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git/config.c
Linus Torvalds 93821bd97a sha1_file: add the ability to parse objects in "pack file format" 
The pack-file format is slightly different from the traditional git
object format, in that it has a much denser binary header encoding.
The traditional format uses an ASCII string with type and length
information, which is somewhat wasteful.

A new object format starts with uncompressed binary header
followed by compressed payload -- this will allow us later to
copy the payload straight to packfiles.

Obviously they cannot be read by older versions of git, so for
now new object files are created with the traditional format.
core.legacyheaders configuration item, when set to false makes
the code write in new format for people to experiment with.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-07-13 23:11:56 -07:00

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/*
* GIT - The information manager from hell
*
* Copyright (C) Linus Torvalds, 2005
* Copyright (C) Johannes Schindelin, 2005
*
*/
#include "cache.h"
#include <regex.h>
#define MAXNAME (256)
static FILE *config_file;
static const char *config_file_name;
static int config_linenr;
static int get_next_char(void)
{
int c;
FILE *f;
c = '\n';
if ((f = config_file) != NULL) {
c = fgetc(f);
if (c == '\r') {
/* DOS like systems */
c = fgetc(f);
if (c != '\n') {
ungetc(c, f);
c = '\r';
}
}
if (c == '\n')
config_linenr++;
if (c == EOF) {
config_file = NULL;
c = '\n';
}
}
return c;
}
static char *parse_value(void)
{
static char value[1024];
int quote = 0, comment = 0, len = 0, space = 0;
for (;;) {
int c = get_next_char();
if (len >= sizeof(value))
return NULL;
if (c == '\n') {
if (quote)
return NULL;
value[len] = 0;
return value;
}
if (comment)
continue;
if (isspace(c) && !quote) {
space = 1;
continue;
}
if (!quote) {
if (c == ';' || c == '#') {
comment = 1;
continue;
}
}
if (space) {
if (len)
value[len++] = ' ';
space = 0;
}
if (c == '\\') {
c = get_next_char();
switch (c) {
case '\n':
continue;
case 't':
c = '\t';
break;
case 'b':
c = '\b';
break;
case 'n':
c = '\n';
break;
/* Some characters escape as themselves */
case '\\': case '"':
break;
/* Reject unknown escape sequences */
default:
return NULL;
}
value[len++] = c;
continue;
}
if (c == '"') {
quote = 1-quote;
continue;
}
value[len++] = c;
}
}
static int get_value(config_fn_t fn, char *name, unsigned int len)
{
int c;
char *value;
/* Get the full name */
for (;;) {
c = get_next_char();
if (c == EOF)
break;
if (!isalnum(c))
break;
name[len++] = tolower(c);
if (len >= MAXNAME)
return -1;
}
name[len] = 0;
while (c == ' ' || c == '\t')
c = get_next_char();
value = NULL;
if (c != '\n') {
if (c != '=')
return -1;
value = parse_value();
if (!value)
return -1;
}
return fn(name, value);
}
static int get_extended_base_var(char *name, int baselen, int c)
{
do {
if (c == '\n')
return -1;
c = get_next_char();
} while (isspace(c));
/* We require the format to be '[base "extension"]' */
if (c != '"')
return -1;
name[baselen++] = '.';
for (;;) {
int c = get_next_char();
if (c == '\n')
return -1;
if (c == '"')
break;
if (c == '\\') {
c = get_next_char();
if (c == '\n')
return -1;
}
name[baselen++] = c;
if (baselen > MAXNAME / 2)
return -1;
}
/* Final ']' */
if (get_next_char() != ']')
return -1;
return baselen;
}
static int get_base_var(char *name)
{
int baselen = 0;
for (;;) {
int c = get_next_char();
if (c == EOF)
return -1;
if (c == ']')
return baselen;
if (isspace(c))
return get_extended_base_var(name, baselen, c);
if (!isalnum(c) && c != '.')
