From 63a8961ed1eaf86377ece40f26f8bb7c843b742d Mon Sep 17 00:00:00 2001
From: Cheng Zhao <zcbenz@gmail.com>
Date: Sun, 3 Jul 2016 14:34:35 +0900
Subject: [PATCH] views: Implement webContents.startDrag

---
 atom/browser/ui/drag_util_views.cc | 119 +++++++++++++++++++++++++++++
 1 file changed, 119 insertions(+)

diff --git a/atom/browser/ui/drag_util_views.cc b/atom/browser/ui/drag_util_views.cc
index 1db7e5439455..54bbfd1eb8ee 100644
--- a/atom/browser/ui/drag_util_views.cc
+++ b/atom/browser/ui/drag_util_views.cc
@@ -4,8 +4,127 @@
 
 #include "atom/browser/ui/drag_util.h"
 
+#if defined(OS_WIN)
+#include <objidl.h>
+#include <shlobj.h>
+#include <shobjidl.h>
+#include <stddef.h>
+#endif
+
+#include "ui/aura/window.h"
+#include "ui/base/dragdrop/drag_drop_types.h"
+#include "ui/base/dragdrop/drag_utils.h"
+#include "ui/base/dragdrop/file_info.h"
+#include "ui/base/dragdrop/os_exchange_data.h"
+#include "ui/gfx/geometry/point.h"
+#include "ui/gfx/screen.h"
+#include "ui/views/widget/widget.h"
+#include "ui/wm/public/drag_drop_client.h"
+
+#if defined(OS_WIN)
+#include "base/win/scoped_comptr.h"
+#include "base/win/scoped_hdc.h"
+#include "ui/base/dragdrop/os_exchange_data_provider_win.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/gdi_util.h"
+#include "ui/gfx/geometry/size.h"
+#include "ui/gfx/image/image_skia.h"
+#include "ui/gfx/skbitmap_operations.h"
+#endif
+
 namespace atom {
 
+namespace {
 
+#if defined(OS_WIN)
+void SetDragImageOnDataObject(HBITMAP hbitmap,
+                              const gfx::Size& size_in_pixels,
+                              const gfx::Vector2d& cursor_offset,
+                              IDataObject* data_object) {
+  base::win::ScopedComPtr<IDragSourceHelper> helper;
+  HRESULT rv = CoCreateInstance(CLSID_DragDropHelper, 0, CLSCTX_INPROC_SERVER,
+                                IID_IDragSourceHelper, helper.ReceiveVoid());
+  if (SUCCEEDED(rv)) {
+    SHDRAGIMAGE sdi;
+    sdi.sizeDragImage = size_in_pixels.ToSIZE();
+    sdi.crColorKey = 0xFFFFFFFF;
+    sdi.hbmpDragImage = hbitmap;
+    sdi.ptOffset = gfx::PointAtOffsetFromOrigin(cursor_offset).ToPOINT();
+    helper->InitializeFromBitmap(&sdi, data_object);
+  }
+}
+
+// Blit the contents of the canvas to a new HBITMAP. It is the caller's
+// responsibility to release the |bits| buffer.
+HBITMAP CreateHBITMAPFromSkBitmap(const SkBitmap& sk_bitmap) {
+  base::win::ScopedGetDC screen_dc(NULL);
+  BITMAPINFOHEADER header;
+  gfx::CreateBitmapHeader(sk_bitmap.width(), sk_bitmap.height(), &header);
+  void* bits;
+  HBITMAP bitmap =
+      CreateDIBSection(screen_dc, reinterpret_cast<BITMAPINFO*>(&header),
+                       DIB_RGB_COLORS, &bits, NULL, 0);
+  if (!bitmap || !bits)
+    return NULL;
+  DCHECK_EQ(sk_bitmap.rowBytes(), static_cast<size_t>(sk_bitmap.width() * 4));
+  SkAutoLockPixels lock(sk_bitmap);
+  memcpy(
+      bits, sk_bitmap.getPixels(), sk_bitmap.height() * sk_bitmap.rowBytes());
+  return bitmap;
+}
+
+void SetDragImageOnDataObject(const gfx::ImageSkia& image_skia,
+                              const gfx::Vector2d& cursor_offset,
+                              ui::OSExchangeData* data_object) {
+  DCHECK(data_object && !image_skia.size().IsEmpty());
+  // InitializeFromBitmap() doesn't expect an alpha channel and is confused
+  // by premultiplied colors, so unpremultiply the bitmap.
+  // SetDragImageOnDataObject(HBITMAP) takes ownership of the bitmap.
+  HBITMAP bitmap = CreateHBITMAPFromSkBitmap(
+      SkBitmapOperations::UnPreMultiply(*image_skia.bitmap()));
+  if (bitmap) {
+    // Attach 'bitmap' to the data_object.
+    SetDragImageOnDataObject(
+        bitmap,
+        gfx::Size(image_skia.bitmap()->width(), image_skia.bitmap()->height()),
+        cursor_offset,
+        ui::OSExchangeDataProviderWin::GetIDataObject(*data_object));
+  }
+}
+#endif
+
+}  // namespace
+
+void DragFileItems(const std::vector<base::FilePath>& files,
+                   const gfx::Image& icon,
+                   gfx::NativeView view) {
+  // Set up our OLE machinery
+  ui::OSExchangeData data;
+
+#if defined(OS_WIN)
+  SetDragImageOnDataObject(icon.AsImageSkia(), gfx::Vector2d(), &data);
+#endif
+  data.provider().SetDragImage(icon.AsImageSkia(), gfx::Vector2d());
+
+  std::vector<ui::FileInfo> file_infos;
+  for (const base::FilePath& file : files) {
+    file_infos.push_back(ui::FileInfo(file, base::FilePath()));
+  }
+  data.SetFilenames(file_infos);
+
+  aura::Window* root_window = view->GetRootWindow();
+  if (!root_window || !aura::client::GetDragDropClient(root_window))
+    return;
+
+  gfx::Point location = gfx::Screen::GetScreen()->GetCursorScreenPoint();
+  // TODO(varunjain): Properly determine and send DRAG_EVENT_SOURCE below.
+  aura::client::GetDragDropClient(root_window)->StartDragAndDrop(
+      data,
+      root_window,
+      view,
+      location,
+      ui::DragDropTypes::DRAG_COPY | ui::DragDropTypes::DRAG_LINK,
+      ui::DragDropTypes::DRAG_EVENT_SOURCE_MOUSE);
+}
 
 }  // namespace atom