svn commit: r1049773 - /shindig/trunk/features/src/main/javascript/features/rpc/flash.transport.js

[jo...@apache.org]

Author: johnh
Date: Thu Dec 16 03:21:22 2010
New Revision: 1049773

URL: http://svn.apache.org/viewvc?rev=1049773&view=rev
Log:
Beginning of transport for Flash-type transport. Not integrated w/ rpc.js at all, and code builds, so committing early for comment and iteration.


Added:
    shindig/trunk/features/src/main/javascript/features/rpc/flash.transport.js

Added: shindig/trunk/features/src/main/javascript/features/rpc/flash.transport.js
URL: http://svn.apache.org/viewvc/shindig/trunk/features/src/main/javascript/features/rpc/flash.transport.js?rev=1049773&view=auto
==============================================================================
--- shindig/trunk/features/src/main/javascript/features/rpc/flash.transport.js (added)
+++ shindig/trunk/features/src/main/javascript/features/rpc/flash.transport.js Thu Dec 16 03:21:22 2010
@@ -0,0 +1,116 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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.
+ */
+
+gadgets.rpctx = gadgets.rpctx || {};
+
+/**
+ * Transport for browsers that utilizes a small Flash bridge and
+ * Flash's ExternalInterface methods to transport messages securely,
+ * and with guarantees provided on sender identity. This largely emulates wpm.
+ *
+ *   flash: postMessage on the window object.
+ *        - Internet Explorer 6/7
+ *        - In theory, any browser supporting Flash 8 and above,
+ *          though embed code is tailored to IE only to reduce size.
+ *        + (window.postMessage takes precedence where available)
+ */
+if (!gadgets.rpctx.wpm) {  // make lib resilient to double-inclusion
+
+  gadgets.rpctx.flash = function() {
+    var swfUrl = "//flashrpctx.googleusercontent.com/xpc.swf";
+    var process = null;
+    var ready = null;
+    var relayHandle = null;
+
+    var LOADER_TIMEOUT_MS = 100;
+    var MAX_LOADER_RETRIES = 100;
+    var pendingHandshakes = [];
+    var setupHandle = null;
+    var setupAttempts = 0;
+
+    function handshakePoller() {
+      if (relayHandle === null && document.body) {
+        relayHandle = document.createElement('embed');
+        relayHandle.allowScriptAccess = true;
+        relayHandle.src = swfUrl + '?origin=' + window.location;
+        document.body.appendChild(relayHandle);
+      }
+      ++setupAttempts;
+      if (setupHandle !== null &&
+          (relayHandle !== null || setupAttempts >= MAX_LOADER_RETRIES)) {
+        window.clearTimeout(setupHandle);
+      }
+    }
+
+    function flushHandshakes() {
+      if (relayHandle !== null) {
+        while (pendingHandshakes.length > 0) {
+          var shake = pendingHandshakes.shift();
+          relayHandle.setup(shake.id, shake.role);
+        }
+      }
+    }
+
+    return {
+      getCode: function() {
+        return 'flash';
+      },
+
+      isParentVerifiable: function() {
+        return true;
+      },
+
+      init: function(processFn, readyFn) {
+        process = processFn;
+        ready = readyFn;
+        return true;
+      },
+
+      setup: function(receiverId, token) {
+        // Perform all setup, including embedding of relay SWF (a one-time
+        // per Window operation), in this method. We cannot assume document.body
+        // exists however, since child-to-parent setup is often done in head.
+        // Thus we simply enqueue a setup pair and attempt to complete them all.
+        // If body already exists then this enqueueing will immediately flush;
+        // otherwise polling will occur until the SWF has completed loading, at
+        // which point all connections will complete their handshake.
+        var role = targetId === ".." ? "OUTER" : "INNER";
+        pendingHandshakes.push({ id: targetId, role: role });
+        if (relayHandle === null && setupHandle === null) {
+          setupHandle = window.setTimeout(relayLoader, LOADER_TIMEOUT_MS);
+        }
+        flushHandshakes();
+        return true;
+      },
+
+      call: function(targetId, from, rpc) {
+        return true;
+      },
+
+      // Methods called by relay SWF. Should be considered private.
+      _receiveMessage: function(channel, message, from, to) {
+      },
+
+      _ready: function() {
+        flushHandshakes();
+        setupHandle = null;
+      }
+    };
+  }();
+
+} // !end of double-inclusion guard