clean up calling conventions for pretty.c functions

We have a pretty_print_context representing the parameters
for a pretty-print session, but we did not use it uniformly.
As a result, functions kept growing more and more arguments.

Let's clean this up in a few ways:

  1. All pretty-print pp_* functions now take a context.
     This lets us reduce the number of arguments to these
     functions, since we were just passing around the
     context values separately.

  2. The context argument now has a cmit_fmt field, which
     was passed around separately. That's one less argument
     per function.

  3. The context argument always comes first, which makes
     calling a little more uniform.

This drops lines from some callers, and adds lines in a few
places (because we need an extra line to set the context's
fmt field). Overall, we don't save many lines, but the lines
that are there are a lot simpler and more readable.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/log.c

@@ -327,9 +327,11 @@ int cmd_whatchanged(int argc, const char **argv, const char *prefix)
 static void show_tagger(char *buf, int len, struct rev_info *rev)
 {
 	struct strbuf out = STRBUF_INIT;
+	struct pretty_print_context pp = {0};
 
-	pp_user_info("Tagger", rev->commit_format, &out, buf, rev->date_mode,
-		get_log_output_encoding());
+	pp.fmt = rev->commit_format;
+	pp.date_mode = rev->date_mode;
+	pp_user_info(&pp, "Tagger", &out, buf, get_log_output_encoding());
 	printf("%s", out.buf);
 	strbuf_release(&out);
 }
@@ -715,17 +717,16 @@ static void make_cover_letter(struct rev_info *rev, int use_stdout,
 			      int nr, struct commit **list, struct commit *head)
 {
 	const char *committer;
-	const char *subject_start = NULL;
 	const char *body = "*** SUBJECT HERE ***\n\n*** BLURB HERE ***\n";
 	const char *msg;
-	const char *extra_headers = rev->extra_headers;
 	struct shortlog log;
 	struct strbuf sb = STRBUF_INIT;
 	int i;
 	const char *encoding = "UTF-8";
 	struct diff_options opts;
 	int need_8bit_cte = 0;
 	struct commit *commit = NULL;
+	struct pretty_print_context pp = {0};
 
 	if (rev->commit_format != CMIT_FMT_EMAIL)
 		die("Cover letter needs email format");
@@ -757,19 +758,19 @@ static void make_cover_letter(struct rev_info *rev, int use_stdout,
 		free(commit);
 	}
 
-	log_write_email_headers(rev, head, &subject_start, &extra_headers,
+	log_write_email_headers(rev, head, &pp.subject, &pp.after_subject,
 				&need_8bit_cte);
 
 	for (i = 0; !need_8bit_cte && i < nr; i++)
 		if (has_non_ascii(list[i]->buffer))
 			need_8bit_cte = 1;
 
 	msg = body;
-	pp_user_info(NULL, CMIT_FMT_EMAIL, &sb, committer, DATE_RFC2822,
-		     encoding);
-	pp_title_line(CMIT_FMT_EMAIL, &msg, &sb, subject_start, extra_headers,
-		      encoding, need_8bit_cte);
-	pp_remainder(CMIT_FMT_EMAIL, &msg, &sb, 0);
+	pp.fmt = CMIT_FMT_EMAIL;
+	pp.date_mode = DATE_RFC2822;
+	pp_user_info(&pp, NULL, &sb, committer, encoding);
+	pp_title_line(&pp, &msg, &sb, encoding, need_8bit_cte);
+	pp_remainder(&pp, &msg, &sb, 0);
 	printf("%s\n", sb.buf);
 
 	strbuf_release(&sb);

builtin/merge.c

@@ -333,13 +333,14 @@ static void squash_message(void)
 
 	ctx.abbrev = rev.abbrev;
 	ctx.date_mode = rev.date_mode;
+	ctx.fmt = rev.commit_format;
 
