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// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/base_drop_target.h"
#include <shlobj.h>
#include "base/logging.h"
///////////////////////////////////////////////////////////////////////////////
IDropTargetHelper* BaseDropTarget::cached_drop_target_helper_ = NULL;
int32 BaseDropTarget::drag_identity_ = 0;
BaseDropTarget::BaseDropTarget(HWND hwnd)
: hwnd_(hwnd),
suspend_(false),
ref_count_(0) {
DCHECK(hwnd);
HRESULT result = RegisterDragDrop(hwnd, this);
DCHECK(SUCCEEDED(result));
}
BaseDropTarget::~BaseDropTarget() {
}
// static
IDropTargetHelper* BaseDropTarget::DropHelper() {
if (!cached_drop_target_helper_) {
CoCreateInstance(CLSID_DragDropHelper, 0, CLSCTX_INPROC_SERVER,
IID_IDropTargetHelper,
reinterpret_cast<void**>(&cached_drop_target_helper_));
}
return cached_drop_target_helper_;
}
///////////////////////////////////////////////////////////////////////////////
// BaseDropTarget, IDropTarget implementation:
HRESULT BaseDropTarget::DragEnter(IDataObject* data_object,
DWORD key_state,
POINTL cursor_position,
DWORD* effect) {
// Tell the helper that we entered so it can update the drag image.
IDropTargetHelper* drop_helper = DropHelper();
if (drop_helper) {
drop_helper->DragEnter(GetHWND(), data_object,
reinterpret_cast<POINT*>(&cursor_position), *effect);
}
// You can't drag and drop within the same HWND.
if (suspend_) {
*effect = DROPEFFECT_NONE;
return S_OK;
}
// Update the drag identity, skipping 0.
if (++drag_identity_ == 0)
++drag_identity_;
current_data_object_ = data_object;
POINT screen_pt = { cursor_position.x, cursor_position.y };
*effect = OnDragEnter(current_data_object_, key_state, screen_pt, *effect);
return S_OK;
}
HRESULT BaseDropTarget::DragOver(DWORD key_state,
POINTL cursor_position,
DWORD* effect) {
// Tell the helper that we moved over it so it can update the drag image.
IDropTargetHelper* drop_helper = DropHelper();
if (drop_helper)
drop_helper->DragOver(reinterpret_cast<POINT*>(&cursor_position), *effect);
if (suspend_) {
*effect = DROPEFFECT_NONE;
return S_OK;
}
POINT screen_pt = { cursor_position.x, cursor_position.y };
*effect = OnDragOver(current_data_object_, key_state, screen_pt, *effect);
return S_OK;
}
HRESULT BaseDropTarget::DragLeave() {
// Tell the helper that we moved out of it so it can update the drag image.
IDropTargetHelper* drop_helper = DropHelper();
if (drop_helper)
drop_helper->DragLeave();
OnDragLeave(current_data_object_);
current_data_object_ = NULL;
return S_OK;
}
HRESULT BaseDropTarget::Drop(IDataObject* data_object,
DWORD key_state,
POINTL cursor_position,
DWORD* effect) {
// Tell the helper that we dropped onto it so it can update the drag image.
IDropTargetHelper* drop_helper = DropHelper();
if (drop_helper) {
drop_helper->Drop(current_data_object_,
reinterpret_cast<POINT*>(&cursor_position), *effect);
}
if (suspend_) {
*effect = DROPEFFECT_NONE;
return S_OK;
}
POINT screen_pt = { cursor_position.x, cursor_position.y };
*effect = OnDrop(current_data_object_, key_state, screen_pt, *effect);
return S_OK;
}
///////////////////////////////////////////////////////////////////////////////
// BaseDropTarget, IUnknown implementation:
HRESULT BaseDropTarget::QueryInterface(const IID& iid, void** object) {
*object = NULL;
if (IsEqualIID(iid, IID_IUnknown) || IsEqualIID(iid, IID_IDropTarget)) {
*object = this;
} else {
return E_NOINTERFACE;
}
AddRef();
return S_OK;
}
ULONG BaseDropTarget::AddRef() {
return ++ref_count_;
}
ULONG BaseDropTarget::Release() {
if (--ref_count_ == 0) {
delete this;
return 0U;
}
return ref_count_;
}
DWORD BaseDropTarget::OnDragEnter(IDataObject* data_object,
DWORD key_state,
POINT cursor_position,
DWORD effect) {
return DROPEFFECT_NONE;
}
DWORD BaseDropTarget::OnDragOver(IDataObject* data_object,
DWORD key_state,
POINT cursor_position,
DWORD effect) {
return DROPEFFECT_NONE;
}
void BaseDropTarget::OnDragLeave(IDataObject* data_object) {
}
DWORD BaseDropTarget::OnDrop(IDataObject* data_object,
DWORD key_state,
POINT cursor_position,
DWORD effect) {
return DROPEFFECT_NONE;
}
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