Print nicer error messages

crates/lb/src/fs.rs

@@ -1,15 +1,15 @@
-//! The `lb:fs` module provides utilities for interacting with the file system asynchronously.
+//! The `lb:fs` library provides utilities for interacting with the file system asynchronously.
 //!
 //! # Exports
 //!
-//! See [`lb_libfs`] for items exported by this module.
+//! See [`lb_libfs`] for items exported by this library.
 use luaffi::{cdef, metatype};
 use std::io;
 use tokio::fs;
 
-/// Items exported by the `lb:fs` module.
+/// Items exported by the `lb:fs` library.
 ///
-/// This module can be obtained by calling `require` in Lua.
+/// This library can be obtained by calling `require` in Lua.
 ///
 /// ```lua
 /// local fs = require("lb:fs");

crates/lb/src/net.rs

@@ -1,9 +1,9 @@
-//! The `lb:net` module provides an asynchronous network API for creating TCP or UDP servers and
+//! The `lb:net` library provides an asynchronous network API for creating TCP or UDP servers and
 //! clients.
 //!
 //! # Exports
 //!
-//! See [`lb_libnet`] for items exported by this module.
+//! See [`lb_libnet`] for items exported by this library.
 use derive_more::{From, FromStr};
 use luaffi::{cdef, metatype};
 use std::{
@@ -12,9 +12,9 @@ use std::{
 };
 use tokio::net::{TcpListener, TcpSocket, TcpStream};
 
-/// Items exported by the `lb:net` module.
+/// Items exported by the `lb:net` library.
 ///
-/// This module can be obtained by calling `require` in Lua.
+/// This library can be obtained by calling `require` in Lua.
 ///
 /// ```lua
 /// local net = require("lb:net");

crates/lb/src/runtime.rs

@@ -41,6 +41,7 @@ impl Builder {
                 let mut s = State::new()?;
                 let mut chunk = Chunk::new(self.registry.done());
                 chunk.extend(include_bytes!("./runtime.lua"));
+                // println!("{chunk}");
                 s.eval(chunk.path("[luby]"), 0, 0)?;
                 s
             },

crates/luaffi/Cargo.toml

@@ -7,6 +7,10 @@ authors.workspace = true
 homepage.workspace = true
 repository.workspace = true
 
+[features]
+option_ref_abi = []
+option_string_abi = []
+
 [dependencies]
 bstr = "1.12.0"
 luaffi_impl = { path = "../luaffi_impl" }

crates/luaffi/src/lib.rs

@@ -11,13 +11,13 @@ use std::{
     mem,
 };
 
-pub mod future;
-pub mod string;
-
 #[doc(hidden)]
 #[path = "./internal.rs"]
 pub mod __internal;
+pub mod future;
+pub mod option;
 pub mod result;
+pub mod string;
 
 // Dummy function to ensure that strings passed to Rust via wrapper objects will not be
 // garbage-collected until the end of the function (used in string.rs when string marshalling is
@@ -857,7 +857,9 @@ macro_rules! impl_ptr_intoabi {
 
 impl_ptr_intoabi!(*const T);
 impl_ptr_intoabi!(*mut T);
+#[cfg(feature = "option_ref_abi")] // disabled because it conflicts with the generic Option<T> impl
 impl_ptr_intoabi!(Option<&'static T>);
+#[cfg(feature = "option_ref_abi")]
 impl_ptr_intoabi!(Option<&'static mut T>);
 
