DecodeSignal: Re-create SRD session when changes are pending

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

diff --git a/pv/data/decodesignal.cpp b/pv/data/decodesignal.cpp
index 77b2061c6e3b793d554613158761d7707a7af127..95ea45a4e0a707f62fd2b8e6ba259dc4ebd5fc52 100644 (file)
--- a/pv/data/decodesignal.cpp
+++ b/pv/data/decodesignal.cpp
@@ -56,6 +56,7 @@ DecodeSignal::DecodeSignal(pv::Session &session) :
        session_(session),
        srd_session_(nullptr),
        logic_mux_data_invalid_(false),
+       stack_config_changed_(true),
        current_segment_id_(0)
 {
        connect(&session_, SIGNAL(capture_state_changed(int)),
@@ -86,6 +87,7 @@ void DecodeSignal::stack_decoder(const srd_decoder *decoder)
        // Include the newly created decode channels in the channel lists
        update_channel_list();
 
+       stack_config_changed_ = true;
        auto_assign_signals(dec);
        commit_decoder_channels();
        begin_decode();
@@ -105,6 +107,7 @@ void DecodeSignal::remove_decoder(int index)
        stack_.erase(iter);
 
        // Update channels and decoded data
+       stack_config_changed_ = true;
        update_channel_list();
        begin_decode();
 }
@@ -129,6 +132,11 @@ bool DecodeSignal::toggle_decoder_visibility(int index)
 
 void DecodeSignal::reset_decode()
 {
+       if (stack_config_changed_)
+               stop_srd_session();
+       else
+               terminate_srd_session();
+
        if (decode_thread_.joinable()) {
                decode_interrupt_ = true;
                decode_input_cond_.notify_one();
@@ -141,8 +149,6 @@ void DecodeSignal::reset_decode()
                logic_mux_thread_.join();
        }
 
-       stop_srd_session();
-
        class_rows_.clear();
        current_segment_id_ = 0;
        segments_.clear();
@@ -283,6 +289,7 @@ void DecodeSignal::auto_assign_signals(const shared_ptr<Decoder> dec)
 
        if (new_assignment) {
                logic_mux_data_invalid_ = true;
+               stack_config_changed_ = true;
                commit_decoder_channels();
                channels_updated();
        }
@@ -296,6 +303,7 @@ void DecodeSignal::assign_signal(const uint16_t channel_id, const SignalBase *si
                        logic_mux_data_invalid_ = true;
                }
 
+       stack_config_changed_ = true;
        commit_decoder_channels();
        channels_updated();
        begin_decode();
@@ -314,8 +322,8 @@ void DecodeSignal::set_initial_pin_state(const uint16_t channel_id, const int in
                if (ch.id == channel_id)
                        ch.initial_pin_state = init_state;
 
+       stack_config_changed_ = true;
        channels_updated();
-
        begin_decode();
 }
 
@@ -567,6 +575,7 @@ void DecodeSignal::restore_settings(QSettings &settings)
        }
 
        // Update the internal structures
+       stack_config_changed_ = true;
        update_channel_list();
        commit_decoder_channels();
 
@@ -974,14 +983,34 @@ 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_);
@@ -1015,6 +1044,20 @@ void DecodeSignal::start_srd_session()
                DecodeSignal::annotation_callback, this);
 
        srd_session_start(srd_session_);
+
+       // We just recreated the srd session, so all stack changes are applied now
+       stack_config_changed_ = false;
+}
+
+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()