tools/proto_to_cpp/proto_to_cpp.cc - third_party/perfetto - Git at Google

 /*
  * Copyright (C) 2017 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include <google/protobuf/compiler/importer.h>
 #include <google/protobuf/dynamic_message.h>
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/io/zero_copy_stream_impl.h>
 #include <google/protobuf/util/field_comparator.h>
 #include <google/protobuf/util/message_differencer.h>

 #include <stdio.h>

 #include <fstream>
 #include <iostream>

 #include "perfetto/base/logging.h"
 #include "perfetto/ext/base/string_utils.h"

 using namespace google::protobuf;
 using namespace google::protobuf::compiler;
 using namespace google::protobuf::io;
 using perfetto::base::SplitString;
 using perfetto::base::StripChars;
 using perfetto::base::StripSuffix;
 using perfetto::base::ToUpper;

 static constexpr auto TYPE_MESSAGE = FieldDescriptor::TYPE_MESSAGE;

 namespace {

 static const char kHeader[] = R"(/*
  * Copyright (C) 2017 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 /*******************************************************************************
  * AUTOGENERATED - DO NOT EDIT
  *******************************************************************************
  * This file has been generated from the protobuf message
  * $p$
  * by
  * $f$.
  * If you need to make changes here, change the .proto file and then run
  * ./tools/gen_tracing_cpp_headers_from_protos
  */

 )";

 class ErrorPrinter : public MultiFileErrorCollector {
   virtual void AddError(const string& filename,
                         int line,
                         int col,
                         const string& msg) {
     PERFETTO_ELOG("%s %d:%d: %s", filename.c_str(), line, col, msg.c_str());
   }
   virtual void AddWarning(const string& filename,
                           int line,
                           int col,
                           const string& msg) {
     PERFETTO_ILOG("%s %d:%d: %s", filename.c_str(), line, col, msg.c_str());
   }
 };

 std::string GetProtoHeader(const FileDescriptor* proto_file) {
   return StripSuffix(proto_file->name(), ".proto") + ".pb.h";
 }

 std::string GetFwdDeclType(const Descriptor* msg, bool with_namespace = false) {
   std::string full_type;
   full_type.append(msg->name());
   for (const Descriptor* par = msg->containing_type(); par;
        par = par->containing_type()) {
     full_type.insert(0, par->name() + "_");
   }
   if (with_namespace) {
     std::vector<std::string> namespaces =
         SplitString(msg->file()->package(), ".");
     for (auto it = namespaces.rbegin(); it != namespaces.rend(); it++) {
       full_type.insert(0, *it + "::");
     }
   }
   return full_type;
 }

 void GenFwdDecl(const Descriptor* msg, Printer* p, bool root_cpp_only = false) {
   if (!root_cpp_only) {
     p->Print("class $n$;", "n", GetFwdDeclType(msg));
   } else if (msg->full_name() == msg->file()->package() + "." + msg->name()) {
     p->Print("class $n$;", "n", msg->name());
   }

   // Recurse into subtypes
   for (int i = 0; i < msg->field_count(); i++) {
     const FieldDescriptor* field = msg->field(i);
     if (field->type() == TYPE_MESSAGE && !field->options().lazy()) {
       GenFwdDecl(field->message_type(), p, root_cpp_only);
     }
   }
 }

 }  // namespace

 class ProtoToCpp {
  public:
   ProtoToCpp(const std::string& header_dir,
              const std::string& cpp_dir,
              const std::string& include_path);

   static std::string GetCppType(const FieldDescriptor* field, bool constref);

   void Convert(const std::string& src_proto);
   std::string GetHeaderPath(const FileDescriptor*);
   std::string GetCppPath(const FileDescriptor*);
   std::string GetIncludePath(const FileDescriptor*);
   void GenHeader(const Descriptor*, Printer*);
   void GenCpp(const Descriptor*, Printer*, std::string prefix);

  private:
   std::string header_dir_;
   std::string cpp_dir_;
   std::string include_path_;
   DiskSourceTree dst_;
   ErrorPrinter error_printer_;
   Importer importer_;
 };

 ProtoToCpp::ProtoToCpp(const std::string& header_dir,
                        const std::string& cpp_dir,
                        const std::string& include_path)
     : header_dir_(header_dir),
       cpp_dir_(cpp_dir),
       include_path_(include_path),
       importer_(&dst_, &error_printer_) {
   dst_.MapPath("", "");  // Yes, this tautology is needed :/.
 }

 std::string ProtoToCpp::GetHeaderPath(const FileDescriptor* proto_file) {
   std::string basename = SplitString(proto_file->name(), "/").back();
   return header_dir_ + "/" + StripSuffix(basename, ".proto") + ".h";
 }

 std::string ProtoToCpp::GetCppPath(const FileDescriptor* proto_file) {
   std::string basename = SplitString(proto_file->name(), "/").back();
   return cpp_dir_ + "/" + StripSuffix(basename, ".proto") + ".cc";
 }

 std::string ProtoToCpp::GetIncludePath(const FileDescriptor* proto_file) {
   std::string basename = SplitString(proto_file->name(), "/").back();
   return include_path_ + "/" + StripSuffix(basename, ".proto") + ".h";
 }

 std::string ProtoToCpp::GetCppType(const FieldDescriptor* field,
                                    bool constref) {
   switch (field->type()) {
     case FieldDescriptor::TYPE_DOUBLE:
       return "double";
     case FieldDescriptor::TYPE_FLOAT:
       return "float";
     case FieldDescriptor::TYPE_FIXED32:
     case FieldDescriptor::TYPE_UINT32:
       return "uint32_t";
     case FieldDescriptor::TYPE_SFIXED32:
     case FieldDescriptor::TYPE_INT32:
     case FieldDescriptor::TYPE_SINT32:
       return "int32_t";
     case FieldDescriptor::TYPE_FIXED64:
     case FieldDescriptor::TYPE_UINT64:
       return "uint64_t";
     case FieldDescriptor::TYPE_SFIXED64:
     case FieldDescriptor::TYPE_SINT64:
     case FieldDescriptor::TYPE_INT64:
       return "int64_t";
     case FieldDescriptor::TYPE_BOOL:
       return "bool";
     case FieldDescriptor::TYPE_STRING:
     case FieldDescriptor::TYPE_BYTES:
       return constref ? "const std::string&" : "std::string";
     case FieldDescriptor::TYPE_MESSAGE:
       PERFETTO_CHECK(!field->options().lazy());
       return constref ? "const " + field->message_type()->name() + "&"
                       : field->message_type()->name();
     case FieldDescriptor::TYPE_ENUM:
       return field->enum_type()->name();
     case FieldDescriptor::TYPE_GROUP:
       PERFETTO_FATAL("No cpp type for a group field.");
   }
   PERFETTO_FATAL("Not reached");  // for gcc
 }

