Use named events instead of lock files for service process

Use named events to signal that a service process is running.

BUG=52891
TEST=browser_tests --gtest_filter=ServiceProcess*

Review URL: http://codereview.chromium.org/3268003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@58041 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 50 insertions, 6 deletions

diff --git a/chrome/common/service_process_util.cc b/chrome/common/service_process_util.cc
index 4be6991..fe600fc 100644
--- a/chrome/common/service_process_util.cc
+++ b/chrome/common/service_process_util.cc
@@ -10,6 +10,11 @@
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/service_process_util.h"
 
+#if defined(OS_WIN)
+#include "base/scoped_handle_win.h"
+#endif
+
+// TODO(hclam): Split this file for different platforms.
 // TODO(hclam): |type| is not used at all. Different types of service process
 // should have a different instance of process and channel.
 std::string GetServiceProcessChannelName(ServiceProcessType type) {
@@ -32,24 +37,63 @@ std::string GetServiceProcessChannelName(ServiceProcessType type) {
 static FilePath GetServiceProcessLockFilePath(ServiceProcessType type) {
   FilePath user_data_dir;
   PathService::Get(chrome::DIR_USER_DATA, &user_data_dir);
-  return user_data_dir.Append(FILE_PATH_LITERAL("Service Process.Lock"));
+  return user_data_dir.Append(FILE_PATH_LITERAL("Service Process Lock"));
+}
+
+#if defined(OS_WIN)
+static std::wstring GetServiceProcessEventName(
+    ServiceProcessType type) {
+  FilePath path = GetServiceProcessLockFilePath(type);
+  std::wstring event_name = path.value();
+  std::replace(event_name.begin(), event_name.end(), '\\', '!');
+  return event_name;
 }
 
-bool CreateServiceProcessLockFile(ServiceProcessType type) {
+// An event that is signaled when a service process is running. This
+// variable is used only in the service process.
+static ScopedHandle service_process_running_event;
+#endif
+
+void SignalServiceProcessRunning(ServiceProcessType type) {
+#if defined(OS_WIN)
+  std::wstring event_name = GetServiceProcessEventName(type);
+  service_process_running_event.Set(
+      CreateEvent(NULL, true, true, event_name.c_str()));
+  DCHECK(service_process_running_event.IsValid());
+#else
+  // TODO(hclam): Implement better mechanism for these platform.
   const FilePath path = GetServiceProcessLockFilePath(type);
   FILE* file = file_util::OpenFile(path, "wb+");
   if (!file)
-    return false;
+    return;
   LOG(INFO) << "Created Service Process lock file: " << path.value();
-  return file_util::TruncateFile(file) && file_util::CloseFile(file);
+  file_util::TruncateFile(file) && file_util::CloseFile(file);
+#endif
 }
 
-bool DeleteServiceProcessLockFile(ServiceProcessType type) {
+void SignalServiceProcessStopped(ServiceProcessType type) {
+#if defined(OS_WIN)
+  // Close the handle to the event.
+  service_process_running_event.Close();
+#else
+  // TODO(hclam): Implement better mechanism for these platform.
   const FilePath path = GetServiceProcessLockFilePath(type);
-  return file_util::Delete(path, false);
+  file_util::Delete(path, false);
+#endif
 }
 
 bool CheckServiceProcessRunning(ServiceProcessType type) {
+#if defined(OS_WIN)
+  std::wstring event_name = GetServiceProcessEventName(type);
+  ScopedHandle event(
+      OpenEvent(SYNCHRONIZE | READ_CONTROL, false, event_name.c_str()));
+  if (!event.IsValid())
+    return false;
+  // Check if the event is signaled.
+  return WaitForSingleObject(event, 0) == WAIT_OBJECT_0;
+#else
+  // TODO(hclam): Implement better mechanism for these platform.
   const FilePath path = GetServiceProcessLockFilePath(type);
   return file_util::PathExists(path);
+#endif
 }