Componentize html_viewer's MessagePort

We should transition to using the same implementation in content, and this
is the first step to doing that.

BUG=361001
R=jam@chromium.org
TBR=jochen@chromium.org (+WebKit DEPS)

Review URL: https://codereview.chromium.org/1182303012

Cr-Commit-Position: refs/heads/master@{#334914}

5 files changed, 202 insertions, 0 deletions

diff --git a/components/message_port/BUILD.gn b/components/message_port/BUILD.gn
new file mode 100644
index 0000000..3a81750
--- /dev/null
+++ b/components/message_port/BUILD.gn
@@ -0,0 +1,17 @@
+# Copyright 2015 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.
+
+source_set("message_port") {
+  sources = [
+    "web_message_port_channel_impl.cc",
+    "web_message_port_channel_impl.h",
+  ]
+
+  public_deps = [
+    "//base",
+    "//mojo/common",
+    "//third_party/WebKit/public:blink",
+    "//third_party/mojo/src/mojo/public/cpp/system",
+  ]
+}
diff --git a/components/message_port/DEPS b/components/message_port/DEPS
new file mode 100644
index 0000000..eba876f
--- /dev/null
+++ b/components/message_port/DEPS
@@ -0,0 +1,6 @@
+include_rules = [
+  "+base",
+  "+mojo/common",
+  "+third_party/WebKit/public",
+  "+third_party/mojo/src/mojo/public/cpp/system",
+]
diff --git a/components/message_port/OWNERS b/components/message_port/OWNERS
new file mode 100644
index 0000000..80b8751
--- /dev/null
+++ b/components/message_port/OWNERS
@@ -0,0 +1,2 @@
+jam@chromium.org
+rockot@chromium.org
diff --git a/components/message_port/web_message_port_channel_impl.cc b/components/message_port/web_message_port_channel_impl.cc
new file mode 100644
index 0000000..93a6212
--- /dev/null
+++ b/components/message_port/web_message_port_channel_impl.cc
@@ -0,0 +1,132 @@
+// Copyright 2015 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.
+
+#include "components/message_port/web_message_port_channel_impl.h"
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "base/strings/string16.h"
+#include "third_party/WebKit/public/platform/WebMessagePortChannelClient.h"
+#include "third_party/WebKit/public/platform/WebString.h"
+#include "third_party/mojo/src/mojo/public/cpp/system/message_pipe.h"
+
+using blink::WebMessagePortChannel;
+using blink::WebMessagePortChannelArray;
+using blink::WebMessagePortChannelClient;
+using blink::WebString;
+
+namespace message_port {
+
+void WebMessagePortChannelImpl::CreatePair(
+    blink::WebMessagePortChannel** channel1,
+    blink::WebMessagePortChannel** channel2) {
+  mojo::ScopedMessagePipeHandle pipe1;
+  mojo::ScopedMessagePipeHandle pipe2;
+  MojoResult result = mojo::CreateMessagePipe(nullptr, &pipe1, &pipe2);
+  if (result != MOJO_RESULT_OK) {
+    NOTREACHED();
+    return;
+  }
+
+  *channel1 = new WebMessagePortChannelImpl(pipe1.Pass());;
+  *channel2 = new WebMessagePortChannelImpl(pipe2.Pass());
+}
+
+WebMessagePortChannelImpl::WebMessagePortChannelImpl(
+    mojo::ScopedMessagePipeHandle pipe)
+    : client_(nullptr), pipe_(pipe.Pass()) {
+  WaitForNextMessage();
+}
+
+WebMessagePortChannelImpl::~WebMessagePortChannelImpl() {
+}
+
+void WebMessagePortChannelImpl::setClient(WebMessagePortChannelClient* client) {
+  client_ = client;
+}
+
+void WebMessagePortChannelImpl::destroy() {
+  setClient(nullptr);
+  delete this;
+}
+
+void WebMessagePortChannelImpl::postMessage(
+    const WebString& message_as_string,
+    WebMessagePortChannelArray* channels) {
+  base::string16 string = message_as_string;
+
+  std::vector<MojoHandle> handles;
+  if (channels) {
+    for (size_t i = 0; i < channels->size(); ++i) {
+      WebMessagePortChannelImpl* channel =
+          static_cast<WebMessagePortChannelImpl*>((*channels)[i]);
+      handles.push_back(channel->pipe_.release().value());
+      channel->handle_watcher_.Stop();
+    }
+    delete channels;
+  }
+
+  uint32_t num_handles = static_cast<uint32_t>(handles.size());
