system_wrappers/source/thread_posix.cc - platform/external/chromium_org/third_party/webrtc - Git at Google

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */

 // The state of a thread is controlled by the two member variables
 // alive_ and dead_.
 // alive_ represents the state the thread has been ordered to achieve.
 // It is set to true by the thread at startup, and is set to false by
 // other threads, using SetNotAlive() and Stop().
 // dead_ represents the state the thread has achieved.
 // It is written by the thread encapsulated by this class only
 // (except at init). It is read only by the Stop() method.
 // The Run() method fires event_ when it's started; this ensures that the
 // Start() method does not continue until after dead_ is false.
 // This protects against premature Stop() calls from the creator thread, but
 // not from other threads.

 // Their transitions and states:
 // alive_    dead_  Set by
 // false     true   Constructor
 // true      false  Run() method entry
 // false     any    Run() method run_function failure
 // any       false  Run() method exit (happens only with alive_ false)
 // false     any    SetNotAlive
 // false     any    Stop         Stop waits for dead_ to become true.
 //
 // Summarized a different way:
 // Variable   Writer               Reader
 // alive_     Constructor(false)   Run.loop
 //            Run.start(true)
 //            Run.fail(false)
 //            SetNotAlive(false)
 //            Stop(false)
 //
 // dead_      Constructor(true)    Stop.loop
 //            Run.start(false)
 //            Run.exit(true)

 #include "webrtc/system_wrappers/source/thread_posix.h"

 #include <algorithm>

 #include <assert.h>
 #include <errno.h>
 #include <string.h>  // strncpy
 #include <unistd.h>
 #ifdef WEBRTC_LINUX
 #include <linux/unistd.h>
 #include <sched.h>
 #include <sys/prctl.h>
 #include <sys/syscall.h>
 #include <sys/types.h>
 #endif

 #include "webrtc/system_wrappers/interface/critical_section_wrapper.h"
 #include "webrtc/system_wrappers/interface/event_wrapper.h"
 #include "webrtc/system_wrappers/interface/sleep.h"
 #include "webrtc/system_wrappers/interface/trace.h"

 namespace webrtc {

 int ConvertToSystemPriority(ThreadPriority priority, int min_prio,
                             int max_prio) {
   assert(max_prio - min_prio > 2);
   const int top_prio = max_prio - 1;
   const int low_prio = min_prio + 1;

   switch (priority) {
     case kLowPriority:
       return low_prio;
     case kNormalPriority:
       // The -1 ensures that the kHighPriority is always greater or equal to
       // kNormalPriority.
       return (low_prio + top_prio - 1) / 2;
     case kHighPriority:
       return std::max(top_prio - 2, low_prio);
     case kHighestPriority:
       return std::max(top_prio - 1, low_prio);
     case kRealtimePriority:
       return top_prio;
   }
   assert(false);
   return low_prio;
 }

 extern "C"
 {
   static void* StartThread(void* lp_parameter) {
     static_cast<ThreadPosix*>(lp_parameter)->Run();
     return 0;
   }
 }

 ThreadWrapper* ThreadPosix::Create(ThreadRunFunction func, ThreadObj obj,
                                    ThreadPriority prio,
                                    const char* thread_name) {
   ThreadPosix* ptr = new ThreadPosix(func, obj, prio, thread_name);
   if (!ptr) {
     return NULL;
   }
   const int error = ptr->Construct();
   if (error) {
     delete ptr;
     return NULL;
   }
   return ptr;
 }

 ThreadPosix::ThreadPosix(ThreadRunFunction func, ThreadObj obj,
                          ThreadPriority prio, const char* thread_name)
     : run_function_(func),
       obj_(obj),
       crit_state_(CriticalSectionWrapper::CreateCriticalSection()),
       alive_(false),
       dead_(true),
       prio_(prio),
       event_(EventWrapper::Create()),
       name_(),
       set_thread_name_(false),
 #if (defined(WEBRTC_LINUX) || defined(WEBRTC_ANDROID))
       pid_(-1),
 #endif
       attr_(),
       thread_(0) {
   if (thread_name != NULL) {
     set_thread_name_ = true;
     strncpy(name_, thread_name, kThreadMaxNameLength);
     name_[kThreadMaxNameLength - 1] = '\0';
   }
 }

 uint32_t ThreadWrapper::GetThreadId() {
 #if defined(WEBRTC_ANDROID) || defined(WEBRTC_LINUX)
   return static_cast<uint32_t>(syscall(__NR_gettid));
 #elif defined(WEBRTC_MAC) || defined(WEBRTC_IOS)
   return pthread_mach_thread_np(pthread_self());
 #else
   return reinterpret_cast<uint32_t>(pthread_self());
 #endif
 }

 int ThreadPosix::Construct() {
   int result = 0;
 #if !defined(WEBRTC_ANDROID)
   // Enable immediate cancellation if requested, see Shutdown().
   result = pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
   if (result != 0) {
     return -1;
   }
   result = pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL);
   if (result != 0) {
     return -1;
   }
 #endif
   result = pthread_attr_init(&attr_);
   if (result != 0) {
     return -1;
   }
   return 0;
 }

