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net_instaweb::SplitUpDownCounter Class Reference

#include "split_statistics.h"

Inheritance diagram for net_instaweb::SplitUpDownCounter:

Public Member Functions

 SplitUpDownCounter (UpDownCounter *rw, UpDownCounter *w)
virtual void Set (int64 new_value)
virtual int64 SetReturningPreviousValue (int64 new_value)
virtual int64 Get () const
virtual StringPiece GetName () const
virtual int64 AddHelper (int64 delta)
 This is virtual so that subclasses can add platform-specific atomicity.
- Public Member Functions inherited from net_instaweb::UpDownCounter
void Clear ()
int64 Add (int64 delta)

Additional Inherited Members

Detailed Description

A statistics variable that forwards writes to two other Variable objects, but reads only from one.

Constructor & Destructor Documentation

net_instaweb::SplitUpDownCounter::SplitUpDownCounter ( UpDownCounter rw,
UpDownCounter w 

UpDownCounter 'rw' will be used to read and write, variable 'w' will be used for writes only. Does not take ownership of either 'rw' or 'w'. 'rw' and 'w' must be non-NULL.

Member Function Documentation

virtual StringPiece net_instaweb::SplitUpDownCounter::GetName ( ) const

Return some name representing the variable, provided that the specific implementation has some sensible way of doing so.

Implements net_instaweb::UpDownCounter.

virtual int64 net_instaweb::SplitUpDownCounter::SetReturningPreviousValue ( int64  value)

Sets the specified value, returning the previous value. This can be used to by two competing threads/processes to determine which thread modified the value first. The default implementation is non-atomic, but implementations can override to provide an atomic version.

Non-atomic implementations may result in multiple concurrent updates each returning the old value. In an atomic implementation, only one concurrent update will return the old value.

Reimplemented from net_instaweb::UpDownCounter.

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