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