DecodeSignal: Reset and re-use existing decoder sessions

[pulseview.git] / pv / data / decodesignal.cpp

diff --git a/pv/data/decodesignal.cpp b/pv/data/decodesignal.cpp
index 77b2061c6e3b793d554613158761d7707a7af127..df385be8d99ce397ed9aba327247f37e0176983b 100644 (file)
--- a/pv/data/decodesignal.cpp
+++ b/pv/data/decodesignal.cpp
@@ -129,6 +129,8 @@ bool DecodeSignal::toggle_decoder_visibility(int index)
 
 void DecodeSignal::reset_decode()
 {
+       terminate_srd_session();
+
        if (decode_thread_.joinable()) {
                decode_interrupt_ = true;
                decode_input_cond_.notify_one();
@@ -157,6 +159,8 @@ void DecodeSignal::reset_decode()
 
 void DecodeSignal::begin_decode()
 {
+       terminate_srd_session();
+
        if (decode_thread_.joinable()) {
                decode_interrupt_ = true;
                decode_input_cond_.notify_one();
@@ -974,14 +978,34 @@ void DecodeSignal::decode_proc()
                        }
                }
        } while (error_message_.isEmpty() && !decode_interrupt_);
+
+       // Potentially reap decoders when the application no longer is
+       // interested in their (pending) results.
+       if (decode_interrupt_)
+               terminate_srd_session();
 }
 
 void DecodeSignal::start_srd_session()
 {
        uint64_t samplerate;
 
-       if (srd_session_)
-               stop_srd_session();
+       if (srd_session_) {
+               // When a decoder stack was created before, re-use it
+               // for the next stream of input data, after terminating
+               // potentially still executing operations, and resetting
+               // internal state. Skip the rather expensive (teardown
+               // and) construction of another decoder stack.
+
+               // TODO Reduce redundancy, use a common code path for
+               // the meta/cb/start sequence?
+               terminate_srd_session();
+               srd_session_metadata_set(srd_session_, SRD_CONF_SAMPLERATE,
+                       g_variant_new_uint64(segments_.at(current_segment_id_).samplerate));
+               srd_pd_output_callback_add(srd_session_, SRD_OUTPUT_ANN,
+                       DecodeSignal::annotation_callback, this);
+               srd_session_start(srd_session_);
+               return;
+       }
 
        // Create the session
        srd_session_new(&srd_session_);
@@ -1017,6 +1041,17 @@ void DecodeSignal::start_srd_session()
        srd_session_start(srd_session_);
 }
 
+void DecodeSignal::terminate_srd_session()
+{
+       // Call the "terminate and reset" routine for the decoder stack
+       // (if available). This does not harm those stacks which already
+       // have completed their operation, and reduces response time for
+       // those stacks which still are processing data while the
+       // application no longer wants them to.
+       if (srd_session_)
+               srd_session_terminate_reset(srd_session_);
+}
+
 void DecodeSignal::stop_srd_session()
 {
        if (srd_session_) {