builtin-remote: new show output style for push refspecs

The existing output of "git remote show <remote>" with respect to push
ref specs is basically just to show the raw refspec. This patch teaches
the command to interpret the refspecs and show how each branch will be
pushed to the destination. The output gives the user an idea of what
"git push" should do if it is run w/o any arguments.

Example new output:

1a. Typical output with no push refspec (i.e. matching branches only)

$ git remote show origin
* remote origin
  [...]
  Local refs configured for 'git push':
    master pushes to master (up to date)
    next   pushes to next   (local out of date)

1b. Same as above, w/o querying the remote:

$ git remote show origin -n
* remote origin
  [...]
  Local ref configured for 'git push' (status not queried):
    (matching) pushes to (matching)

2a. With a forcing refspec (+), and a new topic
    (something like push = refs/heads/*:refs/heads/*):

$ git remote show origin
* remote origin
  [...]
  Local refs configured for 'git push':
    master     pushes to master    (fast forwardable)
    new-topic  pushes to new-topic (create)
    next       pushes to next      (local out of date)
    pu         forces to pu        (up to date)

2b. Same as above, w/o querying the remote

$ git remote show origin -n
* remote origin
  [...]
  Local refs configured for 'git push' (status not queried):
    master     pushes to master
    new-topic  pushes to new-topic
    next       pushes to next
    pu         forces to pu

3. With a remote configured as a mirror:

* remote backup
  [...]
  Local refs will be mirrored by 'git push'

Signed-off-by: Jay Soffian <jaysoffian@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 185 insertions, 16 deletions

diff --git a/builtin-remote.c b/builtin-remote.c
index 379826eed..7e82a52b7 100644
--- a/builtin-remote.c
+++ b/builtin-remote.c
@@ -21,6 +21,7 @@ static const char * const builtin_remote_usage[] = {
 
 #define GET_REF_STATES (1<<0)
 #define GET_HEAD_NAMES (1<<1)
+#define GET_PUSH_REF_STATES (1<<2)
 
 static int verbose;
 
@@ -220,7 +221,7 @@ static void read_branches(void)
 
 struct ref_states {
 	struct remote *remote;
-	struct string_list new, stale, tracked, heads;
+	struct string_list new, stale, tracked, heads, push;
 	int queried;
 };
 
@@ -275,6 +276,112 @@ static int get_ref_states(const struct ref *remote_refs, struct ref_states *stat
 	return 0;
 }
 
