* 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;
+
+int cache_errno = 0;
+
+static void *cache_mmap = NULL;
+static size_t cache_mmap_size = 0;
+
/*
* This only updates the "non-critical" parts of the directory
* cache, ie the parts that aren't tracked by GIT, and only used
return 0;
}
-/* Three functions to allow overloaded pointer return; see linux/err.h */
-static inline void *ERR_PTR(long error)
-{
- return (void *) error;
-}
-
-static inline long PTR_ERR(const void *ptr)
-{
- return (long) ptr;
-}
-
-static inline long IS_ERR(const void *ptr)
-{
- return (unsigned long)ptr > (unsigned long)-1000L;
-}
-
/*
* "refresh" does not calculate a new sha1 file or bring the
* cache up-to-date for mode/content changes. But what it
* For example, you'd want to do this after doing a "git-read-tree",
* to link up the stat cache details with the proper files.
*/
-static struct cache_entry *refresh_entry(struct cache_entry *ce, int really)
+struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really)
{
struct stat st;
struct cache_entry *updated;
int changed, size;
- if (lstat(ce->name, &st) < 0)
- return ERR_PTR(-errno);
+ if (lstat(ce->name, &st) < 0) {
+ cache_errno = errno;
+ return NULL;
+ }
changed = ce_match_stat(ce, &st, really);
if (!changed) {
!(ce->ce_flags & htons(CE_VALID)))
; /* mark this one VALID again */
else
- return NULL;
+ return ce;
}
- if (ce_modified(ce, &st, really))
- return ERR_PTR(-EINVAL);
+ if (ce_modified(ce, &st, really)) {
+ cache_errno = EINVAL;
+ return NULL;
+ }
size = ce_size(ce);
updated = xmalloc(size);
continue;
}
- new = refresh_entry(ce, really);
- if (!new)
+ new = refresh_cache_entry(ce, really);
+ if (new == ce)
continue;
- if (IS_ERR(new)) {
- if (not_new && PTR_ERR(new) == -ENOENT)
+ if (!new) {
+ if (not_new && cache_errno == ENOENT)
continue;
- if (really && PTR_ERR(new) == -EINVAL) {
+ if (really && cache_errno == EINVAL) {
/* If we are doing --really-refresh that
* means the index is not valid anymore.
*/
SHA1_Init(&c);
SHA1_Update(&c, hdr, size - 20);
SHA1_Final(sha1, &c);
- if (memcmp(sha1, (void *)hdr + size - 20, 20))
+ if (memcmp(sha1, (char *) hdr + size - 20, 20))
return error("bad index file sha1 signature");
return 0;
}
+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)
+{
+ return read_cache_from(get_index_file());
+}
+
+/* remember to discard_cache() before reading a different cache! */
+int read_cache_from(const char *path)
{
int fd, i;
struct stat st;
- unsigned long size, offset;
- void *map;
+ unsigned long offset;
struct cache_header *hdr;
errno = EBUSY;
- if (active_cache)
+ if (cache_mmap)
return active_nr;
errno = ENOENT;
index_file_timestamp = 0;
- fd = open(get_index_file(), O_RDONLY);
+ fd = open(path, O_RDONLY);
if (fd < 0) {
if (errno == ENOENT)
return 0;
die("index file open failed (%s)", strerror(errno));
}
- size = 0; // avoid gcc warning
- map = MAP_FAILED;
+ cache_mmap = MAP_FAILED;
if (!fstat(fd, &st)) {
- size = st.st_size;
+ cache_mmap_size = st.st_size;
errno = EINVAL;
- if (size >= sizeof(struct cache_header) + 20)
- map = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
+ if (cache_mmap_size >= sizeof(struct cache_header) + 20)
+ cache_mmap = mmap(NULL, cache_mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
}
close(fd);
- if (map == MAP_FAILED)
+ if (cache_mmap == MAP_FAILED)
die("index file mmap failed (%s)", strerror(errno));
- hdr = map;
- if (verify_hdr(hdr, size) < 0)
+ hdr = cache_mmap;
+ if (verify_hdr(hdr, cache_mmap_size) < 0)
goto unmap;
active_nr = ntohl(hdr->hdr_entries);
offset = sizeof(*hdr);
for (i = 0; i < active_nr; i++) {
- struct cache_entry *ce = map + offset;
+ struct cache_entry *ce = (struct cache_entry *) ((char *) cache_mmap + offset);
offset = offset + ce_size(ce);
active_cache[i] = ce;
}
index_file_timestamp = st.st_mtime;
+ while (offset <= cache_mmap_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, (char *) cache_mmap + offset + 4, 4);
+ extsize = ntohl(extsize);
+ if (read_index_extension(((const char *) cache_mmap) + offset,
+ (char *) cache_mmap + offset + 8,
+ extsize) < 0)
+ goto unmap;
+ offset += 8;
+ offset += extsize;
+ }
return active_nr;
unmap:
- munmap(map, size);
+ munmap(cache_mmap, cache_mmap_size);
errno = EINVAL;
die("index file corrupt");
}
+int discard_cache()
+{
+ int ret;
+
+ if (cache_mmap == NULL)
+ return 0;
+ ret = munmap(cache_mmap, cache_mmap_size);
+ cache_mmap = NULL;
+ cache_mmap_size = 0;
+ active_nr = active_cache_changed = 0;
+ index_file_timestamp = 0;
+ cache_tree_free(&active_cache_tree);
+
+ /* no need to throw away allocated active_cache */
+ return ret;
+}
+
#define WRITE_BUFFER_SIZE 8192
static unsigned char write_buffer[WRITE_BUFFER_SIZE];
static unsigned long write_buffer_len;
}
write_buffer_len = buffered;
len -= partial;
- data += partial;
+ data = (char *) data + partial;
}
return 0;
}
+static int write_index_ext_header(SHA_CTX *context, int fd,
+ unsigned int ext, unsigned int 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;
if (ce_write(&c, newfd, ce, ce_size(ce)) < 0)
return -1;
}
+
+ /* 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);
}