Initial code for metadata store

This adds a mmap based metadata store for NFS-safe highly
efficient desktop-wide metadata lookup and store.

1 files changed, 58 insertions, 0 deletions

diff --git a/metadata/metatree.h b/metadata/metatree.h
new file mode 100644
index 00000000..b18d30d9
--- /dev/null
+++ b/metadata/metatree.h
@@ -0,0 +1,58 @@
+#include <glib.h>
+
+typedef struct _MetaTree MetaTree;
+
+typedef enum {
+  META_KEY_TYPE_NONE,
+  META_KEY_TYPE_STRING,
+  META_KEY_TYPE_STRINGV
+} MetaKeyType;
+
+typedef gboolean (*meta_tree_dir_enumerate_callback) (const char *entry,
+						      guint64 last_changed,
+						      gboolean has_children,
+						      gboolean has_data,
+						      gpointer user_data);
+
+typedef gboolean (*meta_tree_keys_enumerate_callback) (const char *key,
+						       MetaKeyType type,
+						       gpointer value,
+						       gpointer user_data);
+
+void      meta_tree_free    (MetaTree   *tree);
+MetaTree *meta_tree_open    (const char *filename,
+			     gboolean    for_write);
+void      meta_tree_refresh (MetaTree   *tree); /* May invalidates all strings */
+
+
+MetaKeyType meta_tree_lookup_key_type  (MetaTree                         *tree,
+					const char                       *path,
+					const char                       *key);
+guint64     meta_tree_get_last_changed (MetaTree                         *tree,
+					const char                       *path);
+char *      meta_tree_lookup_string    (MetaTree                         *tree,
+					const char                       *path,
+					const char                       *key);
+char **     meta_tree_lookup_stringv   (MetaTree                         *tree,
+					const char                       *path,
+					const char                       *key);
+void        meta_tree_enumerate_dir    (MetaTree                         *tree,
+					const char                       *path,
+					meta_tree_dir_enumerate_callback  callback,
+					gpointer                          user_data);
+void        meta_tree_enumerate_keys   (MetaTree                         *tree,
+					const char                       *path,
+					meta_tree_keys_enumerate_callback callback,
+					gpointer                          user_data);
+gboolean    meta_tree_flush            (MetaTree                         *tree);
+gboolean    meta_tree_unset            (MetaTree                         *tree,
+					const char                       *path,
+					const char                       *key);
+gboolean    meta_tree_set_string       (MetaTree                         *tree,
+					const char                       *path,
+					const char                       *key,
+					const char                       *value);
+gboolean    meta_tree_set_stringv      (MetaTree                         *tree,
+					const char                       *path,
+					const char                       *key,
+					const char                      **value);