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![Junio C Hamano](/assets/img/avatar_default.png)
This adds "assume unchanged" logic, started by this message in the list discussion recently: <Pine.LNX.4.64.0601311807470.7301@g5.osdl.org> This is a workaround for filesystems that do not have lstat() that is quick enough for the index mechanism to take advantage of. On the paths marked as "assumed to be unchanged", the user needs to explicitly use update-index to register the object name to be in the next commit. You can use two new options to update-index to set and reset the CE_VALID bit: git-update-index --assume-unchanged path... git-update-index --no-assume-unchanged path... These forms manipulate only the CE_VALID bit; it does not change the object name recorded in the index file. Nor they add a new entry to the index. When the configuration variable "core.ignorestat = true" is set, the index entries are marked with CE_VALID bit automatically after: - update-index to explicitly register the current object name to the index file. - when update-index --refresh finds the path to be up-to-date. - when tools like read-tree -u and apply --index update the working tree file and register the current object name to the index file. The flag is dropped upon read-tree that does not check out the index entry. This happens regardless of the core.ignorestat settings. Index entries marked with CE_VALID bit are assumed to be unchanged most of the time. However, there are cases that CE_VALID bit is ignored for the sake of safety and usability: - while "git-read-tree -m" or git-apply need to make sure that the paths involved in the merge do not have local modifications. This sacrifices performance for safety. - when git-checkout-index -f -q -u -a tries to see if it needs to checkout the paths. Otherwise you can never check anything out ;-). - when git-update-index --really-refresh (a new flag) tries to see if the index entry is up to date. You can start with everything marked as CE_VALID and run this once to drop CE_VALID bit for paths that are modified. Most notably, "update-index --refresh" honours CE_VALID and does not actively stat, so after you modified a file in the working tree, update-index --refresh would not notice until you tell the index about it with "git-update-index path" or "git-update-index --no-assume-unchanged path". This version is not expected to be perfect. I think diff between index and/or tree and working files may need some adjustment, and there probably needs other cases we should automatically unmark paths that are marked to be CE_VALID. But the basics seem to work, and ready to be tested by people who asked for this feature. Signed-off-by: Junio C Hamano <junkio@cox.net>
598 lines
12 KiB
C
598 lines
12 KiB
C
/*
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* GIT - The information manager from hell
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*
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* Copyright (C) Linus Torvalds, 2005
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* Copyright (C) Johannes Schindelin, 2005
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*
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*/
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#include "cache.h"
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#include <regex.h>
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#define MAXNAME (256)
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static FILE *config_file;
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static const char *config_file_name;
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static int config_linenr;
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static int get_next_char(void)
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{
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int c;
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FILE *f;
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c = '\n';
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if ((f = config_file) != NULL) {
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c = fgetc(f);
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if (c == '\r') {
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/* DOS like systems */
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c = fgetc(f);
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if (c != '\n') {
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ungetc(c, f);
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c = '\r';
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}
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}
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if (c == '\n')
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config_linenr++;
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if (c == EOF) {
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config_file = NULL;
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c = '\n';
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}
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}
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return c;
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}
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static char *parse_value(void)
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{
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static char value[1024];
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int quote = 0, comment = 0, len = 0, space = 0;
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for (;;) {
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int c = get_next_char();
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if (len >= sizeof(value))
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return NULL;
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if (c == '\n') {
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if (quote)
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return NULL;
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value[len] = 0;
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return value;
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}
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if (comment)
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continue;
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if (isspace(c) && !quote) {
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space = 1;
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continue;
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}
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if (space) {
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if (len)
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value[len++] = ' ';
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space = 0;
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}
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if (c == '\\') {
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c = get_next_char();
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switch (c) {
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case '\n':
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continue;
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case 't':
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c = '\t';
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break;
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case 'b':
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c = '\b';
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break;
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case 'n':
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c = '\n';
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break;
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/* Some characters escape as themselves */
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case '\\': case '"':
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break;
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/* Reject unknown escape sequences */
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default:
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return NULL;
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}
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value[len++] = c;
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continue;
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}
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if (c == '"') {
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quote = 1-quote;
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continue;
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}
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if (!quote) {
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if (c == ';' || c == '#') {
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comment = 1;
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continue;
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}
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}
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value[len++] = c;
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}
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}
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static int get_value(config_fn_t fn, char *name, unsigned int len)
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{
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int c;
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char *value;
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/* Get the full name */
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for (;;) {
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c = get_next_char();
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if (c == EOF)
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break;
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if (!isalnum(c))
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break;
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name[len++] = tolower(c);
