diff options
Diffstat (limited to 'thread_sync.c')
| -rw-r--r-- | thread_sync.c | 1532 |
1 files changed, 1532 insertions, 0 deletions
diff --git a/thread_sync.c b/thread_sync.c new file mode 100644 index 0000000000..f775d44451 --- /dev/null +++ b/thread_sync.c @@ -0,0 +1,1532 @@ +/* included by thread.c */ +#include "ccan/list/list.h" + +static VALUE rb_cMutex, rb_cQueue, rb_cSizedQueue, rb_cConditionVariable; +static VALUE rb_eClosedQueueError; + +/* + * keep these globally so we can walk and reinitialize them at fork + * in the child process + */ +static LIST_HEAD(szqueue_list); +static LIST_HEAD(queue_list); +static LIST_HEAD(condvar_list); + +/* sync_waiter is always on-stack */ +struct sync_waiter { + rb_thread_t *th; + struct list_node node; +}; + +#define MUTEX_ALLOW_TRAP FL_USER1 + +static int +wakeup_one(struct list_head *head) +{ + struct sync_waiter *cur = 0, *next = 0; + + list_for_each_safe(head, cur, next, node) { + list_del_init(&cur->node); + if (cur->th->status != THREAD_KILLED) { + rb_threadptr_interrupt(cur->th); + cur->th->status = THREAD_RUNNABLE; + return TRUE; + } + } + return FALSE; +} + +static void +wakeup_all(struct list_head *head) +{ + struct sync_waiter *cur = 0, *next = 0; + + list_for_each_safe(head, cur, next, node) { + list_del_init(&cur->node); + if (cur->th->status != THREAD_KILLED) { + rb_threadptr_interrupt(cur->th); + cur->th->status = THREAD_RUNNABLE; + } + } +} + +/* Mutex */ + +typedef struct rb_mutex_struct { + struct rb_thread_struct volatile *th; + struct rb_mutex_struct *next_mutex; + struct list_head waitq; /* protected by GVL */ +} rb_mutex_t; + +#if defined(HAVE_WORKING_FORK) +static void rb_mutex_abandon_all(rb_mutex_t *mutexes); +static void rb_mutex_abandon_keeping_mutexes(rb_thread_t *th); +static void rb_mutex_abandon_locking_mutex(rb_thread_t *th); +#endif +static const char* rb_mutex_unlock_th(rb_mutex_t *mutex, rb_thread_t volatile *th); + +/* + * Document-class: Mutex + * + * Mutex implements a simple semaphore that can be used to coordinate access to + * shared data from multiple concurrent threads. + * + * Example: + * + * semaphore = Mutex.new + * + * a = Thread.new { + * semaphore.synchronize { + * # access shared resource + * } + * } + * + * b = Thread.new { + * semaphore.synchronize { + * # access shared resource + * } + * } + * + */ + +#define GetMutexPtr(obj, tobj) \ + TypedData_Get_Struct((obj), rb_mutex_t, &mutex_data_type, (tobj)) + +#define mutex_mark NULL + +static size_t +rb_mutex_num_waiting(rb_mutex_t *mutex) +{ + struct sync_waiter *w = 0; + size_t n = 0; + + list_for_each(&mutex->waitq, w, node) { + n++; + } + + return n; +} + +static void +mutex_free(void *ptr) +{ + rb_mutex_t *mutex = ptr; + if (mutex->th) { + /* rb_warn("free locked mutex"); */ + const char *err = rb_mutex_unlock_th(mutex, mutex->th); + if (err) rb_bug("%s", err); + } + ruby_xfree(ptr); +} + +static size_t +mutex_memsize(const void *ptr) +{ + return sizeof(rb_mutex_t); +} + +static const rb_data_type_t mutex_data_type = { + "mutex", + {mutex_mark, mutex_free, mutex_memsize,}, + 0, 0, RUBY_TYPED_FREE_IMMEDIATELY +}; + +VALUE +rb_obj_is_mutex(VALUE obj) +{ + if (rb_typeddata_is_kind_of(obj, &mutex_data_type)) { + return Qtrue; + } + else { + return Qfalse; + } +} + +static VALUE +mutex_alloc(VALUE klass) +{ + VALUE obj; + rb_mutex_t *mutex; + + obj = TypedData_Make_Struct(klass, rb_mutex_t, &mutex_data_type, mutex); + list_head_init(&mutex->waitq); + return obj; +} + +/* + * call-seq: + * Mutex.new -> mutex + * + * Creates a new Mutex + */ +static VALUE +mutex_initialize(VALUE self) +{ + return self; +} + +VALUE +rb_mutex_new(void) +{ + return mutex_alloc(rb_cMutex); +} + +/* + * call-seq: + * mutex.locked? -> true or false + * + * Returns +true+ if this lock is currently held by some thread. + */ +VALUE +rb_mutex_locked_p(VALUE self) +{ + rb_mutex_t *mutex; + GetMutexPtr(self, mutex); + return mutex->th ? Qtrue : Qfalse; +} + +static void +mutex_locked(rb_thread_t *th, VALUE self) +{ + rb_mutex_t *mutex; + GetMutexPtr(self, mutex); + + if (th->keeping_mutexes) { + mutex->next_mutex = th->keeping_mutexes; + } + th->keeping_mutexes = mutex; +} + +/* + * call-seq: + * mutex.try_lock -> true or false + * + * Attempts to obtain the