Merge branch 'master' of git@github.com:ether/pad

1 files changed, 81 insertions, 0 deletions

diff --git a/infrastructure/framework-src/modules/sync.js b/infrastructure/framework-src/modules/sync.js
new file mode 100644
index 0000000..a222ea0
--- /dev/null
+++ b/infrastructure/framework-src/modules/sync.js
@@ -0,0 +1,81 @@
+/**
+ * Copyright 2009 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS-IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+jimport("java.util.concurrent.locks.ReentrantLock");
+jimport("net.appjet.oui.GlobalSynchronizer");
+
+/**
+ * synchronously calls a no-argument function.
+ * f may have return values.
+ */
+function callsync(obj, f) {
+  if (!obj._LOCK) {
+    try {
+      appjet.globalLock.lock();
+      if (! obj._LOCK) {
+        obj._LOCK = new ReentrantLock();
+      }
+    } finally {
+      appjet.globalLock.unlock();
+    }
+  }
+  try {
+    obj._LOCK.lock();
+    return f();
+  } finally {
+    obj._LOCK.unlock();
+  }
+}
+
+/** 
+ * synchronously calls a no-argument function iff
+ * condition() is true. condition may be called 
+ * twice and shouldn't have side-effects.
+ */
+function callsyncIfTrue(obj, condition, f) {
+  if (condition()) {
+    callsync(obj, function() {
+      if (condition()) {
+        f();
+      }
+    });
+  }
+}
+
+/**
+ * returns a function that synchronously calls
+ * f with its own arguments
+ */
+function wrapsync(obj, f, thisArg) {
+  return function() {
+    var args = Array.prototype.slice.call(arguments);
+    var wrapper = function() {
+      return f.apply(thisArg, args);
+    }
+    callsync(obj, wrapper);
+  }
+}
+
+function doWithStringLock(lockName, fn) {
+  GlobalSynchronizer.acquire(lockName);
+  try {
+    return fn();
+  }
+  finally {
+    GlobalSynchronizer.release(lockName);
+  }
+}
+