#include "cache.h"
#include "object.h"
#include "delta.h"
+#include "pack.h"
+#include "csum-file.h"
+#include "diff.h"
+#include <sys/time.h>
-static const char pack_usage[] = "git-pack-objects [--window=N] [--depth=N] base-name < object-list";
-
-enum object_type {
- OBJ_NONE,
- OBJ_COMMIT,
- OBJ_TREE,
- OBJ_BLOB,
- OBJ_DELTA // NOTE! This is _not_ the same as a "delta" object in the filesystem
-};
+static const char pack_usage[] = "git-pack-objects [-q] [--no-reuse-delta] [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list";
struct object_entry {
unsigned char sha1[20];
- unsigned long size;
- unsigned long offset;
- unsigned int depth;
- unsigned int flags;
+ unsigned long size; /* uncompressed size */
+ unsigned long offset; /* offset into the final pack file;
+ * nonzero if already written.
+ */
+ unsigned int depth; /* delta depth */
+ unsigned int delta_limit; /* base adjustment for in-pack delta */
+ unsigned int hash; /* name hint hash */
enum object_type type;
- unsigned long delta_size;
- struct object_entry *delta;
+ enum object_type in_pack_type; /* could be delta */
+ unsigned long delta_size; /* delta data size (uncompressed) */
+ struct object_entry *delta; /* delta base object */
+ struct packed_git *in_pack; /* already in pack */
+ unsigned int in_pack_offset;
+ struct object_entry *delta_child; /* delitified objects who bases me */
+ struct object_entry *delta_sibling; /* other deltified objects who
+ * uses the same base as me
+ */
+ int preferred_base; /* we do not pack this, but is encouraged to
+ * be used as the base objectto delta huge
+ * objects against.
+ */
+ int based_on_preferred; /* current delta candidate is a preferred
+ * one, or delta against a preferred one.
+ */
};
+/*
+ * Objects we are going to pack are colected in objects array (dynamically
+ * expanded). nr_objects & nr_alloc controls this array. They are stored
+ * in the order we see -- typically rev-list --objects order that gives us
+ * nice "minimum seek" order.
+ *
+ * sorted-by-sha ans sorted-by-type are arrays of pointers that point at
+ * elements in the objects array. The former is used to build the pack
+ * index (lists object names in the ascending order to help offset lookup),
+ * and the latter is used to group similar things together by try_delta()
+ * heuristics.
+ */
+
+static unsigned char object_list_sha1[20];
+static int non_empty = 0;
+static int no_reuse_delta = 0;
+static int local = 0;
+static int incremental = 0;
static struct object_entry **sorted_by_sha, **sorted_by_type;
static struct object_entry *objects = NULL;
-static int nr_objects = 0, nr_alloc = 0;
+static int nr_objects = 0, nr_alloc = 0, nr_result = 0;
static const char *base_name;
+static unsigned char pack_file_sha1[20];
+static int progress = 1;
-struct myfile {
- int fd;
- unsigned long chars;
- unsigned char buffer[8192];
-};
+/*
+ * The object names in objects array are hashed with this hashtable,
+ * to help looking up the entry by object name. Binary search from
+ * sorted_by_sha is also possible but this was easier to code and faster.
+ * This hashtable is built after all the objects are seen.
+ */
+static int *object_ix = NULL;
+static int object_ix_hashsz = 0;
+
+/*
+ * Pack index for existing packs give us easy access to the offsets into
+ * corresponding pack file where each object's data starts, but the entries
+ * do not store the size of the compressed representation (uncompressed
+ * size is easily available by examining the pack entry header). We build
+ * a hashtable of existing packs (pack_revindex), and keep reverse index
+ * here -- pack index file is sorted by object name mapping to offset; this
+ * pack_revindex[].revindex array is an ordered list of offsets, so if you
+ * know the offset of an object, next offset is where its packed
+ * representation ends.
