Refactor "tracking statistics" code used by "git checkout"
[git/git.git] / remote.c
index ff2c802..bd5c3be 100644 (file)
--- a/remote.c
+++ b/remote.c
@@ -1,6 +1,9 @@
 #include "cache.h"
 #include "remote.h"
 #include "refs.h"
 #include "cache.h"
 #include "remote.h"
 #include "refs.h"
+#include "commit.h"
+#include "diff.h"
+#include "revision.h"
 
 static struct refspec s_tag_refspec = {
        0,
 
 static struct refspec s_tag_refspec = {
        0,
@@ -1222,3 +1225,113 @@ int resolve_remote_symref(struct ref *ref, struct ref *list)
                }
        return 1;
 }
                }
        return 1;
 }
+
+/*
+ * Return true if there is anything to report, otherwise false.
+ */
+int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
+{
+       unsigned char sha1[20];
+       struct commit *ours, *theirs;
+       char symmetric[84];
+       struct rev_info revs;
+       const char *rev_argv[10], *base;
+       int rev_argc;
+
+       /*
+        * Nothing to report unless we are marked to build on top of
+        * somebody else.
+        */
+       if (!branch ||
+           !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
+               return 0;
+
+       /*
+        * If what we used to build on no longer exists, there is
+        * nothing to report.
+        */
+       base = branch->merge[0]->dst;
+       if (!resolve_ref(base, sha1, 1, NULL))
+               return 0;
+       theirs = lookup_commit(sha1);
+       if (!theirs)
+               return 0;
+
+       if (!resolve_ref(branch->refname, sha1, 1, NULL))
+               return 0;
+       ours = lookup_commit(sha1);
+       if (!ours)
+               return 0;
+
+       /* are we the same? */
+       if (theirs == ours)
+               return 0;
+
+       /* Run "rev-list --left-right ours...theirs" internally... */
+       rev_argc = 0;
+       rev_argv[rev_argc++] = NULL;
+       rev_argv[rev_argc++] = "--left-right";
+       rev_argv[rev_argc++] = symmetric;
+       rev_argv[rev_argc++] = "--";
+       rev_argv[rev_argc] = NULL;
+
+       strcpy(symmetric, sha1_to_hex(ours->object.sha1));
+       strcpy(symmetric + 40, "...");
+       strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
+
+       init_revisions(&revs, NULL);
+       setup_revisions(rev_argc, rev_argv, &revs, NULL);
+       prepare_revision_walk(&revs);
+
+       /* ... and count the commits on each side. */
+       *num_ours = 0;
+       *num_theirs = 0;
+       while (1) {
+               struct commit *c = get_revision(&revs);
+               if (!c)
+                       break;
+               if (c->object.flags & SYMMETRIC_LEFT)
+                       (*num_ours)++;
+               else
+                       (*num_theirs)++;
+       }
+       return 1;
+}
+
+/*
+ * Return true when there is anything to report, otherwise false.
+ */
+int format_tracking_info(struct branch *branch, struct strbuf *sb)
+{
+       int num_ours, num_theirs;
+       const char *base, *remote_msg;
+
+       if (!stat_tracking_info(branch, &num_ours, &num_theirs))
+               return 0;
+
+       base = branch->merge[0]->dst;
+       if (!prefixcmp(base, "refs/remotes/")) {
+               remote_msg = " remote";
+               base += strlen("refs/remotes/");
+       } else {
+               remote_msg = "";
+       }
+       if (!num_theirs)
+               strbuf_addf(sb, "Your branch is ahead of the tracked%s branch '%s' "
+                           "by %d commit%s.\n",
+                           remote_msg, base,
+                           num_ours, (num_ours == 1) ? "" : "s");
+       else if (!num_ours)
+               strbuf_addf(sb, "Your branch is behind the tracked%s branch '%s' "
+                           "by %d commit%s,\n"
+                           "and can be fast-forwarded.\n",
+                           remote_msg, base,
+                           num_theirs, (num_theirs == 1) ? "" : "s");
+       else
+               strbuf_addf(sb, "Your branch and the tracked%s branch '%s' "
+                           "have diverged,\nand respectively "
+                           "have %d and %d different commit(s) each.\n",
+                           remote_msg, base,
+                           num_ours, num_theirs);
+       return 1;
+}