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-rw-r--r--unpack-objects.c418
1 files changed, 190 insertions, 228 deletions
diff --git a/unpack-objects.c b/unpack-objects.c
index fbc8994..0892d2b 100644
--- a/unpack-objects.c
+++ b/unpack-objects.c
@@ -4,278 +4,213 @@
#include "pack.h"
static int dry_run;
-static int nr_entries;
-static const char *base_name;
-static const char unpack_usage[] = "git-unpack-objects basename";
+static const char unpack_usage[] = "git-unpack-objects < pack-file";
-struct pack_entry {
- unsigned int offset; /* network byte order */
- unsigned char sha1[20];
-};
+/* We always read in 4kB chunks. */
+static unsigned char buffer[4096];
+static unsigned long offset, len, eof;
+static SHA_CTX ctx;
-static void *pack_base;
-static unsigned long pack_size;
-static void *index_base;
-static unsigned long index_size;
+/*
+ * Make sure at least "min" bytes are available in the buffer, and
+ * return the pointer to the buffer.
+ */
+static void * fill(int min)
+{
+ if (min <= len)
+ return buffer + offset;
+ if (eof)
+ die("unable to fill input");
+ if (min > sizeof(buffer))
+ die("cannot fill %d bytes", min);
+ if (offset) {
+ SHA1_Update(&ctx, buffer, offset);
+ memcpy(buffer, buffer + offset, len);
+ offset = 0;
+ }
+ do {
+ int ret = read(0, buffer + len, sizeof(buffer) - len);
+ if (ret <= 0) {
+ if (!ret)
+ die("early EOF");
+ if (errno == EAGAIN || errno == EINTR)
+ continue;
+ die("read error on input: %s", strerror(errno));
+ }
+ len += ret;
+ } while (len < min);
+ return buffer;
+}
-static struct pack_entry **pack_list;
+static void use(int bytes)
+{
+ if (bytes > len)
+ die("used more bytes than were available");
+ len -= bytes;
+ offset += bytes;
+}
-static void *map_file(const char *suffix, unsigned long *sizep)
+static void *get_data(unsigned long size)
{
- static char pathname[PATH_MAX];
- unsigned long len;
- int fd;
- struct stat st;
- void *map;
-
- len = snprintf(pathname, PATH_MAX, "%s.%s", base_name, suffix);
- if (len >= PATH_MAX)
- die("bad pack base-name");
- fd = open(pathname, O_RDONLY);
- if (fd < 0 || fstat(fd, &st))
- die("unable to open '%s'", pathname);
- len = st.st_size;
- if (!len)
- die("bad pack file '%s'", pathname);
- map = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 0);
- if (-1 == (int)(long)map)
- die("unable to mmap '%s'", pathname);
- close(fd);
- *sizep = len;
- return map;
+ z_stream stream;
+ void *buf = xmalloc(size);
+
+ if (!size)
+ return buf;
+ memset(&stream, 0, sizeof(stream));
+
+ stream.next_out = buf;
+ stream.avail_out = size;
+ stream.next_in = fill(1);
+ stream.avail_in = len;
+ inflateInit(&stream);
+
+ for (;;) {
+ int ret = inflate(&stream, 0);
+ use(len - stream.avail_in);
+ if (stream.total_out == size && ret == Z_STREAM_END)
+ break;
+ if (ret != Z_OK)
+ die("inflate returned %d\n", ret);
+ stream.next_in = fill(1);
+ stream.avail_in = len;
+ }
+ return buf;
}
-static int sort_by_offset(const void *_a, const void *_b)
+struct delta_info {
+ unsigned char base_sha1[20];
+ unsigned long size;
+ void *delta;
+ struct delta_info *next;
+};
+
+static struct delta_info *delta_list;
+
+static void add_delta_to_list(unsigned char *base_sha1, void *delta, unsigned long size)
{
- struct pack_entry *a = *(struct pack_entry **)_a;
- struct pack_entry *b = *(struct pack_entry **)_b;
- unsigned int o1, o2;
+ struct delta_info *info = xmalloc(sizeof(*info));
- o1 = ntohl(a->offset);
- o2 = ntohl(b->offset);
- return o1 < o2 ? -1 : 1;
+ memcpy(info->base_sha1, base_sha1, 20);
+ info->size = size;
+ info->delta = delta;
+ info->next = delta_list;
+ delta_list = info;
}
-static int check_index(void)
+static void added_object(unsigned char *sha1, char *type, void *data, unsigned long size);
+
+static int resolve_delta(char *type,
+ void *base, unsigned long base_size,
+ void *delta, unsigned long delta_size)
{
- unsigned int *array = index_base;
- unsigned int nr;
- int i;
+ void *result;
+ unsigned long result_size;
+ unsigned char sha1[20];
- if (index_size < 4*256 + 20)
- return error("index file too small");
- nr = 0;
- for (i = 0; i < 256; i++) {
- unsigned int n = ntohl(array[i]);
- if (n < nr)
- return error("non-monotonic index");
