--- /dev/null
+
+/*] Copyright (c) 2009-2010, Charles McGarvey [**************************
+**] All rights reserved.
+*
+* vi:ts=4 sw=4 tw=75
+*
+* Distributable under the terms and conditions of the 2-clause BSD license;
+* see the file COPYING for a complete text of the license.
+*
+**************************************************************************/
+
+/**
+ * \file thread.hh
+ * Light C++ wrapper around the SDL threads API.
+ */
+
+#ifndef _MOOF_THREAD_HH_
+#define _MOOF_THREAD_HH_
+
+#include <boost/bind.hpp>
+#include <boost/function.hpp>
+#include <SDL/SDL.h>
+
+#include <moof/math.hh>
+
+
+namespace moof {
+
+
+/**
+ * Represents a thread which may be running. You cannot instantiate a
+ * thread object directly; new threads are created by detaching functions
+ * using the detach() method. Once a thread is detached, it will continue
+ * running until the function returns. You don't need to keep the thread
+ * object you want to wait() or kill() the thread later.
+ */
+class thread
+{
+public:
+
+ typedef boost::function<int(void)> function;
+
+
+ /**
+ * Construct an invalid thread object which has no association with any
+ * real thread.
+ */
+ thread() :
+ thread_(0) {}
+
+ /**
+ * Execute a function in a new thread.
+ * \param function The function to execute.
+ * \return The new thread, or an invalid thread if an error occurred.
+ */
+ static thread detach(const function& function)
+ {
+ thread::function* fcopy = new thread::function(function);
+ SDL_Thread* thread = SDL_CreateThread(&thread::run, (void*)fcopy);
+ if (thread == 0) delete fcopy;
+ return moof::thread(thread);
+ }
+
+
+ /**
+ * Wait for the thread to terminate, getting its return value. The
+ * thread will be invalidated.
+ * \return The integer value returned by the detached function.
+ */
+ int wait()
+ {
+ int i;
+ SDL_WaitThread(thread_, &i);
+ thread_ = 0;
+ return i;
+ }
+
+ /**
+ * Forcefully kill the thread without giving it a chance to clean up
+ * after itself. The thread will be invalidated. Don't use this.
+ */
+ void kill()
+ {
+ SDL_KillThread(thread_);
+ thread_ = 0;
+ }
+
+ /**
+ * Get whether or not the thread object is associated with a real
+ * thread.
+ * \return True if the thread is valid, false otherwise.
+ */
+ bool is_valid() const
+ {
+ return thread_ != 0;
+ }
+
+
+ /**
+ * Get a unique identifier for this thread, if it is valid.
+ * \return The identifier.
+ */
+ uint32_t identifier() const
+ {
+ return SDL_GetThreadID(thread_);
+ }
+
+ /**
+ * Get the unique identifier of the calling thread.
+ * \return The identifier.
+ */
+ static uint32_t current_identifier()
+ {
+ return SDL_ThreadID();
+ }
+
+
+private:
+
+ thread(SDL_Thread* thread) :
+ thread_(thread) {}
+
+ static int run(void* arg)
+ {
+ int code = (*(function*)arg)();
+ delete (function*)arg;
+ return code;
+ }
+
+
+ SDL_Thread* thread_;
+};
+
+
+/**
+ * An abstract class representing some task that is to be run
+ * asynchronously.
+ */
+class async_task
+{
+public:
+
+ /**
+ * Deconstruct the task.
+ */
+ virtual ~async_task() {}
+
+ /**
+ * Get whether or not the task is done.
+ * \return True if the task is done, false otherwise.
+ */
+ virtual bool is_done() const = 0;
+
+ /**
+ * Begin the task.
+ */
+ virtual void run() = 0;
+
+ /**
+ * Block the current thread until the task is finished.
+ * \return A value representing the state of the finished task.
+ */
+ virtual int wait() = 0;
+};
+
+/**
+ * An asynchronous task that is run to be executed in a separated thread.
+ */
+class threaded_task
+{
+public:
+
+ /**
+ * Get the thread object the task is executing in.
+ * \return The thread.
+ */
+ const class thread& thread() const { return thread_; }
+
+ /**
+ * Block the current thread until the task thread is finished.
+ * \return The integer value returned by the task function.
+ */
+ int wait()
+ {
+ return thread_.wait();
+ }
+
+
+protected:
+
+ class thread thread_;
+};
+
+
+/**
+ * A mutex to protect sensitive sections of code from threads which might
+ * otherwise cause unpredictable results.
+ */
+class mutex
+{
+public:
+
+ /**
+ * Construct a mutex.
+ */
+ mutex() :
+ mutex_(SDL_CreateMutex()) {}
+
+ /**
+ * Deconstruct a mutex.
+ */
+ ~mutex()
+ {
+ SDL_DestroyMutex(mutex_);
+ }
+
+
+ /**
+ * Block until the calling thread can secure exclusive access to the
+ * code protected by the mutex.
