// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// Author: kenton@google.com (Kenton Varda)
//  Based on original Protocol Buffers design by
//  Sanjay Ghemawat, Jeff Dean, and others.

#include <google/protobuf/compiler/java/java_file.h>

#include <memory>
#ifndef _SHARED_PTR_H
#include <google/protobuf/stubs/shared_ptr.h>
#endif
#include <set>

#include <google/protobuf/compiler/java/java_context.h>
#include <google/protobuf/compiler/java/java_enum.h>
#include <google/protobuf/compiler/java/java_extension.h>
#include <google/protobuf/compiler/java/java_generator_factory.h>
#include <google/protobuf/compiler/java/java_helpers.h>
#include <google/protobuf/compiler/java/java_message.h>
#include <google/protobuf/compiler/java/java_name_resolver.h>
#include <google/protobuf/compiler/java/java_service.h>
#include <google/protobuf/compiler/java/java_shared_code_generator.h>
#include <google/protobuf/compiler/code_generator.h>
#include <google/protobuf/io/printer.h>
#include <google/protobuf/io/zero_copy_stream.h>
#include <google/protobuf/descriptor.pb.h>
#include <google/protobuf/dynamic_message.h>
#include <google/protobuf/stubs/strutil.h>

namespace google {
namespace protobuf {
namespace compiler {
namespace java {

namespace {

struct FieldDescriptorCompare {
  bool operator ()(const FieldDescriptor* f1, const FieldDescriptor* f2) {
    if(f1 == NULL) {
      return false;
    }
    if(f2 == NULL) {
      return true;
    }
    return f1->full_name() < f2->full_name();
  }
};

typedef std::set<const FieldDescriptor*, FieldDescriptorCompare> FieldDescriptorSet;

// Recursively searches the given message to collect extensions.
// Returns true if all the extensions can be recognized. The extensions will be
// appended in to the extensions parameter.
// Returns false when there are unknown fields, in which case the data in the
// extensions output parameter is not reliable and should be discarded.
bool CollectExtensions(const Message& message,
                       FieldDescriptorSet* extensions) {
  const Reflection* reflection = message.GetReflection();

  // There are unknown fields that could be extensions, thus this call fails.
  if (reflection->GetUnknownFields(message).field_count() > 0) return false;

  vector<const FieldDescriptor*> fields;
  reflection->ListFields(message, &fields);

  for (int i = 0; i < fields.size(); i++) {
    if (fields[i]->is_extension()) extensions->insert(fields[i]);

    if (GetJavaType(fields[i]) == JAVATYPE_MESSAGE) {
      if (fields[i]->is_repeated()) {
        int size = reflection->FieldSize(message, fields[i]);
        for (int j = 0; j < size; j++) {
          const Message& sub_message =
            reflection->GetRepeatedMessage(message, fields[i], j);
          if (!CollectExtensions(sub_message, extensions)) return false;
        }
      } else {
        const Message& sub_message = reflection->GetMessage(message, fields[i]);
        if (!CollectExtensions(sub_message, extensions)) return false;
      }
    }
  }

  return true;
}

// Finds all extensions in the given message and its sub-messages.  If the
// message contains unknown fields (which could be extensions), then those
// extensions are defined in alternate_pool.
// The message will be converted to a DynamicMessage backed by alternate_pool
// in order to handle this case.
void CollectExtensions(const FileDescriptorProto& file_proto,
                       const DescriptorPool& alternate_pool,
                       FieldDescriptorSet* extensions,
                       const string& file_data) {
  if (!CollectExtensions(file_proto, extensions)) {
    // There are unknown fields in the file_proto, which are probably
    // extensions. We need to parse the data into a dynamic message based on the
    // builder-pool to find out all extensions.
    const Descriptor* file_proto_desc = alternate_pool.FindMessageTypeByName(
        file_proto.GetDescriptor()->full_name());
    GOOGLE_CHECK(file_proto_desc)
        << "Find unknown fields in FileDescriptorProto when building "
        << file_proto.name()
        << ". It's likely that those fields are custom options, however, "
           "descriptor.proto is not in the transitive dependencies. "
           "This normally should not happen. Please report a bug.";
    DynamicMessageFactory factory;
    google::protobuf::scoped_ptr<Message> dynamic_file_proto(
        factory.GetPrototype(file_proto_desc)->New());
    GOOGLE_CHECK(dynamic_file_proto.get() != NULL);
    GOOGLE_CHECK(dynamic_file_proto->ParseFromString(file_data));

