perf(core): improve binary size with api enum serde refactor (#3952)

Author: lucasfernog

.changes/binary-size-perf.md

@@ -0,0 +1,5 @@
+---
+"tauri": patch
+---
+
+Reduce the amount of generated code for the API endpoints.

Cargo.toml

@@ -24,6 +24,7 @@ exclude = [
 
 # default to small, optimized workspace release binaries
 [profile.release]
+strip = true
 panic = "abort"
 codegen-units = 1
 lto = true

core/tauri-macros/src/command_module.rs

@@ -2,35 +2,115 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-License-Identifier: MIT
 
-use heck::ToSnakeCase;
+use heck::{ToLowerCamelCase, ToSnakeCase};
 use proc_macro::TokenStream;
-use proc_macro2::{Span, TokenStream as TokenStream2, TokenTree};
+use proc_macro2::{Span, TokenStream as TokenStream2};
 
 use quote::{format_ident, quote, quote_spanned};
 use syn::{
   parse::{Parse, ParseStream},
+  parse_quote,
   spanned::Spanned,
-  Data, DeriveInput, Error, Fields, FnArg, Ident, ItemFn, LitStr, Pat, Token,
+  Data, DeriveInput, Error, Fields, Ident, ItemFn, LitStr, Token,
 };
 
-pub fn generate_run_fn(input: DeriveInput) -> TokenStream {
+pub(crate) fn generate_command_enum(mut input: DeriveInput) -> TokenStream {
+  let mut deserialize_functions = TokenStream2::new();
+  let mut errors = TokenStream2::new();
+
+  input.attrs.push(parse_quote!(#[allow(dead_code)]));
+
+  match &mut input.data {
+    Data::Enum(data_enum) => {
+      for variant in &mut data_enum.variants {
+        let mut feature: Option<Ident> = None;
+        let mut error_message: Option<String> = None;
+
+        for attr in &variant.attrs {
+          if attr.path.is_ident("cmd") {
+            let r = attr
+              .parse_args_with(|input: ParseStream| {
+                if let Ok(f) = input.parse::<Ident>() {
+                  feature.replace(f);
+                  input.parse::<Token![,]>()?;
+                  let error_message_raw: LitStr = input.parse()?;
+                  error_message.replace(error_message_raw.value());
+                }
+                Ok(quote!())
+              })
+              .unwrap_or_else(syn::Error::into_compile_error);
+            errors.extend(r);
+          }
+        }
+
+        if let Some(f) = feature {
+          let error_message = if let Some(e) = error_message {
+            let e = e.to_string();
+            quote!(#e)
+          } else {
+            quote!("This API is not enabled in the allowlist.")
+          };
+
+          let deserialize_function_name = quote::format_ident!("__{}_deserializer", variant.ident);
+          deserialize_functions.extend(quote! {
+            #[cfg(not(#f))]
+            #[allow(non_snake_case)]
+            fn #deserialize_function_name<'de, D, T>(deserializer: D) -> ::std::result::Result<T, D::Error>
+            where
+              D: ::serde::de::Deserializer<'de>,
+            {
+              ::std::result::Result::Err(::serde::de::Error::custom(crate::Error::ApiNotAllowlisted(#error_message.into()).to_string()))
+            }
+          });
+
+          let deserialize_function_name = deserialize_function_name.to_string();
+
+          variant
+          .attrs
+          .push(parse_quote!(#[cfg_attr(not(#f), serde(deserialize_with = #deserialize_function_name))]));
+        }
+      }
+    }
+    _ => {
+      return Error::new(
+        Span::call_site(),
+        "`command_enum` is only implemented for enums",
+      )
+      .to_compile_error()
+      .into()
+    }
+  };
+
+  TokenStream::from(quote! {
+    #errors
+    #input
+    #deserialize_functions
+  })
+}
+
+pub(crate) fn generate_run_fn(input: DeriveInput) -> TokenStream {
   let name = &input.ident;
   let data = &input.data;
 
+  let mut errors = TokenStream2::new();
+
   let mut is_async = false;
+
   let attrs = input.attrs;
   for attr in attrs {
     if attr.path.is_ident("cmd") {
-      let _ = attr.parse_args_with(|input: ParseStream| {
-        while let Some(token) = input.parse()? {
-          if let TokenTree::Ident(ident) = token {
-            is_async |= ident == "async";
+      let r = attr
+        .parse_args_with(|input: ParseStream| {
+          if let Ok(token) = input.parse::<Ident>() {
+            is_async = token == "async";
           }
-        }
-        Ok(())
-      });
+          Ok(quote!())
+        })
+        .unwrap_or_else(syn::Error::into_compile_error);
+      errors.extend(r);
     }
   }
+
   let maybe_await = if is_async { quote!(.await) } else { quote!() };
   let maybe_async = if is_async { quote!(async) } else { quote!() };
 
