[ios Mojo] iOS facade class for Mojo API.

ios/web/webui/mojo_facade.mm

Index: ios/web/webui/mojo_facade.mm
diff --git a/ios/web/webui/mojo_facade.mm b/ios/web/webui/mojo_facade.mm
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+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "ios/web/webui/mojo_facade.h"
+
+#import <Foundation/Foundation.h>
+
+#include "base/ios/block_types.h"
+#include "base/json/json_reader.h"
+#include "base/json/json_writer.h"
+#include "base/mac/bind_objc_block.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/values.h"
+#import "ios/web/public/web_state/js/crw_js_injection_evaluator.h"
+#include "ios/web/public/web_thread.h"
+#include "mojo/public/cpp/system/core.h"
+#include "services/shell/public/interfaces/interface_provider.mojom.h"
+
+namespace web {
+
+namespace {
+
+// Wraps an integer into |base::Value| as |TYPE_INTEGER|.
+template <typename IntegerT>
+std::unique_ptr<base::Value> ValueFromInteger(IntegerT handle) {
+  return std::unique_ptr<base::Value>(
+      new base::FundamentalValue(static_cast<int>(handle)));
+}
+
+}  // namespace
+
+MojoFacade::MojoFacade(shell::mojom::InterfaceProvider* interface_provider,
+                       id<CRWJSInjectionEvaluator> script_evaluator)
+    : interface_provider_(interface_provider),
+      script_evaluator_(script_evaluator) {
+  DCHECK_CURRENTLY_ON(WebThread::UI);
+  DCHECK(interface_provider_);
+  DCHECK(script_evaluator_);
+}
+
+MojoFacade::~MojoFacade() {
+  DCHECK_CURRENTLY_ON(WebThread::UI);
+}
+
+std::string MojoFacade::HandleMojoMessage(
+    const std::string& mojo_message_as_json) {
+  DCHECK_CURRENTLY_ON(WebThread::UI);
+  std::string name;
+  std::unique_ptr<base::DictionaryValue> args;
+  GetMessageNameAndArguments(mojo_message_as_json, &name, &args);
+
+  std::unique_ptr<base::Value> result;
+  if (name == "service_provider.connectToService") {
+    result = HandleServiceProviderConnectToService(args.get());
+  } else if (name == "core.close") {
+    result = HandleCoreClose(args.get());
+  } else if (name == "core.createMessagePipe") {
+    result = HandleCoreCreateMessagePipe(args.get());
+  } else if (name == "core.writeMessage") {
+    result = HandleCoreWriteMessage(args.get());
+  } else if (name == "core.readMessage") {
+    result = HandleCoreReadMessage(args.get());
+  } else if (name == "support.watch") {
+    result = HandleSupportWatch(args.get());
+  } else if (name == "support.cancelWatch") {
+    result = HandleSupportCancelWatch(args.get());
+  }
+
+  if (!result) {
+    return "";
+  }
+
+  std::string json_result;
+  base::JSONWriter::Write(*result, &json_result);
+  return json_result;
+}
+
+void MojoFacade::GetMessageNameAndArguments(
+    const std::string& mojo_message_as_json,
+    std::string* out_name,
+    std::unique_ptr<base::DictionaryValue>* out_args) {
+  int error_code = 0;
+  std::string error_message;
+  std::unique_ptr<base::Value> mojo_message_as_value(
+      base::JSONReader::ReadAndReturnError(mojo_message_as_json, false,
+                                           &error_code, &error_message));
+  CHECK(!error_code);
+  base::DictionaryValue* mojo_message = nullptr;
+  CHECK(mojo_message_as_value->GetAsDictionary(&mojo_message));
+
+  std::string name;
+  CHECK(mojo_message->GetString("name", &name));
+
+  base::DictionaryValue* args = nullptr;
+  CHECK(mojo_message->GetDictionary("args", &args));
+
+  *out_name = name;
+  *out_args = args->CreateDeepCopy();
+}
+
+std::unique_ptr<base::Value> MojoFacade::HandleServiceProviderConnectToService(
+    const base::DictionaryValue* args) {
+  const base::Value* service_name_as_value = nullptr;
+  CHECK(args->Get("serviceName", &service_name_as_value));
+
+  // By design service_provider.connectToService either succeeds or crashes, so
+  // check if service name is a valid string is intentionally omitted.
+  std::string service_name_as_string;
+  service_name_as_value->GetAsString(&service_name_as_string);
+
+  mojo::MessagePipe pipe;
+  interface_provider_->GetInterface(mojo::String::From(service_name_as_string),
+                                    std::move(pipe.handle0));
+
+  return ValueFromInteger(pipe.handle1.release().value());
+}
+
+std::unique_ptr<base::Value> MojoFacade::HandleCoreClose(
+    const base::DictionaryValue* args) {
+  int handle = 0;
+  CHECK(args->GetInteger("handle", &handle));
+
+  mojo::Handle(handle).Close();
+
+  return ValueFromInteger(MOJO_RESULT_OK);
+}
+
+std::unique_ptr<base::Value> MojoFacade::HandleCoreCreateMessagePipe(
+    base::DictionaryValue* args) {
+  const base::Value* options_as_value = nullptr;
+  CHECK(args->Get("optionsDict", &options_as_value));
+
+  if (options_as_value->IsType(base::Value::TYPE_DICTIONARY)) {
+    // There are no options defined for CreateMessagePipe yet.
