xmldb_init -> xmldb_create

datastore/README.md

@@ -9,8 +9,59 @@ The datastore is primarily designed to be used by Clixon but can be used
 separately.  See datastore_client.c for an example of how to use a
 datastore plugin for other applications
 
-Can we equate a file that does not exist with an empty file?
-Or is empty file same as <config/>?
-Three states:
-NULL <---> "" <---> "<config/>"
-which are valid?
+## The functional API
+```
+int xmldb_plugin_load(clicon_handle h, char *filename);
+int xmldb_plugin_unload(clicon_handle h);
+int xmldb_connect(clicon_handle h);
+int xmldb_disconnect(clicon_handle h);
+int xmldb_getopt(clicon_handle h, char *optname, void **value);
+int xmldb_setopt(clicon_handle h, char *optname, void *value);
+int xmldb_get(clicon_handle h, char *db, char *xpath,
+	      cxobj **xtop, cxobj ***xvec, size_t *xlen);
+int xmldb_put(clicon_handle h, char *db, enum operation_type op, 
+	      char *api_path,  cxobj *xt);
+int xmldb_copy(clicon_handle h, char *from, char *to);
+int xmldb_lock(clicon_handle h, char *db, int pid);
+int xmldb_unlock(clicon_handle h, char *db);
+int xmldb_unlock_all(clicon_handle h, int pid);
+int xmldb_islocked(clicon_handle h, char *db);
+int xmldb_exists(clicon_handle h, char *db);
+int xmldb_delete(clicon_handle h, char *db);
+int xmldb_init(clicon_handle h, char *db);
+```
+
+## Using the API
+
+This section described how the API is used. Please refer to datastore/datastore_client.c for an example of an actual implementation.
+
+### Prerequisities
+To use the API, a client needs the following:
+- A clicon handle. 
+- A datastore plugin, such as a text.so or keyvalue.so. These are normally built and installed at Clixon make.
+- A directory where to store the datastores
+- A yang specification. This needs to be parsed using the Clixon yang_parse() method.
+
+### Dynamics
+
+A client calling the API needs to load a plugin and connect to a
+datastore. In principle, you cannot connect to several datastores,
+even concurrently, but in practice in Clixon, you connect to a single
+store.
+
+Within a datastore, there may be 
+
+```
+  h = clicon_handle_init();
+  xmldb_plugin_load(h, plugin);
+```
+The plugin is the complete path-name of a file.
+
+Thereafter, a connection is made to a specific plugin, such as a text plugin. It is possible to connect to several datastore at once, although this is not supported by CLixon:
+```
+xmldb_connect(h);
+xmldb_setopt(h, "dbdir", dbdir);
+xmldb_setopt(h, "yangspec", yspec);
+```
+
+

datastore/datastore_client.c

@@ -286,7 +286,7 @@ main(int argc, char **argv)
     else if (strcmp(cmd, "init")==0){
 	if (argc != 1)
 	    usage(argv0);
-	if (xmldb_init(h, db) < 0)
+	if (xmldb_create(h, db) < 0)
 	    goto done;
     }
     else{