 void ProtoToCpp::Convert(const std::string& src_proto) {
   const FileDescriptor* proto_file = importer_.Import(src_proto);
   if (!proto_file) {
     PERFETTO_ELOG("Failed to load %s", src_proto.c_str());
     exit(1);
   }

   std::string dst_header = GetHeaderPath(proto_file);
   std::string dst_cpp = GetCppPath(proto_file);

   std::ofstream header_ostr;
   header_ostr.open(dst_header);
   PERFETTO_CHECK(header_ostr.is_open());
   OstreamOutputStream header_proto_ostr(&header_ostr);
   Printer header_printer(&header_proto_ostr, '$');

   std::ofstream cpp_ostr;
   cpp_ostr.open(dst_cpp);
   PERFETTO_CHECK(cpp_ostr.is_open());
   OstreamOutputStream cpp_proto_ostr(&cpp_ostr);
   Printer cpp_printer(&cpp_proto_ostr, '$');

   std::string include_guard = dst_header + "_";
   include_guard = ToUpper(include_guard);
   include_guard = StripChars(include_guard, ".-/\\", '_');
   header_printer.Print(kHeader, "f", __FILE__, "p", src_proto);
   header_printer.Print("#ifndef $g$\n#define $g$\n\n", "g", include_guard);
   header_printer.Print("#include <stdint.h>\n");
   header_printer.Print("#include <vector>\n");
   header_printer.Print("#include <string>\n");
   header_printer.Print("#include <type_traits>\n\n");
   header_printer.Print("#include \"perfetto/base/copyable_ptr.h\"\n");
   header_printer.Print("#include \"perfetto/base/export.h\"\n\n");

   cpp_printer.Print(kHeader, "f", __FILE__, "p", src_proto);
   if (dst_header.find("include/") == 0) {
     cpp_printer.Print("#include \"$f$\"\n", "f",
                       dst_header.substr(strlen("include/")));
   } else {
     cpp_printer.Print("#include \"$f$\"\n", "f", dst_header);
   }

   // Generate includes for translated types of dependencies.

   // Figure out the subset of imports that are used only for lazy fields. We
   // won't emit a C++ #include for them. This code is overly aggressive at
   // removing imports: it rules them out as soon as it sees one lazy field
   // whose type is defined in that import. A 100% correct solution would require
   // to check that *all* dependent types for a given import are lazy before
   // excluding that. In practice we don't need that because we don't use imports
   // for both lazy and non-lazy fields.
   std::set<std::string> lazy_imports;
   for (int m = 0; m < proto_file->message_type_count(); m++) {
     const Descriptor* msg = proto_file->message_type(m);
     for (int i = 0; i < msg->field_count(); i++) {
       const FieldDescriptor* field = msg->field(i);
       if (field->options().lazy()) {
         lazy_imports.insert(field->message_type()->file()->name());
       }
     }
   }

   cpp_printer.Print("\n#include \"$f$\"\n", "f", GetProtoHeader(proto_file));
   for (int i = 0; i < proto_file->dependency_count(); i++) {
     const FileDescriptor* dep = proto_file->dependency(i);
     if (lazy_imports.count(dep->name()))
       continue;
     cpp_printer.Print("\n#include \"$f$\"\n", "f", GetIncludePath(dep));
     cpp_printer.Print("#include \"$f$\"\n", "f", GetProtoHeader(dep));
   }

   // Generate forward declarations in the header for proto types.
   header_printer.Print("// Forward declarations for protobuf types.\n");
   std::vector<std::string> namespaces = SplitString(proto_file->package(), ".");
   for (size_t i = 0; i < namespaces.size(); i++)
     header_printer.Print("namespace $n$ {\n", "n", namespaces[i]);
   for (int i = 0; i < proto_file->message_type_count(); i++)
     GenFwdDecl(proto_file->message_type(i), &header_printer);
   for (size_t i = 0; i < namespaces.size(); i++)
     header_printer.Print("}\n");

   header_printer.Print("\nnamespace perfetto {\n");
   cpp_printer.Print("\nnamespace perfetto {\n");

   // Generate fwd declarations for top-level classes.
   for (int i = 0; i < proto_file->message_type_count(); i++)
     GenFwdDecl(proto_file->message_type(i), &header_printer, true);
   header_printer.Print("\n");

   for (int i = 0; i < proto_file->message_type_count(); i++) {
     const Descriptor* msg = proto_file->message_type(i);
     GenHeader(msg, &header_printer);
     GenCpp(msg, &cpp_printer, "");
   }

   cpp_printer.Print("}  // namespace perfetto\n");
   header_printer.Print("}  // namespace perfetto\n");
   header_printer.Print("\n#endif  // $g$\n", "g", include_guard);
 }

 void ProtoToCpp::GenHeader(const Descriptor* msg, Printer* p) {
   PERFETTO_ILOG("GEN %s %s", msg->name().c_str(), msg->file()->name().c_str());
   p->Print("\nclass PERFETTO_EXPORT $n$ {\n", "n", msg->name());
   p->Print(" public:\n");
   p->Indent();
   // Do a first pass to generate nested types.
   for (int i = 0; i < msg->field_count(); i++) {
     const FieldDescriptor* field = msg->field(i);
     if (field->has_default_value()) {
       PERFETTO_FATAL(
           "Error on field %s: Explicitly declared default values are not "
           "supported",
           field->name().c_str());
     }

