567 lines
24 KiB
Rust
567 lines
24 KiB
Rust
use proc_macro::TokenStream;
|
|
use quote::quote;
|
|
use syn::spanned::Spanned;
|
|
|
|
pub fn derive_params(input: TokenStream) -> TokenStream {
|
|
let ast = syn::parse_macro_input!(input as syn::DeriveInput);
|
|
|
|
let struct_name = &ast.ident;
|
|
let (impl_generics, ty_generics, where_clause) = ast.generics.split_for_impl();
|
|
let fields = match ast.data {
|
|
syn::Data::Struct(syn::DataStruct {
|
|
fields: syn::Fields::Named(named_fields),
|
|
..
|
|
}) => named_fields,
|
|
_ => {
|
|
return syn::Error::new(
|
|
ast.span(),
|
|
"Deriving Params is only supported on structs with named fields",
|
|
)
|
|
.to_compile_error()
|
|
.into()
|
|
}
|
|
};
|
|
|
|
// We only care about fields with `id`, `persist`, and `nested` attributes. For the `id` fields
|
|
// we'll build a mapping function that creates a hashmap containing pointers to those
|
|
// parameters. For the `persist` function we'll create functions that serialize and deserialize
|
|
// those fields individually (so they can be added and removed independently of eachother) using
|
|
// JSON. The `nested` fields should also implement the `Params` trait and their fields will be
|
|
// inherited and added to this field's lists. We'll also enforce that there are no duplicate
|
|
// keys at compile time.
|
|
// TODO: This duplication check doesn't work for nested fields since we don't know anything
|
|
// about the fields on the nested structs
|
|
let mut params: Vec<AnyParam> = Vec::new();
|
|
let mut persistent_fields: Vec<PersistentField> = Vec::new();
|
|
let mut group_params: Vec<NestedParams> = Vec::new();
|
|
for field in fields.named {
|
|
let field_name = match &field.ident {
|
|
Some(ident) => ident,
|
|
_ => continue,
|
|
};
|
|
|
|
// All attributes are mutually exclusive. If we encounter multiple or duplicate attributes,
|
|
// then we'll error out.
|
|
let mut processed_attribute = false;
|
|
for attr in &field.attrs {
|
|
if attr.path.is_ident("id") {
|
|
match attr.parse_meta() {
|
|
Ok(syn::Meta::NameValue(syn::MetaNameValue {
|
|
lit: syn::Lit::Str(s),
|
|
..
|
|
})) => {
|
|
if processed_attribute {
|
|
return syn::Error::new(
|
|
attr.span(),
|
|
"Duplicate or incompatible attribute found",
|
|
)
|
|
.to_compile_error()
|
|
.into();
|
|
}
|
|
|
|
// This is a vector since we want to preserve the order. If structs get
|
|
// large enough to the point where a linear search starts being expensive,
|
|
// then the plugin should probably start splitting up their parameters.
|
|
if params.iter().any(|p| match p {
|
|
AnyParam::Single(param) => param.id == s,
|
|
_ => false,
|
|
}) {
|
|
return syn::Error::new(
|
|
field.span(),
|
|
"Multiple parameters with the same ID found",
|
|
)
|
|
.to_compile_error()
|
|
.into();
|
|
}
|
|
|
|
params.push(AnyParam::Single(Param {
|
|
id: s,
|
|
field: field_name.clone(),
|
|
}));
|
|
|
|
processed_attribute = true;
|
|
}
|
|
_ => {
|
|
return syn::Error::new(
|
|
attr.span(),
|
|
"The id attribute should be a key-value pair with a string argument: \
|
|
#[id = \"foo_bar\"]",
|
|
)
|
|
.to_compile_error()
|
|
.into()
|
|
}
|
|
};
|
|
} else if attr.path.is_ident("persist") {
|
|
match attr.parse_meta() {
|
|
Ok(syn::Meta::NameValue(syn::MetaNameValue {
|
|
lit: syn::Lit::Str(s),
|
|
..
