ipc/chromium/src/base/platform_thread.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
   4 // Use of this source code is governed by a BSD-style license that can be
   5 // found in the LICENSE file.
   6
   7 // WARNING: You should *NOT* be using this class directly.  PlatformThread is
   8 // the low-level platform-specific abstraction to the OS's threading interface.
   9 // You should instead be using a message-loop driven Thread, see thread.h.
  10
  11 #ifndef BASE_PLATFORM_THREAD_H_
  12 #define BASE_PLATFORM_THREAD_H_
  13
  14 #include "base/basictypes.h"
  15
  16 // PlatformThreadHandle should not be assumed to be a numeric type, since the
  17 // standard intends to allow pthread_t to be a structure.  This means you
  18 // should not initialize it to a value, like 0.  If it's a member variable, the
  19 // constructor can safely "value initialize" using () in the initializer list.
  20 #if defined(XP_WIN)
  21 #  include <windows.h>
  22 typedef DWORD PlatformThreadId;
  23 typedef void* PlatformThreadHandle;  // HANDLE
  24 #else
  25 #  include <pthread.h>
  26 typedef pthread_t PlatformThreadHandle;
  27 #  if defined(XP_LINUX) || defined(XP_OPENBSD) || defined(XP_SOLARIS) || \
  28       defined(__GLIBC__)
  29 #    include <unistd.h>
  30 typedef pid_t PlatformThreadId;
  31 #  elif defined(__DragonFly__) || defined(XP_FREEBSD) || defined(XP_NETBSD)
  32 #    include <sys/types.h>
  33 typedef lwpid_t PlatformThreadId;
  34 #  elif defined(XP_DARWIN)
  35 #    include <mach/mach.h>
  36 typedef mach_port_t PlatformThreadId;
  37 #  endif
  38 #endif
  39
  40 // A namespace for low-level thread functions.
  41 class PlatformThread {
  42  public:
  43   // Gets the current thread id, which may be useful for logging purposes.
  44   static PlatformThreadId CurrentId();
  45
  46   // Yield the current thread so another thread can be scheduled.
  47   static void YieldCurrentThread();
  48
  49   // Sleeps for the specified duration (units are milliseconds).
  50   static void Sleep(int duration_ms);
  51
  52   // Sets the thread name visible to a debugger.  This has no effect otherwise.
  53   static void SetName(const char* name);
  54
  55   // Implement this interface to run code on a background thread.  Your
  56   // ThreadMain method will be called on the newly created thread.
  57   class Delegate {
  58    public:
  59     virtual ~Delegate() {}
  60     virtual void ThreadMain() = 0;
  61   };
  62
  63   // Creates a new thread.  The |stack_size| parameter can be 0 to indicate
  64   // that the default stack size should be used.  Upon success,
  65   // |*thread_handle| will be assigned a handle to the newly created thread,
  66   // and |delegate|'s ThreadMain method will be executed on the newly created
  67   // thread.
  68   // NOTE: When you are done with the thread handle, you must call Join to
  69   // release system resources associated with the thread.  You must ensure that
  70   // the Delegate object outlives the thread.
  71   static bool Create(size_t stack_size, Delegate* delegate,
  72                      PlatformThreadHandle* thread_handle);
  73
  74   // CreateNonJoinable() does the same thing as Create() except the thread
  75   // cannot be Join()'d.  Therefore, it also does not output a
  76   // PlatformThreadHandle.
  77   static bool CreateNonJoinable(size_t stack_size, Delegate* delegate);
  78
  79   // Joins with a thread created via the Create function.  This function blocks
  80   // the caller until the designated thread exits.  This will invalidate
  81   // |thread_handle|.
  82   static void Join(PlatformThreadHandle thread_handle);
  83
  84  private:
  85   DISALLOW_IMPLICIT_CONSTRUCTORS(PlatformThread);
  86 };
  87
  88 #endif  // BASE_PLATFORM_THREAD_H_