     if (field->type() == FieldDescriptor::TYPE_ENUM) {
       const EnumDescriptor* enum_desc = field->enum_type();
       p->Print("enum $n$ {\n", "n", enum_desc->name());
       for (int e = 0; e < enum_desc->value_count(); e++) {
         const EnumValueDescriptor* value = enum_desc->value(e);
         p->Print("  $n$ = $v$,\n", "n", value->name(), "v",
                  std::to_string(value->number()));
       }
       p->Print("};\n");
     } else if (field->type() == TYPE_MESSAGE &&
                field->message_type()->file() == msg->file()) {
       GenHeader(field->message_type(), p);
     }
   }

   p->Print("$n$();\n", "n", msg->name());
   p->Print("~$n$();\n", "n", msg->name());
   p->Print("$n$($n$&&) noexcept;\n", "n", msg->name());
   p->Print("$n$& operator=($n$&&);\n", "n", msg->name());
   p->Print("$n$(const $n$&);\n", "n", msg->name());
   p->Print("$n$& operator=(const $n$&);\n", "n", msg->name());
   p->Print("bool operator==(const $n$&) const;\n", "n", msg->name());
   p->Print(
       "bool operator!=(const $n$& other) const { return !(*this == other); }\n",
       "n", msg->name());
   p->Print("\n");

   std::string proto_type = GetFwdDeclType(msg, true);
   p->Print("// Raw proto decoding.\n");
   p->Print("void ParseRawProto(const std::string&);\n");
   p->Print("// Conversion methods from/to the corresponding protobuf types.\n");
   p->Print("void FromProto(const $p$&);\n", "p", proto_type);
   p->Print("void ToProto($p$*) const;\n", "p", proto_type);

   // Generate accessors.
   for (int i = 0; i < msg->field_count(); i++) {
     const FieldDescriptor* field = msg->field(i);
     p->Print("\n");
     if (field->options().lazy()) {
       if (field->is_repeated() || field->type() != TYPE_MESSAGE) {
         PERFETTO_FATAL(
             "[lazy=true] is supported only on non-repeated submessage fields");
       }
       p->Print("const std::string& $n$_raw() const { return $n$_; }\n", "n",
                field->lowercase_name());
       p->Print("void set_$n$_raw(const std::string& raw) { $n$_ = raw; }\n",
                "n", field->lowercase_name());
     } else if (!field->is_repeated()) {
       if (field->type() == TYPE_MESSAGE) {
         p->Print("$t$ $n$() const { return *$n$_; }\n", "t",
                  GetCppType(field, true), "n", field->lowercase_name());
         p->Print("$t$* mutable_$n$() { return $n$_.get(); }\n", "t",
                  GetCppType(field, false), "n", field->lowercase_name());
       } else {
         p->Print("$t$ $n$() const { return $n$_; }\n", "t",
                  GetCppType(field, true), "n", field->lowercase_name());
         p->Print("void set_$n$($t$ value) { $n$_ = value; }\n", "t",
                  GetCppType(field, true), "n", field->lowercase_name());
         if (field->type() == FieldDescriptor::TYPE_BYTES) {
           p->Print(
               "void set_$n$(const void* p, size_t s) { "
               "$n$_.assign(reinterpret_cast<const char*>(p), s); }\n",
               "n", field->lowercase_name());
         }
       }
     } else {  // is_repeated()
       p->Print(
           "int $n$_size() const { return static_cast<int>($n$_.size()); }\n",
           "t", GetCppType(field, false), "n", field->lowercase_name());
       p->Print("const std::vector<$t$>& $n$() const { return $n$_; }\n", "t",
                GetCppType(field, false), "n", field->lowercase_name());
       p->Print("std::vector<$t$>* mutable_$n$() { return &$n$_; }\n", "t",
                GetCppType(field, false), "n", field->lowercase_name());
       p->Print("void clear_$n$() { $n$_.clear(); }\n", "n",
                field->lowercase_name());

       if (field->type() == TYPE_MESSAGE && !field->options().lazy()) {
         p->Print(
             "$t$* add_$n$() { $n$_.emplace_back(); return &$n$_.back(); "
             "}\n",
             "t", GetCppType(field, false), "n", field->lowercase_name());
       } else {
         p->Print(
             "$t$* add_$n$() { $n$_.emplace_back(); return &$n$_.back(); }\n",
             "t", GetCppType(field, false), "n", field->lowercase_name());
       }
     }
   }
   p->Outdent();
   p->Print("\n private:\n");
   p->Indent();

   // Generate fields.
   for (int i = 0; i < msg->field_count(); i++) {
     const FieldDescriptor* field = msg->field(i);
     if (field->options().lazy()) {
       p->Print("std::string $n$_;  // [lazy=true]\n", "n",
                field->lowercase_name());
     } else if (!field->is_repeated()) {
       std::string type = GetCppType(field, false);
       if (field->type() == TYPE_MESSAGE) {
         type = "::perfetto::base::CopyablePtr<" + type + ">";
         p->Print("$t$ $n$_;\n", "t", type, "n", field->lowercase_name());
       } else {
         p->Print("$t$ $n$_{};\n", "t", type, "n", field->lowercase_name());
       }
     } else {  // is_repeated()
       p->Print("std::vector<$t$> $n$_;\n", "t", GetCppType(field, false), "n",
                field->lowercase_name());
     }
   }
   p->Print("\n");
   p->Print("// Allows to preserve unknown protobuf fields for compatibility\n");
   p->Print("// with future versions of .proto files.\n");
   p->Print("std::string unknown_fields_;\n");
   p->Outdent();
   p->Print("};\n\n");
 }

 void ProtoToCpp::GenCpp(const Descriptor* msg, Printer* p, std::string prefix) {
   p->Print("\n");
   std::string full_name = prefix + msg->name();

   p->Print("$f$::$n$() = default;\n", "f", full_name, "n", msg->name());
   p->Print("$f$::~$n$() = default;\n", "f", full_name, "n", msg->name());
   p->Print("$f$::$n$(const $f$&) = default;\n", "f", full_name, "n",
            msg->name());
   p->Print("$f$& $f$::operator=(const $f$&) = default;\n", "f", full_name, "n",
            msg->name());
   p->Print("$f$::$n$($f$&&) noexcept = default;\n", "f", full_name, "n",
            msg->name());
   p->Print("$f$& $f$::operator=($f$&&) = default;\n", "f", full_name, "n",
            msg->name());

   p->Print("\n");