    // Collect the extensions again from the dynamic message. There should be no
    // more unknown fields this time, i.e. all the custom options should be
    // parsed as extensions now.
    extensions->clear();
    GOOGLE_CHECK(CollectExtensions(*dynamic_file_proto, extensions))
        << "Find unknown fields in FileDescriptorProto when building "
        << file_proto.name()
        << ". It's likely that those fields are custom options, however, "
           "those options cannot be recognized in the builder pool. "
           "This normally should not happen. Please report a bug.";
  }
}

// Compare two field descriptors, returning true if the first should come
// before the second.
bool CompareFieldsByName(const FieldDescriptor *a, const FieldDescriptor *b) {
  return a->full_name() < b->full_name();
}

// Our static initialization methods can become very, very large.
// So large that if we aren't careful we end up blowing the JVM's
// 64K bytes of bytecode/method. Fortunately, since these static
// methods are executed only once near the beginning of a program,
// there's usually plenty of stack space available and we can
// extend our methods by simply chaining them to another method
// with a tail call. This inserts the sequence call-next-method,
// end this one, begin-next-method as needed.
void MaybeRestartJavaMethod(io::Printer* printer,
                            int *bytecode_estimate,
                            int *method_num,
                            const char *chain_statement,
                            const char *method_decl) {
  // The goal here is to stay under 64K bytes of jvm bytecode/method,
  // since otherwise we hit a hardcoded limit in the jvm and javac will
  // then fail with the error "code too large". This limit lets our
  // estimates be off by a factor of two and still we're okay.
  static const int bytesPerMethod = 1<<15;  // aka 32K

  if ((*bytecode_estimate) > bytesPerMethod) {
    ++(*method_num);
    printer->Print(chain_statement, "method_num", SimpleItoa(*method_num));
    printer->Outdent();
    printer->Print("}\n");
    printer->Print(method_decl, "method_num", SimpleItoa(*method_num));
    printer->Indent();
    *bytecode_estimate = 0;
  }
}


}  // namespace

FileGenerator::FileGenerator(const FileDescriptor* file, bool immutable_api)
    : file_(file),
      java_package_(FileJavaPackage(file, immutable_api)),
      message_generators_(
          new google::protobuf::scoped_ptr<MessageGenerator>[file->message_type_count()]),
      extension_generators_(
          new google::protobuf::scoped_ptr<ExtensionGenerator>[file->extension_count()]),
      context_(new Context(file)),
      name_resolver_(context_->GetNameResolver()),
      immutable_api_(immutable_api) {
  classname_ = name_resolver_->GetFileClassName(file, immutable_api);
  generator_factory_.reset(
      new ImmutableGeneratorFactory(context_.get()));
  for (int i = 0; i < file_->message_type_count(); ++i) {
    message_generators_[i].reset(
        generator_factory_->NewMessageGenerator(file_->message_type(i)));
  }
  for (int i = 0; i < file_->extension_count(); ++i) {
    extension_generators_[i].reset(
        generator_factory_->NewExtensionGenerator(file_->extension(i)));
  }
}

FileGenerator::~FileGenerator() {}

bool FileGenerator::Validate(string* error) {
  // Check that no class name matches the file's class name.  This is a common
  // problem that leads to Java compile errors that can be hard to understand.
  // It's especially bad when using the java_multiple_files, since we would
  // end up overwriting the outer class with one of the inner ones.
  if (name_resolver_->HasConflictingClassName(file_, classname_)) {
    error->assign(file_->name());
    error->append(
      ": Cannot generate Java output because the file's outer class name, \"");
    error->append(classname_);
    error->append(
      "\", matches the name of one of the types declared inside it.  "
      "Please either rename the type or use the java_outer_classname "
      "option to specify a different outer class name for the .proto file.");
    return false;
  }
  return true;
}

void FileGenerator::Generate(io::Printer* printer) {
  // We don't import anything because we refer to all classes by their
  // fully-qualified names in the generated source.
  printer->Print(
    "// Generated by the protocol buffer compiler.  DO NOT EDIT!\n"
    "// source: $filename$\n"
    "\n",
    "filename", file_->name());
  if (!java_package_.empty()) {
    printer->Print(
      "package $package$;\n"
      "\n",
      "package", java_package_);
  }
  printer->Print(
    "public final class $classname$ {\n"
    "  private $classname$() {}\n",
    "classname", classname_);
  printer->Indent();

