* ext/thread/thread.c: move definitions of Queue, SizedQueue

  and ConditionalVariables to thread_tools.c. In other wowrds,
  such classes are built-in.
  [Feature #8919]
  At first, I planned to embed only a Queue class.
  However, rubygems requires 'thread.rb' (rubygems are
  required at first, when launch MRI without --disable-gems).
  So most of people require 'thread.rb' as an embedded library.
  Now, ext/thread/thread.c is empty, only for a dummy for
  compatibility.
* thread.c: move a definition of Mutex class to thread_tools.c.
  And define Mutex class under Thread (so now Mutex is Thread::Mutex).
  Because other thread related classes are also defined under Thread.
  We remain ::Mutex as Thread::Mutex. Only an inspect result is changed.
* common.mk: add dependency from thread.o to thraed_tools.c.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51660 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

5 files changed, 1198 insertions, 1173 deletions

diff --git a/ChangeLog b/ChangeLog
index fd00ba1abc..e27b885242 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,26 @@
+Sat Aug 22 08:23:32 2015  Koichi Sasada  <ko1@atdot.net>
+
+	* ext/thread/thread.c: move definitions of Queue, SizedQueue
+	  and ConditionalVariables to thread_tools.c. In other wowrds,
+	  such classes are built-in.
+	  [Feature #8919]
+
+	  At first, I planned to embed only a Queue class.
+	  However, rubygems requires 'thread.rb' (rubygems are
+	  required at first, when launch MRI without --disable-gems).
+	  So most of people require 'thread.rb' as an embedded library.
+
+	  Now, ext/thread/thread.c is empty, only for a dummy for
+	  compatibility.
+
+	* thread.c: move a definition of Mutex class to thread_tools.c.
+
+	  And define Mutex class under Thread (so now Mutex is Thread::Mutex).
+	  Because other thread related classes are also defined under Thread.
+	  We remain ::Mutex as Thread::Mutex. Only an inspect result is changed.
+
+	* common.mk: add dependency from thread.o to thraed_tools.c.
+
 Sat Aug 22 05:31:37 2015  Koichi Sasada  <ko1@atdot.net>
 
 	* vm_opts.h, iseq.c, iseq.h: add compile option to force frozen
diff --git a/common.mk b/common.mk
index 635d125c60..19eeb9a31b 100644
--- a/common.mk
+++ b/common.mk
@@ -2249,6 +2249,7 @@ thread.$(OBJEXT): {$(VPATH)}thread.h
 thread.$(OBJEXT): {$(VPATH)}thread_$(THREAD_MODEL).c
 thread.$(OBJEXT): {$(VPATH)}thread_$(THREAD_MODEL).h
 thread.$(OBJEXT): {$(VPATH)}thread_native.h
+thread.$(OBJEXT): {$(VPATH)}thread_tools.c
 thread.$(OBJEXT): {$(VPATH)}timev.h
 thread.$(OBJEXT): {$(VPATH)}vm_core.h
 thread.$(OBJEXT): {$(VPATH)}vm_debug.h
diff --git a/ext/thread/thread.c b/ext/thread/thread.c
index de094acd91..9eef3b442e 100644
--- a/ext/thread/thread.c
+++ b/ext/thread/thread.c
@@ -1,658 +1,6 @@
 #include <ruby.h>
 
-enum {
-    CONDVAR_WAITERS,
-    END_CONDVAR
-};
-
-enum {
-    QUEUE_QUE,
-    QUEUE_WAITERS,
-    SZQUEUE_WAITERS,
-    SZQUEUE_MAX,
-    END_QUEUE
-};
-
-#define GET_CONDVAR_WAITERS(cv) get_array((cv), CONDVAR_WAITERS)
-
-#define GET_QUEUE_QUE(q)        get_array((q), QUEUE_QUE)
-#define GET_QUEUE_WAITERS(q)    get_array((q), QUEUE_WAITERS)
-#define GET_SZQUEUE_WAITERS(q)  get_array((q), SZQUEUE_WAITERS)
-#define GET_SZQUEUE_MAX(q)      RSTRUCT_GET((q), SZQUEUE_MAX)
-#define GET_SZQUEUE_ULONGMAX(q) NUM2ULONG(GET_SZQUEUE_MAX(q))
-
-static VALUE
-get_array(VALUE obj, int idx)
-{
-    VALUE ary = RSTRUCT_GET(obj, idx);
-    if (!RB_TYPE_P(ary, T_ARRAY)) {
-	rb_raise(rb_eTypeError, "%+"PRIsVALUE" not initialized", obj);
-    }
-    return ary;
-}
-
-static VALUE
-ary_buf_new(void)
-{
-    return rb_ary_tmp_new(1);
-}
-
-static void
-wakeup_first_thread(VALUE list)
-{
-    VALUE thread;
-
-    while (!NIL_P(thread = rb_ary_shift(list))) {
-	if (RTEST(rb_thread_wakeup_alive(thread))) break;
-    }
-}
-
-static void
-wakeup_all_threads(VALUE list)
-{
-    VALUE thread;
-    long i;
-
-    for (i=0; i<RARRAY_LEN(list); i++) {
-	thread = RARRAY_AREF(list, i);
-	rb_thread_wakeup_alive(thread);
-    }
-    rb_ary_clear(list);
-}
-
-/*
- *  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:
- *
- *    require 'thread'
- *
- *    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
- *	 }
- *    }
- */
-
-/*
- * Document-method: ConditionVariable::new
- *
- * Creates a new condition variable instance.
