git

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#include "builtin.h"
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#include "gettext.h"
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#include "hash.h"
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#include "hex.h"
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#include "pack.h"
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#include "parse-options.h"
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#include "repository.h"
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static const char *const show_index_usage[] = {
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	"git show-index [--object-format=<hash-algorithm>]",
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	NULL
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};
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int cmd_show_index(int argc, const char **argv, const char *prefix)
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{
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	int i;
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	unsigned nr;
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	unsigned int version;
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	static unsigned int top_index[256];
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	unsigned hashsz;
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	const char *hash_name = NULL;
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	int hash_algo;
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	const struct option show_index_options[] = {
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		OPT_STRING(0, "object-format", &hash_name, N_("hash-algorithm"),
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			   N_("specify the hash algorithm to use")),
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		OPT_END()
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	};
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	argc = parse_options(argc, argv, prefix, show_index_options, show_index_usage, 0);
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	if (hash_name) {
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		hash_algo = hash_algo_by_name(hash_name);
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		if (hash_algo == GIT_HASH_UNKNOWN)
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			die(_("Unknown hash algorithm"));
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		repo_set_hash_algo(the_repository, hash_algo);
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	}
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	hashsz = the_hash_algo->rawsz;
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	if (fread(top_index, 2 * 4, 1, stdin) != 1)
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		die("unable to read header");
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	if (top_index[0] == htonl(PACK_IDX_SIGNATURE)) {
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		version = ntohl(top_index[1]);
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		if (version < 2 || version > 2)
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			die("unknown index version");
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		if (fread(top_index, 256 * 4, 1, stdin) != 1)
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			die("unable to read index");
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	} else {
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		version = 1;
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		if (fread(&top_index[2], 254 * 4, 1, stdin) != 1)
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			die("unable to read index");
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	}
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	nr = 0;
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	for (i = 0; i < 256; i++) {
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		unsigned n = ntohl(top_index[i]);
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		if (n < nr)
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			die("corrupt index file");
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		nr = n;
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	}
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	if (version == 1) {
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		for (i = 0; i < nr; i++) {
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			unsigned int offset, entry[(GIT_MAX_RAWSZ + 4) / sizeof(unsigned int)];
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			if (fread(entry, 4 + hashsz, 1, stdin) != 1)
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				die("unable to read entry %u/%u", i, nr);
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			offset = ntohl(entry[0]);
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			printf("%u %s\n", offset, hash_to_hex((void *)(entry+1)));
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		}
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	} else {
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		unsigned off64_nr = 0;
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		struct {
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			struct object_id oid;
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			uint32_t crc;
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			uint32_t off;
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		} *entries;
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		ALLOC_ARRAY(entries, nr);
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		for (i = 0; i < nr; i++) {
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			if (fread(entries[i].oid.hash, hashsz, 1, stdin) != 1)
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				die("unable to read sha1 %u/%u", i, nr);
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			entries[i].oid.algo = hash_algo_by_ptr(the_hash_algo);
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		}
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		for (i = 0; i < nr; i++)
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			if (fread(&entries[i].crc, 4, 1, stdin) != 1)
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				die("unable to read crc %u/%u", i, nr);
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		for (i = 0; i < nr; i++)
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			if (fread(&entries[i].off, 4, 1, stdin) != 1)
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				die("unable to read 32b offset %u/%u", i, nr);
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		for (i = 0; i < nr; i++) {
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			uint64_t offset;
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			uint32_t off = ntohl(entries[i].off);
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			if (!(off & 0x80000000)) {
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				offset = off;
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			} else {
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				uint32_t off64[2];
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				if ((off & 0x7fffffff) != off64_nr)
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					die("inconsistent 64b offset index");
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				if (fread(off64, 8, 1, stdin) != 1)
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					die("unable to read 64b offset %u", off64_nr);
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				offset = (((uint64_t)ntohl(off64[0])) << 32) |
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						     ntohl(off64[1]);
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				off64_nr++;
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			}
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			printf("%" PRIuMAX " %s (%08"PRIx32")\n",
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			       (uintmax_t) offset,
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			       oid_to_hex(&entries[i].oid),
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			       ntohl(entries[i].crc));
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		}
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		free(entries);
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	}
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	return 0;
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}
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