git/convert-cache.c
Christopher Li 812666c8e6 [PATCH] introduce xmalloc and xrealloc
Introduce xmalloc and xrealloc to die gracefully with a descriptive
message when out of memory, rather than taking a SIGSEGV. 

Signed-off-by: Christopher Li<chrislgit@chrisli.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-26 12:00:58 -07:00

313 lines
6.7 KiB
C

#define _XOPEN_SOURCE /* glibc2 needs this */
#include <time.h>
#include <ctype.h>
#include "cache.h"
struct entry {
unsigned char old_sha1[20];
unsigned char new_sha1[20];
int converted;
};
#define MAXOBJECTS (1000000)
static struct entry *convert[MAXOBJECTS];
static int nr_convert;
static struct entry * convert_entry(unsigned char *sha1);
static struct entry *insert_new(unsigned char *sha1, int pos)
{
struct entry *new = xmalloc(sizeof(struct entry));
memset(new, 0, sizeof(*new));
memcpy(new->old_sha1, sha1, 20);
memmove(convert + pos + 1, convert + pos, (nr_convert - pos) * sizeof(struct entry *));
convert[pos] = new;
nr_convert++;
if (nr_convert == MAXOBJECTS)
die("you're kidding me - hit maximum object limit");
return new;
}
static struct entry *lookup_entry(unsigned char *sha1)
{
int low = 0, high = nr_convert;
while (low < high) {
int next = (low + high) / 2;
struct entry *n = convert[next];
int cmp = memcmp(sha1, n->old_sha1, 20);
if (!cmp)
return n;
if (cmp < 0) {
high = next;
continue;
}
low = next+1;
}
return insert_new(sha1, low);
}
static void convert_binary_sha1(void *buffer)
{
struct entry *entry = convert_entry(buffer);
memcpy(buffer, entry->new_sha1, 20);
}
static void convert_ascii_sha1(void *buffer)
{
unsigned char sha1[20];
struct entry *entry;
if (get_sha1_hex(buffer, sha1))
die("bad sha1");
entry = convert_entry(sha1);
memcpy(buffer, sha1_to_hex(entry->new_sha1), 40);
}
static int write_subdirectory(void *buffer, unsigned long size, const char *base, int baselen, unsigned char *result_sha1)
{
char *new = xmalloc(size);
unsigned long newlen = 0;
unsigned long used;
used = 0;
while (size) {
int len = 21 + strlen(buffer);
char *path = strchr(buffer, ' ');
unsigned char *sha1;
unsigned int mode;
char *slash, *origpath;
if (!path || sscanf(buffer, "%o", &mode) != 1)
die("bad tree conversion");
path++;
if (memcmp(path, base, baselen))
break;
origpath = path;
path += baselen;
slash = strchr(path, '/');
if (!slash) {
newlen += sprintf(new + newlen, "%o %s", mode, path);
new[newlen++] = '\0';
memcpy(new + newlen, buffer + len - 20, 20);
newlen += 20;
used += len;
size -= len;
buffer += len;
continue;
}
newlen += sprintf(new + newlen, "%o %.*s", S_IFDIR, slash - path, path);
new[newlen++] = 0;
sha1 = (unsigned char *)(new + newlen);
newlen += 20;
len = write_subdirectory(buffer, size, origpath, slash-origpath+1, sha1);
used += len;
size -= len;
buffer += len;
}
write_sha1_file(new, newlen, "tree", result_sha1);
free(new);
return used;
}
static void convert_tree(void *buffer, unsigned long size, unsigned char *result_sha1)
{
void *orig_buffer = buffer;
unsigned long orig_size = size;
while (size) {
int len = 1+strlen(buffer);
convert_binary_sha1(buffer + len);
len += 20;
if (len > size)
die("corrupt tree object");
size -= len;
buffer += len;
}
write_subdirectory(orig_buffer, orig_size, "", 0, result_sha1);
}
static unsigned long parse_oldstyle_date(const char *buf)
{
char c, *p;
char buffer[100];
struct tm tm;
const char *formats[] = {
"%c",
"%a %b %d %T",
"%Z",
"%Y",
" %Y",
NULL
};
