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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#include <stdio.h>
#include "nsIDragService.h"
#include "nsWidgetsCID.h"
#include "nsNativeDragTarget.h"
#include "nsDragService.h"
#include "nsINode.h"
#include "nsCOMPtr.h"
#include "nsIWidget.h"
#include "nsWindow.h"
#include "nsClipboard.h"
#include "KeyboardLayout.h"
#include "mozilla/MouseEvents.h"
using namespace mozilla;
using namespace mozilla::widget;
// This is cached for Leave notification
static POINTL gDragLastPoint;
bool nsNativeDragTarget::gDragImageChanged = false;
/*
* class nsNativeDragTarget
*/
nsNativeDragTarget::nsNativeDragTarget(nsIWidget* aWidget)
: m_cRef(0),
mEffectsAllowed(DROPEFFECT_MOVE | DROPEFFECT_COPY | DROPEFFECT_LINK),
mEffectsPreferred(DROPEFFECT_NONE),
mTookOwnRef(false),
mWidget(aWidget),
mDropTargetHelper(nullptr) {
mHWnd = (HWND)mWidget->GetNativeData(NS_NATIVE_WINDOW);
mDragService = do_GetService("@mozilla.org/widget/dragservice;1");
}
nsNativeDragTarget::~nsNativeDragTarget() {
if (mDropTargetHelper) {
mDropTargetHelper->Release();
mDropTargetHelper = nullptr;
}
}
// IUnknown methods - see iunknown.h for documentation
STDMETHODIMP
nsNativeDragTarget::QueryInterface(REFIID riid, void** ppv) {
*ppv = nullptr;
if (IID_IUnknown == riid || IID_IDropTarget == riid) *ppv = this;
if (nullptr != *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,
uint32_t* 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.
if (!mWidget->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(EventMessage aEventMessage,
const POINTL& aPT) {
WidgetDragEvent event(true, aEventMessage, mWidget);
nsWindow* win = static_cast<nsWindow*>(mWidget);
win->InitEvent(event);
POINT cpos;
cpos.x = aPT.x;
cpos.y = aPT.y;
if (mHWnd != nullptr) {
::ScreenToClient(mHWnd, &cpos);
event.mRefPoint = LayoutDeviceIntPoint(cpos.x, cpos.y);
} else {
event.mRefPoint = LayoutDeviceIntPoint(0, 0);
}
ModifierKeyState modifierKeyState;
modifierKeyState.InitInputEvent(event);
event.mInputSource =
static_cast<nsBaseDragService*>(mDragService.get())->GetInputSource();
mWidget->DispatchInputEvent(&event);
}
void nsNativeDragTarget::ProcessDrag(EventMessage aEventMessage,
DWORD grfKeyState, POINTL ptl,
DWORD* pdwEffect) {
// Before dispatching the event make sure we have the correct drop action set
uint32_t 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(aEventMessage, ptl);
// If TakeChildProcessDragAction returns something other than
// DRAGDROP_ACTION_UNINITIALIZED, it means that the last event was sent
// to the child process and this event is also being sent to the child
// process. In this case, use the last event's action instead.
nsDragService* dragService = static_cast<nsDragService*>(mDragService.get());
currSession->GetDragAction(&geckoAction);
int32_t childDragAction = dragService->TakeChildProcessDragAction();
if (childDragAction != nsIDragService::DRAGDROP_ACTION_UNINITIALIZED) {
geckoAction = childDragAction;
}
if (nsIDragService::DRAGDROP_ACTION_LINK & geckoAction) {
*pdwEffect = DROPEFFECT_LINK;
} else if (nsIDragService::DRAGDROP_ACTION_COPY & geckoAction) {
*pdwEffect = DROPEFFECT_COPY;
} else if (nsIDragService::DRAGDROP_ACTION_MOVE & geckoAction) {
*pdwEffect = DROPEFFECT_MOVE;
} else {
*pdwEffect = DROPEFFECT_NONE;
}
if (aEventMessage != eDrop) {
// Get the cached drag effect from the drag service, the data member should
// have been set by whoever handled the WidgetGUIEvent 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 (GetDropTargetHelper()) {
// We get a lot of crashes (often uncaught by our handler) later on during
// we're not cleaning up previous drags fully and now released resources get
// used. Calling IDropTargetHelper::DragLeave before DragEnter seems to fix
// this for at least one reproduction of this crash.