+struct push_info {
+	char *dest;
+	int forced;
+	enum {
+		PUSH_STATUS_CREATE = 0,
+		PUSH_STATUS_DELETE,
+		PUSH_STATUS_UPTODATE,
+		PUSH_STATUS_FASTFORWARD,
+		PUSH_STATUS_OUTOFDATE,
+		PUSH_STATUS_NOTQUERIED,
+	} status;
+};
+
+static int get_push_ref_states(const struct ref *remote_refs,
+	struct ref_states *states)
+{
+	struct remote *remote = states->remote;
+	struct ref *ref, *local_refs, *push_map, **push_tail;
+	if (remote->mirror)
+		return 0;
+
+	local_refs = get_local_heads();
+	ref = push_map = copy_ref_list(remote_refs);
+	while (ref->next)
+		ref = ref->next;
+	push_tail = &ref->next;
+
+	match_refs(local_refs, push_map, &push_tail, remote->push_refspec_nr,
+		   remote->push_refspec, MATCH_REFS_NONE);
+
+	states->push.strdup_strings = 1;
+	for (ref = push_map; ref; ref = ref->next) {
+		struct string_list_item *item;
+		struct push_info *info;
+
+		if (!ref->peer_ref)
+			continue;
+		hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
+
+		item = string_list_append(abbrev_branch(ref->peer_ref->name),
+					  &states->push);
+		item->util = xcalloc(sizeof(struct push_info), 1);
+		info = item->util;
+		info->forced = ref->force;
+		info->dest = xstrdup(abbrev_branch(ref->name));
+
+		if (is_null_sha1(ref->new_sha1)) {
+			info->status = PUSH_STATUS_DELETE;
+		} else if (!hashcmp(ref->old_sha1, ref->new_sha1))
+			info->status = PUSH_STATUS_UPTODATE;
+		else if (is_null_sha1(ref->old_sha1))
+			info->status = PUSH_STATUS_CREATE;
+		else if (has_sha1_file(ref->old_sha1) &&
+			 ref_newer(ref->new_sha1, ref->old_sha1))
+			info->status = PUSH_STATUS_FASTFORWARD;
+		else
+			info->status = PUSH_STATUS_OUTOFDATE;
+		// ref->peer_ref = NULL; /* local ref which is freed below */
+	}
+	free_refs(local_refs);
+	free_refs(push_map);
+	return 0;
+}
+
+static int get_push_ref_states_noquery(struct ref_states *states)
+{
+	int i;
+	struct remote *remote = states->remote;
+	struct string_list_item *item;
+	struct push_info *info;
+
+	if (remote->mirror)
+		return 0;
+
+	states->push.strdup_strings = 1;
+	if (!remote->push_refspec_nr) {
+		item = string_list_append("(matching)", &states->push);
+		info = item->util = xcalloc(sizeof(struct push_info), 1);
+		info->status = PUSH_STATUS_NOTQUERIED;
+		info->dest = xstrdup(item->string);
+	}
+	for (i = 0; i < remote->push_refspec_nr; i++) {
+		struct refspec *spec = remote->push + i;
+		char buf[PATH_MAX];
+		if (spec->matching)
+			item = string_list_append("(matching)", &states->push);
+		else if (spec->pattern) {
+			snprintf(buf, (sizeof(buf)), "%s*", spec->src);
+			item = string_list_append(buf, &states->push);
+			snprintf(buf, (sizeof(buf)), "%s*", spec->dst);
+		} else if (strlen(spec->src))
+			item = string_list_append(spec->src, &states->push);
+		else
+			item = string_list_append("(delete)", &states->push);
+
+		info = item->util = xcalloc(sizeof(struct push_info), 1);
+		info->forced = spec->force;
+		info->status = PUSH_STATUS_NOTQUERIED;
+		if (spec->pattern)
+			info->dest = xstrdup(buf);
+		else
+			info->dest = xstrdup(spec->dst ? spec->dst : item->string);
+	}
+	return 0;
+}
+
 static int get_head_names(const struct ref *remote_refs, struct ref_states *states)
 {
 	struct ref *ref, *matches;
@@ -644,12 +751,20 @@ static int rm(int argc, const char **argv)
 	return result;
 }
 
+void clear_push_info(void *util, const char *string)
+{
+	struct push_info *info = util;
+	free(info->dest);
+	free(info);
+}
+
 static void free_remote_ref_states(struct ref_states *states)
 {
 	string_list_clear(&states->new, 0);
 	string_list_clear(&states->stale, 0);
 	string_list_clear(&states->tracked, 0);
 	string_list_clear(&states->heads, 0);
+	string_list_clear_func(&states->push, clear_push_info);
 }
 
 static int append_ref_to_tracked_list(const char *refname,
@@ -693,9 +808,12 @@ static int get_remote_ref_states(const char *name,
 			get_ref_states(remote_refs, states);
 		if (query & GET_HEAD_NAMES)
 			get_head_names(remote_refs, states);
+		if (query & GET_PUSH_REF_STATES)
+			get_push_ref_states(remote_refs, states);
 	} else {
 		for_each_ref(append_ref_to_tracked_list, states);
 		sort_string_list(&states->tracked);
+		get_push_ref_states_noquery(states);
 	}
 
 	return 0;
@@ -704,7 +822,7 @@ static int get_remote_ref_states(const char *name,
 struct show_info {
 	struct string_list *list;
 	struct ref_states *states;
-	int width;
+	int width, width2;
 	int any_rebase;
 };
 
