ident: rename commit_rewrite_person() to apply_mailmap_to_header()

commit_rewrite_person() takes a commit buffer and replaces the idents
in the header with their canonical versions using the mailmap mechanism.
The name "commit_rewrite_person()" is misleading as it doesn't convey
what kind of rewrite are we going to do to the buffer. It also doesn't
clearly mention that the function will limit itself to the header part
of the buffer. The new name, "apply_mailmap_to_header()", expresses the
functionality of the function pretty clearly.

We intend to use apply_mailmap_to_header() in git-cat-file to replace
idents in the headers of commit and tag object buffers. So, we will be
extending this function to take tag objects buffer as well and replace
idents on the tagger header using the mailmap mechanism.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: John Cai <johncai86@gmail.com>
Signed-off-by: Siddharth Asthana <siddharthasthana31@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

cache.h

@@ -1689,10 +1689,10 @@ struct ident_split {
 int split_ident_line(struct ident_split *, const char *, int);
 
 /*
- * Given a commit object buffer and the commit headers, replaces the idents
- * in the headers with their canonical versions using the mailmap mechanism.
+ * Given a commit or tag object buffer and the commit or tag headers, replaces
+ * the idents in the headers with their canonical versions using the mailmap mechanism.
  */
-void commit_rewrite_person(struct strbuf *, const char **, struct string_list *);
+void apply_mailmap_to_header(struct strbuf *, const char **, struct string_list *);
 
 /*
  * Compare split idents for equality or strict ordering. Note that we

ident.c

@@ -387,8 +387,8 @@ static ssize_t rewrite_ident_line(const char *person, size_t len,
 	return 0;
 }
 
-void commit_rewrite_person(struct strbuf *buf, const char **header,
-			    struct string_list *mailmap)
+void apply_mailmap_to_header(struct strbuf *buf, const char **header,
+			       struct string_list *mailmap)
 {
 	size_t buf_offset = 0;
 

revision.c

@@ -3792,7 +3792,7 @@ static int commit_match(struct commit *commit, struct rev_info *opt)
 		if (!buf.len)
 			strbuf_addstr(&buf, message);
 
-		commit_rewrite_person(&buf, commit_headers, opt->mailmap);
+		apply_mailmap_to_header(&buf, commit_headers, opt->mailmap);
 	}
 
 	/* Append "fake" message parts as needed */