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-rw-r--r--mkdelta.c364
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;
-}
generated by cgit v1.2.3 (git 2.25.1) at 2024-08-03 05:17:22 +0300