linux_aura: Implement dropping in chrome.

ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc

+// Copyright (c) 2012 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 "ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.h"
+
+#include <X11/Xatom.h>
+
+#include "base/event_types.h"
+#include "base/message_loop.h"
+#include "ui/aura/client/drag_drop_client.h"
+#include "ui/aura/client/drag_drop_delegate.h"
+#include "ui/aura/root_window.h"
+#include "ui/aura/window.h"
+#include "ui/base/dragdrop/drag_drop_types.h"
+#include "ui/base/dragdrop/os_exchange_data.h"
+#include "ui/base/dragdrop/os_exchange_data_provider_aurax11.h"
+#include "ui/base/events/event.h"
+#include "ui/base/x/x11_util.h"
+#include "ui/views/widget/desktop_aura/desktop_root_window_host_x11.h"
+
+using aura::client::DragDropDelegate;
+using ui::OSExchangeData;
+
+namespace {
+
+const char* kAtomsToCache[] = {
+  "XdndActionAsk",
+  "XdndActionCopy",
+  "XdndActionLink",
+  "XdndActionList",
+  "XdndActionMove",
+  "XdndActionPrivate",
+  "XdndAware",
+  "XdndDrop",
+  "XdndEnter",
+  "XdndFinished",
+  "XdndLeave",
+  "XdndPosition",
+  "XdndProxy",  // Proxy windows?
+  "XdndSelection",
+  "XdndStatus",
+  "XdndTypeList",
+  NULL
+};
+
+}  // namespace
+
+namespace views {
+
+class DesktopDragDropClientAuraX11::X11DragContext
+    : public MessageLoop::Dispatcher {
+ public:
+  X11DragContext(ui::X11AtomCache* atom_cache,
+                 const XClientMessageEvent& event);
+  ~X11DragContext();
+
+  const std::vector<Atom>& targets() { return targets_; }
+
+  // Reads the "XdndActionList" property from |source_window| and copies it
+  // into |actions|.
+  void ReadActions();
+
+  // Creates a ui::DragDropTypes::DragOperation representation of the current
+  // action list.
+  int GetDragOperation() const;
+
+ private:
+  // Overridden from MessageLoop::Dispatcher:
+  virtual bool Dispatch(const base::NativeEvent& event) OVERRIDE;
+
+  // The atom cache owned by our parent.
+  ui::X11AtomCache* atom_cache_;
+
+  // The XID of the window that's initiated the drag.
+  unsigned long source_window_;
+
+  // targets.
+  std::vector<Atom> targets_;
+
+  // supplied actions
+  std::vector<Atom> actions_;
+};
+
+DesktopDragDropClientAuraX11::X11DragContext::X11DragContext(
+    ui::X11AtomCache* atom_cache,
+    const XClientMessageEvent& event)
+    : atom_cache_(atom_cache),
+      source_window_(event.data.l[0]) {
+  bool get_types = ((event.data.l[1] & 1) != 0);
+
+  if (get_types) {
+    if (!ui::GetAtomArrayProperty(source_window_,
+                                  "XdndTypeList",
+                                  &targets_)) {
+      return;
+    }
+  } else {
+    // data.l[2,3,4] contain the first three types. Unused slots can be None.
+    for (int i = 0; i < 3; ++i) {
+      if (event.data.l[2+i] != None) {
+        targets_.push_back(event.data.l[2+i]);
+      }
+    }
+  }
+
+  // TODO(erg): If this window is part of our process, don't listen through the
+  // MessagePump, but instead listen to the DesktopDragDropClientAuraX11
+  // associated with that window.
+  base::MessagePumpAuraX11::Current()->AddDispatcherForWindow(
+      this, source_window_);
+  XSelectInput(base::MessagePumpAuraX11::GetDefaultXDisplay(),
+               source_window_, PropertyChangeMask);
+
+  // We must perform a full sync here because we could be racing
+  // |source_window_|.
+  XSync(base::MessagePumpAuraX11::GetDefaultXDisplay(), False);
+
+  ReadActions();
+}
+
+DesktopDragDropClientAuraX11::X11DragContext::~X11DragContext() {
+  // Unsubscribe to message events.