/* We only ever did two timezones in the bad old format .. */
const char *timezones[] = {
"PDT", "PST", "CEST", NULL
};
const char **fmt = formats;
p = buffer;
while (isspace(c = *buf))
buf++;
while ((c = *buf++) != '\n')
*p++ = c;
*p++ = 0;
buf = buffer;
memset(&tm, 0, sizeof(tm));
do {
const char *next = strptime(buf, *fmt, &tm);
if (next) {
if (!*next)
return mktime(&tm);
buf = next;
} else {
const char **p = timezones;
while (isspace(*buf))
buf++;
while (*p) {
if (!memcmp(buf, *p, strlen(*p))) {
buf += strlen(*p);
break;
}
p++;
}
}
fmt++;
} while (*buf && *fmt);
printf("left: %s\n", buf);
return mktime(&tm);
}
static int convert_date_line(char *dst, void **buf, unsigned long *sp)
{
unsigned long size = *sp;
char *line = *buf;
char *next = strchr(line, '\n');
char *date = strchr(line, '>');
int len;
if (!next || !date)
die("missing or bad author/committer line %s", line);
next++; date += 2;
*buf = next;
*sp = size - (next - line);
len = date - line;
memcpy(dst, line, len);
dst += len;
/* Is it already in new format? */
if (isdigit(*date)) {
int datelen = next - date;
memcpy(dst, date, datelen);
return len + datelen;
}
/*
* Hacky hacky: one of the sparse old-style commits does not have
* any date at all, but we can fake it by using the committer date.
*/
if (*date == '\n' && strchr(next, '>'))
date = strchr(next, '>')+2;
return len + sprintf(dst, "%lu -0700\n", parse_oldstyle_date(date));
}
static void convert_date(void *buffer, unsigned long size, unsigned char *result_sha1)
{
char *new = xmalloc(size + 100);
unsigned long newlen = 0;
// "tree <sha1>\n"
memcpy(new + newlen, buffer, 46);
newlen += 46;
buffer += 46;
size -= 46;
// "parent <sha1>\n"
while (!memcmp(buffer, "parent ", 7)) {
memcpy(new + newlen, buffer, 48);
newlen += 48;
buffer += 48;
size -= 48;
}
// "author xyz <xyz> date"
newlen += convert_date_line(new + newlen, &buffer, &size);
// "committer xyz <xyz> date"
newlen += convert_date_line(new + newlen, &buffer, &size);
// Rest
memcpy(new + newlen, buffer, size);
newlen += size;
write_sha1_file(new, newlen, "commit", result_sha1);
free(new);
}
static void convert_commit(void *buffer, unsigned long size, unsigned char *result_sha1)
{
void *orig_buffer = buffer;
unsigned long orig_size = size;
convert_ascii_sha1(buffer+5);
buffer += 46; /* "tree " + "hex sha1" + "\n" */
while (!memcmp(buffer, "parent ", 7)) {
convert_ascii_sha1(buffer+7);
buffer += 48;
}
convert_date(orig_buffer, orig_size, result_sha1);
}
static struct entry * convert_entry(unsigned char *sha1)
{
struct entry *entry = lookup_entry(sha1);
char type[20];
void *buffer, *data;
unsigned long size;
if (entry->converted)
return entry;
data = read_sha1_file(sha1, type, &size);
if (!data)
die("unable to read object %s", sha1_to_hex(sha1));
buffer = xmalloc(size);
memcpy(buffer, data, size);
if (!strcmp(type, "blob")) {
write_sha1_file(buffer, size, "blob", entry->new_sha1);
} else if (!strcmp(type, "tree"))
convert_tree(buffer, size, entry->new_sha1);
else if (!strcmp(type, "commit"))
convert_commit(buffer, size, entry->new_sha1);
else
die("unknown object type '%s' in %s", type, sha1_to_hex(sha1));
entry->converted = 1;
free(buffer);
return entry;
}
int main(int argc, char **argv)
{
unsigned char sha1[20];
struct entry *entry;
if (argc != 2 || get_sha1_hex(argv[1], sha1))
usage("convert-cache <sha1>");
entry = convert_entry(sha1);
printf("new sha1: %s\n", sha1_to_hex(entry->new_sha1));
return 0;
}