Update TV Source to find media files

Updated TV Source to iterate over media files and check each against the
cache to ignore previously seen items.

source/lib/DownloadDispatcher/Source/PluginBase.class.php

@@ -0,0 +1,32 @@
+<?php
+
+class DownloadDispatcher_Source_PluginBase extends DownloadDispatcher_PluginBase {
+    
+    static protected $source_cache = array();
+    
+    protected function init_cache() {
+        if ( ! array_key_exists(get_called_class(), static::$source_cache)) {
+            // TODO - attempt to load data from persistent storage
+            static::$source_cache[get_called_class()] = array();
+        } 
+    }
+    
+    protected function mark_processed($file) {
+        $this->init_cache();
+        
+        if ( ! in_array($file, static::$source_cache[get_called_class()])) {
+            static::$source_cache[get_called_class()][] = $file;
+        }
+        
+        // TODO - flush cache to persistent storage
+    }
+    
+    protected function check_processed($file) {
+        $this->init_cache();
+        
+        return in_array($file, static::$source_cache[get_called_class()]);
+    }
+    
+}
+
+?>