POSIX threads corrections & enhancements

spec/std/thread/condition_variable_spec.cr

@@ -1,90 +1,89 @@
 require "spec"
 
-# These specs are marked as pending until we add
-# support for parallelism, where we'll see if we
-# need condition variables.
-#
-# Also: review these specs!
 describe Thread::ConditionVariable do
-  pending "signals" do
+  it "signals" do
     mutex = Thread::Mutex.new
     cond = Thread::ConditionVariable.new
-    pcond = Thread::ConditionVariable.new
-    waiting = 0
-    signaled = 0
 
-    threads = 3.times.map do
+    mutex.synchronize do
       Thread.new do
-        mutex.synchronize do
-          waiting += 1
-          # TODO: why is this needed? Bug?
-          pcond.signal
-          cond.wait mutex
-        end
+        mutex.synchronize { cond.signal }
       end
-    end.to_a
 
-    while signaled < 3
-      mutex.synchronize do
-        if waiting > 0
-          waiting -= 1
-          signaled += 1
-          cond.signal
-        end
-      end
+      cond.wait(mutex)
     end
-    threads.map &.join
   end
 
-  pending "broadcasts" do
+  it "signals & broadcasts" do
     mutex = Thread::Mutex.new
-    cond = Thread::ConditionVariable.new
-    pcond = Thread::ConditionVariable.new
+    cv1 = Thread::ConditionVariable.new
+    cv2 = Thread::ConditionVariable.new
     waiting = 0
-    signaled = false
 
-    threads = 3.times.map do
+    5.times do
       Thread.new do
         mutex.synchronize do
           waiting += 1
-          pcond.signal
-          cond.wait mutex
+          cv1.wait(mutex)
+
+          waiting -= 1
+          cv2.signal
         end
       end
-    end.to_a
-
-    until signaled
-      mutex.synchronize do
-        if waiting >= 3
-          cond.broadcast
-          signaled = true
-        else
-          pcond.wait mutex
-        end
+    end
+
+    # wait for all threads to have acquired the mutex and be waiting on the
+    # condition variable, otherwise the main thread could acquire the lock
+    # first, and signal into the void.
+    #
+    # since increments to waiting are synchronized, at least 4 threads are
+    # guaranteed to be waiting when waiting is 5, which is enough for futher
+    # tests to never hangup.
+    until waiting == 5
+      Thread.yield
+    end
+
+    # wakes up at least 1 thread:
+    mutex.synchronize do
+      cv1.signal
+      cv2.wait(mutex)
+    end
+    waiting.should be < 5
+
+    # wakes up all waiting threads:
+    mutex.synchronize do
+      cv1.broadcast
+
+      until waiting == 0
+        cv2.wait(mutex, 1.second) { raise "unexpected wait timeout" }
       end
     end
+  end
+
+  it "timeouts" do
+    timedout = false
+    mutex = Thread::Mutex.new
+    cond = Thread::ConditionVariable.new
 
-    threads.map &.join
+    mutex.synchronize do
+      cond.wait(mutex, 1.microsecond) { timedout = true }
+    end
+    timedout.should be_true
   end
 
-  pending "waits and send signal" do
-    a = 0
-    cv1 = Thread::ConditionVariable.new
-    cv2 = Thread::ConditionVariable.new
-    m = Thread::Mutex.new
+  it "resumes before timeout" do
+    timedout = false
+    mutex = Thread::Mutex.new
+    cond = Thread::ConditionVariable.new
 
-    thread = Thread.new do
-      3.times do
-        m.synchronize { cv1.wait(m); a += 1; cv2.signal }
+    mutex.synchronize do
+      Thread.new do
+        mutex.synchronize { cond.signal }
       end
-    end
 
-    a.should eq(0)
-    3.times do |i|
-      m.synchronize { cv1.signal; cv2.wait(m) }
-      a.should eq(i + 1)
+      cond.wait(mutex, 1.second) { timedout = true }
     end
 
-    thread.join
+    timedout.should be_false
   end
 end

spec/std/thread/mutex_spec.cr

@@ -0,0 +1,36 @@
+require "spec"
+
+describe Thread::Mutex do
+  it "synchronizes" do
+    a = 0
+    mutex = Thread::Mutex.new
+
+    threads = 10.times.map do
+      Thread.new do
+        mutex.synchronize { a += 1 }
+      end
+    end.to_a
+
+    threads.each(&.join)
+    a.should eq(10)
+  end
+
+  it "won't lock recursively" do
+    mutex = Thread::Mutex.new
+    mutex.try_lock.should be_true
+    mutex.try_lock.should be_false
+    expect_raises(Errno) { mutex.lock }
+    mutex.unlock
+  end
+
+  it "won't unlock from another thread" do
+    mutex = Thread::Mutex.new
+    mutex.lock
+
+    expect_raises(Errno) do
+      Thread.new { mutex.unlock }.join
+    end
+
+    mutex.unlock
+  end
+end

