Move the Params implementation to CompressorParams

So now CompressorBankParams can just derive Params.

plugins/spectral_compressor/src/compressor_bank.rs

@@ -89,18 +89,23 @@ pub struct ThresholdParams {
     threshold_db: FloatParam,
 }
 
-/// Contains the compressor parameters for both the upwards and downwards compressor banks. This has
+/// Contains the compressor parameters for both the upwards and downwards compressor banks.
-/// a manual `Params` trait implementation to avoid copy-pasting the parameters between the two
+#[derive(Params)]
-/// compressors and making mistakes that way
 pub struct CompressorBankParams {
-    downwards: CompressorParams,
+    #[nested = "downwards"]
-    upwards: CompressorParams,
+    pub downwards: CompressorParams,
+    #[nested = "upwards"]
+    pub upwards: CompressorParams,
 }
 
 /// This struct contains the parameters for either the upward or downward compressors. The `Params`
-/// trait is implemented manually to avoid copy-pasting. Both versions will have a parameter ID and
+/// trait is implemented manually to avoid copy-pasting parameters for both types of compressor.
-/// a parameter name prefix to distinguish them.
+/// Both versions will have a parameter ID and a parameter name prefix to distinguish them.
 pub struct CompressorParams {
+    /// The prefix to use in the `.param_map()` function so the upwards and downwards compressors
+    /// get unique parameter IDs.
+    param_id_prefix: &'static str,
+
     /// The compression threshold relative to the target curve.
     threshold_offset_db: FloatParam,
     /// The compression ratio. At 1.0 the compressor is disengaged.
@@ -115,16 +120,28 @@ pub struct CompressorParams {
     high_freq_ratio_rolloff: FloatParam,
 }
 
-unsafe impl Params for CompressorBankParams {
+unsafe impl Params for CompressorParams {
     fn param_map(&self) -> Vec<(String, ParamPtr, String)> {
-        // The `Params` trait here is implemented manually as an alternative to copy-pasting all of
+        let prefix = self.param_id_prefix;
-        // the parameters and potentially making mistakes
+        vec![
-        let mut param_map = self
+            (
-            .downwards
+                format!("{prefix}threshold_offset"),
-            .param_map_with_prefix("downwards_", "downwards");
+                self.threshold_offset_db.as_ptr(),
-        param_map.append(&mut self.upwards.param_map_with_prefix("upwards_", "upwards"));
+                // The parent `CompressorBankParams` struct will add the group here
-
+                String::new(),
-        param_map
+            ),
+            (format!("{prefix}ratio"), self.ratio.as_ptr(), String::new()),
+            (
+                format!("{prefix}knee"),
+                self.knee_width_db.as_ptr(),
+                String::new(),
+            ),
+            (
+                format!("{prefix}high_freq_rolloff"),
+                self.high_freq_ratio_rolloff.as_ptr(),
+                String::new(),
+            ),
+        ]
     }
 }
 
@@ -201,11 +218,13 @@ impl CompressorBankParams {
     pub fn new(compressor: &CompressorBank) -> Self {
         CompressorBankParams {
             downwards: CompressorParams::new(
+                "downwards_",
                 "Downwards",
                 compressor.should_update_downwards_thresholds.clone(),
                 compressor.should_update_downwards_ratios.clone(),
             ),
             upwards: CompressorParams::new(
+                "upwards_",
                 "Upwards",
                 compressor.should_update_upwards_thresholds.clone(),
                 compressor.should_update_upwards_ratios.clone(),
@@ -219,6 +238,7 @@ impl CompressorParams {
     /// any of the threshold or ratio parameters causes the passed atomics to be updated. These
     /// should be taken from a [`CompressorBank`] so the parameters are linked to it.
     pub fn new(
+        param_id_prefix: &'static str,
         name_prefix: &str,
         should_update_thresholds: Arc<AtomicBool>,
         should_update_ratios: Arc<AtomicBool>,
@@ -229,6 +249,8 @@ impl CompressorParams {
             Arc::new(move |_| should_update_ratios.store(true, Ordering::SeqCst));
 
         CompressorParams {
+            param_id_prefix,
+
             // TODO: Set nicer default values for these things
             // As explained above, these offsets are relative to the target curve
             threshold_offset_db: FloatParam::new(
@@ -277,42 +299,6 @@ impl CompressorParams {
             .with_step_size(0.1),
         }
     }
-
-    /// Create a parameter map for this object with a given prefix and group name.
-    ///
-    /// # Safety
-    ///
-    /// While this function in and of itself it not unsafe (it just creates pointers), these
-    /// pointers can only be safely dereferences and passed to functions that will derefernce them
-    /// if this object is not moved.
-    pub fn param_map_with_prefix(
-        &self,
-        prefix: &str,
-        group: &str,
-    ) -> Vec<(String, ParamPtr, String)> {
-        vec![
-            (
-                format!("{prefix}threshold_offset"),
-                self.threshold_offset_db.as_ptr(),
-                String::from(group),
-            ),
-            (
-                format!("{prefix}ratio"),
-                self.ratio.as_ptr(),
-                String::from(group),
-            ),
-            (
-                format!("{prefix}knee"),
-                self.knee_width_db.as_ptr(),
-                String::from(group),
-            ),
-            (
-                format!("{prefix}high_freq_rolloff"),
-                self.high_freq_ratio_rolloff.as_ptr(),
-                String::from(group),
-            ),
-        ]
-    }
 }
 
 impl CompressorBank {