   // Comparison operator
   p->Print("#pragma GCC diagnostic push\n");
   p->Print("#pragma GCC diagnostic ignored \"-Wfloat-equal\"\n");
   p->Print("bool $f$::operator==(const $f$& other) const {\n", "f", full_name,
            "n", msg->name());
   p->Indent();

   p->Print("return ");
   for (int i = 0; i < msg->field_count(); i++) {
     if (i > 0)
       p->Print("\n && ");
     const FieldDescriptor* field = msg->field(i);
     p->Print("($n$_ == other.$n$_)", "n", field->name());
   }
   p->Print(";");
   p->Outdent();
   p->Print("}\n");
   p->Print("#pragma GCC diagnostic pop\n\n");

   std::string proto_type = GetFwdDeclType(msg, true);

   // Genrate the ParseRawProto() method definition.
   p->Print("void $f$::ParseRawProto(const std::string& raw) {\n", "f",
            full_name);
   p->Indent();
   p->Print("$p$ proto;\n", "p", proto_type);
   p->Print("proto.ParseFromString(raw);\n");
   p->Print("FromProto(proto);\n");
   p->Outdent();
   p->Print("}\n\n");

   // Genrate the FromProto() method definition.
   p->Print("void $f$::FromProto(const $p$& proto) {\n", "f", full_name, "p",
            proto_type);
   p->Indent();
   for (int i = 0; i < msg->field_count(); i++) {
     p->Print("\n");
     const FieldDescriptor* field = msg->field(i);
     if (field->options().lazy()) {
       p->Print("$n$_ = proto.$n$().SerializeAsString();\n", "n", field->name());
     } else if (!field->is_repeated()) {
       if (field->type() == TYPE_MESSAGE) {
         p->Print("$n$_->FromProto(proto.$n$());\n", "n", field->name());
       } else {
         p->Print(
             "static_assert(sizeof($n$_) == sizeof(proto.$n$()), \"size "
             "mismatch\");\n",
             "n", field->name());
         p->Print("$n$_ = static_cast<decltype($n$_)>(proto.$n$());\n", "n",
                  field->name());
       }
     } else {  // is_repeated()
       p->Print("$n$_.clear();\n", "n", field->name());
       p->Print("for (const auto& field : proto.$n$()) {\n", "n", field->name());
       p->Print("  $n$_.emplace_back();\n", "n", field->name());
       if (field->type() == TYPE_MESSAGE) {
         p->Print("  $n$_.back().FromProto(field);\n", "n", field->name());
       } else {
         p->Print(
             "static_assert(sizeof($n$_.back()) == sizeof(proto.$n$(0)), \"size "
             "mismatch\");\n",
             "n", field->name());
         p->Print(
             "  $n$_.back() = static_cast<decltype($n$_)::value_type>(field);\n",
             "n", field->name());
       }
       p->Print("}\n");
     }
   }
   p->Print("unknown_fields_ = proto.unknown_fields();\n");
   p->Outdent();
   p->Print("}\n\n");

   // Genrate the ToProto() method definition.
   p->Print("void $f$::ToProto($p$* proto) const {\n", "f", full_name, "p",
            proto_type);
   p->Indent();
   p->Print("proto->Clear();\n");
   for (int i = 0; i < msg->field_count(); i++) {
     p->Print("\n");
     const FieldDescriptor* field = msg->field(i);
     if (field->options().lazy()) {
       p->Print("proto->mutable_$n$()->ParseFromString($n$_);\n", "n",
                field->name());
     } else if (!field->is_repeated()) {
       if (field->type() == TYPE_MESSAGE) {
         p->Print("$n$_->ToProto(proto->mutable_$n$());\n", "n", field->name());
       } else {
         p->Print(
             "static_assert(sizeof($n$_) == sizeof(proto->$n$()), \"size "
             "mismatch\");\n",
             "n", field->name());
         p->Print("proto->set_$n$(static_cast<decltype(proto->$n$())>($n$_));\n",
                  "n", field->name());
       }
     } else {  // is_repeated()
       p->Print("for (const auto& it : $n$_) {\n", "n", field->name());
       if (field->type() == TYPE_MESSAGE) {
         p->Print("  auto* entry = proto->add_$n$();\n", "n", field->name());
         p->Print("  it.ToProto(entry);\n");
       } else {
         p->Print(
             "  proto->add_$n$(static_cast<decltype(proto->$n$(0))>(it));\n",
             "n", field->name());
         p->Print(
             "static_assert(sizeof(it) == sizeof(proto->$n$(0)), \"size "
             "mismatch\");\n",
             "n", field->name());
       }
       p->Print("}\n");
     }
   }
   p->Print("*(proto->mutable_unknown_fields()) = unknown_fields_;\n");
   p->Outdent();
   p->Print("}\n\n");

   // Recurse into nested types.
   for (int i = 0; i < msg->field_count(); i++) {
     const FieldDescriptor* field = msg->field(i);
     // [lazy=true] field are not recursesd and exposed as raw-strings
     // containing proto-encoded bytes.
     if (field->options().lazy())
       continue;

     if (field->type() == TYPE_MESSAGE &&
         field->message_type()->file() == msg->file()) {
       std::string child_prefix = prefix + msg->name() + "::";
       GenCpp(field->message_type(), p, child_prefix);
     }
   }
 }

 int main(int argc, char** argv) {
   if (argc <= 4) {
     PERFETTO_ELOG(
         "Usage: %s source.proto dir/for/header dir/for/cc include/path",
         argv[0]);
     return 1;
   }
   ProtoToCpp proto_to_cpp(argv[2], argv[3], argv[4]);
   proto_to_cpp.Convert(argv[1]);
   return 0;
 }
	/*
	* Copyright (C) 2017 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include <google/protobuf/compiler/importer.h>
	#include <google/protobuf/dynamic_message.h>
	#include <google/protobuf/io/printer.h>
	#include <google/protobuf/io/zero_copy_stream_impl.h>
	#include <google/protobuf/util/field_comparator.h>
	#include <google/protobuf/util/message_differencer.h>

