pjs/widget/windows/nsNativeDragTarget.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Communicator client code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
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* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
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*
* ***** END LICENSE BLOCK ***** */
#include <stdio.h>
#include "nsIDragService.h"
#include "nsWidgetsCID.h"
#include "nsNativeDragTarget.h"
#include "nsDragService.h"
#include "nsIServiceManager.h"
#include "nsIDOMNode.h"
#include "nsCOMPtr.h"
#include "nsIWidget.h"
#include "nsWindow.h"
#include "nsClipboard.h"
/* Define Class IDs */
static NS_DEFINE_IID(kCDragServiceCID, NS_DRAGSERVICE_CID);
/* Define Interface IDs */
static NS_DEFINE_IID(kIDragServiceIID, NS_IDRAGSERVICE_IID);
// This is cached for Leave notification
static POINTL gDragLastPoint;
/*
* class nsNativeDragTarget
*/
nsNativeDragTarget::nsNativeDragTarget(nsIWidget * aWnd)
: m_cRef(0),
mEffectsAllowed(DROPEFFECT_MOVE | DROPEFFECT_COPY | DROPEFFECT_LINK),
mEffectsPreferred(DROPEFFECT_NONE),
mTookOwnRef(false), mWindow(aWnd), mDropTargetHelper(nsnull)
{
mHWnd = (HWND)mWindow->GetNativeData(NS_NATIVE_WINDOW);
/*
* Create/Get the DragService that we have implemented
*/
CallGetService(kCDragServiceCID, &mDragService);
// Drag target helper for drag image support
CoCreateInstance(CLSID_DragDropHelper, NULL, CLSCTX_INPROC_SERVER,
IID_IDropTargetHelper, (LPVOID*)&mDropTargetHelper);
}
nsNativeDragTarget::~nsNativeDragTarget()
{
NS_RELEASE(mDragService);
if (mDropTargetHelper) {
mDropTargetHelper->Release();
mDropTargetHelper = nsnull;
}
}
// IUnknown methods - see iunknown.h for documentation
STDMETHODIMP
nsNativeDragTarget::QueryInterface(REFIID riid, void** ppv)
{
*ppv=NULL;
if (IID_IUnknown == riid || IID_IDropTarget == riid)
*ppv=this;
if (NULL!=*ppv) {
((LPUNKNOWN)*ppv)->AddRef();
return S_OK;
}
return E_NOINTERFACE;
}
STDMETHODIMP_(ULONG)
nsNativeDragTarget::AddRef(void)
{
++m_cRef;
NS_LOG_ADDREF(this, m_cRef, "nsNativeDragTarget", sizeof(*this));
return m_cRef;
}
STDMETHODIMP_(ULONG) nsNativeDragTarget::Release(void)
{
--m_cRef;
NS_LOG_RELEASE(this, m_cRef, "nsNativeDragTarget");
if (0 != m_cRef)
return m_cRef;
delete this;
return 0;
}
void
nsNativeDragTarget::GetGeckoDragAction(DWORD grfKeyState, LPDWORD pdwEffect,
PRUint32 * aGeckoAction)
{
// If a window is disabled or a modal window is on top of it
// (which implies it is disabled), then we should not allow dropping.
bool isEnabled;
if (NS_SUCCEEDED(mWindow->IsEnabled(&isEnabled)) && !isEnabled) {
*pdwEffect = DROPEFFECT_NONE;
*aGeckoAction = nsIDragService::DRAGDROP_ACTION_NONE;
return;
}
// If the user explicitly uses a modifier key, they want the associated action
// Shift + Control -> LINK, Shift -> MOVE, Ctrl -> COPY
DWORD desiredEffect = DROPEFFECT_NONE;
if ((grfKeyState & MK_CONTROL) && (grfKeyState & MK_SHIFT)) {
desiredEffect = DROPEFFECT_LINK;
} else if (grfKeyState & MK_SHIFT) {
desiredEffect = DROPEFFECT_MOVE;
} else if (grfKeyState & MK_CONTROL) {
desiredEffect = DROPEFFECT_COPY;
}
// Determine the desired effect from what is allowed and preferred.
if (!(desiredEffect &= mEffectsAllowed)) {
// No modifier key effect is set which is also allowed, check
// the preference of the data.
desiredEffect = mEffectsPreferred & mEffectsAllowed;
if (!desiredEffect) {
// No preference is set, so just fall back to the allowed effect itself
desiredEffect = mEffectsAllowed;
}
}
// Otherwise we should specify the first available effect
// from MOVE, COPY, or LINK.
