Simple CLAP undo extension support

Call change_made() whenever we call mark_dirty()
Seems to fix undo behavior in Bitwig at least

Author: ilmai

plinth-plugin/src/formats/clap/extensions/gui.rs

@@ -92,6 +92,7 @@ impl<P: ClapPlugin> Gui<P> {
                 instance.host_ext_gui,
                 instance.host_ext_params,
                 instance.host_ext_state,
+                instance.host_ext_undo,
                 instance.parameter_event_map.clone(),
             ));
 

plinth-plugin/src/formats/clap/host.rs

@@ -1,6 +1,6 @@
-use std::{sync::{atomic::Ordering, Arc}};
+use std::{ptr::null, sync::{Arc, atomic::Ordering}};
 
-use clap_sys::{ext::{gui::clap_host_gui, params::clap_host_params, state::clap_host_state}, host::clap_host};
+use clap_sys::{ext::{draft::undo::clap_host_undo, gui::clap_host_gui, params::clap_host_params, state::clap_host_state}, host::clap_host};
 
 use crate::{Host, ParameterId, ParameterValue};
 
@@ -11,6 +11,7 @@ pub struct ClapHost {
     host_ext_gui: *const clap_host_gui,
     host_ext_params: *const clap_host_params,
     host_ext_state: *const clap_host_state,
+    host_ext_undo: *const clap_host_undo,
     parameter_event_map: Arc<ParameterEventMap>,
 }
 
@@ -20,6 +21,7 @@ impl ClapHost {
         host_ext_gui: *const clap_host_gui,
         host_ext_params: *const clap_host_params,
         host_ext_state: *const clap_host_state,
+        host_ext_undo: *const clap_host_undo,
         parameter_event_map: Arc<ParameterEventMap>,
     ) -> Self {
         assert!(!raw.is_null());
@@ -29,6 +31,7 @@ impl ClapHost {
             host_ext_gui,
             host_ext_params,
             host_ext_state,
+            host_ext_undo,
             parameter_event_map,
         }
     }
@@ -49,7 +52,7 @@ impl Host for ClapHost {
 
     fn start_parameter_change(&self, id: ParameterId) {
         self.parameter_event_map.parameter_event_info(id).change_started.store(true, Ordering::Release);
-        
+
         if !self.host_ext_params.is_null() {
             unsafe { ((*self.host_ext_params).request_flush.unwrap())(self.raw) };
         }
@@ -73,17 +76,29 @@ impl Host for ClapHost {
             unsafe { ((*self.host_ext_params).request_flush.unwrap())(self.raw) };
         }
     }
-    
+
     fn reload_parameters(&self) {
         if !self.host_ext_params.is_null() {
             unsafe { ((*self.host_ext_params).request_flush.unwrap())(self.raw) };
-        }        
+        }
     }
 
     fn mark_state_dirty(&self) {
         if !self.host_ext_state.is_null() {
             unsafe { ((*self.host_ext_state).mark_dirty.unwrap())(self.raw) };
         }
+
+        if !self.host_ext_undo.is_null() {
+            unsafe {
+                ((*self.host_ext_undo).change_made.unwrap())(
+                    self.raw,
+                    c"".as_ptr(),
+                    null(),
+                    0,
+                    false,
+                )
+            };
+        }
     }
 }
 

plinth-plugin/src/formats/clap/plugin_instance.rs

@@ -1,7 +1,7 @@
 use std::{collections::BTreeMap, ffi::{CStr, c_char, c_void}, iter::zip, ptr::{null, null_mut}, sync::{Arc, atomic::{AtomicBool, AtomicUsize, Ordering}}};
 
 use atomic_refcell::AtomicRefCell;
-use clap_sys::{events::clap_input_events, ext::{audio_ports::CLAP_EXT_AUDIO_PORTS, gui::{clap_host_gui, CLAP_EXT_GUI}, latency::CLAP_EXT_LATENCY, note_ports::CLAP_EXT_NOTE_PORTS, params::{clap_host_params, CLAP_EXT_PARAMS}, render::CLAP_EXT_RENDER, state::{clap_host_state, CLAP_EXT_STATE}, tail::{clap_host_tail, CLAP_EXT_TAIL}, timer_support::{clap_host_timer_support, CLAP_EXT_TIMER_SUPPORT}}, host::clap_host, plugin::clap_plugin, process::{clap_process, clap_process_status, CLAP_PROCESS_CONTINUE, CLAP_PROCESS_CONTINUE_IF_NOT_QUIET, CLAP_PROCESS_ERROR, CLAP_PROCESS_TAIL}};
+use clap_sys::{events::clap_input_events, ext::{audio_ports::CLAP_EXT_AUDIO_PORTS, draft::undo::{CLAP_EXT_UNDO, clap_host_undo}, gui::{CLAP_EXT_GUI, clap_host_gui}, latency::CLAP_EXT_LATENCY, note_ports::CLAP_EXT_NOTE_PORTS, params::{CLAP_EXT_PARAMS, clap_host_params}, render::CLAP_EXT_RENDER, state::{CLAP_EXT_STATE, clap_host_state}, tail::{CLAP_EXT_TAIL, clap_host_tail}, timer_support::{CLAP_EXT_TIMER_SUPPORT, clap_host_timer_support}}, host::clap_host, plugin::clap_plugin, process::{CLAP_PROCESS_CONTINUE, CLAP_PROCESS_CONTINUE_IF_NOT_QUIET, CLAP_PROCESS_ERROR, CLAP_PROCESS_TAIL, clap_process, clap_process_status}};
 use tracing::error;
 use plinth_core::signals::{ptr_signal::{PtrSignal, PtrSignalMut}, signal::SignalMut};
 use raw_window_handle::RawWindowHandle;
@@ -59,6 +59,7 @@ pub struct PluginInstance<P: ClapPlugin> {
     pub(super) host_ext_state: *const clap_host_state,
     host_ext_tail: *const clap_host_tail,
     pub(super) host_ext_timer_support: *const clap_host_timer_support,
+    pub(super) host_ext_undo: *const clap_host_undo,
 }
 
 impl<P: ClapPlugin> PluginInstance<P> {
@@ -148,6 +149,7 @@ impl<P: ClapPlugin> PluginInstance<P> {
             host_ext_state: null(),
             host_ext_tail: null(),
             host_ext_timer_support: null(),
+            host_ext_undo: null(),
         }
     }
 
@@ -193,6 +195,7 @@ impl<P: ClapPlugin> PluginInstance<P> {
             instance.host_ext_state = unsafe { ((*instance.host).get_extension.unwrap())(instance.host, CLAP_EXT_STATE.as_ptr()) as _ };
             instance.host_ext_tail = unsafe { ((*instance.host).get_extension.unwrap())(instance.host, CLAP_EXT_TAIL.as_ptr()) as _ };
             instance.host_ext_timer_support = unsafe { ((*instance.host).get_extension.unwrap())(instance.host, CLAP_EXT_TIMER_SUPPORT.as_ptr()) as _ };
+            instance.host_ext_undo = unsafe { ((*instance.host).get_extension.unwrap())(instance.host, CLAP_EXT_UNDO.as_ptr()) as _ };
 
             instance.plugin.as_mut().unwrap().init();
         });