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if (len >= MAXNAME)
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return -1;
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}
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name[len] = 0;
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while (c == ' ' || c == '\t')
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c = get_next_char();
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value = NULL;
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if (c != '\n') {
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if (c != '=')
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return -1;
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value = parse_value();
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if (!value)
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return -1;
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}
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return fn(name, value);
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}
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static int get_base_var(char *name)
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{
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int baselen = 0;
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for (;;) {
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int c = get_next_char();
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if (c == EOF)
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return -1;
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if (c == ']')
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return baselen;
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if (!isalnum(c) && c != '.')
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return -1;
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if (baselen > MAXNAME / 2)
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return -1;
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name[baselen++] = tolower(c);
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}
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}
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static int git_parse_file(config_fn_t fn)
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{
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int comment = 0;
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int baselen = 0;
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static char var[MAXNAME];
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for (;;) {
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int c = get_next_char();
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if (c == '\n') {
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/* EOF? */
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if (!config_file)
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return 0;
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comment = 0;
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continue;
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}
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if (comment || isspace(c))
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continue;
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if (c == '#' || c == ';') {
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comment = 1;
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continue;
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}
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if (c == '[') {
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baselen = get_base_var(var);
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if (baselen <= 0)
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break;
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var[baselen++] = '.';
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var[baselen] = 0;
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continue;
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}
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if (!isalpha(c))
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break;
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var[baselen] = tolower(c);
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if (get_value(fn, var, baselen+1) < 0)
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break;
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}
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die("bad config file line %d in %s", config_linenr, config_file_name);
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}
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int git_config_int(const char *name, const char *value)
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{
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if (value && *value) {
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char *end;
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int val = strtol(value, &end, 0);
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if (!*end)
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return val;
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}
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die("bad config value for '%s' in %s", name, config_file_name);
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}
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int git_config_bool(const char *name, const char *value)
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{
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if (!value)
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return 1;
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if (!*value)
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return 0;
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if (!strcasecmp(value, "true"))
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return 1;
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if (!strcasecmp(value, "false"))
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return 0;
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return git_config_int(name, value) != 0;
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}
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int git_default_config(const char *var, const char *value)
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{
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/* This needs a better name */
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if (!strcmp(var, "core.filemode")) {
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trust_executable_bit = git_config_bool(var, value);
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return 0;
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}
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if (!strcmp(var, "core.ignorestat")) {
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assume_unchanged = git_config_bool(var, value);
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return 0;
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}
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if (!strcmp(var, "core.symrefsonly")) {
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only_use_symrefs = git_config_bool(var, value);
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return 0;
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}
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if (!strcmp(var, "user.name")) {
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strncpy(git_default_name, value, sizeof(git_default_name));
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return 0;
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}
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if (!strcmp(var, "user.email")) {
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strncpy(git_default_email, value, sizeof(git_default_email));
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return 0;
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}
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if (!strcmp(var, "i18n.commitencoding")) {
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strncpy(git_commit_encoding, value, sizeof(git_commit_encoding));
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return 0;
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}
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/* Add other config variables here.. */
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return 0;
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}
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int git_config_from_file(config_fn_t fn, const char *filename)
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{
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int ret;
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FILE *f = fopen(filename, "r");
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ret = -1;
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if (f) {
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config_file = f;
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config_file_name = filename;
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config_linenr = 1;
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ret = git_parse_file(fn);
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fclose(f);
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config_file_name = NULL;
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}
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return ret;
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}
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int git_config(config_fn_t fn)
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{
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return git_config_from_file(fn, git_path("config"));
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}
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/*
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* Find all the stuff for git_config_set() below.
