generate_java.cpp

/*
 * Copyright (C) 2016, 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 "generate_java.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <map>
#include <memory>
#include <sstream>

#include <android-base/stringprintf.h>

#include "aidl_to_java.h"
#include "code_writer.h"
#include "logging.h"

using std::unique_ptr;
using ::android::aidl::java::Variable;
using std::string;

namespace {
using android::aidl::java::CodeGeneratorContext;
using android::aidl::java::ConstantValueDecorator;

void GenerateToString(CodeWriter& out, const AidlStructuredParcelable& parcel,
                      const AidlTypenames& typenames) {
  out << "@Override\n";
  out << "public String toString() {\n";
  out.Indent();
  out << "java.util.StringJoiner _aidl_sj = new java.util.StringJoiner(";
  out << "\", \", \"{\", \"}\");\n";
  for (const auto& field : parcel.GetFields()) {
    CodeGeneratorContext ctx{
        .writer = out,
        .typenames = typenames,
        .type = field->GetType(),
        .var = field->GetName(),
    };
    out << "_aidl_sj.add(\"" << field->GetName() << ": \" + (";
    ToStringFor(ctx);
    out << "));\n";
  }
  out << "return \"" << parcel.GetCanonicalName() << "\" + _aidl_sj.toString()  ;\n";
  out.Dedent();
  out << "}\n";
}

template <typename ParcelableType>
void GenerateDerivedMethods(CodeWriter& out, const ParcelableType& parcel,
                            const AidlTypenames& typenames) {
  if (auto java_derive = parcel.JavaDerive(); java_derive) {
    auto synthetic_methods = java_derive->AnnotationParams(ConstantValueDecorator);
    for (const auto& [method_name, generate] : synthetic_methods) {
      if (generate == "true") {
        if (method_name == "toString") {
          GenerateToString(out, parcel, typenames);
        }
      }
    }
  }
}
}  // namespace

namespace android {
namespace aidl {
namespace java {

bool generate_java_interface(const string& filename, const AidlInterface* iface,
                             const AidlTypenames& typenames, const IoDelegate& io_delegate,
                             const Options& options) {
  auto cl = generate_binder_interface_class(iface, typenames, options);

  std::unique_ptr<Document> document =
      std::make_unique<Document>("" /* no comment */, iface->GetPackage(), std::move(cl));

  CodeWriterPtr code_writer = io_delegate.GetCodeWriter(filename);
  document->Write(code_writer.get());

  return true;
}

bool generate_java_parcel(const std::string& filename, const AidlStructuredParcelable* parcel,
                          const AidlTypenames& typenames, const IoDelegate& io_delegate) {
  auto cl = generate_parcel_class(parcel, typenames);

  std::unique_ptr<Document> document =
      std::make_unique<Document>("" /* no comment */, parcel->GetPackage(), std::move(cl));

  CodeWriterPtr code_writer = io_delegate.GetCodeWriter(filename);
  document->Write(code_writer.get());

  return true;
}

bool generate_java_enum_declaration(const std::string& filename,
                                    const AidlEnumDeclaration* enum_decl,
                                    const AidlTypenames& typenames, const IoDelegate& io_delegate) {
  CodeWriterPtr code_writer = io_delegate.GetCodeWriter(filename);
  generate_enum(code_writer, enum_decl, typenames);
  return true;
}

bool generate_java(const std::string& filename, const AidlDefinedType* defined_type,
                   const AidlTypenames& typenames, const IoDelegate& io_delegate,
                   const Options& options) {
  if (const AidlStructuredParcelable* parcelable = defined_type->AsStructuredParcelable();
      parcelable != nullptr) {
    return generate_java_parcel(filename, parcelable, typenames, io_delegate);
  }

  if (const AidlEnumDeclaration* enum_decl = defined_type->AsEnumDeclaration();
      enum_decl != nullptr) {
    return generate_java_enum_declaration(filename, enum_decl, typenames, io_delegate);
  }

  if (const AidlInterface* interface = defined_type->AsInterface(); interface != nullptr) {
    return generate_java_interface(filename, interface, typenames, io_delegate, options);
  }