if (desiredEffect & DROPEFFECT_MOVE) {
*pdwEffect = DROPEFFECT_MOVE;
*aGeckoAction = nsIDragService::DRAGDROP_ACTION_MOVE;
} else if (desiredEffect & DROPEFFECT_COPY) {
*pdwEffect = DROPEFFECT_COPY;
*aGeckoAction = nsIDragService::DRAGDROP_ACTION_COPY;
} else if (desiredEffect & DROPEFFECT_LINK) {
*pdwEffect = DROPEFFECT_LINK;
*aGeckoAction = nsIDragService::DRAGDROP_ACTION_LINK;
} else {
*pdwEffect = DROPEFFECT_NONE;
*aGeckoAction = nsIDragService::DRAGDROP_ACTION_NONE;
}
}
inline
bool
IsKeyDown(char key)
{
return GetKeyState(key) < 0;
}
void
nsNativeDragTarget::DispatchDragDropEvent(PRUint32 aEventType, POINTL aPT)
{
nsEventStatus status;
nsDragEvent event(true, aEventType, mWindow);
nsWindow * win = static_cast<nsWindow *>(mWindow);
win->InitEvent(event);
POINT cpos;
cpos.x = aPT.x;
cpos.y = aPT.y;
if (mHWnd != NULL) {
::ScreenToClient(mHWnd, &cpos);
event.refPoint.x = cpos.x;
event.refPoint.y = cpos.y;
} else {
event.refPoint.x = 0;
event.refPoint.y = 0;
}
event.isShift = IsKeyDown(NS_VK_SHIFT);
event.isControl = IsKeyDown(NS_VK_CONTROL);
event.isMeta = false;
event.isAlt = IsKeyDown(NS_VK_ALT);
event.inputSource = static_cast<nsBaseDragService*>(mDragService)->GetInputSource();
mWindow->DispatchEvent(&event, status);
}
void
nsNativeDragTarget::ProcessDrag(PRUint32 aEventType,
DWORD grfKeyState,
POINTL ptl,
DWORD* pdwEffect)
{
// Before dispatching the event make sure we have the correct drop action set
PRUint32 geckoAction;
GetGeckoDragAction(grfKeyState, pdwEffect, &geckoAction);
// Set the current action into the Gecko specific type
nsCOMPtr<nsIDragSession> currSession;
mDragService->GetCurrentSession(getter_AddRefs(currSession));
if (!currSession) {
return;
}
currSession->SetDragAction(geckoAction);
// Dispatch the event into Gecko
DispatchDragDropEvent(aEventType, ptl);
if (aEventType != NS_DRAGDROP_DROP) {
// Get the cached drag effect from the drag service, the data member should
// have been set by whoever handled the nsGUIEvent or nsIDOMEvent on drags.
bool canDrop;
currSession->GetCanDrop(&canDrop);
if (!canDrop) {
*pdwEffect = DROPEFFECT_NONE;
}
}
// Clear the cached value
currSession->SetCanDrop(false);
}
// IDropTarget methods
STDMETHODIMP
nsNativeDragTarget::DragEnter(LPDATAOBJECT pIDataSource,
DWORD grfKeyState,
POINTL ptl,
DWORD* pdwEffect)
{
if (!mDragService) {
return E_FAIL;
}
mEffectsAllowed = *pdwEffect;
AddLinkSupportIfCanBeGenerated(pIDataSource);
// Drag and drop image helper
if (mDropTargetHelper) {
POINT pt = { ptl.x, ptl.y };
mDropTargetHelper->DragEnter(mHWnd, pIDataSource, &pt, *pdwEffect);
}
// save a ref to this, in case the window is destroyed underneath us
NS_ASSERTION(!mTookOwnRef, "own ref already taken!");
this->AddRef();
mTookOwnRef = true;
// tell the drag service about this drag (it may have come from an
// outside app).
mDragService->StartDragSession();
void* tempOutData = nsnull;
PRUint32 tempDataLen = 0;
nsresult loadResult = nsClipboard::GetNativeDataOffClipboard(
pIDataSource, 0, ::RegisterClipboardFormat(CFSTR_PREFERREDDROPEFFECT), nsnull, &tempOutData, &tempDataLen);
if (NS_SUCCEEDED(loadResult) && tempOutData) {
mEffectsPreferred = *((DWORD*)tempOutData);
nsMemory::Free(tempOutData);
} else {
// We have no preference if we can't obtain it
mEffectsPreferred = DROPEFFECT_NONE;
}
// Set the native data object into drag service
//
// This cast is ok because in the constructor we created a
// the actual implementation we wanted, so we know this is
// a nsDragService. It should be a private interface, though.
nsDragService * winDragService =
static_cast<nsDragService *>(mDragService);
winDragService->SetIDataObject(pIDataSource);
// Now process the native drag state and then dispatch the event
ProcessDrag(NS_DRAGDROP_ENTER, grfKeyState, ptl, pdwEffect);
return S_OK;
}
void
nsNativeDragTarget::AddLinkSupportIfCanBeGenerated(LPDATAOBJECT aIDataSource)
{
// If we don't have a link effect, but we can generate one, fix the
// drop effect to include it.
if (!(mEffectsAllowed & DROPEFFECT_LINK) && aIDataSource) {
if (S_OK == ::OleQueryLinkFromData(aIDataSource)) {
mEffectsAllowed |= DROPEFFECT_LINK;
}
}
}
STDMETHODIMP
nsNativeDragTarget::DragOver(DWORD grfKeyState,
POINTL ptl,
LPDWORD pdwEffect)
{
if (!mDragService) {
return E_FAIL;
}
// If a LINK effect could be generated previously from a DragEnter(),
// then we should include it as an allowed effect.
mEffectsAllowed = (*pdwEffect) | (mEffectsAllowed & DROPEFFECT_LINK);
nsCOMPtr<nsIDragSession> currentDragSession;
mDragService->GetCurrentSession(getter_AddRefs(currentDragSession));
if (!currentDragSession) {
return S_OK; // Drag was canceled.
