Move BaseDropTarget and BaseDragSource from base to app/win. Remove the "Base" class name prefix and put in the app::win namespace.

TEST=none
BUG=none
Review URL: http://codereview.chromium.org/3822007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@62900 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 425 insertions, 0 deletions

diff --git a/app/win/drag_source.cc b/app/win/drag_source.cc
new file mode 100644
index 0000000..a695a33
--- /dev/null
+++ b/app/win/drag_source.cc
@@ -0,0 +1,57 @@
+// Copyright (c) 2010 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 "app/win/drag_source.h"
+
+namespace app {
+namespace win {
+
+DragSource::DragSource() : cancel_drag_(false) {
+}
+
+HRESULT DragSource::QueryContinueDrag(BOOL escape_pressed, DWORD key_state) {
+  if (cancel_drag_)
+    return DRAGDROP_S_CANCEL;
+
+  if (escape_pressed) {
+    OnDragSourceCancel();
+    return DRAGDROP_S_CANCEL;
+  }
+
+  if (!(key_state & MK_LBUTTON)) {
+    OnDragSourceDrop();
+    return DRAGDROP_S_DROP;
+  }
+
+  OnDragSourceMove();
+  return S_OK;
+}
+
+HRESULT DragSource::GiveFeedback(DWORD effect) {
+  return DRAGDROP_S_USEDEFAULTCURSORS;
+}
+
+HRESULT DragSource::QueryInterface(const IID& iid, void** object) {
+  *object = NULL;
+  if (IsEqualIID(iid, IID_IUnknown) || IsEqualIID(iid, IID_IDropSource)) {
+    *object = this;
+  } else {
+    return E_NOINTERFACE;
+  }
+  AddRef();
+  return S_OK;
+}
+
+ULONG DragSource::AddRef() {
+  base::RefCountedThreadSafe<DragSource>::AddRef();
+  return 0;
+}
+
+ULONG DragSource::Release() {
+  base::RefCountedThreadSafe<DragSource>::Release();
+  return 0;
+}
+
+}  // namespace win
+}  // namespace app
diff --git a/app/win/drag_source.h b/app/win/drag_source.h
new file mode 100644
index 0000000..75bee86
--- /dev/null
+++ b/app/win/drag_source.h
@@ -0,0 +1,58 @@
+// Copyright (c) 2010 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.
+
+#ifndef APP_WIN_DRAG_SOURCE_H_
+#define APP_WIN_DRAG_SOURCE_H_
+#pragma once
+
+#include <objidl.h>
+
+#include "base/basictypes.h"
+#include "base/ref_counted.h"
+
+namespace app {
+namespace win {
+
+// A base IDropSource implementation. Handles notifications sent by an active
+// drag-drop operation as the user mouses over other drop targets on their
+// system. This object tells Windows whether or not the drag should continue,
+// and supplies the appropriate cursors.
+class DragSource : public IDropSource,
+                   public base::RefCountedThreadSafe<DragSource> {
+ public:
+  DragSource();
+  virtual ~DragSource() {}
+
+  // Stop the drag operation at the next chance we get.  This doesn't
+  // synchronously stop the drag (since Windows is controlling that),
+  // but lets us tell Windows to cancel the drag the next chance we get.
+  void CancelDrag() {
+    cancel_drag_ = true;
+  }
+
+  // IDropSource implementation:
+  HRESULT __stdcall QueryContinueDrag(BOOL escape_pressed, DWORD key_state);
+  HRESULT __stdcall GiveFeedback(DWORD effect);
+
+  // IUnknown implementation:
+  HRESULT __stdcall QueryInterface(const IID& iid, void** object);
+  ULONG __stdcall AddRef();
+  ULONG __stdcall Release();
+
+ protected:
+  virtual void OnDragSourceCancel() {}
+  virtual void OnDragSourceDrop() {}
+  virtual void OnDragSourceMove() {}
+
+ private:
+  // Set to true if we want to cancel the drag operation.
