Icon Capture Utility For Linux, Windows and Mac

chrome/browser/media/window_icon_util_x11.cc

+// 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.
+
+#include "chrome/browser/media/window_icon_util.h"
+
+#include <X11/Xatom.h>
+#include <X11/Xutil.h>
+
+#include "ui/gfx/x/x11_types.h"
+
+gfx::ImageSkia WindowIconUtil::GetWindowIcon(content::DesktopMediaID id) {
+  Display* display = gfx::GetXDisplay();
+  Atom property = XInternAtom(display, "_NET_WM_ICON", True);
+  Atom actual_type;
+  int actual_format;
+  unsigned long bytes_after;  // NOLINT: type required by XGetWindowProperty
+  unsigned long size;
+  long* data;
+
+  int status = XGetWindowProperty(display, id.id, property, 0L,
+                                  ~0L, False, AnyPropertyType, &actual_type,
+                                  &actual_format, &size, &bytes_after,
+                                  reinterpret_cast<unsigned char**>(&data));
+  if (status != Success) {
+    return gfx::ImageSkia();
+  }
+
+  int width = 0;
+  int height = 0;
+  int start = 0;
+  int i = 0;
+  while (i < static_cast<int>(size)) {

[Sergey Ulanov, 2016/08/18 05:38:19]

Please add a comment above to explain what happens here, particularly format of
the data returned.

[qiangchen, 2016/08/18 20:07:46]

Done.

+    if (i == 0 || static_cast<int>(data[i] * data[i + 1]) > width * height) {

[Sergey Ulanov, 2016/08/18 05:38:18]

data[i+1] may be outside of the buffer size. Need to verify that i + 1 < size
before using data[i+1].

[qiangchen, 2016/08/18 20:07:46]

Done.

+      width = static_cast<int>(data[i]);
+      height = static_cast<int>(data[i + 1]);
+      start = i + 2;

[Sergey Ulanov, 2016/08/18 05:38:19]

verify here that start + 2 + width*height < size

[qiangchen, 2016/08/18 20:07:46]

Done.

+    }
+    i = i + 2 + static_cast<int>(data[i] * data[i + 1]);
+  }
+
+  SkBitmap result;
+  result.allocN32Pixels(width, height, false);
+  result.lockPixels();
+
+  uint32_t* pixels_data = reinterpret_cast<uint32_t*>(result.getPixels());
+
+  for (long y = 0; y < height; ++y) {
+    for (long x = 0; x < width; ++x) {
+      pixels_data[result.rowBytesAsPixels() * y + x] = SkPreMultiplyColor(

[Sergey Ulanov, 2016/08/18 05:38:19]

nit: you can allocate SkBitmap of type kUnpremul_SkAlphaType, then you wouldn't
need to premultiply each pixel. and this can be simple memcpy().

[qiangchen, 2016/08/18 20:07:46]

Create SkBitmap with Unpremul_SkAlphaType.

But memcpy cannot work, because we are converting long to uint32

+          static_cast<uint32_t>(data[start + width * y + x]));
+    }
+  }
+
+  XFree(data);
+  return gfx::ImageSkia::CreateFrom1xBitmap(result);
+}