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clean up pack index handling a bit

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Especially with the new index format to come, it is more appropriate
to encapsulate more into check_packed_git_idx() and assume less of the
index format in struct packed_git.

To that effect, the index_base is renamed to index_data with void * type
so it is not used directly but other pointers initialized with it. This
allows for a couple pointer cast removal, as well as providing a better
generic name to grep for when adding support for new index versions or
formats.

And index_data is declared const too while at it.

(based on commit 4287307833)

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Nicolas Pitre
2008-07-16 02:31:35 -04:00
committed by Junio C Hamano
parent 8977c110b5
commit c86a54b714
6 changed files with 110 additions and 69 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
builtin-pack-objects.c
View File

@@ -170,11 +170,12 @@ static void prepare_pack_revindex(struct pack_revindex *rix)
struct packed_git *p = rix->p;
int num_ent = num_packed_objects(p);
int i;
void *index = p->index_base + 256;
const char *index = p->index_data;
index += 4 * 256;
rix->revindex = xmalloc(sizeof(*rix->revindex) * (num_ent + 1));
for (i = 0; i < num_ent; i++) {
unsigned int hl = *((unsigned int *)((char *) index + 24*i));
uint32_t hl = *((uint32_t *)(index + 24 * i));
rix->revindex[i].offset = ntohl(hl);
rix->revindex[i].nr = i;
}
@@ -222,11 +223,11 @@ static unsigned long find_packed_object_size(struct packed_git *p,
return entry[1].offset - ofs;
}
static unsigned char *find_packed_object_name(struct packed_git *p,
unsigned long ofs)
static const unsigned char *find_packed_object_name(struct packed_git *p,
unsigned long ofs)
{
struct revindex_entry *entry = find_packed_object(p, ofs);
return (unsigned char *)(p->index_base + 256) + 24 * entry->nr + 4;
return ((unsigned char *)p->index_data) + 4 * 256 + 24 * entry->nr + 4;
}
static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
@@ -959,7 +960,8 @@ static void check_object(struct object_entry *entry)
* delta.
*/
if (!no_reuse_delta) {
unsigned char c, *base_name;
unsigned char c;
const unsigned char *base_name;
unsigned long ofs;
/* there is at least 20 bytes left in the pack */
switch (entry->in_pack_type) {

5
cache.h
View File

@@ -334,8 +334,9 @@ extern struct packed_git {
struct packed_git *next;
unsigned long index_size;
unsigned long pack_size;
unsigned int *index_base;
const void *index_data;
void *pack_base;
int index_version;
unsigned int pack_last_used;
unsigned int pack_use_cnt;
int pack_local;
@@ -374,7 +375,7 @@ extern int server_supports(const char *feature);
extern struct packed_git *parse_pack_index(unsigned char *sha1);
extern struct packed_git *parse_pack_index_file(const unsigned char *sha1,
char *idx_path);
const char *idx_path);
extern void prepare_packed_git(void);
extern void reprepare_packed_git(void);

8
pack-check.c
View File

@@ -6,7 +6,7 @@
static int verify_packfile(struct packed_git *p)
{
unsigned long index_size = p->index_size;
void *index_base = p->index_base;
const unsigned char *index_base = p->index_data;
SHA_CTX ctx;
unsigned char sha1[20];
struct pack_header *hdr;
@@ -42,7 +42,7 @@ static int verify_packfile(struct packed_git *p)
if (hashcmp(sha1, (unsigned char *)(p->pack_base) + p->pack_size - 20))
return error("Packfile %s SHA1 mismatch with itself",
p->pack_name);
if (hashcmp(sha1, (unsigned char *)index_base + index_size - 40))
if (hashcmp(sha1, index_base + index_size - 40))
return error("Packfile %s SHA1 mismatch with idx",
p->pack_name);
@@ -136,7 +136,7 @@ static void show_pack_info(struct packed_git *p)
int verify_pack(struct packed_git *p, int verbose)
{
unsigned long index_size = p->index_size;
void *index_base = p->index_base;
const unsigned char *index_base = p->index_data;
SHA_CTX ctx;
unsigned char sha1[20];
int ret;
@@ -146,7 +146,7 @@ int verify_pack(struct packed_git *p, int verbose)
SHA1_Init(&ctx);
SHA1_Update(&ctx, index_base, index_size - 20);
SHA1_Final(sha1, &ctx);
if (hashcmp(sha1, (unsigned char *)index_base + index_size - 20))
if (hashcmp(sha1, index_base + index_size - 20))
ret = error("Packfile index for %s SHA1 mismatch",
p->pack_name);