+ */
+struct pack_revindex {
+ struct packed_git *p;
+ unsigned long *revindex;
+} *pack_revindex = NULL;
+static int pack_revindex_hashsz = 0;
-static FILE *create_file(const char *suffix)
+/*
+ * stats
+ */
+static int written = 0;
+static int written_delta = 0;
+static int reused = 0;
+static int reused_delta = 0;
+
+static int pack_revindex_ix(struct packed_git *p)
{
- static char filename[PATH_MAX];
- unsigned len;
+ unsigned int ui = (unsigned int) p;
+ int i;
- len = snprintf(filename, PATH_MAX, "%s.%s", base_name, suffix);
- if (len >= PATH_MAX)
- die("you wascally wabbit, you");
- return fopen(filename, "w");
+ ui = ui ^ (ui >> 16); /* defeat structure alignment */
+ i = (int)(ui % pack_revindex_hashsz);
+ while (pack_revindex[i].p) {
+ if (pack_revindex[i].p == p)
+ return i;
+ if (++i == pack_revindex_hashsz)
+ i = 0;
+ }
+ return -1 - i;
}
-static unsigned long fwrite_compressed(void *in, unsigned long size, FILE *f)
+static void prepare_pack_ix(void)
{
- z_stream stream;
- unsigned long maxsize;
- void *out;
-
- memset(&stream, 0, sizeof(stream));
- deflateInit(&stream, Z_DEFAULT_COMPRESSION);
- maxsize = deflateBound(&stream, size);
- out = xmalloc(maxsize);
-
- /* Compress it */
- stream.next_in = in;
- stream.avail_in = size;
-
- stream.next_out = out;
- stream.avail_out = maxsize;
-
- while (deflate(&stream, Z_FINISH) == Z_OK)
- /* nothing */;
- deflateEnd(&stream);
-
- size = stream.total_out;
- fwrite(out, size, 1, f);
- free(out);
- return size;
+ int num;
+ struct packed_git *p;
+ for (num = 0, p = packed_git; p; p = p->next)
+ num++;
+ if (!num)
+ return;
+ pack_revindex_hashsz = num * 11;
+ pack_revindex = xcalloc(sizeof(*pack_revindex), pack_revindex_hashsz);
+ for (p = packed_git; p; p = p->next) {
+ num = pack_revindex_ix(p);
+ num = - 1 - num;
+ pack_revindex[num].p = p;
+ }
+ /* revindex elements are lazily initialized */
+}
+
+static int cmp_offset(const void *a_, const void *b_)
+{
+ unsigned long a = *(unsigned long *) a_;
+ unsigned long b = *(unsigned long *) b_;
+ if (a < b)
+ return -1;
+ else if (a == b)
+ return 0;
+ else
+ return 1;
+}
+
+/*
+ * Ordered list of offsets of objects in the pack.
+ */
+static void prepare_pack_revindex(struct pack_revindex *rix)
+{
+ struct packed_git *p = rix->p;
+ int num_ent = num_packed_objects(p);
+ int i;
+ void *index = p->index_base + 256;
+
+ rix->revindex = xmalloc(sizeof(unsigned long) * (num_ent + 1));
+ for (i = 0; i < num_ent; i++) {
+ long hl = *((long *)(index + 24 * i));
+ rix->revindex[i] = ntohl(hl);
+ }
+ /* This knows the pack format -- the 20-byte trailer
+ * follows immediately after the last object data.
+ */
+ rix->revindex[num_ent] = p->pack_size - 20;
+ qsort(rix->revindex, num_ent, sizeof(unsigned long), cmp_offset);
+}
+
+static unsigned long find_packed_object_size(struct packed_git *p,
+ unsigned long ofs)
+{
+ int num;
+ int lo, hi;
+ struct pack_revindex *rix;
+ unsigned long *revindex;
+ num = pack_revindex_ix(p);
+ if (num < 0)
+ die("internal error: pack revindex uninitialized");
+ rix = &pack_revindex[num];
+ if (!rix->revindex)
+ prepare_pack_revindex(rix);
+ revindex = rix->revindex;
+ lo = 0;
+ hi = num_packed_objects(p) + 1;
+ do {
+ int mi = (lo + hi) / 2;
+ if (revindex[mi] == ofs) {
+ return revindex[mi+1] - ofs;
+ }
+ else if (ofs < revindex[mi])
+ hi = mi;
+ else
+ lo = mi + 1;
+ } while (lo < hi);
+ die("internal error: pack revindex corrupt");
}
static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
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;
}
-static unsigned long write_object(FILE *f, struct object_entry *entry)
+/*
+ * 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];
+ void *buf;
+ unsigned char header[10];
unsigned hdrlen, datalen;
+ enum object_type obj_type;
+ int to_reuse = 0;
- if (!buf)
- die("unable to read %s", sha1_to_hex(entry->sha1));
- if (size != entry->size)
- die("object %s size inconsistency (%lu vs %lu)", sha1_to_hex(entry->sha1), size, entry->size);
+ if (entry->preferred_base)
+ return 0;
- /*
- * 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.