|
|
})) => {
|
|
if processed_attribute {
|
|
return syn::Error::new(
|
|
attr.span(),
|
|
"Duplicate or incompatible attribute found",
|
|
)
|
|
.to_compile_error()
|
|
.into();
|
|
}
|
|
|
|
if persistent_fields.iter().any(|p| p.key == s) {
|
|
return syn::Error::new(
|
|
field.span(),
|
|
"Multiple persistent fields with the same key found",
|
|
)
|
|
.to_compile_error()
|
|
.into();
|
|
}
|
|
|
|
persistent_fields.push(PersistentField {
|
|
key: s,
|
|
field: field_name.clone(),
|
|
});
|
|
|
|
processed_attribute = true;
|
|
}
|
|
_ => {
|
|
return syn::Error::new(
|
|
attr.span(),
|
|
"The persist attribute should be a key-value pair with a string \
|
|
argument: #[persist = \"foo_bar\"]",
|
|
)
|
|
.to_compile_error()
|
|
.into()
|
|
}
|
|
};
|
|
} else if attr.path.is_ident("nested") {
|
|
// This one is more complicated. Support an `array` attribute, an `id_prefix =
|
|
// "foo"` attribute, and a `group = "group name"` attribute. All are optional, and
|
|
// the first two are mutually exclusive.
|
|
let mut nested_array = false;
|
|
let mut nested_id_prefix: Option<syn::LitStr> = None;
|
|
let mut nested_group: Option<syn::LitStr> = None;
|
|
match attr.parse_meta() {
|
|
Ok(syn::Meta::List(syn::MetaList {
|
|
nested: nested_attrs,
|
|
..
|
|
})) => {
|
|
if processed_attribute {
|
|
return syn::Error::new(
|
|
attr.span(),
|
|
"Duplicate or incompatible attribute found",
|
|
)
|
|
.to_compile_error()
|
|
.into();
|
|
}
|
|
|
|
for nested_attr in nested_attrs {
|
|
match nested_attr {
|
|
syn::NestedMeta::Meta(syn::Meta::Path(p))
|
|
if p.is_ident("array") =>
|
|
{
|
|
nested_array = true;
|
|
}
|
|
syn::NestedMeta::Meta(syn::Meta::NameValue(
|
|
syn::MetaNameValue {
|
|
path,
|
|
lit: syn::Lit::Str(s),
|
|
..
|
|
},
|
|
)) if path.is_ident("id_prefix") => {
|
|
nested_id_prefix = Some(s.clone());
|
|
}
|
|
syn::NestedMeta::Meta(syn::Meta::NameValue(
|
|
syn::MetaNameValue {
|
|
path,
|
|
lit: syn::Lit::Str(s),
|
|
..
|
|
},
|
|
)) if path.is_ident("group") => {
|
|
let group_name = s.value();
|
|
if group_name.is_empty() {
|
|
return syn::Error::new(
|
|
attr.span(),
|
|
"Group names cannot be empty",
|
|
)
|
|
.to_compile_error()
|
|
.into();
|
|
} else if group_name.contains('/') {
|
|
return syn::Error::new(
|
|
attr.span(),
|
|
"Group names may not contain slashes",
|
|
)
|
|
.to_compile_error()
|
|
.into();
|
|
} else {
|
|
nested_group = Some(s.clone());
|
|
}
|
|
}
|
|
_ => {
|
|
return syn::Error::new(
|
|
nested_attr.span(),
|
|
"Unknown attribute. See the Params trait documentation \
|
|
for more information.",
|
|
)
|
|
.to_compile_error()
|
|
.into()
|
|
}
|
|
}
|
|
}
|
|
|
|
let param = match (nested_array, nested_id_prefix) {
|
|
(true, None) => NestedParams::Array {
|
|
field: field_name.clone(),
|
|
group: nested_group,
|
|
},
|
|
(false, Some(id_prefix)) => NestedParams::Prefixed {
|
|
field: field_name.clone(),
|
|
id_prefix,
|
|
group: nested_group,
|
|
},
|
|
(false, None) => NestedParams::Inline {
|
|
field: field_name.clone(),
|
|
group: nested_group,
|
|
},
|
|
(true, Some(_)) => {
|
|
return syn::Error::new(
|
|
attr.span(),
|
|
"'array' cannot be used together with 'id_prefix'",
|
|
)
|
|
.to_compile_error()
|
|
.into()
|
|
}
|
|
};
|
|
|
|
// Grouped parameters are handled differently than nested parameters:
|
|
// DAWs that support grouped parameters usually display parameter groups below "regular" ones
|
|
// in a tree view. To keep the order consistent with those, group parameters are collected
|
|
// separately, so they can be inserted at the end of the parameter list.