30
pack-redundant.c
View File

@@ -17,7 +17,7 @@ static int load_all_packs, verbose, alt_odb;
struct llist_item {
struct llist_item *next;
unsigned char *sha1;
const unsigned char *sha1;
};
static struct llist {
struct llist_item *front;
@@ -104,9 +104,9 @@ static struct llist * llist_copy(struct llist *list)
return ret;
}
static inline struct llist_item * llist_insert(struct llist *list,
struct llist_item *after,
unsigned char *sha1)
static inline struct llist_item *llist_insert(struct llist *list,
struct llist_item *after,
const unsigned char *sha1)
{
struct llist_item *new = llist_item_get();
new->sha1 = sha1;
@@ -128,12 +128,14 @@ static inline struct llist_item * llist_insert(struct llist *list,
return new;
}
static inline struct llist_item *llist_insert_back(struct llist *list, unsigned char *sha1)
static inline struct llist_item *llist_insert_back(struct llist *list,
const unsigned char *sha1)
{
return llist_insert(list, list->back, sha1);
}
static inline struct llist_item *llist_insert_sorted_unique(struct llist *list, unsigned char *sha1, struct llist_item *hint)
static inline struct llist_item *llist_insert_sorted_unique(struct llist *list,
const unsigned char *sha1, struct llist_item *hint)
{
struct llist_item *prev = NULL, *l;
@@ -246,12 +248,12 @@ static struct pack_list * pack_list_difference(const struct pack_list *A,
static void cmp_two_packs(struct pack_list *p1, struct pack_list *p2)
{
int p1_off, p2_off;
unsigned char *p1_base, *p2_base;
const unsigned char *p1_base, *p2_base;
struct llist_item *p1_hint = NULL, *p2_hint = NULL;
p1_off = p2_off = 256 * 4 + 4;
p1_base = (unsigned char *) p1->pack->index_base;
p2_base = (unsigned char *) p2->pack->index_base;
p1_base = p1->pack->index_data;
p2_base = p2->pack->index_data;
while (p1_off <= p1->pack->index_size - 3 * 20 &&
p2_off <= p2->pack->index_size - 3 * 20)
@@ -351,11 +353,11 @@ static size_t sizeof_union(struct packed_git *p1, struct packed_git *p2)
{
size_t ret = 0;
int p1_off, p2_off;
unsigned char *p1_base, *p2_base;
const unsigned char *p1_base, *p2_base;
p1_off = p2_off = 256 * 4 + 4;
p1_base = (unsigned char *)p1->index_base;
p2_base = (unsigned char *)p2->index_base;
p1_base = p1->index_data;
p2_base = p2->index_data;
while (p1_off <= p1->index_size - 3 * 20 &&
p2_off <= p2->index_size - 3 * 20)
@@ -534,7 +536,7 @@ static struct pack_list * add_pack(struct packed_git *p)
{
struct pack_list l;
size_t off;
unsigned char *base;
const unsigned char *base;
if (!p->pack_local && !(alt_odb || verbose))
return NULL;
@@ -543,7 +545,7 @@ static struct pack_list * add_pack(struct packed_git *p)
llist_init(&l.all_objects);
off = 256 * 4 + 4;
base = (unsigned char *)p->index_base;
base = p->index_data;
while (off <= p->index_size - 3 * 20) {
llist_insert_back(l.all_objects, base + off);
off += 24;

28
pack.h
View File

@@ -15,5 +15,33 @@ struct pack_header {
unsigned int hdr_entries;
};
/*
* The first four bytes of index formats later than version 1 should
* start with this signature, as all older git binaries would find this
* value illegal and abort reading the file.
*
* This is the case because the number of objects in a packfile
* cannot exceed 1,431,660,000 as every object would need at least
* 3 bytes of data and the overall packfile cannot exceed 4 GiB with
* version 1 of the index file due to the offsets limited to 32 bits.
* Clearly the signature exceeds this maximum.
*
* Very old git binaries will also compare the first 4 bytes to the
* next 4 bytes in the index and abort with a "non-monotonic index"
* error if the second 4 byte word is smaller than the first 4
* byte word. This would be true in the proposed future index
* format as idx_signature would be greater than idx_version.
*/
#define PACK_IDX_SIGNATURE 0xff744f63 /* "\377tOc" */
/*
* Packed object index header
*/
struct pack_idx_header {
uint32_t idx_signature;
uint32_t idx_version;
};
extern int verify_pack(struct packed_git *, int);
#endif