  // -----------------------------------------------------------------

  printer->Print(
    "public static void registerAllExtensions(\n"
    "    com.google.protobuf.ExtensionRegistry$lite$ registry) {\n",
    "lite", HasDescriptorMethods(file_) ? "" : "Lite");

  printer->Indent();

  for (int i = 0; i < file_->extension_count(); i++) {
    extension_generators_[i]->GenerateRegistrationCode(printer);
  }

  for (int i = 0; i < file_->message_type_count(); i++) {
    message_generators_[i]->GenerateExtensionRegistrationCode(printer);
  }

  printer->Outdent();
  printer->Print(
    "}\n");

  // -----------------------------------------------------------------

  if (!MultipleJavaFiles(file_, immutable_api_)) {
    for (int i = 0; i < file_->enum_type_count(); i++) {
      EnumGenerator(file_->enum_type(i), immutable_api_, context_.get())
          .Generate(printer);
    }
    for (int i = 0; i < file_->message_type_count(); i++) {
      message_generators_[i]->GenerateInterface(printer);
      message_generators_[i]->Generate(printer);
    }
    if (HasGenericServices(file_)) {
      for (int i = 0; i < file_->service_count(); i++) {
        google::protobuf::scoped_ptr<ServiceGenerator> generator(
            generator_factory_->NewServiceGenerator(file_->service(i)));
        generator->Generate(printer);
      }
    }
  }

  // Extensions must be generated in the outer class since they are values,
  // not classes.
  for (int i = 0; i < file_->extension_count(); i++) {
    extension_generators_[i]->Generate(printer);
  }

  // Static variables.
  for (int i = 0; i < file_->message_type_count(); i++) {
    message_generators_[i]->GenerateStaticVariables(printer);
  }

  printer->Print("\n");

  if (HasDescriptorMethods(file_)) {
    if (immutable_api_) {
      GenerateDescriptorInitializationCodeForImmutable(printer);
    } else {
      GenerateDescriptorInitializationCodeForMutable(printer);
    }
  } else {
    printer->Print(
      "static {\n");
    printer->Indent();
    int bytecode_estimate = 0;
    int method_num = 0;

    for (int i = 0; i < file_->message_type_count(); i++) {
      bytecode_estimate += message_generators_[i]->GenerateStaticVariableInitializers(printer);
      MaybeRestartJavaMethod(
        printer,
        &bytecode_estimate, &method_num,
        "_clinit_autosplit_$method_num$();\n",
        "private static void _clinit_autosplit_$method_num$() {\n");
    }

    printer->Outdent();
    printer->Print(
      "}\n");
  }

  printer->Print(
    "\n"
    "// @@protoc_insertion_point(outer_class_scope)\n");

  printer->Outdent();
  printer->Print("}\n");
}

void FileGenerator::GenerateDescriptorInitializationCodeForImmutable(
    io::Printer* printer) {
  printer->Print(
    "public static com.google.protobuf.Descriptors.FileDescriptor\n"
    "    getDescriptor() {\n"
    "  return descriptor;\n"
    "}\n"
    "private static com.google.protobuf.Descriptors.FileDescriptor\n"
    "    descriptor;\n"
    "static {\n");
  printer->Indent();

  SharedCodeGenerator shared_code_generator(file_);
  shared_code_generator.GenerateDescriptors(printer);

  int bytecode_estimate = 0;
  int method_num = 0;

  for (int i = 0; i < file_->message_type_count(); i++) {
    bytecode_estimate += message_generators_[i]->GenerateStaticVariableInitializers(printer);
    MaybeRestartJavaMethod(
      printer,
      &bytecode_estimate, &method_num,
      "_clinit_autosplit_dinit_$method_num$();\n",
      "private static void _clinit_autosplit_dinit_$method_num$() {\n");
  }
  for (int i = 0; i < file_->extension_count(); i++) {
    bytecode_estimate += extension_generators_[i]->GenerateNonNestedInitializationCode(printer);
    MaybeRestartJavaMethod(
      printer,
      &bytecode_estimate, &method_num,
      "_clinit_autosplit_dinit_$method_num$();\n",
      "private static void _clinit_autosplit_dinit_$method_num$() {\n");
  }

