aura-x11: Add custom web cursor support.

ui/base/x/x11_util.cc

Index: ui/base/x/x11_util.cc
diff --git a/ui/base/x/x11_util.cc b/ui/base/x/x11_util.cc
index 288344828ee8620707daa7b597a22f93af4627ab..676bb8f04ac014fedff9f9b6cc820990ed2665b6 100644
--- a/ui/base/x/x11_util.cc
+++ b/ui/base/x/x11_util.cc
@@ -35,6 +35,10 @@
 #include <sys/sysctl.h>
 #endif
 
+#if defined(USE_AURA)
+#include <X11/Xcursor/Xcursor.h>
+#endif
+
 #if defined(TOOLKIT_USES_GTK)
 #include <gdk/gdk.h>
 #include <gdk/gdkx.h>
@@ -188,6 +192,80 @@ class XCursorCache {
   DISALLOW_COPY_AND_ASSIGN(XCursorCache);
 };
 
+#if defined(USE_AURA)
+// A process wide singleton cache for custom X cursors.
+class XCustomCursorCache {
+ public:
+  static XCustomCursorCache* GetInstance() {
+    return Singleton<XCustomCursorCache>::get();
+  }
+
+  Cursor InstallCustomCursor(XcursorImage* image) {
+    Cursor xcursor = XcursorImageLoadCursor(GetXDisplay(), image);
+    XCustomCursor* custom_cursor = new XCustomCursor(image);
+    cache_[xcursor] = custom_cursor;
+    return xcursor;
+  }
+
+  void Ref(Cursor cursor) {
+    cache_[cursor]->Ref();
+  }
+
+  void Unref(Cursor cursor) {
+    if (cache_[cursor]->Unref()) {
+      XFreeCursor(GetXDisplay(), cursor);
+      cache_.erase(cursor);
+    }
+  }
+
+  void Clear() {
+    cache_.clear();

[Daniel Erat, 2012/02/24 21:04:36]

do you need to call XFreeCursor() on all of the keys here?

[sadrul, 2012/02/24 22:48:49]

Good catch. This needs to happen. I have moved the Cursor ownership from
XCustomCursorCache to XCustomCursor, and the cursor is free'd from its
destructor.

+  }
+
+ private:
+  friend struct DefaultSingletonTraits<XCustomCursorCache>;
+
+  class XCustomCursor {
+   public:
+    XCustomCursor(XcursorImage* image)

[Daniel Erat, 2012/02/24 21:04:36]

nit: document that it takes ownership of |image|

[sadrul, 2012/02/24 22:48:49]

Done.

+        : image_(image),
+          ref_(1) {
+    }
+
+    ~XCustomCursor() {
+      XcursorImageDestroy(image_);
+    }
+
+    void Ref() {
+      ++ref_;
+    }
+
+    // Returns true if the cursor was destroyed because of the unref.
+    bool Unref() {
+      if (--ref_ == 0) {
+        delete this;
+        return true;
+      }
+      return false;
+    }
+
+   private:
+    XcursorImage* image_;
+    int ref_;
+
+    DISALLOW_COPY_AND_ASSIGN(XCustomCursor);
+  };
+
+  XCustomCursorCache() {}
+  ~XCustomCursorCache() {
+    Clear();
+  }
+
+  std::map<Cursor, XCustomCursor*> cache_;
+  DISALLOW_COPY_AND_ASSIGN(XCustomCursorCache);
+};
+#endif  // defined(USE_AURA)
+
 // A singleton object that remembers remappings of mouse buttons.
 class XButtonMap {
  public:
@@ -317,6 +395,20 @@ Cursor GetXCursor(int cursor_shape) {
   return cache.GetCursor(cursor_shape);
 }
 
+#if defined(USE_AURA)
+Cursor CreateReffedCustomXCursor(XcursorImage* image) {
+  return XCustomCursorCache::GetInstance()->InstallCustomCursor(image);
+}
+
+void RefCustomXCursor(Cursor cursor) {
+  XCustomCursorCache::GetInstance()->Ref(cursor);
+}
+
+void UnrefCustomXCursor(Cursor cursor) {
+  XCustomCursorCache::GetInstance()->Unref(cursor);
+}
+#endif
+
 XID GetX11RootWindow() {
   return DefaultRootWindow(GetXDisplay());
 }