- */
-
-static VALUE
-rb_condvar_initialize(VALUE self)
-{
-    RSTRUCT_SET(self, CONDVAR_WAITERS, ary_buf_new());
-    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_funcall2(p->mutex, id_sleep, 1, &p->timeout);
-}
-
-static VALUE
-delete_current_thread(VALUE ary)
-{
-    return rb_ary_delete(ary, rb_thread_current());
-}
-
-/*
- * 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)
-{
-    VALUE waiters = GET_CONDVAR_WAITERS(self);
-    VALUE mutex, timeout;
-    struct sleep_call args;
-
-    rb_scan_args(argc, argv, "11", &mutex, &timeout);
-
-    args.mutex   = mutex;
-    args.timeout = timeout;
-    rb_ary_push(waiters, rb_thread_current());
-    rb_ensure(do_sleep, (VALUE)&args, delete_current_thread, waiters);
-
-    return self;
-}
-
-/*
- * Document-method: ConditionVariable#signal
- *
- * Wakes up the first thread in line waiting for this lock.
- */
-
-static VALUE
-rb_condvar_signal(VALUE self)
-{
-    wakeup_first_thread(GET_CONDVAR_WAITERS(self));
-    return self;
-}
-
-/*
- * Document-method: ConditionVariable#broadcast
- *
- * Wakes up all threads waiting for this lock.
- */
-
-static VALUE
-rb_condvar_broadcast(VALUE self)
-{
-    wakeup_all_threads(GET_CONDVAR_WAITERS(self));
-    return self;
-}
-
-/*
- *  Document-class: Queue
- *
- *  This class provides a way to synchronize communication between threads.
- *
- *  Example:
- *
- *	require 'thread'
- *    	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)
-{
-    RSTRUCT_SET(self, QUEUE_QUE, ary_buf_new());
-    RSTRUCT_SET(self, QUEUE_WAITERS, ary_buf_new());
-    return self;
-}
-
-static VALUE
-queue_do_push(VALUE self, VALUE obj)
-{
-    rb_ary_push(GET_QUEUE_QUE(self), obj);
-    wakeup_first_thread(GET_QUEUE_WAITERS(self));
-    return self;
-}
-
-/*
- * 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, obj);
-}
-
-static unsigned long
-queue_length(VALUE self)
-{
-    VALUE que = GET_QUEUE_QUE(self);
-    return RARRAY_LEN(que);
-}
-
-static unsigned long
-queue_num_waiting(VALUE self)
-{
-    VALUE waiters = GET_QUEUE_WAITERS(self);
-    return RARRAY_LEN(waiters);
-}
-
-struct waiting_delete {
-    VALUE waiting;
-    VALUE th;
-};
-
-static VALUE
-queue_delete_from_waiting(struct waiting_delete *p)
-{
-    rb_ary_delete(p->waiting, p->th);
-    return Qnil;
-}
-
-static VALUE
-queue_sleep(VALUE arg)
-{
-    rb_thread_sleep_deadly();
-    return Qnil;
-}
-
-static VALUE
-queue_do_pop(VALUE self, int should_block)
-{
-    struct waiting_delete args;
-    args.waiting = GET_QUEUE_WAITERS(self);
-    args.th	 = rb_thread_current();
-
-    while (queue_length(self) == 0) {
-	if (!should_block) {
-	    rb_raise(rb_eThreadError, "queue empty");
-	}
-	rb_ary_push(args.waiting, args.th);
-	rb_ensure(queue_sleep, (VALUE)0, queue_delete_from_waiting, (VALUE)&args);
-    }
-
-    return rb_ary_shift(GET_QUEUE_QUE(self));
-}
-
-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 an
- * exception 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, 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) == 0 ? Qtrue : Qfalse;
-}
-
-/*
- * Document-method: Queue#clear
- *
- * Removes all objects from the queue.
- */
-
-static VALUE
-rb_queue_clear(VALUE self)
-{
-    rb_ary_clear(GET_QUEUE_QUE(self));
-    return self;
-}
-
-/*
- * Document-method: Queue#length
- * call-seq:
- *   length
- *   size
- *
- * Returns the length of the queue.
- */
-
-static VALUE
-rb_queue_length(VALUE self)
-{
-    unsigned long len = queue_length(self);
-    return ULONG2NUM(len);
-}
-
-/*
- * Document-method: Queue#num_waiting
- *
- * Returns the number of threads waiting on the queue.
- */
-
-static VALUE
-rb_queue_num_waiting(VALUE self)
-{
-    unsigned long len = queue_num_waiting(self);
-    return ULONG2NUM(len);
-}
-
-/*
- *  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;
-
-    max = NUM2LONG(vmax);
-    if (max <= 0) {
-	rb_raise(rb_eArgError, "queue size must be positive");
-    }
-
-    RSTRUCT_SET(self, QUEUE_QUE, ary_buf_new());
-    RSTRUCT_SET(self, QUEUE_WAITERS, ary_buf_new());
-    RSTRUCT_SET(self, SZQUEUE_WAITERS, ary_buf_new());
-    RSTRUCT_SET(self, SZQUEUE_MAX, vmax);
-
-    return self;
-}
-
-/*
- * Document-method: SizedQueue#max
- *
- * Returns the maximum size of the queue.
