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Update get_sha1() to grok extended format.
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Everybody envies rev-parse, who is the only one that can grok
the extended sha1 format.  Move the get_extended_sha1() out of
rev-parse, rename it to get_sha1() and make it available to
everybody else.

The one I posted earlier to the list had one bug where it did
not handle a name that ends with a digit correctly (it
incorrectly tried the "Nth parent" path).  This commit fixes it.

Signed-off-by: Junio C Hamano <junkio@cox.net>
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Junio C Hamano committed Aug 5, 2005
1 parent 37fde87 commit 9938af6
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Showing 4 changed files with 235 additions and 223 deletions.
3 changes: 2 additions & 1 deletion Makefile
View file
Original file line number Diff line number Diff line change
Expand Up @@ -95,7 +95,8 @@ LIB_H=cache.h object.h blob.h tree.h commit.h tag.h delta.h epoch.h csum-file.h
pack.h pkt-line.h refs.h
LIB_OBJS=read-cache.o sha1_file.o usage.o object.o commit.o tree.o blob.o \
tag.o date.o index.o diff-delta.o patch-delta.o entry.o path.o \
refs.o csum-file.o pack-check.o pkt-line.o connect.o ident.o
refs.o csum-file.o pack-check.o pkt-line.o connect.o ident.o \
sha1_name.o

LIB_H += rev-cache.h
LIB_OBJS += rev-cache.o
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188 changes: 5 additions & 183 deletions rev-parse.c
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Original file line number Diff line number Diff line change
Expand Up @@ -21,8 +21,6 @@ static int output_sq = 0;
#define REVERSED 1
static int show_type = NORMAL;

static int get_extended_sha1(char *name, unsigned char *sha1);

/*
* Some arguments are relevant "revision" arguments,
* others are about output format or other details.
Expand Down Expand Up @@ -107,182 +105,6 @@ static void show_arg(char *arg)
show_norev(arg);
}

static int get_parent(char *name, unsigned char *result, int idx)
{
unsigned char sha1[20];
int ret = get_extended_sha1(name, sha1);
struct commit *commit;
struct commit_list *p;

if (ret)
return ret;
commit = lookup_commit_reference(sha1);
if (!commit)
return -1;
if (parse_commit(commit))
return -1;
if (!idx) {
memcpy(result, commit->object.sha1, 20);
return 0;
}
p = commit->parents;
while (p) {
if (!--idx) {
memcpy(result, p->item->object.sha1, 20);
return 0;
}
p = p->next;
}
return -1;
}

static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
{
static char dirname[PATH_MAX];
char hex[40];
DIR *dir;
int found;

snprintf(dirname, sizeof(dirname), "%s/%.2s", get_object_directory(), name);
dir = opendir(dirname);
sprintf(hex, "%.2s", name);
found = 0;
if (dir) {
struct dirent *de;
while ((de = readdir(dir)) != NULL) {
if (strlen(de->d_name) != 38)
continue;
if (memcmp(de->d_name, name + 2, len-2))
continue;
memcpy(hex + 2, de->d_name, 38);
if (++found > 1)
break;
}
closedir(dir);
}
if (found == 1)
return get_sha1_hex(hex, sha1) == 0;
return 0;
}

static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
{
do {
if (*a != *b)
return 0;
a++;
b++;
len -= 2;
} while (len > 1);
if (len)
if ((*a ^ *b) & 0xf0)
return 0;
return 1;
}

static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
{
struct packed_git *p;

prepare_packed_git();
for (p = packed_git; p; p = p->next) {
unsigned num = num_packed_objects(p);
unsigned first = 0, last = num;
while (first < last) {
unsigned mid = (first + last) / 2;
unsigned char now[20];
int cmp;

nth_packed_object_sha1(p, mid, now);
cmp = memcmp(match, now, 20);
if (!cmp) {
first = mid;
break;
}
if (cmp > 0) {
first = mid+1;
continue;
}
last = mid;
}
if (first < num) {
unsigned char now[20], next[20];
nth_packed_object_sha1(p, first, now);
if (match_sha(len, match, now)) {
if (nth_packed_object_sha1(p, first+1, next) || !match_sha(len, match, next)) {
memcpy(sha1, now, 20);
return 1;
}
}
}
}
return 0;
}