return -1;
if (baselen > MAXNAME / 2)
return -1;
name[baselen++] = tolower(c);
}
}
static int git_parse_file(config_fn_t fn)
{
int comment = 0;
int baselen = 0;
static char var[MAXNAME];
for (;;) {
int c = get_next_char();
if (c == '\n') {
/* EOF? */
if (!config_file)
return 0;
comment = 0;
continue;
}
if (comment || isspace(c))
continue;
if (c == '#' || c == ';') {
comment = 1;
continue;
}
if (c == '[') {
baselen = get_base_var(var);
if (baselen <= 0)
break;
var[baselen++] = '.';
var[baselen] = 0;
continue;
}
if (!isalpha(c))
break;
var[baselen] = tolower(c);
if (get_value(fn, var, baselen+1) < 0)
break;
}
die("bad config file line %d in %s", config_linenr, config_file_name);
}
int git_config_int(const char *name, const char *value)
{
if (value && *value) {
char *end;
int val = strtol(value, &end, 0);
if (!*end)
return val;
}
die("bad config value for '%s' in %s", name, config_file_name);
}
int git_config_bool(const char *name, const char *value)
{
if (!value)
return 1;
if (!*value)
return 0;
if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
return 1;
if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
return 0;
return git_config_int(name, value) != 0;
}
int git_default_config(const char *var, const char *value)
{
/* This needs a better name */
if (!strcmp(var, "core.filemode")) {
trust_executable_bit = git_config_bool(var, value);
return 0;
}
if (!strcmp(var, "core.ignorestat")) {
assume_unchanged = git_config_bool(var, value);
return 0;
}
if (!strcmp(var, "core.prefersymlinkrefs")) {
prefer_symlink_refs = git_config_bool(var, value);
return 0;
}
if (!strcmp(var, "core.logallrefupdates")) {
log_all_ref_updates = git_config_bool(var, value);
return 0;
}
if (!strcmp(var, "core.warnambiguousrefs")) {
warn_ambiguous_refs = git_config_bool(var, value);
return 0;
}
if (!strcmp(var, "core.legacyheaders")) {
use_legacy_headers = git_config_bool(var, value);
return 0;
}
if (!strcmp(var, "core.compression")) {
int level = git_config_int(var, value);
if (level == -1)
level = Z_DEFAULT_COMPRESSION;
else if (level < 0 || level > Z_BEST_COMPRESSION)
die("bad zlib compression level %d", level);
zlib_compression_level = level;
return 0;
}
if (!strcmp(var, "user.name")) {
strlcpy(git_default_name, value, sizeof(git_default_name));
return 0;
}
if (!strcmp(var, "user.email")) {
strlcpy(git_default_email, value, sizeof(git_default_email));
return 0;
}
if (!strcmp(var, "i18n.commitencoding")) {
strlcpy(git_commit_encoding, value, sizeof(git_commit_encoding));
return 0;
}
/* Add other config variables here and to Documentation/config.txt. */
return 0;
}
int git_config_from_file(config_fn_t fn, const char *filename)
{
int ret;
FILE *f = fopen(filename, "r");
ret = -1;
if (f) {
config_file = f;
config_file_name = filename;
config_linenr = 1;
ret = git_parse_file(fn);
fclose(f);
config_file_name = NULL;
}
return ret;
}
int git_config(config_fn_t fn)
{
int ret = 0;
char *repo_config = NULL;
const char *home = NULL, *filename;
/* $GIT_CONFIG makes git read _only_ the given config file,
* $GIT_CONFIG_LOCAL will make it process it in addition to the
* global config file, the same way it would the per-repository
* config file otherwise. */
filename = getenv("GIT_CONFIG");
if (!filename) {
home = getenv("HOME");
filename = getenv("GIT_CONFIG_LOCAL");
if (!filename)
filename = repo_config = strdup(git_path("config"));
}
if (home) {
char *user_config = strdup(mkpath("%s/.gitconfig", home));
if (!access(user_config, R_OK))
ret = git_config_from_file(fn, user_config);
free(user_config);
}
ret += git_config_from_file(fn, filename);
if (repo_config)
free(repo_config);
return ret;
}
/*
* Find all the stuff for git_config_set() below.
