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Split up the nih_plug_derive crate into modules

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This commit is contained in:
Robbert van der Helm 2022-03-16 15:53:25 +01:00
parent 21ce38ca23
commit 6628baf47e
5 changed files with 373 additions and 362 deletions
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99
nih_plug_derive/src/enums.rs Normal file
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@ -0,0 +1,99 @@
use proc_macro::TokenStream;
use quote::quote;
use syn::spanned::Spanned;
pub fn derive_enum(input: TokenStream) -> TokenStream {
let ast = syn::parse_macro_input!(input as syn::DeriveInput);
let struct_name = &ast.ident;
let variants = match ast.data {
// syn::Data::Struct(syn::DataStruct {
// fields: syn::Fields::Named(named_fields),
// ..
// }) => named_fields,
syn::Data::Enum(syn::DataEnum { variants, .. }) => variants,
_ => {
return syn::Error::new(ast.span(), "Deriving Enum is only supported on enums")
.to_compile_error()
.into()
}
};
// The `Enum` trait is super simple: variant names are mapped to their index in the declaration
// order, and the names are either just the variant name or a `#[name = "..."]` attribute in
// case the name should contain a space.
let mut variant_names = Vec::new();
let mut to_index_tokens = Vec::new();
let mut from_index_tokens = Vec::new();
for (variant_idx, variant) in variants.iter().enumerate() {
if !variant.fields.is_empty() {
return syn::Error::new(variant.span(), "Variants cannot have any fields")
.to_compile_error()
.into();
}
let mut name_attr: Option<String> = None;
for attr in &variant.attrs {
if attr.path.is_ident("name") {
match attr.parse_meta() {
Ok(syn::Meta::NameValue(syn::MetaNameValue {
lit: syn::Lit::Str(s),
..
})) => {
if name_attr.is_none() {
name_attr = Some(s.value());
} else {
return syn::Error::new(attr.span(), "Duplicate name attribute")
.to_compile_error()
.into();
}
}
_ => {
return syn::Error::new(
attr.span(),
"The name attribute should be a key-value pair with a string argument: #[name = \"foo bar\"]",
)
.to_compile_error()
.into()
}
};
}
}
match name_attr {
Some(name) => variant_names.push(name),
None => variant_names.push(variant.ident.to_string()),
}
let variant_ident = &variant.ident;
to_index_tokens.push(quote! { #struct_name::#variant_ident => #variant_idx, });
from_index_tokens.push(quote! { #variant_idx => #struct_name::#variant_ident, });
}
let from_index_default_tokens = variants.first().map(|v| {
let variant_ident = &v.ident;
quote! { _ => #struct_name::#variant_ident, }
});
quote! {
impl Enum for #struct_name {
fn variants() -> &'static [&'static str] {
&[#(#variant_names),*]
}
fn to_index(self) -> usize {
match self {
#(#to_index_tokens)*
}
}
fn from_index(index: usize) -> Self {
match index {
#(#from_index_tokens)*
#from_index_default_tokens
}
}
}
}
.into()
}