- */
-
-static VALUE
-rb_szqueue_max_get(VALUE self)
-{
-    return GET_SZQUEUE_MAX(self);
-}
-
-/*
- * 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), diff = 0;
-    VALUE t;
-
-    if (max <= 0) {
-	rb_raise(rb_eArgError, "queue size must be positive");
-    }
-    if ((unsigned long)max > GET_SZQUEUE_ULONGMAX(self)) {
-	diff = max - GET_SZQUEUE_ULONGMAX(self);
-    }
-    RSTRUCT_SET(self, SZQUEUE_MAX, vmax);
-    while (diff-- > 0 && !NIL_P(t = rb_ary_shift(GET_SZQUEUE_WAITERS(self)))) {
-	rb_thread_wakeup_alive(t);
-    }
-    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 an exception is raised.
- */
-
-static VALUE
-rb_szqueue_push(int argc, VALUE *argv, VALUE self)
-{
-    struct waiting_delete args;
-    int should_block = szqueue_push_should_block(argc, argv);
-    args.waiting = GET_SZQUEUE_WAITERS(self);
-    args.th      = rb_thread_current();
-
-    while (queue_length(self) >= GET_SZQUEUE_ULONGMAX(self)) {
-	if (!should_block) {
-	    rb_raise(rb_eThreadError, "queue full");
-	}
-	rb_ary_push(args.waiting, args.th);
-	rb_ensure((VALUE (*)())rb_thread_sleep_deadly, (VALUE)0, queue_delete_from_waiting, (VALUE)&args);
-    }
-    return queue_do_push(self, argv[0]);
-}
-
-static VALUE
-szqueue_do_pop(VALUE self, int should_block)
-{
-    VALUE retval = queue_do_pop(self, should_block);
-
-    if (queue_length(self) < GET_SZQUEUE_ULONGMAX(self)) {
-	wakeup_first_thread(GET_SZQUEUE_WAITERS(self));
-    }
-
-    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 an
- * exception 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: Queue#clear
- *
- * Removes all objects from the queue.
- */
-
-static VALUE
-rb_szqueue_clear(VALUE self)
-{
-    rb_ary_clear(GET_QUEUE_QUE(self));
-    wakeup_all_threads(GET_SZQUEUE_WAITERS(self));
-    return self;
-}
-
-/*
- * Document-method: SizedQueue#num_waiting
- *
- * Returns the number of threads waiting on the queue.
- */
-
-static VALUE
-rb_szqueue_num_waiting(VALUE self)
-{
-    long len = queue_num_waiting(self);
-    VALUE waiters = GET_SZQUEUE_WAITERS(self);
-    len += RARRAY_LEN(waiters);
-    return ULONG2NUM(len);
-}
-
-#ifndef UNDER_THREAD
-#define UNDER_THREAD 1
-#endif
-
-/* :nodoc: */
-static VALUE
-undumpable(VALUE obj)
-{
-    rb_raise(rb_eTypeError, "can't dump %"PRIsVALUE, rb_obj_class(obj));
-    UNREACHABLE;
-}
-
 void
 Init_thread(void)
 {
-#if UNDER_THREAD
-#define ALIAS_GLOBAL_CONST(name) do {	              \
-	ID id = rb_intern_const(#name);	              \
-	if (!rb_const_defined_at(rb_cObject, id)) {   \
-	    rb_const_set(rb_cObject, id, rb_c##name); \
-	}                                             \
-    } while (0)
-#define OUTER rb_cThread
-#else
-#define ALIAS_GLOBAL_CONST(name) do { /* nothing */ } while (0)
-#define OUTER 0
-#endif
-
-    VALUE rb_cConditionVariable = rb_struct_define_without_accessor_under(
-	OUTER,
-	"ConditionVariable", rb_cObject, rb_struct_alloc_noinit,
-	"waiters", NULL);
-    VALUE rb_cQueue = rb_struct_define_without_accessor_under(
-	OUTER,
-	"Queue", rb_cObject, rb_struct_alloc_noinit,
-	"que", "waiters", NULL);
-    VALUE rb_cSizedQueue = rb_struct_define_without_accessor_under(
-	OUTER,
-	"SizedQueue", rb_cQueue, rb_struct_alloc_noinit,
-	"que", "waiters", "queue_waiters", "size", NULL);
-
-#if 0
-    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
-
-    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_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, "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);
-
-    /* Alias for #push. */
-    rb_define_alias(rb_cQueue, "enq", "push");
-    /* Alias for #push. */
-    rb_define_alias(rb_cQueue, "<<", "push");
-    /* Alias for #pop. */
-    rb_define_alias(rb_cQueue, "deq", "pop");
-    /* Alias for #pop. */
-    rb_define_alias(rb_cQueue, "shift", "pop");
-    /* Alias for #length. */
-    rb_define_alias(rb_cQueue, "size", "length");
-
-    rb_define_method(rb_cSizedQueue, "initialize", rb_szqueue_initialize, 1);
-    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, "clear", rb_szqueue_clear, 0);
-    rb_define_method(rb_cSizedQueue, "num_waiting", rb_szqueue_num_waiting, 0);
-
-    /* Alias for #push. */
-    rb_define_alias(rb_cSizedQueue, "enq", "push");
-    /* Alias for #push. */
-    rb_define_alias(rb_cSizedQueue, "<<", "push");
-    /* Alias for #pop. */
-    rb_define_alias(rb_cSizedQueue, "deq", "pop");
-    /* Alias for #pop. */
-    rb_define_alias(rb_cSizedQueue, "shift", "pop");
-
-    rb_provide("thread.rb");
-    ALIAS_GLOBAL_CONST(ConditionVariable);
-    ALIAS_GLOBAL_CONST(Queue);
-    ALIAS_GLOBAL_CONST(SizedQueue);
 }
diff --git a/thread.c b/thread.c
index f64a45d708..e591e65dc2 100644
--- a/thread.c
+++ b/thread.c
@@ -75,7 +75,6 @@
 #define THREAD_DEBUG 0
 #endif
 
-VALUE rb_cMutex;
 VALUE rb_cThreadShield;
 
 static VALUE sym_immediate;
@@ -332,6 +331,8 @@ rb_thread_debug(
 }
 #endif
 
+#include "thread_tools.c"
+
 void
 rb_vm_gvl_destroy(rb_vm_t *vm)
 {
@@ -445,21 +446,6 @@ terminate_all(rb_vm_t *vm, const rb_thread_t *main_thread)
     }
 }
 
-typedef struct rb_mutex_struct
-{
-    rb_nativethread_lock_t lock;
-    rb_nativethread_cond_t cond;
-    struct rb_thread_struct volatile *th;
-    struct rb_mutex_struct *next_mutex;
-    int cond_waiting;
-    int allow_trap;
-} rb_mutex_t;
-
-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);
-static const char* rb_mutex_unlock_th(rb_mutex_t *mutex, rb_thread_t volatile *th);
-
 void
 rb_threadptr_unlock_all_locking_mutexes(rb_thread_t *th)
 {
@@ -4140,500 +4126,6 @@ thgroup_add(VALUE group, VALUE thread)
     return group;
 }
 
-
-/*
- *  Document-class: Mutex
- *
- *  Mutex implements a simple semaphore that can be used to coordinate access to
- *  shared data from multiple concurrent threads.
