stat_tracking_info: return +1 when branches not equal

Extend stat_tracking_info() to return +1 when branches are not equal and to
take a new "enum ahead_behind_flags" argument to allow skipping the (possibly
expensive) ahead/behind computation.

This will be used in the next commit to allow "git status" to avoid full
ahead/behind calculations for performance reasons.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/ref-filter.c b/ref-filter.c
index 3f9161707e66be86eabaf7347da23a2450ffdd9f..091144e67860065f9864301f9cd2637d2a6419ac 100644 (file)
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -1249,8 +1249,8 @@ static void fill_remote_ref_details(struct used_atom *atom, const char *refname,
        if (atom->u.remote_ref.option == RR_REF)
                *s = show_ref(&atom->u.remote_ref.refname, refname);
        else if (atom->u.remote_ref.option == RR_TRACK) {
-               if (stat_tracking_info(branch, &num_ours,
-                                      &num_theirs, NULL)) {
+               if (stat_tracking_info(branch, &num_ours, &num_theirs,
+                                      NULL, AHEAD_BEHIND_FULL) < 0) {
                        *s = xstrdup(msgs.gone);
                } else if (!num_ours && !num_theirs)
                        *s = "";
@@ -1267,8 +1267,8 @@ static void fill_remote_ref_details(struct used_atom *atom, const char *refname,
                        free((void *)to_free);
                }
        } else if (atom->u.remote_ref.option == RR_TRACKSHORT) {
-               if (stat_tracking_info(branch, &num_ours,
-                                      &num_theirs, NULL))
+               if (stat_tracking_info(branch, &num_ours, &num_theirs,
+                                      NULL, AHEAD_BEHIND_FULL) < 0)
                        return;
 
                if (!num_ours && !num_theirs)

diff --git a/remote.c b/remote.c
index 4e93753e1988afd4a01559951f96142c6dc2e73d..29d47a5852b3d732b27da6260c7ffe3185aa23c1 100644 (file)
--- a/remote.c
+++ b/remote.c
@@ -2007,16 +2007,23 @@ int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
 }
 
 /*
- * Compare a branch with its upstream, and save their differences (number
- * of commits) in *num_ours and *num_theirs. The name of the upstream branch
- * (or NULL if no upstream is defined) is returned via *upstream_name, if it
- * is not itself NULL.
+ * Lookup the upstream branch for the given branch and if present, optionally
+ * compute the commit ahead/behind values for the pair.
+ *
+ * If abf is AHEAD_BEHIND_FULL, compute the full ahead/behind and return the
+ * counts in *num_ours and *num_theirs.  If abf is AHEAD_BEHIND_QUICK, skip
+ * the (potentially expensive) a/b computation (*num_ours and *num_theirs are
+ * set to zero).
+ *
+ * The name of the upstream branch (or NULL if no upstream is defined) is
+ * returned via *upstream_name, if it is not itself NULL.
  *
  * Returns -1 if num_ours and num_theirs could not be filled in (e.g., no
- * upstream defined, or ref does not exist), 0 otherwise.
+ * upstream defined, or ref does not exist).  Returns 0 if the commits are
+ * identical.  Returns 1 if commits are different.
  */
 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
-                      const char **upstream_name)
+                      const char **upstream_name, enum ahead_behind_flags abf)
 {
        struct object_id oid;
        struct commit *ours, *theirs;
@@ -2044,11 +2051,13 @@ int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
        if (!ours)
                return -1;
 
+       *num_theirs = *num_ours = 0;
+
        /* are we the same? */
-       if (theirs == ours) {
-               *num_theirs = *num_ours = 0;
+       if (theirs == ours)
                return 0;
-       }
+       if (abf == AHEAD_BEHIND_QUICK)
+               return 1;
 
        /* Run "rev-list --left-right ours...theirs" internally... */
        argv_array_push(&argv, ""); /* ignored */
@@ -2064,8 +2073,6 @@ int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
                die("revision walk setup failed");
 
        /* ... and count the commits on each side. */
-       *num_ours = 0;
-       *num_theirs = 0;
        while (1) {
                struct commit *c = get_revision(&revs);
                if (!c)
@@ -2081,7 +2088,7 @@ int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
        clear_commit_marks(theirs, ALL_REV_FLAGS);
 
        argv_array_clear(&argv);
-       return 0;
+       return 1;
 }
 
 /*
@@ -2094,7 +2101,8 @@ int format_tracking_info(struct branch *branch, struct strbuf *sb)
        char *base;
        int upstream_is_gone = 0;
 
-       if (stat_tracking_info(branch, &ours, &theirs, &full_base) < 0) {
+       if (stat_tracking_info(branch, &ours, &theirs, &full_base,
+                              AHEAD_BEHIND_FULL) < 0) {
                if (!full_base)
                        return 0;
                upstream_is_gone = 1;

diff --git a/remote.h b/remote.h
index 1f6611be214363a4be363fad959135a9d123cee0..80240f0ada6176d1370cc4ae7f3e4a753fb7efe7 100644 (file)
--- a/remote.h
+++ b/remote.h
@@ -257,9 +257,15 @@ enum match_refs_flags {
        MATCH_REFS_FOLLOW_TAGS  = (1 << 3)
 };
 
+/* Flags for --ahead-behind option. */
+enum ahead_behind_flags {
+       AHEAD_BEHIND_QUICK = 0,  /* just eq/neq reporting */
+       AHEAD_BEHIND_FULL  = 1,  /* traditional a/b reporting */
+};
+
 /* Reporting of tracking info */
 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
-                      const char **upstream_name);
+                      const char **upstream_name, enum ahead_behind_flags abf);
 int format_tracking_info(struct branch *branch, struct strbuf *sb);
 
 struct ref *get_local_heads(void);

diff --git a/wt-status.c b/wt-status.c
index ef26f0744632fdcca919e68ffc58bf414b29e597..1137f27aa6c5c49ce8935b39f3b3799fbcaf9b37 100644 (file)
--- a/wt-status.c
+++ b/wt-status.c
@@ -1796,7 +1796,8 @@ static void wt_shortstatus_print_tracking(struct wt_status *s)
 
        color_fprintf(s->fp, branch_color_local, "%s", branch_name);
 
-       if (stat_tracking_info(branch, &num_ours, &num_theirs, &base) < 0) {
+       if (stat_tracking_info(branch, &num_ours, &num_theirs, &base,
+                              AHEAD_BEHIND_FULL) < 0) {
                if (!base)
                        goto conclude;
 
@@ -1933,7 +1934,8 @@ static void wt_porcelain_v2_print_tracking(struct wt_status *s)
                /* Lookup stats on the upstream tracking branch, if set. */
                branch = branch_get(branch_name);
                base = NULL;
-               ab_info = (stat_tracking_info(branch, &nr_ahead, &nr_behind, &base) == 0);
+               ab_info = (stat_tracking_info(branch, &nr_ahead, &nr_behind,
+                                             &base, AHEAD_BEHIND_FULL) >= 0);
                if (base) {
                        base = shorten_unambiguous_ref(base, 0);
                        fprintf(s->fp, "# branch.upstream %s%c", base, eol);