MacViews: Implemented Drag & Drop

ui/views/cocoa/drag_drop_client_mac.mm

+// Copyright 2016 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.
+
+#import "ui/views/cocoa/drag_drop_client_mac.h"
+
+#include "base/mac/mac_util.h"
+#include "base/run_loop.h"
+#include "base/strings/sys_string_conversions.h"
+#import "ui/base/dragdrop/os_exchange_data_provider_mac.h"
+#include "ui/gfx/image/image_skia_util_mac.h"
+#include "ui/views/drag_utils.h"
+#import "ui/views/cocoa/bridged_content_view.h"
+#import "ui/views/cocoa/bridged_native_widget.h"
+#include "ui/views/widget/native_widget_mac.h"
+
+@interface CocoaDragDropDataProvider ()
+- (id)initWithData:(const ui::OSExchangeData&)data;
+- (id)initWithPasteboard:(NSPasteboard*)pasteboard;
+@end
+
+@implementation CocoaDragDropDataProvider
+
+std::unique_ptr<ui::OSExchangeData> data_;
+
+- (id)initWithData:(const ui::OSExchangeData&)data {
+  if ((self = [super init])) {
+    data_.reset(new OSExchangeData(data.provider().Clone()));
+  }
+  return self;
+}
+
+- (id)initWithPasteboard:(NSPasteboard*)pasteboard {
+  if ((self = [super init])) {
+    data_ = ui::OSExchangeDataProviderMac::CreateDataFromPasteboard(pasteboard);
+  }
+  return self;
+}
+
+- (ui::OSExchangeData*)data {
+  return data_.get();
+}
+
+// NSPasteboardItemDataProvider protocol implementation.
+
+- (void)pasteboard:(NSPasteboard*)sender
+                  item:(NSPasteboardItem*)item
+    provideDataForType:(NSString*)type {
+  const ui::OSExchangeDataProviderMac& provider =
+      static_cast<const ui::OSExchangeDataProviderMac&>(data_->provider());
+  NSData* ns_data = provider.GetNSDataForType(type);
+  [sender setData:ns_data forType:type];
+}
+
+@end
+
+namespace views {
+
+DragDropClientMac::DragDropClientMac(BridgedNativeWidget* bridge,
+                                     View* root_view)
+    : drop_helper_(root_view),
+      operation_(0),
+      bridge_(bridge),
+      quit_closure_(base::Closure()) {
+  DCHECK(bridge);
+}
+
+DragDropClientMac::~DragDropClientMac() {}
+
+void DragDropClientMac::StartDragAndDrop(
+    View* view,
+    const ui::OSExchangeData& data,
+    int operation,
+    ui::DragDropTypes::DragEventSource source) {
+  data_source_.reset([[CocoaDragDropDataProvider alloc] initWithData:data]);
+  operation_ = operation;
+
+  const ui::OSExchangeDataProviderMac& provider =
+      static_cast<const ui::OSExchangeDataProviderMac&>(data.provider());
+
+  // Synthesize an event for dragging, since we can't be sure that
+  // [NSApp currentEvent] will return a valid dragging event.
+  NSWindow* window = bridge_->ns_window();
+  NSPoint position = [window mouseLocationOutsideOfEventStream];
+  NSTimeInterval event_time = [[NSApp currentEvent] timestamp];
+  NSEvent* event = [NSEvent mouseEventWithType:NSLeftMouseDragged
+                                      location:position
+                                 modifierFlags:NSLeftMouseDraggedMask
+                                     timestamp:event_time
+                                  windowNumber:[window windowNumber]
+                                       context:nil
+                                   eventNumber:0
+                                    clickCount:1
+                                      pressure:1.0];
+
+  NSImage* image = gfx::NSImageFromImageSkiaWithColorSpace(
+      provider.GetDragImage(), base::mac::GetSRGBColorSpace());
+
+  base::scoped_nsobject<NSPasteboardItem> item([[NSPasteboardItem alloc] init]);
+  [item setDataProvider:data_source_.get()
+               forTypes:ui::OSExchangeDataProviderMac::
+                            SupportedPasteboardTypes()];
+
+  base::scoped_nsobject<NSDraggingItem> drag_item(
+      [[NSDraggingItem alloc] initWithPasteboardWriter:item.get()]);
+
+  // Subtract the image's height from the y location so that the mouse will be
+  // at the upper left corner of the image.
+  NSRect dragging_frame =
+      NSMakeRect([event locationInWindow].x,
+                 [event locationInWindow].y - [image size].height,
+                 [image size].width, [image size].height);
+  [drag_item setDraggingFrame:dragging_frame contents:image];
+
+  [bridge_->ns_view() beginDraggingSessionWithItems:@[ drag_item.get() ]
+                                              event:event
+                                             source:bridge_->ns_view()];
+
+  // Since Drag and drop is asynchronous on Mac, we need to spin a nested run
+  // loop for consistency with other platforms.
+  base::RunLoop run_loop;
+  quit_closure_ = run_loop.QuitClosure();
+  run_loop.Run();
+}
+
+NSDragOperation DragDropClientMac::DragUpdate(id<NSDraggingInfo> sender) {
+  int drag_operation = ui::DragDropTypes::DRAG_NONE;
+
+  // Since dragging from non MacView sources does not generate OSExchangeData,
+  // we need to generate one based on the provided pasteboard.
+  if (!data_source_.get()) {
+    data_source_.reset([[CocoaDragDropDataProvider alloc]
+        initWithPasteboard:[sender draggingPasteboard]]);
+  }
+
+  drag_operation = drop_helper_.OnDragOver(
+      *[data_source_ data], LocationInView([sender draggingLocation]),
+      operation_);
+  return ui::DragDropTypes::DragOperationToNSDragOperation(drag_operation);
+}
+
+NSDragOperation DragDropClientMac::Drop(id<NSDraggingInfo> sender) {
+  int drag_operation = drop_helper_.OnDrop(
+      *[data_source_ data], LocationInView([sender draggingLocation]),
+      operation_);
+  return ui::DragDropTypes::DragOperationToNSDragOperation(drag_operation);
+}
+
+void DragDropClientMac::EndDrag() {
+  data_source_.reset();
+
+  // Allow a test to invoke EndDrag() without spinning the nested run loop.
+  if (!quit_closure_.is_null()) {
+    quit_closure_.Run();
+    quit_closure_.Reset();
+  }
+}
+
+gfx::Point DragDropClientMac::LocationInView(NSPoint point) const {
+  return gfx::Point(point.x, NSHeight([bridge_->ns_window() frame]) - point.y);
+}
+
+}  // namespace views