Merge branch 'jc/report-tracking'

* jc/report-tracking:
  branch -r -v: do not spit out garbage
  stat_tracking_info(): clear object flags used during counting
  git-branch -v: show the remote tracking statistics
  git-status: show the remote tracking statistics
  Refactor "tracking statistics" code used by "git checkout"

7 files changed, 244 insertions, 90 deletions

diff --git a/builtin-branch.c b/builtin-branch.c
index d279702ba9..ff71f3d8a6 100644
--- a/builtin-branch.c
+++ b/builtin-branch.c
@@ -282,6 +282,21 @@ static int ref_cmp(const void *r1, const void *r2)
 	return strcmp(c1->name, c2->name);
 }
 
+static void fill_tracking_info(char *stat, const char *branch_name)
+{
+	int ours, theirs;
+	struct branch *branch = branch_get(branch_name);
+
+	if (!stat_tracking_info(branch, &ours, &theirs) || (!ours && !theirs))
+		return;
+	if (!ours)
+		sprintf(stat, "[behind %d] ", theirs);
+	else if (!theirs)
+		sprintf(stat, "[ahead %d] ", ours);
+	else
+		sprintf(stat, "[ahead %d, behind %d] ", ours, theirs);
+}
+
 static void print_ref_item(struct ref_item *item, int maxwidth, int verbose,
 			   int abbrev, int current)
 {
@@ -310,8 +325,10 @@ static void print_ref_item(struct ref_item *item, int maxwidth, int verbose,
 	if (verbose) {
 		struct strbuf subject;
 		const char *sub = " **** invalid ref ****";
+		char stat[128];
 
 		strbuf_init(&subject, 0);
+		stat[0] = '\0';
 
 		commit = lookup_commit(item->sha1);
 		if (commit && !parse_commit(commit)) {
@@ -319,10 +336,15 @@ static void print_ref_item(struct ref_item *item, int maxwidth, int verbose,
 					    &subject, 0, NULL, NULL, 0, 0);
 			sub = subject.buf;
 		}
-		printf("%c %s%-*s%s %s %s\n", c, branch_get_color(color),
+
+		if (item->kind == REF_LOCAL_BRANCH)
+			fill_tracking_info(stat, item->name);
+
+		printf("%c %s%-*s%s %s %s%s\n", c, branch_get_color(color),
 		       maxwidth, item->name,
 		       branch_get_color(COLOR_BRANCH_RESET),
-		       find_unique_abbrev(item->sha1, abbrev), sub);
+		       find_unique_abbrev(item->sha1, abbrev),
+		       stat, sub);
 		strbuf_release(&subject);
 	} else {
 		printf("%c %s%s%s\n", c, branch_get_color(color), item->name,
diff --git a/builtin-checkout.c b/builtin-checkout.c
index 93ea69bfaa..d6641c2c56 100644
--- a/builtin-checkout.c
+++ b/builtin-checkout.c
@@ -305,97 +305,15 @@ static int merge_working_tree(struct checkout_opts *opts,
 	return 0;
 }
 
-static void report_tracking(struct branch_info *new, struct checkout_opts *opts)
+static void report_tracking(struct branch_info *new)
 {
-	/*
-	 * We have switched to a new branch; is it building on
-	 * top of another branch, and if so does that other branch
-	 * have changes we do not have yet?
-	 */
-	char *base;
-	unsigned char sha1[20];
-	struct commit *ours, *theirs;
-	char symmetric[84];
-	struct rev_info revs;
-	const char *rev_argv[10];
-	int rev_argc;
-	int num_ours, num_theirs;
-	const char *remote_msg;
+	struct strbuf sb = STRBUF_INIT;
 	struct branch *branch = branch_get(new->name);
 
-	/*
-	 * 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;
-
-	/*
-	 * 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))
+	if (!format_tracking_info(branch, &sb))
 		return;
-
-	theirs = lookup_commit(sha1);
-	ours = new->commit;
-	if (!hashcmp(sha1, ours->object.sha1))
-		return; /* we are the same */
-
-	/* 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++;
-	}
-
-	if (!prefixcmp(base, "refs/remotes/")) {
-		remote_msg = " remote";
-		base += strlen("refs/remotes/");
-	} else {
-		remote_msg = "";
-	}
-
-	if (!num_theirs)
-		printf("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)
-		printf("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
-		printf("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);
+	fputs(sb.buf, stdout);
+	strbuf_release(&sb);
 }
 
 static void update_refs_for_switch(struct checkout_opts *opts,
@@ -441,7 +359,7 @@ static void update_refs_for_switch(struct checkout_opts *opts,
 	remove_branch_state();
 	strbuf_release(&msg);
 	if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
-		report_tracking(new, opts);
+		report_tracking(new);
 }
 
 static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
diff --git a/remote.c b/remote.c
index ff2c802167..df8bd72ba9 100644
--- a/remote.c
+++ b/remote.c
@@ -1,6 +1,9 @@
 #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,
@@ -1222,3 +1225,117 @@ int resolve_remote_symref(struct ref *ref, struct ref *list)
 		}
 	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)++;
+	}
+
+	/* clear object flags smudged by the above traversal */
+	clear_commit_marks(ours, ALL_REV_FLAGS);
+	clear_commit_marks(theirs, ALL_REV_FLAGS);
+	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;
+}
diff --git a/remote.h b/remote.h
index 8eed87ba5a..091b1d041f 100644
--- a/remote.h
+++ b/remote.h
@@ -129,4 +129,8 @@ enum match_refs_flags {
 	MATCH_REFS_MIRROR	= (1 << 1),
 };
 
