A place to store the pid->mach_port_t mapping.

Not yet for review.

Landing to measure perf impact, will revert immediately.

BUG=13156
TEST=unittests

Review URL: http://codereview.chromium.org/460126

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@34146 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 81 insertions, 0 deletions

diff --git a/chrome/browser/mach_broker_mac.h b/chrome/browser/mach_broker_mac.h
new file mode 100644
index 0000000..5672db5
--- /dev/null
+++ b/chrome/browser/mach_broker_mac.h
@@ -0,0 +1,81 @@
+// Copyright (c) 2009 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.
+
+#ifndef CHROME_BROWSER_MACH_BROKER_H_
+#define CHROME_BROWSER_MACH_BROKER_H_
+
+#include <map>
+
+#include <mach/mach.h>
+
+#include "base/lock.h"
+#include "base/process.h"
+#include "base/singleton.h"
+
+// On OS X, the mach_port_t of a process is required to collect metrics about
+// the process. Running |task_for_pid()| is only allowed for priviledged code.
+// However, a process has port rights to all its subprocesses, so let the
+// browser's child processes send their mach_port_t to the browser over IPC.
+// This way, the brower can at least collect metrics of its child processes,
+// which is what it's most interested in anyway.
+//
+// mach_port_ts can only be sent over mach ipc, not over the socketpair that
+// the regular ipc system uses. Hence, the child processes open a mach
+// connection shortly after launching and ipc their mach data to the browser
+// process. This data is kept in a global |MachBroker| object.
+//
+// Due to this data arriving over a separate channel, it is not available
+// immediately after a child process has been started.
+class MachBroker {
+ public:
+  // Returns the global MachBroker.
+  static MachBroker* instance();
+
+  // Returns the mach task belonging to |pid|, or 0 if no mach task is
+  // registered for |pid|.
+  mach_port_t MachTaskForPid(base::ProcessHandle pid) const;
+
+  // Returns the mach host belonging to |pid|, or 0 if no mach task is
+  // registered for |pid|.
+  mach_port_t MachHostForPid(base::ProcessHandle pid) const;
+
+  struct MachInfo {
+    MachInfo() : mach_task_(0), mach_host_(0) {}
+
+    MachInfo& SetTask(mach_port_t task) {
+      mach_task_ = task;
+      return *this;
+    }
+
+    MachInfo& SetHost(mach_port_t host) {
+      mach_host_ = host;
+      return *this;
+    }
+
+    mach_port_t mach_task_;
+    mach_port_t mach_host_;
+  };
+
+  // Adds mach info for a given pid.
+  void RegisterPid(base::ProcessHandle pid, const MachInfo& mach_info);
+
+  // Removes all mappings belonging to |pid| from the broker.
+  void Invalidate(base::ProcessHandle pid);
+
+ private:
+  // Private constructor.
+  MachBroker();
+  friend struct DefaultSingletonTraits<MachBroker>;
+  friend class MachBrokerTest;
+
+  // Stores
+  typedef std::map<base::ProcessHandle, MachInfo> MachMap;
+  MachMap mach_map_;
+
+  // Mutex that guards |mach_map_|.
+  mutable Lock lock_;
+};
+
+#endif  // CHROME_BROWSER_MACH_BROKER_H_
+