+  bool cancel_drag_;
+
+  DISALLOW_COPY_AND_ASSIGN(DragSource);
+};
+
+}  // namespace win
+}  // namespace app
+
+#endif  // APP_WIN_DRAG_SOURCE_H_
diff --git a/app/win/drop_target.cc b/app/win/drop_target.cc
new file mode 100644
index 0000000..6742e19
--- /dev/null
+++ b/app/win/drop_target.cc
@@ -0,0 +1,174 @@
+// Copyright (c) 2010 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 "app/win/drop_target.h"
+
+#include <shlobj.h>
+
+#include "base/logging.h"
+
+namespace app {
+namespace win {
+
+IDropTargetHelper* DropTarget::cached_drop_target_helper_ = NULL;
+int32 DropTarget::drag_identity_ = 0;
+
+DropTarget::DropTarget(HWND hwnd)
+    : hwnd_(hwnd),
+      suspended_(false),
+      ref_count_(0) {
+  DCHECK(hwnd);
+  HRESULT result = RegisterDragDrop(hwnd, this);
+  DCHECK(SUCCEEDED(result));
+}
+
+DropTarget::~DropTarget() {
+}
+
+// static
+IDropTargetHelper* DropTarget::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_;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// DropTarget, IDropTarget implementation:
+
+HRESULT DropTarget::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 (suspended_) {
+    *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 DropTarget::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 (suspended_) {
+    *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 DropTarget::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();
+
+  if (suspended_)
+    return S_OK;
+
+  OnDragLeave(current_data_object_);
+
+  current_data_object_ = NULL;
+  return S_OK;
+}
+
+HRESULT DropTarget::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 (suspended_) {
+    *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;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// DropTarget, IUnknown implementation:
+
+HRESULT DropTarget::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 DropTarget::AddRef() {
+  return ++ref_count_;
+}
+
+ULONG DropTarget::Release() {
+  if (--ref_count_ == 0) {
+    delete this;
+    return 0U;
+  }
+  return ref_count_;
+}
+
+DWORD DropTarget::OnDragEnter(IDataObject* data_object,
+                              DWORD key_state,
+                              POINT cursor_position,
+                              DWORD effect) {
+  return DROPEFFECT_NONE;
+}
+
+DWORD DropTarget::OnDragOver(IDataObject* data_object,
+                             DWORD key_state,
+                             POINT cursor_position,
+                             DWORD effect) {
+  return DROPEFFECT_NONE;
+}
+
+void DropTarget::OnDragLeave(IDataObject* data_object) {
+}
+
+DWORD DropTarget::OnDrop(IDataObject* data_object,
+                         DWORD key_state,
+                         POINT cursor_position,
+                         DWORD effect) {
+  return DROPEFFECT_NONE;
+}
+
+}  // namespace win
+}  // namespace app
diff --git a/app/win/drop_target.h b/app/win/drop_target.h
new file mode 100644
index 0000000..e7dc1ec
--- /dev/null
+++ b/app/win/drop_target.h
@@ -0,0 +1,136 @@
+// Copyright (c) 2010 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.
+
+#ifndef APP_WIN_DROP_TARGET_H_
+#define APP_WIN_DROP_TARGET_H_
+#pragma once
+
+#include <objidl.h>
+
+#include "base/ref_counted.h"
+
+// Windows interface.
+struct IDropTargetHelper;
+
+namespace app {
+namespace win {
+
+// A DropTarget implementation that takes care of the nitty gritty
+// of dnd. While this class is concrete, subclasses will most likely
+// want to override various OnXXX methods.
+//
+// Because DropTarget is ref counted you shouldn't delete it directly,
+// rather wrap it in a scoped_refptr. Be sure and invoke RevokeDragDrop(m_hWnd)
+// before the HWND is deleted too.
+//
+// This class is meant to be used in a STA and is not multithread-safe.
+class DropTarget : public IDropTarget {
+ public:
+  // Create a new DropTarget associating it with the given HWND.
+  explicit DropTarget(HWND hwnd);
+  virtual ~DropTarget();
+
+  // When suspended is set to |true|, the drop target does not receive drops
+  // from drags initiated within the owning HWND.