- */
- header[0] = ".CTB"[entry->type];
- hdrlen = 5;
- 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 = entry->type;
+ if (! entry->in_pack)
+ to_reuse = 0; /* can't reuse what we don't have */
+ else if (obj_type == OBJ_DELTA)
+ to_reuse = 1; /* check_object() decided it for us */
+ else if (obj_type != entry->in_pack_type)
+ to_reuse = 0; /* pack has delta which is unusable */
+ else if (entry->delta)
+ to_reuse = 0; /* we want to pack afresh */
+ else
+ to_reuse = 1; /* we have it in-pack undeltified,
+ * and we do not need to deltify it.
+ */
+
+ if (! to_reuse) {
+ buf = read_sha1_file(entry->sha1, type, &size);
+ if (!buf)
+ die("unable to read %s", sha1_to_hex(entry->sha1));
+ if (size != entry->size)
+ die("object %s size inconsistency (%lu vs %lu)",
+ sha1_to_hex(entry->sha1), size, entry->size);
+ if (entry->delta) {
+ buf = delta_against(buf, size, entry);
+ size = entry->delta_size;
+ obj_type = OBJ_DELTA;
+ }
+ /*
+ * 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.
+ */
+ 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);
}
- datalen = htonl(size);
- memcpy(header+1, &datalen, 4);
- fwrite(header, hdrlen, 1, f);
- datalen = fwrite_compressed(buf, size, f);
- free(buf);
+ else {
+ struct packed_git *p = entry->in_pack;
+ use_packed_git(p);
+
+ datalen = find_packed_object_size(p, entry->in_pack_offset);
+ buf = p->pack_base + entry->in_pack_offset;
+ sha1write(f, buf, datalen);
+ unuse_packed_git(p);
+ hdrlen = 0; /* not really */
+ if (obj_type == OBJ_DELTA)
+ reused_delta++;
+ reused++;
+ }
+ if (obj_type == OBJ_DELTA)
+ written_delta++;
+ written++;
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 deltified, 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;
- FILE *f = create_file("pack");
- unsigned long offset = 0;
- unsigned long mb;
-
- for (i = 0; i < nr_objects; i++) {
- struct object_entry *entry = objects + i;
- entry->offset = offset;
- offset += write_object(f, entry);
- }
- fclose(f);
- mb = offset >> 20;
- offset &= 0xfffff;
+ struct sha1file *f;
+ unsigned long offset;
+ struct pack_header hdr;
+
+ if (!base_name)
+ f = sha1fd(1, "<stdout>");
+ else
+ f = sha1create("%s-%s.%s", base_name,
+ sha1_to_hex(object_list_sha1), "pack");
+ hdr.hdr_signature = htonl(PACK_SIGNATURE);
+ hdr.hdr_version = htonl(PACK_VERSION);
+ hdr.hdr_entries = htonl(nr_result);
+ 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);
}
static void write_index_file(void)
{
int i;
- FILE *f = create_file("idx");
+ struct sha1file *f = sha1create("%s-%s.%s", base_name,
+ sha1_to_hex(object_list_sha1), "idx");
struct object_entry **list = sorted_by_sha;
- struct object_entry **last = list + nr_objects;
+ struct object_entry **last = list + nr_result;
unsigned int array[256];
/*
* Write the first-level table (the list is sorted,
* but we use a 256-entry lookup to be able to avoid
- * having to do eight extra binary search iterations)
+ * having to do eight extra binary search iterations).
*/
for (i = 0; i < 256; i++) {
struct object_entry **next = list;
array[i] = htonl(next - sorted_by_sha);
list = next;
}
- fwrite(array, 256, sizeof(int), f);
+ sha1write(f, array, 256 * sizeof(int));
/*
* Write the actual SHA1 entries..