spec/std/thread_spec.cr

@@ -14,4 +14,27 @@ describe Thread do
       thread.join
     end
   end
+
+  it "returns current thread object" do
+    current = nil
+    thread = Thread.new { current = Thread.current }
+    thread.join
+    current.should be(thread)
+    current.should_not be(Thread.current)
+  end
+
+  it "yields the processor" do
+    done = false
+
+    thread = Thread.new do
+      3.times { Thread.yield }
+      done = true
+    end
+
+    until done
+      Thread.yield
+    end
+
+    thread.join
+  end
 end

src/gc/boehm.cr

@@ -162,7 +162,7 @@ module GC
     # :nodoc:
     def self.pthread_join(thread : LibC::PthreadT) : Void*
       ret = LibGC.pthread_join(thread, out value)
-      raise Errno.new("pthread_join") unless ret == 0
+      raise Errno.new("pthread_join", ret) unless ret == 0
       value
     end
 

src/lib_c/aarch64-linux-gnu/c/pthread.cr

@@ -1,15 +1,24 @@
 require "./sys/types"
 
 lib LibC
+  PTHREAD_MUTEX_ERRORCHECK = 2
+
+  fun pthread_condattr_destroy(attr : PthreadCondattrT*) : Int
+  fun pthread_condattr_init(attr : PthreadCondattrT*) : Int
+  fun pthread_condattr_setclock(attr : PthreadCondattrT*, type : ClockidT) : Int
   fun pthread_cond_broadcast(cond : PthreadCondT*) : Int
   fun pthread_cond_destroy(cond : PthreadCondT*) : Int
   fun pthread_cond_init(cond : PthreadCondT*, cond_attr : PthreadCondattrT*) : Int
   fun pthread_cond_signal(cond : PthreadCondT*) : Int
+  fun pthread_cond_timedwait(cond : PthreadCondT*, mutex : PthreadMutexT*, abstime : Timespec*) : Int
   fun pthread_cond_wait(cond : PthreadCondT*, mutex : PthreadMutexT*) : Int
   fun pthread_create(newthread : PthreadT*, attr : PthreadAttrT*, start_routine : Void* -> Void*, arg : Void*) : Int
   fun pthread_detach(th : PthreadT) : Int
   fun pthread_equal(thread1 : PthreadT, thread2 : PthreadT) : Int
   fun pthread_join(th : PthreadT, thread_return : Void**) : Int
+  fun pthread_mutexattr_destroy(attr : PthreadMutexattrT*) : Int
+  fun pthread_mutexattr_init(attr : PthreadMutexattrT*) : Int
+  fun pthread_mutexattr_settype(attr : PthreadMutexattrT*, type : Int) : Int
   fun pthread_mutex_destroy(mutex : PthreadMutexT*) : Int
   fun pthread_mutex_init(mutex : PthreadMutexT*, mutexattr : PthreadMutexattrT*) : Int
   fun pthread_mutex_lock(mutex : PthreadMutexT*) : Int

src/lib_c/aarch64-linux-gnu/c/sched.cr

@@ -0,0 +1,3 @@
+lib LibC
+  fun sched_yield : Int
+end

src/lib_c/aarch64-linux-musl/c/pthread.cr

@@ -1,14 +1,23 @@
 require "./sys/types"
 
 lib LibC
+  PTHREAD_MUTEX_ERRORCHECK = 2
+
+  fun pthread_condattr_destroy(x0 : PthreadCondattrT*) : Int
+  fun pthread_condattr_init(x0 : PthreadCondattrT*) : Int
+  fun pthread_condattr_setclock(x0 : PthreadCondattrT*, x1 : ClockidT) : Int
   fun pthread_cond_broadcast(x0 : PthreadCondT*) : Int
   fun pthread_cond_destroy(x0 : PthreadCondT*) : Int
   fun pthread_cond_init(x0 : PthreadCondT*, x1 : PthreadCondattrT*) : Int
   fun pthread_cond_signal(x0 : PthreadCondT*) : Int
+  fun pthread_cond_timedwait(x0 : PthreadCondT*, x1 : PthreadMutexT*, x2 : Timespec*) : Int
   fun pthread_cond_wait(x0 : PthreadCondT*, x1 : PthreadMutexT*) : Int
   fun pthread_create(x0 : PthreadT*, x1 : PthreadAttrT*, x2 : Void* -> Void*, x3 : Void*) : Int
   fun pthread_detach(x0 : PthreadT) : Int
   fun pthread_join(x0 : PthreadT, x1 : Void**) : Int
+  fun pthread_mutexattr_destroy(x0 : PthreadMutexattrT*) : Int
+  fun pthread_mutexattr_init(x0 : PthreadMutexattrT*) : Int
+  fun pthread_mutexattr_settype(x0 : PthreadMutexattrT*, x1 : Int) : Int
   fun pthread_mutex_destroy(x0 : PthreadMutexT*) : Int
   fun pthread_mutex_init(x0 : PthreadMutexT*, x1 : PthreadMutexattrT*) : Int
   fun pthread_mutex_lock(x0 : PthreadMutexT*) : Int

