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_block.h"
  11 #include "base/mac/scoped_nsobject.h"
  12 #include "base/synchronization/condition_variable.h"
  13 #include "base/synchronization/lock.h"
  14 #include "content/common/content_export.h"
  15 #include "ui/gfx/geometry/point.h"
  16
  17 template <typename T> struct DefaultSingletonTraits;
  18
  19 namespace content {
  20 class RenderWidgetHost;
  21
  22 // This class helps with the Mac OS X dictionary popup. For the design overview,
  23 // look at this document:
  24 //   http://dev.chromium.org/developers/design-documents/system-dictionary-pop-up-architecture
  25 //
  26 // This service is used to marshall information for these three methods that are
  27 // implemented in RenderWidgetHostViewMac:
  28 //   -[NSTextInput characterIndexForPoint:]
  29 //   -[NSTextInput attributedSubstringFromRange:]
  30 //   -[NSTextInput firstRectForCharacterRange:]
  31 //
  32 // Because these methods are part of a synchronous system API, implementing them
  33 // requires getting information from the renderer synchronously. Rather than
  34 // using an actual sync IPC message, a normal async ViewMsg is used with a lock
  35 // and condition (managed by this service).
  36 //
  37 // Mac OS 10.8 introduced -[NSResponder quickLookWithEvent:].
  38 // We can use it to implement asynchronous dictionary lookup when the user
  39 // taps a word using three fingers.
  40 // But currently the "Look Up in Dictionary" context menu item still goes
  41 // through the above synchronous IPC.
  42 class CONTENT_EXPORT TextInputClientMac {
  43  public:
  44   // Returns the singleton instance.
  45   static TextInputClientMac* GetInstance();
  46
  47   // Each of the three methods mentioned above has an associated pair of methods
  48   // to get data from the renderer. The Get*() methods block the calling thread
  49   // (always the UI thread) with a short timeout after the async message has
  50   // been sent to the renderer to lookup the information needed to respond to
  51   // the system. The Set*AndSignal() methods store the looked up information in
  52   // this service and signal the condition to allow the Get*() methods to
  53   // unlock and return that stored value.
  54   //
  55   // Returns NSNotFound if the request times out or is not completed.
  56   NSUInteger GetCharacterIndexAtPoint(RenderWidgetHost* rwh, gfx::Point point);
  57   // Returns nil if the request times out or is completed.
  58   NSAttributedString* GetAttributedSubstringFromRange(
  59       RenderWidgetHost* rwh, NSRange range);
  60   // Returns NSZeroRect if the request times out or is not completed. The result
  61   // is in WebKit coordinates.
  62   NSRect GetFirstRectForRange(RenderWidgetHost* rwh, NSRange range);
  63
  64   // When the renderer sends the ViewHostMsg reply, the RenderMessageFilter will
  65   // call the corresponding method on the IO thread to unlock the condition and
  66   // allow the Get*() methods to continue/return.
  67   void SetCharacterIndexAndSignal(NSUInteger index);
  68   void SetFirstRectAndSignal(NSRect first_rect);
  69   void SetSubstringAndSignal(NSAttributedString* string);
  70
  71   // This async method is invoked from RenderWidgetHostViewCocoa's
  72   // -quickLookWithEvent:, when the user taps a word using 3 fingers.
  73   // The reply callback will be invoked from the IO thread, the caller is
  74   // responsible for bouncing to the main thread if necessary.
  75   // The callback parameters provide the attributed word under the point and
  76   // the lower left baseline point of the text.
  77   void GetStringAtPoint(RenderWidgetHost* rwh,
  78                         gfx::Point point,
  79                         void (^replyHandler)(NSAttributedString*, NSPoint));
  80   // This is called on the IO thread when we get the renderer's reply for
  81   // GetStringAtPoint.
  82   void GetStringAtPointReply(NSAttributedString*, NSPoint);
  83
  84  private:
  85   friend struct DefaultSingletonTraits<TextInputClientMac>;
  86   TextInputClientMac();
  87   ~TextInputClientMac();
  88
  89   // The critical sections that the Condition guards are in Get*() methods.
  90   // These methods lock the internal condition for use before the asynchronous
  91   // message is sent to the renderer to lookup the required information. These
  92   // are only used on the UI thread.
  93   void BeforeRequest();
  94   // Called at the end of a critical section. This will release the lock and
  95   // condition.
  96   void AfterRequest();
  97
  98   NSUInteger character_index_;
  99   NSRect first_rect_;
 100   base::scoped_nsobject<NSAttributedString> substring_;
 101
 102   base::Lock lock_;
 103   base::ConditionVariable condition_;
 104
 105   base::mac::ScopedBlock<void(^)(NSAttributedString*, NSPoint)> replyHandler_;
 106
 107   DISALLOW_COPY_AND_ASSIGN(TextInputClientMac);
 108 };
 109
 110 }  // namespace content
 111
 112 #endif  // CONTENT_BROWSER_RENDERER_HOST_TEXT_INPUT_CLIENT_MAC_H_