components/translate/content/renderer/renderer_cld_data_provider.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef COMPONENTS_TRANSLATE_CONTENT_RENDERER_RENDERER_CLD_DATA_PROVIDER_H_
   6 #define COMPONENTS_TRANSLATE_CONTENT_RENDERER_RENDERER_CLD_DATA_PROVIDER_H_
   7
   8 #include "base/callback.h"
   9 #include "base/macros.h"
  10 #include "ipc/ipc_listener.h"
  11
  12 namespace IPC {
  13 class Message;
  14 }
  15
  16 namespace translate {
  17
  18 // Renderer-side interface responsible for providing CLD data.
  19 // The embedder should set an instance as soon as feasible during startup.
  20 // The implementation must be paired with a browser-side implementation of
  21 // the BrowserCldDataProvider class, typically created by a
  22 // BrowserCldDataProviderFactory:
  23 //   ../browser/browser_cld_data_provider_factory.h
  24 //   ../browser/browser_cld_data_provider.h
  25 //
  26 // The glue between the browser and renderer processes is typically a pair of
  27 // request/response IPC messages using the CldDataProviderMsgStart
  28 // "IPCMessageStart" enumerated constant from ipc_message_start.h.
  29 class RendererCldDataProvider : public IPC::Listener {
  30  public:
  31   RendererCldDataProvider();
  32   ~RendererCldDataProvider() override {}
  33
  34   // (Inherited from IPC::Listener)
  35   // If the specified message is a response for CLD data, attempts to
  36   // initialize CLD2 and returns true in all cases. If initialization is
  37   // successful and a callback has been configured via
  38   // SetCldAvailableCallback(...), that callback is invoked from the message
  39   // loop thread.
  40   // This method is defined as virtual in order to force the implementation to
  41   // define the specific IPC message(s) that it handles.
  42   // The default implementation does nothing and returns false.
  43   bool OnMessageReceived(const IPC::Message& message) override;
  44
  45   // Invoked by the renderer process to request that CLD data be obtained and
  46   // that CLD be initialized with it. The implementation is expected to
  47   // communicate with the paired BrowserCldDataProvider implementation on the
  48   // browser side.
  49   // This method must be invoked on the message loop thread.
  50   // The default implementation does nothing.
  51   virtual void SendCldDataRequest() {}
  52
  53   // Convenience method that tracks whether or not CLD data is available.
  54   // This method can be used in the absence of a callback (i.e., if the caller
  55   // wants a simple way to check the state of CLD data availability without
  56   // keeping a separate boolean flag tripped by a callback).
  57   // The default implementation always returns true.
  58   virtual bool IsCldDataAvailable();
  59
  60   // Sets a callback that will be invoked when CLD data is successfully
  61   // obtained from the paired BrowserCldDataProvider implementation on the
  62   // browser side, after CLD has been successfully initialized.
  63   // Both the initialization of CLD2 as well as the invocation of the callback
  64   // must happen on the message loop thread.
  65   // The default implementation immediately invokes the callback.
  66   virtual void SetCldAvailableCallback(base::Callback<void(void)> callback);
  67
  68  private:
  69   DISALLOW_COPY_AND_ASSIGN(RendererCldDataProvider);
  70 };
  71
  72 }  // namespace translate
  73
  74 #endif  // COMPONENTS_TRANSLATE_CONTENT_RENDERER_RENDERER_CLD_DATAP_PROVIDER_H_