Pretty-print tagger dates.

We can show commit objects with human readable dates using
various --pretty options, but there was no way to do so with
tags.  This introduces two such ways:

$ git-cat-file -p v1.2.3

shows the tag object with tagger dates in human readable format.

$ git-verify-tag --verbose v1.2.3

uses it to show the contents of the tag object as well as doing
GPG verification.

Signed-off-by: Junio C Hamano <junkio@cox.net>

cat-file.c

@@ -4,6 +4,92 @@
  * Copyright (C) Linus Torvalds, 2005
  */
 #include "cache.h"
+#include "exec_cmd.h"
+
+static void flush_buffer(const char *buf, unsigned long size)
+{
+	while (size > 0) {
+		long ret = xwrite(1, buf, size);
+		if (ret < 0) {
+			/* Ignore epipe */
+			if (errno == EPIPE)
+				break;
+			die("git-cat-file: %s", strerror(errno));
+		} else if (!ret) {
+			die("git-cat-file: disk full?");
+		}
+		size -= ret;
+		buf += ret;
+	}
+}
+
+static int pprint_tag(const unsigned char *sha1, const char *buf, unsigned long size)
+{
+	/* the parser in tag.c is useless here. */
+	const char *endp = buf + size;
+	const char *cp = buf;
+
+	while (cp < endp) {
+		char c = *cp++;
+		if (c != '\n')
+			continue;
+		if (7 <= endp - cp && !memcmp("tagger ", cp, 7)) {
+			const char *tagger = cp;
+
+			/* Found the tagger line.  Copy out the contents
+			 * of the buffer so far.
+			 */
+			flush_buffer(buf, cp - buf);
+
+			/*
+			 * Do something intelligent, like pretty-printing
+			 * the date.
+			 */
+			while (cp < endp) {
+				if (*cp++ == '\n') {
+					/* tagger to cp is a line
+					 * that has ident and time.
+					 */
+					const char *sp = tagger;
+					char *ep;
+					unsigned long date;
+					long tz;
+					while (sp < cp && *sp != '>')
+						sp++;
+					if (sp == cp) {
+						/* give up */
+						flush_buffer(tagger,
+							     cp - tagger);
+						break;
+					}
+					while (sp < cp &&
+					       !('0' <= *sp && *sp <= '9'))
+						sp++;
+					flush_buffer(tagger, sp - tagger);
+					date = strtoul(sp, &ep, 10);
+					tz = strtol(ep, NULL, 10);
+					sp = show_date(date, tz);
+					flush_buffer(sp, strlen(sp));
+					xwrite(1, "\n", 1);
+					break;
+				}
+			}
+			break;
+		}
+		if (cp < endp && *cp == '\n')
+			/* end of header */
+			break;
+	}
+	/* At this point, we have copied out the header up to the end of
+	 * the tagger line and cp points at one past \n.  It could be the
+	 * next header line after the tagger line, or it could be another
+	 * \n that marks the end of the headers.  We need to copy out the
+	 * remainder as is.
+	 */
+	if (cp < endp)
+		flush_buffer(cp, endp - cp);
+	return 0;
+}
 
 int main(int argc, char **argv)
 {
@@ -15,7 +101,7 @@ int main(int argc, char **argv)
 
 	setup_git_directory();
 	if (argc != 3 || get_sha1(argv[2], sha1))
-		usage("git-cat-file [-t|-s|-e|<type>] <sha1>");
+		usage("git-cat-file [-t|-s|-e|-p|<type>] <sha1>");
 
 	opt = 0;
 	if ( argv[1][0] == '-' ) {
@@ -43,6 +129,23 @@ int main(int argc, char **argv)
 	case 'e':
 		return !has_sha1_file(sha1);
 
+	case 'p':
+		if (get_sha1(argv[2], sha1) ||
+		    sha1_object_info(sha1, type, NULL))
+			die("Not a valid object name %s", argv[2]);
+
+		/* custom pretty-print here */
+		if (!strcmp(type, "tree"))
+			return execl_git_cmd("ls-tree", argv[2], NULL);
+
+		buf = read_sha1_file(sha1, type, &size);
+		if (!buf)
+			die("Cannot read object %s", argv[2]);
+		if (!strcmp(type, "tag"))
+			return pprint_tag(sha1, buf, size);
+
+		/* otherwise just spit out the data */
+		break;
 	case 0:
 		buf = read_object_with_reference(sha1, argv[1], &size, NULL);
 		break;
@@ -54,18 +157,6 @@ int main(int argc, char **argv)
 	if (!buf)
 		die("git-cat-file %s: bad file", argv[2]);
 
-	while (size > 0) {
-		long ret = xwrite(1, buf, size);
-		if (ret < 0) {
-			/* Ignore epipe */
-			if (errno == EPIPE)
-				break;
-			die("git-cat-file: %s", strerror(errno));
-		} else if (!ret) {
-			die("git-cat-file: disk full?");
-		}
-		size -= ret;
-		buf += ret;
-	}
+	flush_buffer(buf, size);
 	return 0;
 }

git-verify-tag.sh

@@ -4,9 +4,21 @@ USAGE='<tag>'
 SUBDIRECTORY_OK='Yes'
 . git-sh-setup
 
+verbose=
+while case $# in 0) break;; esac
+do
+	case "$1" in
+	-v|--v|--ve|--ver|--verb|--verbo|--verbos|--verbose)
+		verbose=t ;;
+	*)
+		break ;;
+	esac
+	shift
+done
+
 if [ "$#" != "1" ]
 then
-  usage
+	usage
 fi
 
 type="$(git-cat-file -t "$1" 2>/dev/null)" ||
@@ -15,6 +27,13 @@ type="$(git-cat-file -t "$1" 2>/dev/null)" ||
 test "$type" = tag ||
 	die "$1: cannot verify a non-tag object of type $type."
 
+case "$verbose" in
+t)
+	git-cat-file -p "$1" |
+	sed -n -e '/^-----BEGIN PGP SIGNATURE-----/q' -e p
+	;;
+esac
+
 git-cat-file tag "$1" >"$GIT_DIR/.tmp-vtag" || exit 1
 cat "$GIT_DIR/.tmp-vtag" |
 sed '/-----BEGIN PGP/Q' |