[PATCH 1/3] --pretty=format: parse commit message only once
- From
René Scharfe <rene.scharfe@lsrfire.ath.cx>
- Date
- Nov 10, 2007, 11:14 UTC
- Message-ID
- <4735928C.3040009@lsrfire.ath.cx>
- In-Reply-To
- <20071110004635.GA14992@sigill.intra.peff.net>
As Jeff King pointed out, some placeholder expansions are related to each other: the steps to calculate one go most of the way towards calculating the other, too.
This patch makes format_commit_message() parse the commit message only once, remembering the position of each item. This speeds up handling of format strings containing multiple placeholders from the set %s, %a*, %c*, %e, %b.
Here are the timings for the git version in next. The first one is to estimate the overhead of the caching, the second one is taken from http://svn.tue.mpg.de/tentakel/trunk/tentakel/Makefile as an example of a format string found in the wild. The times are the fastest of three consecutive runs in each case:
$ time git log --pretty=format:%e >/dev/null
real 0m0.381s user 0m0.340s sys 0m0.024s
$ time git log --pretty=format:"* %cd %cn%n%n%s%n%b" >/dev/null
real 0m0.623s user 0m0.556s sys 0m0.052s
And here the times with this patch:
$ time git log --pretty=format:%e >/dev/null
real 0m0.385s user 0m0.332s sys 0m0.040s
$ time git log --pretty=format:"* %cd %cn%n%n%s%n%b" >/dev/null
real 0m0.563s user 0m0.504s sys 0m0.048s
Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx> --- pretty.c | 124 +++++++++++++++++++++++++++++++++++++++++--------------------- 1 files changed, 82 insertions(+), 42 deletions(-)
diff --git a/pretty.c b/pretty.c index 9fbd73f..0c2f83b 100644 --- a/pretty.c +++ b/pretty.c @@ -354,14 +354,67 @@ static void format_person_part(struct strbuf *sb, char part, } } -static void format_commit_item(struct strbuf *sb, const char *placeholder, - void *context) +struct chunk { + size_t off; + size_t len; +}; + +struct format_commit_context { + const struct commit *commit; + + /* These offsets are relative to the start of the commit message. */ + int commit_header_parsed; + struct chunk subject; + struct chunk author; + struct chunk committer; + struct chunk encoding; + size_t body_off; +}; + +static void parse_commit_header(struct format_commit_context *context) { - const struct commit *commit = context; - struct commit_list *p; + const char *msg = context->commit->buffer; int i; enum { HEADER, SUBJECT, BODY } state; + + for (i = 0, state = HEADER; msg[i] && state < BODY; i++) { + int eol; + for (eol = i; msg[eol] && msg[eol] != '\n'; eol++) + ; /* do nothing */ + + if (state == SUBJECT) { + context->subject.off = i; + context->subject.len = eol - i; + i = eol; + } + if (i == eol) { + state++; + /* strip empty lines */ + while (msg[eol + 1] == '\n') + eol++; + } else if (!prefixcmp(msg + i, "author ")) { + context->author.off = i + 7; + context->author.len = eol - i - 7; + } else if (!prefixcmp(msg + i, "committer ")) { + context->committer.off = i + 10; + context->committer.len = eol - i - 10; + } else if (!prefixcmp(msg + i, "encoding ")) { + context->encoding.off = i + 9; + context->encoding.len = eol - i - 9; + } + i = eol; + } + context->body_off = i; + context->commit_header_parsed = 1; +} + +static void format_commit_item(struct strbuf *sb, const char *placeholder, + void *context) +{ + struct format_commit_context *c = context; + const struct commit *commit = c->commit; const char *msg = commit->buffer; + struct commit_list *p; /* these are independent of the commit */ switch (placeholder[0]) { @@ -429,45 +482,28 @@ static void format_commit_item(struct strbuf *sb, const char *placeholder, } /* For the rest we have to parse the commit header. */ - for (i = 0, state = HEADER; msg[i] && state < BODY; i++) { - int eol; - for (eol = i; msg[eol] && msg[eol] != '\n'; eol++) - ; /* do nothing */ + if (!c->commit_header_parsed) + parse_commit_header(c); - if (state == SUBJECT) { - if (placeholder[0] == 's') { - strbuf_add(sb, msg + i, eol - i); - return; - } - i = eol; - } - if (i == eol) { - state++; - /* strip empty lines */ - while (msg[eol + 1] == '\n') - eol++; - } else if (!prefixcmp(msg + i, "author ")) { - if (placeholder[0] == 'a') { - format_person_part(sb, placeholder[1], - msg + i + 7, eol - i - 7); - return; - } - } else if (!prefixcmp(msg + i, "committer ")) { - if (placeholder[0] == 'c') { - format_person_part(sb, placeholder[1], - msg + i + 10, eol - i - 10); - return; - } - } else if (!prefixcmp(msg + i, "encoding ")) { - if (placeholder[0] == 'e') { - strbuf_add(sb, msg + i + 9, eol - i - 9); - return; - } - } - i = eol; + switch (placeholder[0]) { + case 's': + strbuf_add(sb, msg + c->subject.off, c->subject.len); + return; + case 'a': + format_person_part(sb, placeholder[1], + msg + c->author.off, c->author.len); + return; + case 'c': + format_person_part(sb, placeholder[1], + msg + c->committer.off, c->committer.len); + return; + case 'e': + strbuf_add(sb, msg + c->encoding.off, c->encoding.len); + return; + case 'b': + strbuf_addstr(sb, msg + c->body_off); + return; } - if (msg[i] && placeholder[0] == 'b') /* body */ - strbuf_addstr(sb, msg + i); } void format_commit_message(const struct commit *commit, @@ -505,7 +541,11 @@ void format_commit_message(const struct commit *commit, "m", /* left/right/bottom */ NULL }; - strbuf_expand(sb, format, placeholders, format_commit_item, (void *)commit); + struct format_commit_context context; + + memset(&context, 0, sizeof(context)); + context.commit = commit; + strbuf_expand(sb, format, placeholders, format_commit_item, &context); } static void pp_header(enum cmit_fmt fmt,
-- 1.5.3.5.1651.g30bf