Native Messaging!

chrome/browser/extensions/api/messaging/native_message_process_host.h

+// Copyright (c) 2012 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 CHROME_BROWSER_EXTENSIONS_API_MESSAGING_NATIVE_MESSAGE_PROCESS_HOST_H_
+#define CHROME_BROWSER_EXTENSIONS_API_MESSAGING_NATIVE_MESSAGE_PROCESS_HOST_H_
+
+#include "base/file_util.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/message_loop.h"
+#include "base/process.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace extensions {
+class NativeProcessLauncher;
+
+// Manages the native side of a connection between an extension and a native
+// process.
+//
+// This class must only be created, called, and deleted on the FILE thread.
+// Public methods typically accept callbacks which will be invoked on the UI
+// thread.
+class NativeMessageProcessHost
+#if defined(OS_WIN)
+    : public MessageLoopForIO::IOHandler {
+#else
+    : public MessageLoopForIO::Watcher {
+#endif  // defined(OS_WIN)
+ public:
+  class ScopedNativeProcessClose;
+
+#if defined(OS_WIN)
+  typedef HANDLE FileHandle;
+  typedef win::base::ScopedHandle ScopedFileHandle;
+#else
+  typedef int FileHandle;
+  typedef file_util::ScopedFD ScopedFileHandle;
+#endif  // defined(OS_WIN)
+
+  typedef scoped_ptr_malloc<NativeMessageProcessHost, ScopedNativeProcessClose>
+      ScopedNativeMessageProcessHost;

[Matt Perry, 2012/09/06 00:40:01]

nit: since this typedef is contained in the class, you could shorten its name to
something like "ScopedInstance" or "ScopedHost"

[eaugusti, 2012/09/13 17:24:28]

Done.

+
+  typedef base::Callback<void(ScopedNativeMessageProcessHost host)>
+      CreateCallback;
+
+  // Append any new types to the end. Changing the ordering will break native
+  // apps.
+  enum MessageType {
+    TYPE_SEND_MESSAGE_REQUEST,  // Used when an extension is sending a one-off
+                                // message to a native app.
+    TYPE_SEND_MESSAGE_RESPONSE,  // Used by a native app to respond to a one-off
+                                 // message.
+    TYPE_CONNECT,  // Used when an extension wants to establish a persistent
+                   // connection with a native app.
+    TYPE_CONNECT_MESSAGE,  // Used for messages after a connection has already
+                           // been established.
+    NUM_MESSAGE_TYPES  // The number of types of messages.
+  };
+
+  // Interface for classes that which to recieve messages from the native
+  // process.
+  class Client {
+   public:
+    virtual ~Client() {}
+    // Called on the UI thread.
+    virtual void PostMessageFromNativeProcess(int port_id,
+                                              const std::string& message) = 0;
+    virtual void CloseChannel(int port_id, bool error) = 0;
+  };
+
+  // Desctruction functor that ensures a NativeMessageProcessHost is destroyed
+  // on the FILE thread.
+  class ScopedNativeProcessClose {
+   public:
+    inline void operator()(extensions::NativeMessageProcessHost* x) const {
+      content::BrowserThread::DeleteSoon(content::BrowserThread::FILE,
+                                        FROM_HERE, x);
+    }
+  };
+
+
+  ~NativeMessageProcessHost();
+
+  // |type| must be TYPE_CONNECT or TYPE_SEND_MESSAGE_REQUEST.
+  // |callback| will be called with a NULL on error.
+  static void Create(base::WeakPtr<Client> weak_client_ui,
+                     const std::string& native_app_name,
+                     const std::string& connection_message,
+                     int destination_port,
+                     MessageType type,
+                     CreateCallback callback);
+
+  // Create a NativeMessageProcessHost using the specified launcher. This allows
+  // for easy testing.
+  static void CreateWithLauncher(base::WeakPtr<Client> weak_client_ui,
+                                 const std::string& native_app_name,
+                                 const std::string& connection_message,
+                                 int destination_port,
+                                 MessageType type,
+                                 CreateCallback callback,
+                                 const NativeProcessLauncher& launcher);
+
+  // TYPE_SEND_MESSAGE_REQUEST will be sent via the connection message in
+  // NativeMessageProcessHost::Create, so only TYPE_CONNECT_MESSAGE is expected.
+  void Send(const std::string& json) {
+    SendImpl(TYPE_CONNECT_MESSAGE, json);
+  }
+
+  // Try and read a single message from |read_file_|. This should only be called
+  // in unittests when you know there is data in the file.
+  void ReadNowForTesting();
+
+ private:
+  NativeMessageProcessHost(base::WeakPtr<Client> weak_client_ui,
+                           int destination_port,
+                           base::ProcessHandle native_process_handle,
+                           FileHandle read_fd,
+                           FileHandle write_fd,
+                           bool is_send_message);
+
+  // Initialize any IO watching that needs to occur between the native process.
+  void InitIO();
+
+  // Send a message to the native process with the specified type and payload.
+  void SendImpl(MessageType type, const std::string& json);
+
+  // Write a message/data to the native process.
+  bool WriteMessage(MessageType type, const std::string& message);
+  bool WriteData(FileHandle file, const char* data, size_t bytes_to_write);
+
+  // Read a message/data from the native process.
+  bool ReadMessage(MessageType* type, std::string* messgae);
+  bool ReadData(FileHandle file, char* data, size_t bytes_to_write);
+
+#if defined(OS_POSIX)
+  // MessageLoopForIO::Watcher
+  virtual void OnFileCanReadWithoutBlocking(int fd);
+  // We don't need to watch for writes.
+  virtual void OnFileCanWriteWithoutBlocking(int fd) {}
+
+  MessageLoopForIO::FileDescriptorWatcher read_watcher_;
+#endif  // defined(OS_POSIX)
+
+#if defined(OS_WIN)
+  // MessageLoopForIO::IOHandler
+  virtual void OnIOCompleted(IOContext* context,
+                             DWORD bytes_transfered,
+                             DWORD error);
+
+  MessageLoopForIO::IOContext read_context_;
+  MessageLoopForIO::IOContext write_context_;
+#endif  // defined(OS_WIN)
+
+
+  // The Client messages will be posted to. Should only be accessed from the
+  // UI thread.
+  base::WeakPtr<Client> weak_client_ui_;
+
+  // The id of the port on the other side of this connection. This is passed to
+  // |weak_client_ui_| when posting messages.
+  int destination_port_;
+
+  base::ProcessHandle native_process_handle_;
+
+  FileHandle read_file_;
+  FileHandle write_file_;
+  ScopedFileHandle scoped_read_file_;
+  ScopedFileHandle scoped_write_file_;
+
+  // Only looking for one response.
+  bool is_send_message_;
+
+  DISALLOW_COPY_AND_ASSIGN(NativeMessageProcessHost);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_MESSAGING_NATIVE_MESSAGE_PROCESS_HOST_H__