--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cache/README.txt	Thu Apr 02 15:28:21 2009 +0000
@@ -0,0 +1,39 @@
+
+Cache hook format:
+  $cache['hook_name'] = array(
+    'weight' => integer, // optional
+    'file' => '/full/path/to/include/file',
+    'function' => 'function_name',
+  );
+
+Supported hooks:
+
+ - hook_init
+    Alter which advertisements are selecting from.
+
+ - hook_filter
+    Filter out invalid advertisements.
+
+ - hook_select
+    Alter how advertisements are selected.
+
+OLD README (this may not be accurate anymore):
+TODO: Update.
+Ad caches are defined through external modules.  Ad caches are composed of a
+module 'ad_cache_TYPE.module' and an include file 'ad_cache_TYPE.inc' that live
+in the 'cache/TYPE' subdirectory where 'TYPE' is replaced with the type of
+cache.  For example, the included file cache lives in 'cache/file'.
+
+The ad_cache_TYPE.inc file must have a function named ad_cache_TYPE() which is
+used to display ads.  It can optionally include a function titled
+ad_cache_TYPE_variables used to extract any necessary variables from the global
+$_GET array (this can also be used to override values that would normally be
+set from $_GET).  Any functions used by this code without bootstrapping Drupal
+should also be in this file.
+
+The ad_cache_TYPE.module file should define the drupal _help() hook so the
+module can be enabled.  It should also define the _adcacheapi() hook allowing
+for configuration and processing.  Any functions used by this code after
+bootstrapping Drupal should also be in this module.
+
+Refer to cache/file/* for an implementation example.