src/lib_c/aarch64-linux-musl/c/sched.cr

@@ -0,0 +1,3 @@
+lib LibC
+  fun sched_yield : Int
+end

src/lib_c/amd64-unknown-openbsd/c/pthread.cr

@@ -2,10 +2,16 @@ require "./sys/types"
 
 @[Link("pthread")]
 lib LibC
+  PTHREAD_MUTEX_ERRORCHECK = 1
+
+  fun pthread_condattr_destroy(x0 : PthreadCondattrT*) : Int
+  fun pthread_condattr_init(x0 : PthreadCondattrT*) : Int
+  fun pthread_condattr_setclock(x0 : PthreadCondattrT*, x1 : ClockidT) : Int
   fun pthread_cond_broadcast(x0 : PthreadCondT*) : Int
   fun pthread_cond_destroy(x0 : PthreadCondT*) : Int
   fun pthread_cond_init(x0 : PthreadCondT*, x1 : PthreadCondattrT*) : Int
   fun pthread_cond_signal(x0 : PthreadCondT*) : Int
+  fun pthread_cond_timedwait(x0 : PthreadCondT*, x1 : PthreadMutexT*, x2 : Timespec*) : Int
   fun pthread_cond_wait(x0 : PthreadCondT*, x1 : PthreadMutexT*) : Int
   fun pthread_create(x0 : PthreadT*, x1 : PthreadAttrT*, x2 : Void* -> Void*, x3 : Void*) : Int
   fun pthread_detach(x0 : PthreadT) : Int
@@ -14,6 +20,9 @@ lib LibC
   fun pthread_join(x0 : PthreadT, x1 : Void**) : Int
   alias PthreadKeyDestructor = (Void*) ->
   fun pthread_key_create(PthreadKeyT*, PthreadKeyDestructor) : Int
+  fun pthread_mutexattr_destroy(x0 : PthreadMutexattrT*) : Int
+  fun pthread_mutexattr_init(x0 : PthreadMutexattrT*) : Int
+  fun pthread_mutexattr_settype(x0 : PthreadMutexattrT*, x1 : Int) : Int
   fun pthread_mutex_destroy(x0 : PthreadMutexT*) : Int
   fun pthread_mutex_init(x0 : PthreadMutexT*, x1 : PthreadMutexattrT*) : Int
   fun pthread_mutex_lock(x0 : PthreadMutexT*) : Int

src/lib_c/amd64-unknown-openbsd/c/sched.cr

@@ -0,0 +1,3 @@
+lib LibC
+  fun sched_yield : Int
+end

src/lib_c/arm-linux-gnueabihf/c/pthread.cr

@@ -1,15 +1,24 @@
 require "./sys/types"
 
 lib LibC
+  PTHREAD_MUTEX_ERRORCHECK = 2
+
+  fun pthread_condattr_destroy(attr : PthreadCondattrT*) : Int
+  fun pthread_condattr_init(attr : PthreadCondattrT*) : Int
+  fun pthread_condattr_setclock(attr : PthreadCondattrT*, type : ClockidT) : Int
   fun pthread_cond_broadcast(cond : PthreadCondT*) : Int
   fun pthread_cond_destroy(cond : PthreadCondT*) : Int
   fun pthread_cond_init(cond : PthreadCondT*, cond_attr : PthreadCondattrT*) : Int
   fun pthread_cond_signal(cond : PthreadCondT*) : Int
+  fun pthread_cond_timedwait(cond : PthreadCondT*, mutex : PthreadMutexT*, abstime : Timespec*) : Int
   fun pthread_cond_wait(cond : PthreadCondT*, mutex : PthreadMutexT*) : Int
   fun pthread_create(newthread : PthreadT*, attr : PthreadAttrT*, start_routine : Void* -> Void*, arg : Void*) : Int
   fun pthread_detach(th : PthreadT) : Int
   fun pthread_equal(thread1 : PthreadT, thread2 : PthreadT) : Int
   fun pthread_join(th : PthreadT, thread_return : Void**) : Int
+  fun pthread_mutexattr_destroy(attr : PthreadMutexattrT*) : Int
+  fun pthread_mutexattr_init(attr : PthreadMutexattrT*) : Int
+  fun pthread_mutexattr_settype(attr : PthreadMutexattrT*, type : Int) : Int
   fun pthread_mutex_destroy(mutex : PthreadMutexT*) : Int
   fun pthread_mutex_init(mutex : PthreadMutexT*, mutexattr : PthreadMutexattrT*) : Int
   fun pthread_mutex_lock(mutex : PthreadMutexT*) : Int

