git/strbuf.h, branch v2.16.2

strbuf: remove unused stripspace function alias

2017-12-05T16:50:15Z

In commit 63af4a8446 ("strbuf: make stripspace() part of strbuf", 2015-10-16), stripspace() was moved to strbuf and renamed to strbuf_stripspace(). A "temporary" alias was added for the old name until all topic branches had time to switch over. They have had time, so remove the old alias. Signed-off-by: Elijah Newren Signed-off-by: Junio C Hamano

Merge branch 'jn/strbuf-doc-re-reuse'

2017-10-07T07:27:53Z

* jn/strbuf-doc-re-reuse: strbuf doc: reuse after strbuf_release is fine

strbuf doc: reuse after strbuf_release is fine

2017-10-04T06:21:52Z

strbuf_release leaves the strbuf in a valid, initialized state, so there is no need to call strbuf_init after it. Moreover, this is not likely to change in the future: strbuf_release leaving the strbuf in a valid state has been easy to maintain and has been very helpful for Git's robustness and simplicity (e.g., preventing use-after-free vulnerabilities). Document the semantics so the next generation of Git developers can become familiar with them without reading the implementation. It is still not advisable to call strbuf_release too often because it is wasteful, so add a note pointing to strbuf_reset for that. The same semantics apply to strbuf_detach. Add a similar note to its docstring to make that clear. Improved-by: Jeff King Signed-off-by: Jonathan Nieder Signed-off-by: Junio C Hamano

Merge branch 'ma/ts-cleanups'

2017-09-10T08:08:22Z

Assorted bugfixes and clean-ups. * ma/ts-cleanups: ThreadSanitizer: add suppressions strbuf_setlen: don't write to strbuf_slopbuf pack-objects: take lock before accessing `remaining` convert: always initialize attr_action in convert_attrs

strbuf_setlen: don't write to strbuf_slopbuf

2017-08-23T17:38:46Z

strbuf_setlen(., 0) writes '\0' to sb.buf[0], where buf is either allocated and unique to sb, or the global slopbuf. The slopbuf is meant to provide a guarantee that buf is not NULL and that a freshly initialized buffer contains the empty string, but it is not supposed to be written to. That strbuf_setlen writes to slopbuf has at least two implications: First, it's wrong in principle. Second, it might be hiding misuses which are just waiting to wreak havoc. Third, ThreadSanitizer detects a race when multiple threads write to slopbuf at roughly the same time, thus potentially making any more critical races harder to spot. Avoid writing to strbuf_slopbuf in strbuf_setlen. Let's instead assert on the first byte of slopbuf being '\0', since it helps ensure the promised invariant of buf[len] == '\0'. (We know that "len" was already 0, or someone has messed with "alloc". If someone has fiddled with the fields that much beyond the correct interface, they're on their own.) This is a function which is used in many places, possibly also in hot code paths. There are two branches in strbuf_setlen already, and we are adding a third and possibly a fourth (in the assert). In hot code paths, we hopefully reuse the buffer in order to avoid continous reallocations. Thus, after a start-up phase, we should always take the same path, which might help branch prediction, and we would never make the assert. If a hot code path continuously reallocates, we probably have bigger performance problems than this new safety-check. Simple measurements do not contradict this reasoning. 100000000 times resetting a buffer and adding the empty string takes 5.29/5.26 seconds with/without this patch (best of three). Releasing at every iteration yields 18.01/17.87. Adding a 30-character string instead of the empty string yields 5.61/5.58 and 17.28/17.28(!). This patch causes the git binary emitted by gcc 5.4.0 -O2 on my machine to grow from 11389848 bytes to 11497184 bytes, an increase of 0.9%. I also tried to piggy-back on the fact that we already check alloc, which should already tell us whether we are using the slopbuf: if (sb->alloc) { if (len > sb->alloc - 1) die("BUG: strbuf_setlen() beyond buffer"); sb->buf[len] = '\0'; } else { if (len) die("BUG: strbuf_setlen() beyond buffer"); assert(!strbuf_slopbuf[0]); } sb->len = len; That didn't seem to be much slower (5.38, 18.02, 5.70, 17.32 seconds), but it does introduce some minor code duplication. The resulting git binary was 11510528 bytes large (another 0.1% increase). Signed-off-by: Martin Ågren Signed-off-by: Junio C Hamano

strbuf: use designated initializers in STRBUF_INIT

2017-07-14T15:32:44Z

There are certain C99 features that might be nice to use in our code base, but we've hesitated to do so in order to avoid breaking compatibility with older compilers. But we don't actually know if people are even using pre-C99 compilers these days. One way to figure that out is to introduce a very small use of a feature, and see if anybody complains. The strbuf code is a good place to do this for a few reasons: - it always gets compiled, no matter which Makefile knobs have been tweaked. - it's very stable; this definition hasn't changed in a long time and is not likely to (so if we have to revert, it's unlikely to cause headaches) If this patch can survive a few releases without complaint, then we can feel more confident that designated initializers are widely supported by our user base. It also is an indication that other C99 features may be supported, but not a guarantee (e.g., gcc had designated initializers before C99 existed). And if we do get complaints, then we'll have gained some data and we can easily revert this patch. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

Merge branch 'ab/strbuf-addftime-tzname-boolify'

2017-07-07T01:14:47Z

strbuf_addftime() is further getting tweaked. * ab/strbuf-addftime-tzname-boolify: strbuf: change an always NULL/"" strbuf_addftime() param to bool strbuf.h comment: discuss strbuf_addftime() arguments in order

strbuf: change an always NULL/"" strbuf_addftime() param to bool

2017-07-01T17:47:05Z

strbuf_addftime() allows callers to pass a time zone name for expanding %Z. The only current caller either passes the empty string or NULL, in which case %Z is handed over verbatim to strftime(3). Replace that string parameter with a flag controlling whether to remove %Z from the format specification. This simplifies the code. Commit-message-by: René Scharfe Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Junio C Hamano

Merge branch 'rs/pretty-add-again'

2017-06-24T21:28:38Z

The pretty-format specifiers like '%h', '%t', etc. had an optimization that no longer works correctly. In preparation/hope of getting it correctly implemented, first discard the optimization that is broken. * rs/pretty-add-again: pretty: recalculate duplicate short hashes

strbuf.h comment: discuss strbuf_addftime() arguments in order

2017-06-24T18:15:59Z

Change the comment documenting the strbuf_addftime() function to discuss the parameters in the order in which they appear, which makes this easier to read than discussing them out of order. Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Junio C Hamano