|
Bugzilla – Full Text Bug Listing |
| Summary: | FlowMonitor returns containers copies instead of references | ||
|---|---|---|---|
| Product: | ns-3 | Reporter: | Tommaso Pecorella <tommaso.pecorella> |
| Component: | python bindings | Assignee: | Gustavo J. A. M. Carneiro <gjcarneiro> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | ns-bugs, tomh |
| Priority: | P5 | ||
| Version: | ns-3-dev | ||
| Hardware: | All | ||
| OS: | All | ||
| Attachments: | patch | ||
Created attachment 1874 [details]
patch
Added containers typedefs and return containers const references.
changeset: 10962:8beb54fffadc The new API is not working with pybindgen.
Old API was:
std::map<FlowId, FlowStats> GetFlowStats () const;
Binding:
## flow-monitor.h (module 'flow-monitor'): std::map<unsigned int, ns3::FlowMonitor::FlowStats, std::less<unsigned int>, std::allocator<std::pair<unsigned int const, ns3::FlowMonitor::FlowStats> > > ns3::FlowMonitor::GetFlowStats() const [member function]
cls.add_method('GetFlowStats',
'std::map< unsigned int, ns3::FlowMonitor::FlowStats >',
[],
is_const=True)
This is the new API:
typedef std::map<FlowId, FlowStats> FlowStatsContainer;
const FlowStatsContainer& GetFlowStats () const;
and its binding:
## flow-monitor.h (module 'flow-monitor'): std::map<unsigned int, ns3::FlowMonitor::FlowStats, std::less<unsigned int>, std::allocator<std::pair<unsigned int const, ns3::FlowMonitor::FlowStats> > > ns3::FlowMonitor::GetFlowStats() const [member function]
cls.add_method('GetFlowStats',
'std::map< unsigned int, ns3::FlowMonitor::FlowStats > &',
[],
is_const=True)
However, the build log reports:
DEBUG:pybindgen.typehandlers:TypeMatcher.lookup('std::map< unsigned int, ns3::FlowMonitor::FlowStats > const &')
DEBUG:pybindgen.typehandlers:try to lookup type handler for 'std::map< unsigned int, ns3::FlowMonitor::FlowStats > const &' => failure
'std::map< unsigned int, ns3::FlowMonitor::FlowStats > const &' did not match
.../ns-3-dev/src/flow-monitor/bindings/modulegen__gcc_LP64.py:4251: Warning: exception TypeLookupError(['std::map< unsigned int, ns3::FlowMonitor::FlowStats > &'],) in wrapper public: retval? ???::GetFlowStats (params?) const;
is_const=True)
This doesn't seem limited to this method; GetAllProbes() also does not have a binding. Seems like pybindgen may not handle returning const references to containers.
I should be able to tweak pybindgen to handle these cases. Of course, PBG will have to copy the value anyway, but you cannot escape that in Python. fixed in changeset 6015cf72891f |
The following line seems to be right, but it leads to an infinite loop: std::map<FlowId, FlowMonitor::FlowStats>::iterator j; for (j = monitor->GetFlowStats().begin(); j != monitor->GetFlowStats().end(); j++) {...} GetFlowStats() should return a const reference to the inner container, not a copy of it. Otherwise the two unction calls will return different containers, with different iterators, and the loop will behave in funny way.