+  bool suspended() const { return suspended_; }
+  void set_suspended(bool suspended) { suspended_ = suspended; }
+
+  // IDropTarget implementation:
+  HRESULT __stdcall DragEnter(IDataObject* data_object,
+                              DWORD key_state,
+                              POINTL cursor_position,
+                              DWORD* effect);
+  HRESULT __stdcall DragOver(DWORD key_state,
+                             POINTL cursor_position,
+                             DWORD* effect);
+  HRESULT __stdcall DragLeave();
+  HRESULT __stdcall Drop(IDataObject* data_object,
+                         DWORD key_state,
+                         POINTL cursor_position,
+                         DWORD* effect);
+
+  // IUnknown implementation:
+  HRESULT __stdcall QueryInterface(const IID& iid, void** object);
+  ULONG __stdcall AddRef();
+  ULONG __stdcall Release();
+
+ protected:
+  // Returns the hosting HWND.
+  HWND GetHWND() { return hwnd_; }
+
+  // Invoked when the cursor first moves over the hwnd during a dnd session.
+  // This should return a bitmask of the supported drop operations:
+  // DROPEFFECT_NONE, DROPEFFECT_COPY, DROPEFFECT_LINK and/or
+  // DROPEFFECT_MOVE.
+  virtual DWORD OnDragEnter(IDataObject* data_object,
+                            DWORD key_state,
+                            POINT cursor_position,
+                            DWORD effect);
+
+  // Invoked when the cursor moves over the window during a dnd session.
+  // This should return a bitmask of the supported drop operations:
+  // DROPEFFECT_NONE, DROPEFFECT_COPY, DROPEFFECT_LINK and/or
+  // DROPEFFECT_MOVE.
+  virtual DWORD OnDragOver(IDataObject* data_object,
+                           DWORD key_state,
+                           POINT cursor_position,
+                           DWORD effect);
+
+  // Invoked when the cursor moves outside the bounds of the hwnd during a
+  // dnd session.
+  virtual void OnDragLeave(IDataObject* data_object);
+
+  // Invoked when the drop ends on the window. This should return the operation
+  // that was taken.
+  virtual DWORD OnDrop(IDataObject* data_object,
+                       DWORD key_state,
+                       POINT cursor_position,
+                       DWORD effect);
+
+  // Return the drag identity.
+  static int32 GetDragIdentity() { return drag_identity_; }
+
+ private:
+  // Returns the cached drop helper, creating one if necessary. The returned
+  // object is not addrefed. May return NULL if the object couldn't be created.
+  static IDropTargetHelper* DropHelper();
+
+  // The data object currently being dragged over this drop target.
+  scoped_refptr<IDataObject> current_data_object_;
+
+  // A helper object that is used to provide drag image support while the mouse
+  // is dragging over the content area.
+  //
+  // DO NOT ACCESS DIRECTLY! Use DropHelper() instead, which will lazily create
+  // this if it doesn't exist yet. This object can take tens of milliseconds to
+  // create, and we don't want to block any window opening for this, especially
+  // since often, DnD will never be used. Instead, we force this penalty to the
+  // first time it is actually used.
+  static IDropTargetHelper* cached_drop_target_helper_;
+
+  // The drag identity (id). An up-counter that increases when the cursor first
+  // moves over the HWND in a DnD session (OnDragEnter). 0 is reserved to mean
+  // the "no/unknown" identity, and is used for initialization. The identity is
+  // sent to the renderer in drag enter notifications. Note: the identity value
+  // is passed over the renderer NPAPI interface to gears, so use int32 instead
+  // of int here.
+  static int32 drag_identity_;
+
+  // The HWND of the source. This HWND is used to determine coordinates for
+  // mouse events that are sent to the renderer notifying various drag states.
+  HWND hwnd_;
+
+  // Whether or not we are currently processing drag notifications for drags
+  // initiated in this window.
+  bool suspended_;
+
+  LONG ref_count_;
+
+  DISALLOW_COPY_AND_ASSIGN(DropTarget);
+};
+
+}  // namespace win
+}  // namespace app
+
+#endif  // APP_WIN_DROP_TARGET_H_