  CHECK(false) << "Unrecognized type sent for java generation.";
  return false;
}

std::unique_ptr<android::aidl::java::Class> generate_parcel_class(
    const AidlStructuredParcelable* parcel, const AidlTypenames& typenames) {
  auto parcel_class = std::make_unique<Class>();
  parcel_class->comment = parcel->GetComments();
  parcel_class->modifiers = PUBLIC;
  parcel_class->what = Class::CLASS;
  parcel_class->type = parcel->GetCanonicalName();
  parcel_class->interfaces.push_back("android.os.Parcelable");
  parcel_class->annotations = generate_java_annotations(*parcel);

  for (const auto& variable : parcel->GetFields()) {
    std::ostringstream out;
    out << variable->GetType().GetComments() << "\n";
    for (const auto& a : generate_java_annotations(variable->GetType())) {
      out << a << "\n";
    }
    out << "public " << JavaSignatureOf(variable->GetType(), typenames) << " "
        << variable->GetName();
    if (variable->GetDefaultValue()) {
      out << " = " << variable->ValueString(ConstantValueDecorator);
    }
    out << ";\n";
    parcel_class->elements.push_back(std::make_shared<LiteralClassElement>(out.str()));
  }

  std::ostringstream out;
  out << "public static final android.os.Parcelable.Creator<" << parcel->GetName() << "> CREATOR = "
      << "new android.os.Parcelable.Creator<" << parcel->GetName() << ">() {\n";
  out << "  @Override\n";
  out << "  public " << parcel->GetName()
      << " createFromParcel(android.os.Parcel _aidl_source) {\n";
  out << "    " << parcel->GetName() << " _aidl_out = new " << parcel->GetName() << "();\n";
  out << "    _aidl_out.readFromParcel(_aidl_source);\n";
  out << "    return _aidl_out;\n";
  out << "  }\n";
  out << "  @Override\n";
  out << "  public " << parcel->GetName() << "[] newArray(int _aidl_size) {\n";
  out << "    return new " << parcel->GetName() << "[_aidl_size];\n";
  out << "  }\n";
  out << "};\n";
  parcel_class->elements.push_back(std::make_shared<LiteralClassElement>(out.str()));

  auto flag_variable = std::make_shared<Variable>("int", "_aidl_flag");
  auto parcel_variable = std::make_shared<Variable>("android.os.Parcel", "_aidl_parcel");

  auto write_method = std::make_shared<Method>();
  write_method->modifiers = PUBLIC | OVERRIDE | FINAL;
  write_method->returnType = "void";
  write_method->name = "writeToParcel";
  write_method->parameters.push_back(parcel_variable);
  write_method->parameters.push_back(flag_variable);
  write_method->statements = std::make_shared<StatementBlock>();

  out.str("");
  out << "int _aidl_start_pos = _aidl_parcel.dataPosition();\n"
      << "_aidl_parcel.writeInt(0);\n";
  write_method->statements->Add(std::make_shared<LiteralStatement>(out.str()));

  for (const auto& field : parcel->GetFields()) {
    string code;
    CodeWriterPtr writer = CodeWriter::ForString(&code);
    CodeGeneratorContext context{
        .writer = *(writer.get()),
        .typenames = typenames,
        .type = field->GetType(),
        .parcel = parcel_variable->name,
        .var = field->GetName(),
        .is_return_value = false,
    };
    WriteToParcelFor(context);
    writer->Close();
    write_method->statements->Add(std::make_shared<LiteralStatement>(code));
  }

  out.str("");
  out << "int _aidl_end_pos = _aidl_parcel.dataPosition();\n"
      << "_aidl_parcel.setDataPosition(_aidl_start_pos);\n"
      << "_aidl_parcel.writeInt(_aidl_end_pos - _aidl_start_pos);\n"
      << "_aidl_parcel.setDataPosition(_aidl_end_pos);\n";

  write_method->statements->Add(std::make_shared<LiteralStatement>(out.str()));

  parcel_class->elements.push_back(write_method);

  auto read_method = std::make_shared<Method>();
  read_method->modifiers = PUBLIC | FINAL;
  read_method->returnType = "void";
  read_method->name = "readFromParcel";
  read_method->parameters.push_back(parcel_variable);
  read_method->statements = std::make_shared<StatementBlock>();

  out.str("");
  out << "int _aidl_start_pos = _aidl_parcel.dataPosition();\n"
      << "int _aidl_parcelable_size = _aidl_parcel.readInt();\n"
      << "if (_aidl_parcelable_size < 0) return;\n"
      << "try {\n";

  read_method->statements->Add(std::make_shared<LiteralStatement>(out.str()));

  out.str("");
  out << "  if (_aidl_parcel.dataPosition() - _aidl_start_pos >= _aidl_parcelable_size) return;\n";

