Support dragging a virtual file out of the browser.

chrome/browser/views/tab_contents/tab_contents_drag_win.cc

+// Copyright (c) 2009 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 "chrome/browser/views/tab_contents/tab_contents_drag_win.h"
+
+#include <windows.h>
+
+#include "base/file_path.h"
+#include "base/message_loop.h"
+#include "base/task.h"
+#include "base/thread.h"
+#include "base/win_util.h"
+#include "chrome/browser/bookmarks/bookmark_drag_data.h"
+#include "chrome/browser/chrome_thread.h"
+#include "chrome/browser/download/drag_download_file_win.h"
+#include "chrome/browser/profile.h"
+#include "chrome/browser/tab_contents/tab_contents.h"
+#include "chrome/browser/tab_contents/web_drag_source_win.h"
+#include "chrome/browser/tab_contents/web_drop_target_win.h"
+#include "chrome/browser/views/tab_contents/tab_contents_view_win.h"
+#include "chrome/common/url_constants.h"
+#include "net/base/net_util.h"
+#include "webkit/glue/webdropdata.h"
+
+using WebKit::WebDragOperationsMask;
+
+namespace {
+
+HHOOK msg_hook = NULL;
+DWORD drag_out_thread_id = 0;
+bool mouse_up_received = false;
+
+LRESULT CALLBACK MsgFilterProc(int code, WPARAM wparam, LPARAM lparam) {
+  if (code == base::MessagePumpForUI::kMessageFilterCode &&
+      !mouse_up_received) {
+    MSG* msg = reinterpret_cast<MSG*>(lparam);
+    // We do not care about WM_SYSKEYDOWN and WM_SYSKEYUP because when ALT key
+    // is pressed down on drag-and-drop, it means to create a link.
+    if (msg->message == WM_MOUSEMOVE || msg->message == WM_LBUTTONUP ||
+        msg->message == WM_KEYDOWN || msg->message == WM_KEYUP) {
+      // Forward the message from the UI thread to the drag-and-drop thread.
+      PostThreadMessage(drag_out_thread_id,
+                        msg->message,
+                        msg->wParam,
+                        msg->lParam);
+
+      // If the left button is up, we do not need to forward the message any
+      // more.
+      if (msg->message == WM_LBUTTONUP || !(GetKeyState(VK_LBUTTON) & 0x8000))
+        mouse_up_received = true;
+
+      return TRUE;
+    }
+  }
+  return CallNextHookEx(msg_hook, code, wparam, lparam);
+}
+
+}  // namespace
+
+class DragDropThread : public base::Thread {
+ public:
+  explicit DragDropThread(TabContentsDragWin* drag_handler)
+       : base::Thread("Chrome_DragDropThread"),
+         drag_handler_(drag_handler) {
+  }
+
+  virtual ~DragDropThread() {
+    Thread::Stop();
+  }
+
+ protected:
+  // base::Thread implementations:
+  virtual void Init() {
+    int ole_result = OleInitialize(NULL);
+    DCHECK(ole_result == S_OK);
+  }
+
+  virtual void CleanUp() {
+    OleUninitialize();
+  }
+
+ private:
+  // Hold a reference count to TabContentsDragWin to make sure that it is always
+  // alive in the thread lifetime.
+  scoped_refptr<TabContentsDragWin> drag_handler_;
+
+  DISALLOW_COPY_AND_ASSIGN(DragDropThread);
+};
+
+TabContentsDragWin::TabContentsDragWin(TabContentsViewWin* view)
+    : view_(view),
+      drag_ended_(false),
+      old_drop_target_suspended_state_(false) {
+#ifndef NDEBUG
+  drag_drop_thread_id_ = 0;
+#endif
+}
+
+TabContentsDragWin::~TabContentsDragWin() {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
+  DCHECK(!drag_source_.get());
+  DCHECK(!drag_drop_thread_.get());
+}
+
+void TabContentsDragWin::StartDragging(const WebDropData& drop_data,
+                                       WebDragOperationsMask ops) {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
+
+  drag_source_ = new WebDragSource(view_->GetNativeView(),
+                                   view_->tab_contents());
+
+  const GURL& page_url = view_->tab_contents()->GetURL();
+  const std::string& page_encoding = view_->tab_contents()->encoding();
+
+  // If it is not drag-out, do the drag-and-drop in the current UI thread.