|
|
// Nested parameters without a group on the other hand are merely an implementation detail of
|
|
// the plugin and thus should not behave different than regular parameters to the user. Because
|
|
// of this, they are inserted alongside the "regular" ones.
|
|
if param.is_group() {
|
|
group_params.push(param);
|
|
} else {
|
|
params.push(AnyParam::Nested(param));
|
|
}
|
|
|
|
processed_attribute = true;
|
|
}
|
|
_ => {
|
|
return syn::Error::new(
|
|
attr.span(),
|
|
"The nested attribute should be a list in the following format: \
|
|
#[nested([array | id_prefix = \"foo\"], [group = \"group name\"])]",
|
|
)
|
|
.to_compile_error()
|
|
.into()
|
|
}
|
|
};
|
|
}
|
|
}
|
|
}
|
|
|
|
// The next step is build the gathered information into tokens that can be spliced into a
|
|
// `Params` implementation
|
|
let param_map_tokens = {
|
|
let param_mapping_self_tokens = params.into_iter().map(|p| p.to_token());
|
|
let param_mapping_group_tokens = group_params.iter().map(|p| p.to_token());
|
|
|
|
quote! {
|
|
// This may not be in scope otherwise, used to call .as_ptr()
|
|
use ::nih_plug::params::Param;
|
|
|
|
#[allow(unused_mut)]
|
|
let mut param_map = Vec::new();
|
|
#(param_map.extend(#param_mapping_self_tokens); )*
|
|
#(param_map.extend(#param_mapping_group_tokens); )*
|
|
|
|
param_map
|
|
}
|
|
};
|
|
|
|
let (serialize_fields_tokens, deserialize_fields_tokens) = {
|
|
// Like with `param_map()`, we'll try to do the serialization for this struct and then
|
|
// recursively call the child parameter structs. We don't know anything about the actual
|
|
// field types, but because we can generate this function we can get type erasure for free
|
|
// since we only need to worry about byte vectors.
|
|
let (serialize_fields_self_tokens, deserialize_fields_match_self_tokens): (Vec<_>, Vec<_>) =
|
|
persistent_fields
|
|
.into_iter()
|
|
.map(|PersistentField { field, key }| {
|
|
(
|
|
quote! {
|
|
match ::nih_plug::params::persist::PersistentField::map(
|
|
&self.#field,
|
|
::nih_plug::params::persist::serialize_field,
|
|
) {
|
|
Ok(data) => {
|
|
serialized.insert(String::from(#key), data);
|
|
}
|
|
Err(err) => {
|
|
::nih_plug::nih_debug_assert_failure!(
|
|
"Could not serialize '{}': {}",
|
|
#key,
|
|
err
|
|
)
|
|
}
|
|
};
|
|
},
|
|
quote! {
|
|
#key => {
|
|
match ::nih_plug::params::persist::deserialize_field(&data) {
|
|
Ok(deserialized) => {
|
|
::nih_plug::params::persist::PersistentField::set(
|
|
&self.#field,
|
|
deserialized,
|
|
);
|
|
}
|
|
Err(err) => {
|
|
::nih_plug::nih_debug_assert_failure!(
|
|
"Could not deserialize '{}': {}",
|
|
#key,
|
|
err
|
|
)
|
|
}
|
|
};
|
|
}
|
|
},
|
|
)
|
|
})
|
|
.unzip();
|
|
|
|
let (serialize_fields_nested_tokens, deserialize_fields_nested_tokens): (Vec<_>, Vec<_>) =
|
|
group_params
|
|
.iter()
|
|
.map(|nested| match nested {
|
|
NestedParams::Inline { field, .. } | NestedParams::Prefixed { field, .. } => (
|
|
// TODO: For some reason the macro won't parse correctly if you inline this
|
|
quote! {
|
|
let inlineme = self.#field.serialize_fields();
|
|
serialized.extend(inlineme);
|
|
},
|
|
quote! { self.#field.deserialize_fields(serialized) },
|
|
),
|
|
NestedParams::Array { field, .. } => (
|
|
quote! {
|
|
for field in self.#field.iter() {
|
|