	#include <stdio.h>

	#include <fstream>
	#include <iostream>

	#include "perfetto/base/logging.h"
	#include "perfetto/ext/base/string_utils.h"

	using namespace google::protobuf;
	using namespace google::protobuf::compiler;
	using namespace google::protobuf::io;
	using perfetto::base::SplitString;
	using perfetto::base::StripChars;
	using perfetto::base::StripSuffix;
	using perfetto::base::ToUpper;

	static constexpr auto TYPE_MESSAGE = FieldDescriptor::TYPE_MESSAGE;

	namespace {

	static const char kHeader[] = R"(/*
	* Copyright (C) 2017 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	/*******************************************************************************
	* AUTOGENERATED - DO NOT EDIT
	*******************************************************************************
	* This file has been generated from the protobuf message
	* $p$
	* by
	* $f$.
	* If you need to make changes here, change the .proto file and then run
	* ./tools/gen_tracing_cpp_headers_from_protos
	*/

	)";

	class ErrorPrinter : public MultiFileErrorCollector {
	virtual void AddError(const string& filename,
	int line,
	int col,
	const string& msg) {
	PERFETTO_ELOG("%s %d:%d: %s", filename.c_str(), line, col, msg.c_str());
	}
	virtual void AddWarning(const string& filename,
	int line,
	int col,
	const string& msg) {
	PERFETTO_ILOG("%s %d:%d: %s", filename.c_str(), line, col, msg.c_str());
	}
	};

	std::string GetProtoHeader(const FileDescriptor* proto_file) {
	return StripSuffix(proto_file->name(), ".proto") + ".pb.h";
	}

	std::string GetFwdDeclType(const Descriptor* msg, bool with_namespace = false) {
	std::string full_type;
	full_type.append(msg->name());
	for (const Descriptor* par = msg->containing_type(); par;
	par = par->containing_type()) {
	full_type.insert(0, par->name() + "_");
	}
	if (with_namespace) {
	std::vector<std::string> namespaces =
	SplitString(msg->file()->package(), ".");
	for (auto it = namespaces.rbegin(); it != namespaces.rend(); it++) {
	full_type.insert(0, *it + "::");
	}
	}
	return full_type;
	}

	void GenFwdDecl(const Descriptor* msg, Printer* p, bool root_cpp_only = false) {
	if (!root_cpp_only) {
	p->Print("class $n$;", "n", GetFwdDeclType(msg));
	} else if (msg->full_name() == msg->file()->package() + "." + msg->name()) {
	p->Print("class $n$;", "n", msg->name());
	}

	// Recurse into subtypes
	for (int i = 0; i < msg->field_count(); i++) {
	const FieldDescriptor* field = msg->field(i);
	if (field->type() == TYPE_MESSAGE && !field->options().lazy()) {
	GenFwdDecl(field->message_type(), p, root_cpp_only);
	}
	}
	}

	} // namespace

	class ProtoToCpp {
	public:
	ProtoToCpp(const std::string& header_dir,
	const std::string& cpp_dir,
	const std::string& include_path);

	static std::string GetCppType(const FieldDescriptor* field, bool constref);

	void Convert(const std::string& src_proto);
	std::string GetHeaderPath(const FileDescriptor*);
	std::string GetCppPath(const FileDescriptor*);
	std::string GetIncludePath(const FileDescriptor*);
	void GenHeader(const Descriptor, Printer);
	void GenCpp(const Descriptor, Printer, std::string prefix);

	private:
	std::string header_dir_;
	std::string cpp_dir_;
	std::string include_path_;
	DiskSourceTree dst_;
	ErrorPrinter error_printer_;
	Importer importer_;
	};

	ProtoToCpp::ProtoToCpp(const std::string& header_dir,
	const std::string& cpp_dir,
	const std::string& include_path)
	: header_dir_(header_dir),
	cpp_dir_(cpp_dir),
	include_path_(include_path),
	importer_(&dst_, &error_printer_) {
	dst_.MapPath("", ""); // Yes, this tautology is needed :/.
	}

	std::string ProtoToCpp::GetHeaderPath(const FileDescriptor* proto_file) {
	std::string basename = SplitString(proto_file->name(), "/").back();
	return header_dir_ + "/" + StripSuffix(basename, ".proto") + ".h";
	}

	std::string ProtoToCpp::GetCppPath(const FileDescriptor* proto_file) {
	std::string basename = SplitString(proto_file->name(), "/").back();
	return cpp_dir_ + "/" + StripSuffix(basename, ".proto") + ".cc";
	}

	std::string ProtoToCpp::GetIncludePath(const FileDescriptor* proto_file) {
	std::string basename = SplitString(proto_file->name(), "/").back();
	return include_path_ + "/" + StripSuffix(basename, ".proto") + ".h";
	}

	std::string ProtoToCpp::GetCppType(const FieldDescriptor* field,
	bool constref) {
	switch (field->type()) {
	case FieldDescriptor::TYPE_DOUBLE:
	return "double";
	case FieldDescriptor::TYPE_FLOAT:
	return "float";
	case FieldDescriptor::TYPE_FIXED32:
	case FieldDescriptor::TYPE_UINT32:
	return "uint32_t";
	case FieldDescriptor::TYPE_SFIXED32:
	case FieldDescriptor::TYPE_INT32:
	case FieldDescriptor::TYPE_SINT32:
	return "int32_t";
	case FieldDescriptor::TYPE_FIXED64:
	case FieldDescriptor::TYPE_UINT64:
	return "uint64_t";
	case FieldDescriptor::TYPE_SFIXED64:
	case FieldDescriptor::TYPE_SINT64:
	case FieldDescriptor::TYPE_INT64:
	return "int64_t";
	case FieldDescriptor::TYPE_BOOL:
	return "bool";
	case FieldDescriptor::TYPE_STRING:
	case FieldDescriptor::TYPE_BYTES:
	return constref ? "const std::string&" : "std::string";
	case FieldDescriptor::TYPE_MESSAGE:
	PERFETTO_CHECK(!field->options().lazy());
	return constref ? "const " + field->message_type()->name() + "&"
	: field->message_type()->name();
	case FieldDescriptor::TYPE_ENUM:
	return field->enum_type()->name();
	case FieldDescriptor::TYPE_GROUP:
	PERFETTO_FATAL("No cpp type for a group field.");
	}
	PERFETTO_FATAL("Not reached"); // for gcc
	}

