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Allow for remapping type parameters in type substitutions (#735)
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* feat!: Allow for remapping type parameters in type substitutions

* chore: cargo fmt

* chore: cargo clippy

* chore: Remove some old code

* a little tidy

* address comment nit

Co-authored-by: James Wilson <james@jsdw.me>
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@Xanewok @jsdw
Xanewok and jsdw authored Jan 19, 2023
1 parent b7a29a5 commit 977f2a3
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Showing 14 changed files with 541 additions and 331 deletions.
8 changes: 7 additions & 1 deletion cli/src/commands/codegen.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,10 @@ use std::{
io::Read,
path::PathBuf,
};
use subxt_codegen::DerivesRegistry;
use subxt_codegen::{
DerivesRegistry,
TypeSubstitutes,
};

/// Generate runtime API client code from metadata.
///
Expand Down Expand Up @@ -95,10 +98,13 @@ fn codegen(
derives.extend_for_type(ty, std::iter::once(derive), &crate_path)
}

let type_substitutes = TypeSubstitutes::new(&crate_path);

let runtime_api = subxt_codegen::generate_runtime_api_from_bytes(
item_mod,
metadata_bytes,
derives,
type_substitutes,
crate_path,
);
println!("{}", runtime_api);
Expand Down
78 changes: 24 additions & 54 deletions codegen/src/api/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ use crate::{
CompositeDef,
CompositeDefFields,
TypeGenerator,
TypeSubstitutes,
},
utils::{
fetch_metadata_bytes_blocking,
Expand All @@ -39,7 +40,6 @@ use quote::{
quote,
};
use std::{
collections::HashMap,
fs,
io::Read,
path,
Expand All @@ -54,13 +54,15 @@ use syn::parse_quote;
/// * `item_mod` - The module declaration for which the API is implemented.
/// * `path` - The path to the scale encoded metadata of the runtime node.
/// * `derives` - Provide custom derives for the generated types.
/// * `type_substitutes` - Provide custom type substitutes.
/// * `crate_path` - Path to the `subxt` crate.
///
/// **Note:** This is a wrapper over [RuntimeGenerator] for static metadata use-cases.
pub fn generate_runtime_api_from_path<P>(
item_mod: syn::ItemMod,
path: P,
derives: DerivesRegistry,
type_substitutes: TypeSubstitutes,
crate_path: CratePath,
) -> TokenStream2
where
Expand All @@ -74,7 +76,13 @@ where
file.read_to_end(&mut bytes)
.unwrap_or_else(|e| abort_call_site!("Failed to read metadata file: {}", e));

generate_runtime_api_from_bytes(item_mod, &bytes, derives, crate_path)
generate_runtime_api_from_bytes(
item_mod,
&bytes,
derives,
type_substitutes,
crate_path,
)
}

/// Generates the API for interacting with a substrate runtime, using metadata
Expand All @@ -86,42 +94,52 @@ where
/// * `item_mod` - The module declaration for which the API is implemented.
/// * `url` - HTTP/WS URL to the substrate node you'd like to pull metadata from.
/// * `derives` - Provide custom derives for the generated types.
/// * `type_substitutes` - Provide custom type substitutes.
/// * `crate_path` - Path to the `subxt` crate.
///
/// **Note:** This is a wrapper over [RuntimeGenerator] for static metadata use-cases.
pub fn generate_runtime_api_from_url(
item_mod: syn::ItemMod,
url: &Uri,
derives: DerivesRegistry,
type_substitutes: TypeSubstitutes,
crate_path: CratePath,
) -> TokenStream2 {
let bytes = fetch_metadata_bytes_blocking(url)
.unwrap_or_else(|e| abort_call_site!("Failed to obtain metadata: {}", e));

generate_runtime_api_from_bytes(item_mod, &bytes, derives, crate_path)
generate_runtime_api_from_bytes(
item_mod,
&bytes,
derives,
type_substitutes,
crate_path,
)
}

