[PATCH] Add a bit of developer documentation to pull.h

Describe what to implement in fetch() and fetch_ref() for
pull backend writers a bit better.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

pull.h

 #ifndef PULL_H
 #define PULL_H
 
-/** To be provided by the particular implementation. **/
+/*
+ * Fetch object given SHA1 from the remote, and store it locally under
+ * GIT_OBJECT_DIRECTORY.  Return 0 on success, -1 on failure.  To be
+ * provided by the particular implementation.
+ */
 extern int fetch(unsigned char *sha1);
 
+/*
+ * Fetch ref (relative to $GIT_DIR/refs) from the remote, and store
+ * the 20-byte SHA1 in sha1.  Return 0 on success, -1 on failure.  To
+ * be provided by the particular implementation.
+ */
 extern int fetch_ref(char *ref, unsigned char *sha1);
 
-/** If set, the ref filename to write the target value to. **/
+/* If set, the ref filename to write the target value to. */
 extern const char *write_ref;
 
-/** If set, the hash that the current value of write_ref must be. **/
+/* If set, the hash that the current value of write_ref must be. */
 extern const unsigned char *current_ref;
 
-/** Set to fetch the target tree. */
+/* Set to fetch the target tree. */
 extern int get_tree;
 
-/** Set to fetch the commit history. */
+/* Set to fetch the commit history. */
 extern int get_history;
 
-/** Set to fetch the trees in the commit history. **/
+/* Set to fetch the trees in the commit history. */
 extern int get_all;
 
 /* Set to zero to skip the check for delta object base;