreateTempDir("a");
+  CreateTempDir("b");
+
+  Run("protocol_compiler "
+      "--plug_opt=foo1 "
+      "--plug_out=bar:$tmpdir/a "
+      "--plug_opt=foo2 "
+      "--plug_out=baz:$tmpdir/b "
+      "--plug_opt=foo3 "
+      "--proto_path=$tmpdir foo.proto");
+
+  ExpectNoErrors();
+  ExpectGenerated(
+      "test_plugin", "bar,foo1,foo2,foo3", "foo.proto", "Foo", "a");
+  ExpectGenerated(
+      "test_plugin", "baz,foo1,foo2,foo3", "foo.proto", "Foo", "b");
+}
+
+TEST_F(CommandLineInterfaceTest, UnrecognizedExtraParameters) {
+  CreateTempFile("foo.proto",
+    "syntax = \"proto2\";\n"
+    "message Foo {}\n");
+
+  Run("protocol_compiler --plug_out=TestParameter:$tmpdir "
+      "--unknown_plug_opt=Foo "
+      "--proto_path=$tmpdir foo.proto");
+
+  ExpectErrorSubstring("Unknown flag: --unknown_plug_opt");
+}
+
 TEST_F(CommandLineInterfaceTest, Insert) {
   // Test running a generator that inserts code into another's output.