mirror of
https://github.com/pezkuwichain/pezkuwi-subxt.git
synced 2026-04-22 07:58:02 +00:00
James Wilson
89 lines
3.0 KiB
Rust
89 lines
3.0 KiB
Rust
// Copyright 2019-2022 Parity Technologies (UK) Ltd.
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// This file is dual-licensed as Apache-2.0 or GPL-3.0.
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// see LICENSE for license details.
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use crate::{types::TypeGenerator, CratePath};
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use frame_metadata::{v14::RuntimeMetadataV14, PalletMetadata};
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use heck::ToSnakeCase as _;
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use proc_macro2::TokenStream as TokenStream2;
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use quote::{format_ident, quote};
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use scale_info::form::PortableForm;
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use super::CodegenError;
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/// Generate constants from the provided pallet's metadata.
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///
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/// The function creates a new module named `constants` under the pallet's module.
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/// ```ignore
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/// pub mod PalletName {
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/// pub mod constants {
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/// ...
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/// }
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/// }
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/// ```
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///
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/// The constants are exposed via the `ConstantsApi` wrapper.
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///
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/// Although the constants are defined in the provided static metadata, the API
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/// ensures that the constants are returned from the runtime metadata of the node.
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/// This ensures that if the node's constants change value, we'll always see the latest values.
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///
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/// # Arguments
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///
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/// - `metadata` - Runtime metadata from which the calls are generated.
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/// - `type_gen` - The type generator containing all types defined by metadata
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/// - `pallet` - Pallet metadata from which the calls are generated.
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/// - `types_mod_ident` - The ident of the base module that we can use to access the generated types from.
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pub fn generate_constants(
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metadata: &RuntimeMetadataV14,
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type_gen: &TypeGenerator,
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pallet: &PalletMetadata<PortableForm>,
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types_mod_ident: &syn::Ident,
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crate_path: &CratePath,
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should_gen_docs: bool,
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) -> Result<TokenStream2, CodegenError> {
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// Early return if the pallet has no constants.
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if pallet.constants.is_empty() {
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return Ok(quote!());
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}
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let constants = &pallet.constants;
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let constant_fns = constants.iter().map(|constant| {
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let fn_name = format_ident!("{}", constant.name.to_snake_case());
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let pallet_name = &pallet.name;
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let constant_name = &constant.name;
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let Ok(constant_hash) = subxt_metadata::get_constant_hash(metadata, pallet_name, constant_name) else {
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return Err(CodegenError::MissingConstantMetadata(constant_name.into(), pallet_name.into()));
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};
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let return_ty = type_gen.resolve_type_path(constant.ty.id());
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let docs = &constant.docs;
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let docs = should_gen_docs
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.then_some(quote! { #( #[doc = #docs ] )* })
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.unwrap_or_default();
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Ok(quote! {
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#docs
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pub fn #fn_name(&self) -> #crate_path::constants::Address<#return_ty> {
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#crate_path::constants::Address::new_static(
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#pallet_name,
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#constant_name,
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[#(#constant_hash,)*]
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)
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}
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})
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}).collect::<Result<Vec<_>, _>>()?;
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Ok(quote! {
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pub mod constants {
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use super::#types_mod_ident;
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pub struct ConstantsApi;
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impl ConstantsApi {
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#(#constant_fns)*
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}
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}
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})
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}
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