Introduce the javy-config crate

This commit prepares the terrain to bridge the gap in configurability
between the CLI and Javy, the crate.
The intention behind introducing a new crate is to:

* Reduce code duplication and sync the options between the CLI and the
  core crate.
* Make it easy to pass the options into WebAssemlby by using bitflags.

This PR doesn't introduce any new functionality. A follow up PR will
include new commands in the CLI which will make use of the share
configuration.

Cargo.toml

@@ -7,6 +7,7 @@ members = [
   "crates/core",
   "crates/cli",
   "crates/javy-test-macros",
+  "crates/javy-config",
 ]
 resolver = "2"
 
@@ -23,7 +24,9 @@ wasmtime-wasi = "19"
 wasi-common = "19"
 anyhow = "1.0"
 once_cell = "1.19"
+bitflags = "2.5.0"
 javy = { path = "crates/javy", version = "3.0.0-alpha.1" }
+javy-config = { path = "crates/javy-config" }
 
 [profile.release]
 lto = true

crates/core/Cargo.toml

@@ -17,6 +17,7 @@ crate-type = ["cdylib"]
 anyhow = { workspace = true }
 javy = { workspace = true, features = ["export_alloc_fns", "json"] }
 once_cell = { workspace = true }
+javy-config = { workspace = true }
 
 [features]
 experimental_event_loop = []

crates/core/src/lib.rs

@@ -1,5 +1,6 @@
 use anyhow::anyhow;
 use javy::Runtime;
+use javy_config::Config;
 use once_cell::sync::OnceCell;
 use std::slice;
 use std::str;
@@ -16,7 +17,7 @@ static mut RUNTIME: OnceCell<Runtime> = OnceCell::new();
 /// Used by Wizer to preinitialize the module.
 #[export_name = "wizer.initialize"]
 pub extern "C" fn init() {
-    let runtime = runtime::new_runtime().unwrap();
+    let runtime = runtime::new(Config::all()).unwrap();
     unsafe {
         RUNTIME
             .set(runtime)
@@ -43,7 +44,7 @@ pub extern "C" fn init() {
 #[export_name = "compile_src"]
 pub unsafe extern "C" fn compile_src(js_src_ptr: *const u8, js_src_len: usize) -> *const u32 {
     // Use fresh runtime to avoid depending on Wizened runtime
-    let runtime = runtime::new_runtime().unwrap();
+    let runtime = runtime::new(Config::all()).unwrap();
     let js_src = str::from_utf8(slice::from_raw_parts(js_src_ptr, js_src_len)).unwrap();
 
     let bytecode = runtime

crates/core/src/main.rs

@@ -6,6 +6,7 @@ use std::slice;
 use std::str;
 use std::string::String;
 
+use javy_config::Config;
 mod execution;
 mod runtime;
 
@@ -18,7 +19,7 @@ static mut BYTECODE: OnceCell<Vec<u8>> = OnceCell::new();
 pub extern "C" fn init() {
     let _wasm_ctx = WasmCtx::new();
 
-    let runtime = runtime::new_runtime().unwrap();
+    let runtime = runtime::new(Config::all()).unwrap();
 
     let mut contents = String::new();
     io::stdin().read_to_string(&mut contents).unwrap();

crates/core/src/runtime.rs

@@ -1,14 +1,17 @@
 use anyhow::Result;
 use javy::{Config, Runtime};
+use javy_config::Config as SharedConfig;
 
-pub(crate) fn new_runtime() -> Result<Runtime> {
+pub(crate) fn new(shared_config: SharedConfig) -> Result<Runtime> {
     let mut config = Config::default();
     let config = config
-        .text_encoding(true)
-        .redirect_stdout_to_stderr(true)
-        .javy_stream_io(true)
-        .override_json_parse_and_stringify(true)
-        .javy_json(true);
+        .text_encoding(shared_config.contains(SharedConfig::TEXT_ENCODING))
+        .redirect_stdout_to_stderr(shared_config.contains(SharedConfig::REDIRECT_STDOUT_TO_STDERR))
+        .javy_stream_io(shared_config.contains(SharedConfig::JAVY_STREAM_IO))
+        .override_json_parse_and_stringify(
+            shared_config.contains(SharedConfig::OVERRIDE_JSON_PARSE_AND_STRINGIFY),
+        )
+        .javy_json(shared_config.contains(SharedConfig::JAVY_JSON));
 
     Runtime::new(std::mem::take(config))
 }

crates/javy-config/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "javy-config"
+version.workspace = true
+authors.workspace = true
+edition.workspace = true
+license.workspace = true
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+bitflags = { workspace = true }

crates/javy-config/README.md

@@ -0,0 +1,3 @@
+# Shared Configuration for Javy
+
+See `src/lib.rs` for more details.

crates/javy-config/src/lib.rs

@@ -0,0 +1,34 @@
+//! Shared Configuration for Javy.
+//!
+//! This crate serves as a central place to facilitate configuration sharing
+//! between the Javy CLI and the Javy crate. It addresses the challenge of
+//! passing configuration settings in environments where the Javy CLI commands
+//! predominantly execute WebAssembly.
+//!
+//! The purpose of this crate is to consolidate configuration parameters,
+//! ensuring consistent and accessible settings across both the CLI and the
+//! crate. This approach simplifies the management of configuration settings and
+//! enhances the integration between different components of the Javy ecosystem.
+//!
+//! Currently, this crate includes only a subset of the available configuration
+//! options. The objective is to eventually encompass all configurable
+//! parameters found in [javy::Config].
+//!
+//! The selection of the current configuration options was influenced by the
+//! need to override non-standard defaults typically set during CLI invocations.
+//! These defaults often do not align with the preferences of the CLI users.
+//!
+//! In gneneral this crate should be treated as an internal detail and
+//! a contract between the CLI and the Javy crate.
+
+use bitflags::bitflags;
+
+bitflags! {
+    pub struct Config: u32 {
+        const OVERRIDE_JSON_PARSE_AND_STRINGIFY = 1;
+        const JAVY_JSON = 1 << 1;
+        const JAVY_STREAM_IO = 1 << 1;
+        const REDIRECT_STDOUT_TO_STDERR = 1 << 2;
+        const TEXT_ENCODING = 1 << 3;
+    }
+}

crates/javy/Cargo.toml

@@ -19,7 +19,7 @@ rmp-serde = { version = "^1.3", optional = true }
 # TODO: cargo doesn't seem to pickup the fact that quickcheck is only used for
 # tests.
 quickcheck = "1"
-bitflags = "2.5.0"
+bitflags = { workspace = true }
 fastrand = "2.1.0"
 simd-json = { version = "0.13.10", optional = true, default-features = false, features = ["big-int-as-float", "serde_impl"] }