1// Copyright (c) 2011 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "chrome/browser/tab_contents/web_drag_source_win.h"
6
7#include "base/task.h"
8#include "chrome/browser/tab_contents/web_drag_utils_win.h"
9#include "content/browser/browser_thread.h"
10#include "content/browser/renderer_host/render_view_host.h"
11#include "content/browser/tab_contents/tab_contents.h"
12#include "content/common/notification_source.h"
13#include "content/common/notification_type.h"
14
15using WebKit::WebDragOperationNone;
16
17namespace {
18
19static void GetCursorPositions(gfx::NativeWindow wnd, gfx::Point* client,
20                               gfx::Point* screen) {
21  POINT cursor_pos;
22  GetCursorPos(&cursor_pos);
23  screen->SetPoint(cursor_pos.x, cursor_pos.y);
24  ScreenToClient(wnd, &cursor_pos);
25  client->SetPoint(cursor_pos.x, cursor_pos.y);
26}
27
28}  // namespace
29
30///////////////////////////////////////////////////////////////////////////////
31// WebDragSource, public:
32
33WebDragSource::WebDragSource(gfx::NativeWindow source_wnd,
34                             TabContents* tab_contents)
35    : ui::DragSource(),
36      source_wnd_(source_wnd),
37      render_view_host_(tab_contents->render_view_host()),
38      effect_(DROPEFFECT_NONE) {
39  registrar_.Add(this, NotificationType::TAB_CONTENTS_SWAPPED,
40                 Source<TabContents>(tab_contents));
41  registrar_.Add(this, NotificationType::TAB_CONTENTS_DISCONNECTED,
42                 Source<TabContents>(tab_contents));
43}
44
45WebDragSource::~WebDragSource() {
46}
47
48void WebDragSource::OnDragSourceCancel() {
49  // Delegate to the UI thread if we do drag-and-drop in the background thread.
50  if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
51    BrowserThread::PostTask(
52        BrowserThread::UI, FROM_HERE,
53        NewRunnableMethod(this, &WebDragSource::OnDragSourceCancel));
54    return;
55  }
56
57  if (!render_view_host_)
58    return;
59
60  gfx::Point client;
61  gfx::Point screen;
62  GetCursorPositions(source_wnd_, &client, &screen);
63  render_view_host_->DragSourceEndedAt(client.x(), client.y(),
64                                       screen.x(), screen.y(),
65                                       WebDragOperationNone);
66}
67
68void WebDragSource::OnDragSourceDrop() {
69  // On Windows, we check for drag end in IDropSource::QueryContinueDrag which
70  // happens before IDropTarget::Drop is called. HTML5 requires the "dragend"
71  // event to happen after the "drop" event. Since  Windows calls these two
72  // directly after each other we can just post a task to handle the
73  // OnDragSourceDrop after the current task.
74  BrowserThread::PostTask(
75      BrowserThread::UI, FROM_HERE,
76      NewRunnableMethod(this, &WebDragSource::DelayedOnDragSourceDrop));
77}
78
79void WebDragSource::DelayedOnDragSourceDrop() {
80  if (!render_view_host_)
81    return;
82
83  gfx::Point client;
84  gfx::Point screen;
85  GetCursorPositions(source_wnd_, &client, &screen);
86  render_view_host_->DragSourceEndedAt(
87      client.x(), client.y(), screen.x(), screen.y(),
88      web_drag_utils_win::WinDragOpToWebDragOp(effect_));
89}
90
91void WebDragSource::OnDragSourceMove() {
92  // Delegate to the UI thread if we do drag-and-drop in the background thread.
93  if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
94    BrowserThread::PostTask(
95        BrowserThread::UI, FROM_HERE,
96        NewRunnableMethod(this, &WebDragSource::OnDragSourceMove));
97    return;
98  }
99
100  if (!render_view_host_)
101    return;
102
103  gfx::Point client;
104  gfx::Point screen;
105  GetCursorPositions(source_wnd_, &client, &screen);
106  render_view_host_->DragSourceMovedTo(client.x(), client.y(),
107                                       screen.x(), screen.y());
108}
109
110void WebDragSource::Observe(NotificationType type,
111    const NotificationSource& source, const NotificationDetails& details) {
112  if (NotificationType::TAB_CONTENTS_SWAPPED == type) {
113    // When the tab contents get swapped, our render view host goes away.
114    // That's OK, we can continue the drag, we just can't send messages back to
115    // our drag source.
116    render_view_host_ = NULL;
117  } else if (NotificationType::TAB_CONTENTS_DISCONNECTED == type) {
118    // This could be possible when we close the tab and the source is still
119    // being used in DoDragDrop at the time that the virtual file is being
120    // downloaded.
121    render_view_host_ = NULL;
122  }
123}
124