+ * \return True if the lock was acquired, false otherwise.
+ * \see lock
+ */
+ bool acquire_lock()
+ {
+ return (SDL_LockMutex(mutex_) == 0);
+ }
+
+ /**
+ * Unlock the mutex. Call this after the sensitive block of code to
+ * allow another thread to acquire the lock.
+ * \return True if the mutex was unlocked, false otherwise.
+ * \see lock
+ */
+ bool release_lock()
+ {
+ return (SDL_UnlockMutex(mutex_) == 0);
+ }
+
+
+ /**
+ * As an alternative method for locking, objects of this class will
+ * automagically release the lock if it is still locked at
+ * deconstruction. Therefore, it's generally safer to use this method
+ * since it makes it much more difficult to forget to unlock a mutex.
+ */
+ class lock
+ {
+ public:
+
+ /**
+ * Construct a lock.
+ * \param mutex The mutex.
+ */
+ explicit lock(mutex& mutex) :
+ mutex_(mutex),
+ is_locked_(false) {}
+
+ /**
+ * Deconstruct a lock. The lock is automagically released if it is
+ * still locked.
+ */
+ ~lock()
+ {
+ if (is_locked_) release();
+ }
+
+
+ /**
+ * Try to acquire a lock on the mutex.
+ * \return True if the mutex was locked, false otherwise.
+ */
+ bool acquire()
+ {
+ return (is_locked_ = mutex_.acquire_lock());
+ }
+
+ /**
+ * Release the lock.
+ * \return True if the mutex was unlocked, false otherwise.
+ */
+ bool release()
+ {
+ bool result = mutex_.release_lock();
+ is_locked_ = false;
+ return result;
+ }
+
+
+ /**
+ * Get whether or not the mutex is locked.
+ * \return True if the mutex is locked, false otherwise.
+ */
+ bool is_locked() const
+ {
+ return is_locked_;
+ }
+
+
+ protected:
+
+ mutex& mutex_;
+ bool is_locked_;
+
+ friend class condition;
+ };
+
+ /**
+ * This type of lock tries to acquire a lock on the mutex during
+ * construction and releases the lock on deconstruction.
+ */
+ class scoped_lock : private lock
+ {
+ public:
+
+ /**
+ * Construct a lock.
+ * \param mutex The mutex.
+ */
+ explicit scoped_lock(mutex& mutex) :
+ lock(mutex)
+ {
+ acquire();
+ }
+
+ /**
+ * Get whether or not the mutex is locked.
+ * \return True if the mutex is locked, false otherwise.
+ */
+ bool is_locked() const
+ {
+ return lock::is_locked();
+ }
+ };
+
+
+private:
+
+ SDL_mutex* mutex_;
+
+ friend class condition;
+};
+
+
+/**
+ * A class representing a condition variable.
+ */
+class condition
+{
+public:
+
+ /**
+ * Construct a condition.
+ */
+ condition()
+ {
+ condition_ = SDL_CreateCond();
+ }
+
+ /**
+ * Deconstruct a condition.
+ */
+ ~condition()
+ {
+ SDL_DestroyCond(condition_);
+ }
+
+
+ /**
+ * Unlock the mutex and wait for another thread to notify the thread,
+ * at which point the mutex will be re-locked and the method will
+ * return.
+ * \param mutex The mutex.
+ * \return True if the thread was notified, false otherwise.
+ */
+ bool wait(mutex& mutex)
+ {
+ return (SDL_CondWait(condition_, mutex.mutex_) == 0);
+ }
+
+ /**
+ * Unlock the mutex associated with a lock and wait for another thread
+ * to notify the thread, at which point the lock will be re-locked and
+ * the method will return.
+ * \param lock The lock.
+ * \return True if the thread was notified, false otherwise.
+ */
+ bool wait(mutex::lock& lock)
+ {
+ return (SDL_CondWait(condition_, lock.mutex_.mutex_) == 0);
+ }
+
+ /**
+ * Unlock the mutex and wait for another thread to notify the thread,
+ * at which point the mutex will be re-locked and the method will
+ * return. If the thread was not notified before a certain number of
+ * seconds, the method will return anyway.
+ * \param mutex The mutex.
+ * \param timeout Number of seconds to wait.
+ * \return True if the thread was notified, false otherwise.
+ */
+ bool wait(mutex& mutex, scalar timeout)
+ {
+ Uint32 ms = timeout * SCALAR(1000.0);
+ return (SDL_CondWaitTimeout(condition_, mutex.mutex_, ms) == 0);
+ }
+
+ /**
+ * Unlock the mutex associated with a lock and wait for another thread
+ * to notify the thread, at which point the lock will be re-locked and
+ * the method will return. If the thread was not notified before a
+ * certain number of seconds, the method will return anyway.
+ * \param lock The lock.
+ * \param timeout Number of seconds to wait.
+ * \return True if the thread was notified, false otherwise.