serialized.extend(field.serialize_fields());
|
|
}
|
|
},
|
|
quote! {
|
|
for field in self.#field.iter() {
|
|
field.deserialize_fields(serialized);
|
|
}
|
|
},
|
|
),
|
|
})
|
|
.unzip();
|
|
|
|
let serialize_fields_tokens = quote! {
|
|
#[allow(unused_mut)]
|
|
let mut serialized = ::std::collections::BTreeMap::new();
|
|
#(#serialize_fields_self_tokens);*
|
|
|
|
#(#serialize_fields_nested_tokens);*
|
|
|
|
serialized
|
|
};
|
|
|
|
let deserialize_fields_tokens = quote! {
|
|
for (field_name, data) in serialized {
|
|
match field_name.as_str() {
|
|
#(#deserialize_fields_match_self_tokens)*
|
|
_ => ::nih_plug::nih_debug_assert_failure!("Unknown serialized field name: {} (this may not be accurate)", field_name),
|
|
}
|
|
}
|
|
|
|
// FIXME: The above warning will course give false postiives when using nested
|
|
// parameter structs. An easy fix would be to use
|
|
// https://doc.rust-lang.org/std/collections/struct.HashMap.html#method.drain_filter
|
|
// once that gets stabilized.
|
|
#(#deserialize_fields_nested_tokens);*
|
|
};
|
|
|
|
(serialize_fields_tokens, deserialize_fields_tokens)
|
|
};
|
|
|
|
quote! {
|
|
unsafe impl #impl_generics Params for #struct_name #ty_generics #where_clause {
|
|
fn param_map(&self) -> Vec<(String, nih_plug::prelude::ParamPtr, String)> {
|
|
#param_map_tokens
|
|
}
|
|
|
|
fn serialize_fields(&self) -> ::std::collections::BTreeMap<String, String> {
|
|
#serialize_fields_tokens
|
|
}
|
|
|
|
fn deserialize_fields(&self, serialized: &::std::collections::BTreeMap<String, String>) {
|
|
#deserialize_fields_tokens
|
|
}
|
|
}
|
|
}
|
|
.into()
|
|
}
|
|
|
|
#[derive(Debug)]
|
|
enum AnyParam {
|
|
Single(Param),
|
|
Nested(NestedParams),
|
|
}
|
|
|
|
impl AnyParam {
|
|
fn to_token(&self) -> proc_macro2::TokenStream {
|
|
match self {
|
|
AnyParam::Single(Param { field, id }) => {
|
|
quote! { [(String::from(#id), self.#field.as_ptr(), String::new())] }
|
|
}
|
|
AnyParam::Nested(params) => params.to_token(),
|
|
}
|
|
}
|
|
}
|
|
|
|
/// A parameter that should be added to the parameter map.
|
|
#[derive(Debug)]
|
|
struct Param {
|
|
/// The name of the parameter's field on the struct.
|
|
field: syn::Ident,
|
|
/// The parameter's unique ID.
|
|
id: syn::LitStr,
|
|
}
|
|
|
|
/// A field containing data that must be stored in the plugin's state.
|
|
#[derive(Debug)]
|
|
struct PersistentField {
|
|
/// The name of the field on the struct.
|
|
field: syn::Ident,
|
|
/// The field's unique key.
|
|
key: syn::LitStr,
|
|
}
|
|
|
|
/// A field containing another object whose parameters and persistent fields should be added to this
|
|
/// struct's.
|
|
#[derive(Debug)]
|
|
enum NestedParams {
|
|
/// The nested struct's parameters are taken as is.
|
|
Inline {
|
|
field: syn::Ident,
|
|
group: Option<syn::LitStr>,
|
|
},
|
|
/// The nested struct's parameters will get an ID prefix. The original parmaeter with ID `foo`
|
|
/// will become `{id_prefix}_foo`.
|
|
Prefixed {
|
|
field: syn::Ident,
|
|
id_prefix: syn::LitStr,
|
|
group: Option<syn::LitStr>,
|
|
},
|
|
/// This field is an array-like data structure containing nested parameter structs. The
|
|
/// parameter `foo` will get the new parameter ID `foo_{array_idx + 1}`, and if the group name
|
|
/// is set then the group will be `{group_name} {array_idx + 1}`.