*/
#define MAX_MATCHES 512
static struct {
int baselen;
char* key;
int do_not_match;
regex_t* value_regex;
int multi_replace;
off_t offset[MAX_MATCHES];
enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
int seen;
} store;
static int matches(const char* key, const char* value)
{
return !strcmp(key, store.key) &&
(store.value_regex == NULL ||
(store.do_not_match ^
!regexec(store.value_regex, value, 0, NULL, 0)));
}
static int store_aux(const char* key, const char* value)
{
switch (store.state) {
case KEY_SEEN:
if (matches(key, value)) {
if (store.seen == 1 && store.multi_replace == 0) {
fprintf(stderr,
"Warning: %s has multiple values\n",
key);
} else if (store.seen >= MAX_MATCHES) {
fprintf(stderr, "Too many matches\n");
return 1;
}
store.offset[store.seen] = ftell(config_file);
store.seen++;
}
break;
case SECTION_SEEN:
if (strncmp(key, store.key, store.baselen+1)) {
store.state = SECTION_END_SEEN;
break;
} else
/* do not increment matches: this is no match */
store.offset[store.seen] = ftell(config_file);
/* fallthru */
case SECTION_END_SEEN:
case START:
if (matches(key, value)) {
store.offset[store.seen] = ftell(config_file);
store.state = KEY_SEEN;
store.seen++;
} else {
if (strrchr(key, '.') - key == store.baselen &&
!strncmp(key, store.key, store.baselen)) {
store.state = SECTION_SEEN;
store.offset[store.seen] = ftell(config_file);
}
}
}
return 0;
}
static void store_write_section(int fd, const char* key)
{
const char *dot = strchr(key, '.');
int len1 = store.baselen, len2 = -1;
dot = strchr(key, '.');
if (dot) {
int dotlen = dot - key;
if (dotlen < len1) {
len2 = len1 - dotlen - 1;
len1 = dotlen;
}
}
write(fd, "[", 1);
write(fd, key, len1);
if (len2 >= 0) {
write(fd, " \"", 2);
while (--len2 >= 0) {
unsigned char c = *++dot;
if (c == '"')
write(fd, "\\", 1);
write(fd, &c, 1);
}
write(fd, "\"", 1);
}
write(fd, "]\n", 2);
}
static void store_write_pair(int fd, const char* key, const char* value)
{
int i;
write(fd, "\t", 1);
write(fd, key+store.baselen+1,
strlen(key+store.baselen+1));
write(fd, " = ", 3);
for (i = 0; value[i]; i++)
switch (value[i]) {
case '\n': write(fd, "\\n", 2); break;
case '\t': write(fd, "\\t", 2); break;
case '"': case '\\': write(fd, "\\", 1);
default: write(fd, value+i, 1);
}
write(fd, "\n", 1);
}
static int find_beginning_of_line(const char* contents, int size,
int offset_, int* found_bracket)
{
int equal_offset = size, bracket_offset = size;
int offset;
for (offset = offset_-2; offset > 0
&& contents[offset] != '\n'; offset--)
switch (contents[offset]) {
case '=': equal_offset = offset; break;
case ']': bracket_offset = offset; break;
}
if (bracket_offset < equal_offset) {
*found_bracket = 1;
offset = bracket_offset+1;
} else
offset++;
return offset;
}
int git_config_set(const char* key, const char* value)
{
return git_config_set_multivar(key, value, NULL, 0);
}
/*
* If value==NULL, unset in (remove from) config,
* if value_regex!=NULL, disregard key/value pairs where value does not match.
* if multi_replace==0, nothing, or only one matching key/value is replaced,
* else all matching key/values (regardless how many) are removed,
* before the new pair is written.
*
* Returns 0 on success.
*
* This function does this:
*
* - it locks the config file by creating ".git/config.lock"
*
* - it then parses the config using store_aux() as validator to find
* the position on the key/value pair to replace. If it is to be unset,
* it must be found exactly once.
*
* - the config file is mmap()ed and the part before the match (if any) is
* written to the lock file, then the changed part and the rest.
*
* - the config file is removed and the lock file rename()d to it.
*
*/
int git_config_set_multivar(const char* key, const char* value,
const char* value_regex, int multi_replace)
{
int i, dot;
int fd = -1, in_fd;
int ret;
char* config_filename;
char* lock_file;
const char* last_dot = strrchr(key, '.');
config_filename = getenv("GIT_CONFIG");
if (!config_filename) {
config_filename = getenv("GIT_CONFIG_LOCAL");
if (!config_filename)
config_filename = git_path("config");
}
config_filename = strdup(config_filename);
lock_file = strdup(mkpath("%s.lock", config_filename));
/*
* Since "key" actually contains the section name and the real
* key name separated by a dot, we have to know where the dot is.
*/
if (last_dot == NULL) {
fprintf(stderr, "key does not contain a section: %s\n", key);
ret = 2;
goto out_free;
}
store.baselen = last_dot - key;
store.multi_replace = multi_replace;
/*
* Validate the key and while at it, lower case it for matching.