363
nih_plug_derive/src/lib.rs
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@ -1,365 +1,16 @@
extern crate proc_macro;
use proc_macro::TokenStream;
use quote::quote;
use std::collections::HashSet;
use syn::spanned::Spanned;
/// Derive the `Params` trait for your plugin's parameters struct. See the `Plugin` trait.
#[proc_macro_derive(Params, attributes(id, persist, nested))]
pub fn derive_params(input: TokenStream) -> TokenStream {
let ast = syn::parse_macro_input!(input as syn::DeriveInput);
let struct_name = &ast.ident;
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
// parmaeters. 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.
let mut param_mapping_insert_tokens = Vec::new();
let mut param_id_string_tokens = Vec::new();
let mut field_serialize_tokens = Vec::new();
let mut field_deserialize_tokens = Vec::new();
let mut nested_fields_idents = Vec::new();
// We'll also enforce that there are no duplicate keys at compile time
// TODO: This doesn't work for nested fields since we don't know anything about the fields on
// the nested structs
let mut param_ids = HashSet::new();
let mut persist_ids = HashSet::new();
for field in fields.named {
let field_name = match &field.ident {
Some(ident) => ident,
_ => continue,
};
// These two attributes are mutually exclusive
let mut id_attr: Option<String> = None;
let mut persist_attr: Option<String> = None;
let mut nested = 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 id_attr.is_none() {
id_attr = Some(s.value());
} else {
return syn::Error::new(attr.span(), "Duplicate id attribute")
.to_compile_error()
.into();
}
}
_ => {
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 persist_attr.is_none() {
persist_attr = Some(s.value());
} else {
return syn::Error::new(attr.span(), "Duplicate persist attribute")
.to_compile_error()
.into();
}
}
_ => {
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") {
match attr.parse_meta() {
Ok(syn::Meta::Path(_)) => {
if !nested {
nested = true;
} else {
return syn::Error::new(attr.span(), "Duplicate nested attribute")
.to_compile_error()
.into();
}
}
_ => {
return syn::Error::new(
attr.span(),
"The nested attribute should not have any arguments: #[nested]",
)
.to_compile_error()
.into();
}
};
}
}
match (id_attr, persist_attr) {
(Some(param_id), None) => {
if !param_ids.insert(param_id.clone()) {
return syn::Error::new(
field.span(),
"Multiple fields with the same parameter ID found",
)
.to_compile_error()
.into();
}
// The specific parameter types know how to convert themselves into the correct ParamPtr
// variant
param_mapping_insert_tokens
.push(quote! { param_map.insert(#param_id, self.#field_name.as_ptr()); });
param_id_string_tokens.push(quote! { #param_id, });
}
(None, Some(stable_name)) => {
if !persist_ids.insert(stable_name.clone()) {
return syn::Error::new(
field.span(),
"Multiple persisted fields with the same ID found",
)
.to_compile_error()
.into();
}
// We don't know anything about the field types, but because we can generate this
// function we get type erasure for free since we only need to worry about byte
// vectors
field_serialize_tokens.push(quote! {
match ::nih_plug::param::internals::PersistentField::map(
&self.#field_name,
::nih_plug::param::internals::serialize_field,
) {
Ok(data) => {
serialized.insert(String::from(#stable_name), data);
}
Err(err) => {
::nih_plug::nih_log!("Could not serialize '{}': {}", #stable_name, err)
}
};
});
field_deserialize_tokens.push(quote! {
#stable_name => {
match ::nih_plug::param::internals::deserialize_field(&data) {
Ok(deserialized) => {
::nih_plug::param::internals::PersistentField::set(
&self.#field_name,
deserialized,
);
}
Err(err) => {
::nih_plug::nih_log!(
"Could not deserialize '{}': {}",
#stable_name,
err
)
}
};
}
});
}
(Some(_), Some(_)) => {
return syn::Error::new(
field.span(),
"The id and persist attributes are mutually exclusive",
)
.to_compile_error()
.into();
}
(None, None) => (),
}
if nested {
nested_fields_idents.push(field_name.clone());
}
}
quote! {
impl Params for #struct_name {
fn param_map(
self: std::pin::Pin<&Self>,
) -> std::collections::HashMap<&'static str, nih_plug::param::internals::ParamPtr> {
// This may not be in scope otherwise