|
|
Array {
|
|
field: syn::Ident,
|
|
group: Option<syn::LitStr>,
|
|
},
|
|
}
|
|
|
|
impl NestedParams {
|
|
fn is_group(&self) -> bool {
|
|
let group = match self {
|
|
NestedParams::Inline { field: _, group } => group,
|
|
NestedParams::Prefixed {
|
|
field: _,
|
|
id_prefix: _,
|
|
group,
|
|
} => group,
|
|
NestedParams::Array { field: _, group } => group,
|
|
};
|
|
|
|
group.is_some()
|
|
}
|
|
|
|
fn to_token(&self) -> proc_macro2::TokenStream {
|
|
// How nested parameters are handled depends on the `NestedParams` variant.
|
|
// These are pairs of `(parameter_id, param_ptr, param_group)`. The specific
|
|
// parameter types know how to convert themselves into the correct ParamPtr variant.
|
|
// Top-level parameters have no group, and we'll prefix the group name specified in
|
|
// the `#[nested(...)]` attribute to fields coming from nested groups
|
|
|
|
match self {
|
|
// TODO: No idea how to splice this as an `Option<&str>`, so this involves some
|
|
// copy-pasting
|
|
NestedParams::Inline {
|
|
field,
|
|
group: Some(group),
|
|
} => quote! {
|
|
self.#field.param_map().into_iter().map(|(param_id, param_ptr, nested_group_name)| {
|
|
if nested_group_name.is_empty() {
|
|
(param_id, param_ptr, String::from(#group))
|
|
} else {
|
|
(param_id, param_ptr, format!("{}/{}", #group, nested_group_name))
|
|
}
|
|
})
|
|
},
|
|
NestedParams::Inline { field, group: None } => quote! {
|
|
self.#field.param_map();
|
|
},
|
|
NestedParams::Prefixed {
|
|
field,
|
|
id_prefix,
|
|
group: Some(group),
|
|
} => quote! {
|
|
self.#field.param_map().into_iter().map(|(param_id, param_ptr, nested_group_name)| {
|
|
let param_id = format!("{}_{}", #id_prefix, param_id);
|
|
|
|
if nested_group_name.is_empty() {
|
|
(param_id, param_ptr, String::from(#group))
|
|
} else {
|
|
(param_id, param_ptr, format!("{}/{}", #group, nested_group_name))
|
|
}
|
|
})
|
|
},
|
|
NestedParams::Prefixed {
|
|
field,
|
|
id_prefix,
|
|
group: None,
|
|
} => quote! {
|
|
self.#field.param_map().into_iter().map(|(param_id, param_ptr, nested_group_name)| {
|
|
let param_id = format!("{}_{}", #id_prefix, param_id);
|
|
|
|
(param_id, param_ptr, nested_group_name)
|
|
})
|
|
},
|
|
// We'll start at index 1 for display purposes. Both the group and the parameter ID get
|
|
// a suffix matching the array index.
|
|
NestedParams::Array {
|
|
field,
|
|
group: Some(group),
|
|
} => quote! {
|
|
self.#field.iter().enumerate().flat_map(|(idx, params)| {
|
|
let idx = idx + 1;
|
|
|
|
params.param_map().into_iter().map(move |(param_id, param_ptr, nested_group_name)| {
|
|
let param_id = format!("{}_{}", param_id, idx);
|
|
let group = format!("{} {}", #group, idx);
|
|
|
|
// Note that this is different from the other variants
|
|
if nested_group_name.is_empty() {
|
|
(param_id, param_ptr, group)
|
|
} else {
|
|
(param_id, param_ptr, format!("{}/{}", group, nested_group_name))
|
|
}
|
|
})
|
|
})
|
|
},
|
|
NestedParams::Array { field, group: None } => quote! {
|
|
self.#field.iter().enumerate().flat_map(|(idx, params)| {
|
|
let idx = idx + 1;
|
|
|
|
params.param_map().into_iter().map(move |(param_id, param_ptr, nested_group_name)| {
|
|
let param_id = format!("{}_{}", param_id, idx);
|
|
|
|
(param_id, param_ptr, nested_group_name)
|
|
})
|
|
})
|
|
},
|
|
}
|
|
}
|
|
}
|