mirror of
https://github.com/git/git.git
synced 2024-11-01 06:47:52 +01:00
671fe4bb20
This is actually subtly wrong. If a short match is found in the object directory, but would _also_ match another SHA1 ID in a pack (or it shows in one pack but not another), we'll never have done the pack lookup, and we think it's unique. I can't find it in myself to care. You really want to use enough of a SHA1 that there is never any ambiguity.
366 lines
6.7 KiB
C
366 lines
6.7 KiB
C
/*
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* rev-parse.c
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*
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* Copyright (C) Linus Torvalds, 2005
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*/
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#include "cache.h"
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#include "commit.h"
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#include "refs.h"
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static char *def = NULL;
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static int no_revs = 0;
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static int single_rev = 0;
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static int revs_only = 0;
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static int do_rev_argument = 1;
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static int output_revs = 0;
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#define NORMAL 0
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#define REVERSED 1
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static int show_type = NORMAL;
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static int get_extended_sha1(char *name, unsigned char *sha1);
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/*
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* Some arguments are relevant "revision" arguments,
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* others are about output format or other details.
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* This sorts it all out.
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*/
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static int is_rev_argument(const char *arg)
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{
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static const char *rev_args[] = {
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"--max-count=",
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"--max-age=",
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"--min-age=",
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"--merge-order",
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NULL
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};
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const char **p = rev_args;
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for (;;) {
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const char *str = *p++;
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int len;
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if (!str)
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return 0;
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len = strlen(str);
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if (!strncmp(arg, str, len))
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return 1;
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}
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}
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static void show_rev(int type, const unsigned char *sha1)
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{
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if (no_revs)
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return;
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output_revs++;
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printf("%s%s\n", type == show_type ? "" : "^", sha1_to_hex(sha1));
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}
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static void show_rev_arg(char *rev)
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{
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if (no_revs)
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return;
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puts(rev);
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}
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static void show_norev(char *norev)
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{
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if (revs_only)
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return;
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puts(norev);
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}
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static void show_arg(char *arg)
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{
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if (do_rev_argument && is_rev_argument(arg))
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show_rev_arg(arg);
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else
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show_norev(arg);
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}
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static int get_parent(char *name, unsigned char *result, int idx)
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{
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unsigned char sha1[20];
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int ret = get_extended_sha1(name, sha1);
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struct commit *commit;
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struct commit_list *p;
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if (ret)
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return ret;
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commit = lookup_commit_reference(sha1);
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if (!commit)
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return -1;
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if (parse_commit(commit))
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return -1;
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p = commit->parents;
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while (p) {
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if (!--idx) {
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memcpy(result, p->item->object.sha1, 20);
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return 0;
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}
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p = p->next;
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}
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return -1;
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}
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static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
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{
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static char dirname[PATH_MAX];
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char hex[40];
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DIR *dir;
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int found;
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snprintf(dirname, sizeof(dirname), "%s/%.2s", get_object_directory(), name);
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dir = opendir(dirname);
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sprintf(hex, "%.2s", name);
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found = 0;
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if (dir) {
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struct dirent *de;
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while ((de = readdir(dir)) != NULL) {
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if (strlen(de->d_name) != 38)
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continue;
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if (memcmp(de->d_name, name + 2, len-2))
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continue;
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memcpy(hex + 2, de->d_name, 38);
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if (++found > 1)
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break;
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}
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closedir(dir);
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}
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if (found == 1)
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return get_sha1_hex(hex, sha1) == 0;
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return 0;
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}
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static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
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{
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do {
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if (*a != *b)
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return 0;
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a++;
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b++;
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len -= 2;
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} while (len > 1);
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if (len)
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if ((*a ^ *b) & 0xf0)
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return 0;
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return 1;
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}
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static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
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{
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struct packed_git *p;
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prepare_packed_git();
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for (p = packed_git; p; p = p->next) {
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unsigned num = num_packed_objects(p);
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unsigned first = 0, last = num;
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while (first < last) {
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unsigned mid = (first + last) / 2;
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unsigned char now[20];
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int cmp;
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nth_packed_object_sha1(p, mid, now);
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cmp = memcmp(match, now, 20);
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if (!cmp) {
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first = mid;
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break;
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}
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if (cmp > 0) {
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first = mid+1;
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continue;
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}
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last = mid;
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}
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if (first < num) {
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unsigned char now[20], next[20];
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nth_packed_object_sha1(p, first, now);
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if (match_sha(len, match, now)) {
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if (nth_packed_object_sha1(p, first+1, next) || !match_sha(len, match, next)) {
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memcpy(sha1, now, 20);
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return 1;
