Implemented Guacamole.Parser

guacamole-common-js/src/main/resources/guacamole.js

@@ -42,6 +42,131 @@
  */
 var Guacamole = Guacamole || {};
 
+/**
+ * Simple Guacamole protocol parser that invokes an oninstruction event when
+ * full instructions are available from data received via receive().
+ * 
+ * @constructor
+ */
+Guacamole.Parser = function() {
+
+    /**
+     * Reference to this parser.
+     * @private
+     */
+    var parser = this;
+
+    /**
+     * Current buffer of received data. This buffer grows until a full
+     * element is available. After a full element is available, that element
+     * is flushed into the element buffer.
+     * 
+     * @priate
+     */
+    var buffer = "";
+
+    /**
+     * Buffer of all received, complete elements. After an entire instruction
+     * is read, this buffer is flushed, and a new instruction begins.
+     * 
+     * @priate
+     */
+    var element_buffer = [];
+
+    // The location of the last element's terminator
+    var element_end = -1;
+
+    // Where to start the next length search or the next element
+    var start_index = 0;
+
+    this.receive = function(packet) {
+
+        // Truncate buffer as necessary
+        if (start_index > 4096) {
+
+            buffer = buffer.substring(start_index);
+
+            // Reset parse relative to truncation
+            element_end -= start_index;
+            start_index = 0;
+
+        }
+
+        // Append data to buffer
+        buffer += packet;
+
+        // While search is within currently received data
+        while (element_end < buffer.length) {
+
+            // If we are waiting for element data
+            if (element_end >= start_index) {
+
+                // We now have enough data for the element. Parse.
+                var element = buffer.substring(start_index, element_end);
+                var terminator = buffer.substring(element_end, element_end+1);
+
+                // Add element to array
+                element_buffer.push(element);
+
+                // If last element, handle instruction
+                if (terminator == ";") {
+
+                    // Get opcode
+                    var opcode = element_buffer.shift();
+
+                    // Call instruction handler.
+                    if (parser.oninstruction != null)
+                        parser.oninstruction(opcode, element_buffer);
+
+                    // Clear elements
+                    element_buffer.length = 0;
+
+                }
+
+                // Start searching for length at character after
+                // element terminator
+                start_index = element_end + 1;
+
+            }
+
+            // Search for end of length
+            var length_end = buffer.indexOf(".", start_index);
+            if (length_end != -1) {
+
+                // Parse length
+                var length = parseInt(buffer.substring(element_end+1, length_end));
+
+                // Calculate start of element
+                start_index = length_end + 1;
+
+                // Calculate location of element terminator
+                element_end = start_index + length;
+
+            }
+            
+            // If no period yet, continue search when more data
+            // is received
+            else {
+                start_index = buffer.length;
+                break;
+            }
+
+        } // end parse loop
+
+    };
+
+    /**
+     * Fired once for every complete Guacamole instruction received, in order.
+     * 
+     * @event
+     * @param {String} opcode The Guacamole instruction opcode.
+     * @param {Array} parameters The parameters provided for the instruction,
+     *                           if any.
+     */
+    this.oninstruction = null;
+
+};
+
 
 /**
  * Guacamole protocol client. Given a display element and {@link Guacamole.Tunnel},