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*/
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#define MAX_MATCHES 512
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static struct {
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int baselen;
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char* key;
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int do_not_match;
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regex_t* value_regex;
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int multi_replace;
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off_t offset[MAX_MATCHES];
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enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
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int seen;
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} store;
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static int matches(const char* key, const char* value)
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{
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return !strcmp(key, store.key) &&
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(store.value_regex == NULL ||
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(store.do_not_match ^
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!regexec(store.value_regex, value, 0, NULL, 0)));
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}
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static int store_aux(const char* key, const char* value)
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{
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switch (store.state) {
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case KEY_SEEN:
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if (matches(key, value)) {
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if (store.seen == 1 && store.multi_replace == 0) {
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fprintf(stderr,
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"Warning: %s has multiple values\n",
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key);
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} else if (store.seen >= MAX_MATCHES) {
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fprintf(stderr, "Too many matches\n");
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return 1;
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}
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store.offset[store.seen] = ftell(config_file);
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store.seen++;
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}
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break;
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case SECTION_SEEN:
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if (strncmp(key, store.key, store.baselen+1)) {
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store.state = SECTION_END_SEEN;
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break;
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} else
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/* do not increment matches: this is no match */
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store.offset[store.seen] = ftell(config_file);
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/* fallthru */
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case SECTION_END_SEEN:
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case START:
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if (matches(key, value)) {
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store.offset[store.seen] = ftell(config_file);
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store.state = KEY_SEEN;
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store.seen++;
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} else if(!strncmp(key, store.key, store.baselen))
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store.state = SECTION_SEEN;
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}
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return 0;
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}
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static void store_write_section(int fd, const char* key)
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{
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write(fd, "[", 1);
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write(fd, key, store.baselen);
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write(fd, "]\n", 2);
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}
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static void store_write_pair(int fd, const char* key, const char* value)
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{
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int i;
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write(fd, "\t", 1);
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write(fd, key+store.baselen+1,
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strlen(key+store.baselen+1));
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write(fd, " = ", 3);
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for (i = 0; value[i]; i++)
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switch (value[i]) {
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case '\n': write(fd, "\\n", 2); break;
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case '\t': write(fd, "\\t", 2); break;
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case '"': case '\\': write(fd, "\\", 1);
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default: write(fd, value+i, 1);
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}
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write(fd, "\n", 1);
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}
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static int find_beginning_of_line(const char* contents, int size,
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int offset_, int* found_bracket)
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{
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int equal_offset = size, bracket_offset = size;
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int offset;
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for (offset = offset_-2; offset > 0
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&& contents[offset] != '\n'; offset--)
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switch (contents[offset]) {
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case '=': equal_offset = offset; break;
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case ']': bracket_offset = offset; break;
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}
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if (bracket_offset < equal_offset) {
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*found_bracket = 1;
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offset = bracket_offset+1;
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} else
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offset++;
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return offset;
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}
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int git_config_set(const char* key, const char* value)
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{
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return git_config_set_multivar(key, value, NULL, 0);
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}
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/*
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* If value==NULL, unset in (remove from) config,
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* if value_regex!=NULL, disregard key/value pairs where value does not match.
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* if multi_replace==0, nothing, or only one matching key/value is replaced,
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* else all matching key/values (regardless how many) are removed,
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* before the new pair is written.
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*
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* Returns 0 on success.