- *
- *  Example:
- *
- *    require 'thread'
- *    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 void
-mutex_free(void *ptr)
-{
-    if (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);
-	}
-	native_mutex_destroy(&mutex->lock);
-	native_cond_destroy(&mutex->cond);
-    }
-    ruby_xfree(ptr);
-}
-
-static size_t
-mutex_memsize(const void *ptr)
-{
-    return ptr ? sizeof(rb_mutex_t) : 0;
-}
-
-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);
-    native_mutex_initialize(&mutex->lock);
-    native_cond_initialize(&mutex->cond, RB_CONDATTR_CLOCK_MONOTONIC);
-    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);
-
-    native_mutex_lock(&mutex->lock);
-    if (mutex->th == 0) {
-	rb_thread_t *th = GET_THREAD();
-	mutex->th = th;
-	locked = Qtrue;
-
-	mutex_locked(th, self);
-    }
-    native_mutex_unlock(&mutex->lock);
-
-    return locked;
-}
-
-static int
-lock_func(rb_thread_t *th, rb_mutex_t *mutex, int timeout_ms)
-{
-    int interrupted = 0;
-    int err = 0;
-
-    mutex->cond_waiting++;
-    for (;;) {
-	if (!mutex->th) {
-	    mutex->th = th;
-	    break;
-	}
-	if (RUBY_VM_INTERRUPTED(th)) {
-	    interrupted = 1;
-	    break;
-	}
-	if (err == ETIMEDOUT) {
-	    interrupted = 2;
-	    break;
-	}
-
-	if (timeout_ms) {
-	    struct timespec timeout_rel;
-	    struct timespec timeout;
-
-	    timeout_rel.tv_sec = 0;
-	    timeout_rel.tv_nsec = timeout_ms * 1000 * 1000;
-	    timeout = native_cond_timeout(&mutex->cond, timeout_rel);
-	    err = native_cond_timedwait(&mutex->cond, &mutex->lock, &timeout);
-	}
-	else {
-	    native_cond_wait(&mutex->cond, &mutex->lock);
-	    err = 0;
-	}
-    }
-    mutex->cond_waiting--;
-
-    return interrupted;
-}
-
-static void
-lock_interrupt(void *ptr)
-{
-    rb_mutex_t *mutex = (rb_mutex_t *)ptr;
-    native_mutex_lock(&mutex->lock);
-    if (mutex->cond_waiting > 0)
-	native_cond_broadcast(&mutex->cond);
-    native_mutex_unlock(&mutex->lock);
-}
-
-/*
- * 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;
-
-/*
- * 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)
-{
-    rb_thread_t *th = GET_THREAD();
-    rb_mutex_t *mutex;
-    GetMutexPtr(self, mutex);
-
-    /* When running trap handler */
-    if (!mutex->allow_trap && th->interrupt_mask & TRAP_INTERRUPT_MASK) {
-	rb_raise(rb_eThreadError, "can't be called from trap context");
-    }
-
-    if (rb_mutex_trylock(self) == Qfalse) {
-	if (mutex->th == th) {
-	    rb_raise(rb_eThreadError, "deadlock; recursive locking");
-	}
-
-	while (mutex->th != th) {
-	    int interrupted;
-	    enum rb_thread_status prev_status = th->status;
-	    volatile int timeout_ms = 0;
-	    struct rb_unblock_callback oldubf;
-
-	    set_unblock_function(th, lock_interrupt, mutex, &oldubf, FALSE);
-	    th->status = THREAD_STOPPED_FOREVER;
-	    th->locking_mutex = self;
-
-	    native_mutex_lock(&mutex->lock);
-	    th->vm->sleeper++;
-	    /*
-	     * Carefully! while some contended threads are in lock_func(),
-	     * vm->sleepr 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_ms = 100;
-		patrol_thread = th;
-	    }
-
-	    GVL_UNLOCK_BEGIN();
-	    interrupted = lock_func(th, mutex, (int)timeout_ms);
-	    native_mutex_unlock(&mutex->lock);
-	    GVL_UNLOCK_END();
-
-	    if (patrol_thread == th)
-		patrol_thread = NULL;
-
-	    reset_unblock_function(th, &oldubf);
-
-	    th->locking_mutex = Qfalse;
-	    if (mutex->th && interrupted == 2) {
-		rb_check_deadlock(th->vm);
-	    }
-	    if (th->status == THREAD_STOPPED_FOREVER) {
-		th->status = prev_status;
-	    }
-	    th->vm->sleeper--;
-
-	    if (mutex->th == th) mutex_locked(th, self);
-
-	    if (interrupted) {
-		RUBY_VM_CHECK_INTS_BLOCKING(th);
-	    }
-	}
-    }
-    return self;
-}
-
-/*
- * 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;
-
-    native_mutex_lock(&mutex->lock);
-
-    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 {
-	mutex->th = 0;
