Add installer::SetupSingleton.

chrome/installer/setup/setup_singleton.cc

Index: chrome/installer/setup/setup_singleton.cc
diff --git a/chrome/installer/setup/setup_singleton.cc b/chrome/installer/setup/setup_singleton.cc
new file mode 100644
index 0000000000000000000000000000000000000000..de73e9f60c1f258f0e21f60cce659e25a028685e
--- /dev/null
+++ b/chrome/installer/setup/setup_singleton.cc
@@ -0,0 +1,138 @@
+// 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/installer/setup/setup_singleton.h"
+
+#include "base/files/file_path.h"
+#include "base/logging.h"
+#include "base/metrics/histogram_macros.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/time/time.h"
+#include "chrome/installer/util/installation_state.h"
+#include "chrome/installer/util/installer_state.h"
+
+namespace installer {
+
+namespace {
+
+enum SetupSingletonAcquisitionResult {
+  // The setup singleton was acquired successfully.
+  SETUP_SINGLETON_ACQUISITION_SUCCESS = 0,
+  // Acquisition of the exit event mutex timed out.
+  SETUP_SINGLETON_ACQUISITION_EXIT_EVENT_MUTEX_TIMEOUT = 1,
+  // Acquisition of the setup mutex timed out.
+  SETUP_SINGLETON_ACQUISITION_SETUP_MUTEX_TIMEOUT = 2,
+  SETUP_SINGLETON_ACQUISITION_RESULT_COUNT,
+};
+
+void RecordSetupSingletonAcquisitionResultHistogram(
+    SetupSingletonAcquisitionResult result) {
+  UMA_HISTOGRAM_ENUMERATION("Setup.Install.SingletonAcquisitionResult", result,
+                            SETUP_SINGLETON_ACQUISITION_RESULT_COUNT);
+}
+
+}  // namespace
+
+std::unique_ptr<SetupSingleton> SetupSingleton::Acquire(
+    const base::CommandLine& command_line,
+    const MasterPreferences& master_preferences,
+    InstallationState* original_state,
+    InstallerState* installer_state) {
+  DCHECK(original_state);
+  DCHECK(installer_state);
+
+  const base::string16 sync_primitive_name_suffix(
+      base::SizeTToString16(std::hash<base::FilePath::StringType>()(
+          installer_state->target_path().value())));
+
+  std::unique_ptr<SetupSingleton> setup_singleton(
+      new SetupSingleton(sync_primitive_name_suffix));
+
+  {
+    // Acquire a mutex to ensure that a single call to SetupSingleton::Acquire()
+    // signals |exit_event_| and waits for |setup_mutex_| to be released at a
+    // time.
+    base::win::ScopedHandle exit_event_mutex(::CreateMutex(
+        nullptr, FALSE,
+        (L"Global\\ChromeSetupExitEventMutex_" + sync_primitive_name_suffix)
+            .c_str()));
+    DCHECK(exit_event_mutex.IsValid());
+    ScopedHoldMutex scoped_hold_exit_event_mutex;
+    if (!scoped_hold_exit_event_mutex.Acquire(exit_event_mutex.Get())) {
+      RecordSetupSingletonAcquisitionResultHistogram(
+          SETUP_SINGLETON_ACQUISITION_EXIT_EVENT_MUTEX_TIMEOUT);
+      return nullptr;
+    }
+
+    // Signal |exit_event_|. This causes any call to WaitForInterrupt() on a
+    // SetupSingleton bound to the same Chrome installation to return
+    // immediately.
+    setup_singleton->exit_event_.Signal();
+
+    // Acquire |setup_mutex_|.
+    if (!setup_singleton->scoped_hold_setup_mutex_.Acquire(
+            setup_singleton->setup_mutex_.Get())) {
+      RecordSetupSingletonAcquisitionResultHistogram(
+          SETUP_SINGLETON_ACQUISITION_SETUP_MUTEX_TIMEOUT);
+      return nullptr;
+    }
+    setup_singleton->exit_event_.Reset();
+  }
+
+  // Update |original_state| and |installer_state|.
+  original_state->Initialize();
+  installer_state->Initialize(command_line, master_preferences,
+                              *original_state);
+
+  RecordSetupSingletonAcquisitionResultHistogram(
+      SETUP_SINGLETON_ACQUISITION_SUCCESS);
+  return setup_singleton;
+}
+
+SetupSingleton::~SetupSingleton() = default;
+
+bool SetupSingleton::WaitForInterrupt(const base::TimeDelta& max_time) {
+  const bool exit_event_signaled = exit_event_.TimedWait(max_time);
+  return exit_event_signaled;
+}
+
+SetupSingleton::ScopedHoldMutex::ScopedHoldMutex() = default;
+
+SetupSingleton::ScopedHoldMutex::~ScopedHoldMutex() {
+  if (mutex_ != INVALID_HANDLE_VALUE)
+    ::ReleaseMutex(mutex_);
+}
+
+bool SetupSingleton::ScopedHoldMutex::Acquire(HANDLE mutex) {
+  DCHECK_NE(INVALID_HANDLE_VALUE, mutex);
+  DCHECK_EQ(INVALID_HANDLE_VALUE, mutex_);
+
+  const DWORD wait_return_value = ::WaitForSingleObject(
+      mutex,
+      static_cast<DWORD>(base::TimeDelta::FromSeconds(5).InMilliseconds()));
+  if (wait_return_value == WAIT_ABANDONED ||
+      wait_return_value == WAIT_OBJECT_0) {
+    mutex_ = mutex;
+    return true;
+  }
+
+  DPCHECK(wait_return_value != WAIT_FAILED);
+  return false;
+}
+
+SetupSingleton::SetupSingleton(const base::string16& sync_primitive_name_suffix)
+    : setup_mutex_(::CreateMutex(
+          nullptr,
+          FALSE,
+          (L"Global\\ChromeSetupMutex_" + sync_primitive_name_suffix).c_str())),
+      exit_event_(base::win::ScopedHandle(::CreateEvent(
+          nullptr,
+          TRUE,
+          FALSE,
+          (L"Global\\ChromeSetupExitEvent_" + sync_primitive_name_suffix)
+              .c_str()))) {
+  DCHECK(setup_mutex_.IsValid());
+}
+
+}  // namespace installer