derive: add benchmark

This PR adds the crate "rinja_derive_standalone", which is just like
"rinja_derive", though not a "proc_macro". This way we can easily expose
it's internals for testing and benchmarking.

Right now, the PR is more or less a prove of concept, and it probably
needs a handful more useful benchmark use cases to be worth the hassle.

.github/workflows/rust.yml

@@ -32,7 +32,7 @@ jobs:
     strategy:
       matrix:
         package: [
-          rinja, rinja_actix, rinja_axum, rinja_derive, rinja_escape,
+          rinja, rinja_actix, rinja_axum, rinja_derive, rinja_derive_standalone, rinja_escape,
           rinja_parser, rinja_rocket, rinja_warp, testing,
         ]
     runs-on: ubuntu-latest

Cargo.toml

@@ -4,6 +4,7 @@ members = [
     "rinja_actix",
     "rinja_axum",
     "rinja_derive",
+    "rinja_derive_standalone",
     "rinja_escape",
     "rinja_parser",
     "rinja_rocket",

rinja_derive/src/heritage.rs

@@ -2,11 +2,12 @@ use std::collections::HashMap;
 use std::path::Path;
 use std::rc::Rc;
 
-use crate::config::Config;
-use crate::{CompileError, FileInfo};
 use parser::node::{BlockDef, Macro};
 use parser::{Node, Parsed, WithSpan};
 
+use crate::config::Config;
+use crate::{CompileError, FileInfo};
+
 pub(crate) struct Heritage<'a> {
     pub(crate) root: &'a Context<'a>,
     pub(crate) blocks: BlockAncestry<'a>,

rinja_derive/src/input.rs

@@ -4,12 +4,12 @@ use std::rc::Rc;
 use std::str::FromStr;
 
 use mime::Mime;
+use parser::{Node, Parsed, Syntax};
 use quote::ToTokens;
 use syn::punctuated::Punctuated;
 
 use crate::config::{get_template_source, Config};
 use crate::CompileError;
-use parser::{Node, Parsed, Syntax};
 
 pub(crate) struct TemplateInput<'a> {
     pub(crate) ast: &'a syn::DeriveInput,

rinja_derive/src/lib.rs

@@ -1,38 +1,57 @@
 #![deny(elided_lifetimes_in_paths)]
 #![deny(unreachable_pub)]
 
+mod config;
+mod generator;
+mod heritage;
+mod input;
+#[cfg(test)]
+mod tests;
+
 use std::collections::HashMap;
 use std::fmt;
 use std::path::Path;
 
-use proc_macro::TokenStream;
-use proc_macro2::Span;
-
-use parser::{generate_error_info, strip_common, ErrorInfo, ParseError};
-
-mod config;
 use config::{read_config_file, Config};
-mod generator;
 use generator::{Generator, MapChain};
-mod heritage;
 use heritage::{Context, Heritage};
-mod input;
 use input::{Print, TemplateArgs, TemplateInput};
-#[cfg(test)]
-mod tests;
+use parser::{generate_error_info, strip_common, ErrorInfo, ParseError};
+use proc_macro2::{Span, TokenStream};
 
+#[cfg(not(feature = "__standalone"))]
+macro_rules! pub_if_standalone {
+    (pub $($tt:tt)*) => {
+        $($tt)*
+    }
+}
+
+#[cfg(feature = "__standalone")]
+macro_rules! pub_if_standalone {
+    ($($tt:tt)*) => {
+        $($tt)*
+    }
+}
+
+#[cfg(not(feature = "__standalone"))]
 #[proc_macro_derive(Template, attributes(template))]
-pub fn derive_template(input: TokenStream) -> TokenStream {
-    let ast = syn::parse::<syn::DeriveInput>(input).unwrap();
-    match build_template(&ast) {
-        Ok(source) => source.parse().unwrap(),
-        Err(e) => {
-            let mut e = e.into_compile_error();
-            if let Ok(source) = build_skeleton(&ast) {
-                let source: TokenStream = source.parse().unwrap();
-                e.extend(source);
+pub fn derive_template(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    derive_template2(input.into()).into()
+}
+
+pub_if_standalone! {
+    pub fn derive_template2(input: TokenStream) -> TokenStream {
+        let ast = syn::parse2(input).unwrap();
+        match build_template(&ast) {
+            Ok(source) => source.parse().unwrap(),
+            Err(e) => {
+                let mut e = e.into_compile_error();
+                if let Ok(source) = build_skeleton(&ast) {
+                    let source: TokenStream = source.parse().unwrap();
+                    e.extend(source);
+                }
+                e
             }
-            e
         }
     }
 }
@@ -138,9 +157,7 @@ impl CompileError {
     }
 