-	if (mutex->cond_waiting > 0)
-	    native_cond_signal(&mutex->cond);
-    }
-
-    native_mutex_unlock(&mutex->lock);
-
-    if (!err) {
-	rb_mutex_t *volatile *th_mutex = &th->keeping_mutexes;
-	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;
-}
-
-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;
-    }
-}
-
-static VALUE
-rb_mutex_sleep_forever(VALUE time)
-{
-    sleep_forever(GET_THREAD(), 1, 0); /* permit spurious check */
-    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, rb_mutex_lock, self);
-    }
-    else {
-	rb_ensure(rb_mutex_wait_for, (VALUE)&t, rb_mutex_lock, self);
-    }
-    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)
-{
-    rb_mutex_t *m;
-    GetMutexPtr(self, m);
-
-    m->allow_trap = val;
-}
-
 /*
  * Document-class: ThreadShield
  */
@@ -5136,17 +4628,6 @@ Init_Thread(void)
 	rb_define_const(cThGroup, "Default", th->thgroup);
     }
 
-    rb_cMutex = rb_define_class("Mutex", rb_cObject);
-    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);
-
     recursive_key = rb_intern("__recursive_key__");
     rb_eThreadError = rb_define_class("ThreadError", rb_eStandardError);
 
@@ -5174,6 +4655,8 @@ Init_Thread(void)
 
     /* suppress warnings on cygwin, mingw and mswin.*/
     (void)native_mutex_trylock;
+
+    Init_thread_tools();
 }
 
 int
diff --git a/thread_tools.c b/thread_tools.c
new file mode 100644
index 0000000000..eee185e6c3
--- /dev/null
+++ b/thread_tools.c
@@ -0,0 +1,1170 @@
+/* included by thraed.c */
+
+VALUE rb_cMutex, rb_cQueue, rb_cSizedQueue, rb_cConditionVariable;
+
+/* Mutex */
+
+typedef struct rb_mutex_struct {
+    rb_nativethread_lock_t lock;
+    rb_nativethread_cond_t cond;
+    struct rb_thread_struct volatile *th;
+    struct rb_mutex_struct *next_mutex;
+    int cond_waiting;
+    int allow_trap;
+} rb_mutex_t;
+
+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);
+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:
+ *
+ *    require 'thread'
+ *    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 void
+mutex_free(void *ptr)
+{
+    if (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);
+	}
+	native_mutex_destroy(&mutex->lock);
+	native_cond_destroy(&mutex->cond);
+    }
+    ruby_xfree(ptr);
+}
+
+static size_t
+mutex_memsize(const void *ptr)
+{
+    return ptr ? sizeof(rb_mutex_t) : 0;
+}
+
+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);
+    native_mutex_initialize(&mutex->lock);
+    native_cond_initialize(&mutex->cond, RB_CONDATTR_CLOCK_MONOTONIC);
+    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);
+
+    native_mutex_lock(&mutex->lock);
+    if (mutex->th == 0) {
+	rb_thread_t *th = GET_THREAD();
+	mutex->th = th;
+	locked = Qtrue;
+
+	mutex_locked(th, self);
+    }
+    native_mutex_unlock(&mutex->lock);
+
+    return locked;
+}
+
+static int
+lock_func(rb_thread_t *th, rb_mutex_t *mutex, int timeout_ms)
+{
+    int interrupted = 0;
+    int err = 0;
+
+    mutex->cond_waiting++;
+    for (;;) {
+	if (!mutex->th) {
+	    mutex->th = th;
+	    break;
+	}
+	if (RUBY_VM_INTERRUPTED(th)) {
+	    interrupted = 1;
+	    break;
+	}
+	if (err == ETIMEDOUT) {
+	    interrupted = 2;
+	    break;
+	}
+
+	if (timeout_ms) {
+	    struct timespec timeout_rel;
+	    struct timespec timeout;
+
+	    timeout_rel.tv_sec = 0;
+	    timeout_rel.tv_nsec = timeout_ms * 1000 * 1000;
+	    timeout = native_cond_timeout(&mutex->cond, timeout_rel);
+	    err = native_cond_timedwait(&mutex->cond, &mutex->lock, &timeout);
+	}
+	else {
+	    native_cond_wait(&mutex->cond, &mutex->lock);
+	    err = 0;
+	}
+    }
+    mutex->cond_waiting--;
+
+    return interrupted;
+}
+
+static void
+lock_interrupt(void *ptr)
+{
+    rb_mutex_t *mutex = (rb_mutex_t *)ptr;
+    native_mutex_lock(&mutex->lock);
+    if (mutex->cond_waiting > 0)
+	native_cond_broadcast(&mutex->cond);
+    native_mutex_unlock(&mutex->lock);
+}
+
+/*
+ * 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;
