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// Copyright 2008, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include <windows.h>
#include <shlobj.h>
#include "base/base_drop_target.h"
#include "base/logging.h"
///////////////////////////////////////////////////////////////////////////////
IDropTargetHelper* BaseDropTarget::cached_drop_target_helper_ = NULL;
BaseDropTarget::BaseDropTarget(HWND hwnd)
: suspend_(false),
ref_count_(0),
hwnd_(hwnd) {
DCHECK(hwnd);
HRESULT result = RegisterDragDrop(hwnd, this);
}
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;
}
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 InterlockedIncrement(&ref_count_);
}
ULONG BaseDropTarget::Release() {
if (InterlockedDecrement(&ref_count_) == 0) {
ULONG copied_refcnt = ref_count_;
delete this;
return copied_refcnt;
}
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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