lock and returns immediately. Returns +true+ if the + * lock was granted. + */ +VALUE +rb_mutex_trylock(VALUE self) +{ + rb_mutex_t *mutex; + VALUE locked = Qfalse; + GetMutexPtr(self, mutex); + + if (mutex->th == 0) { + rb_thread_t *th = GET_THREAD(); + mutex->th = th; + locked = Qtrue; + + mutex_locked(th, self); + } + + return locked; +} + +/* + * At maximum, only one thread can use cond_timedwait and watch deadlock + * periodically. Multiple polling thread (i.e. concurrent deadlock check) + * introduces new race conditions. [Bug #6278] [ruby-core:44275] + */ +static const rb_thread_t *patrol_thread = NULL; + +static VALUE +do_mutex_lock(VALUE self, int interruptible_p) +{ + rb_thread_t *th = GET_THREAD(); + rb_mutex_t *mutex; + GetMutexPtr(self, mutex); + + /* When running trap handler */ + if (!FL_TEST_RAW(self, MUTEX_ALLOW_TRAP) && + th->ec->interrupt_mask & TRAP_INTERRUPT_MASK) { + rb_raise(rb_eThreadError, "can't be called from trap context"); + } + + if (rb_mutex_trylock(self) == Qfalse) { + struct sync_waiter w; + + if (mutex->th == th) { + rb_raise(rb_eThreadError, "deadlock; recursive locking"); + } + + w.th = th; + + while (mutex->th != th) { + enum rb_thread_status prev_status = th->status; + struct timeval *timeout = 0; + struct timeval tv = { 0, 100000 }; /* 100ms */ + + th->status = THREAD_STOPPED_FOREVER; + th->locking_mutex = self; + th->vm->sleeper++; + /* + * Carefully! while some contended threads are in native_sleep(), + * vm->sleeper is unstable value. we have to avoid both deadlock + * and busy loop. + */ + if ((vm_living_thread_num(th->vm) == th->vm->sleeper) && + !patrol_thread) { + timeout = &tv; + patrol_thread = th; + } + + list_add_tail(&mutex->waitq, &w.node); + native_sleep(th, timeout); /* release GVL */ + list_del(&w.node); + + if (!mutex->th) { + mutex->th = th; + } + + if (patrol_thread == th) + patrol_thread = NULL; + + th->locking_mutex = Qfalse; + if (mutex->th && timeout && !RUBY_VM_INTERRUPTED(th->ec)) { + rb_check_deadlock(th->vm); + } + if (th->status == THREAD_STOPPED_FOREVER) { + th->status = prev_status; + } + th->vm->sleeper--; + + if (interruptible_p) { + /* release mutex before checking for interrupts...as interrupt checking + * code might call rb_raise() */ + if (mutex->th == th) mutex->th = 0; + RUBY_VM_CHECK_INTS_BLOCKING(th->ec); /* may release mutex */ + if (!mutex->th) { + mutex->th = th; + mutex_locked(th, self); + } + } else { + if (mutex->th == th) mutex_locked(th, self); + } + } + } + return self; +} + +static VALUE +mutex_lock_uninterruptible(VALUE self) +{ + return do_mutex_lock(self, 0); +} + +/* + * call-seq: + * mutex.lock -> self + * + * Attempts to grab the lock and waits if it isn't available. + * Raises +ThreadError+ if +mutex+ was locked by the current thread. + */ +VALUE +rb_mutex_lock(VALUE self) +{ + return do_mutex_lock(self, 1); +} + +/* + * call-seq: + * mutex.owned? -> true or false + * + * Returns +true+ if this lock is currently held by current thread. + */ +VALUE +rb_mutex_owned_p(VALUE self) +{ + VALUE owned = Qfalse; + rb_thread_t *th = GET_THREAD(); + rb_mutex_t *mutex; + + GetMutexPtr(self, mutex); + + if (mutex->th == th) + owned = Qtrue; + + return owned; +} + +static const char * +rb_mutex_unlock_th(rb_mutex_t *mutex, rb_thread_t volatile *th) +{ + const char *err = NULL; + + if (mutex->th == 0) { + err = "Attempt to unlock a mutex which is not locked"; + } + else if (mutex->th != th) { + err = "Attempt to unlock a mutex which is locked by another thread"; + } + else { + struct sync_waiter *cur = 0, *next = 0; + rb_mutex_t *volatile *th_mutex = &th->keeping_mutexes; + + mutex->th = 0; + list_for_each_safe(&mutex->waitq, cur, next, node) { + list_del_init(&cur->node); + switch (cur->th->status) { + case THREAD_RUNNABLE: /* from someone else calling Thread#run */ + case THREAD_STOPPED_FOREVER: /* likely (rb_mutex_lock) */ + rb_threadptr_interrupt(cur->th); + goto found; + case THREAD_STOPPED: /* probably impossible */ + rb_bug("unexpected THREAD_STOPPED"); + case THREAD_KILLED: + /* not sure about this, possible in exit GC? */ + rb_bug("unexpected THREAD_KILLED"); + continue; + } + } + found: + while (*th_mutex != mutex) { + th_mutex = &(*th_mutex)->next_mutex; + } + *th_mutex = mutex->next_mutex; + mutex->next_mutex = NULL; + } + + return err; +} + +/* + * call-seq: + * mutex.unlock -> self + * + * Releases the lock. + * Raises +ThreadError+ if +mutex+ wasn't locked by the current thread. + */ +VALUE +rb_mutex_unlock(VALUE self) +{ + const char *err; + rb_mutex_t *mutex; + GetMutexPtr(self, mutex); + + err = rb_mutex_unlock_th(mutex, GET_THREAD()); + if (err) rb_raise(rb_eThreadError, "%s", err); + + return self; +} + +#if defined(HAVE_WORKING_FORK) +static void +rb_mutex_abandon_keeping_mutexes(rb_thread_t *th) +{ + if (th->keeping_mutexes) { + rb_mutex_abandon_all(th->keeping_mutexes); + } + th->keeping_mutexes = NULL; +} + +static void +rb_mutex_abandon_locking_mutex(rb_thread_t *th) +{ + rb_mutex_t *mutex; + + if (!th->locking_mutex) return; + + GetMutexPtr(th->locking_mutex, mutex); + if (mutex->th == th) + rb_mutex_abandon_all(mutex); + th->locking_mutex = Qfalse; +} + +static void +rb_mutex_abandon_all(rb_mutex_t *mutexes) +{ + rb_mutex_t *mutex; + + while (mutexes) { + mutex = mutexes; + mutexes = mutex->next_mutex; + mutex->th = 0; + mutex->next_mutex = 0; + list_head_init(&mutex->waitq); + } +} + +/* + * All other threads are dead in the a new child process, so waitqs + * contain references to dead threads which we need to clean up + */ +static void +rb_mutex_cleanup_keeping_mutexes(const rb_thread_t *current_thread) +{ + rb_mutex_t *mutex = current_thread->keeping_mutexes; + while (mutex) { + list_head_init(&mutex->waitq); + mutex = mutex->next_mutex; + } +} +#endif + +static VALUE +rb_mutex_sleep_forever(VALUE time) +{ + rb_thread_sleep_deadly_allow_spurious_wakeup(); + return Qnil; +} + +static VALUE +rb_mutex_wait_for(VALUE time) +{ + struct timeval *t = (struct timeval *)time; + sleep_timeval(GET_THREAD(), *t, 0); /* permit spurious check */ + return Qnil; +} + +VALUE +rb_mutex_sleep(VALUE self, VALUE timeout) +{ + time_t beg, end; + struct timeval t; + + if (!NIL_P(timeout)) { + t = rb_time_interval(timeout); + } + rb_mutex_unlock(self); + beg = time(0); + if (NIL_P(timeout)) { + rb_ensure(rb_mutex_sleep_forever, Qnil, mutex_lock_uninterruptible, self); + } + else { + rb_ensure(rb_mutex_wait_for, (VALUE)&t, mutex_lock_uninterruptible, self); + } + RUBY_VM_CHECK_INTS_BLOCKING(GET_EC()); + end = time(0) - beg; + return INT2FIX(end); +} + +/* + * call-seq: + * mutex.sleep(timeout = nil) -> number + * + * Releases the lock and sleeps +timeout+ seconds if it is given and + * non-nil or forever. Raises +ThreadError+ if +mutex+ wasn't locked by + * the current thread. + * + * When the thread is next woken up, it will attempt to reacquire + * the lock. + * + * Note that this method can wakeup without explicit Thread#wakeup call. + * For example, receiving signal and so on. + */ +static VALUE +mutex_sleep(int argc, VALUE *argv, VALUE self) +{ + VALUE timeout; + + rb_scan_args(argc, argv, "01", &timeout); + return rb_mutex_sleep(self, timeout); +} + +/* + * call-seq: + * mutex.synchronize { ... } -> result of the block + * + * Obtains a lock, runs the block, and releases the lock when the block + * completes. See the example under +Mutex+. + */ + +VALUE +rb_mutex_synchronize(VALUE mutex, VALUE (*func)(VALUE arg), VALUE arg) +{ + rb_mutex_lock(mutex); + return rb_ensure(func, arg, rb_mutex_unlock, mutex); +} + +/* + * call-seq: + * mutex.synchronize { ... } -> result of the block + * + * Obtains a lock, runs the block, and releases the lock when the block + * completes. See the example under +Mutex+. + */ +static VALUE +rb_mutex_synchronize_m(VALUE self, VALUE args) +{ + if (!rb_block_given_p()) { + rb_raise(rb_eThreadError, "must be called with a block"); + } + + return rb_mutex_synchronize(self, rb_yield, Qundef); +} + +void rb_mutex_allow_trap(VALUE self, int val) +{ + Check_TypedStruct(self, &mutex_data_type); + + if (val) + FL_SET_RAW(self, MUTEX_ALLOW_TRAP); + else + FL_UNSET_RAW(self, MUTEX_ALLOW_TRAP); +} + +/* Queue */ + +#define queue_waitq(q) UNALIGNED_MEMBER_PTR(q, waitq) +PACKED_STRUCT_UNALIGNED(struct rb_queue { + struct list_head waitq; + rb_serial_t fork_gen; + const VALUE que; + int num_waiting; +}); + +#define szqueue_waitq(sq) UNALIGNED_MEMBER_PTR(sq, q.waitq) +#define szqueue_pushq(sq) UNALIGNED_MEMBER_PTR(sq, pushq) +PACKED_STRUCT_UNALIGNED(struct