diff options
Diffstat (limited to 'read-cache.c')
| -rw-r--r-- | read-cache.c | 105 |
1 files changed, 79 insertions, 26 deletions
diff --git a/read-cache.c b/read-cache.c index 50e094e053..1f71d12578 100644 --- a/read-cache.c +++ b/read-cache.c @@ -4,11 +4,26 @@ * Copyright (C) Linus Torvalds, 2005 */ #include "cache.h" +#include "cache-tree.h" + +/* Index extensions. + * + * The first letter should be 'A'..'Z' for extensions that are not + * necessary for a correct operation (i.e. optimization data). + * When new extensions are added that _needs_ to be understood in + * order to correctly interpret the index file, pick character that + * is outside the range, to cause the reader to abort. + */ + +#define CACHE_EXT(s) ( (s[0]<<24)|(s[1]<<16)|(s[2]<<8)|(s[3]) ) +#define CACHE_EXT_TREE 0x54524545 /* "TREE" */ struct cache_entry **active_cache = NULL; static time_t index_file_timestamp; unsigned int active_nr = 0, active_alloc = 0, active_cache_changed = 0; +struct cache_tree *active_cache_tree = NULL; + /* * This only updates the "non-critical" parts of the directory * cache, ie the parts that aren't tracked by GIT, and only used @@ -496,12 +511,10 @@ int add_cache_entry(struct cache_entry *ce, int option) return 0; } -static int verify_hdr(struct cache_header *hdr, unsigned long size, unsigned char *sha1) +static int verify_hdr(struct cache_header *hdr, unsigned long size) { SHA_CTX c; - unsigned char sha1_buf[20]; - if (!sha1) - sha1 = sha1_buf; + unsigned char sha1[20]; if (hdr->hdr_signature != htonl(CACHE_SIGNATURE)) return error("bad signature"); @@ -515,7 +528,23 @@ static int verify_hdr(struct cache_header *hdr, unsigned long size, unsigned cha return 0; } -int read_cache_1(unsigned char *cache_sha1) +static int read_index_extension(const char *ext, void *data, unsigned long sz) +{ + switch (CACHE_EXT(ext)) { + case CACHE_EXT_TREE: + active_cache_tree = cache_tree_read(data, sz); + break; + default: + if (*ext < 'A' || 'Z' < *ext) + return error("index uses %.4s extension, which we do not understand", + ext); + fprintf(stderr, "ignoring %.4s extension\n", ext); + break; + } + return 0; +} + +int read_cache(void) { int fd, i; struct stat st; @@ -549,7 +578,7 @@ int read_cache_1(unsigned char *cache_sha1) die("index file mmap failed (%s)", strerror(errno)); hdr = map; - if (verify_hdr(hdr, size, cache_sha1) < 0) + if (verify_hdr(hdr, size) < 0) goto unmap; active_nr = ntohl(hdr->hdr_entries); @@ -563,6 +592,22 @@ int read_cache_1(unsigned char *cache_sha1) active_cache[i] = ce; } index_file_timestamp = st.st_mtime; + while (offset <= size - 20 - 8) { + /* After an array of active_nr index entries, + * there can be arbitrary number of extended + * sections, each of which is prefixed with + * extension name (4-byte) and section length + * in 4-byte network byte order. + */ + unsigned long extsize; + memcpy(&extsize, map + offset + 4, 4); + extsize = ntohl(extsize); + if (read_index_extension(map + offset, + map + offset + 8, extsize) < 0) + goto unmap; + offset += 8; + offset += extsize; + } return active_nr; unmap: @@ -597,7 +642,18 @@ static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len) return 0; } -static int ce_flush(SHA_CTX *context, int fd, unsigned char *sha1) +static int write_index_ext_header(SHA_CTX *context, int fd, + unsigned long ext, unsigned long sz) +{ + ext = htonl(ext); + sz = htonl(sz); + if ((ce_write(context, fd, &ext, 4) < 0) || + (ce_write(context, fd, &sz, 4) < 0)) + return -1; + return 0; +} + +static int ce_flush(SHA_CTX *context, int fd) { unsigned int left = write_buffer_len; @@ -614,8 +670,7 @@ static int ce_flush(SHA_CTX *context, int fd, unsigned char *sha1) } /* Append the SHA1 signature at the end */ - SHA1_Final(sha1, context); - memcpy(write_buffer + left, sha1, 20); + SHA1_Final(write_buffer + left, context); left += 20; if (write(fd, write_buffer, left) != left) return -1; @@ -666,14 +721,11 @@ static void ce_smudge_racily_clean_entry(struct cache_entry *ce) } } -int write_cache_1(int newfd, struct cache_entry **cache, int entries, - unsigned char *cache_sha1) +int write_cache(int newfd, struct cache_entry **cache, int entries) { SHA_CTX c; struct cache_header hdr; int i, removed; - int status; - unsigned char sha1[20]; for (i = removed = 0; i < entries; i++) if (!cache[i]->ce_mode) @@ -697,18 +749,19 @@ int write_cache_1(int newfd, struct cache_entry **cache, int entries, if (ce_write(&c, newfd, ce, ce_size(ce)) < 0) return -1; } - status = ce_flush(&c, newfd, sha1); - if (cache_sha1) - memcpy(cache_sha1, sha1, 20); - return status; -} -int read_cache(void) -{ - return read_cache_1(NULL); -} - -int write_cache(int newfd, struct cache_entry **cache, int entries) -{ - return write_cache_1(newfd, cache, entries, NULL); + /* Write extension data here */ + if (active_cache_tree) { + unsigned long sz; + void *data = cache_tree_write(active_cache_tree, &sz); + if (data && + !write_index_ext_header(&c, newfd, CACHE_EXT_TREE, sz) && + !ce_write(&c, newfd, data, sz)) + ; + else { + free(data); + return -1; + } + } + return ce_flush(&c, newfd); } |