+/* Reporting of tracking info */
+int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs);
+int format_tracking_info(struct branch *branch, struct strbuf *sb);
+
 #endif
diff --git a/revision.h b/revision.h
index 83f364ace2..f57b6c5d9a 100644
--- a/revision.h
+++ b/revision.h
@@ -11,6 +11,7 @@
 #define ADDED		(1u<<7)	/* Parents already parsed and added? */
 #define SYMMETRIC_LEFT	(1u<<8)
 #define TOPOSORT	(1u<<9)	/* In the active toposort list.. */
+#define ALL_REV_FLAGS	((1u<<10)-1)
 
 struct rev_info;
 struct log_info;
diff --git a/t/t6040-tracking-info.sh b/t/t6040-tracking-info.sh
new file mode 100755
index 0000000000..aac212e936
--- /dev/null
+++ b/t/t6040-tracking-info.sh
@@ -0,0 +1,70 @@
+#!/bin/sh
+
+test_description='remote tracking stats'
+
+. ./test-lib.sh
+
+advance () {
+	echo "$1" >"$1" &&
+	git add "$1" &&
+	test_tick &&
+	git commit -m "$1"
+}
+
+test_expect_success setup '
+	for i in a b c;
+	do
+		advance $i || break
+	done &&
+	git clone . test &&
+	(
+		cd test &&
+		git checkout -b b1 origin &&
+		git reset --hard HEAD^ &&
+		advance d &&
+		git checkout -b b2 origin &&
+		git reset --hard b1 &&
+		git checkout -b b3 origin &&
+		git reset --hard HEAD^ &&
+		git checkout -b b4 origin &&
+		advance e &&
+		advance f
+	)
+'
+
+script='s/^..\(b.\)[	 0-9a-f]*\[\([^]]*\)\].*/\1 \2/p'
+cat >expect <<\EOF
+b1 ahead 1, behind 1
+b2 ahead 1, behind 1
+b3 behind 1
+b4 ahead 2
+EOF
+
+test_expect_success 'branch -v' '
+	(
+		cd test &&
+		git branch -v
+	) |
+	sed -n -e "$script" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'checkout' '
+	(
+		cd test && git checkout b1
+	) >actual &&
+	grep -e "have 1 and 1 different" actual
+'
+
+test_expect_success 'status' '
+	(
+		cd test &&
+		git checkout b1 >/dev/null &&
+		# reports nothing to commit
+		test_must_fail git status
+	) >actual &&
+	grep -e "have 1 and 1 different" actual
+'
+
+
+test_done
diff --git a/wt-status.c b/wt-status.c
index e7d42d0491..889e50f89f 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -9,6 +9,7 @@
 #include "diffcore.h"
 #include "quote.h"
 #include "run-command.h"
+#include "remote.h"
 
 int wt_status_relative_paths = 1;
 int wt_status_use_color = -1;
@@ -315,6 +316,25 @@ static void wt_status_print_verbose(struct wt_status *s)
 	run_diff_index(&rev, 1);
 }
 
+static void wt_status_print_tracking(struct wt_status *s)
+{
+	struct strbuf sb = STRBUF_INIT;
+	const char *cp, *ep;
+	struct branch *branch;
+
+	assert(s->branch && !s->is_initial);
+	if (prefixcmp(s->branch, "refs/heads/"))
+		return;
+	branch = branch_get(s->branch + 11);
+	if (!format_tracking_info(branch, &sb))
+		return;
+
+	for (cp = sb.buf; (ep = strchr(cp, '\n')) != NULL; cp = ep + 1)
+		color_fprintf_ln(s->fp, color(WT_STATUS_HEADER),
+				 "# %.*s", (int)(ep - cp), cp);
+	color_fprintf_ln(s->fp, color(WT_STATUS_HEADER), "#");
+}
+
 void wt_status_print(struct wt_status *s)
 {
 	unsigned char sha1[20];
@@ -333,6 +353,8 @@ void wt_status_print(struct wt_status *s)
 		}
 		color_fprintf(s->fp, color(WT_STATUS_HEADER), "# ");
 		color_fprintf_ln(s->fp, branch_color, "%s%s", on_what, branch_name);
+		if (!s->is_initial)
+			wt_status_print_tracking(s);
 	}
 
 	if (s->is_initial) {