rb_szqueue { + struct rb_queue q; + int num_waiting_push; + struct list_head pushq; + long max; +}); + +static void +queue_mark(void *ptr) +{ + struct rb_queue *q = ptr; + + /* no need to mark threads in waitq, they are on stack */ + rb_gc_mark(q->que); +} + +static size_t +queue_memsize(const void *ptr) +{ + return sizeof(struct rb_queue); +} + +static const rb_data_type_t queue_data_type = { + "queue", + {queue_mark, RUBY_TYPED_DEFAULT_FREE, queue_memsize,}, + 0, 0, RUBY_TYPED_FREE_IMMEDIATELY|RUBY_TYPED_WB_PROTECTED +}; + +static VALUE +queue_alloc(VALUE klass) +{ + VALUE obj; + struct rb_queue *q; + + obj = TypedData_Make_Struct(klass, struct rb_queue, &queue_data_type, q); + list_head_init(queue_waitq(q)); + return obj; +} + +static int +queue_fork_check(struct rb_queue *q) +{ + rb_serial_t fork_gen = GET_VM()->fork_gen; + + if (q->fork_gen == fork_gen) { + return 0; + } + /* forked children can't reach into parent thread stacks */ + q->fork_gen = fork_gen; + list_head_init(queue_waitq(q)); + q->num_waiting = 0; + return 1; +} + +static struct rb_queue * +queue_ptr(VALUE obj) +{ + struct rb_queue *q; + + TypedData_Get_Struct(obj, struct rb_queue, &queue_data_type, q); + queue_fork_check(q); + + return q; +} + +#define QUEUE_CLOSED FL_USER5 + +static void +szqueue_mark(void *ptr) +{ + struct rb_szqueue *sq = ptr; + + queue_mark(&sq->q); +} + +static size_t +szqueue_memsize(const void *ptr) +{ + return sizeof(struct rb_szqueue); +} + +static const rb_data_type_t szqueue_data_type = { + "sized_queue", + {szqueue_mark, RUBY_TYPED_DEFAULT_FREE, szqueue_memsize,}, + 0, 0, RUBY_TYPED_FREE_IMMEDIATELY|RUBY_TYPED_WB_PROTECTED +}; + +static VALUE +szqueue_alloc(VALUE klass) +{ + struct rb_szqueue *sq; + VALUE obj = TypedData_Make_Struct(klass, struct rb_szqueue, + &szqueue_data_type, sq); + list_head_init(szqueue_waitq(sq)); + list_head_init(szqueue_pushq(sq)); + return obj; +} + +static struct rb_szqueue * +szqueue_ptr(VALUE obj) +{ + struct rb_szqueue *sq; + + TypedData_Get_Struct(obj, struct rb_szqueue, &szqueue_data_type, sq); + if (queue_fork_check(&sq->q)) { + list_head_init(szqueue_pushq(sq)); + sq->num_waiting_push = 0; + } + + return sq; +} + +static VALUE +ary_buf_new(void) +{ + return rb_ary_tmp_new(1); +} + +static VALUE +check_array(VALUE obj, VALUE ary) +{ + if (!RB_TYPE_P(ary, T_ARRAY)) { + rb_raise(rb_eTypeError, "%+"PRIsVALUE" not initialized", obj); + } + return ary; +} + +static long +queue_length(VALUE self, struct rb_queue *q) +{ + return RARRAY_LEN(check_array(self, q->que)); +} + +static int +queue_closed_p(VALUE self) +{ + return FL_TEST_RAW(self, QUEUE_CLOSED) != 0; +} + +static void +raise_closed_queue_error(VALUE self) +{ + rb_raise(rb_eClosedQueueError, "queue closed"); +} + +static VALUE +queue_closed_result(VALUE self, struct rb_queue *q) +{ + assert(queue_length(self, q) == 0); + return Qnil; +} + +/* + * Document-class: Queue + * + * The Queue class implements multi-producer, multi-consumer queues. + * It is especially useful in threaded programming when information + * must be exchanged safely between multiple threads. The Queue class + * implements all the required locking semantics. + * + * The class implements FIFO type of queue. In a FIFO queue, the first + * tasks added are the first retrieved. + * + * Example: + * + * queue = Queue.new + * + * producer = Thread.new do + * 5.times do |i| + * sleep rand(i) # simulate expense + * queue << i + * puts "#{i} produced" + * end + * end + * + * consumer = Thread.new do + * 5.times do |i| + * value = queue.pop + * sleep rand(i/2) # simulate expense + * puts "consumed #{value}" + * end + * end + * + */ + +/* + * Document-method: Queue::new + * + * Creates a new queue instance. + */ + +static VALUE +rb_queue_initialize(VALUE self) +{ + struct rb_queue *q = queue_ptr(self); + RB_OBJ_WRITE(self, &q->que, ary_buf_new()); + list_head_init(queue_waitq(q)); + return self; +} + +static VALUE +queue_do_push(VALUE self, struct rb_queue *q, VALUE obj) +{ + if (queue_closed_p(self)) { + raise_closed_queue_error(self); + } + rb_ary_push(check_array(self, q->que), obj); + wakeup_one(queue_waitq(q)); + return self; +} + +/* + * Document-method: Queue#close + * call-seq: + * close + * + * Closes the queue. A closed queue cannot be re-opened. + * + * After the call to close completes, the following are true: + * + * - +closed?