Adds USB writing for OS X.

chrome/utility/image_writer/disk_unmounter_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/utility/image_writer/disk_unmounter_mac.h"
+
+#include <sys/socket.h>
+#include <IOKit/storage/IOStorageProtocolCharacteristics.h>
+
+#include "base/message_loop/message_loop_proxy.h"
+#include "base/message_loop/message_pump_mac.h"
+#include "base/posix/eintr_wrapper.h"
+#include "chrome/utility/image_writer/error_messages.h"
+#include "chrome/utility/image_writer/image_writer.h"
+
+namespace image_writer {
+
+DiskUnmounterMac::DiskUnmounterMac() : cf_thread_("ImageWriterDiskArb") {
+  base::Thread::Options options;
+  options.message_pump_factory = base::Bind(&CreateMessagePump);
+
+  cf_thread_.StartWithOptions(options);
+}
+
+DiskUnmounterMac::~DiskUnmounterMac() {
+  if (disk_)
+    DADiskUnclaim(disk_);
+}
+
+void DiskUnmounterMac::Unmount(const std::string& device_path,
+                               const base::Closure& success_continuation,
+                               const base::Closure& failure_continuation) {

[Robert Sesek, 2014/06/16 19:32:53]

Maybe DCHECK(!original_thread_)?

[Drew Haven, 2014/06/16 21:51:39]

I forget that we use these debug assertions to enforce constraints.  I'm used to
trying to put those in the type system, but this works.

Done.

+  original_thread_ = base::MessageLoopProxy::current();
+  success_continuation_ = success_continuation;
+  failure_continuation_ = failure_continuation;
+
+  cf_thread_.message_loop()->PostTask(
+      FROM_HERE,
+      base::Bind(&DiskUnmounterMac::UnmountOnWorker,
+                 base::Unretained(this),
+                 device_path));
+}
+
+// static
+void DiskUnmounterMac::DiskClaimed(DADiskRef disk,
+                                   DADissenterRef dissenter,
+                                   void* context) {
+  DiskUnmounterMac* disk_unmounter = static_cast<DiskUnmounterMac*>(context);
+
+  if (dissenter) {
+    LOG(ERROR) << "Unable to claim disk.";
+    disk_unmounter->Error();
+    return;
+  }
+
+  DADiskUnmount(disk,
+                kDADiskUnmountOptionForce | kDADiskUnmountOptionWhole,
+                DiskUnmounted,
+                disk_unmounter);
+}
+
+// static
+DADissenterRef DiskUnmounterMac::DiskClaimRevoked(DADiskRef disk,
+                                                  void* context) {
+  CFStringRef reason = CFSTR(
+      "Hi. Sorry to bother you, but I'm busy overwriting the entire disk "
+      "here. There's nothing to claim but the smoldering ruins of bytes "
+      "that were in flash memory. Trust me, it's nothing that you want. "
+      "All the best. Toodles!");
+  return DADissenterCreate(kCFAllocatorDefault, kDAReturnBusy, reason);
+}
+
+// static
+void DiskUnmounterMac::DiskUnmounted(DADiskRef disk,
+                                     DADissenterRef dissenter,
+                                     void* context) {
+  DiskUnmounterMac* disk_unmounter = static_cast<DiskUnmounterMac*>(context);
+
+  if (dissenter) {
+    LOG(ERROR) << "Unable to unmount disk.";
+    disk_unmounter->Error();
+    return;
+  }
+
+  disk_unmounter->original_thread_->PostTask(
+      FROM_HERE, disk_unmounter->success_continuation_);
+}
+
+void DiskUnmounterMac::UnmountOnWorker(const std::string& device_path) {
+  DCHECK(cf_thread_.message_loop() == base::MessageLoop::current());
+
+  session_.reset(DASessionCreate(NULL));
+
+  DASessionScheduleWithRunLoop(
+      session_, CFRunLoopGetCurrent(), kCFRunLoopCommonModes);
+
+  disk_.reset(DADiskCreateFromBSDName(
+      kCFAllocatorDefault, session_, device_path.c_str()));
+
+  if (!disk_) {
+    LOG(ERROR) << "Unable to get disk reference.";
+    Error();
+    return;
+  }
+
+  DADiskClaim(disk_,
+              kDADiskClaimOptionDefault,
+              DiskClaimRevoked,
+              this,
+              DiskClaimed,
+              this);
+}
+
+// static
+scoped_ptr<base::MessagePump> DiskUnmounterMac::CreateMessagePump() {

[Robert Sesek, 2014/06/16 19:32:53]

nit: implementation order should match header order

[Drew Haven, 2014/06/16 21:51:39]

Done.

+  return scoped_ptr<base::MessagePump>(new base::MessagePumpCFRunLoop);
+}
+
+void DiskUnmounterMac::Error() {
+  original_thread_->PostTask(FROM_HERE, failure_continuation_);
+}
+
+}  // namespace image_writer