adding CCache to improve cache handling of dummy and srgb

CCache.php

@@ -0,0 +1,107 @@
+<?php
+/**
+ * Deal with the cache directory and cached items.
+ *
+ */
+class CCache
+{
+    /**
+     * Path to the cache directory.
+     */
+    private $path;
+
+
+
+    /**
+     * Set the path to the cache dir which must exist.
+     *
+     * @param string path to the cache dir.
+     *
+     * @throws Exception when $path is not a directory.
+     *
+     * @return $this
+     */
+    public function setDir($path)
+    {
+        if (!is_dir($path)) {
+            throw new Exception("Cachedir is not a directory.");
+        }
+
+        $this->path = $path;
+
+        return $this;
+    }
+
+
+
+    /**
+     * Get the path to the cache subdir and try to create it if its not there.
+     *
+     * @param string $subdir name of subdir
+     * @param array  $create default is to try to create the subdir
+     *
+     * @return string | boolean as real path to the subdir or
+     *                          false if it does not exists
+     */
+    public function getPathToSubdir($subdir, $create = true)
+    {
+        $path = realpath($this->path . "/" . $subdir);
+
+        if (is_dir($path)) {
+            return $path;
+        }
+
+        if ($create && is_writable($this->path)) {
+            $path = $this->path . "/" . $subdir;
+
+            if (mkdir($path)) {
+                return realpath($path);
+            }
+        }
+
+        return false;
+    }
+
+
+
+    /**
+     * Get status of the cache subdir.
+     *
+     * @param string $subdir name of subdir
+     *
+     * @return string with status
+     */
+    public function getStatusOfSubdir($subdir)
+    {
+        $path = realpath($this->path . "/" . $subdir);
+
+        $exists = is_dir($path); 
+        $res  = $exists ? "exists" : "does not exist";
+        
+        if ($exists) {
+            $res .= is_writable($path) ? ", writable" : ", not writable";
+        }
+
+        return $res;
+    }
+
+
+
+    /**
+     * Remove the cache subdir.
+     *
+     * @param string $subdir name of subdir
+     *
+     * @return null | boolean true if success else false, null if no operation
+     */
+    public function removeSubdir($subdir)
+    {
+        $path = realpath($this->path . "/" . $subdir);
+
+        if (is_dir($path)) {
+            return rmdir($path);
+        }
+
+        return null;
+    }
+}