+
+/*
+ * 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)
+{
+    rb_thread_t *th = GET_THREAD();
+    rb_mutex_t *mutex;
+    GetMutexPtr(self, mutex);
+
+    /* When running trap handler */
+    if (!mutex->allow_trap && th->interrupt_mask & TRAP_INTERRUPT_MASK) {
+	rb_raise(rb_eThreadError, "can't be called from trap context");
+    }
+
+    if (rb_mutex_trylock(self) == Qfalse) {
+	if (mutex->th == th) {
+	    rb_raise(rb_eThreadError, "deadlock; recursive locking");
+	}
+
+	while (mutex->th != th) {
+	    int interrupted;
+	    enum rb_thread_status prev_status = th->status;
+	    volatile int timeout_ms = 0;
+	    struct rb_unblock_callback oldubf;
+
+	    set_unblock_function(th, lock_interrupt, mutex, &oldubf, FALSE);
+	    th->status = THREAD_STOPPED_FOREVER;
+	    th->locking_mutex = self;
+
+	    native_mutex_lock(&mutex->lock);
+	    th->vm->sleeper++;
+	    /*
+	     * Carefully! while some contended threads are in lock_func(),
+	     * vm->sleepr 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_ms = 100;
+		patrol_thread = th;
+	    }
+
+	    GVL_UNLOCK_BEGIN();
+	    interrupted = lock_func(th, mutex, (int)timeout_ms);
+	    native_mutex_unlock(&mutex->lock);
+	    GVL_UNLOCK_END();
+
+	    if (patrol_thread == th)
+		patrol_thread = NULL;
+
+	    reset_unblock_function(th, &oldubf);
+
+	    th->locking_mutex = Qfalse;
+	    if (mutex->th && interrupted == 2) {
+		rb_check_deadlock(th->vm);
+	    }
+	    if (th->status == THREAD_STOPPED_FOREVER) {
+		th->status = prev_status;
+	    }
+	    th->vm->sleeper--;
+
+	    if (mutex->th == th) mutex_locked(th, self);
+
+	    if (interrupted) {
+		RUBY_VM_CHECK_INTS_BLOCKING(th);
+	    }
+	}
+    }
+    return self;
+}
+
+/*
+ * 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;
+
+    native_mutex_lock(&mutex->lock);
+
+    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 {
+	mutex->th = 0;
+	if (mutex->cond_waiting > 0)
+	    native_cond_signal(&mutex->cond);
+    }
+
+    native_mutex_unlock(&mutex->lock);
+
+    if (!err) {
+	rb_mutex_t *volatile *th_mutex = &th->keeping_mutexes;
+	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;
+}
+
+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;
+    }
+}
+
+static VALUE
+rb_mutex_sleep_forever(VALUE time)
+{
+    sleep_forever(GET_THREAD(), 1, 0); /* permit spurious check */
+    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, rb_mutex_lock, self);
+    }
+    else {
+	rb_ensure(rb_mutex_wait_for, (VALUE)&t, rb_mutex_lock, self);
+    }
+    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)
+{
+    rb_mutex_t *m;
+    GetMutexPtr(self, m);
+
+    m->allow_trap = val;
+}
+
+/* Queue */
+
+enum {
+    QUEUE_QUE,
+    QUEUE_WAITERS,
+    SZQUEUE_WAITERS,
+    SZQUEUE_MAX,
+    END_QUEUE
+};
+
+#define GET_QUEUE_QUE(q)        get_array((q), QUEUE_QUE)
+#define GET_QUEUE_WAITERS(q)    get_array((q), QUEUE_WAITERS)
+#define GET_SZQUEUE_WAITERS(q)  get_array((q), SZQUEUE_WAITERS)
+#define GET_SZQUEUE_MAX(q)      RSTRUCT_GET((q), SZQUEUE_MAX)
+#define GET_SZQUEUE_ULONGMAX(q) NUM2ULONG(GET_SZQUEUE_MAX(q))
+
+static VALUE
+ary_buf_new(void)
+{
+    return rb_ary_tmp_new(1);
+}
+
+static VALUE
+get_array(VALUE obj, int idx)
+{
+    VALUE ary = RSTRUCT_GET(obj, idx);
+    if (!RB_TYPE_P(ary, T_ARRAY)) {
+	rb_raise(rb_eTypeError, "%+"PRIsVALUE" not initialized", obj);
+    }
+    return ary;
+}
+
+static void
+wakeup_first_thread(VALUE list)
+{
+    VALUE thread;
+
+    while (!NIL_P(thread = rb_ary_shift(list))) {
+	if (RTEST(rb_thread_wakeup_alive(thread))) break;
+    }
+}
+
+static void
+wakeup_all_threads(VALUE list)
+{
+    VALUE thread;
+    long i;
+
+    for (i=0; i<RARRAY_LEN(list); i++) {
+	thread = RARRAY_AREF(list, i);
+	rb_thread_wakeup_alive(thread);
+    }
+    rb_ary_clear(list);
+}
+
+/*
+ *  Document-class: Queue
+ *
+ *  This class provides a way to synchronize communication between threads.