     fn into_compile_error(self) -> TokenStream {
-        syn::Error::new(self.span, self.msg)
-            .to_compile_error()
-            .into()
+        syn::Error::new(self.span, self.msg).to_compile_error()
     }
 }
 

rinja_derive/src/tests.rs

@@ -1,7 +1,8 @@
-// Files containing tests for generated code.
+//! Files containing tests for generated code.
+
+use std::fmt::Write;
 
 use crate::build_template;
-use std::fmt::Write;
 
 #[test]
 fn check_if_let() {

rinja_derive_standalone/Cargo.toml

@@ -0,0 +1,42 @@
+[package]
+name = "rinja_derive_standalone"
+version = "0.13.0"
+description = "Procedural macro package for Rinja"
+homepage = "https://github.com/rinja-rs/rinja"
+repository = "https://github.com/rinja-rs/rinja"
+license = "MIT/Apache-2.0"
+workspace = ".."
+readme = "README.md"
+edition = "2021"
+rust-version = "1.65"
+
+[features]
+default = ["__standalone"]
+__standalone = []
+config = ["dep:serde", "dep:basic-toml"]
+humansize = []
+urlencode = []
+serde_json = []
+num-traits = []
+with-actix-web = []
+with-axum = []
+with-rocket = []
+with-warp = []
+
+[dependencies]
+parser = { package = "rinja_parser", version = "0.3", path = "../rinja_parser" }
+mime = "0.3"
+mime_guess = "2"
+proc-macro2 = "1"
+quote = "1"
+serde = { version = "1.0", optional = true, features = ["derive"] }
+syn = "2"
+basic-toml = { version = "0.1.1", optional = true }
+
+[dev-dependencies]
+criterion = "0.5"
+
+[[bench]]
+name = "derive-template"
+harness = false
+required-features = ["__standalone"]

rinja_derive_standalone/LICENSE-APACHE

@@ -0,0 +1 @@
+../LICENSE-APACHE

rinja_derive_standalone/LICENSE-MIT

@@ -0,0 +1 @@
+../LICENSE-MIT

rinja_derive_standalone/README.md

@@ -0,0 +1,5 @@
+This crate embeds the source of `rinja_derive`, but is not a `proc_macro`.
+This way we can more easily access the internals of the crate.
+
+To run the benchmark, execute `cargo bench` in this folder, or
+`cargo bench -p rinja_derive_standalone` in the project root.

rinja_derive_standalone/benches/derive-template.rs

@@ -0,0 +1,25 @@
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
+use quote::quote;
+
+criterion_main!(benches);
+criterion_group!(benches, functions);
+
+fn functions(c: &mut Criterion) {
+    c.bench_function("hello_world", hello_world);
+}
+
+fn hello_world(b: &mut criterion::Bencher<'_>) {
+    let ts = quote! {
+        #[derive(Template)]
+        #[template(
+            source = "<html><body><h1>Hello, {{user}}!</h1></body></html>",
+            ext = "html"
+        )]
+        struct Hello<'a> {
+            user: &'a str,
+        }
+    };
+    b.iter(|| {
+        rinja_derive_standalone::derive_template2(black_box(&ts).clone());
+    })
+}

rinja_derive_standalone/src

@@ -0,0 +1 @@
+../rinja_derive/src/

rinja_derive_standalone/templates

@@ -0,0 +1 @@
+../rinja_derive/templates/