 ThreadPosix::~ThreadPosix() {
   pthread_attr_destroy(&attr_);
   delete event_;
   delete crit_state_;
 }

 #define HAS_THREAD_ID !defined(WEBRTC_IOS) && !defined(WEBRTC_MAC)

 bool ThreadPosix::Start(unsigned int& thread_id)
 {
   int result = pthread_attr_setdetachstate(&attr_, PTHREAD_CREATE_DETACHED);
   // Set the stack stack size to 1M.
   result |= pthread_attr_setstacksize(&attr_, 1024 * 1024);
 #ifdef WEBRTC_THREAD_RR
   const int policy = SCHED_RR;
 #else
   const int policy = SCHED_FIFO;
 #endif
   event_->Reset();
   // If pthread_create was successful, a thread was created and is running.
   // Don't return false if it was successful since if there are any other
   // failures the state will be: thread was started but not configured as
   // asked for. However, the caller of this API will assume that a false
   // return value means that the thread never started.
   result |= pthread_create(&thread_, &attr_, &StartThread, this);
   if (result != 0) {
     return false;
   }
   {
     CriticalSectionScoped cs(crit_state_);
     dead_ = false;
   }

   // Wait up to 10 seconds for the OS to call the callback function. Prevents
   // race condition if Stop() is called too quickly after start.
   if (kEventSignaled != event_->Wait(WEBRTC_EVENT_10_SEC)) {
     WEBRTC_TRACE(kTraceError, kTraceUtility, -1,
                  "posix thread event never triggered");
     // Timed out. Something went wrong.
     return true;
   }

 #if HAS_THREAD_ID
   thread_id = static_cast<unsigned int>(thread_);
 #endif
   sched_param param;

   const int min_prio = sched_get_priority_min(policy);
   const int max_prio = sched_get_priority_max(policy);

   if ((min_prio == EINVAL) || (max_prio == EINVAL)) {
     WEBRTC_TRACE(kTraceError, kTraceUtility, -1,
                  "unable to retreive min or max priority for threads");
     return true;
   }
   if (max_prio - min_prio <= 2) {
     // There is no room for setting priorities with any granularity.
     return true;
   }
   param.sched_priority = ConvertToSystemPriority(prio_, min_prio, max_prio);
   result = pthread_setschedparam(thread_, policy, &param);
   if (result == EINVAL) {
     WEBRTC_TRACE(kTraceError, kTraceUtility, -1,
                  "unable to set thread priority");
   }
   return true;
 }

 // CPU_ZERO and CPU_SET are not available in NDK r7, so disable
 // SetAffinity on Android for now.
 #if (defined(WEBRTC_LINUX) && (!defined(WEBRTC_ANDROID)))
 bool ThreadPosix::SetAffinity(const int* processor_numbers,
                               const unsigned int amount_of_processors) {
   if (!processor_numbers || (amount_of_processors == 0)) {
     return false;
   }
   cpu_set_t mask;
   CPU_ZERO(&mask);

   for (unsigned int processor = 0;
        processor < amount_of_processors;
        ++processor) {
     CPU_SET(processor_numbers[processor], &mask);
   }
 #if defined(WEBRTC_ANDROID)
   // Android.
   const int result = syscall(__NR_sched_setaffinity,
                              pid_,
                              sizeof(mask),
                              &mask);
 #else
   // "Normal" Linux.
   const int result = sched_setaffinity(pid_,
                                        sizeof(mask),
                                        &mask);
 #endif
   if (result != 0) {
     return false;
   }
   return true;
 }

 #else
 // NOTE: On Mac OS X, use the Thread affinity API in
 // /usr/include/mach/thread_policy.h: thread_policy_set and mach_thread_self()
 // instead of Linux gettid() syscall.
 bool ThreadPosix::SetAffinity(const int* , const unsigned int) {
   return false;
 }
 #endif

 void ThreadPosix::SetNotAlive() {
   CriticalSectionScoped cs(crit_state_);
   alive_ = false;
 }

 bool ThreadPosix::Stop() {
   bool dead = false;
   {
     CriticalSectionScoped cs(crit_state_);
     alive_ = false;
     dead = dead_;
   }

