On Sun, Feb 09, 2020 at 12:36:22PM -0500, Eric Sunshine wrote:
> On Sun, Feb 9, 2020 at 8:45 AM René Scharfe <l.s.r@xxxxxx> wrote:
> > Add a function for inserting a C string into a strbuf. Use it
> > throughout the source to get rid of magic string length constants and
> > explicit strlen() calls.
> >
> > Like strbuf_addstr(), implement it as an inline function to avoid the
> > implicit strlen() calls to cause runtime overhead.
> >
> > Signed-off-by: René Scharfe <l.s.r@xxxxxx>
> > ---
> > diff --git a/mailinfo.c b/mailinfo.c
> > @@ -570,7 +570,7 @@ static int check_header(struct mailinfo *mi,
> > len = strlen("Content-Type: ");
> > strbuf_add(&sb, line->buf + len, line->len - len);
> > decode_header(mi, &sb);
> > - strbuf_insert(&sb, 0, "Content-Type: ", len);
> > + strbuf_insertstr(&sb, 0, "Content-Type: ");
> > handle_content_type(mi, &sb);
>
> Meh. We've already computed the length of "Content-Type: " a few lines
> earlier, so taking advantage of that value when inserting the string
> literal is perfectly sensible. Thus, I'm not convinced that this
> change is an improvement.
I had a similar thought. I kind of wonder if all of these "len" bits
(and their repeated strings) could go away if cmp_header() just used
skip_iprefix() under the hood and had a pointer out-parameter.
Something like the (largely untested) patch below. That would also make
it easy to support arbitrary amounts of whitespace after the header,
which I think are allowed by the standard (whereas now we'd parse
"Content-type: text/plain" as " text/plain", which is silly).
Worth doing?
---
diff --git a/mailinfo.c b/mailinfo.c
index b395adbdf2..bbb5b429f8 100644
--- a/mailinfo.c
+++ b/mailinfo.c
@@ -346,11 +346,16 @@ static const char *header[MAX_HDR_PARSED] = {
"From","Subject","Date",
};
-static inline int cmp_header(const struct strbuf *line, const char *hdr)
+static inline int cmp_header(const struct strbuf *line, const char *hdr,
+ const char **outval)
{
- int len = strlen(hdr);
- return !strncasecmp(line->buf, hdr, len) && line->len > len &&
- line->buf[len] == ':' && isspace(line->buf[len + 1]);
+ const char *val;
+ if (!skip_iprefix(line->buf, hdr, &val) ||
+ *val++ != ':' ||
+ !isspace(*val++))
+ return 0;
+ *outval = val;
+ return 1;
}
static int is_format_patch_separator(const char *line, int len)
@@ -547,17 +552,17 @@ static int check_header(struct mailinfo *mi,
const struct strbuf *line,
struct strbuf *hdr_data[], int overwrite)
{
- int i, ret = 0, len;
+ int i, ret = 0;
struct strbuf sb = STRBUF_INIT;
+ const char *val;
/* search for the interesting parts */
for (i = 0; header[i]; i++) {
- int len = strlen(header[i]);
- if ((!hdr_data[i] || overwrite) && cmp_header(line, header[i])) {
+ if ((!hdr_data[i] || overwrite) && cmp_header(line, header[i], &val)) {
/* Unwrap inline B and Q encoding, and optionally
* normalize the meta information to utf8.
*/
- strbuf_add(&sb, line->buf + len + 2, line->len - len - 2);
+ strbuf_addstr(&sb, val);
decode_header(mi, &sb);
handle_header(&hdr_data[i], &sb);
ret = 1;
@@ -566,26 +571,22 @@ static int check_header(struct mailinfo *mi,
}
/* Content stuff */
- if (cmp_header(line, "Content-Type")) {
- len = strlen("Content-Type: ");
- strbuf_add(&sb, line->buf + len, line->len - len);
+ if (cmp_header(line, "Content-Type", &val)) {
+ strbuf_addstr(&sb, val);
decode_header(mi, &sb);
- strbuf_insert(&sb, 0, "Content-Type: ", len);
handle_content_type(mi, &sb);
ret = 1;
goto check_header_out;
}
- if (cmp_header(line, "Content-Transfer-Encoding")) {
- len = strlen("Content-Transfer-Encoding: ");
- strbuf_add(&sb, line->buf + len, line->len - len);
+ if (cmp_header(line, "Content-Transfer-Encoding", &val)) {
+ strbuf_addstr(&sb, val);
decode_header(mi, &sb);
handle_content_transfer_encoding(mi, &sb);
ret = 1;
goto check_header_out;
}
- if (cmp_header(line, "Message-Id")) {
- len = strlen("Message-Id: ");
- strbuf_add(&sb, line->buf + len, line->len - len);
+ if (cmp_header(line, "Message-Id", &val)) {
+ strbuf_addstr(&sb, val);
decode_header(mi, &sb);
if (mi->add_message_id)
mi->message_id = strbuf_detach(&sb, NULL);
@@ -607,8 +608,9 @@ static int is_inbody_header(const struct mailinfo *mi,
const struct strbuf *line)
{
int i;
+ const char *val;
for (i = 0; header[i]; i++)
- if (!mi->s_hdr_data[i] && cmp_header(line, header[i]))
+ if (!mi->s_hdr_data[i] && cmp_header(line, header[i], &val))
return 1;
return 0;
}
