#include "commit.h"
#include "blob.h"
#include "resolve-undo.h"
+#include "strbuf.h"
+#include "varint.h"
static struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really);
return 0;
}
-static int is_empty_blob_sha1(const unsigned char *sha1)
-{
- static const unsigned char empty_blob_sha1[20] = {
- 0xe6,0x9d,0xe2,0x9b,0xb2,0xd1,0xd6,0x43,0x4b,0x8b,
- 0x29,0xae,0x77,0x5a,0xd8,0xc2,0xe4,0x8c,0x53,0x91
- };
-
- return !hashcmp(sha1, empty_blob_sha1);
-}
-
static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st)
{
unsigned int changed = 0;
* Index File I/O
*****************************************************************/
+#define INDEX_FORMAT_DEFAULT 3
+
/*
* dev/ino/uid/gid/size are also just tracked to the low 32 bits
* Again - this is just a (very strong in practice) heuristic that
char name[FLEX_ARRAY]; /* more */
};
+/* These are only used for v3 or lower */
#define align_flex_name(STRUCT,len) ((offsetof(struct STRUCT,name) + (len) + 8) & ~7)
#define ondisk_cache_entry_size(len) align_flex_name(ondisk_cache_entry,len)
#define ondisk_cache_entry_extended_size(len) align_flex_name(ondisk_cache_entry_extended,len)
if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
return error("bad signature");
hdr_version = ntohl(hdr->hdr_version);
- if (hdr_version < 2 || 3 < hdr_version)
+ if (hdr_version < 2 || 4 < hdr_version)
return error("bad index version %d", hdr_version);
git_SHA1_Init(&c);
git_SHA1_Update(&c, hdr, size - 20);
return ce;
}
+/*
+ * Adjacent cache entries tend to share the leading paths, so it makes
+ * sense to only store the differences in later entries. In the v4
+ * on-disk format of the index, each on-disk cache entry stores the
+ * number of bytes to be stripped from the end of the previous name,
+ * and the bytes to append to the result, to come up with its name.
+ */
+static unsigned long expand_name_field(struct strbuf *name, const char *cp_)
+{
+ const unsigned char *ep, *cp = (const unsigned char *)cp_;
+ size_t len = decode_varint(&cp);
+
+ if (name->len < len)
+ die("malformed name field in the index");
+ strbuf_remove(name, name->len - len, len);
+ for (ep = cp; *ep; ep++)
+ ; /* find the end */
+ strbuf_add(name, cp, ep - cp);
+ return (const char *)ep + 1 - cp_;
+}
+
static struct cache_entry *create_from_disk(struct ondisk_cache_entry *ondisk,
- unsigned long *ent_size)
+ unsigned long *ent_size,
+ struct strbuf *previous_name)
{
struct cache_entry *ce;
size_t len;
else
name = ondisk->name;
- if (len == CE_NAMEMASK)
- len = strlen(name);
- ce = cache_entry_from_ondisk(ondisk, flags, name, len);
- *ent_size = ondisk_ce_size(ce);
+ if (!previous_name) {
+ /* v3 and earlier */
+ if (len == CE_NAMEMASK)
+ len = strlen(name);
+ ce = cache_entry_from_ondisk(ondisk, flags, name, len);
+
+ *ent_size = ondisk_ce_size(ce);
+ } else {
+ unsigned long consumed;
+ consumed = expand_name_field(previous_name, name);
+ ce = cache_entry_from_ondisk(ondisk, flags,
+ previous_name->buf,
+ previous_name->len);
+
+ *ent_size = (name - ((char *)ondisk)) + consumed;
+ }
return ce;
}
struct cache_header *hdr;
void *mmap;
size_t mmap_size;
+ struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
errno = EBUSY;
if (istate->initialized)
if (verify_hdr(hdr, mmap_size) < 0)
goto unmap;
+ istate->version = ntohl(hdr->hdr_version);
istate->cache_nr = ntohl(hdr->hdr_entries);
istate->cache_alloc = alloc_nr(istate->cache_nr);
istate->cache = xcalloc(istate->cache_alloc, sizeof(struct cache_entry *));
istate->initialized = 1;
+ if (istate->version == 4)
+ previous_name = &previous_name_buf;
+ else
+ previous_name = NULL;
+
src_offset = sizeof(*hdr);
for (i = 0; i < istate->cache_nr; i++) {
struct ondisk_cache_entry *disk_ce;
unsigned long consumed;
disk_ce = (struct ondisk_cache_entry *)((char *)mmap + src_offset);