94
sha1_file.c
View File

@@ -402,15 +402,15 @@ static int pack_used_ctr;
static unsigned long pack_mapped;
struct packed_git *packed_git;
static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
void **idx_map_)
static int check_packed_git_idx(const char *path, struct packed_git *p)
{
void *idx_map;
unsigned int *index;
struct pack_idx_header *hdr;
unsigned long idx_size;
int nr, i;
unsigned int nr, i, *index;
int fd = open(path, O_RDONLY);
struct stat st;
if (fd < 0)
return -1;
if (fstat(fd, &st)) {
@@ -423,14 +423,21 @@ static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
if (idx_map == MAP_FAILED)
return -1;
index = idx_map;
*idx_map_ = idx_map;
*idx_size_ = idx_size;
/* a future index format would start with this, as older git
* binaries would fail the non-monotonic index check below.
* give a nicer warning to the user if we can.
*/
hdr = idx_map;
if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
munmap(idx_map, idx_size);
return error("index file %s is a newer version"
" and is not supported by this binary"
" (try upgrading GIT to a newer version)",
path);
}
/* check index map */
if (idx_size < 4*256 + 20 + 20)
return error("index file too small");
nr = 0;
index = idx_map;
for (i = 0; i < 256; i++) {
unsigned int n = ntohl(index[i]);
if (n < nr)
@@ -448,6 +455,9 @@ static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
if (idx_size != 4*256 + nr * 24 + 20 + 20)
return error("wrong index file size");
p->index_version = 1;
p->index_data = idx_map;
p->index_size = idx_size;
return 0;
}
@@ -521,7 +531,7 @@ int use_packed_git(struct packed_git *p)
/* Check if the pack file matches with the index file.
* this is cheap.
*/
if (hashcmp((unsigned char *)(p->index_base) +
if (hashcmp((unsigned char *)(p->index_data) +
p->index_size - 40,
(unsigned char *)p->pack_base +
p->pack_size - 20)) {
@@ -536,35 +546,34 @@ int use_packed_git(struct packed_git *p)
struct packed_git *add_packed_git(char *path, int path_len, int local)
{
struct stat st;
struct packed_git *p;
unsigned long idx_size;
void *idx_map;
unsigned char sha1[20];
struct packed_git *p = xmalloc(sizeof(*p) + path_len + 2);
if (check_packed_git_idx(path, &idx_size, &idx_map))
/*
* Make sure a corresponding .pack file exists and that
* the index looks sane.
*/
path_len -= strlen(".idx");
if (path_len < 1)
return NULL;
/* do we have a corresponding .pack file? */
strcpy(path + path_len - 4, ".pack");
if (stat(path, &st) || !S_ISREG(st.st_mode)) {
munmap(idx_map, idx_size);
memcpy(p->pack_name, path, path_len);
strcpy(p->pack_name + path_len, ".pack");
if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode) ||
check_packed_git_idx(path, p)) {
free(p);
return NULL;
}
/* ok, it looks sane as far as we can check without
* actually mapping the pack file.
*/
p = xmalloc(sizeof(*p) + path_len + 2);
strcpy(p->pack_name, path);
p->index_size = idx_size;
p->pack_size = st.st_size;
p->index_base = idx_map;
p->next = NULL;
p->pack_base = NULL;
p->pack_last_used = 0;
p->pack_use_cnt = 0;
p->pack_local = local;
if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
hashcpy(p->sha1, sha1);
if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
hashclr(p->sha1);
return p;
}
@@ -574,23 +583,19 @@ struct packed_git *parse_pack_index(unsigned char *sha1)
return parse_pack_index_file(sha1, path);
}
struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
struct packed_git *parse_pack_index_file(const unsigned char *sha1,
const char *idx_path)
{
struct packed_git *p;
unsigned long idx_size;
void *idx_map;
char *path;
const char *path = sha1_pack_name(sha1);
struct packed_git *p = xmalloc(sizeof(*p) + strlen(path) + 2);
if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
if (check_packed_git_idx(idx_path, p)) {
free(p);
return NULL;
}
path = sha1_pack_name(sha1);
p = xmalloc(sizeof(*p) + strlen(path) + 2);
strcpy(p->pack_name, path);
p->index_size = idx_size;
p->pack_size = 0;
p->index_base = idx_map;
p->next = NULL;
p->pack_base = NULL;
p->pack_last_used = 0;
@@ -1175,24 +1180,27 @@ int num_packed_objects(const struct packed_git *p)
int nth_packed_object_sha1(const struct packed_git *p, int n,
unsigned char* sha1)
{
void *index = p->index_base + 256;
const unsigned char *index = p->index_data;
index += 4 * 256;
if (n < 0 || num_packed_objects(p) <= n)
return -1;
hashcpy(sha1, (unsigned char *) index + (24 * n) + 4);
hashcpy(sha1, index + 24 * n + 4);
return 0;
}
unsigned long find_pack_entry_one(const unsigned char *sha1,
struct packed_git *p)
{
unsigned int *level1_ofs = p->index_base;
const unsigned int *level1_ofs = p->index_data;
int hi = ntohl(level1_ofs[*sha1]);
int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
void *index = p->index_base + 256;
const unsigned char *index = p->index_data;
index += 4 * 256;
do {
int mi = (lo + hi) / 2;
int cmp = hashcmp((unsigned char *)index + (24 * mi) + 4, sha1);
int cmp = hashcmp(index + 24 * mi + 4, sha1);
if (!cmp)
return ntohl(*((unsigned int *) ((char *) index + (24 * mi))));
if (cmp > 0)