- nr = n;
- }
- /*
- * Total size:
- * - 256 index entries 4 bytes each
- * - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
- * - 20-byte SHA1 of the packfile
- * - 20-byte SHA1 file checksum
- */
- if (index_size != 4*256 + nr * 24 + 20 + 20)
- return error("wrong index file size");
-
- nr_entries = nr;
- pack_list = xmalloc(nr * sizeof(struct pack_entry *));
- for (i = 0; i < nr; i++)
- pack_list[i] = index_base + 4*256 + i*24;
-
- qsort(pack_list, nr, sizeof(*pack_list), sort_by_offset);
-
- printf("%d entries\n", nr);
+ result = patch_delta(base, base_size,
+ delta, delta_size,
+ &result_size);
+ if (!result)
+ die("failed to apply delta");
+ free(delta);
+
+ if (write_sha1_file(result, result_size, type, sha1) < 0)
+ die("failed to write object");
+ added_object(sha1, type, result, result_size);
+ free(result);
return 0;
}
-static int unpack_non_delta_entry(struct pack_entry *entry,
- enum object_type kind,
- unsigned char *data,
- unsigned long size,
- unsigned long left)
+static void added_object(unsigned char *sha1, char *type, void *data, unsigned long size)
{
- int st;
- z_stream stream;
- char *buffer;
+ struct delta_info **p = &delta_list;
+ struct delta_info *info;
+
+ while ((info = *p) != NULL) {
+ if (!memcmp(info->base_sha1, sha1, 20)) {
+ *p = info->next;
+ p = &delta_list;
+ resolve_delta(type, data, size, info->delta, info->size);
+ free(info);
+ continue;
+ }
+ p = &info->next;
+ }
+}
+
+static int unpack_non_delta_entry(enum object_type kind, unsigned long size)
+{
+ void *buf = get_data(size);
unsigned char sha1[20];
char *type;
- printf("%s %c %lu\n", sha1_to_hex(entry->sha1), ".CTBGD"[kind], size);
- if (dry_run)
- return 0;
-
- buffer = xmalloc(size + 1);
- buffer[size] = 0;
- memset(&stream, 0, sizeof(stream));
- stream.next_in = data;
- stream.avail_in = left;
- stream.next_out = buffer;
- stream.avail_out = size;
-
- inflateInit(&stream);
- st = inflate(&stream, Z_FINISH);
- inflateEnd(&stream);
- if ((st != Z_STREAM_END) || stream.total_out != size)
- goto err_finish;
switch (kind) {
case OBJ_COMMIT: type = "commit"; break;
case OBJ_TREE: type = "tree"; break;
case OBJ_BLOB: type = "blob"; break;
case OBJ_TAG: type = "tag"; break;
- default: goto err_finish;
+ default: die("bad type %d", kind);
}
- if (write_sha1_file(buffer, size, type, sha1) < 0)
- die("failed to write %s (%s)",
- sha1_to_hex(entry->sha1), type);
- printf("%s %s\n", sha1_to_hex(sha1), type);
- if (memcmp(sha1, entry->sha1, 20))
- die("resulting %s have wrong SHA1", type);
-
- finish:
- st = 0;
- free(buffer);
- return st;
- err_finish:
- st = -1;
- goto finish;
-}
-
-static int find_pack_entry(unsigned char *sha1, struct pack_entry **ent)
-{
- int *level1_ofs = index_base;
- int hi = ntohl(level1_ofs[*sha1]);
- int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
- void *index = index_base + 4*256;
-
- do {
- int mi = (lo + hi) / 2;
- int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
- if (!cmp) {
- *ent = index + 24 * mi;
- return 1;
- }
- if (cmp > 0)
- hi = mi;
- else
- lo = mi+1;
- } while (lo < hi);
+ if (write_sha1_file(buf, size, type, sha1) < 0)
+ die("failed to write object");
+ added_object(sha1, type, buf, size);
+ free(buf);
return 0;
}
-/* forward declaration for a mutually recursive function */
-static void unpack_entry(struct pack_entry *);
-
-static int unpack_delta_entry(struct pack_entry *entry,
- unsigned char *base_sha1,
- unsigned long delta_size,
- unsigned long left)
+static int unpack_delta_entry(unsigned long delta_size)
{
- void *data, *delta_data, *result, *base;
- unsigned long data_size, result_size, base_size;
- z_stream stream;
- int st;
+ void *delta_data, *base;
+ unsigned long base_size;
char type[20];
- unsigned char sha1[20];
+ unsigned char base_sha1[20];
- if (left < 20)
- die("truncated pack file");
- data = base_sha1 + 20;
- data_size = left - 20;
- printf("%s D %lu", sha1_to_hex(entry->sha1), delta_size);
- printf(" %s\n", sha1_to_hex(base_sha1));
+ memcpy(base_sha1, fill(20), 20);
+ use(20);
- if (dry_run)
- return 0;
+ delta_data = get_data(delta_size);
- /* pack+5 is the base sha1, unless we have it, we need to
- * unpack it first.