+  if (!drop_data.download_url.is_valid()) {
+    DoDragging(drop_data, ops, page_url, page_encoding);
+    EndDragging(false);
+    return;
+  }
+
+  // We do not want to drag and drop the download to itself.
+  old_drop_target_suspended_state_ = view_->drop_target()->suspended();
+  view_->drop_target()->set_suspended(true);
+
+  // Start a background thread to do the drag-and-drop.
+  DCHECK(!drag_drop_thread_.get());
+  drag_drop_thread_.reset(new DragDropThread(this));
+  base::Thread::Options options;
+  options.message_loop_type = MessageLoop::TYPE_UI;
+  if (drag_drop_thread_->StartWithOptions(options)) {
+    drag_drop_thread_->message_loop()->PostTask(
+        FROM_HERE,
+        NewRunnableMethod(this,
+                          &TabContentsDragWin::StartBackgroundDragging,
+                          drop_data,
+                          ops,
+                          page_url,
+                          page_encoding));
+  }
+
+  // Install a hook procedure to monitor the messages so that we can forward
+  // the appropriate ones to the background thread.
+  drag_out_thread_id = drag_drop_thread_->thread_id();
+  mouse_up_received = false;
+  DCHECK(!msg_hook);
+  msg_hook = SetWindowsHookEx(WH_MSGFILTER,
+                              MsgFilterProc,
+                              NULL,
+                              GetCurrentThreadId());
+
+  // Attach the input state of the background thread to the UI thread so that
+  // SetCursor can work from the background thread.
+  AttachThreadInput(drag_out_thread_id, GetCurrentThreadId(), TRUE);
+}
+
+void TabContentsDragWin::StartBackgroundDragging(
+    const WebDropData& drop_data,
+    WebDragOperationsMask ops,
+    const GURL& page_url,
+    const std::string& page_encoding) {
+#ifndef NDEBUG
+  drag_drop_thread_id_ = PlatformThread::CurrentId();
+#endif
+
+  DoDragging(drop_data, ops, page_url, page_encoding);
+  ChromeThread::PostTask(
+      ChromeThread::UI, FROM_HERE,
+      NewRunnableMethod(this, &TabContentsDragWin::EndDragging, true));
+}
+
+void TabContentsDragWin::PrepareDragForDownload(
+    const WebDropData& drop_data,
+    OSExchangeData* data,
+    const GURL& page_url,
+    const std::string& page_encoding) {
+  // Provide the data as file (CF_HDROP). A temporary download file with the
+  // Zone.Identifier ADS (Alternate Data Stream) attached will be created.
+  scoped_refptr<DragDownloadFile> download_file =
+      new DragDownloadFile(drop_data.download_url,
+                           page_url,
+                           page_encoding,
+                           view_->tab_contents());
+  OSExchangeData::DownloadFileInfo* file_download =
+      new OSExchangeData::DownloadFileInfo(FilePath(),
+                                           0,
+                                           download_file.get());
+  data->SetDownloadFileInfo(file_download);
+
+  // Enable asynchronous operation.
+  OSExchangeDataProviderWin::GetIAsyncOperation(*data)->SetAsyncMode(TRUE);
+}
+
+void TabContentsDragWin::PrepareDragForFileContents(
+    const WebDropData& drop_data, OSExchangeData* data) {
+  // Images without ALT text will only have a file extension so we need to
+  // synthesize one from the provided extension and URL.
+  FilePath file_name(drop_data.file_description_filename);
+  file_name = file_name.BaseName().RemoveExtension();
+  if (file_name.value().empty()) {
+    // Retrieve the name from the URL.
+    file_name = net::GetSuggestedFilename(drop_data.url, "", "", FilePath());
+    if (file_name.value().size() + drop_data.file_extension.size() + 1 >
+        MAX_PATH) {
+      file_name = FilePath(file_name.value().substr(
+          0, MAX_PATH - drop_data.file_extension.size() - 2));
+    }
+  }
+  file_name = file_name.ReplaceExtension(drop_data.file_extension);
+  data->SetFileContents(file_name.value(), drop_data.file_contents);
+}
+
+void TabContentsDragWin::PrepareDragForUrl(const WebDropData& drop_data,
+                                           OSExchangeData* data) {
+  if (drop_data.url.SchemeIs(chrome::kJavaScriptScheme)) {
+    // We don't want to allow javascript URLs to be dragged to the desktop,
+    // but we do want to allow them to be added to the bookmarks bar
+    // (bookmarklets). So we create a fake bookmark entry (BookmarkDragData
+    // object) which explorer.exe cannot handle, and write the entry to data.