GetDropTargetHelper()->DragLeave();
POINT pt = {ptl.x, ptl.y};
GetDropTargetHelper()->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 = nullptr;
uint32_t tempDataLen = 0;
nsresult loadResult = nsClipboard::GetNativeDataOffClipboard(
pIDataSource, 0, ::RegisterClipboardFormat(CFSTR_PREFERREDDROPEFFECT),
nullptr, &tempOutData, &tempDataLen);
if (NS_SUCCEEDED(loadResult) && tempOutData) {
mEffectsPreferred = *((DWORD*)tempOutData);
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.get());
winDragService->SetIDataObject(pIDataSource);
// Now process the native drag state and then dispatch the event
ProcessDrag(eDragEnter, 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;
}
bool dragImageChanged = gDragImageChanged;
gDragImageChanged = false;
// 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 (GetDropTargetHelper()) {
if (dragImageChanged) {
// See comment in nsNativeDragTarget::DragEnter.
GetDropTargetHelper()->DragLeave();
// The drop helper only updates the image during DragEnter, so emulate
// a DragEnter if the image was changed.
POINT pt = {ptl.x, ptl.y};
nsDragService* dragService =
static_cast<nsDragService*>(mDragService.get());
GetDropTargetHelper()->DragEnter(mHWnd, dragService->GetDataObject(), &pt,
*pdwEffect);
}
POINT pt = {ptl.x, ptl.y};
GetDropTargetHelper()->DragOver(&pt, *pdwEffect);
}
ModifierKeyState modifierKeyState;
nsCOMPtr<nsIDragService> dragService = mDragService;
dragService->FireDragEventAtSource(eDrag, modifierKeyState.GetModifiers());
// Now process the native drag state and then dispatch the event
ProcessDrag(eDragOver, grfKeyState, ptl, pdwEffect);
this->Release();
return S_OK;
}
STDMETHODIMP
nsNativeDragTarget::DragLeave() {
if (!mDragService) {
return E_FAIL;
}
// Drag and drop image helper
if (GetDropTargetHelper()) {
GetDropTargetHelper()->DragLeave();
}
// dispatch the event into Gecko
DispatchDragDropEvent(eDragExit, gDragLastPoint);
nsCOMPtr<nsIDragSession> currentDragSession;
mDragService->GetCurrentSession(getter_AddRefs(currentDragSession));
if (currentDragSession) {
nsCOMPtr<nsINode> 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).
ModifierKeyState modifierKeyState;
nsCOMPtr<nsIDragService> dragService = mDragService;
dragService->EndDragSession(false, modifierKeyState.GetModifiers());
}
}
// 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 (GetDropTargetHelper()) {
GetDropTargetHelper()->DragLeave();
}
if (mDragService) {
ModifierKeyState modifierKeyState;
nsCOMPtr<nsIDragService> dragService = mDragService;
dragService->EndDragSession(false, modifierKeyState.GetModifiers());
}
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 (GetDropTargetHelper()) {
POINT pt = {aPT.x, aPT.y};
GetDropTargetHelper()->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.get());
winDragService->SetIDataObject(pData);
// NOTE: ProcessDrag spins the event loop which may destroy arbitrary objects.
// We use strong refs to prevent it from destroying these:
RefPtr<nsNativeDragTarget> kungFuDeathGrip = this;
nsCOMPtr<nsIDragService> serv = mDragService;
// Now process the native drag state and then dispatch the event
ProcessDrag(eDrop, 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
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
DWORD pos = ::GetMessagePos();
POINT cpos;
cpos.x = GET_X_LPARAM(pos);
cpos.y = GET_Y_LPARAM(pos);
winDragService->SetDragEndPoint(nsIntPoint(cpos.x, cpos.y));
ModifierKeyState modifierKeyState;
serv->EndDragSession(true, modifierKeyState.GetModifiers());
// 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;
}
/**
* By lazy loading mDropTargetHelper we save 50-70ms of startup time
* which is ~5% of startup time.
*/
IDropTargetHelper* nsNativeDragTarget::GetDropTargetHelper() {
if (!mDropTargetHelper) {
CoCreateInstance(CLSID_DragDropHelper, nullptr, CLSCTX_INPROC_SERVER,
IID_IDropTargetHelper, (LPVOID*)&mDropTargetHelper);
}
return mDropTargetHelper;
}