content/browser/web_contents/web_drag_dest_gtk.h

   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_WEB_CONTENTS_WEB_DRAG_DEST_GTK_H_
   6 #define CONTENT_BROWSER_WEB_CONTENTS_WEB_DRAG_DEST_GTK_H_
   7
   8 #include <gtk/gtk.h>
   9
  10 #include "base/gtest_prod_util.h"
  11 #include "base/memory/scoped_ptr.h"
  12 #include "base/memory/weak_ptr.h"
  13 #include "content/common/content_export.h"
  14 #include "content/public/common/drop_data.h"
  15 #include "third_party/WebKit/public/web/WebDragOperation.h"
  16 #include "ui/base/gtk/gtk_signal.h"
  17
  18 namespace content {
  19
  20 class RenderViewHostImpl;
  21 class WebContents;
  22 class WebDragDestDelegate;
  23
  24 // A helper class that handles DnD for drops in the renderer. In GTK parlance,
  25 // this handles destination-side DnD, but not source-side DnD.
  26 class CONTENT_EXPORT WebDragDestGtk {
  27  public:
  28   WebDragDestGtk(WebContents* web_contents, GtkWidget* widget);
  29   ~WebDragDestGtk();
  30
  31   DropData* current_drop_data() const { return drop_data_.get(); }
  32
  33   // This is called when the renderer responds to a drag motion event. We must
  34   // update the system drag cursor.
  35   void UpdateDragStatus(blink::WebDragOperation operation);
  36
  37   // Informs the renderer when a system drag has left the render view.
  38   // See OnDragLeave().
  39   void DragLeave();
  40
  41   WebDragDestDelegate* delegate() const { return delegate_; }
  42   void set_delegate(WebDragDestDelegate* delegate) { delegate_ = delegate; }
  43
  44   GtkWidget* widget() const { return widget_; }
  45
  46  private:
  47   RenderViewHostImpl* GetRenderViewHost() const;
  48
  49   // Called when a system drag crosses over the render view. As there is no drag
  50   // enter event, we treat it as an enter event (and not a regular motion event)
  51   // when |context_| is NULL.
  52   CHROMEGTK_CALLBACK_4(WebDragDestGtk, gboolean, OnDragMotion, GdkDragContext*,
  53                        gint, gint, guint);
  54
  55   // We make a series of requests for the drag data when the drag first enters
  56   // the render view. This is the callback that is used to give us the data
  57   // for each individual target. When |data_requests_| reaches 0, we know we
  58   // have attained all the data, and we can finally tell the renderer about the
  59   // drag.
  60   CHROMEGTK_CALLBACK_6(WebDragDestGtk, void, OnDragDataReceived,
  61                        GdkDragContext*, gint, gint, GtkSelectionData*,
  62                        guint, guint);
  63
  64   // The drag has left our widget; forward this information to the renderer.
  65   CHROMEGTK_CALLBACK_2(WebDragDestGtk, void, OnDragLeave, GdkDragContext*,
  66                        guint);
  67
  68   // Called by GTK when the user releases the mouse, executing a drop.
  69   CHROMEGTK_CALLBACK_4(WebDragDestGtk, gboolean, OnDragDrop, GdkDragContext*,
  70                        gint, gint, guint);
  71
  72   WebContents* web_contents_;
  73
  74   // The render view.
  75   GtkWidget* widget_;
  76
  77   // The current drag context for system drags over our render view, or NULL if
  78   // there is no system drag or the system drag is not over our render view.
  79   GdkDragContext* context_;
  80
  81   // The data for the current drag, or NULL if |context_| is NULL.
  82   scoped_ptr<DropData> drop_data_;
  83
  84   // The number of outstanding drag data requests we have sent to the drag
  85   // source.
  86   int data_requests_;
  87
  88   // The last time we sent a message to the renderer related to a drag motion.
  89   gint drag_over_time_;
  90
  91   // Whether the cursor is over a drop target, according to the last message we
  92   // got from the renderer.
  93   bool is_drop_target_;
  94
  95   // Stores Handler IDs for the gtk signal handlers. We have to cancel the
  96   // signal handlers when this WebDragDestGtk is deleted so that if, later on,
  97   // we re-create the drag dest with the same widget, we don't get callbacks to
  98   // deleted functions.
  99   scoped_ptr<int[]> handlers_;
 100
 101   // A delegate that can receive drag information about drag events.
 102   WebDragDestDelegate* delegate_;
 103
 104   // True if the drag has been canceled.
 105   bool canceled_;
 106
 107   base::WeakPtrFactory<WebDragDestGtk> method_factory_;
 108
 109   DISALLOW_COPY_AND_ASSIGN(WebDragDestGtk);
 110 };
 111
 112 }  // namespace content
 113
 114 #endif  // CONTENT_BROWSER_WEB_CONTENTS_WEB_DRAG_DEST_GTK_H_