Adds USB writing for OS X.

chrome/common/extensions/image_writer/image_writer_util_mac.cc

+// Copyright 2014 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/common/extensions/image_writer/image_writer_util_mac.h"
+
+#include <IOKit/storage/IOStorageProtocolCharacteristics.h>
+
+#include "base/mac/foundation_util.h"
+
+namespace extensions {
+namespace image_writer {
+
+bool IsRemovableDevice(CFDictionaryRef disk_description) {
+  CFBooleanRef internal = base::mac::GetValueFromDictionary<CFBooleanRef>(
+      disk_description, kDADiskDescriptionDeviceInternalKey);
+  CFStringRef protocol = base::mac::GetValueFromDictionary<CFStringRef>(
+      disk_description, kDADiskDescriptionDeviceProtocolKey);
+  CFStringRef io_reg_path = base::mac::GetValueFromDictionary<CFStringRef>(
+      disk_description, kDADiskDescriptionDevicePathKey);
+  CFBooleanRef ejectable = base::mac::GetValueFromDictionary<CFBooleanRef>(
+      disk_description, kDADiskDescriptionMediaEjectableKey);
+  CFBooleanRef removable = base::mac::GetValueFromDictionary<CFBooleanRef>(
+      disk_description, kDADiskDescriptionMediaRemovableKey);
+  CFBooleanRef whole = base::mac::GetValueFromDictionary<CFBooleanRef>(
+      disk_description, kDADiskDescriptionMediaWholeKey);
+  CFStringRef kind = base::mac::GetValueFromDictionary<CFStringRef>(
+      disk_description, kDADiskDescriptionMediaKindKey);
+
+  // A drive is a USB stick iff:
+  // - it is not internal
+  // - it is attached to the USB bus
+  // - it is ejectable (because it will be ejected after written to)
+  // - it is removable
+  // - it is the whole drive (although the use of
+  //   kDADiskDescriptionMatchMediaWhole should have ensured this)
+  // - it is of type IOMedia (external DVD drives and the like are IOCDMedia
+  // or
+  //   IODVDMedia)
+  bool is_usb_stick =
+      !CFBooleanGetValue(internal) &&
+      CFEqual(protocol, CFSTR(kIOPropertyPhysicalInterconnectTypeUSB)) &&

[Robert Sesek, 2014/06/10 19:47:46]

Maybe pull out line 42, 43, and 44 into its own bool, since it's common between
the two? bool is_removable_usb_device?

[Drew Haven, 2014/06/12 02:24:26]

Done.

+      CFBooleanGetValue(ejectable) && CFBooleanGetValue(removable) &&
+      CFBooleanGetValue(whole) &&
+      CFStringCompare(kind, CFSTR("IOMedia"), 0) == kCFCompareEqualTo;
+
+  // A drive is an SD card iff:
+  // - it is attached to the USB bus
+  // - it is ejectable (because it will be ejected after written to)
+  // - it is removable
+  // - it is the whole drive (although the use of
+  //   kDADiskDescriptionMatchMediaWhole should have ensured this)
+  // - it is of type IOMedia (external DVD drives and the like are IOCDMedia
+  // or
+  //   IODVDMedia)
+  // - the IORegistry device path contains "AppleUSBCardReader"
+  bool is_sd_card =
+      CFEqual(protocol, CFSTR(kIOPropertyPhysicalInterconnectTypeUSB)) &&
+      CFBooleanGetValue(ejectable) && CFBooleanGetValue(removable) &&
+      CFBooleanGetValue(whole) &&
+      CFStringCompare(kind, CFSTR("IOMedia"), 0) == kCFCompareEqualTo &&
+      CFStringFind(io_reg_path, CFSTR("AppleUSBCardReader"), 0).location !=
+          kCFNotFound;
+
+  return is_usb_stick || is_sd_card;
+}
+
+}  // image_writer
+}  // extensions