index: make the index file format extensible.
... and move the cache-tree data into it.
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/apply.c b/apply.c
index e283df3..acecf8d 100644
--- a/apply.c
+++ b/apply.c
@@ -12,10 +12,6 @@
#include "quote.h"
#include "blob.h"
-static unsigned char active_cache_sha1[20];
-static struct cache_tree *active_cache_tree;
-
-
// --check turns on checking that the working tree matches the
// files that are being modified, but doesn't apply the patch
// --stat does just a diffstat, and doesn't actually apply
@@ -1919,9 +1915,8 @@
if (write_index)
newfd = hold_index_file_for_update(&cache_file, get_index_file());
if (check_index) {
- if (read_cache_1(active_cache_sha1) < 0)
+ if (read_cache() < 0)
die("unable to read index file");
- active_cache_tree = read_cache_tree(active_cache_sha1);
}
if ((check || apply) && check_patch_list(list) < 0)
@@ -1931,11 +1926,9 @@
write_out_results(list, skipped_patch);
if (write_index) {
- if (write_cache_1(newfd, active_cache, active_nr,
- active_cache_sha1) ||
+ if (write_cache(newfd, active_cache, active_nr) ||
commit_index_file(&cache_file))
die("Unable to write new cachefile");
- write_cache_tree(active_cache_sha1, active_cache_tree);
}
if (show_index_info)
diff --git a/cache-tree.c b/cache-tree.c
index b34b0bc..2146723 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -11,16 +11,18 @@
return it;
}
-void cache_tree_free(struct cache_tree *it)
+void cache_tree_free(struct cache_tree **it_p)
{
int i;
+ struct cache_tree *it = *it_p;
if (!it)
return;
for (i = 0; i < it->subtree_nr; i++)
- cache_tree_free(it->down[i]->cache_tree);
+ cache_tree_free(&it->down[i]->cache_tree);
free(it->down);
free(it);
+ *it_p = NULL;
}
static struct cache_tree_sub *find_subtree(struct cache_tree *it,
@@ -78,7 +80,7 @@
break;
}
if (i < it->subtree_nr) {
- cache_tree_free(it->down[i]->cache_tree);
+ cache_tree_free(&it->down[i]->cache_tree);
free(it->down[i]);
/* 0 1 2 3 4 5
* ^ ^subtree_nr = 6
@@ -159,13 +161,27 @@
if (s->used)
down[dst++] = s;
else {
- cache_tree_free(s->cache_tree);
+ cache_tree_free(&s->cache_tree);
free(s);
it->subtree_nr--;
}
}
}
+int cache_tree_fully_valid(struct cache_tree *it)
+{
+ int i;
+ if (!it)
+ return 0;
+ if (it->entry_count < 0 || !has_sha1_file(it->sha1))
+ return 0;
+ for (i = 0; i < it->subtree_nr; i++) {
+ if (!cache_tree_fully_valid(it->down[i]->cache_tree))
+ return 0;
+ }
+ return 1;
+}
+
static int update_one(struct cache_tree *it,
struct cache_entry **cache,
int entries,
@@ -354,19 +370,15 @@
return buffer;
}
-static void *cache_tree_write(const unsigned char *cache_sha1,
- struct cache_tree *root,
- unsigned long *offset_p)
+void *cache_tree_write(struct cache_tree *root, unsigned long *size_p)
{
char path[PATH_MAX];
unsigned long size = 8192;
char *buffer = xmalloc(size);
- /* the cache checksum of the corresponding index file. */
- memcpy(buffer, cache_sha1, 20);
- *offset_p = 20;
+ *size_p = 0;
path[0] = 0;
- return write_one(root, path, 0, buffer, &size, offset_p);
+ return write_one(root, path, 0, buffer, &size, size_p);
}
static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
@@ -439,81 +451,13 @@
return it;
free_return:
- cache_tree_free(it);
+ cache_tree_free(&it);
return NULL;
}
-static struct cache_tree *cache_tree_read(unsigned char *sha1,
- const char *buffer,
- unsigned long size)
+struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
{
- /* check the cache-tree matches the index */
- if (memcmp(buffer, sha1, 20))
- return NULL; /* checksum mismatch */
- if (buffer[20])
+ if (buffer[0])
return NULL; /* not the whole tree */
- buffer += 20;
- size -= 20;
return read_one(&buffer, &size);
}
-
-struct cache_tree *read_cache_tree(unsigned char *sha1)
-{
- int fd;