 	strbuf_addstr(&out, "Squashed commit of the following:\n");
 	while ((commit = get_revision(&rev)) != NULL) {
 		strbuf_addch(&out, '\n');
 		strbuf_addf(&out, "commit %s\n",
 			sha1_to_hex(commit->object.sha1));
-		pretty_print_commit(rev.commit_format, commit, &out, &ctx);
+		pretty_print_commit(&ctx, commit, &out);
 	}
 	if (write(fd, out.buf, out.len) < 0)
 		die_errno("Writing SQUASH_MSG");

builtin/rev-list.c

@@ -108,7 +108,8 @@ static void show_commit(struct commit *commit, void *data)
 		struct pretty_print_context ctx = {0};
 		ctx.abbrev = revs->abbrev;
 		ctx.date_mode = revs->date_mode;
-		pretty_print_commit(revs->commit_format, commit, &buf, &ctx);
+		ctx.fmt = revs->commit_format;
+		pretty_print_commit(&ctx, commit, &buf);
 		if (revs->graph) {
 			if (buf.len) {
 				if (revs->commit_format != CMIT_FMT_ONELINE)

builtin/shortlog.c

@@ -161,11 +161,12 @@ void shortlog_add_commit(struct shortlog *log, struct commit *commit)
 		    sha1_to_hex(commit->object.sha1));
 	if (log->user_format) {
 		struct pretty_print_context ctx = {0};
+		ctx.fmt = CMIT_FMT_USERFORMAT;
 		ctx.abbrev = log->abbrev;
 		ctx.subject = "";
 		ctx.after_subject = "";
 		ctx.date_mode = DATE_NORMAL;
-		pretty_print_commit(CMIT_FMT_USERFORMAT, commit, &ufbuf, &ctx);
+		pretty_print_commit(&ctx, commit, &ufbuf);
 		buffer = ufbuf.buf;
 	} else if (*buffer) {
 		buffer++;

commit.h

@@ -70,6 +70,7 @@ enum cmit_fmt {
 
 struct pretty_print_context
 {
+	enum cmit_fmt fmt;
 	int abbrev;
 	const char *subject;
 	const char *after_subject;
@@ -95,22 +96,20 @@ extern void userformat_find_requirements(const char *fmt, struct userformat_want
 extern void format_commit_message(const struct commit *commit,
 				  const char *format, struct strbuf *sb,
 				  const struct pretty_print_context *context);
-extern void pretty_print_commit(enum cmit_fmt fmt, const struct commit *commit,
-				struct strbuf *sb,
-				const struct pretty_print_context *context);
+extern void pretty_print_commit(const struct pretty_print_context *pp,
+				const struct commit *commit,
+				struct strbuf *sb);
 extern void pp_commit_easy(enum cmit_fmt fmt, const struct commit *commit,
 			   struct strbuf *sb);
-void pp_user_info(const char *what, enum cmit_fmt fmt, struct strbuf *sb,
-		   const char *line, enum date_mode dmode,
-		   const char *encoding);
-void pp_title_line(enum cmit_fmt fmt,
+void pp_user_info(const struct pretty_print_context *pp,
+		  const char *what, struct strbuf *sb,
+		  const char *line, const char *encoding);
+void pp_title_line(const struct pretty_print_context *pp,
 		   const char **msg_p,
 		   struct strbuf *sb,
-		   const char *subject,
-		   const char *after_subject,
 		   const char *encoding,
 		   int need_8bit_cte);
-void pp_remainder(enum cmit_fmt fmt,
+void pp_remainder(const struct pretty_print_context *pp,
 		  const char **msg_p,
 		  struct strbuf *sb,
 		  int indent);

log-tree.c

@@ -505,7 +505,8 @@ void show_log(struct rev_info *opt)
 	ctx.abbrev = opt->diffopt.abbrev;
 	ctx.after_subject = extra_headers;
 	ctx.reflog_info = opt->reflog_info;
-	pretty_print_commit(opt->commit_format, commit, &msgbuf, &ctx);
+	ctx.fmt = opt->commit_format;
+	pretty_print_commit(&ctx, commit, &msgbuf);
 
 	if (opt->add_signoff)
 		append_signoff(&msgbuf, opt->add_signoff);