1 // Copyright (c) 2011 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 #include "ui/base/dragdrop/drop_target_win.h"
6
7 #include <shlobj.h>
8
9 #include "base/logging.h"
10
11 namespace ui {
12
13 IDropTargetHelper* DropTargetWin::cached_drop_target_helper_ = NULL;
14
DropTargetWin(HWND hwnd)15 DropTargetWin::DropTargetWin(HWND hwnd)
16 : hwnd_(hwnd),
17 ref_count_(0) {
18 DCHECK(hwnd);
19 HRESULT result = RegisterDragDrop(hwnd, this);
20 DCHECK(SUCCEEDED(result));
21 }
22
~DropTargetWin()23 DropTargetWin::~DropTargetWin() {
24 }
25
26 // static
DropHelper()27 IDropTargetHelper* DropTargetWin::DropHelper() {
28 if (!cached_drop_target_helper_) {
29 CoCreateInstance(CLSID_DragDropHelper, 0, CLSCTX_INPROC_SERVER,
30 IID_IDropTargetHelper,
31 reinterpret_cast<void**>(&cached_drop_target_helper_));
32 }
33 return cached_drop_target_helper_;
34 }
35
36 ///////////////////////////////////////////////////////////////////////////////
37 // DropTargetWin, IDropTarget implementation:
38
DragEnter(IDataObject * data_object,DWORD key_state,POINTL cursor_position,DWORD * effect)39 HRESULT DropTargetWin::DragEnter(IDataObject* data_object,
40 DWORD key_state,
41 POINTL cursor_position,
42 DWORD* effect) {
43 // Tell the helper that we entered so it can update the drag image.
44 IDropTargetHelper* drop_helper = DropHelper();
45 if (drop_helper) {
46 drop_helper->DragEnter(GetHWND(), data_object,
47 reinterpret_cast<POINT*>(&cursor_position), *effect);
48 }
49
50 current_data_object_ = data_object;
51 POINT screen_pt = { cursor_position.x, cursor_position.y };
52 *effect = OnDragEnter(current_data_object_, key_state, screen_pt, *effect);
53 return S_OK;
54 }
55
DragOver(DWORD key_state,POINTL cursor_position,DWORD * effect)56 HRESULT DropTargetWin::DragOver(DWORD key_state,
57 POINTL cursor_position,
58 DWORD* effect) {
59 // Tell the helper that we moved over it so it can update the drag image.
60 IDropTargetHelper* drop_helper = DropHelper();
61 if (drop_helper)
62 drop_helper->DragOver(reinterpret_cast<POINT*>(&cursor_position), *effect);
63
64 POINT screen_pt = { cursor_position.x, cursor_position.y };
65 *effect = OnDragOver(current_data_object_, key_state, screen_pt, *effect);
66 return S_OK;
67 }
68
DragLeave()69 HRESULT DropTargetWin::DragLeave() {
70 // Tell the helper that we moved out of it so it can update the drag image.
71 IDropTargetHelper* drop_helper = DropHelper();
72 if (drop_helper)
73 drop_helper->DragLeave();
74
75 OnDragLeave(current_data_object_);
76
77 current_data_object_ = NULL;
78 return S_OK;
79 }
80
Drop(IDataObject * data_object,DWORD key_state,POINTL cursor_position,DWORD * effect)81 HRESULT DropTargetWin::Drop(IDataObject* data_object,
82 DWORD key_state,
83 POINTL cursor_position,
84 DWORD* effect) {
85 // Tell the helper that we dropped onto it so it can update the drag image.
86 IDropTargetHelper* drop_helper = DropHelper();
87 if (drop_helper) {
88 drop_helper->Drop(current_data_object_,
89 reinterpret_cast<POINT*>(&cursor_position), *effect);
90 }
91
92 POINT screen_pt = { cursor_position.x, cursor_position.y };
93 *effect = OnDrop(current_data_object_, key_state, screen_pt, *effect);
94 return S_OK;
95 }
96
97 ///////////////////////////////////////////////////////////////////////////////
98 // DropTargetWin, IUnknown implementation:
99
QueryInterface(const IID & iid,void ** object)100 HRESULT DropTargetWin::QueryInterface(const IID& iid, void** object) {
101 *object = NULL;
102 if (IsEqualIID(iid, IID_IUnknown) || IsEqualIID(iid, IID_IDropTarget)) {
103 *object = this;
104 } else {
105 return E_NOINTERFACE;
106 }
107 AddRef();
108 return S_OK;
109 }
110
AddRef()111 ULONG DropTargetWin::AddRef() {
112 return ++ref_count_;
113 }
114
Release()115 ULONG DropTargetWin::Release() {
116 if (--ref_count_ == 0) {
117 delete this;
118 return 0U;
119 }
120 return ref_count_;
121 }
122
OnDragEnter(IDataObject * data_object,DWORD key_state,POINT cursor_position,DWORD effect)123 DWORD DropTargetWin::OnDragEnter(IDataObject* data_object,
124 DWORD key_state,
125 POINT cursor_position,
126 DWORD effect) {
127 return DROPEFFECT_NONE;
128 }
129
OnDragOver(IDataObject * data_object,DWORD key_state,POINT cursor_position,DWORD effect)130 DWORD DropTargetWin::OnDragOver(IDataObject* data_object,
131 DWORD key_state,
132 POINT cursor_position,
133 DWORD effect) {
134 return DROPEFFECT_NONE;
135 }
136
OnDragLeave(IDataObject * data_object)137 void DropTargetWin::OnDragLeave(IDataObject* data_object) {
138 }
139
OnDrop(IDataObject * data_object,DWORD key_state,POINT cursor_position,DWORD effect)140 DWORD DropTargetWin::OnDrop(IDataObject* data_object,
141 DWORD key_state,
142 POINT cursor_position,
143 DWORD effect) {
144 return DROPEFFECT_NONE;
145 }
146
147 } // namespace ui
148