feat(builtins): use proc macro for builtins

Cargo.lock

@@ -33,18 +33,65 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "darling"
+version = "0.14.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4529658bdda7fd6769b8614be250cdcfc3aeb0ee72fe66f9e41e5e5eb73eac02"
+dependencies = [
+ "darling_core",
+ "darling_macro",
+]
+
+[[package]]
+name = "darling_core"
+version = "0.14.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "649c91bc01e8b1eac09fb91e8dbc7d517684ca6be8ebc75bb9cafc894f9fdb6f"
+dependencies = [
+ "fnv",
+ "ident_case",
+ "proc-macro2",
+ "quote",
+ "strsim",
+ "syn",
+]
+
+[[package]]
+name = "darling_macro"
+version = "0.14.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddfc69c5bfcbd2fc09a0f38451d2daf0e372e367986a83906d1b0dbc88134fb5"
+dependencies = [
+ "darling_core",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "encode_unicode"
 version = "0.3.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a357d28ed41a50f9c765dbfe56cbc04a64e53e5fc58ba79fbc34c10ef3df831f"
 
+[[package]]
+name = "fnv"
+version = "1.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f9eec918d3f24069decb9af1554cad7c880e2da24a9afd88aca000531ab82c1"
+
 [[package]]
 name = "hashbrown"
 version = "0.12.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8a9ee70c43aaf417c914396645a0fa852624801b24ebb7ae78fe8272889ac888"
 
+[[package]]
+name = "ident_case"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9e0384b61958566e926dc50660321d12159025e767c18e043daf26b70104c39"
+
 [[package]]
 name = "indexmap"
 version = "1.9.1"
@@ -114,6 +161,18 @@ dependencies = [
  "oyster_runtime",
 ]
 
+[[package]]
+name = "oyster_builtin_proc"
+version = "0.0.0"
+dependencies = [
+ "darling",
+ "oyster_runtime",
+ "proc-macro-crate",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "oyster_lineedit"
 version = "0.0.0"
@@ -132,24 +191,36 @@ version = "0.0.0"
 dependencies = [
  "insta",
  "nix",
+ "oyster_builtin_proc",
  "oyster_parser",
  "thiserror",
 ]
 
 [[package]]
-name = "proc-macro2"
+name = "proc-macro-crate"
-version = "1.0.40"
+version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dd96a1e8ed2596c337f8eae5f24924ec83f5ad5ab21ea8e455d3566c69fbcaf7"
+checksum = "eda0fc3b0fb7c975631757e14d9049da17374063edb6ebbcbc54d880d4fe94e9"
+dependencies = [
+ "once_cell",
+ "thiserror",
+ "toml",
+]
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.47"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5ea3d908b0e36316caf9e9e2c4625cdde190a7e6f440d794667ed17a1855e725"
 dependencies = [
  "unicode-ident",
 ]
 
 [[package]]
 name = "quote"
-version = "1.0.20"
+version = "1.0.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3bcdf212e9776fbcb2d23ab029360416bb1706b1aea2d1a5ba002727cbcab804"
+checksum = "bbe448f377a7d6961e30f5955f9b8d106c3f5e449d493ee1b125c1d43c2b5179"
 dependencies = [
  "proc-macro2",
 ]
@@ -210,10 +281,16 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2e24979f63a11545f5f2c60141afe249d4f19f84581ea2138065e400941d83d3"
 
 [[package]]
-name = "syn"
+name = "strsim"
-version = "1.0.98"
+version = "0.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c50aef8a904de4c23c788f104b7dddc7d6f79c647c7c8ce4cc8f73eb0ca773dd"
+checksum = "73473c0e59e6d5812c5dfe2a064a6444949f089e20eec9a2e5506596494e4623"
+
+[[package]]
+name = "syn"
+version = "1.0.102"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3fcd952facd492f9be3ef0d0b7032a6e442ee9b361d4acc2b1d0c4aaa5f613a1"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -250,6 +327,15 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "toml"
+version = "0.5.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8d82e1a7758622a465f8cee077614c73484dac5b836c02ff6a40d5d1010324d7"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.1"

crates/oyster_builtin_proc/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "oyster_builtin_proc"
+version = "0.0.0"
+edition = "2021"
+
+[lib]
+doctest = false
+proc-macro = true
+
+[dependencies]
+darling = "~0.14.1"
+proc-macro-crate = "^1.2.1"
+proc-macro2 = { version = "1.0.47", default-features = false }
+quote = { version = "^1.0.21", default-features = false }
+syn = { version = "^1.0.102", default-features = false, features = [ "full" ] }
+
+[dev-dependencies]
+oyster_runtime = { path = "../oyster_runtime" }

