content/browser/renderer_host/text_input_client_mac.h

   1 // Copyright (c) 2012 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 CONTENT_BROWSER_RENDERER_HOST_TEXT_INPUT_CLIENT_MAC_H_
   6 #define CONTENT_BROWSER_RENDERER_HOST_TEXT_INPUT_CLIENT_MAC_H_
   7
   8 #import <Cocoa/Cocoa.h>
   9
  10 #include "base/mac/scoped_nsobject.h"
  11 #include "base/synchronization/condition_variable.h"
  12 #include "base/synchronization/lock.h"
  13 #include "content/common/content_export.h"
  14 #include "ui/gfx/point.h"
  15
  16 template <typename T> struct DefaultSingletonTraits;
  17
  18 namespace content {
  19 class RenderWidgetHost;
  20
  21 // This class helps with the Mac OS X dictionary popup. For the design overview,
  22 // look at this document:
  23 //   http://dev.chromium.org/developers/design-documents/system-dictionary-pop-up-architecture
  24 //
  25 // This service is used to marshall information for these three methods that are
  26 // implemented in RenderWidgetHostViewMac:
  27 //   -[NSTextInput characterIndexForPoint:]
  28 //   -[NSTextInput attributedSubstringFromRange:]
  29 //   -[NSTextInput firstRectForCharacterRange:]
  30 //
  31 // Because these methods are part of a synchronous system API, implementing them
  32 // requires getting information from the renderer synchronously. Rather than
  33 // using an actual sync IPC message, a normal async ViewMsg is used with a lock
  34 // and condition (managed by this service).
  35 class CONTENT_EXPORT TextInputClientMac {
  36  public:
  37   // Returns the singleton instance.
  38   static TextInputClientMac* GetInstance();
  39
  40   // Each of the three methods mentioned above has an associated pair of methods
  41   // to get data from the renderer. The Get*() methods block the calling thread
  42   // (always the UI thread) with a short timeout after the async message has
  43   // been sent to the renderer to lookup the information needed to respond to
  44   // the system. The Set*AndSignal() methods store the looked up information in
  45   // this service and signal the condition to allow the Get*() methods to
  46   // unlock and return that stored value.
  47   //
  48   // Returns NSNotFound if the request times out or is not completed.
  49   NSUInteger GetCharacterIndexAtPoint(RenderWidgetHost* rwh, gfx::Point point);
  50   // Returns nil if the request times out or is completed.
  51   NSAttributedString* GetAttributedSubstringFromRange(
  52       RenderWidgetHost* rwh, NSRange range);
  53   // Returns NSZeroRect if the request times out or is not completed. The result
  54   // is in WebKit coordinates.
  55   NSRect GetFirstRectForRange(RenderWidgetHost* rwh, NSRange range);
  56
  57   // When the renderer sends the ViewHostMsg reply, the RenderMessageFilter will
  58   // call the corresponding method on the IO thread to unlock the condition and
  59   // allow the Get*() methods to continue/return.
  60   void SetCharacterIndexAndSignal(NSUInteger index);
  61   void SetFirstRectAndSignal(NSRect first_rect);
  62   void SetSubstringAndSignal(NSAttributedString* string);
  63
  64  private:
  65   friend struct DefaultSingletonTraits<TextInputClientMac>;
  66   TextInputClientMac();
  67   ~TextInputClientMac();
  68
  69   // The critical sections that the Condition guards are in Get*() methods.
  70   // These methods lock the internal condition for use before the asynchronous
  71   // message is sent to the renderer to lookup the required information. These
  72   // are only used on the UI thread.
  73   void BeforeRequest();
  74   // Called at the end of a critical section. This will release the lock and
  75   // condition.
  76   void AfterRequest();
  77
  78   NSUInteger character_index_;
  79   NSRect first_rect_;
  80   base::scoped_nsobject<NSAttributedString> substring_;
  81
  82   base::Lock lock_;
  83   base::ConditionVariable condition_;
  84
  85   DISALLOW_COPY_AND_ASSIGN(TextInputClientMac);
  86 };
  87
  88 }  // namespace content
  89
  90 #endif  // CONTENT_BROWSER_RENDERER_HOST_TEXT_INPUT_CLIENT_MAC_H_