  // Proto compiler builds a DescriptorPool, which holds all the descriptors to
  // generate, when processing the ".proto" files. We call this DescriptorPool
  // the parsed pool (a.k.a. file_->pool()).
  //
  // Note that when users try to extend the (.*)DescriptorProto in their
  // ".proto" files, it does not affect the pre-built FileDescriptorProto class
  // in proto compiler. When we put the descriptor data in the file_proto, those
  // extensions become unknown fields.
  //
  // Now we need to find out all the extension value to the (.*)DescriptorProto
  // in the file_proto message, and prepare an ExtensionRegistry to return.
  //
  // To find those extensions, we need to parse the data into a dynamic message
  // of the FileDescriptor based on the builder-pool, then we can use
  // reflections to find all extension fields
  FileDescriptorProto file_proto;
  file_->CopyTo(&file_proto);
  string file_data;
  file_proto.SerializeToString(&file_data);
  FieldDescriptorSet extensions;
  CollectExtensions(file_proto, *file_->pool(), &extensions, file_data);

  if (extensions.size() > 0) {
    // Must construct an ExtensionRegistry containing all existing extensions
    // and use it to parse the descriptor data again to recognize extensions.
    printer->Print(
      "com.google.protobuf.ExtensionRegistry registry =\n"
      "    com.google.protobuf.ExtensionRegistry.newInstance();\n");
    FieldDescriptorSet::iterator it;
    for (it = extensions.begin(); it != extensions.end(); it++) {
      google::protobuf::scoped_ptr<ExtensionGenerator> generator(
          generator_factory_->NewExtensionGenerator(*it));
      bytecode_estimate += generator->GenerateRegistrationCode(printer);
      MaybeRestartJavaMethod(
        printer,
        &bytecode_estimate, &method_num,
        "_clinit_autosplit_dinit_$method_num$(registry);\n",
        "private static void _clinit_autosplit_dinit_$method_num$(\n"
        "    com.google.protobuf.ExtensionRegistry registry) {\n");
    }
    printer->Print(
      "com.google.protobuf.Descriptors.FileDescriptor\n"
      "    .internalUpdateFileDescriptor(descriptor, registry);\n");
  }

  // Force descriptor initialization of all dependencies.
  for (int i = 0; i < file_->dependency_count(); i++) {
    if (ShouldIncludeDependency(file_->dependency(i), true)) {
      string dependency =
          name_resolver_->GetImmutableClassName(file_->dependency(i));
      printer->Print(
        "$dependency$.getDescriptor();\n",
        "dependency", dependency);
    }
  }

  printer->Outdent();
  printer->Print(
    "}\n");
}

void FileGenerator::GenerateDescriptorInitializationCodeForMutable(io::Printer* printer) {
  printer->Print(
    "public static com.google.protobuf.Descriptors.FileDescriptor\n"
    "    getDescriptor() {\n"
    "  return descriptor;\n"
    "}\n"
    "private static com.google.protobuf.Descriptors.FileDescriptor\n"
    "    descriptor;\n"
    "static {\n");
  printer->Indent();

  printer->Print(
    "descriptor = $immutable_package$.$descriptor_classname$.descriptor;\n",
    "immutable_package", FileJavaPackage(file_, true),
    "descriptor_classname", name_resolver_->GetDescriptorClassName(file_));

  for (int i = 0; i < file_->message_type_count(); i++) {
    message_generators_[i]->GenerateStaticVariableInitializers(printer);
  }
  for (int i = 0; i < file_->extension_count(); i++) {
    extension_generators_[i]->GenerateNonNestedInitializationCode(printer);
  }