- */
if (!has_sha1_file(base_sha1)) {
- struct pack_entry *base;
- if (!find_pack_entry(base_sha1, &base))
- die("cannot find delta-pack base object");
- unpack_entry(base);
+ add_delta_to_list(base_sha1, delta_data, delta_size);
+ return 0;
}
- delta_data = xmalloc(delta_size);
-
- memset(&stream, 0, sizeof(stream));
-
- stream.next_in = data;
- stream.avail_in = data_size;
- stream.next_out = delta_data;
- stream.avail_out = delta_size;
-
- inflateInit(&stream);
- st = inflate(&stream, Z_FINISH);
- inflateEnd(&stream);
- if ((st != Z_STREAM_END) || stream.total_out != delta_size)
- die("delta data unpack failed");
-
base = read_sha1_file(base_sha1, type, &base_size);
if (!base)
die("failed to read delta-pack base object %s", sha1_to_hex(base_sha1));
- result = patch_delta(base, base_size,
- delta_data, delta_size,
- &result_size);
- if (!result)
- die("failed to apply delta");
- free(delta_data);
-
- if (write_sha1_file(result, result_size, type, sha1) < 0)
- die("failed to write %s (%s)",
- sha1_to_hex(entry->sha1), type);
- free(result);
- printf("%s %s\n", sha1_to_hex(sha1), type);
- if (memcmp(sha1, entry->sha1, 20))
- die("resulting %s have wrong SHA1", type);
- return 0;
+ return resolve_delta(type, base, base_size, delta_data, delta_size);
}
-static void unpack_entry(struct pack_entry *entry)
+static void unpack_one(void)
{
- unsigned long offset, size, left;
unsigned char *pack, c;
- int type;
+ unsigned long size;
+ enum object_type type;
- /* Have we done this one already due to deltas based on it? */
- if (lookup_object(entry->sha1))
- return;
-
- offset = ntohl(entry->offset);
- if (offset >= pack_size)
- goto bad;
-
- pack = pack_base + offset;
- c = *pack++;
- offset++;
+ pack = fill(1);
+ c = *pack;
+ use(1);
type = (c >> 4) & 7;
size = (c & 15);
while (c & 0x80) {
- if (offset >= pack_size)
- goto bad;
- offset++;
+ pack = fill(1);
c = *pack++;
+ use(1);
size = (size << 7) + (c & 0x7f);
-
}
- left = pack_size - offset;
switch (type) {
case OBJ_COMMIT:
case OBJ_TREE:
case OBJ_BLOB:
case OBJ_TAG:
- unpack_non_delta_entry(entry, type, pack, size, left);
+ unpack_non_delta_entry(type, size);
return;
case OBJ_DELTA:
- unpack_delta_entry(entry, pack, size, left);
+ unpack_delta_entry(size);
return;
+ default:
+ die("bad object type %d", type);
}
-bad:
- die("corrupted pack file");
}
/*
@@ -285,17 +220,28 @@ bad:
*/
static void unpack_all(void)
{
- int i = nr_entries;
-
- while (--i >= 0) {
- struct pack_entry *entry = pack_list[i];
- unpack_entry(entry);
- }
+ int i;
+ struct pack_header *hdr = fill(sizeof(struct pack_header));
+ unsigned version = ntohl(hdr->hdr_version);
+ unsigned nr_objects = ntohl(hdr->hdr_entries);
+
+ if (ntohl(hdr->hdr_signature) != PACK_SIGNATURE)
+ die("bad pack file");
+ if (version != 1)
+ die("unable to handle pack file version %d", version);
+ fprintf(stderr, "Unpacking %d objects\n", nr_objects);
+
+ use(sizeof(struct pack_header));
+ for (i = 0; i < nr_objects; i++)
+ unpack_one();
+ if (delta_list)
+ die("unresolved deltas left after unpacking");
}
int main(int argc, char **argv)
{
int i;
+ unsigned char sha1[20];
for (i = 1 ; i < argc; i++) {
const char *arg = argv[i];
@@ -307,16 +253,32 @@ int main(int argc, char **argv)
}
usage(unpack_usage);
}
- if (base_name)
- usage(unpack_usage);
- base_name = arg;
- }
- if (!base_name)
+
+ /* We don't take any non-flag arguments now.. Maybe some day */
usage(unpack_usage);
- index_base = map_file("idx", &index_size);
- pack_base = map_file("pack", &pack_size);
- if (check_index() < 0)
- die("bad index file");
+ }
+ SHA1_Init(&ctx);
unpack_all();
+ SHA1_Update(&ctx, buffer, offset);
+ SHA1_Final(sha1, &ctx);
+ if (memcmp(fill(20), sha1, 20))
+ die("final sha1 did not match");
+ use(20);
+
+ /* Write the last part of the buffer to stdout */
+ while (len) {
+ int ret = write(1, buffer + offset, len);
+ if (!ret)
+ break;
+ if (ret < 0) {
+ if (errno == EAGAIN || errno == EINTR)
+ continue;
+ break;
+ }
+ len -= ret;
+ offset += ret;
+ }
+
+ /* All done */
return 0;
}