UCommon
Data Structures | Public Member Functions | Static Public Member Functions | Protected Member Functions | Protected Attributes
ucommon::ThreadLock Class Reference

A generic and portable implimentation of Read/Write locking. More...

#include <thread.h>

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Data Structures

class  guard_reader
 Guard class to apply scope based access locking to objects. More...
 
class  guard_writer
 Guard class to apply scope based exclusive locking to objects. More...
 

Public Member Functions

bool access (timeout_t timeout=Timer::inf)
 Request shared (read) access through the lock. More...
 
bool modify (timeout_t timeout=Timer::inf)
 Request modify (write) access through the lock. More...
 
void release (void)
 Release the lock.
 
 ThreadLock ()
 Create an instance of a rwlock.
 
- Public Member Functions inherited from ucommon::ExclusiveAccess
void exclusive_lock (void)
 Access interface to exclusive lock the object.
 
void release_exclusive (void)
 Access interface to release a lock.
 
- Public Member Functions inherited from ucommon::SharedAccess
virtual void exclusive (void)
 Convert object to an exclusive lock. More...
 
void release_share (void)
 
virtual void share (void)
 Share the lock with other referencers. More...
 
void shared_lock (void)
 

Static Public Member Functions

static void indexing (unsigned size)
 Specify hash table size for guard protection. More...
 
static bool reader (const void *object, timeout_t timeout=Timer::inf)
 Shared access to an arbitrary object. More...
 
static void release (const void *object)
 Release an arbitrary object that has been protected by a rwlock. More...
 
static bool writer (const void *object, timeout_t timeout=Timer::inf)
 Write protect access to an arbitrary object. More...
 

Protected Member Functions

virtual void _lock (void)
 
virtual void _share (void)
 Access interface to share lock the object.
 
virtual void _unlock (void)
 

Protected Attributes

pthread_t writeid
 
unsigned writers
 

Additional Inherited Members

- Private Member Functions inherited from ucommon::ConditionalAccess
void access (void)
 Access mode shared thread scheduling.
 
void commit (void)
 Complete exclusive mode write scheduling.
 
 ConditionalAccess ()
 Initialize and construct conditional.
 
void limit_sharing (unsigned max)
 Specify a maximum sharing (access) limit. More...
 
void modify (void)
 Exclusive mode write thread scheduling.
 
void release (void)
 Release access mode read scheduling.
 
 ~ConditionalAccess ()
 Destroy conditional, release any blocked threads.
 
void broadcast (void)
 Signal the conditional to release all broadcast threads.
 
void lock (void)
 Lock the conditional's supporting mutex.
 
void signal (void)
 Signal the conditional to release one signalled thread.
 
void unlock (void)
 Unlock the conditional's supporting mutex.
 
bool waitBroadcast (timeout_t timeout)
 Conditional wait for broadcast on millisecond timeout. More...
 
bool waitBroadcast (struct timespec *timeout)
 Conditional wait for broadcast on timespec timeout. More...
 
void waitBroadcast (void)
 Wait (block) until broadcast.
 
bool waitSignal (timeout_t timeout)
 Conditional wait for signal on millisecond timeout. More...
 
bool waitSignal (struct timespec *timeout)
 Conditional wait for signal on timespec timeout. More...
 
void waitSignal (void)
 Wait (block) until signalled.
 

Detailed Description

A generic and portable implimentation of Read/Write locking.

This class impliments classical read/write locking, including "timed" locks. Support for scheduling threads to avoid writer starvation is also provided for. By building read/write locks from a conditional, we make them available on pthread implimetations and other platforms which do not normally include optional pthread rwlock's. We also do not restrict the number of threads that may use the lock. Finally, both the exclusive and shared protocols are implimented to support exclusive_lock and shared_lock referencing.

Author
David Sugar dyfet.nosp@m.@gnu.nosp@m.telep.nosp@m.hony.nosp@m..org

Definition at line 498 of file thread.h.

Member Function Documentation

bool ucommon::ThreadLock::access ( timeout_t  timeout = Timer::inf)

Request shared (read) access through the lock.

Parameters
timeoutin milliseconds to wait for lock.
Returns
true if locked, false if timeout.
static void ucommon::ThreadLock::indexing ( unsigned  size)
static

Specify hash table size for guard protection.

The default is 1. This should be called at initialization time from the main thread of the application before any other threads are created.

Parameters
sizeof hash table used for guarding.
bool ucommon::ThreadLock::modify ( timeout_t  timeout = Timer::inf)

Request modify (write) access through the lock.

Parameters
timeoutin milliseconds to wait for lock.
Returns
true if locked, false if timeout.
static bool ucommon::ThreadLock::reader ( const void *  object,
timeout_t  timeout = Timer::inf 
)
static

Shared access to an arbitrary object.

This is based on the protect function of mutex.

Parameters
objectto share.
timeoutin milliseconds to wait for lock.
Returns
true if shared, false if timeout.
static void ucommon::ThreadLock::release ( const void *  object)
static

Release an arbitrary object that has been protected by a rwlock.

Parameters
objectto release.
static bool ucommon::ThreadLock::writer ( const void *  object,
timeout_t  timeout = Timer::inf 
)
static

Write protect access to an arbitrary object.

This is like the protect function of mutex.

Parameters
objectto protect.
timeoutin milliseconds to wait for lock.
Returns
true if locked, false if timeout.

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