pretty.c: add %f format specifier to format_commit_message()

This specifier represents the sanitized and filename friendly subject
line of a commit. No checks are made against the length of the string,
so users may need to trim the result to the desired length if using as a
filename. This is commonly used by format-patch to massage commit
subjects into filenames and output patches to files.

Signed-off-by: Stephen Boyd <bebarino@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/pretty-formats.txt b/Documentation/pretty-formats.txt
index 5c6e678aa3d9e75570d5a5578e38b0a45bae720e..2a845b1e57590a6f18f05fd3efa858b736c1071a 100644 (file)
--- a/Documentation/pretty-formats.txt
+++ b/Documentation/pretty-formats.txt
@@ -121,6 +121,7 @@ The placeholders are:
 - '%d': ref names, like the --decorate option of linkgit:git-log[1]
 - '%e': encoding
 - '%s': subject
+- '%f': sanitized subject line, suitable for a filename
 - '%b': body
 - '%Cred': switch color to red
 - '%Cgreen': switch color to green

diff --git a/pretty.c b/pretty.c
index efa70245f19ef3493cd701ea20505203a466d65e..c57cef47c93912a709fc67fe98cdcff15ed34dc6 100644 (file)
--- a/pretty.c
+++ b/pretty.c
@@ -493,6 +493,38 @@ static void parse_commit_header(struct format_commit_context *context)
        context->commit_header_parsed = 1;
 }
 
+static int istitlechar(char c)
+{
+       return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') ||
+               (c >= '0' && c <= '9') || c == '.' || c == '_';
+}
+
+static void format_sanitized_subject(struct strbuf *sb, const char *msg)
+{
+       size_t trimlen;
+       int space = 2;
+
+       for (; *msg && *msg != '\n'; msg++) {
+               if (istitlechar(*msg)) {
+                       if (space == 1)
+                               strbuf_addch(sb, '-');
+                       space = 0;
+                       strbuf_addch(sb, *msg);
+                       if (*msg == '.')
+                               while (*(msg+1) == '.')
+                                       msg++;
+               } else
+                       space |= 1;
+       }
+
+       /* trim any trailing '.' or '-' characters */
+       trimlen = 0;
+       while (sb->buf[sb->len - 1 - trimlen] == '.'
+               || sb->buf[sb->len - 1 - trimlen] == '-')
+               trimlen++;
+       strbuf_remove(sb, sb->len - trimlen, trimlen);
+}
+
 const char *format_subject(struct strbuf *sb, const char *msg,
                           const char *line_separator)
 {
@@ -683,6 +715,9 @@ static size_t format_commit_item(struct strbuf *sb, const char *placeholder,
        case 's':       /* subject */
                format_subject(sb, msg + c->subject_off, " ");
                return 1;
+       case 'f':       /* sanitized subject */
+               format_sanitized_subject(sb, msg + c->subject_off);
+               return 1;
        case 'b':       /* body */
                strbuf_addstr(sb, msg + c->body_off);
                return 1;