 //

crates/luaffi/src/option.rs

@@ -0,0 +1,84 @@
+use crate::{
+    __internal::{disp, display},
+    Cdef, CdefBuilder, IntoFfi, KEEP_FN, Type, TypeBuilder, TypeType,
+};
+use std::{ffi::c_int, fmt::Display};
+
+#[repr(C)]
+#[allow(non_camel_case_types)]
+pub enum lua_option<T> {
+    None,    // __tag = 0
+    Some(T), // __tag = 1
+}
+
+unsafe impl<T: Type> Type for lua_option<T> {
+    fn name() -> impl Display {
+        display!("option__{}", T::name())
+    }
+
+    fn ty() -> TypeType {
+        TypeType::Aggregate
+    }
+
+    fn cdecl(name: impl Display) -> impl Display {
+        display!("struct {} {name}", Self::name())
+    }
+
+    fn build(b: &mut TypeBuilder) {
+        b.cdef::<Self>();
+    }
+}
+
+unsafe impl<T: Type> Cdef for lua_option<T> {
+    fn build(b: &mut CdefBuilder) {
+        b.field::<c_int>("__tag");
+        (T::ty() != TypeType::Void).then(|| b.field::<T>("__value"));
+    }
+}
+
+unsafe impl<T: IntoFfi> IntoFfi for Option<T> {
+    type Into = lua_option<T::Into>;
+
+    fn convert(self) -> Self::Into {
+        match self {
+            Some(value) => lua_option::Some(T::convert(value)),
+            None => lua_option::None,
+        }
+    }
+
+    fn require_owned() -> bool {
+        // lua_option is only used to transmit information about whether we have a value or not and
+        // is forgotten immediately after use, so there is no need for an owned option
+        false
+    }
+
+    fn postlude(ret: &str) -> impl Display {
+        disp(move |f| {
+            write!(f, "if {ret}.__tag ~= 0 then ")?;
+            match T::Into::ty() {
+                TypeType::Void => write!(f, "{ret} = nil; ")?, // for void options, we don't have a __value
+                TypeType::Primitive => {
+                    // can always copy primitives to stack
+                    write!(f, "{ret} = {ret}.__value; {}", T::postlude(ret))?;
+                }
+                TypeType::Aggregate => {
+                    let ct = T::Into::name();
+                    if T::require_owned() {
+                        // inner value requires ownership; copy it into its own cdata and forget
+                        // option.
+                        write!(f, "{ret} = __new(__ct.{ct}, {ret}.__value); ")?;
+                        write!(f, "{}", T::postlude(ret))?;
+                    } else {
+                        // inner value is a "temporary" like an option itself and doesn't require
+                        // full ownership of itself. we just need to keep the option object alive
+                        // until its postlude completes.
+                        write!(f, "local {ret}_keep = {ret}; {ret} = {ret}.__value; ")?;
+                        write!(f, "do {}end; ", T::postlude(ret))?;
+                        write!(f, "__C.{KEEP_FN}({ret}_keep); ")?; // keep original option alive
+                    }
+                }
+            }
+            write!(f, "else {ret} = nil; end; ")
+        })
+    }
+}

crates/luaffi/src/result.rs

@@ -72,12 +72,12 @@ unsafe impl<T: IntoFfi, E: Display> IntoFfi for Result<T, E> {
                         write!(f, "{ret} = __new(__ct.{ct}, {ret}.__value); ")?;
                         write!(f, "{}", T::postlude(ret))?;
                     } else {
-                        // inner value is a "temporary" itself and doesn't require full ownership of
-                        // itself. we just need to keep the result object alive until its postlude
-                        // completes.
-                        write!(f, "local __{ret} = {ret}; {ret} = {ret}.__value; ")?;
+                        // inner value is a "temporary" like a result itself and doesn't require
+                        // full ownership of itself. we just need to keep the result object alive
+                        // until its postlude completes.
+                        write!(f, "local {ret}_keep = {ret}; {ret} = {ret}.__value; ")?;
                         write!(f, "do {}end; ", T::postlude(ret))?;
-                        write!(f, "__C.{KEEP_FN}(__{ret}); ")?; // keep original result alive
+                        write!(f, "__C.{KEEP_FN}({ret}_keep); ")?; // keep original result alive
                     }
                 }
             }

crates/luaffi/src/string.rs

@@ -4,7 +4,7 @@ use crate::{
 };
 use bstr::{BStr, BString};
 use luaffi_impl::{cdef, metatype};
-use std::{fmt::Display, mem::ManuallyDrop, ptr, slice};
+use std::{fmt::Display, mem::ManuallyDrop, slice};
 
 pub(crate) const IS_UTF8_FN: &str = "luaffi_is_utf8";
 pub(crate) const DROP_BUFFER_FN: &str = "luaffi_drop_buffer";
@@ -42,6 +42,7 @@ impl lua_buf {
         }
     }
 
+    #[cfg(feature = "option_string_abi")]
     pub(crate) fn null() -> Self {
         Self {
             __ptr: ptr::null(),
@@ -71,6 +72,7 @@ impl lua_buffer {
         }
     }
 
+    #[cfg(feature = "option_string_abi")]
     pub(crate) fn null() -> Self {
         Self {
             __ptr: ptr::null_mut(),
@@ -228,6 +230,13 @@ impl_into_via!(&'static str, &'static BStr);
 impl_into_via!(BString, Vec<u8>);
 impl_into_via!(String, BString);
 
