diff options
Diffstat (limited to 'mkdelta.c')
| -rw-r--r-- | mkdelta.c | 364 |
1 files changed, 0 insertions, 364 deletions
diff --git a/mkdelta.c b/mkdelta.c deleted file mode 100644 index d4c5f3b4ec..0000000000 --- a/mkdelta.c +++ /dev/null @@ -1,364 +0,0 @@ -/* - * Deltafication of a GIT database. - * - * (C) 2005 Nicolas Pitre <nico@cam.org> - * - * This code is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - */ - -#include "cache.h" -#include "delta.h" - -static int replace_object(char *buf, unsigned long size, unsigned char *sha1) -{ - char tmpfile[PATH_MAX]; - int fd; - - snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory()); - fd = mkstemp(tmpfile); - if (fd < 0) - return error("%s: %s\n", tmpfile, strerror(errno)); - if (write(fd, buf, size) != size) { - perror("unable to write file"); - close(fd); - unlink(tmpfile); - return -1; - } - fchmod(fd, 0444); - close(fd); - if (rename(tmpfile, sha1_file_name(sha1))) { - perror("unable to replace original object"); - unlink(tmpfile); - return -1; - } - return 0; -} - -static void *create_object(unsigned char *buf, unsigned long len, - char *hdr, int hdrlen, unsigned long *retsize) -{ - unsigned char *compressed; - unsigned long size; - z_stream stream; - - /* Set it up */ - memset(&stream, 0, sizeof(stream)); - deflateInit(&stream, Z_BEST_COMPRESSION); - size = deflateBound(&stream, len+hdrlen); - compressed = xmalloc(size); - - /* Compress it */ - stream.next_out = compressed; - stream.avail_out = size; - - /* First header.. */ - stream.next_in = (unsigned char *)hdr; - stream.avail_in = hdrlen; - while (deflate(&stream, 0) == Z_OK) - /* nothing */; - - /* Then the data itself.. */ - stream.next_in = buf; - stream.avail_in = len; - while (deflate(&stream, Z_FINISH) == Z_OK) - /* nothing */; - deflateEnd(&stream); - *retsize = stream.total_out; - return compressed; -} - -static int restore_original_object(unsigned char *buf, unsigned long len, - char *type, unsigned char *sha1) -{ - char hdr[50]; - int hdrlen, ret; - void *compressed; - unsigned long size; - - hdrlen = sprintf(hdr, "%s %lu", type, len)+1; - compressed = create_object(buf, len, hdr, hdrlen, &size); - ret = replace_object(compressed, size, sha1); - free(compressed); - return ret; -} - -static void *create_delta_object(unsigned char *buf, unsigned long len, - unsigned char *sha1_ref, unsigned long *size) -{ - char hdr[50]; - int hdrlen; - - /* Generate the header + sha1 of reference for delta */ - hdrlen = sprintf(hdr, "delta %lu", len+20)+1; - memcpy(hdr + hdrlen, sha1_ref, 20); - hdrlen += 20; - - return create_object(buf, len, hdr, hdrlen, size); -} - -static void *get_buffer(unsigned char *sha1, char *type, - unsigned long *size, unsigned long *compsize) -{ - unsigned long mapsize; - void *map = map_sha1_file(sha1, &mapsize); - if (map) { - void *buffer = unpack_sha1_file(map, mapsize, type, size); - munmap(map, mapsize); - if (compsize) - *compsize = mapsize; - if (buffer) - return buffer; - } - error("unable to get object %s", sha1_to_hex(sha1)); - return NULL; -} - -static void *expand_delta(void *delta, unsigned long *size, char *type, - unsigned int *depth, unsigned char **links) -{ - void *buf = NULL; - unsigned int level = (*depth)++; - if (*size < 20) { - error("delta object is bad"); - free(delta); - } else { - unsigned long ref_size; - void *ref = get_buffer(delta, type, &ref_size, NULL); - if (ref && !strcmp(type, "delta")) - ref = expand_delta(ref, &ref_size, type, depth, links); - else if (ref) -{ - *links = xmalloc(*depth * 20); -} - if (ref) { - buf = patch_delta(ref, ref_size, delta+20, *size-20, size); - free(ref); - if (buf) - memcpy(*links + level*20, delta, 20); - else - free(*links); - } - free(delta); - } - return buf; -} - -static char *mkdelta_usage = -"mkdelta [--max-depth=N] [--max-behind=N] <reference_sha1> <target_sha1> [<next_sha1> ...]"; - -struct delta { - unsigned char sha1[20]; /* object sha1 */ - unsigned long size; /* object size */ - void *buf; /* object content */ - unsigned char *links; /* delta reference links */ - unsigned int depth; /* delta depth */ -}; - -int main(int argc, char **argv) -{ - struct delta *ref, trg; - char ref_type[20], trg_type[20], *skip_reason; - void *best_buf; - unsigned long best_size, orig_size, orig_compsize; - unsigned int r, orig_ref, best_ref, nb_refs, next_ref, max_refs = 0; - unsigned int i, duplicate, skip_lvl, verbose = 0, quiet = 0; - unsigned int max_depth = -1; - - for (i = 1; i < argc; i++) { - if (!strcmp(argv[i], "-v")) { - verbose = 1; - quiet = 0; - } else if (!strcmp(argv[i], "-q")) { - quiet = 1; - verbose = 0; - } else if (!strcmp(argv[i], "-d") && i+1 < argc) { - max_depth = atoi(argv[++i]); - } else