src/lib_c/arm-linux-gnueabihf/c/sched.cr

@@ -0,0 +1,3 @@
+lib LibC
+  fun sched_yield : Int
+end

src/lib_c/i686-linux-gnu/c/pthread.cr

@@ -1,14 +1,23 @@
 require "./sys/types"
 
 lib LibC
+  PTHREAD_MUTEX_ERRORCHECK = 2
+
+  fun pthread_condattr_destroy(attr : PthreadCondattrT*) : Int
+  fun pthread_condattr_init(attr : PthreadCondattrT*) : Int
+  fun pthread_condattr_setclock(attr : PthreadCondattrT*, type : ClockidT) : Int
   fun pthread_cond_broadcast(cond : PthreadCondT*) : Int
   fun pthread_cond_destroy(cond : PthreadCondT*) : Int
   fun pthread_cond_init(cond : PthreadCondT*, cond_attr : PthreadCondattrT*) : Int
   fun pthread_cond_signal(cond : PthreadCondT*) : Int
+  fun pthread_cond_timedwait(cond : PthreadCondT*, mutex : PthreadMutexT*, abstime : Timespec*) : Int
   fun pthread_cond_wait(cond : PthreadCondT*, mutex : PthreadMutexT*) : Int
   fun pthread_create(newthread : PthreadT*, attr : PthreadAttrT*, start_routine : Void* -> Void*, arg : Void*) : Int
   fun pthread_detach(th : PthreadT) : Int
   fun pthread_join(th : PthreadT, thread_return : Void**) : Int
+  fun pthread_mutexattr_destroy(attr : PthreadMutexattrT*) : Int
+  fun pthread_mutexattr_init(attr : PthreadMutexattrT*) : Int
+  fun pthread_mutexattr_settype(attr : PthreadMutexattrT*, type : Int) : Int
   fun pthread_mutex_destroy(mutex : PthreadMutexT*) : Int
   fun pthread_mutex_init(mutex : PthreadMutexT*, mutexattr : PthreadMutexattrT*) : Int
   fun pthread_mutex_lock(mutex : PthreadMutexT*) : Int

src/lib_c/i686-linux-gnu/c/sched.cr

@@ -0,0 +1,3 @@
+lib LibC
+  fun sched_yield : Int
+end

src/lib_c/i686-linux-musl/c/pthread.cr

@@ -1,14 +1,23 @@
 require "./sys/types"
 
 lib LibC
+  PTHREAD_MUTEX_ERRORCHECK = 2
+
+  fun pthread_condattr_destroy(x0 : PthreadCondattrT*) : Int
+  fun pthread_condattr_init(x0 : PthreadCondattrT*) : Int
+  fun pthread_condattr_setclock(x0 : PthreadCondattrT*, x1 : ClockidT) : Int
   fun pthread_cond_broadcast(x0 : PthreadCondT*) : Int
   fun pthread_cond_destroy(x0 : PthreadCondT*) : Int
   fun pthread_cond_init(x0 : PthreadCondT*, x1 : PthreadCondattrT*) : Int
   fun pthread_cond_signal(x0 : PthreadCondT*) : Int
+  fun pthread_cond_timedwait(x0 : PthreadCondT*, x1 : PthreadMutexT*, x2 : Timespec*) : Int
   fun pthread_cond_wait(x0 : PthreadCondT*, x1 : PthreadMutexT*) : Int
   fun pthread_create(x0 : PthreadT*, x1 : PthreadAttrT*, x2 : Void* -> Void*, x3 : Void*) : Int
   fun pthread_detach(x0 : PthreadT) : Int
   fun pthread_join(x0 : PthreadT, x1 : Void**) : Int
+  fun pthread_mutexattr_destroy(x0 : PthreadMutexattrT*) : Int
+  fun pthread_mutexattr_init(x0 : PthreadMutexattrT*) : Int
+  fun pthread_mutexattr_settype(x0 : PthreadMutexattrT*, x1 : Int) : Int
   fun pthread_mutex_destroy(x0 : PthreadMutexT*) : Int
   fun pthread_mutex_init(x0 : PthreadMutexT*, x1 : PthreadMutexattrT*) : Int
   fun pthread_mutex_lock(x0 : PthreadMutexT*) : Int

src/lib_c/i686-linux-musl/c/sched.cr

@@ -0,0 +1,3 @@
+lib LibC
+  fun sched_yield : Int
+end