[java] Mutex implementation

std/java/vm/Mutex.hx

@@ -0,0 +1,82 @@
+package java.vm;
+
+@:native('haxe.java.vm.Mutex') class Mutex
+{
+	@:private var owner:java.lang.Thread;
+	@:private var lockCount:Int = 0;
+
+	/**
+		Creates a mutex, which can be used to acquire a temporary lock to access some resource.
+		The main difference with a lock is that a mutex must always be released by the owner thread
+	**/
+	public function new()
+	{
+
+	}
+
+	/**
+		Try to acquire the mutex, returns true if acquire or false if it's already locked by another thread.
+	**/
+	public function tryAcquire():Bool
+	{
+		var ret = false, cur = java.lang.Thread.currentThread();
+		untyped __lock__(this, {
+			var expr = null;
+			if (owner == null)
+			{
+				ret = true;
+				if(lockCount != 0) throw "assert";
+				lockCount = 1;
+				owner = cur;
+			} else if (owner == cur) {
+				ret = true;
+				owner = cur;
+				lockCount++;
+			}
+		});
+		return ret;
+	}
+
+	/**
+		The current thread acquire the mutex or wait if not available.
+		The same thread can acquire several times the same mutex, but must release it as many times it has been acquired.
+	**/
+	public function acquire():Void
+	{
+		var cur = java.lang.Thread.currentThread();
+		untyped __lock__(this, {
+			var expr = null;
+			if (owner == null)
+			{
+				owner = cur;
+				if (lockCount != 0) throw "assert";
+				lockCount = 1;
+			} else if (owner == cur) {
+				lockCount++;
+			} else {
+				try { untyped this.wait(); } catch(e:Dynamic) { throw e; }
+				lockCount = 1;
+				owner = cur;
+			}
+		});
+	}
+
+	/**
+		Release a mutex that has been acquired by the current thread. If the current thread does not own the mutex, an exception will be thrown
+	**/
+	public function release():Void
+	{
+		var cur = java.lang.Thread.currentThread();
+		untyped __lock__(this, {
+			var expr = null;
+			if (owner != cur) {
+				throw "This mutex isn't owned by the current thread!";
+			}
+			if (--lockCount == 0)
+			{
+				this.owner = null;
+				untyped this.notify();
+			}
+		});
+	}
+}