	void ProtoToCpp::Convert(const std::string& src_proto) {
	const FileDescriptor* proto_file = importer_.Import(src_proto);
	if (!proto_file) {
	PERFETTO_ELOG("Failed to load %s", src_proto.c_str());
	exit(1);
	}

	std::string dst_header = GetHeaderPath(proto_file);
	std::string dst_cpp = GetCppPath(proto_file);

	std::ofstream header_ostr;
	header_ostr.open(dst_header);
	PERFETTO_CHECK(header_ostr.is_open());
	OstreamOutputStream header_proto_ostr(&header_ostr);
	Printer header_printer(&header_proto_ostr, '$');

	std::ofstream cpp_ostr;
	cpp_ostr.open(dst_cpp);
	PERFETTO_CHECK(cpp_ostr.is_open());
	OstreamOutputStream cpp_proto_ostr(&cpp_ostr);
	Printer cpp_printer(&cpp_proto_ostr, '$');

	std::string include_guard = dst_header + "_";
	include_guard = ToUpper(include_guard);
	include_guard = StripChars(include_guard, ".-/\\", '_');
	header_printer.Print(kHeader, "f", __FILE__, "p", src_proto);
	header_printer.Print("#ifndef $g$\n#define $g$\n\n", "g", include_guard);
	header_printer.Print("#include <stdint.h>\n");
	header_printer.Print("#include <vector>\n");
	header_printer.Print("#include <string>\n");
	header_printer.Print("#include <type_traits>\n\n");
	header_printer.Print("#include \"perfetto/base/copyable_ptr.h\"\n");
	header_printer.Print("#include \"perfetto/base/export.h\"\n\n");

	cpp_printer.Print(kHeader, "f", __FILE__, "p", src_proto);
	if (dst_header.find("include/") == 0) {
	cpp_printer.Print("#include \"$f$\"\n", "f",
	dst_header.substr(strlen("include/")));
	} else {
	cpp_printer.Print("#include \"$f$\"\n", "f", dst_header);
	}

	// Generate includes for translated types of dependencies.

	// Figure out the subset of imports that are used only for lazy fields. We
	// won't emit a C++ #include for them. This code is overly aggressive at
	// removing imports: it rules them out as soon as it sees one lazy field
	// whose type is defined in that import. A 100% correct solution would require
	// to check that all dependent types for a given import are lazy before
	// excluding that. In practice we don't need that because we don't use imports
	// for both lazy and non-lazy fields.
	std::set<std::string> lazy_imports;
	for (int m = 0; m < proto_file->message_type_count(); m++) {
	const Descriptor* msg = proto_file->message_type(m);
	for (int i = 0; i < msg->field_count(); i++) {
	const FieldDescriptor* field = msg->field(i);
	if (field->options().lazy()) {
	lazy_imports.insert(field->message_type()->file()->name());
	}
	}
	}

	cpp_printer.Print("\n#include \"$f$\"\n", "f", GetProtoHeader(proto_file));
	for (int i = 0; i < proto_file->dependency_count(); i++) {
	const FileDescriptor* dep = proto_file->dependency(i);
	if (lazy_imports.count(dep->name()))
	continue;
	cpp_printer.Print("\n#include \"$f$\"\n", "f", GetIncludePath(dep));
	cpp_printer.Print("#include \"$f$\"\n", "f", GetProtoHeader(dep));
	}

	// Generate forward declarations in the header for proto types.
	header_printer.Print("// Forward declarations for protobuf types.\n");
	std::vector<std::string> namespaces = SplitString(proto_file->package(), ".");
	for (size_t i = 0; i < namespaces.size(); i++)
	header_printer.Print("namespace $n$ {\n", "n", namespaces[i]);
	for (int i = 0; i < proto_file->message_type_count(); i++)
	GenFwdDecl(proto_file->message_type(i), &header_printer);
	for (size_t i = 0; i < namespaces.size(); i++)
	header_printer.Print("}\n");

	header_printer.Print("\nnamespace perfetto {\n");
	cpp_printer.Print("\nnamespace perfetto {\n");

	// Generate fwd declarations for top-level classes.
	for (int i = 0; i < proto_file->message_type_count(); i++)
	GenFwdDecl(proto_file->message_type(i), &header_printer, true);
	header_printer.Print("\n");

	for (int i = 0; i < proto_file->message_type_count(); i++) {
	const Descriptor* msg = proto_file->message_type(i);
	GenHeader(msg, &header_printer);
	GenCpp(msg, &cpp_printer, "");
	}

	cpp_printer.Print("} // namespace perfetto\n");
	header_printer.Print("} // namespace perfetto\n");
	header_printer.Print("\n#endif // $g$\n", "g", include_guard);
	}

	void ProtoToCpp::GenHeader(const Descriptor* msg, Printer* p) {
	PERFETTO_ILOG("GEN %s %s", msg->name().c_str(), msg->file()->name().c_str());
	p->Print("\nclass PERFETTO_EXPORT $n$ {\n", "n", msg->name());
	p->Print(" public:\n");
	p->Indent();
	// Do a first pass to generate nested types.
	for (int i = 0; i < msg->field_count(); i++) {
	const FieldDescriptor* field = msg->field(i);
	if (field->has_default_value()) {
	PERFETTO_FATAL(
	"Error on field %s: Explicitly declared default values are not "
	"supported",
	field->name().c_str());
	}

