michael@0: // Copyright (c) 2012 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: // WARNING: You should *NOT* be using this class directly.  PlatformThread is
michael@0: // the low-level platform-specific abstraction to the OS's threading interface.
michael@0: // You should instead be using a message-loop driven Thread, see thread.h.
michael@0: 
michael@0: #ifndef BASE_THREADING_PLATFORM_THREAD_H_
michael@0: #define BASE_THREADING_PLATFORM_THREAD_H_
michael@0: 
michael@0: #include "base/base_export.h"
michael@0: #include "base/basictypes.h"
michael@0: #include "base/time/time.h"
michael@0: #include "build/build_config.h"
michael@0: 
michael@0: #if defined(OS_WIN)
michael@0: #include <windows.h>
michael@0: #elif defined(OS_POSIX)
michael@0: #include <pthread.h>
michael@0: #include <unistd.h>
michael@0: #endif
michael@0: 
michael@0: namespace base {
michael@0: 
michael@0: #if defined(OS_WIN)
michael@0: typedef DWORD PlatformThreadId;
michael@0: #elif defined(OS_POSIX)
michael@0: typedef pid_t PlatformThreadId;
michael@0: #endif
michael@0: 
michael@0: class PlatformThreadHandle {
michael@0:  public:
michael@0: #if defined(OS_WIN)
michael@0:   typedef void* Handle;
michael@0: #elif defined(OS_POSIX)
michael@0:   typedef pthread_t Handle;
michael@0: #endif
michael@0: 
michael@0:   PlatformThreadHandle()
michael@0:       : handle_(0),
michael@0:         id_(0) {
michael@0:   }
michael@0: 
michael@0:   explicit PlatformThreadHandle(Handle handle)
michael@0:       : handle_(handle),
michael@0:         id_(0) {
michael@0:   }
michael@0: 
michael@0:   PlatformThreadHandle(Handle handle,
michael@0:                        PlatformThreadId id)
michael@0:       : handle_(handle),
michael@0:         id_(id) {
michael@0:   }
michael@0: 
michael@0:   bool is_equal(const PlatformThreadHandle& other) {
michael@0:     return handle_ == other.handle_;
michael@0:   }
michael@0: 
michael@0:   bool is_null() {
michael@0:     return !handle_;
michael@0:   }
michael@0: 
michael@0:   Handle platform_handle() {
michael@0:     return handle_;
michael@0:   }
michael@0: 
michael@0:  private:
michael@0:   friend class PlatformThread;
michael@0: 
michael@0:   Handle handle_;
michael@0:   PlatformThreadId id_;
michael@0: };
michael@0: 
michael@0: const PlatformThreadId kInvalidThreadId(0);
michael@0: 
michael@0: // Valid values for SetThreadPriority()
michael@0: enum ThreadPriority{
michael@0:   kThreadPriority_Normal,
michael@0:   // Suitable for low-latency, glitch-resistant audio.
michael@0:   kThreadPriority_RealtimeAudio,
michael@0:   // Suitable for threads which generate data for the display (at ~60Hz).
michael@0:   kThreadPriority_Display,
michael@0:   // Suitable for threads that shouldn't disrupt high priority work.
michael@0:   kThreadPriority_Background
michael@0: };
michael@0: 
michael@0: // A namespace for low-level thread functions.
michael@0: class BASE_EXPORT PlatformThread {
michael@0:  public:
michael@0:   // Implement this interface to run code on a background thread.  Your
michael@0:   // ThreadMain method will be called on the newly created thread.
michael@0:   class BASE_EXPORT Delegate {
michael@0:    public:
michael@0:     virtual void ThreadMain() = 0;
michael@0: 
michael@0:    protected:
michael@0:     virtual ~Delegate() {}
michael@0:   };
michael@0: 
michael@0:   // Gets the current thread id, which may be useful for logging purposes.
michael@0:   static PlatformThreadId CurrentId();
michael@0: 
michael@0:   // Get the current handle.
michael@0:   static PlatformThreadHandle CurrentHandle();
michael@0: 
michael@0:   // Yield the current thread so another thread can be scheduled.
michael@0:   static void YieldCurrentThread();
michael@0: 
michael@0:   // Sleeps for the specified duration.
michael@0:   static void Sleep(base::TimeDelta duration);
michael@0: 
michael@0:   // Sets the thread name visible to debuggers/tools. This has no effect
michael@0:   // otherwise. This name pointer is not copied internally. Thus, it must stay
michael@0:   // valid until the thread ends.
michael@0:   static void SetName(const char* name);
michael@0: 
michael@0:   // Gets the thread name, if previously set by SetName.
michael@0:   static const char* GetName();
michael@0: 
michael@0:   // Creates a new thread.  The |stack_size| parameter can be 0 to indicate
michael@0:   // that the default stack size should be used.  Upon success,
michael@0:   // |*thread_handle| will be assigned a handle to the newly created thread,
michael@0:   // and |delegate|'s ThreadMain method will be executed on the newly created
michael@0:   // thread.
michael@0:   // NOTE: When you are done with the thread handle, you must call Join to
michael@0:   // release system resources associated with the thread.  You must ensure that
michael@0:   // the Delegate object outlives the thread.
michael@0:   static bool Create(size_t stack_size, Delegate* delegate,
michael@0:                      PlatformThreadHandle* thread_handle);
michael@0: 
michael@0:   // CreateWithPriority() does the same thing as Create() except the priority of
michael@0:   // the thread is set based on |priority|.  Can be used in place of Create()
michael@0:   // followed by SetThreadPriority().  SetThreadPriority() has not been
michael@0:   // implemented on the Linux platform yet, this is the only way to get a high
michael@0:   // priority thread on Linux.
michael@0:   static bool CreateWithPriority(size_t stack_size, Delegate* delegate,
michael@0:                                  PlatformThreadHandle* thread_handle,
michael@0:                                  ThreadPriority priority);
michael@0: 
michael@0:   // CreateNonJoinable() does the same thing as Create() except the thread
michael@0:   // cannot be Join()'d.  Therefore, it also does not output a
michael@0:   // PlatformThreadHandle.
michael@0:   static bool CreateNonJoinable(size_t stack_size, Delegate* delegate);
michael@0: 
michael@0:   // Joins with a thread created via the Create function.  This function blocks
michael@0:   // the caller until the designated thread exits.  This will invalidate
michael@0:   // |thread_handle|.
michael@0:   static void Join(PlatformThreadHandle thread_handle);
michael@0: 
michael@0:   static void SetThreadPriority(PlatformThreadHandle handle,
michael@0:                                 ThreadPriority priority);
michael@0: 
michael@0:  private:
michael@0:   DISALLOW_IMPLICIT_CONSTRUCTORS(PlatformThread);
michael@0: };
michael@0: 
michael@0: }  // namespace base
michael@0: 
michael@0: #endif  // BASE_THREADING_PLATFORM_THREAD_H_