Split index file version specific functionality to their own functions,
to prepare for moving the index file version specific parts to their own
file. This makes it easier to add a new index file format later.
Signed-off-by: Thomas Gummerer <t.gumme...@gmail.com>
---
cache.h | 5 +-
read-cache.c | 130 +++++++++++++++++++++++++++++++++------------------
test-index-version.c | 2 +-
3 files changed, 90 insertions(+), 47 deletions(-)
diff --git a/cache.h b/cache.h
index c288678..7af853b 100644
--- a/cache.h
+++ b/cache.h
@@ -100,9 +100,12 @@ unsigned long git_deflate_bound(git_zstream *, unsigned
long);
*/
#define CACHE_SIGNATURE 0x44495243 /* "DIRC" */
-struct cache_header {
+struct cache_version_header {
unsigned int hdr_signature;
unsigned int hdr_version;
+};
+
+struct cache_header {
unsigned int hdr_entries;
};
diff --git a/read-cache.c b/read-cache.c
index d5201f9..93947bf 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1268,10 +1268,8 @@ struct ondisk_cache_entry_extended {
ondisk_cache_entry_extended_size(ce_namelen(ce)) : \
ondisk_cache_entry_size(ce_namelen(ce)))
-static int verify_hdr(struct cache_header *hdr, unsigned long size)
+static int verify_hdr_version(struct cache_version_header *hdr, unsigned long
size)
{
- git_SHA_CTX c;
- unsigned char sha1[20];
int hdr_version;
if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
@@ -1279,10 +1277,22 @@ static int verify_hdr(struct cache_header *hdr,
unsigned long size)
hdr_version = ntohl(hdr->hdr_version);
if (hdr_version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < hdr_version)
return error("bad index version %d", hdr_version);
+ return 0;
+}
+
+static int verify_hdr(void *mmap, unsigned long size)
+{
+ git_SHA_CTX c;
+ unsigned char sha1[20];
+
+ if (size < sizeof(struct cache_version_header)
+ + sizeof(struct cache_header) + 20)
+ die("index file smaller than expected");
+
git_SHA1_Init(&c);
- git_SHA1_Update(&c, hdr, size - 20);
+ git_SHA1_Update(&c, mmap, size - 20);
git_SHA1_Final(sha1, &c);
- if (hashcmp(sha1, (unsigned char *)hdr + size - 20))
+ if (hashcmp(sha1, (unsigned char *)mmap + size - 20))
return error("bad index file sha1 signature");
return 0;
}
@@ -1424,47 +1434,19 @@ static struct cache_entry *create_from_disk(struct
ondisk_cache_entry *ondisk,
return ce;
}
-/* remember to discard_cache() before reading a different cache! */
-int read_index_from(struct index_state *istate, const char *path)
+static int read_index_v2(struct index_state *istate, void *mmap, unsigned long
mmap_size)
{
- int fd, i;
- struct stat st;
+ int i;
unsigned long src_offset;
- struct cache_header *hdr;
- void *mmap;
- size_t mmap_size;
+ struct cache_version_header *hdr;
+ struct cache_header *hdr_v2;
struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
- if (istate->initialized)
- return istate->cache_nr;
-
- istate->timestamp.sec = 0;
- istate->timestamp.nsec = 0;
- fd = open(path, O_RDONLY);
- if (fd < 0) {
- if (errno == ENOENT)
- return 0;
- die_errno("index file open failed");
- }
-
- if (fstat(fd, &st))
- die_errno("cannot stat the open index");
-
- mmap_size = xsize_t(st.st_size);
- if (mmap_size < sizeof(struct cache_header) + 20)
- die("index file smaller than expected");
-
- mmap = xmmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd,
0);
- if (mmap == MAP_FAILED)
- die_errno("unable to map index file");
- close(fd);
-
hdr = mmap;
- if (verify_hdr(hdr, mmap_size) < 0)
- goto unmap;
+ hdr_v2 = (struct cache_header *)((char *)mmap + sizeof(*hdr));
istate->version = ntohl(hdr->hdr_version);
- istate->cache_nr = ntohl(hdr->hdr_entries);
+ istate->cache_nr = ntohl(hdr_v2->hdr_entries);
istate->cache_alloc = alloc_nr(istate->cache_nr);
istate->cache = xcalloc(istate->cache_alloc, sizeof(*istate->cache));