+ will return true + * + * - +close+ will be ignored. + * + * - calling enq/push/<< will raise an exception. + * + * - when +empty?+ is false, calling deq/pop/shift will return an object + * from the queue as usual. + * + * ClosedQueueError is inherited from StopIteration, so that you can break loop block. + * + * Example: + * + * q = Queue.new + * Thread.new{ + * while e = q.deq # wait for nil to break loop + * # ... + * end + * } + * q.close + */ + +static VALUE +rb_queue_close(VALUE self) +{ + struct rb_queue *q = queue_ptr(self); + + if (!queue_closed_p(self)) { + FL_SET(self, QUEUE_CLOSED); + + wakeup_all(queue_waitq(q)); + } + + return self; +} + +/* + * Document-method: Queue#closed? + * call-seq: closed? + * + * Returns +true+ if the queue is closed. + */ + +static VALUE +rb_queue_closed_p(VALUE self) +{ + return queue_closed_p(self) ? Qtrue : Qfalse; +} + +/* + * Document-method: Queue#push + * call-seq: + * push(object) + * enq(object) + * <<(object) + * + * Pushes the given +object+ to the queue. + */ + +static VALUE +rb_queue_push(VALUE self, VALUE obj) +{ + return queue_do_push(self, queue_ptr(self), obj); +} + +static VALUE +queue_sleep(VALUE arg) +{ + rb_thread_sleep_deadly_allow_spurious_wakeup(); + return Qnil; +} + +struct queue_waiter { + struct sync_waiter w; + union { + struct rb_queue *q; + struct rb_szqueue *sq; + } as; +}; + +static VALUE +queue_sleep_done(VALUE p) +{ + struct queue_waiter *qw = (struct queue_waiter *)p; + + list_del(&qw->w.node); + qw->as.q->num_waiting--; + + return Qfalse; +} + +static VALUE +szqueue_sleep_done(VALUE p) +{ + struct queue_waiter *qw = (struct queue_waiter *)p; + + list_del(&qw->w.node); + qw->as.sq->num_waiting_push--; + + return Qfalse; +} + +static VALUE +queue_do_pop(VALUE self, struct rb_queue *q, int should_block) +{ + check_array(self, q->que); + + while (RARRAY_LEN(q->que) == 0) { + if (!should_block) { + rb_raise(rb_eThreadError, "queue empty"); + } + else if (queue_closed_p(self)) { + return queue_closed_result(self, q); + } + else { + struct queue_waiter qw; + + assert(RARRAY_LEN(q->que) == 0); + assert(queue_closed_p(self) == 0); + + qw.w.th = GET_THREAD(); + qw.as.q = q; + list_add_tail(&qw.as.q->waitq, &qw.w.node); + qw.as.q->num_waiting++; + + rb_ensure(queue_sleep, self, queue_sleep_done, (VALUE)&qw); + } + } + + return rb_ary_shift(q->que); +} + +static int +queue_pop_should_block(int argc, const VALUE *argv) +{ + int should_block = 1; + rb_check_arity(argc, 0, 1); + if (argc > 0) { + should_block = !RTEST(argv[0]); + } + return should_block; +} + +/* + * Document-method: Queue#pop + * call-seq: + * pop(non_block=false) + * deq(non_block=false) + * shift(non_block=false) + * + * Retrieves data from the queue. + * + * If the queue is empty, the calling thread is suspended until data is pushed + * onto the queue. If +non_block+ is true, the thread isn't suspended, and + * +ThreadError+ is raised. + */ + +static VALUE +rb_queue_pop(int argc, VALUE *argv, VALUE self) +{ + int should_block = queue_pop_should_block(argc, argv); + return queue_do_pop(self, queue_ptr(self), should_block); +} + +/* + * Document-method: Queue#empty? + * call-seq: empty? + * + * Returns +true+ if the queue is empty. + */ + +static VALUE +rb_queue_empty_p(VALUE self) +{ + return queue_length(self, queue_ptr(self)) == 0 ? Qtrue : Qfalse; +} + +/* + * Document-method: Queue#clear + * + * Removes all objects from the queue. + */ + +static VALUE +rb_queue_clear(VALUE self) +{ + struct rb_queue *q = queue_ptr(self); + + rb_ary_clear(check_array(self, q->que)); + return self; +} + +/* + * Document-method: Queue#length + * call-seq: + * length + * size + * + * Returns the length of the queue. + */ + +static VALUE +rb_queue_length(VALUE self) +{ + return LONG2NUM(queue_length(self, queue_ptr(self))); +} + +/* + * Document-method: Queue#num_waiting + * + * Returns the number of threads waiting on the queue. + */ + +static VALUE +rb_queue_num_waiting(VALUE self) +{ + struct rb_queue *q = queue_ptr(self); + + return INT2NUM(q->num_waiting); +} + +/* + * Document-class: SizedQueue + * + * This class represents