}
// without the AddRef() |this| can get destroyed in an event handler
this->AddRef();
// Drag and drop image helper
if (mDropTargetHelper) {
POINT pt = { ptl.x, ptl.y };
mDropTargetHelper->DragOver(&pt, *pdwEffect);
}
mDragService->FireDragEventAtSource(NS_DRAGDROP_DRAG);
// Now process the native drag state and then dispatch the event
ProcessDrag(NS_DRAGDROP_OVER, grfKeyState, ptl, pdwEffect);
this->Release();
return S_OK;
}
STDMETHODIMP
nsNativeDragTarget::DragLeave()
{
if (!mDragService) {
return E_FAIL;
}
// Drag and drop image helper
if (mDropTargetHelper) {
mDropTargetHelper->DragLeave();
}
// dispatch the event into Gecko
DispatchDragDropEvent(NS_DRAGDROP_EXIT, gDragLastPoint);
nsCOMPtr<nsIDragSession> currentDragSession;
mDragService->GetCurrentSession(getter_AddRefs(currentDragSession));
if (currentDragSession) {
nsCOMPtr<nsIDOMNode> sourceNode;
currentDragSession->GetSourceNode(getter_AddRefs(sourceNode));
if (!sourceNode) {
// We're leaving a window while doing a drag that was
// initiated in a different app. End the drag session, since
// we're done with it for now (until the user drags back into
// mozilla).
mDragService->EndDragSession(false);
}
}
// release the ref that was taken in DragEnter
NS_ASSERTION(mTookOwnRef, "want to release own ref, but not taken!");
if (mTookOwnRef) {
this->Release();
mTookOwnRef = false;
}
return S_OK;
}
void
nsNativeDragTarget::DragCancel()
{
// Cancel the drag session if we did DragEnter.
if (mTookOwnRef) {
if (mDropTargetHelper) {
mDropTargetHelper->DragLeave();
}
if (mDragService) {
mDragService->EndDragSession(false);
}
this->Release(); // matching the AddRef in DragEnter
mTookOwnRef = false;
}
}
STDMETHODIMP
nsNativeDragTarget::Drop(LPDATAOBJECT pData,
DWORD grfKeyState,
POINTL aPT,
LPDWORD pdwEffect)
{
if (!mDragService) {
return E_FAIL;
}
mEffectsAllowed = *pdwEffect;
AddLinkSupportIfCanBeGenerated(pData);
// Drag and drop image helper
if (mDropTargetHelper) {
POINT pt = { aPT.x, aPT.y };
mDropTargetHelper->Drop(pData, &pt, *pdwEffect);
}
// Set the native data object into the drag service
//
// This cast is ok because in the constructor we created a
// the actual implementation we wanted, so we know this is
// a nsDragService (but it should still be a private interface)
nsDragService* winDragService = static_cast<nsDragService*>(mDragService);
winDragService->SetIDataObject(pData);
// NOTE: ProcessDrag spins the event loop which may destroy arbitrary objects.
// We use strong refs to prevent it from destroying these:
nsRefPtr<nsNativeDragTarget> kungFuDeathGrip = this;
nsCOMPtr<nsIDragService> serv = mDragService;
// Now process the native drag state and then dispatch the event
ProcessDrag(NS_DRAGDROP_DROP, grfKeyState, aPT, pdwEffect);
nsCOMPtr<nsIDragSession> currentDragSession;
serv->GetCurrentSession(getter_AddRefs(currentDragSession));
if (!currentDragSession) {
return S_OK; // DragCancel() was called.
}
// Let the win drag service know whether this session experienced
// a drop event within the application. Drop will not oocur if the
// drop landed outside the app. (used in tab tear off, bug 455884)
winDragService->SetDroppedLocal();
// tell the drag service we're done with the session
// Use GetMessagePos to get the position of the mouse at the last message
// seen by the event loop. (Bug 489729)
DWORD pos = ::GetMessagePos();
POINT cpos;
cpos.x = GET_X_LPARAM(pos);
cpos.y = GET_Y_LPARAM(pos);
winDragService->SetDragEndPoint(nsIntPoint(cpos.x, cpos.y));
serv->EndDragSession(true);
// release the ref that was taken in DragEnter
NS_ASSERTION(mTookOwnRef, "want to release own ref, but not taken!");
if (mTookOwnRef) {
this->Release();
mTookOwnRef = false;
}
return S_OK;
}