#include "cache.h"
#include "object.h"
-#include "delta.h"
+#include "pack.h"
+#include "pack-objects.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
-};
-
-struct object_entry {
- unsigned char sha1[20];
- unsigned long size;
- unsigned long offset;
- unsigned int depth;
- unsigned int flags;
- enum object_type type;
- unsigned long delta_size;
- struct object_entry *delta;
-};
-
-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 const char *base_name;
-
-struct myfile {
- int fd;
- unsigned long chars;
- unsigned char buffer[8192];
-};
-
-static FILE *create_file(const char *suffix)
-{
- static char filename[PATH_MAX];
- unsigned len;
-
- len = snprintf(filename, PATH_MAX, "%s.%s", base_name, suffix);
- if (len >= PATH_MAX)
- die("you wascally wabbit, you");
- return fopen(filename, "w");
-}
-
-static unsigned long fwrite_compressed(void *in, unsigned long size, FILE *f)
-{
- 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;
-}
-
-static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
-{
- unsigned long othersize, delta_size;
- char type[10];
- void *otherbuf = read_sha1_file(entry->delta->sha1, type, &othersize);
- void *delta_buf;
-
- if (!otherbuf)
- die("unable to read %s", sha1_to_hex(entry->delta->sha1));
- delta_buf = diff_delta(otherbuf, othersize,
- buf, size, &delta_size, ~0UL);
- if (!delta_buf || delta_size != entry->delta_size)
- die("delta size changed");
- free(buf);
- free(otherbuf);
- return delta_buf;
-}
-
-static unsigned long write_object(FILE *f, struct object_entry *entry)
+static uint32_t locate_object_entry_hash(struct packing_data *pdata,
+ const unsigned char *sha1,
+ int *found)
{
- unsigned long size;
- char type[10];
- void *buf = read_sha1_file(entry->sha1, type, &size);
- char header[25];
- unsigned hdrlen, datalen;
+ uint32_t i, hash, mask = (pdata->index_size - 1);
- 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);
+ memcpy(&hash, sha1, sizeof(uint32_t));
+ i = hash & mask;
- /*
- * 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;
- }
- datalen = htonl(size);
- memcpy(header+1, &datalen, 4);
- fwrite(header, hdrlen, 1, f);
- datalen = fwrite_compressed(buf, size, f);
- free(buf);
- return hdrlen + datalen;
-}
-
-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;
-}
-
-static void write_index_file(void)
-{
- int i;
- FILE *f = create_file("idx");
- struct object_entry **list = sorted_by_sha;
- struct object_entry **last = list + nr_objects;
- unsigned int array[256];
+ while (pdata->index[i] > 0) {
+ uint32_t pos = pdata->index[i] - 1;
- /*
- * 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)
- */
- for (i = 0; i < 256; i++) {
- struct object_entry **next = list;
- while (next < last) {
- struct object_entry *entry = *next;
- if (entry->sha1[0] != i)
- break;
- next++;
+ if (!hashcmp(sha1, pdata->objects[pos].idx.sha1)) {
+ *found = 1;
+ return i;
}
- array[i] = htonl(next - sorted_by_sha);
- list = next;
- }
- fwrite(array, 256, sizeof(int), f);
- /*
- * Write the actual SHA1 entries..
- */
- list = sorted_by_sha;
- for (i = 0; i < nr_objects; i++) {
- struct object_entry *entry = *list++;
- unsigned int offset = htonl(entry->offset);
- fwrite(&offset, 4, 1, f);
- fwrite(entry->sha1, 20, 1, f);
+ i = (i + 1) & mask;
}
- fclose(f);
-}
-
-static void add_object_entry(unsigned char *sha1)
-{
- unsigned int idx = nr_objects;
- struct object_entry *entry;
- if (idx >= nr_alloc) {
- unsigned int needed = (idx + 1024) * 3 / 2;
- objects = xrealloc(objects, needed * sizeof(*entry));
- nr_alloc = needed;
- }
- entry = objects + idx;
- memset(entry, 0, sizeof(*entry));
- memcpy(entry->sha1, sha1, 20);
- nr_objects = idx+1;
+ *found = 0;
+ return i;
}
-static void check_object(struct object_entry *entry)
+static inline uint32_t closest_pow2(uint32_t v)
{
- 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));
- 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
- die("unable to pack object %s of type %s", sha1_to_hex(entry->sha1), type);
+ v = v - 1;
+ v |= v >> 1;
+ v |= v >> 2;
+ v |= v >> 4;
+ v |= v >> 8;
+ v |= v >> 16;
+ return v + 1;
}
-static void get_object_details(void)
+static void rehash_objects(struct packing_data *pdata)
{
- int i;
- struct object_entry *entry = objects;
-
- for (i = 0; i < nr_objects; i++)
- check_object(entry++);
-}
+ uint32_t i;
+ struct object_entry *entry;
-typedef int (*entry_sort_t)(const struct object_entry *, const struct object_entry *);
+ pdata->index_size = closest_pow2(pdata->nr_objects * 3);
+ if (pdata->index_size < 1024)
+ pdata->index_size = 1024;
-static entry_sort_t current_sort;
+ free(pdata->index);
+ pdata->index = xcalloc(pdata->index_size, sizeof(*pdata->index));
-static int sort_comparator(const void *_a, const void *_b)
-{
- struct object_entry *a = *(struct object_entry **)_a;
- struct object_entry *b = *(struct object_entry **)_b;
- return current_sort(a,b);
-}
+ entry = pdata->objects;
-static struct object_entry **create_sorted_list(entry_sort_t sort)
-{
- struct object_entry **list = xmalloc(nr_objects * sizeof(struct object_entry *));
- int i;
-
- for (i = 0; i < nr_objects; i++)
- list[i] = objects + i;
- current_sort = sort;
- qsort(list, nr_objects, sizeof(struct object_entry *), sort_comparator);
- return list;
-}
+ for (i = 0; i < pdata->nr_objects; i++) {
+ int found;
+ uint32_t ix = locate_object_entry_hash(pdata, entry->idx.sha1, &found);
-static int sha1_sort(const struct object_entry *a, const struct object_entry *b)
-{
- return memcmp(a->sha1, b->sha1, 20);
-}
+ if (found)
+ die("BUG: Duplicate object in hash");
-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->size < b->size)
- return -1;
- if (a->size > b->size)
- return 1;
- return a < b ? -1 : (a > b);
+ pdata->index[ix] = i + 1;
+ entry++;
+ }
}
-struct unpacked {
- struct object_entry *entry;
- void *data;
-};
-
-/*
- * 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.
