Michael Davidsaver
24f3478c98
Added "safety" of passing move-able reference is an illusion since no use_count()==1 test is done. Instead extra (shallow) copies were made for each subscriber. Instead. Pass const reference, redefine MonitorControlOp::post() to transfer ownership, and make only a single copy in SharedPV::post().
106 lines
3.0 KiB
C++
106 lines
3.0 KiB
C++
/**
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* Copyright - See the COPYRIGHT that is included with this distribution.
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* pvxs is distributed subject to a Software License Agreement found
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* in file LICENSE that is included with this distribution.
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*/
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/**
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* Serves a single PV name.
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* Any updates written (PUT) to this PV will be stored verbatim
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* and sent to any subscribers.
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*/
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#include <iostream>
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#include <epicsTime.h>
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#include <pvxs/sharedpv.h>
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#include <pvxs/server.h>
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#include <pvxs/nt.h>
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#include <pvxs/log.h>
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using namespace pvxs;
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int main(int argc, char* argv[])
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{
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if(argc<=1) {
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std::cerr<<"Usage: "<<argv[0]<<" <pvname>\n";
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return 1;
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}
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// Read $PVXS_LOG from process environment and update
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// logging configuration. eg.
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// export PVXS_LOG=*=DEBUG
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// makes a lot of noise.
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logger_config_env();
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// Must provide a data type for the mailbox.
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// Use pre-canned definition of scalar with meta-data
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Value initial = nt::NTScalar{TypeCode::Float64}.create();
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// (optional) Provide an initial value
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initial["value"] = 42.0;
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initial["alarm.severity"] = 0;
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initial["alarm.status"] = 0;
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initial["alarm.message"] = "";
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// Actually creating the mailbox PV.
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// buildMailbox() installs a default onPut() handler which
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// stores whatever a client sends (subject to our data type).
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server::SharedPV pv(server::SharedPV::buildMailbox());
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// (optional) Replace the default PUT handler to do a range check
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pv.onPut([](server::SharedPV& pv,
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std::unique_ptr<server::ExecOp>&& op,
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Value&& top)
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{
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// (optional) arbitrarily clip value to [-100.0, 100.0]
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double val(top["value"].as<double>());
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if(val<-100.0)
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top["value"] = -100.0;
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else if(val>100.0)
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top["value"] = 100.0;
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// (optional) Provide a timestamp if the client has not (common)
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Value ts(top["timeStamp"]);
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if(!ts.isMarked(true, true)) {
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// use current time
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epicsTimeStamp now;
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if(!epicsTimeGetCurrent(&now)) {
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ts["secondsPastEpoch"] = now.secPastEpoch + POSIX_TIME_AT_EPICS_EPOCH;
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ts["nanoseconds"] = now.nsec;
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}
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}
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// (optional) update the SharedPV cache and send
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// a update to any subscribers
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pv.post(top);
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// Required. Inform client that PUT operation is complete.
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op->reply();
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});
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// Associate a data type (and maybe initial value) with this PV
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pv.open(initial);
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// Build server which will server this PV
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// Configure using process environment.
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server::Server serv = server::Config::fromEnv()
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.build()
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.addPV(argv[1], pv);
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// (optional) Print the configuration this server is using
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// with any auto-address list expanded.
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std::cout<<"Effective config\n"<<serv.config();
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std::cout<<"Running\n";
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// Start server and run forever, or until Ctrl+c is pressed.
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// Returns on SIGINT or SIGTERM
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serv.run();
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std::cout<<"Done\n";
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return 0;
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}
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