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| 1 // Copyright (c) 2011 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 CHROME_BROWSER_UI_COCOA_LOOKUP_IN_DICTIONARY_H_ |
| 6 #define CHROME_BROWSER_UI_COCOA_LOOKUP_IN_DICTIONARY_H_ |
| 7 |
| 8 #import <Cocoa/Cocoa.h> |
| 9 |
| 10 #include "base/scoped_nsobject.h" |
| 11 #include "base/synchronization/condition_variable.h" |
| 12 #include "base/synchronization/lock.h" |
| 13 |
| 14 template <typename T> struct DefaultSingletonTraits; |
| 15 |
| 16 // This class helps with the Mac OS X dictionary popup. For the design overview, |
| 17 // look at this document: |
| 18 // http://dev.chromium.org/developers/design-documents/system-dictionary-pop-u
p-architecture |
| 19 // |
| 20 // This service is used to marshall information for these three methods that are |
| 21 // implemented in RenderWidgetHostViewMac: |
| 22 // -[NSTextInput characterIndexForPoint:] |
| 23 // -[NSTextInput attributedSubstringFromRange:] |
| 24 // -[NSTextInput firstRectForCharacterRange:] |
| 25 // |
| 26 // Because these methods are part of a synchronous system API, implementing them |
| 27 // requires getting information from the renderer synchronously. Rather than |
| 28 // using an actual sync IPC message, a normal async ViewMsg is used with a lock |
| 29 // and condition (managed by this service). |
| 30 class LookupInDictionary { |
| 31 public: |
| 32 // Returns the singleton instance. |
| 33 static LookupInDictionary* GetInstance(); |
| 34 |
| 35 // The critical sections that the Condition guards are in RWHVM, specifically |
| 36 // three methods that are part of the NSTextInput protocol that the dictionary |
| 37 // service uses to display the popup. These methods lock the internal |
| 38 // condition for use before the asynchronous message is sent to the renderer |
| 39 // to lookup the required information. These are only used on the UI thread. |
| 40 void BeforeRequest(); |
| 41 // Called at the end of a critical section. This will release the lock and |
| 42 // condition. |
| 43 void AfterRequest(); |
| 44 |
| 45 // Each of the three methods mentioned above has an associated pair of methods |
| 46 // to get data from the renderer. The Wait*() methods block the calling thread |
| 47 // (always the UI thread) with a short timeout after the async message has |
| 48 // been sent to the renderer to lookup the information needed to respond to |
| 49 // the system. The Set*AndSignal() methods store the looked up information in |
| 50 // this service and signal the condition to allow the Wait*() methods to |
| 51 // unlock and return that stored value. |
| 52 // |
| 53 // Returns NSNotFound if the request times out or is not completed. |
| 54 NSUInteger WaitForCharacterIndex(); |
| 55 // Returns nil if the request times out or is completed. |
| 56 NSAttributedString* WaitForSubstring(); |
| 57 // Returns NSZeroRect if the request times out or is not completed. The result |
| 58 // is in WebKit coordinates. |
| 59 NSRect WaitForFirstRect(); |
| 60 |
| 61 // When the renderer sends the ViewHostMsg reply, the RenderMessageFilter will |
| 62 // call the corresponding method on the IO thread to unlock the condition and |
| 63 // allow the Wait*() methods to continue/return. |
| 64 void SetCharacterIndexAndSignal(NSUInteger index); |
| 65 void SetFirstRectAndSignal(NSRect first_rect); |
| 66 void SetSubstringAndSignal(NSAttributedString* string); |
| 67 |
| 68 private: |
| 69 friend struct DefaultSingletonTraits<LookupInDictionary>; |
| 70 LookupInDictionary(); |
| 71 |
| 72 NSUInteger character_index_; |
| 73 NSRect first_rect_; |
| 74 scoped_nsobject<NSAttributedString> substring_; |
| 75 |
| 76 base::Lock lock_; |
| 77 base::ConditionVariable condition_; |
| 78 |
| 79 DISALLOW_COPY_AND_ASSIGN(LookupInDictionary); |
| 80 }; |
| 81 |
| 82 #endif // CHROME_BROWSER_UI_COCOA_LOOKUP_IN_DICTIONARY_H_ |
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