ACE_File_Lock Class Reference

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

#include <File_Lock.h>

Collaboration diagram for ACE_File_Lock:

Collaboration graph
[legend]
List of all members.

Public Member Functions

 ACE_File_Lock (ACE_HANDLE handle=ACE_INVALID_HANDLE, int unlink_in_destructor=1)
 ACE_File_Lock (const ACE_TCHAR *filename, int flags, mode_t mode=0, int unlink_in_destructor=1)
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_>.
int remove (int unlink_file=1)
int acquire (short whence=0, off_t start=0, off_t len=1)
int tryacquire (short whence=0, off_t start=0, off_t len=1)
int release (short whence=0, off_t start=0, off_t len=1)
 Unlock a readers/writer lock.
int acquire_write (short whence=0, off_t start=0, off_t len=1)
int tryacquire_write (short whence=0, off_t start=0, off_t len=1)
int tryacquire_write_upgrade (short whence=0, off_t start=0, off_t len=1)
int acquire_read (short whence=0, off_t start=0, off_t len=1)
int tryacquire_read (short whence=0, off_t start=0, off_t len=1)
ACE_HANDLE get_handle (void) const
 Get underlying <ACE_HANDLE> for the file.
void set_handle (ACE_HANDLE)
void dump (void) const
 Dump state of the object.

Public Attributes

 ACE_ALLOC_HOOK_DECLARE
 Declare the dynamic allocation hooks.

Protected Attributes

ACE_OS::ace_flock_t lock_
 Locking structure for OS record locks.
int removed_
int 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,
int  unlink_in_destructor = 1
 

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,
int  unlink_in_destructor = 1
 

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 zero 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

ACE_INLINE int ACE_File_Lock::acquire short  whence = 0,
off_t  start = 0,
off_t  len = 1
 

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...

ACE_INLINE int ACE_File_Lock::acquire_read short  whence = 0,
off_t  start = 0,
off_t  len = 1
 

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>.

ACE_INLINE int ACE_File_Lock::acquire_write short  whence = 0,
off_t  start = 0,
off_t  len = 1
 

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_INLINE ACE_HANDLE ACE_File_Lock::get_handle void   )  const
 

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]
 

ACE_INLINE int ACE_File_Lock::release short  whence = 0,
off_t  start = 0,
off_t  len = 1
 

Unlock a readers/writer lock.

ACE_INLINE int ACE_File_Lock::remove int  unlink_file = 1  ) 
 

Remove a File lock by releasing it and closing down the <handle_>. If <unlink_file> is non-0 then we unlink the file.

ACE_INLINE void ACE_File_Lock::set_handle ACE_HANDLE   ) 
 

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.

ACE_INLINE int ACE_File_Lock::tryacquire short  whence = 0,
off_t  start = 0,
off_t  len = 1
 

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>.

ACE_INLINE int ACE_File_Lock::tryacquire_read short  whence = 0,
off_t  start = 0,
off_t  len = 1
 

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>.

ACE_INLINE int ACE_File_Lock::tryacquire_write short  whence = 0,
off_t  start = 0,
off_t  len = 1
 

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>.

ACE_INLINE int ACE_File_Lock::tryacquire_write_upgrade short  whence = 0,
off_t  start = 0,
off_t  len = 1
 

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.

int 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...

int 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:
Generated on Wed Nov 23 15:48:41 2005 for ACE by  doxygen 1.4.5