   // TODO(hellner) why not use an event here?
   // Wait up to 10 seconds for the thread to terminate
   for (int i = 0; i < 1000 && !dead; ++i) {
     SleepMs(10);
     {
       CriticalSectionScoped cs(crit_state_);
       dead = dead_;
     }
   }
   if (dead) {
     return true;
   } else {
     return false;
   }
 }

 void ThreadPosix::Run() {
   {
     CriticalSectionScoped cs(crit_state_);
     alive_ = true;
   }
 #if (defined(WEBRTC_LINUX) || defined(WEBRTC_ANDROID))
   pid_ = GetThreadId();
 #endif
   // The event the Start() is waiting for.
   event_->Set();

   if (set_thread_name_) {
 #ifdef WEBRTC_LINUX
     prctl(PR_SET_NAME, (unsigned long)name_, 0, 0, 0);
 #endif
     WEBRTC_TRACE(kTraceStateInfo, kTraceUtility, -1,
                  "Thread with name:%s started ", name_);
   } else {
     WEBRTC_TRACE(kTraceStateInfo, kTraceUtility, -1,
                  "Thread without name started");
   }
   bool alive = true;
   bool run = true;
   while (alive) {
     run = run_function_(obj_);
     CriticalSectionScoped cs(crit_state_);
     if (!run) {
       alive_ = false;
     }
     alive = alive_;
   }

   if (set_thread_name_) {
     // Don't set the name for the trace thread because it may cause a
     // deadlock. TODO(hellner) there should be a better solution than
     // coupling the thread and the trace class like this.
     if (strcmp(name_, "Trace")) {
       WEBRTC_TRACE(kTraceStateInfo, kTraceUtility, -1,
                    "Thread with name:%s stopped", name_);
     }
   } else {
     WEBRTC_TRACE(kTraceStateInfo, kTraceUtility, -1,
                  "Thread without name stopped");
   }
   {
     CriticalSectionScoped cs(crit_state_);
     dead_ = true;
   }
 }

 }  // namespace webrtc
	/*
	* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
	*
	* Use of this source code is governed by a BSD-style license
	* that can be found in the LICENSE file in the root of the source
	* tree. An additional intellectual property rights grant can be found
	* in the file PATENTS. All contributing project authors may
	* be found in the AUTHORS file in the root of the source tree.
	*/

	// The state of a thread is controlled by the two member variables
	// alive_ and dead_.
	// alive_ represents the state the thread has been ordered to achieve.
	// It is set to true by the thread at startup, and is set to false by
	// other threads, using SetNotAlive() and Stop().
	// dead_ represents the state the thread has achieved.
	// It is written by the thread encapsulated by this class only
	// (except at init). It is read only by the Stop() method.
	// The Run() method fires event_ when it's started; this ensures that the
	// Start() method does not continue until after dead_ is false.
	// This protects against premature Stop() calls from the creator thread, but
	// not from other threads.

	// Their transitions and states:
	// alive_ dead_ Set by
	// false true Constructor
	// true false Run() method entry
	// false any Run() method run_function failure
	// any false Run() method exit (happens only with alive_ false)
	// false any SetNotAlive
	// false any Stop Stop waits for dead_ to become true.
	//
	// Summarized a different way:
	// Variable Writer Reader
	// alive_ Constructor(false) Run.loop
	// Run.start(true)
	// Run.fail(false)
	// SetNotAlive(false)
	// Stop(false)
	//
	// dead_ Constructor(true) Stop.loop
	// Run.start(false)
	// Run.exit(true)

	#include "webrtc/system_wrappers/source/thread_posix.h"

	#include <algorithm>

	#include <assert.h>
	#include <errno.h>
	#include <string.h> // strncpy
	#include <unistd.h>
	#ifdef WEBRTC_LINUX
	#include <linux/unistd.h>
	#include <sched.h>
	#include <sys/prctl.h>
	#include <sys/syscall.h>
	#include <sys/types.h>
	#endif