  // Check if custom options exist. If any, try to load immutable classes since
  // custom options are only represented with immutable messages.
  FileDescriptorProto file_proto;
  file_->CopyTo(&file_proto);
  string file_data;
  file_proto.SerializeToString(&file_data);
  FieldDescriptorSet extensions;
  CollectExtensions(file_proto, *file_->pool(), &extensions, file_data);

  if (extensions.size() > 0) {
    // Try to load immutable messages' outer class. Its initialization code
    // will take care of interpreting custom options.
    printer->Print(
      "try {\n"
      // Note that we have to load the immutable class dynamically here as
      // we want the mutable code to be independent from the immutable code
      // at compile time. It is required to implement dual-compile for
      // mutable and immutable API in blaze.
      "  java.lang.Class immutableClass = java.lang.Class.forName(\n"
      "      \"$immutable_classname$\");\n"
      "} catch (java.lang.ClassNotFoundException e) {\n"
      // The immutable class can not be found. Custom options are left
      // as unknown fields.
      // TODO(xiaofeng): inform the user with a warning?
      "}\n",
      "immutable_classname", name_resolver_->GetImmutableClassName(file_));
  }

  // Force descriptor initialization of all dependencies.
  for (int i = 0; i < file_->dependency_count(); i++) {
    if (ShouldIncludeDependency(file_->dependency(i), false)) {
      string dependency = name_resolver_->GetMutableClassName(
          file_->dependency(i));
      printer->Print(
        "$dependency$.getDescriptor();\n",
        "dependency", dependency);
    }
  }

  printer->Outdent();
  printer->Print(
    "}\n");
}

template<typename GeneratorClass, typename DescriptorClass>
static void GenerateSibling(const string& package_dir,
                            const string& java_package,
                            const DescriptorClass* descriptor,
                            GeneratorContext* context,
                            vector<string>* file_list,
                            const string& name_suffix,
                            GeneratorClass* generator,
                            void (GeneratorClass::*pfn)(io::Printer* printer)) {
  string filename = package_dir + descriptor->name() + name_suffix + ".java";
  file_list->push_back(filename);

  google::protobuf::scoped_ptr<io::ZeroCopyOutputStream> output(context->Open(filename));
  io::Printer printer(output.get(), '$');

  printer.Print(
    "// Generated by the protocol buffer compiler.  DO NOT EDIT!\n"
    "// source: $filename$\n"
    "\n",
    "filename", descriptor->file()->name());
  if (!java_package.empty()) {
    printer.Print(
      "package $package$;\n"
      "\n",
      "package", java_package);
  }

  (generator->*pfn)(&printer);
}

void FileGenerator::GenerateSiblings(const string& package_dir,
                                     GeneratorContext* context,
                                     vector<string>* file_list) {
  if (MultipleJavaFiles(file_, immutable_api_)) {
    for (int i = 0; i < file_->enum_type_count(); i++) {
      EnumGenerator generator(file_->enum_type(i), immutable_api_,
                              context_.get());
      GenerateSibling<EnumGenerator>(package_dir, java_package_,
                                     file_->enum_type(i),
                                     context, file_list, "",
                                     &generator,
                                     &EnumGenerator::Generate);
    }
    for (int i = 0; i < file_->message_type_count(); i++) {
      if (immutable_api_) {
        GenerateSibling<MessageGenerator>(package_dir, java_package_,
                                          file_->message_type(i),
                                          context, file_list,
                                          "OrBuilder",
                                          message_generators_[i].get(),
                                          &MessageGenerator::GenerateInterface);
      }
      GenerateSibling<MessageGenerator>(package_dir, java_package_,
                                        file_->message_type(i),
                                        context, file_list, "",
                                        message_generators_[i].get(),
                                        &MessageGenerator::Generate);
    }
    if (HasGenericServices(file_)) {
      for (int i = 0; i < file_->service_count(); i++) {
        google::protobuf::scoped_ptr<ServiceGenerator> generator(
            generator_factory_->NewServiceGenerator(file_->service(i)));
        GenerateSibling<ServiceGenerator>(package_dir, java_package_,
                                          file_->service(i),
                                          context, file_list, "",
                                          generator.get(),
                                          &ServiceGenerator::Generate);
      }
    }
  }
}

bool FileGenerator::ShouldIncludeDependency(
    const FileDescriptor* descriptor, bool immutable_api) {
  return true;
}

}  // namespace java
}  // namespace compiler
}  // namespace protobuf
}  // namespace google
