Add drag and drop support for Windows (issue #140).

git-svn-id: https://chromiumembedded.googlecode.com/svn/trunk@194 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

libcef/web_drag_source_win.cc

@@ -0,0 +1,100 @@
+// Copyright (c) 2011 The Chromium Embedded Framework Authors.
+// Portions 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 "web_drag_source_win.h"
+#include "web_drag_utils_win.h"
+#include "cef_thread.h"
+
+#include "base/task.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebPoint.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebView.h"
+
+using WebKit::WebDragOperationNone;
+using WebKit::WebPoint;
+using WebKit::WebView;
+
+namespace {
+
+static void GetCursorPositions(gfx::NativeWindow wnd, gfx::Point* client,
+                               gfx::Point* screen) {
+  POINT cursor_pos;
+  GetCursorPos(&cursor_pos);
+  screen->SetPoint(cursor_pos.x, cursor_pos.y);
+  ScreenToClient(wnd, &cursor_pos);
+  client->SetPoint(cursor_pos.x, cursor_pos.y);
+}
+
+}  // namespace
+
+///////////////////////////////////////////////////////////////////////////////
+// WebDragSource, public:
+
+WebDragSource::WebDragSource(gfx::NativeWindow source_wnd, WebView* view)
+    : ui::DragSource(),
+      source_wnd_(source_wnd),
+      view_(view),
+      effect_(DROPEFFECT_NONE) {
+}
+
+WebDragSource::~WebDragSource() {
+}
+
+void WebDragSource::OnDragSourceCancel() {
+  // Delegate to the UI thread if we do drag-and-drop in the background thread.
+  if (!CefThread::CurrentlyOn(CefThread::UI)) {
+    CefThread::PostTask(
+        CefThread::UI, FROM_HERE,
+        NewRunnableMethod(this, &WebDragSource::OnDragSourceCancel));
+    return;
+  }
+
+  if (!view_)
+    return;
+
+  gfx::Point client;
+  gfx::Point screen;
+  GetCursorPositions(source_wnd_, &client, &screen);
+  view_->dragSourceEndedAt(client, screen, WebDragOperationNone);
+}
+
+void WebDragSource::OnDragSourceDrop() {
+  // On Windows, we check for drag end in IDropSource::QueryContinueDrag which
+  // happens before IDropTarget::Drop is called. HTML5 requires the "dragend"
+  // event to happen after the "drop" event. Since Windows calls these two
+  // directly after each other we can just post a task to handle the
+  // OnDragSourceDrop after the current task.
+  CefThread::PostTask(
+      CefThread::UI, FROM_HERE,
+      NewRunnableMethod(this, &WebDragSource::DelayedOnDragSourceDrop));
+}
+
+void WebDragSource::DelayedOnDragSourceDrop() {
+  if (!view_)
+    return;
+
+  gfx::Point client;
+  gfx::Point screen;
+  GetCursorPositions(source_wnd_, &client, &screen);
+  view_->dragSourceEndedAt(client, screen,
+      web_drag_utils_win::WinDragOpToWebDragOp(effect_));
+}
+
+void WebDragSource::OnDragSourceMove() {
+  // Delegate to the UI thread if we do drag-and-drop in the background thread.
+  if (!CefThread::CurrentlyOn(CefThread::UI)) {
+    CefThread::PostTask(
+        CefThread::UI, FROM_HERE,
+        NewRunnableMethod(this, &WebDragSource::OnDragSourceMove));
+    return;
+  }
+
+  if (!view_)
+    return;
+
+  gfx::Point client;
+  gfx::Point screen;
+  GetCursorPositions(source_wnd_, &client, &screen);
+  view_->dragSourceMovedTo(client, screen, WebDragOperationNone);
+}