From e0222159fa53ea24785cfb1dc5de0214e89b0117 Mon Sep 17 00:00:00 2001 From: Jonathan Nieder Date: Tue, 3 Oct 2017 19:39:54 -0700 Subject: strbuf doc: reuse after strbuf_release is fine 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 diff --git a/strbuf.h b/strbuf.h index 2075384..80112a8 100644 --- a/strbuf.h +++ b/strbuf.h @@ -82,8 +82,12 @@ extern char strbuf_slopbuf[]; extern void strbuf_init(struct strbuf *, size_t); /** - * Release a string buffer and the memory it used. You should not use the - * string buffer after using this function, unless you initialize it again. + * Release a string buffer and the memory it used. After this call, the + * strbuf points to an empty string that does not need to be free()ed, as + * if it had been set to `STRBUF_INIT` and never modified. + * + * To clear a strbuf in preparation for further use without the overhead + * of free()ing and malloc()ing again, use strbuf_reset() instead. */ extern void strbuf_release(struct strbuf *); @@ -91,6 +95,9 @@ extern void strbuf_release(struct strbuf *); * Detach the string from the strbuf and returns it; you now own the * storage the string occupies and it is your responsibility from then on * to release it with `free(3)` when you are done with it. + * + * The strbuf that previously held the string is reset to `STRBUF_INIT` so + * it can be reused after calling this function. */ extern char *strbuf_detach(struct strbuf *, size_t *); -- cgit v0.10.2-6-g49f6