queues of specified size capacity. The push operation + * may be blocked if the capacity is full. + * + * See Queue for an example of how a SizedQueue works. + */ + +/* + * Document-method: SizedQueue::new + * call-seq: new(max) + * + * Creates a fixed-length queue with a maximum size of +max+. + */ + +static VALUE +rb_szqueue_initialize(VALUE self, VALUE vmax) +{ + long max; + struct rb_szqueue *sq = szqueue_ptr(self); + + max = NUM2LONG(vmax); + if (max <= 0) { + rb_raise(rb_eArgError, "queue size must be positive"); + } + + RB_OBJ_WRITE(self, &sq->q.que, ary_buf_new()); + list_head_init(szqueue_waitq(sq)); + list_head_init(szqueue_pushq(sq)); + sq->max = max; + + return self; +} + +/* + * Document-method: SizedQueue#close + * call-seq: + * close + * + * Similar to Queue#close. + * + * The difference is behavior with waiting enqueuing threads. + * + * If there are waiting enqueuing threads, they are interrupted by + * raising ClosedQueueError('queue closed'). + */ +static VALUE +rb_szqueue_close(VALUE self) +{ + if (!queue_closed_p(self)) { + struct rb_szqueue *sq = szqueue_ptr(self); + + FL_SET(self, QUEUE_CLOSED); + wakeup_all(szqueue_waitq(sq)); + wakeup_all(szqueue_pushq(sq)); + } + return self; +} + +/* + * Document-method: SizedQueue#max + * + * Returns the maximum size of the queue. + */ + +static VALUE +rb_szqueue_max_get(VALUE self) +{ + return LONG2NUM(szqueue_ptr(self)->max); +} + +/* + * Document-method: SizedQueue#max= + * call-seq: max=(number) + * + * Sets the maximum size of the queue to the given +number+. + */ + +static VALUE +rb_szqueue_max_set(VALUE self, VALUE vmax) +{ + long max = NUM2LONG(vmax); + long diff = 0; + struct rb_szqueue *sq = szqueue_ptr(self); + + if (max <= 0) { + rb_raise(rb_eArgError, "queue size must be positive"); + } + if (max > sq->max) { + diff = max - sq->max; + } + sq->max = max; + while (diff-- > 0 && wakeup_one(szqueue_pushq(sq))) { + /* keep waking more up */ + } + return vmax; +} + +static int +szqueue_push_should_block(int argc, const VALUE *argv) +{ + int should_block = 1; + rb_check_arity(argc, 1, 2); + if (argc > 1) { + should_block = !RTEST(argv[1]); + } + return should_block; +} + +/* + * Document-method: SizedQueue#push + * call-seq: + * push(object, non_block=false) + * enq(object, non_block=false) + * <<(object) + * + * Pushes +object+ to the queue. + * + * If there is no space left in the queue, waits until space becomes + * available, unless +non_block+ is true. If +non_block+ is true, the + * thread isn't suspended, and +ThreadError+ is raised. + */ + +static VALUE +rb_szqueue_push(int argc, VALUE *argv, VALUE self) +{ + struct rb_szqueue *sq = szqueue_ptr(self); + int should_block = szqueue_push_should_block(argc, argv); + + while (queue_length(self, &sq->q) >= sq->max) { + if (!should_block) { + rb_raise(rb_eThreadError, "queue full"); + } + else if (queue_closed_p(self)) { + goto closed; + } + else { + struct queue_waiter qw; + struct list_head *pushq = szqueue_pushq(sq); + + qw.w.th = GET_THREAD(); + qw.as.sq = sq; + list_add_tail(pushq, &qw.w.node); + sq->num_waiting_push++; + + rb_ensure(queue_sleep, self, szqueue_sleep_done, (VALUE)&qw); + } + } + + if (queue_closed_p(self)) { + closed: + raise_closed_queue_error(self); + } + + return queue_do_push(self, &sq->q, argv[0]); +} + +static VALUE +szqueue_do_pop(VALUE self, int should_block) +{ + struct rb_szqueue *sq = szqueue_ptr(self); + VALUE retval = queue_do_pop(self, &sq->q, should_block); + + if (queue_length(self, &sq->q) < sq->max) { + wakeup_one(szqueue_pushq(sq)); + } + + return retval; +} + +/* + * Document-method: SizedQueue#pop + * call-seq: + * pop(non_block=false) + * deq(non_block=false) + * shift(non_block=false) + * + * Retrieves data from the queue. + * + * If the queue is empty, the calling thread is suspended until data is pushed + * onto the queue. If +non_block+ is true, the thread isn't suspended, and + * +ThreadError+ is raised. + */ + +static VALUE +rb_szqueue_pop(int argc, VALUE *argv, VALUE self) +{ + int should_block = queue_pop_should_block(argc, argv); + return szqueue_do_pop(self, should_block); +} + +/* + * Document-method: SizedQueue#clear + * + * Removes all objects from the queue. + */ + +static VALUE +rb_szqueue_clear(VALUE