Re: [PATCH v2 3/3] fetch: reduce duplicate in ref update status lines

[Duy Nguyen <pclouds@gmail.com>]

On Fri, Jun 03, 2016 at 10:53:27AM -0400, Marc Branchaud wrote:
> On 2016-06-03 07:08 AM, Nguyễn Thái Ngọc Duy wrote:
> > When there are lots of ref updates, each has different name length, this
> > will make it easier to look because the variable part is at the end.
> 
> s/look/read/
> 
> For the record, I prefer the earlier stair-step format to this
> 	{xxx -> yyy}/foo
> stuff.
> 
> Peff suggested that a two-pass approach might not be too bad, but had 
> problems when he tried it with extra-long refs.  Maybe those problems 
> could be dealt with, and we could get a simple, aligned output?

The good thing about 2/3 is we can customize the output easily and
even switch format with config variables. But let's play without
config vars for now. A 3/3 replacement that adds another pass to
calculate column width is at the end.

> What if we detect when the full line exceeds the terminal width, and 
> insert a newline after the remote ref and indent the ->  to the same 
> offset as its surrounding lines, like this:
> 
>   * [new branch]      2nd-index -> pclouds/2nd-index
>   * [new branch]      some-kind-of-long-ref-name
>                                 -> pclouds/some-kind-of-long-ref-name
>   * [new branch]      3nd-index -> pclouds/3nd-index

The patch does not do fancy stuff like this yet, but it can because
lines exceeding terminal width is already excluded from column width
calculation. So far the output looks good on my terminal (192 chars,
can't overflow or refnames are insanely long)

-- 8< --
diff --git a/builtin/fetch.c b/builtin/fetch.c
index a7f152a..5e1e5c9 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -15,6 +15,7 @@
 #include "submodule.h"
 #include "connected.h"
 #include "argv-array.h"
+#include "utf8.h"
 
 static const char * const builtin_fetch_usage[] = {
 	N_("git fetch [<options>] [<repository> [<refspec>...]]"),
@@ -449,14 +450,26 @@ fail:
 			   : STORE_REF_ERROR_OTHER;
 }
 
-#define REFCOL_WIDTH  10
+static int refcol_width = 10;
+
+static void adjust_refcol_width(const char *remote, const char *local)
+{
+	int max = term_columns();
+	int rlen = utf8_strwidth(remote);
+	int llen = utf8_strwidth(local);
+
+	if (21 /* flag summary */ + rlen + 4 /* => */ + llen >= max)
+		return;
+	if (refcol_width < rlen)
+		refcol_width = rlen;
+}
 
 static void format_display(struct strbuf *display, char code,
 			   const char *summary, const char *error,
 			   const char *remote, const char *local)
 {
 	strbuf_addf(display, "%c %-*s ", code, TRANSPORT_SUMMARY(summary));
-	strbuf_addf(display, "%-*s -> %s", REFCOL_WIDTH, remote, local);
+	strbuf_addf(display, "%-*s -> %s", refcol_width, remote, local);
 	if (error)
 		strbuf_addf(display, "  (%s)", error);
 }
@@ -618,6 +631,20 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
 		goto abort;
 	}
 
+	/*
+	 * go through all refs to determine column size for
+	 * "remote -> local" output
+	 */
+	for (rm = ref_map; rm; rm = rm->next) {
+		if (rm->status == REF_STATUS_REJECT_SHALLOW ||
+		    !rm->peer_ref ||
+		    !strcmp(rm->name, "HEAD"))
+			continue;
+
+		adjust_refcol_width(prettify_refname(rm->name),
+				    prettify_refname(rm->peer_ref->name));
+	}
+
 	/*
 	 * We do a pass for each fetch_head_status type in their enum order, so
 	 * merged entries are written before not-for-merge. That lets readers
-- 8< --