if (!strncmp(argv[i], "--max-depth=", 12)) { - max_depth = atoi(argv[i]+12); - } else if (!strcmp(argv[i], "-b") && i+1 < argc) { - max_refs = atoi(argv[++i]); - } else if (!strncmp(argv[i], "--max-behind=", 13)) { - max_refs = atoi(argv[i]+13); - } else - break; - } - - if (i + (max_depth != 0) >= argc) - usage(mkdelta_usage); - - if (!max_refs || max_refs > argc - i) - max_refs = argc - i; - ref = xmalloc(max_refs * sizeof(*ref)); - for (r = 0; r < max_refs; r++) - ref[r].buf = ref[r].links = NULL; - next_ref = nb_refs = 0; - - do { - if (get_sha1(argv[i], trg.sha1)) - die("bad sha1 %s", argv[i]); - trg.buf = get_buffer(trg.sha1, trg_type, &trg.size, &orig_compsize); - if (trg.buf && !trg.size) { - if (verbose) - printf("skip %s (object is empty)\n", argv[i]); - continue; - } - orig_size = trg.size; - orig_ref = -1; - trg.depth = 0; - trg.links = NULL; - if (trg.buf && !strcmp(trg_type, "delta")) { - for (r = 0; r < nb_refs; r++) - if (!memcmp(trg.buf, ref[r].sha1, 20)) - break; - if (r < nb_refs) { - /* no need to reload the reference object */ - trg.depth = ref[r].depth + 1; - trg.links = xmalloc(trg.depth*20); - memcpy(trg.links, trg.buf, 20); - memcpy(trg.links+20, ref[r].links, ref[r].depth*20); - trg.buf = patch_delta(ref[r].buf, ref[r].size, - trg.buf+20, trg.size-20, - &trg.size); - strcpy(trg_type, ref_type); - orig_ref = r; - } else { - trg.buf = expand_delta(trg.buf, &trg.size, trg_type, - &trg.depth, &trg.links); - } - } - if (!trg.buf) - die("unable to read target object %s", argv[i]); - - if (!nb_refs) { - strcpy(ref_type, trg_type); - } else if (max_depth && strcmp(ref_type, trg_type)) { - die("type mismatch for object %s", argv[i]); - } - - duplicate = 0; - best_buf = NULL; - best_size = -1; - best_ref = -1; - skip_lvl = 0; - skip_reason = NULL; - for (r = 0; max_depth && r < nb_refs; r++) { - void *delta_buf, *comp_buf; - unsigned long delta_size, comp_size; - unsigned int l; - - duplicate = !memcmp(trg.sha1, ref[r].sha1, 20); - if (duplicate) { - skip_reason = "already seen"; - break; - } - if (ref[r].depth >= max_depth) { - if (skip_lvl < 1) { - skip_reason = "exceeding max link depth"; - skip_lvl = 1; - } - continue; - } - for (l = 0; l < ref[r].depth; l++) - if (!memcmp(trg.sha1, ref[r].links + l*20, 20)) - break; - if (l != ref[r].depth) { - if (skip_lvl < 2) { - skip_reason = "would create a loop"; - skip_lvl = 2; - } - continue; - } - if (trg.depth < max_depth && r == orig_ref) { - if (skip_lvl < 3) { - skip_reason = "delta already in place"; - skip_lvl = 3; - } - continue; - } - delta_buf = diff_delta(ref[r].buf, ref[r].size, - trg.buf, trg.size, - &delta_size, ~0UL); - if (!delta_buf) - die("out of memory"); - if (trg.depth < max_depth && - delta_size+20 >= orig_size) { - /* no need to even try to compress if original - object is smaller than this delta */ - free(delta_buf); - if (skip_lvl < 4) { - skip_reason = "no size reduction"; - skip_lvl = 4; - } - continue; - } - comp_buf = create_delta_object(delta_buf, delta_size, - ref[r].sha1, &comp_size); - if (!comp_buf) - die("out of memory"); - free(delta_buf); - if (trg.depth < max_depth && - comp_size >= orig_compsize) { - free(comp_buf); - if (skip_lvl < 5) { - skip_reason = "no size reduction"; - skip_lvl = 5; - } - continue; - } - if ((comp_size < best_size) || - (comp_size == best_size && - ref[r].depth < ref[best_ref].depth)) { - free(best_buf); - best_buf = comp_buf; - best_size = comp_size; - best_ref = r; - } - } - - if (best_buf) { - if (replace_object(best_buf, best_size, trg.sha1)) - die("unable to write delta for %s", argv[i]); - free(best_buf); - free(trg.links); - trg.depth = ref[best_ref].depth + 1; - trg.links = xmalloc(trg.depth*20); - memcpy(trg.links, ref[best_ref].sha1, 20); - memcpy(trg.links+20, ref[best_ref].links, ref[best_ref].depth*20); - if (!quiet) - printf("delta %s (size=%ld.%02ld%% depth=%d dist=%d)\n", - argv[i], best_size*100 / orig_compsize, - (best_size*10000 / orig_compsize)%100, - trg.depth, - (next_ref - best_ref + max_refs) - % (max_refs + 1) + 1); - } else if (trg.depth > max_depth) { - if (restore_original_object(trg.buf, trg.size, trg_type, trg.sha1)) - die("unable to restore %s", argv[i]); - if (!quiet) - printf("undelta %s (depth was %d)\n", - argv[i], trg.depth); - trg.depth = 0; - free(trg.links); - trg.links = NULL; - } else if (skip_reason && verbose) { - printf("skip %s (%s)\n", argv[i], skip_reason); - } - - if (!duplicate) { - free(ref[next_ref].buf); - free(ref[next_ref].links); - ref[next_ref] = trg; - if (++next_ref > nb_refs) - nb_refs = next_ref; - if (next_ref == max_refs) - next_ref = 0; - } else { - free(trg.buf); - free(trg.links); - } - } while (++i < argc); - - return 0; -} |