- struct stat st;
- char path[PATH_MAX];
- unsigned long size = 0;
- void *map;
- struct cache_tree *it;
-
- sprintf(path, "%s.aux", get_index_file());
- fd = open(path, O_RDONLY);
- if (fd < 0)
- return cache_tree();
-
- if (fstat(fd, &st))
- return cache_tree();
- size = st.st_size;
- map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
- close(fd);
- if (map == MAP_FAILED)
- return cache_tree();
- it = cache_tree_read(sha1, map, size);
- munmap(map, size);
- if (!it)
- return cache_tree();
- return it;
-}
-
-int write_cache_tree(const unsigned char *sha1, struct cache_tree *root)
-{
- char path[PATH_MAX];
- unsigned long size = 0;
- void *buf, *buffer;
- int fd, ret = -1;
-
- sprintf(path, "%s.aux", get_index_file());
- if (!root) {
- unlink(path);
- return -1;
- }
- fd = open(path, O_WRONLY|O_CREAT, 0666);
- if (fd < 0)
- return -1;
- buffer = buf = cache_tree_write(sha1, root, &size);
- while (size) {
- int written = xwrite(fd, buf, size);
- if (written <= 0)
- goto fail;
- buf += written;
- size -= written;
- }
- ret = 0;
-
- fail:
- close(fd);
- free(buffer);
- if (ret)
- unlink(path);
- return ret;
-}
diff --git a/cache-tree.h b/cache-tree.h
index 7b149af..c70a769 100644
--- a/cache-tree.h
+++ b/cache-tree.h
@@ -18,12 +18,13 @@
};
struct cache_tree *cache_tree(void);
-void cache_tree_free(struct cache_tree *);
+void cache_tree_free(struct cache_tree **);
void cache_tree_invalidate_path(struct cache_tree *, const char *);
-int write_cache_tree(const unsigned char *, struct cache_tree *);
-struct cache_tree *read_cache_tree(unsigned char *);
-int cache_tree_update(struct cache_tree *, struct cache_entry **, int, int);
+void *cache_tree_write(struct cache_tree *root, unsigned long *size_p);
+struct cache_tree *cache_tree_read(const char *buffer, unsigned long size);
+int cache_tree_fully_valid(struct cache_tree *);
+int cache_tree_update(struct cache_tree *, struct cache_entry **, int, int);
#endif
diff --git a/cache.h b/cache.h
index 8c9947e..a080727 100644
--- a/cache.h
+++ b/cache.h
@@ -114,6 +114,7 @@
extern struct cache_entry **active_cache;
extern unsigned int active_nr, active_alloc, active_cache_changed;
+extern struct cache_tree *active_cache_tree;
#define GIT_DIR_ENVIRONMENT "GIT_DIR"
#define DEFAULT_GIT_DIR_ENVIRONMENT ".git"
@@ -138,11 +139,8 @@
#define alloc_nr(x) (((x)+16)*3/2)
/* Initialize and use the cache information */
-extern int read_cache_1(unsigned char *);
-extern int write_cache_1(int, struct cache_entry **, int, unsigned char *);
extern int read_cache(void);
-extern int write_cache(int, struct cache_entry **, int);
-
+extern int write_cache(int newfd, struct cache_entry **cache, int entries);
extern int cache_name_pos(const char *name, int namelen);
#define ADD_CACHE_OK_TO_ADD 1 /* Ok to add */
#define ADD_CACHE_OK_TO_REPLACE 2 /* Ok to replace file/directory */
diff --git a/checkout-index.c b/checkout-index.c
index dd6a2d8..e56c354 100644
--- a/checkout-index.c
+++ b/checkout-index.c
@@ -39,6 +39,7 @@
#include "cache.h"
#include "strbuf.h"
#include "quote.h"
+#include "cache-tree.h"
#define CHECKOUT_ALL 4
static const char *prefix;
diff --git a/dump-cache-tree.c b/dump-cache-tree.c
index 80f8683..01e8bff 100644
--- a/dump-cache-tree.c
+++ b/dump-cache-tree.c
@@ -2,12 +2,11 @@
#include "tree.h"
#include "cache-tree.h"
-static unsigned char active_cache_sha1[20];
-static struct cache_tree *active_cache_tree;
-
static void dump_cache_tree(struct cache_tree *it, const char *pfx)
{
int i;
+ if (!it)
+ return;
if (it->entry_count < 0)
printf("%-40s %s\n", "invalid", pfx);
else
@@ -24,9 +23,8 @@
int main(int ac, char **av)
{
- if (read_cache_1(active_cache_sha1) < 0)
+ if (read_cache() < 0)
die("unable to read index file");