+    BookmarkDragData::Element bm_elt;
+    bm_elt.is_url = true;
+    bm_elt.url = drop_data.url;
+    bm_elt.title = drop_data.url_title;
+
+    BookmarkDragData bm_drag_data;
+    bm_drag_data.elements.push_back(bm_elt);
+
+    // Pass in NULL as the profile so that the bookmark always adds the url
+    // rather than trying to move an existing url.
+    bm_drag_data.Write(NULL, data);
+  } else {
+    data->SetURL(drop_data.url, drop_data.url_title);
+  }
+}
+
+void TabContentsDragWin::DoDragging(const WebDropData& drop_data,
+                                    WebDragOperationsMask ops,
+                                    const GURL& page_url,
+                                    const std::string& page_encoding) {
+  OSExchangeData data;
+
+  // TODO(tc): Generate an appropriate drag image.
+
+  if (drop_data.download_url.is_valid()) {
+    PrepareDragForDownload(drop_data, &data, page_url, page_encoding);
+
+    // Set the observer.
+    OSExchangeDataProviderWin::GetDataObjectImpl(data)->set_observer(this);
+  } else {
+    // We set the file contents before the URL because the URL also sets file
+    // contents (to a .URL shortcut).  We want to prefer file content data over
+    // a shortcut so we add it first.
+    if (!drop_data.file_contents.empty())
+      PrepareDragForFileContents(drop_data, &data);
+    if (!drop_data.text_html.empty())
+      data.SetHtml(drop_data.text_html, drop_data.html_base_url);
+    if (drop_data.url.is_valid())
+      PrepareDragForUrl(drop_data, &data);
+    if (!drop_data.plain_text.empty())
+      data.SetString(drop_data.plain_text);
+  }
+
+  DWORD effects = 0;
+
+  // We need to enable recursive tasks on the message loop so we can get
+  // updates while in the system DoDragDrop loop.
+  bool old_state = MessageLoop::current()->NestableTasksAllowed();
+  MessageLoop::current()->SetNestableTasksAllowed(true);
+  DoDragDrop(OSExchangeDataProviderWin::GetIDataObject(data), drag_source_,
+             DROPEFFECT_COPY | DROPEFFECT_LINK, &effects);
+  // TODO(snej): Use 'ops' param instead of hardcoding dropeffects
+  MessageLoop::current()->SetNestableTasksAllowed(old_state);
+}
+
+void TabContentsDragWin::EndDragging(bool restore_suspended_state) {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
+
+  if (drag_ended_)
+    return;
+  drag_ended_ = true;
+
+  if (restore_suspended_state)
+    view_->drop_target()->set_suspended(old_drop_target_suspended_state_);
+
+  drag_source_ = NULL;
+
+  if (msg_hook) {
+    AttachThreadInput(drag_out_thread_id, GetCurrentThreadId(), FALSE);
+    UnhookWindowsHookEx(msg_hook);
+    msg_hook = NULL;
+  }
+
+  view_->EndDragging();
+}
+
+void TabContentsDragWin::CancelDrag() {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
+
+  drag_source_->CancelDrag();
+}
+
+void TabContentsDragWin::CloseThread() {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
+
+  drag_drop_thread_.reset();
+}
+
+void TabContentsDragWin::OnWaitForData() {
+  DCHECK(drag_drop_thread_id_ == PlatformThread::CurrentId());
+
+  // When the left button is release and we start to wait for the data, end
+  // the dragging before DoDragDrop returns. This makes the page leave the drag
+  // mode so that it can start to process the normal input events.
+  ChromeThread::PostTask(
+      ChromeThread::UI, FROM_HERE,
+      NewRunnableMethod(this, &TabContentsDragWin::EndDragging, true));
+}
+
+void TabContentsDragWin::OnDataObjectDisposed() {
+  DCHECK(drag_drop_thread_id_ == PlatformThread::CurrentId());
+
+  // The drag-and-drop thread is only closed after OLE is done with
+  // DataObjectImpl.
+  ChromeThread::PostTask(
+      ChromeThread::UI, FROM_HERE,
+      NewRunnableMethod(this, &TabContentsDragWin::CloseThread));
+}