crates/oyster_builtin_proc/src/lib.rs

@@ -0,0 +1,53 @@
+use darling::FromMeta;
+use proc_macro::TokenStream;
+use proc_macro2::Span;
+use proc_macro_crate::{crate_name, FoundCrate};
+use quote::quote;
+use syn::{parse_macro_input, AttributeArgs, Ident, ItemFn, Signature};
+
+#[derive(FromMeta)]
+struct AttrArgs {
+    #[darling(default)]
+    description: String,
+}
+
+#[proc_macro_attribute]
+pub fn builtin(attr: TokenStream, item: TokenStream) -> TokenStream {
+    let attrs = parse_macro_input!(attr as AttributeArgs);
+    let ItemFn {
+        vis, sig, block, ..
+    } = parse_macro_input!(item as ItemFn);
+    let Signature {
+        ident,
+        fn_token,
+        inputs,
+        ..
+    } = sig;
+
+    let name = ident.to_string();
+    let AttrArgs { description } = match AttrArgs::from_list(&attrs) {
+        Ok(args) => args,
+        Err(err) => return err.write_errors().into(),
+    };
+
+    let builtin = match crate_name("oyster_runtime").expect("oyster_runtime missing") {
+        FoundCrate::Itself => quote! { crate::builtins::Builtin },
+        FoundCrate::Name(name) => {
+            let ident = Ident::new(&name, Span::call_site());
+            quote! { #ident::builtins::Builtin }
+        }
+    };
+
+    TokenStream::from(quote! {
+        #[allow(non_upper_case_globals)]
+        #vis static #ident: #builtin = {
+            #fn_token #ident(#inputs) #block
+
+            #builtin {
+                name: #name,
+                description: #description,
+                fun: #ident,
+            }
+        };
+    })
+}

crates/oyster_builtin_proc/tests/it/main.rs

@@ -0,0 +1,10 @@
+use std::borrow::Cow;
+
+use oyster_builtin_proc::builtin;
+use oyster_runtime::Shell;
+
+#[test]
+fn normal_usage() {
+    #[builtin(description = "some text")]
+    fn test(_: &mut Shell, _: &[Cow<str>]) {}
+}

crates/oyster_runtime/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2021"
 doctest = false
 
 [dependencies]
+oyster_builtin_proc = { path = "../oyster_builtin_proc" }
 oyster_parser = { path = "../oyster_parser" }
 thiserror = "1.0.35"
 

crates/oyster_runtime/src/builtins/mod.rs

@@ -1,5 +1,7 @@
 use std::{borrow::Cow, collections::HashMap};
 
+use oyster_builtin_proc::builtin;
+
 use crate::Shell;
 
 #[derive(Clone, Copy)]
@@ -9,8 +11,8 @@ pub struct Builtin {
     pub fun: fn(shell: &mut Shell, args: &[Cow<str>]),
 }
 
-pub static HELP: Builtin = {
+#[builtin(description = "prints help for different builtins")]
-    pub fn help(shell: &mut Shell, _args: &[Cow<str>]) {
+fn help(shell: &mut Shell, _args: &[Cow<str>]) {
     println!(
         r"oyster help:
 
@@ -20,14 +22,7 @@ These are the loaded builtins:"
     for builtin in shell.builtins().iter() {
         println!("  {: <8} {}", builtin.name, builtin.description);
     }
-    }
+}
-
-    Builtin {
-        name: "help",
-        description: "prints help for different builtins",
-        fun: help,
-    }
-};
 
 /// Used to register and retrieve builtins.
 #[derive(Default)]
@@ -51,7 +46,7 @@ impl BuiltinMap {
 
     /// Add default builtins.
     pub fn add_defaults(&mut self) {
-        self.add(HELP);
+        self.add(help);
     }
 }
 

crates/oyster_runtime/tests/it/pipeline.rs

@@ -1,4 +1,5 @@
 use std::{
+    borrow::Cow,
     env,
     fs::File,
     io::{BufRead, BufReader, Write},
@@ -13,12 +14,19 @@ use nix::{
     sys,
     unistd::{self, ForkResult},
 };
-use oyster_runtime::{builtins::Builtin, Shell};
+use oyster_builtin_proc::builtin;
+use oyster_runtime::Shell;
 
 // TODO: test signal return codes
 
 ioctl_write_int_bad!(tiocsctty, libc::TIOCSCTTY);
 
+#[builtin(description = "test builtin")]
+fn test_builtin(_: &mut Shell, _: &[Cow<str>]) {
+    // XXX: this is a workaround around libtest's use of io::set_output_capture
+    let _ = write!(std::io::stdout(), "this is a test\n");
+}
+
 /// Forks to redirect stdin, stderr, stdout, then run the commands.
 /// Relies on inserting a NUL byte in the end, so there shouldn't be NUL in the output.
 fn collect_output<F>(mut f: F) -> String
@@ -184,14 +192,7 @@ fn simple_builtin() {
 
     let actual = collect_output(|| {
         let mut shell = Shell::new().unwrap();
-        shell.builtins_mut().add(Builtin {
+        shell.builtins_mut().add(test_builtin);
-            name: "test_builtin",
-            description: "test",
-            fun: |_, _| {
-                // XXX: this is a workaround around libtest's use of io::set_output_capture
-                let _ = write!(std::io::stdout(), "this is a test\n");
-            },
-        });
         shell.run(&ast).unwrap();
     });
 
@@ -220,14 +221,7 @@ fn builtin_redirection() {
 
     let actual = collect_output(|| {
         let mut shell = Shell::new().unwrap();
-        shell.builtins_mut().add(Builtin {
+        shell.builtins_mut().add(test_builtin);
-            name: "test_builtin",
-            description: "test",
-            fun: |_, _| {
-                // XXX: this is a workaround around libtest's use of io::set_output_capture
-                let _ = write!(std::io::stdout(), "this is a test\n");
-            },
-        });
         shell.run(&ast).unwrap();
     });