ELEUDAQ2: pass on calibration file to EUDAQ2 decoder

(cherry picked from commit 264f1ad9)

src/modules/EventLoaderEUDAQ2/EventLoaderEUDAQ2.cpp

@@ -35,6 +35,13 @@ EventLoaderEUDAQ2::EventLoaderEUDAQ2(Configuration config, std::shared_ptr<Detec
         cfg.Set(key.first, key.second);
     }
 
+    // In addition, also provide the calibration file specified in the detector geometry:
+    auto calibration_file = m_detector->calibrationFile();
+    if(!calibration_file.empty()) {
+        LOG(DEBUG) << "Forwarding detector calibration file: " << calibration_file;
+        cfg.Set("calibration_file", calibration_file);
+    }
+
     // Converting the newly built configuration to a shared pointer of a cont configuration object
     // Unfortunbately EUDAQ does not provide appropriate member functions for their configuration class to avoid this dance
     const eudaq::Configuration eu_cfg = cfg;

src/modules/EventLoaderEUDAQ2/README.md

@@ -58,6 +58,7 @@ cmake -DUSER_CARIBOU_BUILD=ON ..
 ### Contract between EUDAQ Decoder and EventLoader
 
 The decoder guarantees to
+
 * return `true` only when there is a fully decoded event available and `false` in all other cases.
 * not return any event before a possible T0 signal in the data. This is a signal that indicates the clock reset at the beginning of the run. It can be a particular data word or the observation of the pixel timestamp jumping back to zero, depending on data format of each the detector.
 * return the smallest possible granularity of data in time either as even or as sub-events within one event.
@@ -72,6 +73,8 @@ It should be kept in mind that the resulting configuration strings are parsed by
 For example, it does not interpret `true` or `false` alphabetic value of a Boolean variable but will return false in both cases. Thus `key = 0` or `key = 1` have to be used in these cases.
 Also, more complex constructs such as arrays or matrices read by the Corryvreckan configuration are simply interpreted as strings.
 
+In addition, the calibration file of the detector specified in the geometry configuration is passed to the EUDAQ2 event decoder using the key `calibration_file` and its canonical path as value.
+
 ### Parameters
 * `file_name`: File name of the EUDAQ2 raw data file. This parameter is mandatory.
 * `inclusive`: Boolean parameter to select whether new data should be compared to the existing Corryvreckan event in inclusive or exclusive mode. The inclusive interpretation will allow new data to be added to the event as soon as there is some overlap between the data time frame and the existing event, i.e. as soon as the end of the time frame is later than the event start or as soon as the time frame start is before the event end. In the exclusive mode, the frame will only be added to the existing event if its start and end are both within the defined event.