- ce = create_from_disk(disk_ce, &consumed);
+ ce = create_from_disk(disk_ce, &consumed, previous_name);
set_index_entry(istate, i, ce);
src_offset += consumed;
}
+ strbuf_release(&previous_name_buf);
istate->timestamp.sec = st.st_mtime;
istate->timestamp.nsec = ST_MTIME_NSEC(st);
}
}
-static int ce_write_entry(git_SHA_CTX *c, int fd, struct cache_entry *ce)
+/* Copy miscellaneous fields but not the name */
+static char *copy_cache_entry_to_ondisk(struct ondisk_cache_entry *ondisk,
+ struct cache_entry *ce)
{
- int size = ondisk_ce_size(ce);
- struct ondisk_cache_entry *ondisk = xcalloc(1, size);
- char *name;
- int result;
-
ondisk->ctime.sec = htonl(ce->ce_ctime.sec);
ondisk->mtime.sec = htonl(ce->ce_mtime.sec);
ondisk->ctime.nsec = htonl(ce->ce_ctime.nsec);
struct ondisk_cache_entry_extended *ondisk2;
ondisk2 = (struct ondisk_cache_entry_extended *)ondisk;
ondisk2->flags2 = htons((ce->ce_flags & CE_EXTENDED_FLAGS) >> 16);
- name = ondisk2->name;
+ return ondisk2->name;
+ }
+ else {
+ return ondisk->name;
+ }
+}
+
+static int ce_write_entry(git_SHA_CTX *c, int fd, struct cache_entry *ce,
+ struct strbuf *previous_name)
+{
+ int size;
+ struct ondisk_cache_entry *ondisk;
+ char *name;
+ int result;
+
+ if (!previous_name) {
+ size = ondisk_ce_size(ce);
+ ondisk = xcalloc(1, size);
+ name = copy_cache_entry_to_ondisk(ondisk, ce);
+ memcpy(name, ce->name, ce_namelen(ce));
+ } else {
+ int common, to_remove, prefix_size;
+ unsigned char to_remove_vi[16];
+ for (common = 0;
+ (ce->name[common] &&
+ common < previous_name->len &&
+ ce->name[common] == previous_name->buf[common]);
+ common++)
+ ; /* still matching */
+ to_remove = previous_name->len - common;
+ prefix_size = encode_varint(to_remove, to_remove_vi);
+
+ if (ce->ce_flags & CE_EXTENDED)
+ size = offsetof(struct ondisk_cache_entry_extended, name);
+ else
+ size = offsetof(struct ondisk_cache_entry, name);
+ size += prefix_size + (ce_namelen(ce) - common + 1);
+
+ ondisk = xcalloc(1, size);
+ name = copy_cache_entry_to_ondisk(ondisk, ce);
+ memcpy(name, to_remove_vi, prefix_size);
+ memcpy(name + prefix_size, ce->name + common, ce_namelen(ce) - common);
+
+ strbuf_splice(previous_name, common, to_remove,
+ ce->name + common, ce_namelen(ce) - common);
}
- else
- name = ondisk->name;
- memcpy(name, ce->name, ce_namelen(ce));
result = ce_write(c, fd, ondisk, size);
free(ondisk);
{
git_SHA_CTX c;
struct cache_header hdr;
- int i, err, removed, extended;
+ int i, err, removed, extended, hdr_version;
struct cache_entry **cache = istate->cache;
int entries = istate->cache_nr;
struct stat st;
+ struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
for (i = removed = extended = 0; i < entries; i++) {
if (cache[i]->ce_flags & CE_REMOVE)
}
}
+ if (!istate->version)
+ istate->version = INDEX_FORMAT_DEFAULT;
+
+ /* demote version 3 to version 2 when the latter suffices */
+ if (istate->version == 3 || istate->version == 2)
+ istate->version = extended ? 3 : 2;
+
+ hdr_version = istate->version;
+
hdr.hdr_signature = htonl(CACHE_SIGNATURE);
- /* for extended format, increase version so older git won't try to read it */
- hdr.hdr_version = htonl(extended ? 3 : 2);
+ hdr.hdr_version = htonl(hdr_version);
hdr.hdr_entries = htonl(entries - removed);
git_SHA1_Init(&c);
if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
return -1;
+ previous_name = (hdr_version == 4) ? &previous_name_buf : NULL;
for (i = 0; i < entries; i++) {
struct cache_entry *ce = cache[i];
if (ce->ce_flags & CE_REMOVE)
continue;
if (!ce_uptodate(ce) && is_racy_timestamp(istate, ce))
ce_smudge_racily_clean_entry(ce);
- if (ce_write_entry(&c, newfd, ce) < 0)
+ if (ce_write_entry(&c, newfd, ce, previous_name) < 0)
return -1;
}
+ strbuf_release(&previous_name_buf);
/* Write extension data here */
if (istate->cache_tree) {