use ::nih_plug::param::Param;
let mut param_map = std::collections::HashMap::new();
#(#param_mapping_insert_tokens)*
let nested_fields: &[&dyn Params] = &[#(&self.#nested_fields_idents),*];
for nested_params in nested_fields {
unsafe { param_map.extend(Pin::new_unchecked(*nested_params).param_map()) };
}
param_map
}
fn param_ids(self: std::pin::Pin<&Self>) -> Vec<&'static str> {
let mut ids = vec![#(#param_id_string_tokens)*];
let nested_fields: &[&dyn Params] = &[#(&self.#nested_fields_idents),*];
for nested_params in nested_fields {
unsafe { ids.append(&mut Pin::new_unchecked(*nested_params).param_ids()) };
}
ids
}
fn serialize_fields(&self) -> ::std::collections::HashMap<String, String> {
let mut serialized = ::std::collections::HashMap::new();
#(#field_serialize_tokens)*
let nested_fields: &[&dyn Params] = &[#(&self.#nested_fields_idents),*];
for nested_params in nested_fields {
unsafe { serialized.extend(Pin::new_unchecked(*nested_params).serialize_fields()) };
}
serialized
}
fn deserialize_fields(&self, serialized: &::std::collections::HashMap<String, String>) {
for (field_name, data) in serialized {
match field_name.as_str() {
#(#field_deserialize_tokens)*
_ => ::nih_plug::nih_log!("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.
let nested_fields: &[&dyn Params] = &[#(&self.#nested_fields_idents),*];
for nested_params in nested_fields {
unsafe { Pin::new_unchecked(*nested_params).deserialize_fields(serialized) };
}
}
}
}
.into()
}
mod enums;
mod params;
/// Derive the `Enum` trait for your simple enum parameters. See `EnumParam` for more information.
#[proc_macro_derive(Enum, attributes(name))]
pub fn derive_enum(input: TokenStream) -> TokenStream {
let ast = syn::parse_macro_input!(input as syn::DeriveInput);
let struct_name = &ast.ident;
let variants = match ast.data {
// syn::Data::Struct(syn::DataStruct {
// fields: syn::Fields::Named(named_fields),
// ..
// }) => named_fields,
syn::Data::Enum(syn::DataEnum { variants, .. }) => variants,
_ => {
return syn::Error::new(ast.span(), "Deriving Enum is only supported on enums")
.to_compile_error()
.into()
}
};
// The `Enum` trait is super simple: variant names are mapped to their index in the declaration
// order, and the names are either just the variant name or a `#[name = "..."]` attribute in
// case the name should contain a space.
let mut variant_names = Vec::new();
let mut to_index_tokens = Vec::new();
let mut from_index_tokens = Vec::new();
for (variant_idx, variant) in variants.iter().enumerate() {
if !variant.fields.is_empty() {
return syn::Error::new(variant.span(), "Variants cannot have any fields")
.to_compile_error()
.into();
enums::derive_enum(input)
}
let mut name_attr: Option<String> = None;
for attr in &variant.attrs {
if attr.path.is_ident("name") {
match attr.parse_meta() {
Ok(syn::Meta::NameValue(syn::MetaNameValue {
lit: syn::Lit::Str(s),
..
})) => {
if name_attr.is_none() {
name_attr = Some(s.value());
} else {
return syn::Error::new(attr.span(), "Duplicate name attribute")
.to_compile_error()
.into();
}
}
_ => {
return syn::Error::new(
attr.span(),
"The name attribute should be a key-value pair with a string argument: #[name = \"foo bar\"]",
)
.to_compile_error()
.into()
}
};
}
}
match name_attr {
Some(name) => variant_names.push(name),
None => variant_names.push(variant.ident.to_string()),
}
let variant_ident = &variant.ident;
to_index_tokens.push(quote! { #struct_name::#variant_ident => #variant_idx, });
from_index_tokens.push(quote! { #variant_idx => #struct_name::#variant_ident, });
}
let from_index_default_tokens = variants.first().map(|v| {
let variant_ident = &v.ident;
quote! { _ => #struct_name::#variant_ident, }
});
quote! {
impl Enum for #struct_name {
fn variants() -> &'static [&'static str] {
&[#(#variant_names),*]
}
fn to_index(self) -> usize {
match self {
#(#to_index_tokens)*
}
}
fn from_index(index: usize) -> Self {
match index {
#(#from_index_tokens)*
#from_index_default_tokens
}
}
}
}
.into()
/// Derive the `Params` trait for your plugin's parameters struct. See the `Plugin` trait.
#[proc_macro_derive(Params, attributes(id, persist, nested))]
pub fn derive_params(input: TokenStream) -> TokenStream {
params::derive_params(input)
}