static int get_short_sha1(char *name, unsigned char *sha1)
{
int i;
char canonical[40];
unsigned char res[20];

memset(res, 0, 20);
memset(canonical, 'x', 40);
for (i = 0;;i++) {
unsigned char c = name[i];
unsigned char val;
if (!c || i > 40)
break;
if (c >= '0' && c <= '9')
val = c - '0';
else if (c >= 'a' && c <= 'f')
val = c - 'a' + 10;
else if (c >= 'A' && c <='F') {
val = c - 'A' + 10;
c -= 'A' - 'a';
}
else
return -1;
canonical[i] = c;
if (!(i & 1))
val <<= 4;
res[i >> 1] |= val;
}
if (i < 4)
return -1;
if (find_short_object_filename(i, canonical, sha1))
return 0;
if (find_short_packed_object(i, res, sha1))
return 0;
return -1;
}

/*
* This is like "get_sha1()", except it allows "sha1 expressions",
* notably "xyz^" for "parent of xyz"
*/
static int get_extended_sha1(char *name, unsigned char *sha1)
{
int parent, ret;
int len = strlen(name);

parent = 1;
if (len > 2 && name[len-1] >= '0' && name[len-1] <= '9') {
parent = name[len-1] - '0';
len--;
}
if (len > 1 && name[len-1] == '^') {
name[len-1] = 0;
ret = get_parent(name, sha1, parent);
name[len-1] = '^';
if (!ret)
return 0;
}
ret = get_sha1(name, sha1);
if (!ret)
return 0;
return get_short_sha1(name, sha1);
}

static void show_default(void)
{
char *s = def;
Expand All @@ -291,7 +113,7 @@ static void show_default(void)
unsigned char sha1[20];

def = NULL;
if (!get_extended_sha1(s, sha1)) {
if (!get_sha1(s, sha1)) {
show_rev(NORMAL, sha1);
return;
}
Expand Down Expand Up @@ -372,10 +194,10 @@ int main(int argc, char **argv)
unsigned char end[20];
char *n = dotdot+2;
*dotdot = 0;
if (!get_extended_sha1(arg, sha1)) {
if (!get_sha1(arg, sha1)) {
if (!*n)
n = "HEAD";
if (!get_extended_sha1(n, end)) {
if (!get_sha1(n, end)) {
if (no_revs)
continue;
def = NULL;
Expand All @@ -386,14 +208,14 @@ int main(int argc, char **argv)
}
*dotdot = '.';
}
if (!get_extended_sha1(arg, sha1)) {
if (!get_sha1(arg, sha1)) {
if (no_revs)
continue;
def = NULL;
show_rev(NORMAL, sha1);
continue;
}
if (*arg == '^' && !get_extended_sha1(arg+1, sha1)) {
if (*arg == '^' && !get_sha1(arg+1, sha1)) {
if (no_revs)
continue;
def = NULL;
Expand Down
39 changes: 0 additions & 39 deletions sha1_file.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -46,21 +46,6 @@ int get_sha1_hex(const char *hex, unsigned char *sha1)
return 0;
}

static int get_sha1_file(const char *path, unsigned char *result)
{
char buffer[60];
int fd = open(path, O_RDONLY);
int len;

if (fd < 0)
return -1;
len = read(fd, buffer, sizeof(buffer));
close(fd);
if (len < 40)
return -1;
return get_sha1_hex(buffer, result);
}

static char *git_dir, *git_object_dir, *git_index_file, *git_refs_dir,
*git_graft_file;
static void setup_git_env(void)
Expand Down Expand Up @@ -132,30 +117,6 @@ int safe_create_leading_directories(char *path)
return 0;
}

int get_sha1(const char *str, unsigned char *sha1)
{
static const char *prefix[] = {
"",
"refs",
"refs/tags",
"refs/heads",
"refs/snap",
NULL
};
const char **p;

if (!get_sha1_hex(str, sha1))
return 0;

for (p = prefix; *p; p++) {
char * pathname = git_path("%s/%s", *p, str);
if (!get_sha1_file(pathname, sha1))
return 0;
}

return -1;
}

char * sha1_to_hex(const unsigned char *sha1)
{
static char buffer[50];
Expand Down
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