#include "cache.h"
#include "object.h"
#include "delta.h"
+#include "pack.h"
#include "csum-file.h"
static const char pack_usage[] = "git-pack-objects [--window=N] [--depth=N] {--stdout | base-name} < object-list";
-/*
- * The object type is a single-character shorthand:
- * - 'C' for "Commit"
- * - 'T' for "Tree"
- * - 'B' for "Blob"
- * - 'G' for "taG"
- * - 'D' for "Delta"
- */
struct object_entry {
unsigned char sha1[20];
unsigned long size;
unsigned long offset;
unsigned int depth;
unsigned int hash;
- unsigned char type;
+ enum object_type type;
unsigned long delta_size;
struct object_entry *delta;
};
if (!otherbuf)
die("unable to read %s", sha1_to_hex(entry->delta->sha1));
delta_buf = diff_delta(otherbuf, othersize,
- buf, size, &delta_size, ~0UL);
+ buf, size, &delta_size, 0);
if (!delta_buf || delta_size != entry->delta_size)
die("delta size changed");
free(buf);
return delta_buf;
}
+/*
+ * The per-object header is a pretty dense thing, which is
+ * - first byte: low four bits are "size", then three bits of "type",
+ * and the high bit is "size continues".
+ * - each byte afterwards: low seven bits are size continuation,
+ * with the high bit being "size continues"
+ */
+static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
+{
+ int n = 1;
+ unsigned char c;
+
+ if (type < OBJ_COMMIT || type > OBJ_DELTA)
+ die("bad type %d", type);
+
+ c = (type << 4) | (size & 15);
+ size >>= 4;
+ while (size) {
+ *hdr++ = c | 0x80;
+ c = size & 0x7f;
+ size >>= 7;
+ n++;
+ }
+ *hdr = c;
+ return n;
+}
+
static unsigned long write_object(struct sha1file *f, struct object_entry *entry)
{
unsigned long size;
char type[10];
void *buf = read_sha1_file(entry->sha1, type, &size);
- char header[25];
+ unsigned char header[10];
unsigned hdrlen, datalen;
+ enum object_type obj_type;
if (!buf)
die("unable to read %s", sha1_to_hex(entry->sha1));
die("object %s size inconsistency (%lu vs %lu)", sha1_to_hex(entry->sha1), size, entry->size);
/*
- * The object header is a byte of 'type' followed by four bytes of
- * length, except for deltas that has the 20 bytes of delta sha
- * instead.
+ * The object header is a byte of 'type' followed by zero or
+ * more bytes of length. For deltas, the 20 bytes of delta sha1
+ * follows that.
*/
- header[0] = entry->type;
- hdrlen = 5;
+ obj_type = entry->type;
if (entry->delta) {
- header[0] = 'D';
- memcpy(header+5, entry->delta, 20);
buf = delta_against(buf, size, entry);
size = entry->delta_size;
- hdrlen = 25;
+ obj_type = OBJ_DELTA;
}
- datalen = htonl(size);
- memcpy(header+1, &datalen, 4);
+ hdrlen = encode_header(obj_type, size, header);
sha1write(f, header, hdrlen);
+ if (entry->delta) {
+ sha1write(f, entry->delta, 20);
+ hdrlen += 20;
+ }
datalen = sha1write_compressed(f, buf, size);
free(buf);
return hdrlen + datalen;
}
+static unsigned long write_one(struct sha1file *f,
+ struct object_entry *e,
+ unsigned long offset)
+{
+ if (e->offset)
+ /* offset starts from header size and cannot be zero
+ * if it is written already.
+ */
+ return offset;
+ e->offset = offset;
+ offset += write_object(f, e);
+ /* if we are delitified, write out its base object. */
+ if (e->delta)
+ offset = write_one(f, e->delta, offset);
+ return offset;
+}
+
static void write_pack_file(void)
{
int i;
struct sha1file *f;
- unsigned long offset = 0;
+ unsigned long offset;
unsigned long mb;
+ struct pack_header hdr;
if (!base_name)
f = sha1fd(1, "<stdout>");
else
f = sha1create("%s.%s", base_name, "pack");
- for (i = 0; i < nr_objects; i++) {
- struct object_entry *entry = objects + i;
- entry->offset = offset;
- offset += write_object(f, entry);
- }
+ hdr.hdr_signature = htonl(PACK_SIGNATURE);
+ hdr.hdr_version = htonl(PACK_VERSION);
+ hdr.hdr_entries = htonl(nr_objects);
+ sha1write(f, &hdr, sizeof(hdr));
+ offset = sizeof(hdr);
+ for (i = 0; i < nr_objects; i++)
+ offset = write_one(f, objects + i, offset);
+
sha1close(f, pack_file_sha1, 1);
mb = offset >> 20;
offset &= 0xfffff;
if (!sha1_object_info(entry->sha1, type, &entry->size)) {
if (!strcmp(type, "commit")) {
- entry->type = 'C';
+ entry->type = OBJ_COMMIT;
} else if (!strcmp(type, "tree")) {
- entry->type = 'T';
+ entry->type = OBJ_TREE;
} else if (!strcmp(type, "blob")) {
- entry->type = 'B';
+ entry->type = OBJ_BLOB;
} else if (!strcmp(type, "tag")) {
- entry->type = 'G';
+ entry->type = OBJ_TAG;
} else
die("unable to pack object %s of type %s",
sha1_to_hex(entry->sha1), type);
projects / git.git / blobdiff