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1 // Copyright (c) 2009 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2009 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef GFX_GTK_NATIVE_VIEW_ID_MANAGER_H_ | 5 #ifndef GFX_GTK_NATIVE_VIEW_ID_MANAGER_H_ |
6 #define GFX_GTK_NATIVE_VIEW_ID_MANAGER_H_ | 6 #define GFX_GTK_NATIVE_VIEW_ID_MANAGER_H_ |
7 #pragma once | 7 #pragma once |
8 | 8 |
9 #include <map> | 9 #include "ui/gfx/gtk_native_view_id_manager.h" |
10 | 10 // TODO(sail): remove this file once all includes have been updated. |
11 #include "base/singleton.h" | |
12 #include "base/synchronization/lock.h" | |
13 #include "gfx/native_widget_types.h" | |
14 | |
15 typedef unsigned long XID; | |
16 struct _GtkPreserveWindow; | |
17 | |
18 // NativeViewIds are the opaque values which the renderer holds as a reference | |
19 // to a window. These ids are often used in sync calls from the renderer and | |
20 // one cannot terminate sync calls on the UI thread as that can lead to | |
21 // deadlocks. | |
22 // | |
23 // Because of this, we have the BACKGROUND_X11 thread for these calls and this | |
24 // thread has a separate X connection in order to answer them. But one cannot | |
25 // use GTK on multiple threads, so the BACKGROUND_X11 thread deals only in Xlib | |
26 // calls and, thus, XIDs. | |
27 // | |
28 // So we could make NativeViewIds be the X id of the window. However, at the | |
29 // time when we need to tell the renderer about its NativeViewId, an XID isn't | |
30 // availible and it goes very much against the grain of the code to make it so. | |
31 // Also, we worry that GTK might choose to change the underlying X window id | |
32 // when, say, the widget is hidden or repacked. Finally, if we used XIDs then a | |
33 // compromised renderer could start asking questions about any X windows on the | |
34 // system. | |
35 // | |
36 // Thus, we have this object. It produces random NativeViewIds from GtkWidget | |
37 // pointers and observes the various signals from the widget for when an X | |
38 // window is created, destroyed etc. Thus it provides a thread safe mapping | |
39 // from NativeViewIds to the current XID for that widget. | |
40 class GtkNativeViewManager { | |
41 public: | |
42 // Returns the singleton instance. | |
43 static GtkNativeViewManager* GetInstance(); | |
44 | |
45 // Must be called from the UI thread: | |
46 // | |
47 // Return a NativeViewId for the given widget and attach to the various | |
48 // signals emitted by that widget. The NativeViewId is pseudo-randomly | |
49 // allocated so that a compromised renderer trying to guess values will fail | |
50 // with high probability. The NativeViewId will not be reused for the | |
51 // lifetime of the GtkWidget. | |
52 gfx::NativeViewId GetIdForWidget(gfx::NativeView widget); | |
53 | |
54 // May be called from any thread: | |
55 // | |
56 // xid: (output) the resulting X window ID, or 0 | |
57 // id: a value previously returned from GetIdForWidget | |
58 // returns: true if |id| is a valid id, false otherwise. | |
59 // | |
60 // If the widget referenced by |id| does not current have an X window id, | |
61 // |*xid| is set to 0. | |
62 bool GetXIDForId(XID* xid, gfx::NativeViewId id); | |
63 | |
64 // Must be called from the UI thread because we may need the associated | |
65 // widget to create a window. | |
66 // | |
67 // Keeping the XID permanent requires a bit of overhead, so it must | |
68 // be explicitly requested. | |
69 // | |
70 // xid: (output) the resulting X window | |
71 // id: a value previously returned from GetIdForWidget | |
72 // returns: true if |id| is a valid id, false otherwise. | |
73 bool GetPermanentXIDForId(XID* xid, gfx::NativeViewId id); | |
74 | |
75 // Must be called from the UI thread because we may need to access a | |
76 // GtkWidget or destroy a GdkWindow. | |
77 // | |
78 // If the widget associated with the XID is still alive, allow the widget | |
79 // to destroy the associated XID when it wants. Otherwise, destroy the | |
80 // GdkWindow associated with the XID. | |
81 void ReleasePermanentXID(XID xid); | |
82 | |
83 // These are actually private functions, but need to be called from statics. | |
84 void OnRealize(gfx::NativeView widget); | |
85 void OnUnrealize(gfx::NativeView widget); | |
86 void OnDestroy(gfx::NativeView widget); | |
87 | |
88 base::Lock& unrealize_lock() { return unrealize_lock_; } | |
89 | |
90 private: | |
91 // This object is a singleton: | |
92 GtkNativeViewManager(); | |
93 ~GtkNativeViewManager(); | |
94 friend struct DefaultSingletonTraits<GtkNativeViewManager>; | |
95 | |
96 struct NativeViewInfo { | |
97 NativeViewInfo() : widget(NULL), x_window_id(0) { | |
98 } | |
99 gfx::NativeView widget; | |
100 XID x_window_id; | |
101 }; | |
102 | |
103 gfx::NativeViewId GetWidgetId(gfx::NativeView id); | |
104 | |
105 // This lock can be used to block GTK from unrealizing windows. This is needed | |
106 // when the BACKGROUND_X11 thread is using a window obtained via GetXIDForId, | |
107 // and can't allow the X11 resource to be deleted. | |
108 base::Lock unrealize_lock_; | |
109 | |
110 // protects native_view_to_id_ and id_to_info_ | |
111 base::Lock lock_; | |
112 | |
113 // If asked for an id for the same widget twice, we want to return the same | |
114 // id. So this records the current mapping. | |
115 std::map<gfx::NativeView, gfx::NativeViewId> native_view_to_id_; | |
116 std::map<gfx::NativeViewId, NativeViewInfo> id_to_info_; | |
117 | |
118 struct PermanentXIDInfo { | |
119 PermanentXIDInfo() : widget(NULL), ref_count(0) { | |
120 } | |
121 _GtkPreserveWindow* widget; | |
122 int ref_count; | |
123 }; | |
124 | |
125 // Used to maintain the reference count for permanent XIDs | |
126 // (referenced by GetPermanentXIDForId and dereferenced by | |
127 // ReleasePermanentXID). Only those XIDs with a positive reference count | |
128 // will be in the table. | |
129 // | |
130 // In general, several GTK widgets may share the same X window. We assume | |
131 // that is not true of the widgets stored in this registry. | |
132 // | |
133 // An XID will map to NULL, if there is an outstanding reference but the | |
134 // widget was destroyed. In this case, the destruction of the X window | |
135 // is deferred to the dropping of all references. | |
136 std::map<XID, PermanentXIDInfo> perm_xid_to_info_; | |
137 | |
138 DISALLOW_COPY_AND_ASSIGN(GtkNativeViewManager); | |
139 }; | |
140 | 11 |
141 #endif // GFX_GTK_NATIVE_VIEW_ID_MANAGER_H_ | 12 #endif // GFX_GTK_NATIVE_VIEW_ID_MANAGER_H_ |
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