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Merge branch 'nd/narrow' (early part) into jc/add-i-t-a
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* 'nd/narrow' (early part):
  Extend index to save more flags
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Junio C Hamano committed Nov 29, 2008
2 parents d5cbdba + 06aaaa0 commit fe60dff
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Showing 2 changed files with 95 additions and 14 deletions.
58 changes: 54 additions & 4 deletions cache.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -115,6 +115,26 @@ struct ondisk_cache_entry {
char name[FLEX_ARRAY]; /* more */
};

/*
* This struct is used when CE_EXTENDED bit is 1
* The struct must match ondisk_cache_entry exactly from
* ctime till flags
*/
struct ondisk_cache_entry_extended {
struct cache_time ctime;
struct cache_time mtime;
unsigned int dev;
unsigned int ino;
unsigned int mode;
unsigned int uid;
unsigned int gid;
unsigned int size;
unsigned char sha1[20];
unsigned short flags;
unsigned short flags2;
char name[FLEX_ARRAY]; /* more */
};

struct cache_entry {
unsigned int ce_ctime;
unsigned int ce_mtime;
Expand All @@ -136,7 +156,15 @@ struct cache_entry {
#define CE_VALID (0x8000)
#define CE_STAGESHIFT 12

/* In-memory only */
/*
* Range 0xFFFF0000 in ce_flags is divided into
* two parts: in-memory flags and on-disk ones.
* Flags in CE_EXTENDED_FLAGS will get saved on-disk
* if you want to save a new flag, add it in
* CE_EXTENDED_FLAGS
*
* In-memory only flags
*/
#define CE_UPDATE (0x10000)
#define CE_REMOVE (0x20000)
#define CE_UPTODATE (0x40000)
Expand All @@ -145,6 +173,24 @@ struct cache_entry {
#define CE_HASHED (0x100000)
#define CE_UNHASHED (0x200000)

/*
* Extended on-disk flags
*/
/* CE_EXTENDED2 is for future extension */
#define CE_EXTENDED2 0x80000000

#define CE_EXTENDED_FLAGS (0)

/*
* Safeguard to avoid saving wrong flags:
* - CE_EXTENDED2 won't get saved until its semantic is known
* - Bits in 0x0000FFFF have been saved in ce_flags already
* - Bits in 0x003F0000 are currently in-memory flags
*/
#if CE_EXTENDED_FLAGS & 0x803FFFFF
#error "CE_EXTENDED_FLAGS out of range"
#endif

/*
* Copy the sha1 and stat state of a cache entry from one to
* another. But we never change the name, or the hash state!
Expand Down Expand Up @@ -177,7 +223,9 @@ static inline size_t ce_namelen(const struct cache_entry *ce)
}

#define ce_size(ce) cache_entry_size(ce_namelen(ce))
#define ondisk_ce_size(ce) ondisk_cache_entry_size(ce_namelen(ce))
#define ondisk_ce_size(ce) (((ce)->ce_flags & CE_EXTENDED) ? \
ondisk_cache_entry_extended_size(ce_namelen(ce)) : \
ondisk_cache_entry_size(ce_namelen(ce)))
#define ce_stage(ce) ((CE_STAGEMASK & (ce)->ce_flags) >> CE_STAGESHIFT)
#define ce_uptodate(ce) ((ce)->ce_flags & CE_UPTODATE)
#define ce_mark_uptodate(ce) ((ce)->ce_flags |= CE_UPTODATE)
Expand Down Expand Up @@ -220,8 +268,10 @@ static inline int ce_to_dtype(const struct cache_entry *ce)
(S_ISREG(mode) ? (S_IFREG | ce_permissions(mode)) : \
S_ISLNK(mode) ? S_IFLNK : S_ISDIR(mode) ? S_IFDIR : S_IFGITLINK)