@@ -43,6 +123,30 @@ pub fn generate_run_fn(input: DeriveInput) -> TokenStream {
       for variant in &data_enum.variants {
         let variant_name = &variant.ident;
 
+        let mut feature = None;
+
+        for attr in &variant.attrs {
+          if attr.path.is_ident("cmd") {
+            let r = attr
+              .parse_args_with(|input: ParseStream| {
+                if let Ok(f) = input.parse::<Ident>() {
+                  feature.replace(f);
+                  input.parse::<Token![,]>()?;
+                  let _: LitStr = input.parse()?;
+                }
+                Ok(quote!())
+              })
+              .unwrap_or_else(syn::Error::into_compile_error);
+            errors.extend(r);
+          }
+        }
+
+        let maybe_feature_check = if let Some(f) = feature {
+          quote!(#[cfg(#f)])
+        } else {
+          quote!()
+        };
+
         let (fields_in_variant, variables) = match &variant.fields {
           Fields::Unit => (quote_spanned! { variant.span() => }, quote!()),
           Fields::Unnamed(fields) => {
@@ -73,9 +177,13 @@ pub fn generate_run_fn(input: DeriveInput) -> TokenStream {
         variant_execute_function_name.set_span(variant_name.span());
 
         matcher.extend(quote_spanned! {
-          variant.span() => #name::#variant_name #fields_in_variant => #name::#variant_execute_function_name(context, #variables)#maybe_await.map(Into::into),
+          variant.span() => #maybe_feature_check #name::#variant_name #fields_in_variant => #name::#variant_execute_function_name(context, #variables)#maybe_await.map(Into::into),
         });
       }
+
+      matcher.extend(quote! {
+        _ => Err(crate::error::into_anyhow("API not in the allowlist (https://tauri.studio/docs/api/config#tauri.allowlist)")),
+      });
     }
     _ => {
       return Error::new(
@@ -90,7 +198,8 @@ pub fn generate_run_fn(input: DeriveInput) -> TokenStream {
   let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
 
   let expanded = quote! {
-      impl #impl_generics #name #ty_generics #where_clause {
+    #errors
+    impl #impl_generics #name #ty_generics #where_clause {
         pub #maybe_async fn run<R: crate::Runtime>(self, context: crate::endpoints::InvokeContext<R>) -> super::Result<crate::endpoints::InvokeResponse> {
           match self {
             #matcher
@@ -105,26 +214,25 @@ pub fn generate_run_fn(input: DeriveInput) -> TokenStream {
 /// Attributes for the module enum variant handler.
 pub struct HandlerAttributes {
   allowlist: Ident,
-  error_message: String,
 }
 
 impl Parse for HandlerAttributes {
   fn parse(input: ParseStream) -> syn::Result<Self> {
-    let allowlist = input.parse()?;
-    input.parse::<Token![,]>()?;
-    let raw: LitStr = input.parse()?;
-    let error_message = raw.value();
     Ok(Self {
-      allowlist,
-      error_message,
+      allowlist: input.parse()?,
     })
   }
 }
 
+pub enum AllowlistCheckKind {
+  Runtime,
+  Serde,
+}
+
 pub struct HandlerTestAttributes {
   allowlist: Ident,
   error_message: String,
-  is_async: bool,
+  allowlist_check_kind: AllowlistCheckKind,
 }
 
 impl Parse for HandlerTestAttributes {
@@ -133,67 +241,56 @@ impl Parse for HandlerTestAttributes {
     input.parse::<Token![,]>()?;
     let error_message_raw: LitStr = input.parse()?;
     let error_message = error_message_raw.value();
-    let _ = input.parse::<Token![,]>();
-    let is_async = input
-      .parse::<Ident>()
-      .map(|i| i == "async")
-      .unwrap_or_default();
+    let allowlist_check_kind =
+      if let (Ok(_), Ok(i)) = (input.parse::<Token![,]>(), input.parse::<Ident>()) {
+        if i == "runtime" {
+          AllowlistCheckKind::Runtime
+        } else {
+          AllowlistCheckKind::Serde
+        }
+      } else {
+        AllowlistCheckKind::Serde
+      };
 
