#ifdef USE_PCH
 #include "pch.h"
#else
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/ipc.h>
 #include <sys/sem.h>
 #include <errno.h>
 #include <iostream>
 #include <fstream>
 #include <cassert>
 #include "sitecing/sitecing_util.h"
#endif

namespace sitecing {

    /*
     * XXX: all of these utilities could be sheerly optimized.
     */

    string strip_prefix(const string& str,const string& prefix) {
	if( (str.length()<prefix.length()) || str.compare(0,prefix.length(),prefix))
	    throw utility_no_prefix(CODEPOINT,"no such prefix");
	return str.substr(prefix.length());
    }

    string strip_suffix(const string& str,const string& suffix) {
	if( (str.length()<suffix.length()) || str.compare(str.length()-suffix.length(),suffix.length(),suffix))
	    throw utility_no_suffix(CODEPOINT,"no such suffix");
	return str.substr(0,str.length()-suffix.length());
    }

    void file_lock::lock(const string& f) {
	unlock();
	fd = open(f.c_str(),O_CREAT|O_RDWR,S_IRUSR|S_IWUSR);
	if(fd<0)
	    throw konforka::exception(CODEPOINT,"failed to open/create lockfile");
	try {
	    lock();
	}catch(konforka::exception& ke) {
	    ke.see(CODEPOINT);
	    close(fd); fd=-1;
	    throw;
	}catch(...) {
	    close(fd); fd=-1;
	    throw;
	}
    }
    void file_lock::lock() {
	assert(fd>=0);
	struct flock fl;
	fl.l_type = F_WRLCK;
	fl.l_whence=SEEK_SET;
	fl.l_start=fl.l_len=0;
	for(int tries=3;tries;tries--) {
	    if(!fcntl(fd,F_SETLK,&fl))
		return;
	    sleep(8);
	}
	throw konforka::exception(CODEPOINT,"failed to obtain file lock");
    }
    void file_lock::unlock() {
	if(fd<0)
	    return;
	struct flock fl;
	fl.l_type = F_UNLCK;
	fl.l_whence=SEEK_SET;
	fl.l_start=fl.l_len=0;
	int rv = fcntl(fd,F_SETLK,&fl);
	close(fd);
	fd=-1;
	if(rv)
	    throw konforka::exception(CODEPOINT,"failed to release file lock");
    }

    void pid_file::set(const string& f,bool u) {
	ofstream of(f.c_str(),ios::trunc);
	if(!of)
	    throw konforka::exception(CODEPOINT,"failed to open file for writing pid");
	of << getpid() << endl;
	of.close();
	file_name = f;
	unlink_pid = u;
    }
    void pid_file::unlink() {
	if(!unlink_pid)
	    return;
	::unlink(file_name.c_str());
    }

    void semaphore::init() {
	deinit();
	semid = semget(IPC_PRIVATE,1,IPC_CREAT|0600);
	if(semid<0)
	    throw konforka::exception(CODEPOINT,"failed to semget()");
	if(semctl(semid,0,SETVAL,1))
	    throw konforka::exception(CODEPOINT,"failed to semctl()");
    }
    void semaphore::deinit() {
	if(semid<0)
	    return;
	semctl(semid,0,IPC_RMID,0);
    }
    void semaphore::on() {
	assert(semid>=0);
	struct sembuf sb;
	sb.sem_num=0;
	sb.sem_op=-1;
	sb.sem_flg = SEM_UNDO;
	while(semop(semid,&sb,1)<0) {
	    if(errno!=EINTR)
		throw konforka::exception(CODEPOINT,"failed to semop()");
	}
    }
    void semaphore::off() {
	assert(semid>=0);
	struct sembuf sb;
	sb.sem_num=0;
	sb.sem_op=1;
	sb.sem_flg = SEM_UNDO;
	while(semop(semid,&sb,1)<0) {
	    if(errno!=EINTR)
		throw konforka::exception(CODEPOINT,"failed to semop()");
	}
    }

    void semaphore_lock::lock() {
	assert(sem);
	if(locked)
	    return;
	sem->on();
	locked = true;
    }
    void semaphore_lock::unlock() {
	if(!sem)
	    return;
	if(!locked)
	    return;
	sem->off();
	locked=false;
    }

    void auto_chdir::pushdir(const string& td,bool ap) {
	/* TODO: make use of fchdir(2) instead */
	char *tmp = getcwd(0,0);
	assert(tmp);
	saved_pwd = tmp;
	free(tmp);
	autopop=ap;
	if(chdir(td.c_str()))
	    throw konforka::exception(CODEPOINT,"failed to chdir()");
    }
    void auto_chdir::popdir() {
	autopop=false;
	if(chdir(saved_pwd.c_str()))
	    throw konforka::exception(CODEPOINT,"failed to chdir()");
	// XXX: or should it be thrown? after all we call it from destructor...
    }

}