diff options
| -rw-r--r-- | read-cache.c | 58 |
1 files changed, 51 insertions, 7 deletions
diff --git a/read-cache.c b/read-cache.c index c159351eaf..1c173f7a63 100644 --- a/read-cache.c +++ b/read-cache.c @@ -12,6 +12,8 @@ #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); @@ -1236,6 +1238,7 @@ struct ondisk_cache_entry_extended { 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) @@ -1252,7 +1255,7 @@ static int verify_hdr(struct cache_header *hdr, unsigned long size) 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); @@ -1331,8 +1334,30 @@ static struct cache_entry *cache_entry_from_ondisk(struct ondisk_cache_entry *on 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; @@ -1357,10 +1382,22 @@ static struct cache_entry *create_from_disk(struct ondisk_cache_entry *ondisk, 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; } @@ -1373,6 +1410,7 @@ int read_index_from(struct index_state *istate, const char *path) struct cache_header *hdr; void *mmap; size_t mmap_size; + struct strbuf previous_name_buf = STRBUF_INIT, *previous_name; errno = EBUSY; if (istate->initialized) @@ -1410,6 +1448,11 @@ int read_index_from(struct index_state *istate, const char *path) istate->cache = xcalloc(istate->cache_alloc, sizeof(struct cache_entry *)); istate->initialized = 1; + if (hdr->hdr_version == htonl(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; @@ -1417,11 +1460,12 @@ int read_index_from(struct index_state *istate, const char *path) 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); |