     Ok(Self {
       allowlist,
       error_message,
-      is_async,
+      allowlist_check_kind,
     })
   }
 }
 
 pub fn command_handler(attributes: HandlerAttributes, function: ItemFn) -> TokenStream2 {
   let allowlist = attributes.allowlist;
-  let error_message = attributes.error_message.as_str();
-  let signature = function.sig.clone();
 
   quote!(
     #[cfg(#allowlist)]
     #function
-
-    #[cfg(not(#allowlist))]
-    #[allow(unused_variables)]
-    #[allow(unused_mut)]
-    #signature {
-      Err(anyhow::anyhow!(crate::Error::ApiNotAllowlisted(#error_message.to_string()).to_string()))
-    }
   )
 }
 
 pub fn command_test(attributes: HandlerTestAttributes, function: ItemFn) -> TokenStream2 {
   let allowlist = attributes.allowlist;
-  let is_async = attributes.is_async;
   let error_message = attributes.error_message.as_str();
   let signature = function.sig.clone();
-  let test_name = function.sig.ident.clone();
-  let mut args = quote!();
-  for arg in &function.sig.inputs {
-    if let FnArg::Typed(t) = arg {
-      if let Pat::Ident(i) = &*t.pat {
-        let ident = &i.ident;
-        args.extend(quote!(#ident,))
-      }
-    }
-  }
 
-  let response = if is_async {
-    quote!(crate::async_runtime::block_on(
-      super::Cmd::#test_name(crate::test::mock_invoke_context(), #args)
-    ))
-  } else {
-    quote!(super::Cmd::#test_name(crate::test::mock_invoke_context(), #args))
+  let enum_variant_name = function.sig.ident.to_string().to_lower_camel_case();
+  let response = match attributes.allowlist_check_kind {
+    AllowlistCheckKind::Runtime => {
+      let test_name = function.sig.ident.clone();
+      quote!(super::Cmd::#test_name(crate::test::mock_invoke_context()))
+    }
+    AllowlistCheckKind::Serde => quote! {
+      serde_json::from_str::<super::Cmd>(&format!(r#"{{ "cmd": "{}", "data": null }}"#, #enum_variant_name))
+    },
   };
 
   quote!(
     #[cfg(#allowlist)]
     #function
 
     #[cfg(not(#allowlist))]
+    #[allow(unused_variables)]
     #[quickcheck_macros::quickcheck]
     #signature {
       if let Err(e) = #response {

core/tauri-macros/src/lib.rs

@@ -76,17 +76,25 @@ pub fn default_runtime(attributes: TokenStream, input: TokenStream) -> TokenStre
   runtime::default_runtime(attributes, input).into()
 }
 
+/// Prepares the command module enum.
+#[doc(hidden)]
+#[proc_macro_derive(CommandModule, attributes(cmd))]
+pub fn derive_command_module(input: TokenStream) -> TokenStream {
+  let input = parse_macro_input!(input as DeriveInput);
+  command_module::generate_run_fn(input)
+}
+
 /// Adds a `run` method to an enum (one of the tauri endpoint modules).
 /// The `run` method takes a `tauri::endpoints::InvokeContext`
 /// and returns a `tauri::Result<tauri::endpoints::InvokeResponse>`.
 /// It matches on each enum variant and call a method with name equal to the variant name, lowercased and snake_cased,
 /// passing the the context and the variant's fields as arguments.
 /// That function must also return the same `Result<InvokeResponse>`.
 #[doc(hidden)]
-#[proc_macro_derive(CommandModule, attributes(cmd))]
-pub fn derive_command_module(input: TokenStream) -> TokenStream {
+#[proc_macro_attribute]
+pub fn command_enum(_: TokenStream, input: TokenStream) -> TokenStream {
   let input = parse_macro_input!(input as DeriveInput);
-  command_module::generate_run_fn(input)
+  command_module::generate_command_enum(input)
 }
 
 #[doc(hidden)]

core/tauri/build.rs

@@ -60,6 +60,8 @@ fn main() {
     shell_execute: { any(shell_all, feature = "shell-execute") },
     shell_sidecar: { any(shell_all, feature = "shell-sidecar") },
     shell_open: { any(shell_all, feature = "shell-open") },
+    // helper for the command module macro
+    shell_script: { any(shell_execute, shell_sidecar) },
     // helper for the shell scope functionality
     shell_scope: { any(shell_execute, shell_sidecar, feature = "shell-open-api") },
 

core/tauri/scripts/bundle.js

@@ -17,7 +17,6 @@ mod cli;
 mod clipboard;
 mod dialog;
 mod event;
-#[allow(unused_imports)]
 mod file_system;
 mod global_shortcut;
 mod http;

core/tauri/src/endpoints.rs

@@ -5,9 +5,10 @@
 use super::InvokeContext;
 use crate::Runtime;
 use serde::Deserialize;
-use tauri_macros::CommandModule;
+use tauri_macros::{command_enum, CommandModule};
 
 /// The API descriptor.
+#[command_enum]
 #[derive(Deserialize, CommandModule)]
 #[serde(tag = "cmd", rename_all = "camelCase")]
 #[allow(clippy::enum_variant_names)]