1dfcfbce2d
I think Linus did a cut & paste from an early JIT code while developing the current extended SHA1 notation, and left it there as a courtesy, but the directory does not deserve to be treated any more specially than, say, .git/refs/bisect. If the subdirectories under .git/refs proliferate, we may want to switch to scanning that hierarchy at runtime, instead of the current hard-coded set, although I think that would be overkill. Signed-off-by: Junio C Hamano <junkio@cox.net> From nobody Mon Sep 17 00:00:00 2001 Subject: [PATCH] Add a new extended SHA1 syntax <name>:<num> From: Junio C Hamano <junkio@cox.net> Date: 1124617434 -0700 The new notation is a short-hand for <name> followed by <num> caret ('^') characters. E.g. "master:4" is the fourth generation ancestor of the current "master" branch head, following the first parents; same as "master^^^^" but a bit more readable. This will be used in the updated "git show-branch" command. Signed-off-by: Junio C Hamano <junkio@cox.net> --- sha1_name.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 files changed, 41 insertions(+), 0 deletions(-) d5098ce769da46df6d45dc8f41b06dd758fdaea7 diff --git a/sha1_name.c b/sha1_name.c --- a/sha1_name.c +++ b/sha1_name.c @@ -191,9 +191,29 @@ static int get_parent(const char *name, return -1; } +static int get_nth_ancestor(const char *name, int len, + unsigned char *result, int generation) +{ + unsigned char sha1[20]; + int ret = get_sha1_1(name, len, sha1); + if (ret) + return ret; + + while (generation--) { + struct commit *commit = lookup_commit_reference(sha1); + + if (!commit || parse_commit(commit) || !commit->parents) + return -1; + memcpy(sha1, commit->parents->item->object.sha1, 20); + } + memcpy(result, sha1, 20); + return 0; +} + static int get_sha1_1(const char *name, int len, unsigned char *sha1) { int parent, ret; + const char *cp; /* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */ if (len > 2 && name[len-2] == '^' && @@ -210,6 +230,27 @@ static int get_sha1_1(const char *name, if (parent >= 0) return get_parent(name, len, sha1, parent); + /* name:3 is name^^^, + * name:12 is name^^^^^^^^^^^^, and + * name: is name + */ + parent = 0; + for (cp = name + len - 1; name <= cp; cp--) { + int ch = *cp; + if ('0' <= ch && ch <= '9') + continue; + if (ch != ':') + parent = -1; + break; + } + if (!parent && *cp == ':') { + int len1 = cp - name; + cp++; + while (cp < name + len) + parent = parent * 10 + *cp++ - '0'; + return get_nth_ancestor(name, len1, sha1, parent); + } + ret = get_sha1_basic(name, len, sha1); if (!ret) return 0;
227 lines
4.4 KiB
C
227 lines
4.4 KiB
C
#include "cache.h"
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#include "commit.h"
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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(const 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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static int get_sha1_file(const char *path, unsigned char *result)
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{
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char buffer[60];
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int fd = open(path, O_RDONLY);
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int len;
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if (fd < 0)
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return -1;
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len = read(fd, buffer, sizeof(buffer));
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close(fd);
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if (len < 40)
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return -1;
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return get_sha1_hex(buffer, result);
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}
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static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
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{
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static const char *prefix[] = {
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"",
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"refs",
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"refs/tags",
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"refs/heads",
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NULL
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};
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const char **p;
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if (len == 40 && !get_sha1_hex(str, sha1))
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return 0;
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for (p = prefix; *p; p++) {
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char *pathname = git_path("%s/%.*s", *p, len, str);
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if (!get_sha1_file(pathname, sha1))
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return 0;
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}
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return -1;
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}
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static int get_sha1_1(const char *name, int len, unsigned char *sha1);
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static int get_parent(const char *name, int len,
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unsigned char *result, int idx)
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{
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unsigned char sha1[20];
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int ret = get_sha1_1(name, len, 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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if (!idx) {
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memcpy(result, commit->object.sha1, 20);
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return 0;
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}
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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 get_sha1_1(const char *name, int len, unsigned char *sha1)
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{
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int parent, ret;
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/* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */
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if (len > 2 && name[len-2] == '^' &&
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name[len-1] >= '0' && name[len-1] <= '9') {
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parent = name[len-1] - '0';
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len -= 2;
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}
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else if (len > 1 && name[len-1] == '^') {
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parent = 1;
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len--;
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} else
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parent = -1;
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if (parent >= 0)
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return get_parent(name, len, sha1, parent);
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ret = get_sha1_basic(name, len, 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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/*
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* This is like "get_sha1_basic()", except it allows "sha1 expressions",
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* notably "xyz^" for "parent of xyz"
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*/
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int get_sha1(const char *name, unsigned char *sha1)
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{
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return get_sha1_1(name, strlen(name), sha1);
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}
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