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Read and writes are cached, so they are done only once on the route, not matter how many time the filter requests or writes the variable.
Because of this caching, the SingleVarRW is usuable only once. After it has done its work once, it has to be re-created.
| SingleVarRWErr (class) | SingleVarRWErr |
| SingleVarRW ()
| SingleVarRW |
| ~SingleVarRW ()
| ~SingleVarRW |
[virtual]
| const Element& read (const Id& id)
| read |
Implementation of VarRW read.
Parameters:
| id | identifier of variable to be read. |
Returns: variable requested.
Reimplemented from VarRW.
| void write (const Id& id, const Element& e)
| write |
Implementation of VarRW write.
Parameters:
| id | identifier of variable to be written to. |
| e | value of variable to be written to. |
Reimplemented from VarRW.
| void sync ()
| sync |
Implementation of VarRW sync.
Writes are performed now, as cached Element* pointers may become invalid afterwards.a
trash is also emptied upon completion.
Reimplemented from VarRW.
| void initialize (const Id& id, Element* e)
| initialize |
Register a variable for read access with SingleVarRW. SingleVarRW owns the element, so derived classes do not need to worry about deleting objects.
All supported variables must be registered, even the ones not present in the current route. For example v6 nexthops must be set to ElemNull on v4 routes. [assuming the protocol itself supports v6].
Parameters:
| id | identifier of variable that may be read. |
| e | value of variable. |
| void initialize (PolicyTags& pt)
| initialize |
| void start_read ()
| start_read |
[virtual]
If any reads are performed, this is a marker which informs the derived class that reads will now start.
| void start_write ()
| start_write |
[virtual]
If any writes were performed, this is a marker which informs the derived class that writes will start.
| void single_write (const Id& id, const Element& e)
| single_write |
[pure virtual]
Write of a variable. The write MUST be performed now, as the element pointer may become invalid after this call. Also, a single write will be called for each modified element.
Parameters:
| id | identifier of variable to be written to. |
| e | value of variable. |
| Element* single_read (const Id& id)
| single_read |
[pure virtual]
Read of a variable. The VarRW needs to read a particular element. This may return NULL indicating ElemNull---i.e. variable not present in THIS route.
Parameters:
| id | the id of the variable. |
Returns: variable requested.
| void end_write ()
| end_write |
[virtual]
Marks the end of writes in case there were any modified fields.