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*
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* This function does this:
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*
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* - it locks the config file by creating ".git/config.lock"
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*
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* - it then parses the config using store_aux() as validator to find
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* the position on the key/value pair to replace. If it is to be unset,
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* it must be found exactly once.
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*
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* - the config file is mmap()ed and the part before the match (if any) is
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* written to the lock file, then the changed part and the rest.
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*
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* - the config file is removed and the lock file rename()d to it.
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*
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*/
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int git_config_set_multivar(const char* key, const char* value,
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const char* value_regex, int multi_replace)
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{
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int i;
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int fd, in_fd;
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char* config_filename = strdup(git_path("config"));
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char* lock_file = strdup(git_path("config.lock"));
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const char* last_dot = strrchr(key, '.');
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/*
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* Since "key" actually contains the section name and the real
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* key name separated by a dot, we have to know where the dot is.
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*/
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if (last_dot == NULL) {
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fprintf(stderr, "key does not contain a section: %s\n", key);
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return 2;
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}
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store.baselen = last_dot - key;
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store.multi_replace = multi_replace;
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/*
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* Validate the key and while at it, lower case it for matching.
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*/
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store.key = (char*)malloc(strlen(key)+1);
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for (i = 0; key[i]; i++)
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if (i != store.baselen &&
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((!isalnum(key[i]) && key[i] != '.') ||
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(i == store.baselen+1 && !isalpha(key[i])))) {
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fprintf(stderr, "invalid key: %s\n", key);
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free(store.key);
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return 1;
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} else
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store.key[i] = tolower(key[i]);
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store.key[i] = 0;
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/*
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* The lock_file serves a purpose in addition to locking: the new
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* contents of .git/config will be written into it.
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*/
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fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
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if (fd < 0) {
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fprintf(stderr, "could not lock config file\n");
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free(store.key);
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return -1;
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}
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/*
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* If .git/config does not exist yet, write a minimal version.
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*/
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in_fd = open(config_filename, O_RDONLY);
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if ( in_fd < 0 ) {
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free(store.key);
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if ( ENOENT != errno ) {
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error("opening %s: %s", config_filename,
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strerror(errno));
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close(fd);
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unlink(lock_file);
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return 3; /* same as "invalid config file" */
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}
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/* if nothing to unset, error out */
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if (value == NULL) {
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close(fd);
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unlink(lock_file);
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return 5;
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}
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store.key = (char*)key;
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store_write_section(fd, key);
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store_write_pair(fd, key, value);
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} else{
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struct stat st;
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char* contents;
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int i, copy_begin, copy_end, new_line = 0;
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if (value_regex == NULL)
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store.value_regex = NULL;
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else {
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if (value_regex[0] == '!') {
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store.do_not_match = 1;
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value_regex++;
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} else
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store.do_not_match = 0;
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store.value_regex = (regex_t*)malloc(sizeof(regex_t));
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if (regcomp(store.value_regex, value_regex,
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REG_EXTENDED)) {
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fprintf(stderr, "Invalid pattern: %s\n",
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value_regex);
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free(store.value_regex);
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return 6;
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}
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}
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store.offset[0] = 0;
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store.state = START;
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store.seen = 0;
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/*
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* After this, store.offset will contain the *end* offset
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* of the last match, or remain at 0 if no match was found.
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* As a side effect, we make sure to transform only a valid
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* existing config file.
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*/
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if (git_config(store_aux)) {
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fprintf(stderr, "invalid config file\n");
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free(store.key);
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if (store.value_regex != NULL) {
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regfree(store.value_regex);
|
|
free(store.value_regex);
|
|
}
|
|
return 3;
|
|
}
|
|
|
|
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)) {
|
|
close(fd);
|
|
unlink(lock_file);
|
|
return 5;
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
close(fd);
|
|
|
|
if (rename(lock_file, config_filename) < 0) {
|
|
fprintf(stderr, "Could not rename the lock file?\n");
|
|
return 4;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
|