+ *
+ *  Example:
+ *
+ *	require 'thread'
+ *    	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)
+{
+    RSTRUCT_SET(self, QUEUE_QUE, ary_buf_new());
+    RSTRUCT_SET(self, QUEUE_WAITERS, ary_buf_new());
+    return self;
+}
+
+static VALUE
+queue_do_push(VALUE self, VALUE obj)
+{
+    rb_ary_push(GET_QUEUE_QUE(self), obj);
+    wakeup_first_thread(GET_QUEUE_WAITERS(self));
+    return self;
+}
+
+/*
+ * 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, obj);
+}
+
+static unsigned long
+queue_length(VALUE self)
+{
+    VALUE que = GET_QUEUE_QUE(self);
+    return RARRAY_LEN(que);
+}
+
+static unsigned long
+queue_num_waiting(VALUE self)
+{
+    VALUE waiters = GET_QUEUE_WAITERS(self);
+    return RARRAY_LEN(waiters);
+}
+
+struct waiting_delete {
+    VALUE waiting;
+    VALUE th;
+};
+
+static VALUE
+queue_delete_from_waiting(struct waiting_delete *p)
+{
+    rb_ary_delete(p->waiting, p->th);
+    return Qnil;
+}
+
+static VALUE
+queue_sleep(VALUE arg)
+{
+    rb_thread_sleep_deadly();
+    return Qnil;
+}
+
+static VALUE
+queue_do_pop(VALUE self, int should_block)
+{
+    struct waiting_delete args;
+    args.waiting = GET_QUEUE_WAITERS(self);
+    args.th	 = rb_thread_current();
+
+    while (queue_length(self) == 0) {
+	if (!should_block) {
+	    rb_raise(rb_eThreadError, "queue empty");
+	}
+	rb_ary_push(args.waiting, args.th);
+	rb_ensure(queue_sleep, (VALUE)0, queue_delete_from_waiting, (VALUE)&args);
+    }
+
+    return rb_ary_shift(GET_QUEUE_QUE(self));
+}
+
+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 an
+ * exception 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, 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) == 0 ? Qtrue : Qfalse;
+}
+
+/*
+ * Document-method: Queue#clear
+ *
+ * Removes all objects from the queue.
+ */
+
+static VALUE
+rb_queue_clear(VALUE self)
+{
+    rb_ary_clear(GET_QUEUE_QUE(self));
+    return self;
+}
+
+/*
+ * Document-method: Queue#length
+ * call-seq:
+ *   length
+ *   size
+ *
+ * Returns the length of the queue.
+ */
+
+static VALUE
+rb_queue_length(VALUE self)
+{
+    unsigned long len = queue_length(self);
+    return ULONG2NUM(len);
+}
+
+/*
+ * Document-method: Queue#num_waiting
+ *
+ * Returns the number of threads waiting on the queue.
+ */
+
+static VALUE
+rb_queue_num_waiting(VALUE self)
+{
+    unsigned long len = queue_num_waiting(self);
+    return ULONG2NUM(len);
+}
+
+/*
+ *  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;
+
+    max = NUM2LONG(vmax);
+    if (max <= 0) {
+	rb_raise(rb_eArgError, "queue size must be positive");
+    }
+
+    RSTRUCT_SET(self, QUEUE_QUE, ary_buf_new());
+    RSTRUCT_SET(self, QUEUE_WAITERS, ary_buf_new());
+    RSTRUCT_SET(self, SZQUEUE_WAITERS, ary_buf_new());
+    RSTRUCT_SET(self, SZQUEUE_MAX, vmax);
+
+    return self;
+}
+
+/*
+ * Document-method: SizedQueue#max
+ *
+ * Returns the maximum size of the queue.
+ */
+
+static VALUE
+rb_szqueue_max_get(VALUE self)
+{
+    return GET_SZQUEUE_MAX(self);
+}
+
+/*
+ * 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), diff = 0;
+    VALUE t;
+
+    if (max <= 0) {
+	rb_raise(rb_eArgError, "queue size must be positive");
+    }
+    if ((unsigned long)max > GET_SZQUEUE_ULONGMAX(self)) {
+	diff = max - GET_SZQUEUE_ULONGMAX(self);
+    }
+    RSTRUCT_SET(self, SZQUEUE_MAX, vmax);
+    while (diff-- > 0 && !NIL_P(t = rb_ary_shift(GET_SZQUEUE_WAITERS(self)))) {
+	rb_thread_wakeup_alive(t);
+    }
+    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 an exception is raised.
+ */
+
+static VALUE
+rb_szqueue_push(int argc, VALUE *argv, VALUE self)
+{
+    struct waiting_delete args;
+    int should_block = szqueue_push_should_block(argc, argv);
+    args.waiting = GET_SZQUEUE_WAITERS(self);
+    args.th      = rb_thread_current();
+
+    while (queue_length(self) >= GET_SZQUEUE_ULONGMAX(self)) {
+	if (!should_block) {
+	    rb_raise(rb_eThreadError, "queue full");
+	}
+	rb_ary_push(args.waiting, args.th);
+	rb_ensure((VALUE (*)())rb_thread_sleep_deadly, (VALUE)0, queue_delete_from_waiting, (VALUE)&args);
+    }
+    return queue_do_push(self, argv[0]);
+}
+
+static VALUE
+szqueue_do_pop(VALUE self, int should_block)
+{
+    VALUE retval = queue_do_pop(self, should_block);
+
+    if (queue_length(self) < GET_SZQUEUE_ULONGMAX(self)) {
+	wakeup_first_thread(GET_SZQUEUE_WAITERS(self));
+    }
+
+    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 an
+ * exception 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: Queue#clear
+ *
+ * Removes all objects from the queue.