	if (field->type() == FieldDescriptor::TYPE_ENUM) {
	const EnumDescriptor* enum_desc = field->enum_type();
	p->Print("enum $n$ {\n", "n", enum_desc->name());
	for (int e = 0; e < enum_desc->value_count(); e++) {
	const EnumValueDescriptor* value = enum_desc->value(e);
	p->Print(" $n$ = $v$,\n", "n", value->name(), "v",
	std::to_string(value->number()));
	}
	p->Print("};\n");
	} else if (field->type() == TYPE_MESSAGE &&
	field->message_type()->file() == msg->file()) {
	GenHeader(field->message_type(), p);
	}
	}

	p->Print("$n$();\n", "n", msg->name());
	p->Print("~$n$();\n", "n", msg->name());
	p->Print("$n$($n$&&) noexcept;\n", "n", msg->name());
	p->Print("$n$& operator=($n$&&);\n", "n", msg->name());
	p->Print("$n$(const $n$&);\n", "n", msg->name());
	p->Print("$n$& operator=(const $n$&);\n", "n", msg->name());
	p->Print("bool operator==(const $n$&) const;\n", "n", msg->name());
	p->Print(
	"bool operator!=(const $n$& other) const { return !(*this == other); }\n",
	"n", msg->name());
	p->Print("\n");

	std::string proto_type = GetFwdDeclType(msg, true);
	p->Print("// Raw proto decoding.\n");
	p->Print("void ParseRawProto(const std::string&);\n");
	p->Print("// Conversion methods from/to the corresponding protobuf types.\n");
	p->Print("void FromProto(const $p$&);\n", "p", proto_type);
	p->Print("void ToProto($p$*) const;\n", "p", proto_type);

	// Generate accessors.
	for (int i = 0; i < msg->field_count(); i++) {
	const FieldDescriptor* field = msg->field(i);
	p->Print("\n");
	if (field->options().lazy()) {
	if (field->is_repeated() \|\| field->type() != TYPE_MESSAGE) {
	PERFETTO_FATAL(
	"[lazy=true] is supported only on non-repeated submessage fields");
	}
	p->Print("const std::string& $n$_raw() const { return $n$_; }\n", "n",
	field->lowercase_name());
	p->Print("void set_$n$_raw(const std::string& raw) { $n$_ = raw; }\n",
	"n", field->lowercase_name());
	} else if (!field->is_repeated()) {
	if (field->type() == TYPE_MESSAGE) {
	p->Print("$t$ $n$() const { return *$n$_; }\n", "t",
	GetCppType(field, true), "n", field->lowercase_name());
	p->Print("$t$* mutable_$n$() { return $n$_.get(); }\n", "t",
	GetCppType(field, false), "n", field->lowercase_name());
	} else {
	p->Print("$t$ $n$() const { return $n$_; }\n", "t",
	GetCppType(field, true), "n", field->lowercase_name());
	p->Print("void set_$n$($t$ value) { $n$_ = value; }\n", "t",
	GetCppType(field, true), "n", field->lowercase_name());
	if (field->type() == FieldDescriptor::TYPE_BYTES) {
	p->Print(
	"void set_$n$(const void* p, size_t s) { "
	"$n$_.assign(reinterpret_cast<const char*>(p), s); }\n",
	"n", field->lowercase_name());
	}
	}
	} else { // is_repeated()
	p->Print(
	"int $n$_size() const { return static_cast<int>($n$_.size()); }\n",
	"t", GetCppType(field, false), "n", field->lowercase_name());
	p->Print("const std::vector<$t$>& $n$() const { return $n$_; }\n", "t",
	GetCppType(field, false), "n", field->lowercase_name());
	p->Print("std::vector<$t$>* mutable_$n$() { return &$n$_; }\n", "t",
	GetCppType(field, false), "n", field->lowercase_name());
	p->Print("void clear_$n$() { $n$_.clear(); }\n", "n",
	field->lowercase_name());

	if (field->type() == TYPE_MESSAGE && !field->options().lazy()) {
	p->Print(
	"$t$* add_$n$() { $n$_.emplace_back(); return &$n$_.back(); "
	"}\n",
	"t", GetCppType(field, false), "n", field->lowercase_name());
	} else {
	p->Print(
	"$t$* add_$n$() { $n$_.emplace_back(); return &$n$_.back(); }\n",
	"t", GetCppType(field, false), "n", field->lowercase_name());
	}
	}
	}
	p->Outdent();
	p->Print("\n private:\n");
	p->Indent();

	// Generate fields.
	for (int i = 0; i < msg->field_count(); i++) {
	const FieldDescriptor* field = msg->field(i);
	if (field->options().lazy()) {
	p->Print("std::string $n$_; // [lazy=true]\n", "n",
	field->lowercase_name());
	} else if (!field->is_repeated()) {
	std::string type = GetCppType(field, false);
	if (field->type() == TYPE_MESSAGE) {
	type = "::perfetto::base::CopyablePtr<" + type + ">";
	p->Print("$t$ $n$_;\n", "t", type, "n", field->lowercase_name());
	} else {
	p->Print("$t$ $n$_{};\n", "t", type, "n", field->lowercase_name());
	}
	} else { // is_repeated()
	p->Print("std::vector<$t$> $n$_;\n", "t", GetCppType(field, false), "n",
	field->lowercase_name());
	}
	}
	p->Print("\n");
	p->Print("// Allows to preserve unknown protobuf fields for compatibility\n");
	p->Print("// with future versions of .proto files.\n");
	p->Print("std::string unknown_fields_;\n");
	p->Outdent();
	p->Print("};\n\n");
	}

	void ProtoToCpp::GenCpp(const Descriptor* msg, Printer* p, std::string prefix) {
	p->Print("\n");
	std::string full_name = prefix + msg->name();

	p->Print("$f$::$n$() = default;\n", "f", full_name, "n", msg->name());
	p->Print("$f$::~$n$() = default;\n", "f", full_name, "n", msg->name());
	p->Print("$f$::$n$(const $f$&) = default;\n", "f", full_name, "n",
	msg->name());
	p->Print("$f$& $f$::operator=(const $f$&) = default;\n", "f", full_name, "n",
	msg->name());
	p->Print("$f$::$n$($f$&&) noexcept = default;\n", "f", full_name, "n",
	msg->name());
	p->Print("$f$& $f$::operator=($f$&&) = default;\n", "f", full_name, "n",
	msg->name());

	p->Print("\n");

