Bug 777712 - Adding file descriptors leaks logging on web-workers-shutdown. r=yoric

toolkit/components/osfile/osfile_async_front.jsm

@@ -50,11 +50,12 @@ Components.utils.import("resource://gre/modules/commonjs/sdk/core/promise.js", t
 // The implementation of communications
 Components.utils.import("resource://gre/modules/osfile/_PromiseWorker.jsm", this);
 
+Components.utils.import("resource://gre/modules/Services.jsm", this);
+
 // If profileDir is not available, osfile.jsm has been imported before the
 // profile is setup. In this case, we need to observe "profile-do-change"
 // and set OS.Constants.Path.profileDir as soon as it becomes available.
 if (!("profileDir" in OS.Constants.Path) || !("localProfileDir" in OS.Constants.Path)) {
-  Components.utils.import("resource://gre/modules/Services.jsm", this);
   let observer = function observer() {
     Services.obs.removeObserver(observer, "profile-do-change");
 
@@ -125,6 +126,37 @@ Object.defineProperty(OS.Shared, "DEBUG", {
     }
 });
 
+/**
+ * An observer function to be used to monitor web-workers-shutdown events.
+ */
+let webWorkersShutdownObserver = function webWorkersShutdownObserver() {
+  // Send a "System_shutdown" message to the worker.
+  Scheduler.post("System_shutdown").then(function onSuccess(opened) {
+    let msg = "";
+    if (opened.openedFiles.length > 0) {
+      msg += "The following files are still opened:\n" +
+        opened.openedFiles.join("\n");
+    }
+    if (opened.openedDirectoryIterators.length > 0) {
+      msg += "The following directory iterators are still opened:\n" +
+        opened.openedDirectoryIterators.join("\n");
+    }
+    // Only log if file descriptors leaks detected.
+    if (msg) {
+      LOG("WARNING: File descriptors leaks detected.\n" + msg);
+    }
+  });
+};
+
+// Attaching an observer listening to the "web-workers-shutdown".
+Services.obs.addObserver(webWorkersShutdownObserver, "web-workers-shutdown",
+  false);
+// Attaching the same observer listening to the
+// "test.osfile.web-workers-shutdown".
+// Note: This is used for testing purposes.
+Services.obs.addObserver(webWorkersShutdownObserver,
+  "test.osfile.web-workers-shutdown", false);
+
 /**
  * Representation of a file, with asynchronous methods.
  *

toolkit/components/osfile/osfile_async_worker.js

@@ -114,6 +114,13 @@ if (this.Components) {
          let id = this._idgen++;
          this._map.set(id, {resource:resource, info:info});
          return id;
+       },
+       /**
+        * Return a list of all open resources i.e. the ones still present in
+        * ResourceTracker's _map.
+        */
+       listOpenedResources: function listOpenedResources() {
+         return [resource.info.path for ([id, resource] of this._map)];
        }
      };
 
@@ -193,6 +200,16 @@ if (this.Components) {
        GET_DEBUG: function GET_DEBUG () {
          return exports.OS.Shared.DEBUG;
        },
+       // Report file descriptors leaks.
+       System_shutdown: function System_shutdown () {
+         // Return information about both opened files and opened
+         // directory iterators.
+         return {
+           openedFiles: OpenedFiles.listOpenedResources(),
+           openedDirectoryIterators:
+             OpenedDirectoryIterators.listOpenedResources()
+         };
+       },
        // Functions of OS.File
        stat: function stat(path) {
          return exports.OS.File.Info.toMsg(
@@ -222,8 +239,13 @@ if (this.Components) {
          return File.remove(Type.path.fromMsg(path));
        },
        open: function open(path, mode, options) {
-         let file = File.open(Type.path.fromMsg(path), mode, options);
-         return OpenedFiles.add(file);
+         let filePath = Type.path.fromMsg(path);
+         let file = File.open(filePath, mode, options);
+         return OpenedFiles.add(file, {
+           // Adding path information to keep track of opened files
+           // to report leaks when debugging.
+           path: filePath
+         });
        },
        read: function read(path, bytes) {
          let data = File.read(Type.path.fromMsg(path), bytes);
@@ -242,8 +264,13 @@ if (this.Components) {
                                 );
        },
        new_DirectoryIterator: function new_DirectoryIterator(path, options) {
-         let iterator = new File.DirectoryIterator(Type.path.fromMsg(path), options);
-         return OpenedDirectoryIterators.add(iterator);
+         let directoryPath = Type.path.fromMsg(path);
+         let iterator = new File.DirectoryIterator(directoryPath, options);
+         return OpenedDirectoryIterators.add(iterator, {
+           // Adding path information to keep track of opened directory
+           // iterators to report leaks when debugging.
+           path: directoryPath
+         });
        },
        // Methods of OS.File
        File_prototype_close: function close(fd) {

toolkit/components/osfile/tests/mochi/main_test_osfile_async.js

@@ -141,6 +141,7 @@ let test = maketest("Main", function main(test) {
     yield test_iter();
     yield test_exists();
     yield test_debug_test();
+    yield test_system_shutdown();
     info("Test is over");
     SimpleTest.finish();
   });
@@ -692,3 +693,54 @@ let test_debug_test = maketest("debug_test", function debug_test(test) {
     OS.Shared.DEBUG = originalPref;
   });
 });
+
+/**
+ * Test logging of file descriptors leaks.
+ */
+let test_system_shutdown = maketest("system_shutdown", function system_shutdown(test) {
+  return Task.spawn(function () {
+    // Save original DEBUG value.
+    let originalDebug = OS.Shared.DEBUG;
+    // Create a console listener.
+    function getConsoleListener(resource) {
+      let consoleListener = {
+        observe: function (aMessage) {
+          // Ignore unexpected messages.
+          if (!(aMessage instanceof Components.interfaces.nsIConsoleMessage)) {
+            return;
+          }
+          if (aMessage.message.indexOf("TEST OS Controller WARNING") < 0) {
+            return;
+          }
+          test.ok(aMessage.message.indexOf("WARNING: File descriptors leaks " +
+            "detected.") >= 0, "File descriptors leaks are logged correctly.");
+          test.ok(aMessage.message.indexOf(resource) >= 0,
+            "Leaked resource is correctly listed in the log.");
+          toggleDebugTest(false, resource, consoleListener);
+        }
+      };
+      return consoleListener;
+    }
+    // Set/Unset testing flags and Services.console listener.
+    function toggleDebugTest(startDebug, resource, consoleListener) {
+      Services.console[startDebug ? "registerListener" : "unregisterListener"](
+        consoleListener || getConsoleListener(resource));
+      OS.Shared.TEST = startDebug;
+      // If pref is false, restore DEBUG to its original.
+      OS.Shared.DEBUG = startDebug || originalDebug;
+    }
+
+    let currentDir = yield OS.File.getCurrentDirectory();
+    let iterator = new OS.File.DirectoryIterator(currentDir);
+    toggleDebugTest(true, currentDir);
+    Services.obs.notifyObservers(null, "test.osfile.web-workers-shutdown",
+      null);
+    yield iterator.close();
+
+    let openedFile = yield OS.File.open(EXISTING_FILE);
+    toggleDebugTest(true, EXISTING_FILE);
+    Services.obs.notifyObservers(null, "test.osfile.web-workers-shutdown",
+      null);
+    yield openedFile.close();
+  });
+});