Page Speed Optimization Libraries
1.2.24.1
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#include "split_statistics.h"
Public Member Functions | |
SplitVariable (Variable *rw, Variable *w) | |
virtual void | Set (int64 new_value) |
virtual int64 | SetReturningPreviousValue (int64 new_value) |
virtual int64 | Get () const |
virtual StringPiece | GetName () const |
virtual int64 | Add (int delta) |
A statistics variable that forwards writes to two other Variable objects, but reads only from one.
net_instaweb::SplitVariable::SplitVariable | ( | Variable * | rw, |
Variable * | w | ||
) |
Variable '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.
virtual int64 net_instaweb::SplitVariable::Add | ( | int | delta | ) | [virtual] |
Adds 'delta' to the variable's value, returning the result. This is virtual so that subclasses can add platform-specific atomicity.
Reimplemented from net_instaweb::Variable.
virtual StringPiece net_instaweb::SplitVariable::GetName | ( | ) | const [virtual] |
Return some name representing the variable, provided that the specific implementation has some sensible way of doing so.
Implements net_instaweb::Variable.
virtual int64 net_instaweb::SplitVariable::SetReturningPreviousValue | ( | int64 | value | ) | [virtual] |
Sets the specified value, returning the previous value. This can be used to by two competing threads/processes to deterimine 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::Variable.