pretty: save commit encoding from logmsg_reencode if the caller needs it

The commit encoding is parsed by logmsg_reencode, there's no need for
the caller to re-parse it again. The reencoded message now has the new
encoding, not the original one. The caller would need to read commit
object again before parsing.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/blame.c

@@ -1425,7 +1425,7 @@ static void get_commit_info(struct commit *commit,
 	commit_info_init(ret);
 
 	encoding = get_log_output_encoding();
-	message = logmsg_reencode(commit, encoding);
+	message = logmsg_reencode(commit, NULL, encoding);
 	get_ac_line(message, "\nauthor ",
 		    &ret->author, &ret->author_mail,
 		    &ret->author_time, &ret->author_tz);

builtin/commit.c

@@ -955,7 +955,7 @@ static const char *read_commit_message(const char *name)
 	if (!commit)
 		die(_("could not lookup commit %s"), name);
 	out_enc = get_commit_output_encoding();
-	return logmsg_reencode(commit, out_enc);
+	return logmsg_reencode(commit, NULL, out_enc);
 }
 
 static int parse_and_validate_options(int argc, const char *argv[],

commit.h

@@ -101,6 +101,7 @@ struct userformat_want {
 extern int has_non_ascii(const char *text);
 struct rev_info; /* in revision.h, it circularly uses enum cmit_fmt */
 extern char *logmsg_reencode(const struct commit *commit,
+			     char **commit_encoding,
 			     const char *output_encoding);
 extern void logmsg_free(char *msg, const struct commit *commit);
 extern void get_commit_format(const char *arg, struct rev_info *);

pretty.c

@@ -594,6 +594,7 @@ static char *replace_encoding_header(char *buf, const char *encoding)
 }
 
 char *logmsg_reencode(const struct commit *commit,
+		      char **commit_encoding,
 		      const char *output_encoding)
 {
 	static const char *utf8 = "UTF-8";
@@ -615,9 +616,15 @@ char *logmsg_reencode(const struct commit *commit,
 			    sha1_to_hex(commit->object.sha1), typename(type));
 	}
 
-	if (!output_encoding || !*output_encoding)
+	if (!output_encoding || !*output_encoding) {
+		if (commit_encoding)
+			*commit_encoding =
+				get_header(commit, msg, "encoding");
 		return msg;
+	}
 	encoding = get_header(commit, msg, "encoding");
+	if (commit_encoding)
+		*commit_encoding = encoding;
 	use_encoding = encoding ? encoding : utf8;
 	if (same_encoding(use_encoding, output_encoding)) {
 		/*
@@ -658,7 +665,8 @@ char *logmsg_reencode(const struct commit *commit,
 	if (out)
 		out = replace_encoding_header(out, output_encoding);
 
-	free(encoding);
+	if (!commit_encoding)
+		free(encoding);
 	/*
 	 * If the re-encoding failed, out might be NULL here; in that
 	 * case we just return the commit message verbatim.
@@ -1288,7 +1296,7 @@ void format_commit_message(const struct commit *commit,
 	context.commit = commit;
 	context.pretty_ctx = pretty_ctx;
 	context.wrap_start = sb->len;
-	context.message = logmsg_reencode(commit, output_enc);
+	context.message = logmsg_reencode(commit, NULL, output_enc);
 
 	strbuf_expand(sb, format, format_commit_item, &context);
 	rewrap_message_tail(sb, &context, 0, 0, 0);
@@ -1451,7 +1459,7 @@ void pretty_print_commit(const struct pretty_print_context *pp,
 	}
 
 	encoding = get_log_output_encoding();
-	msg = reencoded = logmsg_reencode(commit, encoding);
+	msg = reencoded = logmsg_reencode(commit, NULL, encoding);
 
 	if (pp->fmt == CMIT_FMT_ONELINE || pp->fmt == CMIT_FMT_EMAIL)
 		indent = 0;

revision.c

@@ -2291,7 +2291,7 @@ static int commit_match(struct commit *commit, struct rev_info *opt)
 	 * in it.
 	 */
 	encoding = get_log_output_encoding();
-	message = logmsg_reencode(commit, encoding);
+	message = logmsg_reencode(commit, NULL, encoding);
 
 	/* Copy the commit to temporary if we are using "fake" headers */
 	if (buf.len)