[PATCH 2/3] untracked-cache: simplify parsing by dropping "next"
- From
Jeff King <peff@peff.net>
- Date
- Apr 18, 2019, 21:17 UTC
- Message-ID
- <20190418211738.GB18520@sigill.intra.peff.net>
- In-Reply-To
- <20190418211408.GA18011@sigill.intra.peff.net>
When we parse an on-disk untracked cache, we have two pointers, "data" and "next". As we parse, we point "next" to the end of an element, and then later update "data" to match.
But we actually don't need two pointers. Each parsing step can just update "data" directly from other variables we hold (and we don't have to worry about bailing in an intermediate state, since any parsing failure causes us to immediately discard "data" and return).
Signed-off-by: Jeff King <peff@peff.net> --- dir.c | 20 +++++++------------- 1 file changed, 7 insertions(+), 13 deletions(-)
diff --git a/dir.c b/dir.c index 7b0513c476..17865f44df 100644 --- a/dir.c +++ b/dir.c @@ -2732,50 +2732,44 @@ static int read_one_dir(struct untracked_cache_dir **untracked_, struct read_data *rd) { struct untracked_cache_dir ud, *untracked; - const unsigned char *next, *data = rd->data, *end = rd->end; + const unsigned char *data = rd->data, *end = rd->end; const unsigned char *eos; unsigned int value; int i, len; memset(&ud, 0, sizeof(ud)); - next = data; - value = decode_varint(&next); - if (next > end) + value = decode_varint(&data); + if (data > end) return -1; ud.recurse = 1; ud.untracked_alloc = value; ud.untracked_nr = value; if (ud.untracked_nr) ALLOC_ARRAY(ud.untracked, ud.untracked_nr); - data = next; - next = data; - ud.dirs_alloc = ud.dirs_nr = decode_varint(&next); - if (next > end) + ud.dirs_alloc = ud.dirs_nr = decode_varint(&data); + if (data > end) return -1; ALLOC_ARRAY(ud.dirs, ud.dirs_nr); - data = next; eos = memchr(data, '\0', end - data); if (!eos || eos == end) return -1; len = eos - data; - next = eos + 1; *untracked_ = untracked = xmalloc(st_add3(sizeof(*untracked), len, 1)); memcpy(untracked, &ud, sizeof(ud)); memcpy(untracked->name, data, len + 1); - data = next; + data = eos + 1; for (i = 0; i < untracked->untracked_nr; i++) { eos = memchr(data, '\0', end - data); if (!eos || eos == end) return -1; len = eos - data; - next = eos + 1; untracked->untracked[i] = xmemdupz(data, len); - data = next; + data = eos + 1; } rd->ucd[rd->index++] = untracked;
-- 2.21.0.1092.g8b0302e9c4