istate->initialized = 1;
@@ -1474,7 +1456,7 @@ int read_index_from(struct index_state *istate, const
char *path)
else
previous_name = NULL;
- src_offset = sizeof(*hdr);
+ src_offset = sizeof(*hdr) + sizeof(*hdr_v2);
for (i = 0; i < istate->cache_nr; i++) {
struct ondisk_cache_entry *disk_ce;
struct cache_entry *ce;
@@ -1487,8 +1469,6 @@ int read_index_from(struct index_state *istate, const
char *path)
src_offset += consumed;
}
strbuf_release(&previous_name_buf);
- istate->timestamp.sec = st.st_mtime;
- istate->timestamp.nsec = ST_MTIME_NSEC(st);
while (src_offset <= mmap_size - 20 - 8) {
/* After an array of active_nr index entries,
@@ -1508,6 +1488,58 @@ int read_index_from(struct index_state *istate, const
char *path)
src_offset += 8;
src_offset += extsize;
}
+ return 0;
+unmap:
+ munmap(mmap, mmap_size);
+ die("index file corrupt");
+}
+
+/* remember to discard_cache() before reading a different cache! */
+int read_index_from(struct index_state *istate, const char *path)
+{
+ int fd;
+ struct stat st;
+ struct cache_version_header *hdr;
+ void *mmap;
+ size_t mmap_size;
+
+ errno = EBUSY;
+ if (istate->initialized)
+ return istate->cache_nr;
+
+ errno = ENOENT;
+ istate->timestamp.sec = 0;
+ istate->timestamp.nsec = 0;
+ fd = open(path, O_RDONLY);
+ if (fd < 0) {
+ if (errno == ENOENT)
+ return 0;
+ die_errno("index file open failed");
+ }
+
+ if (fstat(fd, &st))
+ die_errno("cannot stat the open index");
+
+ errno = EINVAL;
+ mmap_size = xsize_t(st.st_size);
+ if (mmap_size < sizeof(struct cache_header) + 20)
+ die("index file smaller than expected");
+
+ mmap = xmmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd,
0);
+ close(fd);
+ if (mmap == MAP_FAILED)
+ die_errno("unable to map index file");
+
+ hdr = mmap;
+ if (verify_hdr_version(hdr, mmap_size) < 0)
+ goto unmap;
+
+ if (verify_hdr(mmap, mmap_size) < 0)
+ goto unmap;
+
+ read_index_v2(istate, mmap, mmap_size);
+ istate->timestamp.sec = st.st_mtime;
+ istate->timestamp.nsec = ST_MTIME_NSEC(st);
munmap(mmap, mmap_size);
return istate->cache_nr;
@@ -1771,10 +1803,11 @@ void update_index_if_able(struct index_state *istate,
struct lock_file *lockfile
rollback_lock_file(lockfile);
}
-int write_index(struct index_state *istate, int newfd)
+static int write_index_v2(struct index_state *istate, int newfd)
{
git_SHA_CTX c;
- struct cache_header hdr;
+ struct cache_version_header hdr;
+ struct cache_header hdr_v2;
int i, err, removed, extended, hdr_version;
struct cache_entry **cache = istate->cache;
int entries = istate->cache_nr;
@@ -1804,11 +1837,13 @@ int write_index(struct index_state *istate, int newfd)
hdr.hdr_signature = htonl(CACHE_SIGNATURE);
hdr.hdr_version = htonl(hdr_version);
- hdr.hdr_entries = htonl(entries - removed);
+ hdr_v2.hdr_entries = htonl(entries - removed);
git_SHA1_Init(&c);
if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
return -1;
+ if (ce_write(&c, newfd, &hdr_v2, sizeof(hdr_v2)) < 0)
+ return -1;
previous_name = (hdr_version == 4) ? &previous_name_buf : NULL;
for (i = 0; i < entries; i++) {
@@ -1854,6 +1889,11 @@ int write_index(struct index_state *istate, int newfd)
return 0;
}
+int write_index(struct index_state *istate, int newfd)
+{
+ return write_index_v2(istate, newfd);
+}
+
/*
* Read the index file that is potentially unmerged into given
* index_state, dropping any unmerged entries. Returns true if
diff --git a/test-index-version.c b/test-index-version.c
index 05d4699..4c0386f 100644
--- a/test-index-version.c
+++ b/test-index-version.c
@@ -2,7 +2,7 @@
int main(int argc, char **argv)
{
- struct cache_header hdr;
+ struct cache_version_header hdr;
int version;
memset(&hdr,0,sizeof(hdr));
--
1.8.3.453.g1dfc63d
--
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