*/
list = sorted_by_sha;
- for (i = 0; i < nr_objects; i++) {
+ for (i = 0; i < nr_result; i++) {
struct object_entry *entry = *list++;
unsigned int offset = htonl(entry->offset);
- fwrite(&offset, 4, 1, f);
- fwrite(entry->sha1, 20, 1, f);
+ sha1write(f, &offset, 4);
+ sha1write(f, entry->sha1, 20);
}
- fclose(f);
+ sha1write(f, pack_file_sha1, 20);
+ sha1close(f, NULL, 1);
}
-static void add_object_entry(unsigned char *sha1)
+static int locate_object_entry_hash(const unsigned char *sha1)
{
+ int i;
+ unsigned int ui;
+ memcpy(&ui, sha1, sizeof(unsigned int));
+ i = ui % object_ix_hashsz;
+ while (0 < object_ix[i]) {
+ if (!memcmp(sha1, objects[object_ix[i]-1].sha1, 20))
+ return i;
+ if (++i == object_ix_hashsz)
+ i = 0;
+ }
+ return -1 - i;
+}
+
+static struct object_entry *locate_object_entry(const unsigned char *sha1)
+{
+ int i;
+
+ if (!object_ix_hashsz)
+ return NULL;
+
+ i = locate_object_entry_hash(sha1);
+ if (0 <= i)
+ return &objects[object_ix[i]-1];
+ return NULL;
+}
+
+static void rehash_objects(void)
+{
+ int i;
+ struct object_entry *oe;
+
+ object_ix_hashsz = nr_objects * 3;
+ if (object_ix_hashsz < 1024)
+ object_ix_hashsz = 1024;
+ object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
+ object_ix = memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
+ for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
+ int ix = locate_object_entry_hash(oe->sha1);
+ if (0 <= ix)
+ continue;
+ ix = -1 - ix;
+ object_ix[ix] = i + 1;
+ }
+}
+
+static int add_object_entry(const unsigned char *sha1, const char *name, int exclude)
+{
+ unsigned int hash = 0;
unsigned int idx = nr_objects;
struct object_entry *entry;
+ struct packed_git *p;
+ unsigned int found_offset = 0;
+ struct packed_git *found_pack = NULL;
+ int ix;
+
+ if (!exclude) {
+ for (p = packed_git; p; p = p->next) {
+ struct pack_entry e;
+ if (find_pack_entry_one(sha1, &e, p)) {
+ if (incremental)
+ return 0;
+ if (local && !p->pack_local)
+ return 0;
+ if (!found_pack) {
+ found_offset = e.offset;
+ found_pack = e.p;
+ }
+ }
+ }
+ }
+ if ((entry = locate_object_entry(sha1)) != NULL)
+ goto already_added;
+
+ while (*name) {
+ unsigned char c = *name++;
+ if (isspace(c))
+ continue;
+ hash = hash * 11 + c;
+ }
if (idx >= nr_alloc) {
unsigned int needed = (idx + 1024) * 3 / 2;
nr_alloc = needed;
}
entry = objects + idx;
+ nr_objects = idx + 1;
memset(entry, 0, sizeof(*entry));
memcpy(entry->sha1, sha1, 20);
- nr_objects = idx+1;
+ entry->hash = hash;
+
+ if (object_ix_hashsz * 3 <= nr_objects * 4)
+ rehash_objects();
+ else {
+ ix = locate_object_entry_hash(entry->sha1);
+ if (0 <= ix)
+ die("internal error in object hashing.");
+ object_ix[-1 - ix] = idx + 1;
+ }
+
+ already_added:
+ if (exclude)
+ entry->preferred_base = 1;
+ else {
+ if (found_pack) {
+ entry->in_pack = found_pack;
+ entry->in_pack_offset = found_offset;
+ }
+ }
+ return 1;
+}
+
+static void add_pbase_tree(struct tree_desc *tree)
+{
+ while (tree->size) {
+ const unsigned char *sha1;
+ const char *name;
+ unsigned mode;
+ unsigned long size;
+ char type[20];
+
+ sha1 = tree_entry_extract(tree, &name, &mode);
+ update_tree_entry(tree);
+ if (!has_sha1_file(sha1))
+ continue;
+ if (sha1_object_info(sha1, type, &size))
+ continue;
+ add_object_entry(sha1, name, 1);
+ if (!strcmp(type, "tree")) {
+ struct tree_desc sub;
+ void *elem;
+ elem = read_sha1_file(sha1, type, &sub.size);
+ sub.buf = elem;
+ if (sub.buf) {
