stream.cc

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// gstreamer
#include "gstreamerJSONFactory.h"
#include "gstreamerConventions.h"
 
// Implementation summary:
// Assemble one frame JSON object incrementally across the frame publish sequence.
 
bool GstreamerJsonFactory::startStreamImpl(const GFrameDataCollection* frameRunData) {
    if (!ofile.is_open()) {
        log->error(gstreamer::ERR_CANTOPENOUTPUT, "%1Error: can't access %2", SFUNCTION_NAME, filename());
    }
    if (!frameRunData) {
        log->error(
            gstreamer::ERR_PUBLISH_ERROR, "frameRunData is null in GstreamerJsonFactory::startStreamImpl");
    }
 
    // Ensure the top-level JSON document is initialized for frame output.
    ensureFileInitializedForType("stream");
 
    // Reset per-frame assembly state.
    is_building_frame = true;
    current_frame.str(std::string());
    current_frame.clear();
    current_frame_has_header  = false;
    current_frame_has_payload = false;
 
    current_frame << "{";
    return true;
}
 
bool GstreamerJsonFactory::endStreamImpl(const GFrameDataCollection* frameRunData) {
    if (!is_building_frame) {
        log->error(
            gstreamer::ERR_PUBLISH_ERROR,
            "endStreamImpl called without an active frame in GstreamerJsonFactory");
        return false;
    }
 
    // Keep the schema predictable even if the caller omitted header or payload publication.
    if (!current_frame_has_header) {
        if (current_frame.str().size() > 1) current_frame << ", ";
        current_frame << "\"header\": {}";
    }
    if (!current_frame_has_payload) {
        if (current_frame.str().size() > 1) current_frame << ", ";
        current_frame << "\"payload\": []";
    }
 
    current_frame << "}";
 
    writeTopLevelEntry(current_frame.str());
 
    is_building_frame = false;
 
    (void)frameRunData;
    return true;
}