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}
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}
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}
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}
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return 0;
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}
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static int get_short_sha1(char *name, unsigned char *sha1)
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{
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int i;
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char canonical[40];
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unsigned char res[20];
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memset(res, 0, 20);
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memset(canonical, 'x', 40);
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for (i = 0;;i++) {
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unsigned char c = name[i];
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unsigned char val;
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if (!c || i > 40)
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break;
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if (c >= '0' && c <= '9')
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val = c - '0';
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else if (c >= 'a' && c <= 'f')
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val = c - 'a' + 10;
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else if (c >= 'A' && c <='F') {
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val = c - 'A' + 10;
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c -= 'A' - 'a';
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}
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else
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return -1;
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canonical[i] = c;
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if (!(i & 1))
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val <<= 4;
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res[i >> 1] |= val;
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}
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if (i < 4)
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return -1;
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if (find_short_object_filename(i, canonical, sha1))
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return 0;
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if (find_short_packed_object(i, res, sha1))
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return 0;
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return -1;
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}
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/*
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* This is like "get_sha1()", except it allows "sha1 expressions",
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* notably "xyz^" for "parent of xyz"
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*/
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static int get_extended_sha1(char *name, unsigned char *sha1)
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{
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int parent, ret;
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int len = strlen(name);
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parent = 1;
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if (len > 2 && name[len-1] >= '1' && name[len-1] <= '9') {
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parent = name[len-1] - '0';
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len--;
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}
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if (len > 1 && name[len-1] == '^') {
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name[len-1] = 0;
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ret = get_parent(name, sha1, parent);
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name[len-1] = '^';
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if (!ret)
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return 0;
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}
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ret = get_sha1(name, sha1);
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if (!ret)
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return 0;
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return get_short_sha1(name, sha1);
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}
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static void show_default(void)
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{
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char *s = def;
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if (s) {
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unsigned char sha1[20];
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def = NULL;
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if (!get_extended_sha1(s, sha1)) {
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show_rev(NORMAL, sha1);
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return;
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}
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show_arg(s);
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}
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}
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static int show_reference(const char *refname, const unsigned char *sha1)
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{
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show_rev(NORMAL, sha1);
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return 0;
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}
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int main(int argc, char **argv)
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{
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int i, as_is = 0;
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unsigned char sha1[20];
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for (i = 1; i < argc; i++) {
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char *arg = argv[i];
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char *dotdot;
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if (as_is) {
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show_norev(arg);
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continue;
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}
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if (*arg == '-') {
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if (!strcmp(arg, "--")) {
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show_default();
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if (revs_only)
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break;
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as_is = 1;
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}
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if (!strcmp(arg, "--default")) {
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def = argv[i+1];
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i++;
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continue;
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}
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if (!strcmp(arg, "--revs-only")) {
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revs_only = 1;
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continue;
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}
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if (!strcmp(arg, "--no-revs")) {
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no_revs = 1;
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continue;
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}
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if (!strcmp(arg, "--verify")) {
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revs_only = 1;
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do_rev_argument = 0;
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single_rev = 1;
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continue;
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}
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if (!strcmp(arg, "--not")) {
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show_type ^= REVERSED;
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continue;
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}
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if (!strcmp(arg, "--all")) {
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for_each_ref(show_reference);
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continue;
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}
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show_arg(arg);
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continue;
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}
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dotdot = strstr(arg, "..");
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if (dotdot) {
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unsigned char end[20];
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char *n = dotdot+2;
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*dotdot = 0;
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if (!get_extended_sha1(arg, sha1)) {
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if (!*n)
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n = "HEAD";
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if (!get_extended_sha1(n, end)) {
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if (no_revs)
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continue;
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def = NULL;
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show_rev(NORMAL, end);
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show_rev(REVERSED, sha1);
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continue;
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}
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}
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*dotdot = '.';
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}
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if (!get_extended_sha1(arg, sha1)) {
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if (no_revs)
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continue;
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def = NULL;
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show_rev(NORMAL, sha1);
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continue;
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}
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if (*arg == '^' && !get_extended_sha1(arg+1, sha1)) {
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if (no_revs)
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continue;
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def = NULL;
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show_rev(REVERSED, sha1);
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continue;
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}
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show_default();
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show_norev(arg);
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}
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show_default();
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if (single_rev && output_revs != 1) {
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fprintf(stderr, "Needed a single revision\n");
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exit(1);
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}
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return 0;
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}
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