	#include "webrtc/system_wrappers/interface/critical_section_wrapper.h"
	#include "webrtc/system_wrappers/interface/event_wrapper.h"
	#include "webrtc/system_wrappers/interface/sleep.h"
	#include "webrtc/system_wrappers/interface/trace.h"

	namespace webrtc {

	int ConvertToSystemPriority(ThreadPriority priority, int min_prio,
	int max_prio) {
	assert(max_prio - min_prio > 2);
	const int top_prio = max_prio - 1;
	const int low_prio = min_prio + 1;

	switch (priority) {
	case kLowPriority:
	return low_prio;
	case kNormalPriority:
	// The -1 ensures that the kHighPriority is always greater or equal to
	// kNormalPriority.
	return (low_prio + top_prio - 1) / 2;
	case kHighPriority:
	return std::max(top_prio - 2, low_prio);
	case kHighestPriority:
	return std::max(top_prio - 1, low_prio);
	case kRealtimePriority:
	return top_prio;
	}
	assert(false);
	return low_prio;
	}

	extern "C"
	{
	static void* StartThread(void* lp_parameter) {
	static_cast<ThreadPosix*>(lp_parameter)->Run();
	return 0;
	}
	}

	ThreadWrapper* ThreadPosix::Create(ThreadRunFunction func, ThreadObj obj,
	ThreadPriority prio,
	const char* thread_name) {
	ThreadPosix* ptr = new ThreadPosix(func, obj, prio, thread_name);
	if (!ptr) {
	return NULL;
	}
	const int error = ptr->Construct();
	if (error) {
	delete ptr;
	return NULL;
	}
	return ptr;
	}

	ThreadPosix::ThreadPosix(ThreadRunFunction func, ThreadObj obj,
	ThreadPriority prio, const char* thread_name)
	: run_function_(func),
	obj_(obj),
	crit_state_(CriticalSectionWrapper::CreateCriticalSection()),
	alive_(false),
	dead_(true),
	prio_(prio),
	event_(EventWrapper::Create()),
	name_(),
	set_thread_name_(false),
	#if (defined(WEBRTC_LINUX) \|\| defined(WEBRTC_ANDROID))
	pid_(-1),
	#endif
	attr_(),
	thread_(0) {
	if (thread_name != NULL) {
	set_thread_name_ = true;
	strncpy(name_, thread_name, kThreadMaxNameLength);
	name_[kThreadMaxNameLength - 1] = '\0';
	}
	}

	uint32_t ThreadWrapper::GetThreadId() {
	#if defined(WEBRTC_ANDROID) \|\| defined(WEBRTC_LINUX)
	return static_cast<uint32_t>(syscall(__NR_gettid));
	#elif defined(WEBRTC_MAC) \|\| defined(WEBRTC_IOS)
	return pthread_mach_thread_np(pthread_self());
	#else
	return reinterpret_cast<uint32_t>(pthread_self());
	#endif
	}

	int ThreadPosix::Construct() {
	int result = 0;
	#if !defined(WEBRTC_ANDROID)
	// Enable immediate cancellation if requested, see Shutdown().
	result = pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
	if (result != 0) {
	return -1;
	}
	result = pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL);
	if (result != 0) {
	return -1;
	}
	#endif
	result = pthread_attr_init(&attr_);
	if (result != 0) {
	return -1;
	}
	return 0;
	}

	ThreadPosix::~ThreadPosix() {
	pthread_attr_destroy(&attr_);
	delete event_;
	delete crit_state_;
	}

	#define HAS_THREAD_ID !defined(WEBRTC_IOS) && !defined(WEBRTC_MAC)

	bool ThreadPosix::Start(unsigned int& thread_id)
	{
	int result = pthread_attr_setdetachstate(&attr_, PTHREAD_CREATE_DETACHED);
	// Set the stack stack size to 1M.
	result \|= pthread_attr_setstacksize(&attr_, 1024 * 1024);
	#ifdef WEBRTC_THREAD_RR
	const int policy = SCHED_RR;
	#else
	const int policy = SCHED_FIFO;
	#endif
	event_->Reset();
	// If pthread_create was successful, a thread was created and is running.
	// Don't return false if it was successful since if there are any other
	// failures the state will be: thread was started but not configured as
	// asked for. However, the caller of this API will assume that a false
	// return value means that the thread never started.
	result \|= pthread_create(&thread_, &attr_, &StartThread, this);
	if (result != 0) {
	return false;
	}
	{
	CriticalSectionScoped cs(crit_state_);
	dead_ = false;
	}

	// Wait up to 10 seconds for the OS to call the callback function. Prevents
	// race condition if Stop() is called too quickly after start.
	if (kEventSignaled != event_->Wait(WEBRTC_EVENT_10_SEC)) {
	WEBRTC_TRACE(kTraceError, kTraceUtility, -1,
	"posix thread event never triggered");
	// Timed out. Something went wrong.
	return true;
	}