/// Generates the API for interacting with a substrate runtime, using metadata bytes.
///
/// # Arguments
///
/// * `item_mod` - The module declaration for which the API is implemented.
/// * `url` - HTTP/WS URL to the substrate node you'd like to pull metadata from.
/// * `bytes` - The raw metadata bytes.
/// * `derives` - Provide custom derives for the generated types.
/// * `type_substitutes` - Provide custom type substitutes.
/// * `crate_path` - Path to the `subxt` crate.
///
/// **Note:** This is a wrapper over [RuntimeGenerator] for static metadata use-cases.
pub fn generate_runtime_api_from_bytes(
item_mod: syn::ItemMod,
bytes: &[u8],
derives: DerivesRegistry,
type_substitutes: TypeSubstitutes,
crate_path: CratePath,
) -> TokenStream2 {
let metadata = frame_metadata::RuntimeMetadataPrefixed::decode(&mut &bytes[..])
.unwrap_or_else(|e| abort_call_site!("Failed to decode metadata: {}", e));

let generator = RuntimeGenerator::new(metadata);
generator.generate_runtime(item_mod, derives, crate_path)
generator.generate_runtime(item_mod, derives, type_substitutes, crate_path)
}

/// Create the API for interacting with a Substrate runtime.
Expand Down Expand Up @@ -152,61 +170,13 @@ impl RuntimeGenerator {
&self,
item_mod: syn::ItemMod,
derives: DerivesRegistry,
type_substitutes: TypeSubstitutes,
crate_path: CratePath,
) -> TokenStream2 {
let item_mod_attrs = item_mod.attrs.clone();
let item_mod_ir = ir::ItemMod::from(item_mod);
let default_derives = derives.default_derives();

// Some hardcoded default type substitutes, can be overridden by user
let mut type_substitutes = [
(
"bitvec::order::Lsb0",
parse_quote!(#crate_path::utils::bits::Lsb0),
),
(
"bitvec::order::Msb0",
parse_quote!(#crate_path::utils::bits::Msb0),
),
(
"sp_core::crypto::AccountId32",
parse_quote!(#crate_path::utils::AccountId32),
),
(
"sp_runtime::multiaddress::MultiAddress",
parse_quote!(#crate_path::utils::MultiAddress),
),
(
"primitive_types::H160",
parse_quote!(#crate_path::utils::H160),
),
(
"primitive_types::H256",
parse_quote!(#crate_path::utils::H256),
),
(
"primitive_types::H512",
parse_quote!(#crate_path::utils::H512),
),
(
"frame_support::traits::misc::WrapperKeepOpaque",
parse_quote!(#crate_path::utils::WrapperKeepOpaque),
),
// BTreeMap and BTreeSet impose an `Ord` constraint on their key types. This
// can cause an issue with generated code that doesn't impl `Ord` by default.
// Decoding them to Vec by default (KeyedVec is just an alias for Vec with
// suitable type params) avoids these issues.
("BTreeMap", parse_quote!(#crate_path::utils::KeyedVec)),
("BTreeSet", parse_quote!(::std::vec::Vec)),
]
.iter()
.map(|(path, substitute): &(&str, syn::TypePath)| {
(path.to_string(), substitute.clone())
})
.collect::<HashMap<_, _>>();

type_substitutes.extend(item_mod_ir.type_substitutes().into_iter());

let type_gen = TypeGenerator::new(
&self.metadata.types,
"runtime_types",
Expand Down
129 changes: 4 additions & 125 deletions codegen/src/ir.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3,19 +3,15 @@
// see LICENSE for license details.

use proc_macro_error::abort;
use std::collections::HashMap;
use syn::{
spanned::Spanned as _,
token,
};
use syn::token;

#[derive(Debug, PartialEq, Eq)]
pub struct ItemMod {
vis: syn::Visibility,
mod_token: token::Mod,
pub ident: syn::Ident,
brace: token::Brace,
items: Vec<Item>,
items: Vec<syn::Item>,
}

impl From<syn::ItemMod> for ItemMod {
Expand All @@ -32,130 +28,13 @@ impl From<syn::ItemMod> for ItemMod {
mod_token: module.mod_token,
ident: module.ident,
brace,
items: items.into_iter().map(From::from).collect(),
items,
}
}
}

impl ItemMod {
pub fn type_substitutes(&self) -> HashMap<String, syn::TypePath> {
self.items
.iter()
.filter_map(|item| {
if let Item::Subxt(SubxtItem::TypeSubstitute {
generated_type_path,
substitute_with: substitute_type,
}) = item
{
Some((generated_type_path.clone(), substitute_type.clone()))
} else {
None
}
})
.collect()
}

pub fn rust_items(&self) -> impl Iterator<Item = &syn::Item> {
self.items.iter().filter_map(Item::as_rust)
}
}

