Maintain proper history with roughly six entries, continuously update thumbnails.

guacamole/src/main/webapp/scripts/history.js

@@ -3,8 +3,53 @@
  */
 GuacamoleHistory = new (function() {
 
-    var history =
-        JSON.parse(localStorage.getItem("GUAC_HISTORY") || "{}");
+    /**
+     * Reference to this GuacamoleHistory.
+     */
+    var guac_history = this;
+
+    /**
+     * The number of entries to allow before removing old entries based on the
+     * cutoff.
+     */
+    var IDEAL_LENGTH = 6;
+
+    /**
+     * The maximum age of a history entry before it is removed, in
+     * milliseconds.
+     */
+    var CUTOFF_AGE = 900000;
+
+    var history = {};
+
+    function truncate() {
+
+        // Avoid history growth beyond defined number of entries
+        if (history.length > IDEAL_LENGTH) {
+
+            // Build list of entries
+            var entries = [];
+            for (var old_entry in history)
+                entries.push(old_entry);
+
+            // Sort list
+            entries.sort(GuacamoleHistory.Entries.compare);
+
+            // Remove entries until length is ideal or all are recent
+            var now = new Date().getTime();
+            while (entries.length > IDEAL_LENGTH 
+                    && entries[0].accessed - now > CUTOFF_AGE) {
+
+                // Remove entry
+                var removed = entries.shift();
+                delete history[removed.id];
+
+            }
+
+        }
+
+    }
+
 
     /**
      * Returns the URL for the thumbnail of the connection with the given ID,
@@ -29,12 +74,67 @@ GuacamoleHistory = new (function() {
 
         // Store entry in history
         history[id] = entry;
+        truncate();
 
         // Save updated history
         localStorage.setItem("GUAC_HISTORY", JSON.stringify(history));
 
     };
 
+    /**
+     * Reloads all history data.
+     */
+    this.reload = function() {
+
+        // Get old and new for comparison
+        var old_history = history;
+        var new_history = JSON.parse(localStorage.getItem("GUAC_HISTORY") || "{}");
+
+        // Update history
+        history = new_history;
+
+        // Call onchange handler as necessary
+        if (guac_history.onchange) {
+
+            // Produce union of all known IDs
+            var known_ids = {};
+            for (var new_id in new_history) known_ids[new_id] = true;
+            for (var old_id in old_history) known_ids[old_id] = true;
+
+            // For each known ID
+            for (var id in known_ids) {
+
+                // Get entries
+                var old_entry = old_history[id];    
+                var new_entry = new_history[id];    
+
+                // Call handler for all changed 
+                if (!old_entry || !new_entry
+                        || old_entry.accessed != new_entry.accessed)
+                    guac_history.onchange(id, old_entry, new_entry);
+
+            }
+
+        } // end onchange
+
+    };
+
+    /**
+     * Event handler called whenever a history entry is changed.
+     * 
+     * @event
+     * @param {String} id The ID of the connection whose history entry is
+     *                    changing.
+     * @param {GuacamoleHistory.Entry} old_entry The old value of the entry, if
+     *                                           any.
+     * @param {GuacamoleHistory.Entry} new_entry The new value of the entry, if
+     *                                           any.
+     */
+    this.onchange = null;
+
+    // Initial load
+    guac_history.reload();
+
 })();
 
 /**
@@ -66,4 +166,7 @@ GuacamoleHistory.Entry = function(id, thumbnail, last_access) {
     this.accessed = last_access;
 
 };
- 
+ 
+GuacamoleHistory.Entry.compare = function(a, b) {
+    return a.accessed - b.accessed;
+};