+ add_pbase_tree(&sub);
+ free(elem);
+ }
+ }
+ }
+}
+
+static void add_preferred_base(unsigned char *sha1)
+{
+ struct tree_desc tree;
+ void *elem;
+ elem = read_object_with_reference(sha1, "tree", &tree.size, NULL);
+ tree.buf = elem;
+ if (!tree.buf)
+ return;
+ add_object_entry(sha1, "", 1);
+ add_pbase_tree(&tree);
+ free(elem);
}
static void check_object(struct object_entry *entry)
{
- char buffer[128];
- char type[10];
- unsigned long mapsize;
- z_stream stream;
- void *map;
-
- map = map_sha1_file(entry->sha1, &mapsize);
- if (!map)
- die("unable to map %s", sha1_to_hex(entry->sha1));
- if (unpack_sha1_header(&stream, map, mapsize, buffer, sizeof(buffer)) < 0)
- die("unable to unpack %s header", sha1_to_hex(entry->sha1));
- munmap(map, mapsize);
- if (parse_sha1_header(buffer, type, &entry->size) < 0)
- die("unable to parse %s header", sha1_to_hex(entry->sha1));
+ char type[20];
+
+ if (entry->in_pack && !entry->preferred_base) {
+ unsigned char base[20];
+ unsigned long size;
+ struct object_entry *base_entry;
+
+ /* We want in_pack_type even if we do not reuse delta.
+ * There is no point not reusing non-delta representations.
+ */
+ check_reuse_pack_delta(entry->in_pack,
+ entry->in_pack_offset,
+ base, &size,
+ &entry->in_pack_type);
+
+ /* Check if it is delta, and the base is also an object
+ * we are going to pack. If so we will reuse the existing
+ * delta.
+ */
+ if (!no_reuse_delta &&
+ entry->in_pack_type == OBJ_DELTA &&
+ (base_entry = locate_object_entry(base)) &&
+ (!base_entry->preferred_base)) {
+
+ /* Depth value does not matter - find_deltas()
+ * will never consider reused delta as the
+ * base object to deltify other objects
+ * against, in order to avoid circular deltas.
+ */
+
+ /* uncompressed size of the delta data */
+ entry->size = entry->delta_size = size;
+ entry->delta = base_entry;
+ entry->type = OBJ_DELTA;
+
+ entry->delta_sibling = base_entry->delta_child;
+ base_entry->delta_child = entry;
+
+ return;
+ }
+ /* Otherwise we would do the usual */
+ }
+
+ if (sha1_object_info(entry->sha1, type, &entry->size))
+ die("unable to get type of object %s",
+ sha1_to_hex(entry->sha1));
+
if (!strcmp(type, "commit")) {
entry->type = OBJ_COMMIT;
} else if (!strcmp(type, "tree")) {
entry->type = OBJ_TREE;
} else if (!strcmp(type, "blob")) {
entry->type = OBJ_BLOB;
+ } else if (!strcmp(type, "tag")) {
+ entry->type = OBJ_TAG;
} else
- die("unable to pack object %s of type %s", sha1_to_hex(entry->sha1), type);
+ die("unable to pack object %s of type %s",
+ sha1_to_hex(entry->sha1), type);
+}
+
+static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
+{
+ struct object_entry *child = me->delta_child;
+ unsigned int m = n;
+ while (child) {
+ unsigned int c = check_delta_limit(child, n + 1);
+ if (m < c)
+ m = c;
+ child = child->delta_sibling;
+ }
+ return m;
}
static void get_object_details(void)
{
int i;
- struct object_entry *entry = objects;
+ struct object_entry *entry;
- for (i = 0; i < nr_objects; i++)
- check_object(entry++);
+ prepare_pack_ix();
+ for (i = 0, entry = objects; i < nr_objects; i++, entry++)
+ check_object(entry);
+ for (i = 0, entry = objects; i < nr_objects; i++, entry++)
+ if (!entry->delta && entry->delta_child)
+ entry->delta_limit =
+ check_delta_limit(entry, 1);
}
typedef int (*entry_sort_t)(const struct object_entry *, const struct object_entry *);
return memcmp(a->sha1, b->sha1, 20);