+    const base::DictionaryValue* options_as_dict;
+    options_as_value->GetAsDictionary(&options_as_dict);
+    CHECK(options_as_dict->empty());
+  }
+
+  CHECK(options_as_value->IsType(base::Value::TYPE_NULL));
+
+  mojo::MessagePipe message_pipe;
+  std::unique_ptr<base::DictionaryValue> result(new base::DictionaryValue);
+  result->SetInteger("handle0", message_pipe.handle0.release().value());
+  result->SetInteger("handle1", message_pipe.handle1.release().value());
+  return std::unique_ptr<base::Value>(result.release());
+}
+
+std::unique_ptr<base::Value> MojoFacade::HandleCoreWriteMessage(
+    base::DictionaryValue* args) {
+  int handle = 0;
+  CHECK(args->GetInteger("handle", &handle));
+
+  base::ListValue* handles_list = nullptr;
+  CHECK(args->GetList("handles", &handles_list));
+
+  base::DictionaryValue* buffer = nullptr;
+  CHECK(args->GetDictionary("buffer", &buffer));
+
+  const base::Value* flags_as_value = nullptr;
+  CHECK(args->Get("flags", &flags_as_value));
+
+  int flags = MOJO_WRITE_MESSAGE_FLAG_NONE;
+  if (!flags_as_value->GetAsInteger(&flags)) {
+    flags = MOJO_WRITE_MESSAGE_FLAG_NONE;
+  }
+
+  std::vector<MojoHandle> handles(handles_list->GetSize());
+  for (size_t i = 0; i < handles_list->GetSize(); i++) {
+    int one_handle = 0;
+    handles_list->GetInteger(i, &one_handle);
+    handles[i] = one_handle;
+  }
+
+  std::vector<uint8_t> bytes(buffer->size());
+  for (size_t i = 0; i < buffer->size(); i++) {
+    int one_byte = 0;
+    buffer->GetInteger(base::IntToString(i), &one_byte);
+    bytes[i] = one_byte;
+  }
+
+  mojo::MessagePipeHandle message_pipe(static_cast<MojoHandle>(handle));
+  MojoResult result =
+      mojo::WriteMessageRaw(message_pipe, bytes.data(), bytes.size(),
+                            handles.data(), handles.size(), flags);
+
+  return ValueFromInteger(result);
+}
+
+std::unique_ptr<base::Value> MojoFacade::HandleCoreReadMessage(
+    const base::DictionaryValue* args) {
+  const base::Value* handle_as_value = nullptr;
+  CHECK(args->Get("handle", &handle_as_value));
+  int handle_as_int = 0;
+  if (!handle_as_value->GetAsInteger(&handle_as_int)) {
+    handle_as_int = 0;
+  }
+
+  const base::Value* flags_as_value = nullptr;
+  CHECK(args->Get("flags", &flags_as_value));
+
+  int flags = MOJO_READ_MESSAGE_FLAG_NONE;
+  if (!flags_as_value->GetAsInteger(&flags)) {
+    flags = MOJO_READ_MESSAGE_FLAG_NONE;
+  }
+
+  uint32_t num_bytes = 0;
+  uint32_t num_handles = 0;
+  mojo::MessagePipeHandle handle(static_cast<MojoHandle>(handle_as_int));
+  MojoResult mojo_result = mojo::ReadMessageRaw(handle, nullptr, &num_bytes,
+                                                nullptr, &num_handles, flags);
+  std::unique_ptr<base::DictionaryValue> result(new base::DictionaryValue);
+
+  if (mojo_result == MOJO_RESULT_RESOURCE_EXHAUSTED) {
+    std::vector<uint8_t> bytes(num_bytes);
+    std::vector<MojoHandle> handles(num_handles);
+    mojo_result = mojo::ReadMessageRaw(handle, bytes.data(), &num_bytes,
+                                       handles.data(), &num_handles, flags);
+
+    base::ListValue* handles_list = new base::ListValue;
+    for (uint32_t i = 0; i < num_handles; i++) {
+      handles_list->AppendInteger(handles[i]);
+    }
+    result->Set("handles", std::unique_ptr<base::Value>(handles_list));
+
+    base::ListValue* buffer = new base::ListValue;
+    for (uint32_t i = 0; i < num_bytes; i++) {
+      buffer->AppendInteger(bytes[i]);
+    }
+    result->Set("buffer", std::unique_ptr<base::Value>(buffer));
+  }
+  result->SetInteger("result", mojo_result);
+
+  return std::unique_ptr<base::Value>(result.release());
+}
+
+std::unique_ptr<base::Value> MojoFacade::HandleSupportWatch(
+    const base::DictionaryValue* args) {
+  int handle = 0;
+  CHECK(args->GetInteger("handle", &handle));
+  int signals = 0;
+  CHECK(args->GetInteger("signals", &signals));
+  int callback_id;
+  CHECK(args->GetInteger("callbackId", &callback_id));
+
+  mojo::Watcher::ReadyCallback callback = base::BindBlock(^(MojoResult result) {
+    NSString* script =
+        [NSString stringWithFormat:@"__crWeb.mojo.signalWatch(%d, %d)",
+                                   callback_id, result];
+    [script_evaluator_ executeJavaScript:script completionHandler:nil];
+  });
+
+  mojo::Watcher& watcher = watchers_[++last_watch_id_];
+  watcher.Start(static_cast<mojo::Handle>(handle), signals, callback);
+  return ValueFromInteger(last_watch_id_);
+}
+
+std::unique_ptr<base::Value> MojoFacade::HandleSupportCancelWatch(
+    const base::DictionaryValue* args) {
+  int watch_id = 0;
+  CHECK(args->GetInteger("watchId", &watch_id));
+  watchers_.erase(watch_id);
+  return nullptr;
+}
+
+}  // namespace web