	#if HAS_THREAD_ID
	thread_id = static_cast<unsigned int>(thread_);
	#endif
	sched_param param;

	const int min_prio = sched_get_priority_min(policy);
	const int max_prio = sched_get_priority_max(policy);

	if ((min_prio == EINVAL) \|\| (max_prio == EINVAL)) {
	WEBRTC_TRACE(kTraceError, kTraceUtility, -1,
	"unable to retreive min or max priority for threads");
	return true;
	}
	if (max_prio - min_prio <= 2) {
	// There is no room for setting priorities with any granularity.
	return true;
	}
	param.sched_priority = ConvertToSystemPriority(prio_, min_prio, max_prio);
	result = pthread_setschedparam(thread_, policy, &param);
	if (result == EINVAL) {
	WEBRTC_TRACE(kTraceError, kTraceUtility, -1,
	"unable to set thread priority");
	}
	return true;
	}

	// CPU_ZERO and CPU_SET are not available in NDK r7, so disable
	// SetAffinity on Android for now.
	#if (defined(WEBRTC_LINUX) && (!defined(WEBRTC_ANDROID)))
	bool ThreadPosix::SetAffinity(const int* processor_numbers,
	const unsigned int amount_of_processors) {
	if (!processor_numbers \|\| (amount_of_processors == 0)) {
	return false;
	}
	cpu_set_t mask;
	CPU_ZERO(&mask);

	for (unsigned int processor = 0;
	processor < amount_of_processors;
	++processor) {
	CPU_SET(processor_numbers[processor], &mask);
	}
	#if defined(WEBRTC_ANDROID)
	// Android.
	const int result = syscall(__NR_sched_setaffinity,
	pid_,
	sizeof(mask),
	&mask);
	#else
	// "Normal" Linux.
	const int result = sched_setaffinity(pid_,
	sizeof(mask),
	&mask);
	#endif
	if (result != 0) {
	return false;
	}
	return true;
	}

	#else
	// NOTE: On Mac OS X, use the Thread affinity API in
	// /usr/include/mach/thread_policy.h: thread_policy_set and mach_thread_self()
	// instead of Linux gettid() syscall.
	bool ThreadPosix::SetAffinity(const int* , const unsigned int) {
	return false;
	}
	#endif

	void ThreadPosix::SetNotAlive() {
	CriticalSectionScoped cs(crit_state_);
	alive_ = false;
	}

	bool ThreadPosix::Stop() {
	bool dead = false;
	{
	CriticalSectionScoped cs(crit_state_);
	alive_ = false;
	dead = dead_;
	}

	// TODO(hellner) why not use an event here?
	// Wait up to 10 seconds for the thread to terminate
	for (int i = 0; i < 1000 && !dead; ++i) {
	SleepMs(10);
	{
	CriticalSectionScoped cs(crit_state_);
	dead = dead_;
	}
	}
	if (dead) {
	return true;
	} else {
	return false;
	}
	}

	void ThreadPosix::Run() {
	{
	CriticalSectionScoped cs(crit_state_);
	alive_ = true;
	}
	#if (defined(WEBRTC_LINUX) \|\| defined(WEBRTC_ANDROID))
	pid_ = GetThreadId();
	#endif
	// The event the Start() is waiting for.
	event_->Set();

	if (set_thread_name_) {
	#ifdef WEBRTC_LINUX
	prctl(PR_SET_NAME, (unsigned long)name_, 0, 0, 0);
	#endif
	WEBRTC_TRACE(kTraceStateInfo, kTraceUtility, -1,
	"Thread with name:%s started ", name_);
	} else {
	WEBRTC_TRACE(kTraceStateInfo, kTraceUtility, -1,
	"Thread without name started");
	}
	bool alive = true;
	bool run = true;
	while (alive) {
	run = run_function_(obj_);
	CriticalSectionScoped cs(crit_state_);
	if (!run) {
	alive_ = false;
	}
	alive = alive_;
	}

	if (set_thread_name_) {
	// Don't set the name for the trace thread because it may cause a
	// deadlock. TODO(hellner) there should be a better solution than
	// coupling the thread and the trace class like this.
	if (strcmp(name_, "Trace")) {
	WEBRTC_TRACE(kTraceStateInfo, kTraceUtility, -1,
	"Thread with name:%s stopped", name_);
	}
	} else {
	WEBRTC_TRACE(kTraceStateInfo, kTraceUtility, -1,
	"Thread without name stopped");
	}
	{
	CriticalSectionScoped cs(crit_state_);
	dead_ = true;
	}
	}

	} // namespace webrtc