[PATCH 1/3] Add read_cache_from() and discard_cache()
These functions will be useful for the inbuilt merge-recursive.
Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
---
cache.h | 2 ++
read-cache.c | 57 +++++++++++++++++++++++++++++++++++++++------------------
2 files changed, 41 insertions(+), 18 deletions(-)
diff --git a/cache.h b/cache.h
index 8719939..a5343db 100644
--- a/cache.h
+++ b/cache.h
@@ -142,7 +142,9 @@ #define alloc_nr(x) (((x)+16)*3/2)
/* Initialize and use the cache information */
extern int read_cache(void);
+extern int read_cache_from(const char *path);
extern int write_cache(int newfd, struct cache_entry **cache, int entries);
+extern int discard_cache(void);
extern int verify_path(const char *path);
extern int cache_name_pos(const char *name, int namelen);
#define ADD_CACHE_OK_TO_ADD 1 /* Ok to add */
diff --git a/read-cache.c b/read-cache.c
index 3c32aae..04d2ec7 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -24,6 +24,9 @@ unsigned int active_nr = 0, active_alloc
struct cache_tree *active_cache_tree = NULL;
+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
@@ -729,39 +732,43 @@ static int read_index_extension(const ch
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);
@@ -770,12 +777,12 @@ int read_cache(void)
offset = sizeof(*hdr);
for (i = 0; i < active_nr; i++) {
- struct cache_entry *ce = (struct cache_entry *) ((char *) 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 <= size - 20 - 8) {
+ 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
@@ -783,10 +790,10 @@ int read_cache(void)
* in 4-byte network byte order.
*/
unsigned long extsize;
- memcpy(&extsize, (char *) map + offset + 4, 4);
+ memcpy(&extsize, (char *) cache_mmap + offset + 4, 4);
extsize = ntohl(extsize);
- if (read_index_extension(((const char *) map) + offset,
- (char *) map + offset + 8,
+ if (read_index_extension(((const char *) cache_mmap) + offset,
+ (char *) cache_mmap + offset + 8,
extsize) < 0)
goto unmap;
offset += 8;
@@ -795,11 +802,25 @@ int read_cache(void)
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;
+ /* 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;
--
1.4.1.rc1.gb2d14
Johannes Schindelin <johannes.schindelin@gmx.de>