1 files changed, 472 insertions, 0 deletions
diff --git a/widget/windows/nsNativeDragTarget.cpp b/widget/windows/nsNativeDragTarget.cpp
new file mode 100644
index 0000000000..b615a3e4bc
--- /dev/null
+++ b/widget/windows/nsNativeDragTarget.cpp
@@ -0,0 +1,472 @@
+/* -*- 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
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#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
+    // DragOver calls, see bug 1465513. It looks like this might be because
+    // 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
+  // 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));
+  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;
+}