  std::shared_ptr<LiteralStatement> sizeCheck = nullptr;
  // keep this across different fields in order to create the classloader
  // at most once.
  bool is_classloader_created = false;
  for (const auto& field : parcel->GetFields()) {
    string code;
    CodeWriterPtr writer = CodeWriter::ForString(&code);
    CodeGeneratorContext context{
        .writer = *(writer.get()),
        .typenames = typenames,
        .type = field->GetType(),
        .parcel = parcel_variable->name,
        .var = field->GetName(),
        .is_classloader_created = &is_classloader_created,
    };
    context.writer.Indent();
    CreateFromParcelFor(context);
    writer->Close();
    read_method->statements->Add(std::make_shared<LiteralStatement>(code));
    if (!sizeCheck) sizeCheck = std::make_shared<LiteralStatement>(out.str());
    read_method->statements->Add(sizeCheck);
  }

  out.str("");
  out << "} finally {\n"
      << "  _aidl_parcel.setDataPosition(_aidl_start_pos + _aidl_parcelable_size);\n"
      << "}\n";

  read_method->statements->Add(std::make_shared<LiteralStatement>(out.str()));

  parcel_class->elements.push_back(read_method);

  auto method = CodeWriter::RunWith(GenerateDerivedMethods, *parcel, typenames);
  parcel_class->elements.push_back(std::make_shared<LiteralClassElement>(method));

  auto describe_contents_method = std::make_shared<Method>();
  describe_contents_method->modifiers = PUBLIC | OVERRIDE;
  describe_contents_method->returnType = "int";
  describe_contents_method->name = "describeContents";
  describe_contents_method->statements = std::make_shared<StatementBlock>();
  describe_contents_method->statements->Add(std::make_shared<LiteralStatement>("return 0;\n"));
  parcel_class->elements.push_back(describe_contents_method);

  return parcel_class;
}

void generate_enum(const CodeWriterPtr& code_writer, const AidlEnumDeclaration* enum_decl,
                   const AidlTypenames& typenames) {
  code_writer->Write(
      "/*\n"
      " * This file is auto-generated.  DO NOT MODIFY.\n"
      " */\n");

  code_writer->Write("package %s;\n", enum_decl->GetPackage().c_str());
  code_writer->Write("%s\n", enum_decl->GetComments().c_str());
  for (const std::string& annotation : generate_java_annotations(*enum_decl)) {
    code_writer->Write("%s", annotation.c_str());
  }
  code_writer->Write("public @interface %s {\n", enum_decl->GetName().c_str());
  code_writer->Indent();
  for (const auto& enumerator : enum_decl->GetEnumerators()) {
    code_writer->Write("%s", enumerator->GetComments().c_str());
    code_writer->Write(
        "public static final %s %s = %s;\n",
        JavaSignatureOf(enum_decl->GetBackingType(), typenames).c_str(),
        enumerator->GetName().c_str(),
        enumerator->ValueString(enum_decl->GetBackingType(), ConstantValueDecorator).c_str());
  }
  code_writer->Dedent();
  code_writer->Write("}\n");
}

std::string dump_location(const AidlNode& method) {
  return method.PrintLocation();
}

std::string generate_java_unsupportedappusage_parameters(const AidlAnnotation& a) {
  const std::map<std::string, std::string> params = a.AnnotationParams(ConstantValueDecorator);
  std::vector<string> parameters_decl;
  for (const auto& name_and_param : params) {
    const std::string& param_name = name_and_param.first;
    const std::string& param_value = name_and_param.second;
    parameters_decl.push_back(param_name + " = " + param_value);
  }
  parameters_decl.push_back("overrideSourcePosition=\"" + dump_location(a) + "\"");
  return "(" + base::Join(parameters_decl, ", ") + ")";
}

std::vector<std::string> generate_java_annotations(const AidlAnnotatable& a) {
  std::vector<std::string> result;
  const AidlAnnotation* unsupported_app_usage = a.UnsupportedAppUsage();
  if (a.IsHide()) {
    result.emplace_back("@android.annotation.Hide");
  }
  if (unsupported_app_usage != nullptr) {
    result.emplace_back("@android.compat.annotation.UnsupportedAppUsage" +
                        generate_java_unsupportedappusage_parameters(*unsupported_app_usage));
  }
  return result;
}

}  // namespace java
}  // namespace aidl
}  // namespace android