	// Comparison operator
	p->Print("#pragma GCC diagnostic push\n");
	p->Print("#pragma GCC diagnostic ignored \"-Wfloat-equal\"\n");
	p->Print("bool $f$::operator==(const $f$& other) const {\n", "f", full_name,
	"n", msg->name());
	p->Indent();

	p->Print("return ");
	for (int i = 0; i < msg->field_count(); i++) {
	if (i > 0)
	p->Print("\n && ");
	const FieldDescriptor* field = msg->field(i);
	p->Print("($n$_ == other.$n$_)", "n", field->name());
	}
	p->Print(";");
	p->Outdent();
	p->Print("}\n");
	p->Print("#pragma GCC diagnostic pop\n\n");

	std::string proto_type = GetFwdDeclType(msg, true);

	// Genrate the ParseRawProto() method definition.
	p->Print("void $f$::ParseRawProto(const std::string& raw) {\n", "f",
	full_name);
	p->Indent();
	p->Print("$p$ proto;\n", "p", proto_type);
	p->Print("proto.ParseFromString(raw);\n");
	p->Print("FromProto(proto);\n");
	p->Outdent();
	p->Print("}\n\n");

	// Genrate the FromProto() method definition.
	p->Print("void $f$::FromProto(const $p$& proto) {\n", "f", full_name, "p",
	proto_type);
	p->Indent();
	for (int i = 0; i < msg->field_count(); i++) {
	p->Print("\n");
	const FieldDescriptor* field = msg->field(i);
	if (field->options().lazy()) {
	p->Print("$n$_ = proto.$n$().SerializeAsString();\n", "n", field->name());
	} else if (!field->is_repeated()) {
	if (field->type() == TYPE_MESSAGE) {
	p->Print("$n$_->FromProto(proto.$n$());\n", "n", field->name());
	} else {
	p->Print(
	"static_assert(sizeof($n$_) == sizeof(proto.$n$()), \"size "
	"mismatch\");\n",
	"n", field->name());
	p->Print("$n$_ = static_cast<decltype($n$_)>(proto.$n$());\n", "n",
	field->name());
	}
	} else { // is_repeated()
	p->Print("$n$_.clear();\n", "n", field->name());
	p->Print("for (const auto& field : proto.$n$()) {\n", "n", field->name());
	p->Print(" $n$_.emplace_back();\n", "n", field->name());
	if (field->type() == TYPE_MESSAGE) {
	p->Print(" $n$_.back().FromProto(field);\n", "n", field->name());
	} else {
	p->Print(
	"static_assert(sizeof($n$_.back()) == sizeof(proto.$n$(0)), \"size "
	"mismatch\");\n",
	"n", field->name());
	p->Print(
	" $n$_.back() = static_cast<decltype($n$_)::value_type>(field);\n",
	"n", field->name());
	}
	p->Print("}\n");
	}
	}
	p->Print("unknown_fields_ = proto.unknown_fields();\n");
	p->Outdent();
	p->Print("}\n\n");

	// Genrate the ToProto() method definition.
	p->Print("void $f$::ToProto($p$* proto) const {\n", "f", full_name, "p",
	proto_type);
	p->Indent();
	p->Print("proto->Clear();\n");
	for (int i = 0; i < msg->field_count(); i++) {
	p->Print("\n");
	const FieldDescriptor* field = msg->field(i);
	if (field->options().lazy()) {
	p->Print("proto->mutable_$n$()->ParseFromString($n$_);\n", "n",
	field->name());
	} else if (!field->is_repeated()) {
	if (field->type() == TYPE_MESSAGE) {
	p->Print("$n$_->ToProto(proto->mutable_$n$());\n", "n", field->name());
	} else {
	p->Print(
	"static_assert(sizeof($n$_) == sizeof(proto->$n$()), \"size "
	"mismatch\");\n",
	"n", field->name());
	p->Print("proto->set_$n$(static_cast<decltype(proto->$n$())>($n$_));\n",
	"n", field->name());
	}
	} else { // is_repeated()
	p->Print("for (const auto& it : $n$_) {\n", "n", field->name());
	if (field->type() == TYPE_MESSAGE) {
	p->Print(" auto* entry = proto->add_$n$();\n", "n", field->name());
	p->Print(" it.ToProto(entry);\n");
	} else {
	p->Print(
	" proto->add_$n$(static_cast<decltype(proto->$n$(0))>(it));\n",
	"n", field->name());
	p->Print(
	"static_assert(sizeof(it) == sizeof(proto->$n$(0)), \"size "
	"mismatch\");\n",
	"n", field->name());
	}
	p->Print("}\n");
	}
	}
	p->Print("*(proto->mutable_unknown_fields()) = unknown_fields_;\n");
	p->Outdent();
	p->Print("}\n\n");

	// Recurse into nested types.
	for (int i = 0; i < msg->field_count(); i++) {
	const FieldDescriptor* field = msg->field(i);
	// [lazy=true] field are not recursesd and exposed as raw-strings
	// containing proto-encoded bytes.
	if (field->options().lazy())
	continue;

	if (field->type() == TYPE_MESSAGE &&
	field->message_type()->file() == msg->file()) {
	std::string child_prefix = prefix + msg->name() + "::";
	GenCpp(field->message_type(), p, child_prefix);
	}
	}
	}

	int main(int argc, char** argv) {
	if (argc <= 4) {
	PERFETTO_ELOG(
	"Usage: %s source.proto dir/for/header dir/for/cc include/path",
	argv[0]);
	return 1;
	}
	ProtoToCpp proto_to_cpp(argv[2], argv[3], argv[4]);
	proto_to_cpp.Convert(argv[1]);
	return 0;
	}