}
+static struct object_entry **create_final_object_list()
+{
+ struct object_entry **list;
+ int i, j;
+
+ for (i = nr_result = 0; i < nr_objects; i++)
+ if (!objects[i].preferred_base)
+ nr_result++;
+ list = xmalloc(nr_result * sizeof(struct object_entry *));
+ for (i = j = 0; i < nr_objects; i++) {
+ if (!objects[i].preferred_base)
+ list[j++] = objects + i;
+ }
+ current_sort = sha1_sort;
+ qsort(list, nr_result, sizeof(struct object_entry *), sort_comparator);
+ return list;
+}
+
static int type_size_sort(const struct object_entry *a, const struct object_entry *b)
{
if (a->type < b->type)
return -1;
if (a->type > b->type)
return 1;
+ if (a->hash < b->hash)
+ return -1;
+ if (a->hash > b->hash)
+ return 1;
+ if (a->preferred_base < b->preferred_base)
+ return -1;
+ if (a->preferred_base > b->preferred_base)
+ return 1;
if (a->size < b->size)
return -1;
if (a->size > b->size)
};
/*
- * We search for deltas in a list sorted by type and by size, and
- * walk the "old" chain backwards in the list, so if the type
- * has changed or the size difference is too big, there's no point
- * in even continuing the walk, since the other old objects are
- * going to be even smaller or of a different type. So return -1
- * once we determine that there's no point even trying.
+ * We search for deltas _backwards_ in a list sorted by type and
+ * by size, so that we see progressively smaller and smaller files.
+ * That's because we prefer deltas to be from the bigger file
+ * to the smaller - deletes are potentially cheaper, but perhaps
+ * more importantly, the bigger file is likely the more recent
+ * one.
*/
static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_depth)
{
struct object_entry *cur_entry = cur->entry;
struct object_entry *old_entry = old->entry;
- unsigned long size, oldsize, delta_size;
+ int old_preferred = (old_entry->preferred_base ||
+ old_entry->based_on_preferred);
+ unsigned long size, oldsize, delta_size, sizediff;
long max_size;
void *delta_buf;
if (cur_entry->type != old_entry->type)
return -1;
- /* Size is guaranteed to be larger than or equal to oldsize */
+ /* We do not compute delta to *create* objects we are not
+ * going to pack.
+ */
+ if (cur_entry->preferred_base)
+ return -1;
+
+ /* If the current object is at pack edge, take the depth the
+ * objects that depend on the current object into account --
+ * otherwise they would become too deep.
+ */
+ if (cur_entry->delta_child) {
+ if (max_depth <= cur_entry->delta_limit)
+ return 0;
+ max_depth -= cur_entry->delta_limit;
+ }
+
size = cur_entry->size;
if (size < 50)
return -1;
oldsize = old_entry->size;
- if (size - oldsize > oldsize / 4)
+ sizediff = oldsize > size ? oldsize - size : size - oldsize;
+ if (sizediff > size / 8)
return -1;
if (old_entry->depth >= max_depth)
return 0;
* delete).
*/
max_size = size / 2 - 20;
- if (cur_entry->delta)
- max_size = cur_entry->delta_size-1;
+ if (cur_entry->delta) {
+ if (cur_entry->based_on_preferred) {
+ if (old_preferred)
+ max_size = cur_entry->delta_size-1;
+ else
+ /* trying with non-preferred one when we
+ * already have a delta based on preferred
+ * one is pointless.
+ */
+ return 0;
+ }
+ else if (!old_preferred)
+ max_size = cur_entry->delta_size-1;
+ else
+ /* otherwise... even if delta with a
+ * preferred one produces a bigger result than
+ * what we currently have, which is based on a
+ * non-preferred one, it is OK.