#define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7)
#define ondisk_cache_entry_size(len) ((offsetof(struct ondisk_cache_entry,name) + (len) + 8) & ~7)
#define flexible_size(STRUCT,len) ((offsetof(struct STRUCT,name) + (len) + 8) & ~7)
#define cache_entry_size(len) flexible_size(cache_entry,len)
#define ondisk_cache_entry_size(len) flexible_size(ondisk_cache_entry,len)
#define ondisk_cache_entry_extended_size(len) flexible_size(ondisk_cache_entry_extended,len)

struct index_state {
struct cache_entry **cache;
Expand Down
51 changes: 41 additions & 10 deletions read-cache.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1098,7 +1098,7 @@ static int verify_hdr(struct cache_header *hdr, unsigned long size)

if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
return error("bad signature");
if (hdr->hdr_version != htonl(2))
if (hdr->hdr_version != htonl(2) && hdr->hdr_version != htonl(3))
return error("bad index version");
git_SHA1_Init(&c);
git_SHA1_Update(&c, hdr, size - 20);
Expand Down Expand Up @@ -1133,6 +1133,7 @@ int read_index(struct index_state *istate)
static void convert_from_disk(struct ondisk_cache_entry *ondisk, struct cache_entry *ce)
{
size_t len;
const char *name;

ce->ce_ctime = ntohl(ondisk->ctime.sec);
ce->ce_mtime = ntohl(ondisk->mtime.sec);
Expand All @@ -1145,19 +1146,31 @@ static void convert_from_disk(struct ondisk_cache_entry *ondisk, struct cache_en
/* On-disk flags are just 16 bits */
ce->ce_flags = ntohs(ondisk->flags);

/* For future extension: we do not understand this entry yet */
if (ce->ce_flags & CE_EXTENDED)
die("Unknown index entry format");
hashcpy(ce->sha1, ondisk->sha1);

len = ce->ce_flags & CE_NAMEMASK;

if (ce->ce_flags & CE_EXTENDED) {
struct ondisk_cache_entry_extended *ondisk2;
int extended_flags;
ondisk2 = (struct ondisk_cache_entry_extended *)ondisk;
extended_flags = ntohs(ondisk2->flags2) << 16;
/* We do not yet understand any bit out of CE_EXTENDED_FLAGS */
if (extended_flags & ~CE_EXTENDED_FLAGS)
die("Unknown index entry format %08x", extended_flags);
ce->ce_flags |= extended_flags;
name = ondisk2->name;
}
else
name = ondisk->name;

if (len == CE_NAMEMASK)
len = strlen(ondisk->name);
len = strlen(name);
/*
* NEEDSWORK: If the original index is crafted, this copy could
* go unchecked.
*/
memcpy(ce->name, ondisk->name, len + 1);
memcpy(ce->name, name, len + 1);
}

static inline size_t estimate_cache_size(size_t ondisk_size, unsigned int entries)
Expand Down Expand Up @@ -1422,6 +1435,7 @@ static int ce_write_entry(git_SHA_CTX *c, int fd, struct cache_entry *ce)
{
int size = ondisk_ce_size(ce);
struct ondisk_cache_entry *ondisk = xcalloc(1, size);
char *name;

ondisk->ctime.sec = htonl(ce->ce_ctime);
ondisk->ctime.nsec = 0;
Expand All @@ -1435,7 +1449,15 @@ static int ce_write_entry(git_SHA_CTX *c, int fd, struct cache_entry *ce)
ondisk->size = htonl(ce->ce_size);
hashcpy(ondisk->sha1, ce->sha1);
ondisk->flags = htons(ce->ce_flags);
memcpy(ondisk->name, ce->name, ce_namelen(ce));
if (ce->ce_flags & CE_EXTENDED) {
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;
}
else
name = ondisk->name;
memcpy(name, ce->name, ce_namelen(ce));

return ce_write(c, fd, ondisk, size);
}
Expand All @@ -1444,16 +1466,25 @@ int write_index(const struct index_state *istate, int newfd)
{
git_SHA_CTX c;
struct cache_header hdr;
int i, err, removed;
int i, err, removed, extended;
struct cache_entry **cache = istate->cache;
int entries = istate->cache_nr;

for (i = removed = 0; i < entries; i++)
for (i = removed = extended = 0; i < entries; i++) {
if (cache[i]->ce_flags & CE_REMOVE)
removed++;

/* reduce extended entries if possible */
cache[i]->ce_flags &= ~CE_EXTENDED;
if (cache[i]->ce_flags & CE_EXTENDED_FLAGS) {
extended++;
cache[i]->ce_flags |= CE_EXTENDED;
}
}

hdr.hdr_signature = htonl(CACHE_SIGNATURE);
hdr.hdr_version = htonl(2);
/* for extended format, increase version so older git won't try to read it */
hdr.hdr_version = htonl(extended ? 3 : 2);
hdr.hdr_entries = htonl(entries - removed);

git_SHA1_Init(&c);
Expand Down

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