sha1_file.c: expose map_sha1_file() interface.

This exposes map_sha1_file() interface to mmap a loose object file,
and legacy_loose_object() function, split from unpack_sha1_header().

They will be used in the next patch to reuse the deflated data from
new-style loose object files when generating packs.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/cache.h b/cache.h
index eee5fc9f8d75af20a1d03d569c702980f6c04469..01835ef432acdb4db94345e0058c1baafabd2b88 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -240,6 +240,8 @@ extern int move_temp_to_file(const char *tmpfile, char *filename);
 
 extern int has_sha1_pack(const unsigned char *sha1);
 extern int has_sha1_file(const unsigned char *sha1);
+extern void *map_sha1_file(const unsigned char *sha1, unsigned long *);
+extern int legacy_loose_object(unsigned char *);
 
 extern int has_pack_file(const unsigned char *sha1);
 extern int has_pack_index(const unsigned char *sha1);

diff --git a/sha1_file.c b/sha1_file.c
index 43bc2ea0cf039bb9fd02c8313981e85bd7398d33..51e07d5a45b6740c53bfc7d4b6b11d3f66e07f6e 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -646,8 +646,7 @@ int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long siz
        return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 }
 
-static void *map_sha1_file_internal(const unsigned char *sha1,
-                                   unsigned long *size)
+void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 {
        struct stat st;
        void *map;
@@ -684,10 +683,26 @@ static void *map_sha1_file_internal(const unsigned char *sha1,
        return map;
 }
 
+int legacy_loose_object(unsigned char *map)
+{
+       unsigned int word;
+
+       /*
+        * Is it a zlib-compressed buffer? If so, the first byte
+        * must be 0x78 (15-bit window size, deflated), and the
+        * first 16-bit word is evenly divisible by 31
+        */
+       word = (map[0] << 8) + map[1];
+       if (map[0] == 0x78 && !(word % 31))
+               return 1;
+       else
+               return 0;
+}
+
 static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
 {
        unsigned char c;
-       unsigned int word, bits;
+       unsigned int bits;
        unsigned long size;
        static const char *typename[8] = {
                NULL,   /* OBJ_EXT */
@@ -703,13 +718,7 @@ static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned lon
        stream->next_out = buffer;
        stream->avail_out = bufsiz;
 
-       /*
-        * Is it a zlib-compressed buffer? If so, the first byte
-        * must be 0x78 (15-bit window size, deflated), and the
-        * first 16-bit word is evenly divisible by 31
-        */
-       word = (map[0] << 8) + map[1];
-       if (map[0] == 0x78 && !(word % 31)) {
+       if (legacy_loose_object(map)) {
                inflateInit(stream);
                return inflate(stream, 0);
        }
@@ -1246,7 +1255,7 @@ int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep
        z_stream stream;
        char hdr[128];
 
-       map = map_sha1_file_internal(sha1, &mapsize);
+       map = map_sha1_file(sha1, &mapsize);
        if (!map) {
                struct pack_entry e;
 
@@ -1291,7 +1300,7 @@ void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size
 
        if (find_pack_entry(sha1, &e))
                return read_packed_sha1(sha1, type, size);
-       map = map_sha1_file_internal(sha1, &mapsize);
+       map = map_sha1_file(sha1, &mapsize);
        if (map) {
                buf = unpack_sha1_file(map, mapsize, type, size);
                munmap(map, mapsize);
@@ -1629,7 +1638,7 @@ int write_sha1_to_fd(int fd, const unsigned char *sha1)
 {
        int retval;
        unsigned long objsize;
-       void *buf = map_sha1_file_internal(sha1, &objsize);
+       void *buf = map_sha1_file(sha1, &objsize);
 
        if (buf) {
                retval = write_buffer(fd, buf, objsize);