read_packed_refs(): use mmap to read the `packed-refs` file
It's still done in a pretty stupid way, involving more data copying than necessary. That will improve in future commits. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Michael Haggerty committed
Sep 13, 2017 at 19:15 UTC
49a03ef46667ad5074f1e602e392b7763c686205
1 file changed
+32
-10
refs/packed-backend.c
+32
-10
@@ -215,8 +215,12 @@ static NORETURN void die_invalid_line(const char *path,
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*/
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static struct packed_ref_cache *read_packed_refs(struct packed_ref_store *refs)
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{
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- FILE *f;
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struct packed_ref_cache *packed_refs = xcalloc(1, sizeof(*packed_refs));
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+ int fd;
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+ struct stat st;
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+ size_t size;
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+ char *buf;
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+ const char *pos, *eol, *eof;
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struct ref_entry *last = NULL;
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struct strbuf line = STRBUF_INIT;
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enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
@@ -227,8 +231,8 @@ static struct packed_ref_cache *read_packed_refs(struct packed_ref_store *refs)
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packed_refs->cache = create_ref_cache(NULL, NULL);
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packed_refs->cache->root->flag &= ~REF_INCOMPLETE;
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- f = fopen(refs->path, "r");
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- if (!f) {
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+ fd = open(refs->path, O_RDONLY);
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+ if (fd < 0) {
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if (errno == ENOENT) {
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/*
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* This is OK; it just means that no
@@ -241,16 +245,27 @@ static struct packed_ref_cache *read_packed_refs(struct packed_ref_store *refs)
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}
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}
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- stat_validity_update(&packed_refs->validity, fileno(f));
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+ stat_validity_update(&packed_refs->validity, fd);
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+
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+ if (fstat(fd, &st) < 0)
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+ die_errno("couldn't stat %s", refs->path);
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+
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+ size = xsize_t(st.st_size);
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+ buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
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+ pos = buf;
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+ eof = buf + size;
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dir = get_ref_dir(packed_refs->cache->root);
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- while (strbuf_getwholeline(&line, f, '\n') != EOF) {
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+ while (pos < eof) {
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struct object_id oid;
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const char *refname;
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const char *traits;
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- if (!line.len || line.buf[line.len - 1] != '\n')
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- die_unterminated_line(refs->path, line.buf, line.len);
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+ eol = memchr(pos, '\n', eof - pos);
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+ if (!eol)
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+ die_unterminated_line(refs->path, pos, eof - pos);
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+
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+ strbuf_add(&line, pos, eol + 1 - pos);
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if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
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if (strstr(traits, " fully-peeled "))
@@ -258,7 +273,7 @@ static struct packed_ref_cache *read_packed_refs(struct packed_ref_store *refs)
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else if (strstr(traits, " peeled "))
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peeled = PEELED_TAGS;
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/* perhaps other traits later as well */
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- continue;
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+ goto next_line;
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}
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refname = parse_ref_line(&line, &oid);
@@ -291,11 +306,18 @@ static struct packed_ref_cache *read_packed_refs(struct packed_ref_store *refs)
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} else {
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die_invalid_line(refs->path, line.buf, line.len);
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}
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+
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+ next_line:
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+ /* The "+ 1" is for the LF character. */
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+ pos = eol + 1;
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+ strbuf_reset(&line);
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}
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- fclose(f);
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- strbuf_release(&line);
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+ if (munmap(buf, size))
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+ die_errno("error ummapping packed-refs file");
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+ close(fd);
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+ strbuf_release(&line);
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return packed_refs;
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}
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