+  base::MessagePumpAuraX11::Current()->RemoveDispatcherForWindow(
+      source_window_);
+}
+
+void DesktopDragDropClientAuraX11::X11DragContext::ReadActions() {
+  std::vector<Atom> atom_array;
+
+  // TODO(erg): The GTK+ code has a fast path that short circuits talking over
+  // X11 for local windows. When we become a drop source, we should have a
+  // similar fast path.
+
+  if (!ui::GetAtomArrayProperty(source_window_,
+                                "XdndActionList",
+                                &atom_array)) {
+    actions_.clear();
+  } else {
+    actions_.swap(atom_array);
+  }
+}
+
+int DesktopDragDropClientAuraX11::X11DragContext::GetDragOperation() const {
+  int drag_operation = ui::DragDropTypes::DRAG_NONE;
+  for (std::vector<Atom>::const_iterator it = actions_.begin();
+       it != actions_.end(); ++it) {
+    if (*it == atom_cache_->GetAtom("XdndActionCopy"))
+      drag_operation |= ui::DragDropTypes::DRAG_COPY;
+    else if (*it == atom_cache_->GetAtom("XdndActionMove"))
+      drag_operation |= ui::DragDropTypes::DRAG_MOVE;
+    else if (*it == atom_cache_->GetAtom("XdndActionLink"))
+      drag_operation |= ui::DragDropTypes::DRAG_LINK;
+  }
+
+  return drag_operation;
+}
+
+bool DesktopDragDropClientAuraX11::X11DragContext::Dispatch(
+    const base::NativeEvent& event) {
+  if (event->type == PropertyNotify &&
+      event->xproperty.atom == atom_cache_->GetAtom("XdndActionList")) {
+    ReadActions();
+  }
+  return true;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+DesktopDragDropClientAuraX11::DesktopDragDropClientAuraX11(
+    views::DesktopRootWindowHostX11* root_window_host,
+    aura::RootWindow* root_window,
+    Display* xdisplay,
+    ::Window xwindow)
+    : root_window_host_(root_window_host),
+      root_window_(root_window),
+      xdisplay_(xdisplay),
+      xwindow_(xwindow),
+      atom_cache_(xdisplay_, kAtomsToCache),
+      target_window_(NULL),
+      drag_drop_in_progress_(false),
+      drag_operation_(0) {
+  // Mark that we are aware of drag and drop concepts.
+  unsigned long xdnd_version = 5;
+  XChangeProperty(xdisplay_, xwindow_, atom_cache_.GetAtom("XdndAware"),
+                  XA_ATOM, 32, PropModeReplace,
+                  reinterpret_cast<unsigned char*>(&xdnd_version), 1);
+}
+
+DesktopDragDropClientAuraX11::~DesktopDragDropClientAuraX11() {
+}
+
+void DesktopDragDropClientAuraX11::OnXdndEnter(
+    const XClientMessageEvent& event) {
+  DVLOG(1) << "XdndEnter";
+
+  int version = (event.data.l[1] & 0xff000000) >> 24;
+  if (version < 3) {
+    LOG(ERROR) << "Received old XdndEnter message.";
+    return;
+  }
+
+  // Make sure that we've run ~X11DragContext() before creating another one.
+  current_context_.reset();
+  current_context_.reset(new X11DragContext(&atom_cache_, event));
+
+  // In the Windows implementation, we immediately call DesktopDropTargetWin::
+  // Translate(). Here, we wait until we receive an XdndPosition message
+  // because the enter message doesn't convey any positioning
+  // information.