+ */
+ ;
+ }
+ if (sizediff >= max_size)
+ return -1;
delta_buf = diff_delta(old->data, oldsize,
cur->data, size, &delta_size, max_size);
if (!delta_buf)
cur_entry->delta = old_entry;
cur_entry->delta_size = delta_size;
cur_entry->depth = old_entry->depth + 1;
+ cur_entry->based_on_preferred = old_preferred;
free(delta_buf);
return 0;
}
static void find_deltas(struct object_entry **list, int window, int depth)
{
- unsigned int i;
+ int i, idx;
unsigned int array_size = window * sizeof(struct unpacked);
struct unpacked *array = xmalloc(array_size);
+ int eye_candy;
memset(array, 0, array_size);
- for (i = 0; i < nr_objects; i++) {
- unsigned int idx = i % window;
+ i = nr_objects;
+ idx = 0;
+ eye_candy = i - (nr_objects / 20);
+
+ while (--i >= 0) {
struct object_entry *entry = list[i];
struct unpacked *n = array + idx;
unsigned long size;
char type[10];
int j;
+ if (progress && i <= eye_candy) {
+ eye_candy -= nr_objects / 20;
+ fputc('.', stderr);
+ }
+
+ if (entry->delta)
+ /* This happens if we decided to reuse existing
+ * delta from a pack. "!no_reuse_delta &&" is implied.
+ */
+ continue;
+
free(n->data);
n->entry = entry;
n->data = read_sha1_file(entry->sha1, type, &size);
if (size != entry->size)
die("object %s inconsistent object length (%lu vs %lu)", sha1_to_hex(entry->sha1), size, entry->size);
+
j = window;
while (--j > 0) {
unsigned int other_idx = idx + j;
if (try_delta(n, m, depth) < 0)
break;
}
+ idx++;
+ if (idx >= window)
+ idx = 0;
}
+
+ for (i = 0; i < window; ++i)
+ free(array[i].data);
+ free(array);
+}
+
+static void prepare_pack(int window, int depth)
+{
+ if (progress)
+ fprintf(stderr, "Packing %d objects", nr_result);
+ get_object_details();
+ if (progress)
+ fputc('.', stderr);
+
+ sorted_by_type = create_sorted_list(type_size_sort);
+ if (window && depth)
+ find_deltas(sorted_by_type, window+1, depth);
+ if (progress)
+ fputc('\n', stderr);
+ write_pack_file();
+}
+
+static int reuse_cached_pack(unsigned char *sha1, int pack_to_stdout)
+{
+ static const char cache[] = "pack-cache/pack-%s.%s";
+ char *cached_pack, *cached_idx;
+ int ifd, ofd, ifd_ix = -1;
+
+ cached_pack = git_path(cache, sha1_to_hex(sha1), "pack");
+ ifd = open(cached_pack, O_RDONLY);
+ if (ifd < 0)
+ return 0;
+
+ if (!pack_to_stdout) {
+ cached_idx = git_path(cache, sha1_to_hex(sha1), "idx");
+ ifd_ix = open(cached_idx, O_RDONLY);
+ if (ifd_ix < 0) {
+ close(ifd);
+ return 0;
+ }
+ }
+
+ if (progress)
+ fprintf(stderr, "Reusing %d objects pack %s\n", nr_objects,
+ sha1_to_hex(sha1));
+
+ if (pack_to_stdout) {
+ if (copy_fd(ifd, 1))
+ exit(1);
+ close(ifd);
+ }
+ else {
+ char name[PATH_MAX];
+ snprintf(name, sizeof(name),
+ "%s-%s.%s", base_name, sha1_to_hex(sha1), "pack");
+ ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666);
+ if (ofd < 0)
+ die("unable to open %s (%s)", name, strerror(errno));
+ if (copy_fd(ifd, ofd))
+ exit(1);
+ close(ifd);
+
+ snprintf(name, sizeof(name),
+ "%s-%s.%s", base_name, sha1_to_hex(sha1), "idx");
+ ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666);
+ if (ofd < 0)
+ die("unable to open %s (%s)", name, strerror(errno));
+ if (copy_fd(ifd_ix, ofd))
+ exit(1);
+ close(ifd_ix);
+ puts(sha1_to_hex(sha1));
