Add error handling to SCA publish

Author: PascalBoeschoten

src/CommandLineUtilities/AliceLowlevelFrontend/ProgramAliceLowlevelFrontendServer.cxx

@@ -184,13 +184,21 @@ class PublisherRegistry
               }
             },
             [&](const ServiceDescription::ScaSequence& type){
+              std::fill(registerValues.begin(), registerValues.end(), 0); // Reset array in case of aborts
               auto sca = Sca(channel, channel.getCardType());
               for (size_t i = 0; i < type.commandDataPairs.size(); ++i) {
-                const auto& pair = type.commandDataPairs[i];
-                sca.write(pair);
-                auto result = sca.read();
-                registerValues[i*2] = result.command;
-                registerValues[i*2 + 1] = result.data;
+                try {
+                  const auto& pair = type.commandDataPairs[i];
+                  sca.write(pair);
+                  auto result = sca.read();
+                  registerValues[i*2] = result.command;
+                  registerValues[i*2 + 1] = result.data;
+                } catch (const ScaException &e) {
+                  // If an SCA error occurs, we stop executing the sequence of commands and set the error value
+                  registerValues[i*2] = 0xffffffff;
+                  registerValues[i*2 + 1] = 0xffffffff;
+                  break;
+                }
               }
             }
           );

src/CommandLineUtilities/AliceLowlevelFrontend/README.md

@@ -36,7 +36,8 @@ Values are published as array of 32 bit unsigned integers.
 
 #### Publish SCA
 Starts a service under a DNS name, that executes and publishes the results of the given SCA write sequence at the 
-specified interval. Values are published as array of 32 bit unsigned integers. 
+specified interval. Values are published as array of 32 bit unsigned integers.
+If an error occurred, the corresponding result will be set to 0xffffffff and the rest of the sequence is aborted. 
 * Service type: RPC call
 * Service name: PUBLISH_SCA_START
 * Parameters: DNS name to publish at, comma-separated register addresses, interval in seconds