1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/ipc/chromium/src/base/base_drop_target.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,130 @@
1.4 +// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
1.5 +// Use of this source code is governed by a BSD-style license that can be
1.6 +// found in the LICENSE file.
1.7 +
1.8 +#ifndef BASE_BASE_DROP_TARGET_H_
1.9 +#define BASE_BASE_DROP_TARGET_H_
1.10 +
1.11 +#include <objidl.h>
1.12 +
1.13 +#include "base/ref_counted.h"
1.14 +
1.15 +struct IDropTargetHelper;
1.16 +
1.17 +// A DropTarget implementation that takes care of the nitty gritty
1.18 +// of dnd. While this class is concrete, subclasses will most likely
1.19 +// want to override various OnXXX methods.
1.20 +//
1.21 +// Because BaseDropTarget is ref counted you shouldn't delete it directly,
1.22 +// rather wrap it in a scoped_refptr. Be sure and invoke RevokeDragDrop(m_hWnd)
1.23 +// before the HWND is deleted too.
1.24 +//
1.25 +// This class is meant to be used in a STA and is not multithread-safe.
1.26 +class BaseDropTarget : public IDropTarget {
1.27 + public:
1.28 + // Create a new BaseDropTarget associating it with the given HWND.
1.29 + explicit BaseDropTarget(HWND hwnd);
1.30 + virtual ~BaseDropTarget();
1.31 +
1.32 + // When suspend is set to |true|, the drop target does not receive drops from
1.33 + // drags initiated within the owning HWND.
1.34 + // TODO(beng): (http://b/1085385) figure out how we will handle legitimate
1.35 + // drag-drop operations within the same HWND, such as dragging
1.36 + // selected text to an edit field.
1.37 + void set_suspend(bool suspend) { suspend_ = suspend; }
1.38 +
1.39 + // IDropTarget implementation:
1.40 + HRESULT __stdcall DragEnter(IDataObject* data_object,
1.41 + DWORD key_state,
1.42 + POINTL cursor_position,
1.43 + DWORD* effect);
1.44 + HRESULT __stdcall DragOver(DWORD key_state,
1.45 + POINTL cursor_position,
1.46 + DWORD* effect);
1.47 + HRESULT __stdcall DragLeave();
1.48 + HRESULT __stdcall Drop(IDataObject* data_object,
1.49 + DWORD key_state,
1.50 + POINTL cursor_position,
1.51 + DWORD* effect);
1.52 +
1.53 + // IUnknown implementation:
1.54 + HRESULT __stdcall QueryInterface(const IID& iid, void** object);
1.55 + ULONG __stdcall AddRef();
1.56 + ULONG __stdcall Release();
1.57 +
1.58 + protected:
1.59 + // Returns the hosting HWND.
1.60 + HWND GetHWND() { return hwnd_; }
1.61 +
1.62 + // Invoked when the cursor first moves over the hwnd during a dnd session.
1.63 + // This should return a bitmask of the supported drop operations:
1.64 + // DROPEFFECT_NONE, DROPEFFECT_COPY, DROPEFFECT_LINK and/or
1.65 + // DROPEFFECT_MOVE.
1.66 + virtual DWORD OnDragEnter(IDataObject* data_object,
1.67 + DWORD key_state,
1.68 + POINT cursor_position,
1.69 + DWORD effect);
1.70 +
1.71 + // Invoked when the cursor moves over the window during a dnd session.
1.72 + // This should return a bitmask of the supported drop operations:
1.73 + // DROPEFFECT_NONE, DROPEFFECT_COPY, DROPEFFECT_LINK and/or
1.74 + // DROPEFFECT_MOVE.
1.75 + virtual DWORD OnDragOver(IDataObject* data_object,
1.76 + DWORD key_state,
1.77 + POINT cursor_position,
1.78 + DWORD effect);
1.79 +
1.80 + // Invoked when the cursor moves outside the bounds of the hwnd during a
1.81 + // dnd session.
1.82 + virtual void OnDragLeave(IDataObject* data_object);
1.83 +
1.84 + // Invoked when the drop ends on the window. This should return the operation
1.85 + // that was taken.
1.86 + virtual DWORD OnDrop(IDataObject* data_object,
1.87 + DWORD key_state,
1.88 + POINT cursor_position,
1.89 + DWORD effect);
1.90 +
1.91 + // Return the drag identity.
1.92 + static int32_t GetDragIdentity() { return drag_identity_; }
1.93 +
1.94 + private:
1.95 + // Returns the cached drop helper, creating one if necessary. The returned
1.96 + // object is not addrefed. May return NULL if the object couldn't be created.
1.97 + static IDropTargetHelper* DropHelper();
1.98 +
1.99 + // The data object currently being dragged over this drop target.
1.100 + scoped_refptr<IDataObject> current_data_object_;
1.101 +
1.102 + // A helper object that is used to provide drag image support while the mouse
1.103 + // is dragging over the content area.
1.104 + //
1.105 + // DO NOT ACCESS DIRECTLY! Use DropHelper() instead, which will lazily create
1.106 + // this if it doesn't exist yet. This object can take tens of milliseconds to
1.107 + // create, and we don't want to block any window opening for this, especially
1.108 + // since often, DnD will never be used. Instead, we force this penalty to the
1.109 + // first time it is actually used.
1.110 + static IDropTargetHelper* cached_drop_target_helper_;
1.111 +
1.112 + // The drag identity (id). An up-counter that increases when the cursor first
1.113 + // moves over the HWND in a DnD session (OnDragEnter). 0 is reserved to mean
1.114 + // the "no/unknown" identity, and is used for initialization. The identity is
1.115 + // sent to the renderer in drag enter notifications. Note: the identity value
1.116 + // is passed over the renderer NPAPI interface to gears, so use int32_t instead
1.117 + // of int here.
1.118 + static int32_t drag_identity_;
1.119 +
1.120 + // The HWND of the source. This HWND is used to determine coordinates for
1.121 + // mouse events that are sent to the renderer notifying various drag states.
1.122 + HWND hwnd_;
1.123 +
1.124 + // Whether or not we are currently processing drag notifications for drags
1.125 + // initiated in this window.
1.126 + bool suspend_;
1.127 +
1.128 + LONG ref_count_;
1.129 +
1.130 + DISALLOW_EVIL_CONSTRUCTORS(BaseDropTarget);
1.131 +};
1.132 +
1.133 +#endif // BASE_BASE_DROP_TARGET_H_