+  MojoHandle* handles_ptr = handles.empty() ? nullptr : &handles[0];
+
+  MojoResult result = MojoWriteMessage(
+      pipe_.get().value(), string.c_str(),
+      static_cast<uint32_t>(string.length() * sizeof(base::char16)),
+      handles_ptr, num_handles, MOJO_WRITE_MESSAGE_FLAG_NONE);
+  DCHECK_EQ(MOJO_RESULT_OK, result);
+}
+
+bool WebMessagePortChannelImpl::tryGetMessage(
+    WebString* message,
+    WebMessagePortChannelArray& channels) {
+  uint32_t num_bytes = 0;
+  uint32_t num_handles = 0;
+  MojoResult result = MojoReadMessage(
+      pipe_.get().value(), nullptr, &num_bytes, nullptr, &num_handles,
+      MOJO_READ_MESSAGE_FLAG_NONE);
+  if (result != MOJO_RESULT_RESOURCE_EXHAUSTED)
+    return false;
+
+  base::string16 message16;
+  CHECK(num_bytes % sizeof(base::char16) == 0);
+  message16.resize(num_bytes / sizeof(base::char16));
+  std::vector<MojoHandle> handles;
+  handles.resize(num_handles);
+
+  MojoHandle* handles_ptr = handles.empty() ? nullptr : &handles[0];
+  result = MojoReadMessage(
+      pipe_.get().value(), &message16[0], &num_bytes, handles_ptr, &num_handles,
+      MOJO_READ_MESSAGE_FLAG_NONE);
+  if (result != MOJO_RESULT_OK) {
+    NOTREACHED();
+    return false;
+  }
+
+  *message = message16;
+  WebMessagePortChannelArray ports(handles.size());
+  for (size_t i = 0; i < handles.size(); ++i) {
+    mojo::MessagePipeHandle mph(handles[i]);
+    mojo::ScopedMessagePipeHandle handle(mph);
+    ports[i] = new WebMessagePortChannelImpl(handle.Pass());
+  }
+  channels = ports;
+  return true;
+}
+
+void WebMessagePortChannelImpl::WaitForNextMessage() {
+  handle_watcher_.Start(
+      pipe_.get(),
+      MOJO_HANDLE_SIGNAL_READABLE,
+      MOJO_DEADLINE_INDEFINITE,
+      base::Bind(&WebMessagePortChannelImpl::OnMessageAvailable,
+                 base::Unretained(this)));
+}
+
+void WebMessagePortChannelImpl::OnMessageAvailable(MojoResult result) {
+  DCHECK_EQ(MOJO_RESULT_OK, result);
+  client_->messageAvailable();
+  WaitForNextMessage();
+}
+
+}  // namespace message_port
diff --git a/components/message_port/web_message_port_channel_impl.h b/components/message_port/web_message_port_channel_impl.h
new file mode 100644
index 0000000..49fe97e
--- /dev/null
+++ b/components/message_port/web_message_port_channel_impl.h
@@ -0,0 +1,45 @@
+// Copyright 2015 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.
+
+#ifndef COMPONENTS_MESSAGE_PORT_WEB_MESSAGE_PORT_CHANNEL_IMPL_H_
+#define COMPONENTS_MESSAGE_PORT_WEB_MESSAGE_PORT_CHANNEL_IMPL_H_
+
+#include "base/basictypes.h"
+#include "mojo/common/handle_watcher.h"
+#include "third_party/WebKit/public/platform/WebMessagePortChannel.h"
+#include "third_party/mojo/src/mojo/public/cpp/system/message_pipe.h"
+
+namespace message_port {
+
+class WebMessagePortChannelImpl : public blink::WebMessagePortChannel {
+ public:
+  static void CreatePair(
+      blink::WebMessagePortChannel** channel1,
+      blink::WebMessagePortChannel** channel2);
+
+ private:
+  explicit WebMessagePortChannelImpl(mojo::ScopedMessagePipeHandle pipe);
+  virtual ~WebMessagePortChannelImpl();
+
+  // blink::WebMessagePortChannel implementation.
+  virtual void setClient(blink::WebMessagePortChannelClient* client);
+  virtual void destroy();
+  virtual void postMessage(const blink::WebString& message,
+                           blink::WebMessagePortChannelArray* channels);
+  virtual bool tryGetMessage(blink::WebString* message,
+                             blink::WebMessagePortChannelArray& channels);
+
+  void WaitForNextMessage();
+  void OnMessageAvailable(MojoResult result);
+
+  blink::WebMessagePortChannelClient* client_;
+  mojo::ScopedMessagePipeHandle pipe_;
+  mojo::common::HandleWatcher handle_watcher_;
+
+  DISALLOW_COPY_AND_ASSIGN(WebMessagePortChannelImpl);
+};
+
+}  // namespace message_port
+
+#endif  // COMPONENTS_MESSAGE_PORT_WEB_MESSAGE_PORT_CHANNEL_IMPL_H_