+}
+
+void DesktopDragDropClientAuraX11::OnXdndLeave(
+    const XClientMessageEvent& event) {
+  NotifyDragLeave();
+  current_context_.reset();
+}
+
+void DesktopDragDropClientAuraX11::OnXdndPosition(
+    const XClientMessageEvent& event) {
+  DVLOG(1) << "XdndPosition";
+
+  unsigned long source_window = event.data.l[0];
+  int x_root_window = event.data.l[2] >> 16;
+  int y_root_window = event.data.l[2] & 0xffff;
+
+  if (!current_context_.get()) {
+    NOTREACHED();
+    return;
+  }
+
+  int drag_operation = ui::DragDropTypes::DRAG_NONE;
+  scoped_ptr<ui::OSExchangeData> data;
+  scoped_ptr<ui::DropTargetEvent> drop_target_event;
+  DragDropDelegate* delegate;
+  DragTranslate(gfx::Point(x_root_window, y_root_window),
+                &data, &drop_target_event, &delegate);
+  if (delegate)
+    drag_operation = delegate->OnDragUpdated(*drop_target_event);
+
+  // Sends an XdndStatus message back to the source_window. l[2,3]
+  // theoretically represent an area in the window where the current action is
+  // the same as what we're returning, but I can't find any implementation that
+  // actually making use of this. A client can return (0, 0) and/or set the
+  // first bit of l[1] to disable the feature, and it appears that gtk neither
+  // sets this nor respects it if set.
+  XEvent xev;
+  xev.xclient.type = ClientMessage;
+  xev.xclient.message_type = atom_cache_.GetAtom("XdndStatus");
+  xev.xclient.format = 32;
+  xev.xclient.window = source_window;
+  xev.xclient.data.l[0] = xwindow_;
+  xev.xclient.data.l[1] = (drag_operation != 0) ? (2 | 1) : 0;
+  xev.xclient.data.l[2] = 0;
+  xev.xclient.data.l[3] = 0;
+  xev.xclient.data.l[4] = DragOperationToAtom(drag_operation);
+
+  SendXClientEvent(source_window, &xev);
+}
+
+void DesktopDragDropClientAuraX11::OnXdndStatus(
+    const XClientMessageEvent& event) {
+  DVLOG(1) << "XdndStatus";
+}
+
+void DesktopDragDropClientAuraX11::OnXdndFinished(
+    const XClientMessageEvent& event) {
+  DVLOG(1) << "XdndFinished";
+}
+
+void DesktopDragDropClientAuraX11::OnXdndDrop(
+    const XClientMessageEvent& event) {
+  DVLOG(1) << "XdndDrop";
+
+  unsigned long source_window = event.data.l[0];
+
+  int drag_operation = ui::DragDropTypes::DRAG_NONE;
+  if (target_window_) {
+    aura::client::DragDropDelegate* delegate =
+        aura::client::GetDragDropDelegate(target_window_);
+    if (delegate) {
+      ui::OSExchangeData data(new ui::OSExchangeDataProviderAuraX11(
+          root_window_host_, xwindow_, current_context_->targets()));
+      ui::DropTargetEvent event(data,
+                                target_window_location_,
+                                target_window_root_location_,
+                                current_context_->GetDragOperation());
+      drag_operation = delegate->OnPerformDrop(event);
+    }
+
+    target_window_->RemoveObserver(this);
+    target_window_ = NULL;
+  }
+
+  XEvent xev;
+  xev.xclient.type = ClientMessage;
+  xev.xclient.message_type = atom_cache_.GetAtom("XdndFinished");
+  xev.xclient.format = 32;
+  xev.xclient.window = source_window;
+  xev.xclient.data.l[0] = xwindow_;
+  xev.xclient.data.l[1] = (drag_operation != 0) ? 1 : 0;
+  xev.xclient.data.l[2] = DragOperationToAtom(drag_operation);
+
+  SendXClientEvent(source_window, &xev);
+}
+
+int DesktopDragDropClientAuraX11::StartDragAndDrop(
+    const ui::OSExchangeData& data,
+    aura::RootWindow* root_window,
+    aura::Window* source_window,
+    const gfx::Point& root_location,
+    int operation,
+    ui::DragDropTypes::DragEventSource source) {
+  NOTIMPLEMENTED();
+
+  // TODO(erg): Once this is implemented, make sure to reenable the
+  // NativeTextfieldViewsTest_DragAndDrop* tests.
