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/point.h"
16
17template <typename T> struct DefaultSingletonTraits;
18
19namespace content {
20class 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.
42class 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_
113