- */
-static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_depth)
+struct object_entry *packlist_find(struct packing_data *pdata,
+ const unsigned char *sha1,
+ uint32_t *index_pos)
{
- struct object_entry *cur_entry = cur->entry;
- struct object_entry *old_entry = old->entry;
- unsigned long size, oldsize, delta_size;
- long max_size;
- void *delta_buf;
+ uint32_t i;
+ int found;
- /* Don't bother doing diffs between different types */
- if (cur_entry->type != old_entry->type)
- return -1;
+ if (!pdata->index_size)
+ return NULL;
- /* Size is guaranteed to be larger than or equal to oldsize */
- size = cur_entry->size;
- if (size < 50)
- return -1;
- oldsize = old_entry->size;
- if (size - oldsize > oldsize / 4)
- return -1;
- if (old_entry->depth >= max_depth)
- return 0;
+ i = locate_object_entry_hash(pdata, sha1, &found);
- /*
- * NOTE!
- *
- * We always delta from the bigger to the smaller, since that's
- * more space-efficient (deletes don't have to say _what_ they
- * delete).
- */
- max_size = size / 2 - 20;
- if (cur_entry->delta)
- max_size = cur_entry->delta_size-1;
- delta_buf = diff_delta(old->data, oldsize,
- cur->data, size, &delta_size, max_size);
- if (!delta_buf)
- return 0;
- cur_entry->delta = old_entry;
- cur_entry->delta_size = delta_size;
- cur_entry->depth = old_entry->depth + 1;
- free(delta_buf);
- return 0;
-}
+ if (index_pos)
+ *index_pos = i;
-static void find_deltas(struct object_entry **list, int window, int depth)
-{
- unsigned int i;
- unsigned int array_size = window * sizeof(struct unpacked);
- struct unpacked *array = xmalloc(array_size);
+ if (!found)
+ return NULL;
- memset(array, 0, array_size);
- for (i = 0; i < nr_objects; i++) {
- unsigned int idx = i % window;
- struct object_entry *entry = list[i];
- struct unpacked *n = array + idx;
- unsigned long size;
- char type[10];
- int j;
-
- 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;
- struct unpacked *m;
- if (other_idx >= window)
- other_idx -= window;
- m = array + other_idx;
- if (!m->entry)
- break;
- if (try_delta(n, m, depth) < 0)
- break;
- }
- }
+ return &pdata->objects[pdata->index[i] - 1];
}
-int main(int argc, char **argv)
+struct object_entry *packlist_alloc(struct packing_data *pdata,
+ const unsigned char *sha1,
+ uint32_t index_pos)
{
- char line[128];
- int window = 10, depth = 10;
- int i;
-
- for (i = 1; i < argc; i++) {
- const char *arg = argv[i];
+ struct object_entry *new_entry;
- if (*arg == '-') {
- if (!strncmp("--window=", arg, 9)) {
- char *end;
- window = strtoul(arg+9, &end, 0);
- if (!arg[9] || *end)
- usage(pack_usage);
- continue;
- }
- if (!strncmp("--depth=", arg, 8)) {
- char *end;
- depth = strtoul(arg+8, &end, 0);
- if (!arg[8] || *end)
- usage(pack_usage);
- continue;
- }
- usage(pack_usage);
- }
- if (base_name)
- usage(pack_usage);
- base_name = arg;
+ if (pdata->nr_objects >= pdata->nr_alloc) {
+ pdata->nr_alloc = (pdata->nr_alloc + 1024) * 3 / 2;
+ pdata->objects = xrealloc(pdata->objects,
+ pdata->nr_alloc * sizeof(*new_entry));
}
- if (!base_name)
- usage(pack_usage);
-
- while (fgets(line, sizeof(line), stdin) != NULL) {
- unsigned char sha1[20];
- if (get_sha1_hex(line, sha1))
- die("expected sha1, got garbage");
- add_object_entry(sha1);
- }
- get_object_details();
+ new_entry = pdata->objects + pdata->nr_objects++;
- printf("Packing %d objects\n", nr_objects);
+ memset(new_entry, 0, sizeof(*new_entry));
+ hashcpy(new_entry->idx.sha1, sha1);
- 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);
+ if (pdata->index_size * 3 <= pdata->nr_objects * 4)
+ rehash_objects(pdata);
+ else
+ pdata->index[index_pos] = pdata->nr_objects;
- write_pack_file();
- write_index_file();
- return 0;
+ return new_entry;
}