- active_cache_tree = read_cache_tree(active_cache_sha1);
dump_cache_tree(active_cache_tree, "");
return 0;
}
diff --git a/read-cache.c b/read-cache.c
index 50e094e..1f71d12 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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
}
/* 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 @@
}
}
-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 @@
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);
}
diff --git a/read-tree.c b/read-tree.c
index 26f4f7e..1c65101 100644
--- a/read-tree.c
+++ b/read-tree.c
@@ -9,6 +9,7 @@
#include "object.h"
#include "tree.h"
+#include "cache-tree.h"
#include <sys/time.h>
#include <signal.h>
@@ -828,6 +829,7 @@
}
unpack_trees(fn);
+ cache_tree_free(&active_cache_tree);
if (write_cache(newfd, active_cache, active_nr) ||
commit_index_file(&cache_file))
die("unable to write new index file");
diff --git a/update-index.c b/update-index.c
index 86f5394..d6d3295 100644
--- a/update-index.c
+++ b/update-index.c
@@ -6,12 +6,8 @@
#include "cache.h"
#include "strbuf.h"
#include "quote.h"
-#include "tree.h"
#include "cache-tree.h"
-static unsigned char active_cache_sha1[20];
-static struct cache_tree *active_cache_tree;
-
/*
* Default to not allowing changes to the list of files. The
* tool doesn't actually care, but this makes it harder to add
@@ -501,10 +497,9 @@
if (newfd < 0)
die("unable to create new cachefile");
- entries = read_cache_1(active_cache_sha1);
+ entries = read_cache();
if (entries < 0)
die("cache corrupted");
- active_cache_tree = read_cache_tree(active_cache_sha1);
for (i = 1 ; i < argc; i++) {
const char *path = argv[i];
@@ -630,11 +625,9 @@
}
}
if (active_cache_changed) {
- if (write_cache_1(newfd, active_cache, active_nr,
- active_cache_sha1) ||
+ if (write_cache(newfd, active_cache, active_nr) ||
commit_index_file(&cache_file))
die("Unable to write new cachefile");
- write_cache_tree(active_cache_sha1, active_cache_tree);
}
return has_errors ? 1 : 0;
diff --git a/write-tree.c b/write-tree.c
index cef0c5b..a506992 100644
--- a/write-tree.c
+++ b/write-tree.c
@@ -7,21 +7,20 @@
#include "tree.h"
#include "cache-tree.h"
-static unsigned char active_cache_sha1[20];
-static struct cache_tree *active_cache_tree;
-
static int missing_ok = 0;
static const char write_tree_usage[] = "git-write-tree [--missing-ok]";
+static struct cache_file cache_file;
+
int main(int argc, char **argv)
{
- int entries;
+ int entries, was_valid, newfd;
setup_git_directory();
- entries = read_cache_1(active_cache_sha1);
- active_cache_tree = read_cache_tree(active_cache_sha1);
+ newfd = hold_index_file_for_update(&cache_file, get_index_file());
+ entries = read_cache();
if (argc == 2) {
if (!strcmp(argv[1], "--missing-ok"))
missing_ok = 1;
@@ -35,11 +34,26 @@
if (entries < 0)
die("git-write-tree: error reading cache");
- if (cache_tree_update(active_cache_tree, active_cache, active_nr,
- missing_ok))
- die("git-write-tree: error building trees");
- write_cache_tree(active_cache_sha1, active_cache_tree);
+ if (!active_cache_tree)
+ active_cache_tree = cache_tree();
+ was_valid = cache_tree_fully_valid(active_cache_tree);
+ if (!was_valid) {
+ if (cache_tree_update(active_cache_tree,
+ active_cache, active_nr,
+ missing_ok) < 0)
+ die("git-write-tree: error building trees");
+ if (0 <= newfd) {
+ if (!write_cache(newfd, active_cache, active_nr))
+ commit_index_file(&cache_file);
+ }
+ /* Not being able to write is fine -- we are only interested
+ * in updating the cache-tree part, and if the next caller
+ * ends up using the old index with unupdated cache-tree part
+ * it misses the work we did here, but that is just a
+ * performance penalty and not a big deal.
+ */
+ }
printf("%s\n", sha1_to_hex(active_cache_tree->sha1));
return 0;
}
