Add a way to find out the current plugin API

src/context.rs

@@ -1,5 +1,7 @@
 //! Different contexts the plugin can use to make callbacks to the host in different...contexts.
 
+use std::fmt::Display;
+
 use crate::midi::NoteEvent;
 use crate::param::internals::ParamPtr;
 use crate::param::Param;
@@ -16,6 +18,9 @@ use crate::wrapper::state::PluginState;
 // The implementing wrapper needs to be able to handle concurrent requests, and it should perform
 // the actual callback within [MainThreadQueue::do_maybe_async].
 pub trait ProcessContext {
+    /// Get the current plugin API.
+    fn plugin_api(&self) -> PluginApi;
+
     /// Get information about the current transport position and status.
     fn transport(&self) -> &Transport;
 
@@ -77,6 +82,10 @@ pub trait ProcessContext {
 // The implementing wrapper can assume that everything is being called from the main thread. Since
 // NIH-plug doesn't own the GUI event loop, this invariant cannot be part of the interface.
 pub trait GuiContext: Send + Sync + 'static {
+    /// Get the current plugin API. This may be useful to display in the plugin's GUI as part of an
+    /// about screen.
+    fn plugin_api(&self) -> PluginApi;
+
     /// Ask the host to resize the editor window to the size specified by
     /// [`Editor::size()`][crate::prelude::Editor::size()]. This will return false if the host
     /// somehow didn't like this and rejected the resize, in which case the window should revert to
@@ -186,6 +195,23 @@ pub struct ParamSetter<'a> {
     pub raw_context: &'a dyn GuiContext,
 }
 
+/// The currently active plugin API. This may be useful to display in an about screen in the
+/// plugin's GUI for debugging purposes.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum PluginApi {
+    Clap,
+    Vst3,
+}
+
+impl Display for PluginApi {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            PluginApi::Clap => write!(f, "CLAP"),
+            PluginApi::Vst3 => write!(f, "VST3"),
+        }
+    }
+}
+
 // TODO: These conversions have not really been tested yet, there might be an error in there somewhere
 impl Transport {
     /// Initialize the transport struct without any information.

src/prelude.rs

@@ -13,7 +13,7 @@ pub use crate::formatters;
 pub use crate::util;
 
 pub use crate::buffer::Buffer;
-pub use crate::context::{GuiContext, ParamSetter, ProcessContext};
+pub use crate::context::{GuiContext, ParamSetter, PluginApi, ProcessContext};
 // This also includes the derive macro
 pub use crate::midi::{control_change, MidiConfig, NoteEvent};
 pub use crate::param::enums::{Enum, EnumParam};

src/wrapper/clap/context.rs

@@ -4,7 +4,7 @@ use std::sync::atomic::Ordering;
 use std::sync::Arc;
 
 use super::wrapper::{OutputParamEvent, Task, Wrapper};
-use crate::context::{GuiContext, ProcessContext, Transport};
+use crate::context::{GuiContext, PluginApi, ProcessContext, Transport};
 use crate::event_loop::EventLoop;
 use crate::midi::NoteEvent;
 use crate::param::internals::ParamPtr;
@@ -28,6 +28,10 @@ pub(crate) struct WrapperProcessContext<'a, P: ClapPlugin> {
 }
 
 impl<P: ClapPlugin> GuiContext for WrapperGuiContext<P> {
+    fn plugin_api(&self) -> PluginApi {
+        PluginApi::Clap
+    }
+
     fn request_resize(&self) -> bool {
         self.wrapper.request_resize()
     }
@@ -92,6 +96,10 @@ impl<P: ClapPlugin> GuiContext for WrapperGuiContext<P> {
 }
 
 impl<P: ClapPlugin> ProcessContext for WrapperProcessContext<'_, P> {
+    fn plugin_api(&self) -> PluginApi {
+        PluginApi::Clap
+    }
+
     fn transport(&self) -> &Transport {
         &self.transport
     }

src/wrapper/vst3/context.rs

@@ -5,7 +5,7 @@ use std::sync::Arc;
 use vst3_sys::vst::{IComponentHandler, RestartFlags};
 
 use super::inner::{Task, WrapperInner};
-use crate::context::{GuiContext, ProcessContext, Transport};
+use crate::context::{GuiContext, PluginApi, ProcessContext, Transport};
 use crate::midi::NoteEvent;
 use crate::param::internals::ParamPtr;
 use crate::plugin::Vst3Plugin;
@@ -29,6 +29,10 @@ pub(crate) struct WrapperProcessContext<'a, P: Vst3Plugin> {
 }
 
 impl<P: Vst3Plugin> GuiContext for WrapperGuiContext<P> {
+    fn plugin_api(&self) -> PluginApi {
+        PluginApi::Vst3
+    }
+
     fn request_resize(&self) -> bool {
         let task_posted = self.inner.do_maybe_async(Task::RequestResize);
         nih_debug_assert!(task_posted, "The task queue is full, dropping task...");
@@ -102,6 +106,10 @@ impl<P: Vst3Plugin> GuiContext for WrapperGuiContext<P> {
 }
 
 impl<P: Vst3Plugin> ProcessContext for WrapperProcessContext<'_, P> {
+    fn plugin_api(&self) -> PluginApi {
+        PluginApi::Vst3
+    }
+
     fn transport(&self) -> &Transport {
         &self.transport
     }