+ */
+ bool wait(mutex::lock& lock, scalar timeout)
+ {
+ Uint32 ms = timeout * SCALAR(1000.0);
+ return (SDL_CondWaitTimeout(condition_,
+ lock.mutex_.mutex_, ms) == 0);
+ }
+
+
+ /**
+ * Notify one other thread that is waiting on the condition.
+ * \return True on success, false otherwise.
+ */
+ bool notify()
+ {
+ return (SDL_CondSignal(condition_) == 0);
+ }
+
+ /**
+ * Notify all other threads that are waiting on the condition.
+ * \return True on success, false otherwise.
+ */
+ bool notify_all()
+ {
+ return (SDL_CondBroadcast(condition_) == 0);
+ }
+
+
+private:
+
+ SDL_cond* condition_;
+};
+
+
+/**
+ * A semaphore class.
+ */
+class semaphore
+{
+public:
+
+ /**
+ * Construct a semaphore.
+ * \param value The initial value of the semaphore.
+ */
+ explicit semaphore(uint32_t value)
+ {
+ semaphore_ = SDL_CreateSemaphore(value);
+ }
+
+ /**
+ * Deconstruct a semaphore.
+ */
+ ~semaphore()
+ {
+ SDL_DestroySemaphore(semaphore_);
+ }
+
+
+ /**
+ * Block until the calling thread can secure exclusive access to the
+ * code protected by the semaphore.
+ * \return True if the lock was acquired, false otherwise.
+ * \see lock
+ */
+ bool acquire_lock()
+ {
+ return (SDL_SemWait(semaphore_) == 0);
+ }
+
+ /**
+ * Block until the calling thread can secure exclusive access to the
+ * code protected by the semaphore, or until the timeout expires.
+ * \param timeout Number of seconds to try.
+ * \return True if the lock was acquired, false otherwise.
+ */
+ bool acquire_lock(scalar timeout)
+ {
+ Uint32 ms = timeout * SCALAR(1000.0);
+ return (SDL_SemWaitTimeout(semaphore_, ms) == 0);
+ }
+
+ /**
+ * Unlock the semaphore. Call this after the sensitive block of code
+ * to allow another thread to acquire the lock.
+ * \return True if the semaphore was unlocked, false otherwise.
+ * \see lock
+ */
+ bool release_lock()
+ {
+ return (SDL_SemPost(semaphore_) == 0);
+ }
+
+ /**
+ * Try to lock the semaphore, but don't block if the lock is not
+ * immediately available.
+ * \return True if the semaphore was locked, false otherwise.
+ */
+ bool try_lock()
+ {
+ return (SDL_SemTryWait(semaphore_) == 0);
+ }
+
+ /**
+ * As an alternative method for locking, objects of this class will
+ * automagically release the lock if it is still locked at
+ * deconstruction. Therefore, it's generally safer to use this method
+ * since it makes it much more difficult to forget to unlock a
+ * semaphore.
+ */
+ class lock
+ {
+ public:
+
+ /**
+ * Construct a lock.
+ * \param semaphore The semaphore.
+ */
+ explicit lock(semaphore& semaphore) :
+ semaphore_(semaphore),
+ is_locked_(false) {}
+
+ /**
+ * Deconstruct a lock. The lock is automagically released if it is
+ * still locked.
+ */
+ ~lock()
+ {
+ if (is_locked_) release();
+ }
+
+
+ /**
+ * Try to acquire a lock on the semaphore.
+ * \return True if the semaphore was locked, false otherwise.
+ */
+ bool acquire()
+ {
+ return (is_locked_ = semaphore_.acquire_lock());
+ }
+
+ /**
+ * Release the lock.
+ * \return True if the semaphore was unlocked, false otherwise.
+ */
+ bool release()
+ {
+ bool result = semaphore_.release_lock();
+ is_locked_ = false;
+ return result;
+ }
+
+ /**
+ * Get whether or not the semaphore is locked.
+ * \return True if the semaphore is locked, false otherwise.
+ */
+ bool is_locked() const
+ {
+ return is_locked_;
+ }
+
+
+ protected:
+
+ semaphore& semaphore_;
+ bool is_locked_;
+ };
+
+ /**
+ * This type of lock tries to acquire a lock on the semaphore during
+ * construction and releases the lock on deconstruction.
+ */
+ class scoped_lock : private lock
+ {
+ public:
+
+ /**
+ * Construct a lock.
+ * \param semaphore The semaphore.
+ */
+ explicit scoped_lock(semaphore& semaphore) :
+ lock(semaphore)
+ {
+ acquire();
+ }
+
+ /**
+ * Get whether or not the semaphore is locked.
+ * \return True if the semaphore is locked, false otherwise.
+ */
+ bool is_locked() const
+ {
+ return lock::is_locked();
+ }
+ };
+
+
+private:
+
+ SDL_sem* semaphore_;
+};
+
+
+} // namespace moof
+
+#endif // _MOOF_THREAD_HH_
+
projects / chaz / yoink / blobdiff