#include <sbuild-lock.h>
Public Types | |
enum | type { LOCK_SHARED = F_RDLCK, LOCK_EXCLUSIVE = F_WRLCK, LOCK_NONE = F_UNLCK } |
Lock type. More... | |
enum | error_code { TIMEOUT_HANDLER, TIMEOUT_SET, TIMEOUT_CANCEL, LOCK, UNLOCK, LOCK_TIMEOUT, UNLOCK_TIMEOUT, DEVICE_LOCK, DEVICE_LOCK_TIMEOUT, DEVICE_TEST, DEVICE_UNLOCK, DEVICE_UNLOCK_TIMEOUT } |
Error codes. More... | |
typedef custom_error< error_code > | error |
Exception type. | |
Public Member Functions | |
virtual void | set_lock (type lock_type, unsigned int timeout)=0 |
Acquire a lock. | |
virtual void | unset_lock ()=0 |
Release a lock. | |
Protected Member Functions | |
lock () | |
The constructor. | |
virtual | ~lock () |
The destructor. | |
void | set_alarm () |
Set the SIGALARM handler. | |
void | clear_alarm () |
Restore the state of SIGALRM prior to starting lock acquisition. | |
void | set_timer (struct itimerval const &timer) |
Set up an itimer for future expiry. | |
void | unset_timer () |
Remove any itimer currently set up. | |
Private Attributes | |
struct sigaction | saved_signals |
Signals saved during timeout. |
This class defines a simple interface for shared and exclusive locks.
typedef custom_error<error_code> sbuild::lock::error |
Exception type.
Error codes.
TIMEOUT_HANDLER | Failed to set timeout handler. |
TIMEOUT_SET | Failed to set timeout. |
TIMEOUT_CANCEL | Failed to cancel timeout. |
LOCK | Failed to lock file. |
UNLOCK | Failed to unlock file. |
LOCK_TIMEOUT | Failed to lock file (timed out). |
UNLOCK_TIMEOUT | Failed to unlock file (timed out). |
DEVICE_LOCK | Failed to lock device. |
DEVICE_LOCK_TIMEOUT | Failed to lock device (timed out). |
DEVICE_TEST | Failed to test device lock. |
DEVICE_UNLOCK | Failed to unlock device. |
DEVICE_UNLOCK_TIMEOUT | Failed to unlock device (timed out). |
enum sbuild::lock::type |
lock::lock | ( | ) | [protected] |
The constructor.
lock::~lock | ( | ) | [protected, virtual] |
The destructor.
void lock::clear_alarm | ( | ) | [protected] |
Restore the state of SIGALRM prior to starting lock acquisition.
References saved_signals.
Referenced by set_timer(), and unset_timer().
void lock::set_alarm | ( | ) | [protected] |
Set the SIGALARM handler.
An error will be thrown on failure.
References saved_signals, and TIMEOUT_HANDLER.
Referenced by set_timer().
virtual void sbuild::lock::set_lock | ( | type | lock_type, | |
unsigned int | timeout | |||
) | [pure virtual] |
void lock::set_timer | ( | struct itimerval const & | timer | ) | [protected] |
Set up an itimer for future expiry.
This is used to interrupt system calls. This will set a handler for SIGALRM as a side effect (using set_alarm).
An error will be thrown on failure.
timer | the timeout to set. |
References clear_alarm(), set_alarm(), and TIMEOUT_SET.
Referenced by sbuild::device_lock::set_lock(), and sbuild::file_lock::set_lock().
virtual void sbuild::lock::unset_lock | ( | ) | [pure virtual] |
Release a lock.
This is equivalent to set_lock with a lock_type of LOCK_NONE and a timeout of 0.
Implemented in sbuild::file_lock, and sbuild::device_lock.
void lock::unset_timer | ( | ) | [protected] |
Remove any itimer currently set up.
This will clear any SIGALRM handler (using clear_alarm).
An error will be thrown on failure.
References clear_alarm(), and TIMEOUT_CANCEL.
Referenced by sbuild::device_lock::set_lock(), and sbuild::file_lock::set_lock().
struct sigaction sbuild::lock::saved_signals [read, private] |