+
+  return ui::DragDropTypes::DRAG_NONE;
+}
+
+void DesktopDragDropClientAuraX11::DragUpdate(aura::Window* target,
+                                              const ui::LocatedEvent& event) {
+  NOTIMPLEMENTED();
+}
+
+void DesktopDragDropClientAuraX11::Drop(aura::Window* target,
+                                        const ui::LocatedEvent& event) {
+  NOTIMPLEMENTED();
+}
+
+void DesktopDragDropClientAuraX11::DragCancel() {
+  NOTIMPLEMENTED();
+}
+
+bool DesktopDragDropClientAuraX11::IsDragDropInProgress() {
+  return drag_drop_in_progress_;
+}
+
+void DesktopDragDropClientAuraX11::OnWindowDestroyed(aura::Window* window) {
+  DCHECK(window == target_window_);
+  target_window_ = NULL;
+}
+
+void DesktopDragDropClientAuraX11::DragTranslate(
+    const gfx::Point& root_window_location,
+    scoped_ptr<ui::OSExchangeData>* data,
+    scoped_ptr<ui::DropTargetEvent>* event,
+    aura::client::DragDropDelegate** delegate) {
+  gfx::Point root_location = root_window_location;
+  root_window_->ConvertPointFromNativeScreen(&root_location);
+  aura::Window* target_window =
+      root_window_->GetEventHandlerForPoint(root_location);
+  bool target_window_changed = false;
+  if (target_window != target_window_) {
+    if (target_window_)
+      NotifyDragLeave();
+    target_window_ = target_window;
+    if (target_window_)
+      target_window_->AddObserver(this);
+    target_window_changed = true;
+  }
+  *delegate = NULL;
+  if (!target_window_)
+    return;
+  *delegate = aura::client::GetDragDropDelegate(target_window_);
+  if (!*delegate)
+    return;
+
+  data->reset(new OSExchangeData(new ui::OSExchangeDataProviderAuraX11(
+      root_window_host_, xwindow_, current_context_->targets())));
+  gfx::Point location = root_location;
+  aura::Window::ConvertPointToTarget(root_window_, target_window_, &location);
+
+  target_window_location_ = location;
+  target_window_root_location_ = root_location;
+
+  event->reset(new ui::DropTargetEvent(
+      *(data->get()),
+      location,
+      root_location,
+      current_context_->GetDragOperation()));
+  if (target_window_changed)
+    (*delegate)->OnDragEntered(*event->get());
+}
+
+void DesktopDragDropClientAuraX11::NotifyDragLeave() {
+  if (!target_window_)
+    return;
+  DragDropDelegate* delegate =
+      aura::client::GetDragDropDelegate(target_window_);
+  if (delegate)
+    delegate->OnDragExited();
+  target_window_->RemoveObserver(this);
+  target_window_ = NULL;
+}
+
+unsigned long DesktopDragDropClientAuraX11::DragOperationToAtom(
+    int drag_operation) {
+  if (drag_operation & ui::DragDropTypes::DRAG_COPY)
+    return atom_cache_.GetAtom("XdndActionCopy");
+  if (drag_operation & ui::DragDropTypes::DRAG_MOVE)
+    return atom_cache_.GetAtom("XdndActionMove");
+  if (drag_operation & ui::DragDropTypes::DRAG_LINK)
+    return atom_cache_.GetAtom("XdndActionLink");
+
+  return None;
+}
+
+void DesktopDragDropClientAuraX11::SendXClientEvent(unsigned long xid,
+                                                    XEvent* xev) {
+  DCHECK_EQ(ClientMessage, xev->type);
+
+  // TODO(erg): When I get drag receiving working, shortcut messages to the X
+  // server and call the receivers DesktopDragDropClientAuraX11 instance
+  // instead.
+  //
+  // I don't understand why the GTK+ code is doing what it's doing here. It
+  // goes out of its way to send the XEvent so that it receives a callback on
+  // success or failure, and when it fails, it then sends an internal GdkEvent
+  // about the failed drag. (And sending this message doesn't appear to go
+  // through normal xlib machinery, but instead passes through the low level
+  // xProto (the x11 wire format) that I don't understand.
+  //
+  // I'm unsure if I have to jump through those hoops, or if XSendEvent is
+  // sufficient.
+
+  XSendEvent(xdisplay_, xid, False, 0, xev);
+}
+
+}  // namespace views