Update pthreads example

examples/pthread/pthread.tm

@@ -1,13 +1,8 @@
+# A Posix Threads (pthreads) wrapper
 use <pthread.h>
 
-struct pthread_cond_t(; extern, opaque):
-    func new(->@pthread_cond_t):
-        return inline C : @pthread_cond_t {
-            pthread_cond_t *cond = new(pthread_cond_t);
-            pthread_cond_init(cond, NULL);
-            GC_register_finalizer(cond, (void*)pthread_cond_destroy, NULL, NULL, NULL);
-            cond
-        }
+extern pthread_mutex_lock:func(mutex:&pthread_mutex_t -> Int32)
+extern pthread_mutex_unlock:func(mutex:&pthread_mutex_t -> Int32)
 
 struct pthread_mutex_t(; extern, opaque):
     func new(->@pthread_mutex_t):
@@ -18,15 +13,33 @@ struct pthread_mutex_t(; extern, opaque):
             mutex
         }
 
+    func lock(m:&pthread_mutex_t):
+        fail("Failed to lock mutex") unless pthread_mutex_lock(m) == 0
+
+    func unlock(m:&pthread_mutex_t):
+        fail("Failed to unlock mutex") unless pthread_mutex_unlock(m) == 0
+
 extern pthread_cond_wait:func(cond:&pthread_cond_t, mutex:&pthread_mutex_t -> Int32)
 extern pthread_cond_signal:func(cond:&pthread_cond_t -> Int32)
 extern pthread_cond_broadcast:func(cond:&pthread_cond_t -> Int32)
-extern pthread_mutex_lock:func(mutex:&pthread_mutex_t -> Int32)
-extern pthread_mutex_unlock:func(mutex:&pthread_mutex_t -> Int32)
 
-# extern pthread_join:func(thread:pthread_t, retval=none:@@Memory)
-# extern pthread_cancel:func(thread:pthread_t)
-# extern pthread_detach:func(thread:pthread_t)
+struct pthread_cond_t(; extern, opaque):
+    func new(->@pthread_cond_t):
+        return inline C : @pthread_cond_t {
+            pthread_cond_t *cond = new(pthread_cond_t);
+            pthread_cond_init(cond, NULL);
+            GC_register_finalizer(cond, (void*)pthread_cond_destroy, NULL, NULL, NULL);
+            cond
+        }
+
+    func wait(cond:&pthread_cond_t, mutex:&pthread_mutex_t):
+        fail("Failed to wait on condition") unless pthread_cond_wait(cond, mutex) == 0
+
+    func signal(cond:&pthread_cond_t):
+        fail("Failed to signal pthread_cond_t") unless pthread_cond_signal(cond) == 0
+
+    func broadcast(cond:&pthread_cond_t):
+        fail("Failed to broadcast pthread_cond_t") unless pthread_cond_broadcast(cond) == 0
 
 struct pthread_t(; extern, opaque):
     func new(fn:func() -> @pthread_t):
@@ -39,3 +52,56 @@ struct pthread_t(; extern, opaque):
     func join(p:@pthread_t): inline C { pthread_join(*_$p, NULL); }
     func cancel(p:@pthread_t): inline C { pthread_cancel(*_$p); }
     func detatch(p:@pthread_t): inline C { pthread_detach(*_$p); }
+
+struct IntQueue(_queue:@[Int], _mutex:@pthread_mutex_t, _cond:@pthread_cond_t):
+    func new(initial=[:Int] -> IntQueue):
+        return IntQueue(@initial, pthread_mutex_t.new(), pthread_cond_t.new())
+
+    func give(q:IntQueue, n:Int):
+        begin: q._mutex:lock()
+        end: q._mutex:unlock()
+        do: q._queue:insert(n)
+        q._cond:signal()
+
+    func take(q:IntQueue -> Int):
+        begin: q._mutex:lock()
+        end: q._mutex:unlock()
+        do:
+            repeat:
+                if n := q._queue:pop(1):
+                    return n
+                q._cond:wait(q._mutex)
+        fail("Unreachable")
+
+func main():
+    jobs := IntQueue.new()
+    results := IntQueue.new()
+
+    say_mutex := pthread_mutex_t.new()
+    announce := func(speaker:Text, text:Text):
+        begin: say_mutex:lock()
+        end: say_mutex:unlock()
+        do: say("$\033[2m[$speaker]$\033[m $text")
+
+    worker := pthread_t.new(func():
+        say("I'm in the thread!")
+        repeat:
+            announce("worker", "waiting for job")
+            job := jobs:take()
+            result := job * 10
+            announce("worker", "Jobbing $job into $result")
+            results:give(result)
+            announce("worker", "Signaled $result")
+    )
+
+    for i in 10:
+        announce("boss", "Pushing job $i")
+        jobs:give(i)
+        announce("boss", "Gave job $i")
+
+    for i in 10:
+        announce("boss", "Getting result...")
+        result := results:take()
+        announce("boss", "Got result $result")
+
+    >> worker:cancel()