+ */
+
+static VALUE
+rb_szqueue_clear(VALUE self)
+{
+    rb_ary_clear(GET_QUEUE_QUE(self));
+    wakeup_all_threads(GET_SZQUEUE_WAITERS(self));
+    return self;
+}
+
+/*
+ * Document-method: SizedQueue#num_waiting
+ *
+ * Returns the number of threads waiting on the queue.
+ */
+
+static VALUE
+rb_szqueue_num_waiting(VALUE self)
+{
+    long len = queue_num_waiting(self);
+    VALUE waiters = GET_SZQUEUE_WAITERS(self);
+    len += RARRAY_LEN(waiters);
+    return ULONG2NUM(len);
+}
+
+/* ConditionalVariable */
+
+enum {
+    CONDVAR_WAITERS,
+    END_CONDVAR
+};
+
+#define GET_CONDVAR_WAITERS(cv) get_array((cv), CONDVAR_WAITERS)
+
+/*
+ *  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:
+ *
+ *    require 'thread'
+ *
+ *    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
+ *	 }
+ *    }
+ */
+
+/*
+ * Document-method: ConditionVariable::new
+ *
+ * Creates a new condition variable instance.
+ */
+
+static VALUE
+rb_condvar_initialize(VALUE self)
+{
+    RSTRUCT_SET(self, CONDVAR_WAITERS, ary_buf_new());
+    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_funcall2(p->mutex, id_sleep, 1, &p->timeout);
+}
+
+static VALUE
+delete_current_thread(VALUE ary)
+{
+    return rb_ary_delete(ary, rb_thread_current());
+}
+
+/*
+ * 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)
+{
+    VALUE waiters = GET_CONDVAR_WAITERS(self);
+    VALUE mutex, timeout;
+    struct sleep_call args;
+
+    rb_scan_args(argc, argv, "11", &mutex, &timeout);
+
+    args.mutex   = mutex;
+    args.timeout = timeout;
+    rb_ary_push(waiters, rb_thread_current());
+    rb_ensure(do_sleep, (VALUE)&args, delete_current_thread, waiters);
+
+    return self;
+}
+
+/*
+ * Document-method: ConditionVariable#signal
+ *
+ * Wakes up the first thread in line waiting for this lock.
+ */
+
+static VALUE
+rb_condvar_signal(VALUE self)
+{
+    wakeup_first_thread(GET_CONDVAR_WAITERS(self));
+    return self;
+}
+
+/*
+ * Document-method: ConditionVariable#broadcast
+ *
+ * Wakes up all threads waiting for this lock.
+ */
+
+static VALUE
+rb_condvar_broadcast(VALUE self)
+{
+    wakeup_all_threads(GET_CONDVAR_WAITERS(self));
+    return self;
+}
+
+/* :nodoc: */
+static VALUE
+undumpable(VALUE obj)
+{
+    rb_raise(rb_eTypeError, "can't dump %"PRIsVALUE, rb_obj_class(obj));
+    UNREACHABLE;
+}
+
+static void
+Init_thread_tools(void)
+{
+#if 0
+    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
+
+    /* Mutex */
+    rb_cMutex = rb_define_class_under(rb_cThread, "Mutex", rb_cObject);
+    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 */
+    rb_cQueue = rb_struct_define_without_accessor_under(
+	rb_cThread,
+	"Queue", rb_cObject, rb_struct_alloc_noinit,
+	"que", "waiters", NULL);
+    rb_cSizedQueue = rb_struct_define_without_accessor_under(
+	rb_cThread,
+	"SizedQueue", rb_cQueue, rb_struct_alloc_noinit,
+	"que", "waiters", "queue_waiters", "size", NULL);
+
+    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, "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");    /* Alias for #push. */
+    rb_define_alias(rb_cQueue, "<<", "push");     /* Alias for #push. */
+    rb_define_alias(rb_cQueue, "deq", "pop");     /* Alias for #pop. */
+    rb_define_alias(rb_cQueue, "shift", "pop");   /* Alias for #pop. */
+    rb_define_alias(rb_cQueue, "size", "length"); /* Alias for #length. */
+
+    rb_define_method(rb_cSizedQueue, "initialize", rb_szqueue_initialize, 1);
+    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, "clear", rb_szqueue_clear, 0);
+    rb_define_method(rb_cSizedQueue, "num_waiting", rb_szqueue_num_waiting, 0);
+
+    rb_define_alias(rb_cSizedQueue, "enq", "push");  /* Alias for #push. */
+    rb_define_alias(rb_cSizedQueue, "<<", "push");   /* Alias for #push. */
+    rb_define_alias(rb_cSizedQueue, "deq", "pop");   /* Alias for #pop. */
+    rb_define_alias(rb_cSizedQueue, "shift", "pop"); /* Alias for #pop. */
+
+    /* CVar */
+    rb_cConditionVariable = rb_struct_define_without_accessor_under(
+	rb_cThread,
+	"ConditionVariable", rb_cObject, rb_struct_alloc_noinit,
+	"waiters", NULL);
+
+    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);
+
+#define ALIAS_GLOBAL_CONST(name) do {	              \
+	ID id = rb_intern_const(#name);	              \
+	if (!rb_const_defined_at(rb_cObject, id)) {   \
+	    rb_const_set(rb_cObject, id, rb_c##name); \
+	}                                             \
+    } while (0)
+
+    ALIAS_GLOBAL_CONST(Mutex);
+    ALIAS_GLOBAL_CONST(Queue);
+    ALIAS_GLOBAL_CONST(SizedQueue);
+    ALIAS_GLOBAL_CONST(ConditionVariable);
+    rb_provide("thread.rb");
+}