self) +{ + struct rb_szqueue *sq = szqueue_ptr(self); + + rb_ary_clear(check_array(self, sq->q.que)); + wakeup_all(szqueue_pushq(sq)); + return self; +} + +static VALUE +rb_szqueue_length(VALUE self) +{ + struct rb_szqueue *sq = szqueue_ptr(self); + + return LONG2NUM(queue_length(self, &sq->q)); +} + +/* + * Document-method: SizedQueue#num_waiting + * + * Returns the number of threads waiting on the queue. + */ + +static VALUE +rb_szqueue_num_waiting(VALUE self) +{ + struct rb_szqueue *sq = szqueue_ptr(self); + + return INT2NUM(sq->q.num_waiting + sq->num_waiting_push); +} + +/* + * Document-method: SizedQueue#empty? + * call-seq: empty? + * + * Returns +true+ if the queue is empty. + */ + +static VALUE +rb_szqueue_empty_p(VALUE self) +{ + struct rb_szqueue *sq = szqueue_ptr(self); + + return queue_length(self, &sq->q) == 0 ? Qtrue : Qfalse; +} + + +/* ConditionalVariable */ +struct rb_condvar { + struct list_head waitq; + rb_serial_t fork_gen; +}; + +/* + * Document-class: ConditionVariable + * + * ConditionVariable objects augment class Mutex. Using condition variables, + * it is possible to suspend while in the middle of a critical section until a + * resource becomes available. + * + * Example: + * + * mutex = Mutex.new + * resource = ConditionVariable.new + * + * a = Thread.new { + * mutex.synchronize { + * # Thread 'a' now needs the resource + * resource.wait(mutex) + * # 'a' can now have the resource + * } + * } + * + * b = Thread.new { + * mutex.synchronize { + * # Thread 'b' has finished using the resource + * resource.signal + * } + * } + */ + +static size_t +condvar_memsize(const void *ptr) +{ + return sizeof(struct rb_condvar); +} + +static const rb_data_type_t cv_data_type = { + "condvar", + {0, RUBY_TYPED_DEFAULT_FREE, condvar_memsize,}, + 0, 0, RUBY_TYPED_FREE_IMMEDIATELY|RUBY_TYPED_WB_PROTECTED +}; + +static struct rb_condvar * +condvar_ptr(VALUE self) +{ + struct rb_condvar *cv; + rb_serial_t fork_gen = GET_VM()->fork_gen; + + TypedData_Get_Struct(self, struct rb_condvar, &cv_data_type, cv); + + /* forked children can't reach into parent thread stacks */ + if (cv->fork_gen != fork_gen) { + cv->fork_gen = fork_gen; + list_head_init(&cv->waitq); + } + + return cv; +} + +static VALUE +condvar_alloc(VALUE klass) +{ + struct rb_condvar *cv; + VALUE obj; + + obj = TypedData_Make_Struct(klass, struct rb_condvar, &cv_data_type, cv); + list_head_init(&cv->waitq); + + return obj; +} + +/* + * Document-method: ConditionVariable::new + * + * Creates a new condition variable instance. + */ + +static VALUE +rb_condvar_initialize(VALUE self) +{ + struct rb_condvar *cv = condvar_ptr(self);; + list_head_init(&cv->waitq); + return self; +} + +struct sleep_call { + VALUE mutex; + VALUE timeout; +}; + +static ID id_sleep; + +static VALUE +do_sleep(VALUE args) +{ + struct sleep_call *p = (struct sleep_call *)args; + return rb_funcallv(p->mutex, id_sleep, 1, &p->timeout); +} + +static VALUE +delete_from_waitq(struct sync_waiter *w) +{ + list_del(&w->node); + + return Qnil; +} + +/* + * Document-method: ConditionVariable#wait + * call-seq: wait(mutex, timeout=nil) + * + * Releases the lock held in +mutex+ and waits; reacquires the lock on wakeup. + * + * If +timeout+ is given, this method returns after +timeout+ seconds passed, + * even if no other thread doesn't signal. + */ + +static VALUE +rb_condvar_wait(int argc, VALUE *argv, VALUE self) +{ + struct rb_condvar *cv = condvar_ptr(self); + VALUE mutex, timeout; + struct sleep_call args; + struct sync_waiter w; + + rb_scan_args(argc, argv, "11", &mutex, &timeout); + + args.mutex = mutex; + args.timeout = timeout; + w.th = GET_THREAD(); + list_add_tail(&cv->waitq, &w.node); + rb_ensure(do_sleep, (VALUE)&args, delete_from_waitq, (VALUE)&w); + + return self; +} + +/* + * Document-method: ConditionVariable#signal + * + * Wakes up the first thread in line waiting for this lock. + */ + +static VALUE +rb_condvar_signal(VALUE self) +{ + struct rb_condvar *cv = condvar_ptr(self); + wakeup_one(&cv->waitq); + return self; +} + +/* + * Document-method: ConditionVariable#broadcast + * + * Wakes up all threads waiting for this lock. + */ + +static VALUE +rb_condvar_broadcast(VALUE self) +{ + struct rb_condvar *cv = condvar_ptr(self); + wakeup_all(&cv->waitq); + return self; +} + +/* :nodoc: */ +static VALUE +undumpable(VALUE obj) +{ + rb_raise(rb_eTypeError, "can't dump %"PRIsVALUE, rb_obj_class(obj)); + UNREACHABLE; +} + +static VALUE +define_thread_class(VALUE outer, const char *name, VALUE super) +{ + VALUE klass = rb_define_class_under(outer, name, super); + rb_define_const(rb_cObject, name, klass); + return klass; +} + +static void +Init_thread_sync(void) +{ +#if 0 + rb_cMutex = rb_define_class("Mutex", rb_cObject); /* teach rdoc Mutex */ + rb_cConditionVariable = rb_define_class("ConditionVariable", rb_cObject); /* teach rdoc ConditionVariable */ + rb_cQueue = rb_define_class("Queue", rb_cObject); /* teach rdoc Queue */ + rb_cSizedQueue = rb_define_class("SizedQueue", rb_cObject); /* teach rdoc SizedQueue */ +#endif + +#define DEFINE_CLASS(name, super) \ + rb_c##name = define_thread_class(rb_cThread, #name, rb_c##super) + + /* Mutex */ + DEFINE_CLASS(Mutex, Object); + rb_define_alloc_func(rb_cMutex, mutex_alloc); + rb_define_method(rb_cMutex, "initialize", mutex_initialize, 0); + rb_define_method(rb_cMutex, "locked?", rb_mutex_locked_p, 0); + rb_define_method(rb_cMutex, "try_lock", rb_mutex_trylock, 0); + rb_define_method(rb_cMutex, "lock", rb_mutex_lock, 0); + rb_define_method(rb_cMutex, "unlock", rb_mutex_unlock, 0); + rb_define_method(rb_cMutex, "sleep", mutex_sleep, -1); + rb_define_method(rb_cMutex, "synchronize", rb_mutex_synchronize_m, 0); + rb_define_method(rb_cMutex, "owned?", rb_mutex_owned_p, 0); + + /* Queue */ + DEFINE_CLASS(Queue, Object); + rb_define_alloc_func(rb_cQueue, queue_alloc); + + rb_eClosedQueueError = rb_define_class("ClosedQueueError", rb_eStopIteration); + + rb_define_method(rb_cQueue, "initialize", rb_queue_initialize, 0); + rb_undef_method(rb_cQueue, "initialize_copy"); + rb_define_method(rb_cQueue, "marshal_dump", undumpable, 0); + rb_define_method(rb_cQueue, "close", rb_queue_close, 0); + rb_define_method(rb_cQueue, "closed?", rb_queue_closed_p, 0); + rb_define_method(rb_cQueue, "push", rb_queue_push, 1); + rb_define_method(rb_cQueue, "pop", rb_queue_pop, -1); + rb_define_method(rb_cQueue, "empty?", rb_queue_empty_p, 0); + rb_define_method(rb_cQueue, "clear", rb_queue_clear, 0); + rb_define_method(rb_cQueue, "length", rb_queue_length, 0); + rb_define_method(rb_cQueue, "num_waiting", rb_queue_num_waiting, 0); + + rb_define_alias(rb_cQueue, "enq", "push"); + rb_define_alias(rb_cQueue, "<<", "push"); + rb_define_alias(rb_cQueue, "deq", "pop"); + rb_define_alias(rb_cQueue, "shift", "pop"); + rb_define_alias(rb_cQueue, "size", "length"); + + DEFINE_CLASS(SizedQueue, Queue); + rb_define_alloc_func(rb_cSizedQueue, szqueue_alloc); + + rb_define_method(rb_cSizedQueue, "initialize", rb_szqueue_initialize, 1); + rb_define_method(rb_cSizedQueue, "close", rb_szqueue_close, 0); + rb_define_method(rb_cSizedQueue, "max", rb_szqueue_max_get, 0); + rb_define_method(rb_cSizedQueue, "max=", rb_szqueue_max_set, 1); + rb_define_method(rb_cSizedQueue, "push", rb_szqueue_push, -1); + rb_define_method(rb_cSizedQueue, "pop", rb_szqueue_pop, -1); + rb_define_method(rb_cSizedQueue, "empty?", rb_szqueue_empty_p, 0); + rb_define_method(rb_cSizedQueue, "clear", rb_szqueue_clear, 0); + rb_define_method(rb_cSizedQueue, "length", rb_szqueue_length, 0); + rb_define_method(rb_cSizedQueue, "num_waiting", rb_szqueue_num_waiting, 0); + + rb_define_alias(rb_cSizedQueue, "enq", "push"); + rb_define_alias(rb_cSizedQueue, "<<", "push"); + rb_define_alias(rb_cSizedQueue, "deq", "pop"); + rb_define_alias(rb_cSizedQueue, "shift", "pop"); + rb_define_alias(rb_cSizedQueue, "size", "length"); + + /* CVar */ + DEFINE_CLASS(ConditionVariable, Object); + rb_define_alloc_func(rb_cConditionVariable, condvar_alloc); + + id_sleep = rb_intern("sleep"); + + rb_define_method(rb_cConditionVariable, "initialize", rb_condvar_initialize, 0); + rb_undef_method(rb_cConditionVariable, "initialize_copy"); + rb_define_method(rb_cConditionVariable, "marshal_dump", undumpable, 0); + rb_define_method(rb_cConditionVariable, "wait", rb_condvar_wait, -1); + rb_define_method(rb_cConditionVariable, "signal", rb_condvar_signal, 0); + rb_define_method(rb_cConditionVariable, "broadcast", rb_condvar_broadcast, 0); + + rb_provide("thread.rb"); +} |