sbuild::lock Class Reference

Advisory locking. More...

#include <sbuild-lock.h>

Inheritance diagram for sbuild::lock:

[legend]List of all members.

Public Types
typedef runtime_error_custom< lock >	error
	Exception type.
enum	type { LOCK_SHARED = F_RDLCK, LOCK_EXCLUSIVE = F_WRLCK, LOCK_NONE = F_UNLCK }
	Lock type. More...
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
sigaction	saved_signals
	Signals saved during timeout.

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Detailed Description

Advisory locking.

This class defines a simple interface for shared and exclusive locks.

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Member Typedef Documentation

typedef runtime_error_custom<lock> sbuild::lock::error

Exception type.

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Member Enumeration Documentation

enum sbuild::lock::type

Lock type. Enumerator: LOCK_SHARED  A shared (read) lock. LOCK_EXCLUSIVE  An exclusive (write) lock. LOCK_NONE  No lock.

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Constructor & Destructor Documentation

lock::lock (   )  [protected]

The constructor.

lock::~lock (   )  [protected, virtual]

The destructor.

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Member Function Documentation

void lock::clear_alarm (   )  [protected]

Restore the state of SIGALRM prior to starting lock acquisition.

void lock::set_alarm (   )  [protected]

Set the SIGALARM handler. An error will be thrown on failure.

virtual void sbuild::lock::set_lock (  type  lock_type, unsigned int  timeout )  [pure virtual]

Acquire a lock. Parameters: lock_type  the type of lock to acquire. timeout  the time in seconds to wait on the lock.

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. Parameters: timer  the timeout to set.

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.

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Member Data Documentation

struct sigaction sbuild::lock::saved_signals [private]

Signals saved during timeout.

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The documentation for this class was generated from the following files:

• schroot/sbuild-lock.h
• schroot/sbuild-lock.cc

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