*/
store.key = (char*)malloc(strlen(key)+1);
dot = 0;
for (i = 0; key[i]; i++) {
unsigned char c = key[i];
if (c == '.')
dot = 1;
/* Leave the extended basename untouched.. */
if (!dot || i > store.baselen) {
if (!isalnum(c) || (i == store.baselen+1 && !isalpha(c))) {
fprintf(stderr, "invalid key: %s\n", key);
free(store.key);
ret = 1;
goto out_free;
}
c = tolower(c);
}
store.key[i] = c;
}
store.key[i] = 0;
/*
* The lock_file serves a purpose in addition to locking: the new
* contents of .git/config will be written into it.
*/
fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
if (fd < 0 || adjust_shared_perm(lock_file)) {
fprintf(stderr, "could not lock config file\n");
free(store.key);
ret = -1;
goto out_free;
}
/*
* If .git/config does not exist yet, write a minimal version.
*/
in_fd = open(config_filename, O_RDONLY);
if ( in_fd < 0 ) {
free(store.key);
if ( ENOENT != errno ) {
error("opening %s: %s", config_filename,
strerror(errno));
ret = 3; /* same as "invalid config file" */
goto out_free;
}
/* if nothing to unset, error out */
if (value == NULL) {
ret = 5;
goto out_free;
}
store.key = (char*)key;
store_write_section(fd, key);
store_write_pair(fd, key, value);
} else{
struct stat st;
char* contents;
int i, copy_begin, copy_end, new_line = 0;
if (value_regex == NULL)
store.value_regex = NULL;
else {
if (value_regex[0] == '!') {
store.do_not_match = 1;
value_regex++;
} else
store.do_not_match = 0;
store.value_regex = (regex_t*)malloc(sizeof(regex_t));
if (regcomp(store.value_regex, value_regex,
REG_EXTENDED)) {
fprintf(stderr, "Invalid pattern: %s\n",
value_regex);
free(store.value_regex);
ret = 6;
goto out_free;
}
}
store.offset[0] = 0;
store.state = START;
store.seen = 0;
/*
* After this, store.offset will contain the *end* offset
* of the last match, or remain at 0 if no match was found.
* As a side effect, we make sure to transform only a valid
* existing config file.
*/
if (git_config_from_file(store_aux, config_filename)) {
fprintf(stderr, "invalid config file\n");
free(store.key);
if (store.value_regex != NULL) {
regfree(store.value_regex);
free(store.value_regex);
}
ret = 3;
goto out_free;
}
free(store.key);
if (store.value_regex != NULL) {
regfree(store.value_regex);
free(store.value_regex);
}
/* if nothing to unset, or too many matches, error out */
if ((store.seen == 0 && value == NULL) ||
(store.seen > 1 && multi_replace == 0)) {
ret = 5;
goto out_free;
}
fstat(in_fd, &st);
contents = mmap(NULL, st.st_size, PROT_READ,
MAP_PRIVATE, in_fd, 0);
close(in_fd);
if (store.seen == 0)
store.seen = 1;
for (i = 0, copy_begin = 0; i < store.seen; i++) {
if (store.offset[i] == 0) {
store.offset[i] = copy_end = st.st_size;
} else if (store.state != KEY_SEEN) {
copy_end = store.offset[i];
} else
copy_end = find_beginning_of_line(
contents, st.st_size,
store.offset[i]-2, &new_line);
/* write the first part of the config */
if (copy_end > copy_begin) {
write(fd, contents + copy_begin,
copy_end - copy_begin);
if (new_line)
write(fd, "\n", 1);
}
copy_begin = store.offset[i];
}
/* write the pair (value == NULL means unset) */
if (value != NULL) {
if (store.state == START)
store_write_section(fd, key);
store_write_pair(fd, key, value);
}
/* write the rest of the config */
if (copy_begin < st.st_size)
write(fd, contents + copy_begin,
st.st_size - copy_begin);
munmap(contents, st.st_size);
unlink(config_filename);
}
if (rename(lock_file, config_filename) < 0) {
fprintf(stderr, "Could not rename the lock file?\n");
ret = 4;
goto out_free;
}
ret = 0;
out_free:
if (0 <= fd)
close(fd);
if (config_filename)
free(config_filename);
if (lock_file) {
unlink(lock_file);
free(lock_file);
}
return ret;
}
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