A wrapper around the UNIX file locking mechanism. More...

#include <File_Lock.h>

Collaboration diagram for ACE_File_Lock:

Public Member Functions
	ACE_File_Lock (ACE_HANDLE handle=ACE_INVALID_HANDLE, bool unlink_in_destructor=true)

	ACE_File_Lock (const ACE_TCHAR *filename, int flags, mode_t mode=0, bool unlink_in_destructor=true)

int	open (const ACE_TCHAR *filename, int flags, mode_t mode=0)

	~ACE_File_Lock (void)
	Remove a File lock by releasing it and closing down the <handle_>. More...

int	remove (bool unlink_file=true)

int	acquire (short whence=0, ACE_OFF_T start=0, ACE_OFF_T len=1)

int	tryacquire (short whence=0, ACE_OFF_T start=0, ACE_OFF_T len=1)

int	release (short whence=0, ACE_OFF_T start=0, ACE_OFF_T len=1)
	Unlock a readers/writer lock. More...

int	acquire_write (short whence=0, ACE_OFF_T start=0, ACE_OFF_T len=1)

int	tryacquire_write (short whence=0, ACE_OFF_T start=0, ACE_OFF_T len=1)

int	tryacquire_write_upgrade (short whence=0, ACE_OFF_T start=0, ACE_OFF_T len=1)

int	acquire_read (short whence=0, ACE_OFF_T start=0, ACE_OFF_T len=1)

int	tryacquire_read (short whence=0, ACE_OFF_T start=0, ACE_OFF_T len=1)

ACE_HANDLE	get_handle (void) const
	Get underlying ACE_HANDLE for the file. More...

void	set_handle (ACE_HANDLE)

void	dump (void) const
	Dump state of the object. More...

Public Attributes
	ACE_ALLOC_HOOK_DECLARE
	Declare the dynamic allocation hooks. More...

Protected Attributes
ACE_OS::ace_flock_t	lock_
	Locking structure for OS record locks. More...

bool	removed_

bool const	unlink_in_destructor_

Private Member Functions
void	operator= (const ACE_File_Lock &)

	ACE_File_Lock (const ACE_File_Lock &)

Detailed Description

A wrapper around the UNIX file locking mechanism.

Allows us to "adapt" the UNIX file locking mechanisms to work with all of our Guard stuff...

Constructor & Destructor Documentation

ACE_File_Lock::ACE_File_Lock	(	ACE_HANDLE	handle = `ACE_INVALID_HANDLE`,
		bool	unlink_in_destructor = `true`
	)

Set the <handle_> of the File_Lock to handle. Note that this constructor assumes ownership of the handle and will close it down in <remove>. If you want the handle to stay open when <remove> is called make sure to call <dup> on the handle. If you don't want the file unlinked in the destructor pass a zero value for <unlink_in_destructor>.

ACE_File_Lock::ACE_File_Lock	(	const ACE_TCHAR *	filename,
		int	flags,
		mode_t	mode = `0`,
		bool	unlink_in_destructor = `true`
	)

Open the filename with flags and mode and set the result to <handle_>. If you don't want the file unlinked in the destructor pass a false value for unlink_in_destructor.

ACE_File_Lock::~ACE_File_Lock ( void )

Remove a File lock by releasing it and closing down the <handle_>.

ACE_File_Lock::ACE_File_Lock ( const ACE_File_Lock & )

private

Member Function Documentation

int ACE_File_Lock::acquire	(	short	whence = `0`,
		ACE_OFF_T	start = `0`,
		ACE_OFF_T	len = `1`
	)

inline

Note, for interface uniformity with other synchronization wrappers we include the acquire() method. This is implemented as a write-lock to be on the safe-side...

int ACE_File_Lock::acquire_read	(	short	whence = `0`,
		ACE_OFF_T	start = `0`,
		ACE_OFF_T	len = `1`
	)

inline

Acquire a read lock, but block if a writer hold the lock. Returns -1 on failure. If we "failed" because someone else already had the lock, errno is set to EBUSY.

int ACE_File_Lock::acquire_write	(	short	whence = `0`,
		ACE_OFF_T	start = `0`,
		ACE_OFF_T	len = `1`
	)

inline

Acquire a write lock, but block if any readers or a writer hold the lock.

void ACE_File_Lock::dump ( void ) const

Dump state of the object.

ACE_HANDLE ACE_File_Lock::get_handle ( void ) const

inline

Get underlying ACE_HANDLE for the file.

int ACE_File_Lock::open	(	const ACE_TCHAR *	filename,
		int	flags,
		mode_t	mode = `0`
	)

Open the filename with flags and mode and set the result to <handle_>.

void ACE_File_Lock::operator= ( const ACE_File_Lock & )

private

int ACE_File_Lock::release	(	short	whence = `0`,
		ACE_OFF_T	start = `0`,
		ACE_OFF_T	len = `1`
	)

inline

Unlock a readers/writer lock.

int ACE_File_Lock::remove ( bool unlink_file = true )

inline

Remove a File lock by releasing it and closing down the <handle_>. If unlink_file is true then we unlink the file.

void ACE_File_Lock::set_handle ( ACE_HANDLE h )

inline

Set underlying ACE_HANDLE. Note that this method assumes ownership of the handle and will close it down in <remove>. If you want the handle to stay open when <remove> is called make sure to call <dup> on the handle before closing it. You are responsible for the closing the existing handle before overwriting it.

int ACE_File_Lock::tryacquire	(	short	whence = `0`,
		ACE_OFF_T	start = `0`,
		ACE_OFF_T	len = `1`
	)

inline

Note, for interface uniformity with other synchronization wrappers we include the <tryacquire> method. This is implemented as a write-lock to be on the safe-side... Returns -1 on failure. If we "failed" because someone else already had the lock, errno is set to EBUSY.

int ACE_File_Lock::tryacquire_read	(	short	whence = `0`,
		ACE_OFF_T	start = `0`,
		ACE_OFF_T	len = `1`
	)

inline

Conditionally acquire a read lock (i.e., won't block). Returns -1 on failure. If we "failed" because someone else already had the lock, errno is set to EBUSY.

int ACE_File_Lock::tryacquire_write	(	short	whence = `0`,
		ACE_OFF_T	start = `0`,
		ACE_OFF_T	len = `1`
	)

inline

Conditionally acquire a write lock (i.e., won't block). Returns -1 on failure. If we "failed" because someone else already had the lock, errno is set to EBUSY.

int ACE_File_Lock::tryacquire_write_upgrade	(	short	whence = `0`,
		ACE_OFF_T	start = `0`,
		ACE_OFF_T	len = `1`
	)

inline

Conditionally upgrade to a write lock (i.e., won't block). Returns -1 on failure. If we "failed" because someone else already had the lock, errno is set to EBUSY.

Member Data Documentation

ACE_File_Lock::ACE_ALLOC_HOOK_DECLARE

Declare the dynamic allocation hooks.

ACE_OS::ace_flock_t ACE_File_Lock::lock_

protected

Locking structure for OS record locks.

bool ACE_File_Lock::removed_

protected

Keeps track of whether <remove> has been called yet to avoid multiple <remove> calls, e.g., explicitly and implicitly in the destructor. This flag isn't protected by a lock, so make sure that you don't have multiple threads simultaneously calling <remove> on the same object, which is a bad idea anyway...

bool const ACE_File_Lock::unlink_in_destructor_

protected

Keeps track of whether to unlink the underlying file in the destructor.

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

Public Member Functions

Public Attributes

Protected Attributes

Private Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation