handling sample loading errors gracefully

src/matrix.rs

@@ -597,6 +597,10 @@ impl Matrix {
         }
     }
 
+    pub fn pop_error(&mut self) -> Option<String> {
+        self.config.pop_error()
+    }
+
     /// Assign [SAtom] values to input parameters and atoms.
     pub fn set_param(&mut self, param: ParamId, at: SAtom) {
         self.config.set_param(param, at);

src/nodes/node_conf.rs

@@ -147,6 +147,9 @@ pub struct NodeConfigurator {
     /// for nodes.
     sample_lib:                    SampleLibrary,
 
+    /// Error messages:
+    errors:         Vec<String>,
+
     /// Contains (automateable) parameters
     params:         std::collections::HashMap<ParamId, NodeInputParam>,
     /// Stores the most recently set parameter values
@@ -231,6 +234,7 @@ impl NodeConfigurator {
         (NodeConfigurator {
             nodes,
             shared,
+            errors:             vec![],
             sample_lib:         SampleLibrary::new(),
             feedback_filter:    FeedbackFilter::new(),
             output_fb_values:   vec![],
@@ -277,6 +281,10 @@ impl NodeConfigurator {
         }
     }
 
+    pub fn pop_error(&mut self) -> Option<String> {
+        self.errors.pop()
+    }
+
     pub fn unique_index_for(&self, ni: &NodeId) -> Option<usize> {
         self.node2idx.get(&ni).copied()
     }
@@ -299,8 +307,17 @@ impl NodeConfigurator {
     pub fn set_param(&mut self, param: ParamId, at: SAtom) {
         if param.is_atom() {
             let at =
-                if let SAtom::AudioSample((path, None)) = at {
-                    self.sample_lib.load(&path).unwrap().clone()
+                if let SAtom::AudioSample((path, None)) = at.clone() {
+                    match self.sample_lib.load(&path) {
+                        Ok(sample) => sample.clone(),
+                        Err(e) => {
+                            self.errors.push(
+                                format!(
+                                    "Couldn't load sample '{}': {:?}",
+                                    path, e));
+                            at
+                        },
+                    }
                 } else {
                     at
                 };

tests/basics.rs

@@ -1199,3 +1199,29 @@ fn check_node_sampl_reload() {
         assert_eq!(fft[0], (441, 940));
     }
 }
+
+#[test]
+fn check_node_sampl_load_err() {
+    let (node_conf, mut node_exec) = new_node_engine();
+    let mut matrix = Matrix::new(node_conf, 3, 3);
+
+    let smpl = NodeId::Sampl(0);
+    let out  = NodeId::Out(0);
+    matrix.place(0, 0, Cell::empty(smpl)
+                       .out(None, None, smpl.out("sig")));
+    matrix.place(0, 1, Cell::empty(out)
+                       .input(out.inp("ch1"), None, None));
+    matrix.sync().unwrap();
+
+    let sample_p = smpl.inp_param("sample").unwrap();
+    let freq_p   = smpl.inp_param("freq").unwrap();
+    matrix.set_param(sample_p, SAtom::audio_unloaded("tests/sample_NOSIN.wav"));
+
+    let (rms, min, max) = run_and_get_l_rms_mimax(&mut node_exec, 50.0);
+    assert_float_eq!(rms, 0.0);
+    assert_float_eq!(min, 0.0);
+    assert_float_eq!(max, 0.0);
+
+    let err = matrix.pop_error();
+    assert_eq!(err.unwrap(), "Couldn't load sample 'tests/sample_NOSIN.wav': LoadError(IoError(Os { code: 2, kind: NotFound, message: \"No such file or directory\" }))");
+}