#[allow(clippy::large_enum_variant)]
#[derive(Debug, PartialEq, Eq)]
pub enum Item {
Rust(syn::Item),
Subxt(SubxtItem),
}

impl Item {
pub fn as_rust(&self) -> Option<&syn::Item> {
match self {
Item::Rust(item) => Some(item),
_ => None,
}
}
}

impl From<syn::Item> for Item {
fn from(item: syn::Item) -> Self {
if let syn::Item::Use(ref use_) = item {
let substitute_attrs = use_
.attrs
.iter()
.map(|attr| {
let meta = attr.parse_meta().unwrap_or_else(|e| {
abort!(attr.span(), "Error parsing attribute: {}", e)
});
<attrs::Subxt as darling::FromMeta>::from_meta(&meta).unwrap_or_else(
|e| abort!(attr.span(), "Error parsing attribute meta: {}", e),
)
})
.collect::<Vec<_>>();
if substitute_attrs.len() > 1 {
abort!(
use_.attrs[0].span(),
"Duplicate `substitute_type` attributes"
)
}
if let Some(attr) = substitute_attrs.get(0) {
let use_path = &use_.tree;
let substitute_with: syn::TypePath = syn::parse_quote!( #use_path );

let is_crate = substitute_with
.path
.segments
.first()
.map(|segment| segment.ident == "crate")
.unwrap_or(false);

// Check if the substitute path is a global absolute path, meaning it
// is prefixed with `::` or `crate`.
//
// Note: the leading colon is lost when parsing to `syn::TypePath` via
// `syn::parse_quote!`. Therefore, inspect `use_`'s leading colon.
if use_.leading_colon.is_none() && !is_crate {
abort!(
use_path.span(),
"The substitute path must be a global absolute path; try prefixing with `::` or `crate`"
)
}

let type_substitute = SubxtItem::TypeSubstitute {
generated_type_path: attr.substitute_type(),
substitute_with,
};
Self::Subxt(type_substitute)
} else {
Self::Rust(item)
}
} else {
Self::Rust(item)
}
}
}

#[derive(Debug, PartialEq, Eq)]
pub enum SubxtItem {
TypeSubstitute {
generated_type_path: String,
substitute_with: syn::TypePath,
},
}

mod attrs {
use darling::FromMeta;

#[derive(Debug, FromMeta)]
#[darling(rename_all = "snake_case")]
pub enum Subxt {
SubstituteType(String),
}

impl Subxt {
pub fn substitute_type(&self) -> String {
match self {
Self::SubstituteType(path) => path.clone(),
}
}
self.items.iter()
}
}
7 changes: 5 additions & 2 deletions codegen/src/lib.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,7 @@
//! use std::fs;
//! use codec::Decode;
//! use frame_metadata::RuntimeMetadataPrefixed;
//! use subxt_codegen::{CratePath, DerivesRegistry};
//! use subxt_codegen::{CratePath, DerivesRegistry, TypeSubstitutes};
//!
//! let encoded = fs::read("../artifacts/polkadot_metadata.scale").unwrap();
//!
Expand All @@ -33,9 +33,11 @@
//! );
//! // Default module derivatives.
//! let mut derives = DerivesRegistry::new(&CratePath::default());
//! // Default type substitutes.
//! let substs = TypeSubstitutes::new(&CratePath::default());
//! // Generate the Runtime API.
//! let generator = subxt_codegen::RuntimeGenerator::new(metadata);
//! let runtime_api = generator.generate_runtime(item_mod, derives, CratePath::default());
//! let runtime_api = generator.generate_runtime(item_mod, derives, substs, CratePath::default());
//! println!("{}", runtime_api);
//! ```

Expand All @@ -60,5 +62,6 @@ pub use self::{
DerivesRegistry,
Module,
TypeGenerator,
TypeSubstitutes,
},
};
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