builtin format-patch: squelch content-type for 7-bit ASCII

When --attach is not used, usually we do not say Content-Type:
and fluff, but if the commit message is not 7-bit ASCII, mark
it as "text/plain; charset=UTF-8".  This unclutters output
somewhat.

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

diff --git a/commit.c b/commit.c
index 7597fba70a8e96a029e3d84cf86289ffcb151223..94f470b75cfc68bfd8e14d1e421e19c5ad6004d6 100644 (file)
--- a/commit.c
+++ b/commit.c
@@ -559,10 +559,24 @@ unsigned long pretty_print_commit(enum cmit_fmt fmt, const struct commit *commit
        int indent = 4;
        int parents_shown = 0;
        const char *msg = commit->buffer;
+       int plain_non_ascii = 0;
 
        if (fmt == CMIT_FMT_ONELINE || fmt == CMIT_FMT_EMAIL)
                indent = 0;
 
+       /* After-subject is used to pass in Content-Type: multipart
+        * MIME header; in that case we do not have to do the
+        * plaintext content type even if the commit message has
+        * non 7-bit ASCII character.  Otherwise, check if we need
+        * to say this is not a 7-bit ASCII.
+        */
+       if (fmt == CMIT_FMT_EMAIL && !after_subject) {
+               int i;
+               for (i = 0; !plain_non_ascii && msg[i] && i < len; i++)
+                       if (msg[i] & 0x80)
+                               plain_non_ascii = 1;
+       }
+
        for (;;) {
                const char *line = msg;
                int linelen = get_one_line(msg, len);
@@ -648,13 +662,12 @@ unsigned long pretty_print_commit(enum cmit_fmt fmt, const struct commit *commit
                buf[offset++] = '\n';
                if (fmt == CMIT_FMT_ONELINE)
                        break;
-               if (subject) {
+               if (subject && plain_non_ascii) {
                        static const char header[] =
                                "Content-Type: text/plain; charset=UTF-8\n"
                                "Content-Transfer-Encoding: 8bit\n";
                        memcpy(buf + offset, header, sizeof(header)-1);
                        offset += sizeof(header)-1;
-                       subject = NULL;
                }
                if (after_subject) {
                        int slen = strlen(after_subject);