struct ref_update: move "have_old" into "flags"

Instead of having a separate have_old field, record this boolean value
as a bit in the "flags" field.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/refs.c b/refs.c
index a203e44559b5bbc0a63527b5086e9343fa136cac..e3a2ba8bd7991fd70244b18f9fc9d5ff31b73ce2 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -41,11 +41,17 @@ static unsigned char refname_disposition[256] = {
 #define REF_DELETING   0x02
 
 /*
- * Used as a flag to ref_transaction_delete when a loose ref is being
+ * Used as a flag in ref_update::flags when a loose ref is being
  * pruned.
  */
 #define REF_ISPRUNING  0x04
 
+/*
+ * Used as a flag in ref_update::flags when old_sha1 should be
+ * checked.
+ */
+#define REF_HAVE_OLD   0x08
+
 /*
  * Try to read one refname component from the front of refname.
  * Return the length of the component found, or -1 if the component is
@@ -3563,16 +3569,20 @@ int for_each_reflog(each_ref_fn fn, void *cb_data)
 }
 
 /**
- * Information needed for a single ref update.  Set new_sha1 to the
- * new value or to zero to delete the ref.  To check the old value
- * while locking the ref, set have_old to 1 and set old_sha1 to the
- * value or to zero to ensure the ref does not exist before update.
+ * Information needed for a single ref update. Set new_sha1 to the new
+ * value or to null_sha1 to delete the ref. To check the old value
+ * while the ref is locked, set (flags & REF_HAVE_OLD) and set
+ * old_sha1 to the old value, or to null_sha1 to ensure the ref does
+ * not exist before update.
  */
 struct ref_update {
        unsigned char new_sha1[20];
        unsigned char old_sha1[20];
-       unsigned int flags; /* REF_NODEREF? */
-       int have_old; /* 1 if old_sha1 is valid, 0 otherwise */
+       /*
+        * One or more of REF_HAVE_OLD, REF_NODEREF,
+        * REF_DELETING, and REF_ISPRUNING:
+        */
+       unsigned int flags;
        struct ref_lock *lock;
        int type;
        char *msg;
@@ -3666,10 +3676,11 @@ int ref_transaction_update(struct ref_transaction *transaction,
 
        update = add_update(transaction, refname);
        hashcpy(update->new_sha1, new_sha1);
-       update->flags = flags;
-       update->have_old = have_old;
-       if (have_old)
+       if (have_old) {
                hashcpy(update->old_sha1, old_sha1);
+               flags |= REF_HAVE_OLD;
+       }
+       update->flags = flags;
        if (msg)
                update->msg = xstrdup(msg);
        return 0;
@@ -3785,13 +3796,13 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 
                if (is_null_sha1(update->new_sha1))
                        flags |= REF_DELETING;
-               update->lock = lock_ref_sha1_basic(update->refname,
-                                                  (update->have_old ?
-                                                   update->old_sha1 :
-                                                   NULL),
-                                                  NULL,
-                                                  flags,
-                                                  &update->type);
+               update->lock = lock_ref_sha1_basic(
+                               update->refname,
+                               ((update->flags & REF_HAVE_OLD) ?
+                                update->old_sha1 : NULL),
+                               NULL,
+                               flags,
+                               &update->type);
                if (!update->lock) {
                        ret = (errno == ENOTDIR)
                                ? TRANSACTION_NAME_CONFLICT