@@ -799,6 +917,58 @@ int show_local_info_item(struct string_list_item *item, void *cb_data)
 	return 0;
 }
 
+int add_push_to_show_info(struct string_list_item *push_item, void *cb_data)
+{
+	struct show_info *show_info = cb_data;
+	struct push_info *push_info = push_item->util;
+	struct string_list_item *item;
+	int n;
+	if ((n = strlen(push_item->string)) > show_info->width)
+		show_info->width = n;
+	if ((n = strlen(push_info->dest)) > show_info->width2)
+		show_info->width2 = n;
+	item = string_list_append(push_item->string, show_info->list);
+	item->util = push_item->util;
+	return 0;
+}
+
+int show_push_info_item(struct string_list_item *item, void *cb_data)
+{
+	struct show_info *show_info = cb_data;
+	struct push_info *push_info = item->util;
+	char *src = item->string, *status = NULL;
+
+	switch (push_info->status) {
+	case PUSH_STATUS_CREATE:
+		status = "create";
+		break;
+	case PUSH_STATUS_DELETE:
+		status = "delete";
+		src = "(none)";
+		break;
+	case PUSH_STATUS_UPTODATE:
+		status = "up to date";
+		break;
+	case PUSH_STATUS_FASTFORWARD:
+		status = "fast forwardable";
+		break;
+	case PUSH_STATUS_OUTOFDATE:
+		status = "local out of date";
+		break;
+	case PUSH_STATUS_NOTQUERIED:
+		break;
+	}
+	if (status)
+		printf("    %-*s %s to %-*s (%s)\n", show_info->width, src,
+			push_info->forced ? "forces" : "pushes",
+			show_info->width2, push_info->dest, status);
+	else
+		printf("    %-*s %s to %s\n", show_info->width, src,
+			push_info->forced ? "forces" : "pushes",
+			push_info->dest);
+	return 0;
+}
+
 static int show(int argc, const char **argv)
 {
 	int no_query = 0, result = 0, query_flag = 0;
@@ -817,7 +987,7 @@ static int show(int argc, const char **argv)
 		return show_all();
 
 	if (!no_query)
-		query_flag = (GET_REF_STATES | GET_HEAD_NAMES);
+		query_flag = (GET_REF_STATES | GET_HEAD_NAMES | GET_PUSH_REF_STATES);
 
 	memset(&states, 0, sizeof(states));
 	memset(&info, 0, sizeof(info));
@@ -867,19 +1037,18 @@ static int show(int argc, const char **argv)
 		string_list_clear(info.list, 0);
 
 		/* git push info */
-		if (states.remote->push_refspec_nr) {
-			printf("  Local branch%s pushed with 'git push'\n",
-				states.remote->push_refspec_nr > 1 ?
-					"es" : "");
-			for (i = 0; i < states.remote->push_refspec_nr; i++) {
-				struct refspec *spec = states.remote->push + i;
-				printf("    %s%s%s%s\n",
-				       spec->force ? "+" : "",
-				       abbrev_branch(spec->src),
-				       spec->dst ? ":" : "",
-				       spec->dst ? abbrev_branch(spec->dst) : "");
-			}
-		}
+		if (states.remote->mirror)
+			printf("  Local refs will be mirrored by 'git push'\n");
+
+		info.width = info.width2 = 0;
+		for_each_string_list(add_push_to_show_info, &states.push, &info);
+		sort_string_list(info.list);
+		if (info.list->nr)
+			printf("  Local ref%s configured for 'git push'%s:\n",
+				info.list->nr > 1 ? "s" : "",
+				no_query ? " (status not queried)" : "");
+		for_each_string_list(show_push_info_item, info.list, &info);
+		string_list_clear(info.list, 0);
 
 		free_remote_ref_states(&states);
 	}