263
nih_plug_derive/src/params.rs Normal file
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@ -0,0 +1,263 @@
use proc_macro::TokenStream;
use quote::quote;
use std::collections::HashSet;
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 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
// parmaeters. 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.
let mut param_mapping_insert_tokens = Vec::new();
let mut param_id_string_tokens = Vec::new();
let mut field_serialize_tokens = Vec::new();
let mut field_deserialize_tokens = Vec::new();
let mut nested_fields_idents = Vec::new();
// We'll also enforce that there are no duplicate keys at compile time
// TODO: This doesn't work for nested fields since we don't know anything about the fields on
// the nested structs
let mut param_ids = HashSet::new();
let mut persist_ids = HashSet::new();
for field in fields.named {
let field_name = match &field.ident {
Some(ident) => ident,
_ => continue,
};
// These two attributes are mutually exclusive
let mut id_attr: Option<String> = None;
let mut persist_attr: Option<String> = None;
let mut nested = 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 id_attr.is_none() {
id_attr = Some(s.value());
} else {
return syn::Error::new(attr.span(), "Duplicate id attribute")
.to_compile_error()
.into();
}
}
_ => {
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 persist_attr.is_none() {
persist_attr = Some(s.value());
} else {
return syn::Error::new(attr.span(), "Duplicate persist attribute")
.to_compile_error()
.into();
}
}
_ => {
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") {
match attr.parse_meta() {
Ok(syn::Meta::Path(_)) => {
if !nested {
nested = true;
} else {
return syn::Error::new(attr.span(), "Duplicate nested attribute")
.to_compile_error()
.into();
}
}
_ => {
return syn::Error::new(
attr.span(),
"The nested attribute should not have any arguments: #[nested]",
)
.to_compile_error()
.into();
}
};
}
}
match (id_attr, persist_attr) {
(Some(param_id), None) => {
if !param_ids.insert(param_id.clone()) {
return syn::Error::new(
field.span(),
"Multiple fields with the same parameter ID found",
)
.to_compile_error()
.into();
}
// The specific parameter types know how to convert themselves into the correct ParamPtr
// variant
param_mapping_insert_tokens
.push(quote! { param_map.insert(#param_id, self.#field_name.as_ptr()); });
param_id_string_tokens.push(quote! { #param_id, });
}
(None, Some(stable_name)) => {
if !persist_ids.insert(stable_name.clone()) {
return syn::Error::new(
field.span(),
"Multiple persisted fields with the same ID found",
)
.to_compile_error()
.into();
}
// We don't know anything about the field types, but because we can generate this
// function we get type erasure for free since we only need to worry about byte
// vectors
field_serialize_tokens.push(quote! {
match ::nih_plug::param::internals::PersistentField::map(
&self.#field_name,
::nih_plug::param::internals::serialize_field,
) {
Ok(data) => {
serialized.insert(String::from(#stable_name), data);
}
Err(err) => {
::nih_plug::nih_log!("Could not serialize '{}': {}", #stable_name, err)
}
};
});
field_deserialize_tokens.push(quote! {
#stable_name => {
match ::nih_plug::param::internals::deserialize_field(&data) {
Ok(deserialized) => {
::nih_plug::param::internals::PersistentField::set(
&self.#field_name,
deserialized,
);
}
Err(err) => {
::nih_plug::nih_log!(
"Could not deserialize '{}': {}",
#stable_name,
err
)
}
};
}
});
}
(Some(_), Some(_)) => {
return syn::Error::new(
field.span(),
"The id and persist attributes are mutually exclusive",
)
.to_compile_error()
.into();
}
(None, None) => (),
}
if nested {
nested_fields_idents.push(field_name.clone());
}
}
quote! {
impl Params for #struct_name {
fn param_map(
self: std::pin::Pin<&Self>,
) -> std::collections::HashMap<&'static str, nih_plug::param::internals::ParamPtr> {
// This may not be in scope otherwise
use ::nih_plug::param::Param;
let mut param_map = std::collections::HashMap::new();
#(#param_mapping_insert_tokens)*
let nested_fields: &[&dyn Params] = &[#(&self.#nested_fields_idents),*];
for nested_params in nested_fields {
unsafe { param_map.extend(Pin::new_unchecked(*nested_params).param_map()) };
}
param_map
}
fn param_ids(self: std::pin::Pin<&Self>) -> Vec<&'static str> {
let mut ids = vec![#(#param_id_string_tokens)*];
let nested_fields: &[&dyn Params] = &[#(&self.#nested_fields_idents),*];
for nested_params in nested_fields {
unsafe { ids.append(&mut Pin::new_unchecked(*nested_params).param_ids()) };
}
ids
}
fn serialize_fields(&self) -> ::std::collections::HashMap<String, String> {
let mut serialized = ::std::collections::HashMap::new();
#(#field_serialize_tokens)*
let nested_fields: &[&dyn Params] = &[#(&self.#nested_fields_idents),*];
for nested_params in nested_fields {
unsafe { serialized.extend(Pin::new_unchecked(*nested_params).serialize_fields()) };
}
serialized
}
fn deserialize_fields(&self, serialized: &::std::collections::HashMap<String, String>) {
for (field_name, data) in serialized {
match field_name.as_str() {
#(#field_deserialize_tokens)*
_ => ::nih_plug::nih_log!("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.
let nested_fields: &[&dyn Params] = &[#(&self.#nested_fields_idents),*];
for nested_params in nested_fields {
unsafe { Pin::new_unchecked(*nested_params).deserialize_fields(serialized) };
}
}
}
}
.into()
}

1
src/param/internals.rs
View file

@ -5,6 +5,7 @@ use std::pin::Pin;
use super::Param;
pub use nih_plug_derive::Params;
/// Re-export for use in the [`Params`] proc-macro.
pub use serde_json::from_str as deserialize_field;
/// Re-export for use in the [`Params`] proc-macro.

5
src/prelude.rs
View file

@ -1,7 +1,4 @@
// Re-export the proc macro
pub use nih_plug_derive::Params;
// And the other macros
// Re-export the macros, derive macros are already re-exported ferom their respectivem odules
pub use super::nih_debug_assert;
pub use super::nih_debug_assert_eq;
pub use super::nih_debug_assert_failure;