/*
 * Copyright (c) 2005, Junio C Hamano
 */
#include <signal.h>
#include "cache.h"

static struct lock_file *lock_file_list;

static void remove_lock_file(void)
{
        while (lock_file_list) {
                if (lock_file_list->filename[0])
                        unlink(lock_file_list->filename);
                lock_file_list = lock_file_list->next;
        }
}

static void remove_lock_file_on_signal(int signo)
{
        remove_lock_file();
        signal(SIGINT, SIG_DFL);
        raise(signo);
}

int hold_lock_file_for_update(struct lock_file *lk, const char *path)
{
        int fd;
        sprintf(lk->filename, "%s.lock", path);
        fd = open(lk->filename, O_RDWR | O_CREAT | O_EXCL, 0666);
        if (fd >=0 && !lk->next) {
                lk->next = lock_file_list;
                lock_file_list = lk;
                signal(SIGINT, remove_lock_file_on_signal);
                atexit(remove_lock_file);
        }
        return fd;
}

int commit_lock_file(struct lock_file *lk)
{
        char result_file[PATH_MAX];
        int i;
        strcpy(result_file, lk->filename);
        i = strlen(result_file) - 5; /* .lock */
        result_file[i] = 0;
        i = rename(lk->filename, result_file);
        lk->filename[0] = 0;
        return i;
}

void rollback_lock_file(struct lock_file *lk)
{
        if (lk->filename[0])
                unlink(lk->filename);
        lk->filename[0] = 0;
}