+ }
+
+ return 1;
}
int main(int argc, char **argv)
{
- char line[128];
- int window = 10, depth = 10;
+ SHA_CTX ctx;
+ char line[PATH_MAX + 20];
+ int window = 10, depth = 10, pack_to_stdout = 0;
+ struct object_entry **list;
int i;
+ struct timeval prev_tv;
+ int eye_candy = 0;
+ int eye_candy_incr = 500;
+
+
+ setup_git_directory();
for (i = 1; i < argc; i++) {
const char *arg = argv[i];
if (*arg == '-') {
+ if (!strcmp("--non-empty", arg)) {
+ non_empty = 1;
+ continue;
+ }
+ if (!strcmp("--local", arg)) {
+ local = 1;
+ continue;
+ }
+ if (!strcmp("--incremental", arg)) {
+ incremental = 1;
+ continue;
+ }
if (!strncmp("--window=", arg, 9)) {
char *end;
window = strtoul(arg+9, &end, 0);
usage(pack_usage);
continue;
}
+ if (!strcmp("-q", arg)) {
+ progress = 0;
+ continue;
+ }
+ if (!strcmp("--no-reuse-delta", arg)) {
+ no_reuse_delta = 1;
+ continue;
+ }
+ if (!strcmp("--stdout", arg)) {
+ pack_to_stdout = 1;
+ continue;
+ }
usage(pack_usage);
}
if (base_name)
base_name = arg;
}
- if (!base_name)
+ if (pack_to_stdout != !base_name)
usage(pack_usage);
+ prepare_packed_git();
+ if (progress) {
+ fprintf(stderr, "Generating pack...\n");
+ gettimeofday(&prev_tv, NULL);
+ }
while (fgets(line, sizeof(line), stdin) != NULL) {
unsigned char sha1[20];
+
+ if (progress && (eye_candy <= nr_objects)) {
+ fprintf(stderr, "Counting objects...%d\r", nr_objects);
+ if (eye_candy && (50 <= eye_candy_incr)) {
+ struct timeval tv;
+ int time_diff;
+ gettimeofday(&tv, NULL);
+ time_diff = (tv.tv_sec - prev_tv.tv_sec);
+ time_diff <<= 10;
+ time_diff += (tv.tv_usec - prev_tv.tv_usec);
+ if ((1 << 9) < time_diff)
+ eye_candy_incr += 50;
+ else if (50 < eye_candy_incr)
+ eye_candy_incr -= 50;
+ }
+ eye_candy += eye_candy_incr;
+ }
+ if (line[0] == '-') {
+ if (get_sha1_hex(line+1, sha1))
+ die("expected edge sha1, got garbage:\n %s",
+ line+1);
+ add_preferred_base(sha1);
+ continue;
+ }
if (get_sha1_hex(line, sha1))
- die("expected sha1, got garbage");
- add_object_entry(sha1);
+ die("expected sha1, got garbage:\n %s", line);
+ add_object_entry(sha1, line+40, 0);
}
- get_object_details();
-
- printf("Packing %d objects\n", nr_objects);
+ if (progress)
+ fprintf(stderr, "Done counting %d objects.\n", nr_objects);
+ if (non_empty && !nr_objects)
+ return 0;
- sorted_by_sha = create_sorted_list(sha1_sort);
- sorted_by_type = create_sorted_list(type_size_sort);
- if (window && depth)
- find_deltas(sorted_by_type, window+1, depth);
+ sorted_by_sha = create_final_object_list();
+ SHA1_Init(&ctx);
+ list = sorted_by_sha;
+ for (i = 0; i < nr_result; i++) {
+ struct object_entry *entry = *list++;
+ SHA1_Update(&ctx, entry->sha1, 20);
+ }
+ SHA1_Final(object_list_sha1, &ctx);
+ if (progress && (nr_objects != nr_result))
+ fprintf(stderr, "Result has %d objects.\n", nr_result);
- write_pack_file();
- write_index_file();
+ if (reuse_cached_pack(object_list_sha1, pack_to_stdout))
+ ;
+ else {
+ prepare_pack(window, depth);
+ if (!pack_to_stdout) {
+ write_index_file();
+ puts(sha1_to_hex(object_list_sha1));
+ }
+ }
+ if (progress)
+ fprintf(stderr, "Total %d, written %d (delta %d), reused %d (delta %d)\n",
+ nr_result, written, written_delta, reused, reused_delta);
return 0;
}