+// `Option<String>: From/IntoFfi` isn't implemented because it conflicts with the generic
+// `Option<T>: From/IntoFfi` impl and rust doesn't have specialisation yet (and probably not anytime
+// soon). this is fine for now because we have specialisation for string-like parameters implemented
+// in the #[metatype] macro already, and string returns wrapped in `Option<T>` isn't much additional
+// overhead.
+#[cfg(feature = "option_string_abi")]
+mod impl_option_string {
     macro_rules! impl_optional_from {
         ($ty:ty) => {
             unsafe impl<'s> FromFfi for Option<$ty> {
@@ -281,3 +290,4 @@ impl_optional_into!(&'static str, lua_buf::null());
     impl_optional_into!(Vec<u8>, lua_buffer::null());
     impl_optional_into!(BString, lua_buffer::null());
     impl_optional_into!(String, lua_buffer::null());
+}

src/main.rs

@@ -1,7 +1,9 @@
 use clap::Parser;
 use mimalloc::MiMalloc;
 use owo_colors::OwoColorize;
-use std::{backtrace::Backtrace, fmt::Display, net::SocketAddr, num::NonZero, panic, thread};
+use std::{
+    backtrace::Backtrace, fmt::Display, net::SocketAddr, num::NonZero, panic, process, thread,
+};
 use sysexits::ExitCode;
 
 #[global_allocator]
@@ -20,21 +22,23 @@ fn panic_cb(panic: &panic::PanicHookInfo) {
     };
 
     eprint!(
-        "{}:\n{trace}",
+        "{}\n{trace}",
         format_args!(
             "thread '{}' panicked at {location}: {msg}",
             thread::current().name().unwrap_or("<unnamed>")
         )
         .red()
+        .bold()
     );
 
     eprintln!(
         "{}",
         format_args!(
-            "This is a bug in luby. Please kindly report this at {}.",
+            "luby should never panic. Please kindly report this bug at {}.",
             env!("CARGO_PKG_REPOSITORY")
         )
         .yellow()
+        .bold()
     );
 }
 
@@ -110,17 +114,17 @@ impl Args {
 
 fn exit_err<T, E: Display>(code: ExitCode) -> impl FnOnce(E) -> T {
     move |err| {
-        eprintln!("{}", err.red());
+        eprintln!("{}", err.red().bold());
         code.exit()
     }
 }
 
-fn main() -> Result<(), ExitCode> {
+fn main() {
     panic::set_hook(Box::new(panic_cb));
 
     let args = Args::parse();
     if args.version {
-        return Ok(print_version());
+        return print_version();
     }
 
     init_logger(&args);
@@ -232,13 +236,13 @@ fn parse_jitlib_cmd(s: &str) -> Option<(&str, &str)> {
     }
 }
 
-async fn main_async(args: Args, state: &mut luajit::State) -> Result<(), ExitCode> {
+async fn main_async(args: Args, state: &mut luajit::State) {
     for ref path in args.path {
         let mut s = state.guard();
         let chunk = match std::fs::read(path) {
             Ok(chunk) => chunk,
             Err(err) => {
-                eprintln!("{}", format_args!("{path}: {err}").red());
+                eprintln!("{}", format_args!("{path}: {err}").red().bold());
                 ExitCode::NoInput.exit();
             }
         };
@@ -248,13 +252,11 @@ async fn main_async(args: Args, state: &mut luajit::State) -> Result<(), ExitCod
 
         if let Err(err) = s.call_async(0, 0).await {
             match err.trace() {
-                Some(trace) => eprintln!("{}\n{trace}", err.red()), // runtime error
-                None => eprintln!("{}", err.red()),
+                Some(trace) => eprintln!("{}\n{trace}", err.red().bold()),
+                None => eprintln!("{}", err.red().bold()),
             }
 
-            ExitCode::DataErr.exit();
+            process::exit(1);
         }
     }
-
-    Ok(())
 }

test.lua

@@ -1,6 +1,19 @@
-local ffi = require("ffi")
-local lb = ffi.new("struct lb_core")
+local fs = require("lb:fs")
 
-print(lb)
+-- do
+--   local start = os.clock()
+--   for i = 1, 50000 do
+--     fs:read("crates/luaffi_impl/src/metatype.rs")
+--   end
+--   local finish = os.clock()
+--   print("finish in " .. (finish - start))
+-- end
 
-lb.spawn("")
+do
+  local start = os.clock()
+  for i = 1, 30000 do
+    fs:read_sync("bacon.toml")
+  end
+  local finish = os.clock()
+  print("finish in " .. (finish - start))
+end