Add method of overriding stdout to client console for gmcl modules

Cargo.lock

@@ -144,7 +144,7 @@ dependencies = [
  "fn_abi",
  "fn_has_this",
  "fn_type_alias",
- "gmod-macros 1.0.1",
+ "gmod-macros 1.0.2",
  "gmserverplugin",
  "lazy_static",
  "libloading",
@@ -165,7 +165,7 @@ dependencies = [
 
 [[package]]
 name = "gmod-macros"
-version = "1.0.1"
+version = "1.0.2"
 dependencies = [
  "proc-macro2",
  "quote",

gmod-macros/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "gmod-macros"
-version = "1.0.1"
+version = "1.0.2"
 authors = ["William Venner <william@venner.io>"]
 edition = "2018"
 license = "MIT"

gmod-macros/src/lib.rs

@@ -6,7 +6,7 @@ extern crate quote;
 
 use proc_macro::TokenStream;
 use quote::ToTokens;
-use syn::{ReturnType, ItemFn};
+use syn::{ReturnType, ItemFn, Attribute};
 
 fn check_lua_function(input: &mut ItemFn) {
 	assert!(input.sig.asyncness.is_none(), "Cannot be async");
@@ -17,11 +17,22 @@ fn check_lua_function(input: &mut ItemFn) {
 	input.sig.abi = Some(syn::parse_quote!(extern "C-unwind"));
 }
 
+fn no_mangle(item_fn: &mut ItemFn) {
+	item_fn.attrs.push(Attribute {
+		path: parse_quote!(no_mangle),
+		tokens: proc_macro2::TokenStream::new(),
+		style: syn::AttrStyle::Outer,
+		pound_token: Default::default(),
+		bracket_token: Default::default(),
+	});
+}
+
 #[proc_macro_attribute]
 pub fn gmod13_open(_attr: TokenStream, tokens: TokenStream) -> TokenStream {
 	let mut input = parse_macro_input!(tokens as ItemFn);
 	check_lua_function(&mut input);
 	input.block.stmts.insert(0, syn::parse2(quote!(#[allow(unused_unsafe)] unsafe { ::gmod::lua::load() })).unwrap());
+	no_mangle(&mut input);
 	input.into_token_stream().into()
 }
 
@@ -29,6 +40,7 @@ pub fn gmod13_open(_attr: TokenStream, tokens: TokenStream) -> TokenStream {
 pub fn gmod13_close(_attr: TokenStream, tokens: TokenStream) -> TokenStream {
 	let mut input = parse_macro_input!(tokens as ItemFn);
 	check_lua_function(&mut input);
+	no_mangle(&mut input);
 	input.into_token_stream().into()
 }
 

gmod/Cargo.toml

@@ -13,9 +13,10 @@ categories = ["api-bindings", "external-ffi-bindings", "game-development", "deve
 default = ["hax"]
 hax = ["ctor", "skidscan", "detour", "fn_type_alias", "fn_abi", "cfg_table", "null_fn", "fn_has_this"]
 server-plugin = ["gmserverplugin"]
+gmcl = []
 
 [dependencies]
-gmod-macros = { version = "1.0.1", path = "../gmod-macros" }
+gmod-macros = { version = "1.0.2", path = "../gmod-macros" }
 gmserverplugin = { version = "1", optional = true }
 
 libloading = "0"

gmod/src/gmcl.rs

@@ -0,0 +1,51 @@
+use std::{sync::{Arc, Mutex, TryLockError}, time::Duration, os::raw::c_char};
+
+/// This function will **permanently** redirect stdout to the client console.
+///
+/// This allows for `println!()` and friends to print to the client console.
+pub fn override_stdout() {
+	unsafe {
+		let (_lib, _path) = crate::open_library!("tier0").expect("Failed to open tier0.dll");
+
+		#[allow(non_snake_case)]
+		let ConMsg: extern "C" fn(*const c_char, ...) = *{
+			#[cfg(target_os = "windows")] {
+				_lib.get({
+					#[cfg(all(target_os = "windows", target_pointer_width = "64"))] {
+						b"?ConMsg@@YAXPEBDZZ\0"
+					}
+					#[cfg(all(target_os = "windows", target_pointer_width = "32"))] {
+						b"?ConMsg@@YAXPBDZZ\0"
+					}
+				})
+			}
+			#[cfg(target_os = "linux")] {
+				_lib.get(b"ConMsg\0").or_else(|_| _lib.get(b"_Z6ConMsgPKcz\0"))
+			}
+		}.expect("Failed to find ConMsg");
+
+		let output_buf = Arc::new(Mutex::new(Vec::new()));
+		let output_buf_ref = output_buf.clone();
+
+		// This is actually a really dumb implementation, but appears to be the only way, unfortunately.
+		std::thread::spawn(move || loop {
+			match output_buf.try_lock() {
+				Ok(mut data) => if !data.is_empty() {
+					data.push(0); // cheeky
+					ConMsg(data.as_ptr() as *const i8);
+
+					data.truncate(0);
+				},
+				Err(TryLockError::Poisoned(err)) => panic!("{}", err),
+				Err(TryLockError::WouldBlock) => {
+					std::hint::spin_loop();
+					std::thread::yield_now();
+					continue
+				}
+			}
+			std::thread::sleep(Duration::from_millis(250));
+		});
+
+		std::io::set_output_capture(Some(output_buf_ref));
+	};
+}

gmod/src/lib.rs

@@ -1,6 +1,8 @@
 #![feature(c_unwind)]
 #![feature(thread_id_value)]
 
+#![cfg_attr(feature = "gmcl", feature(internal_output_capture))]
+
 pub use cstr;
 pub use libloading;
 pub use gmod_macros::*;
@@ -38,6 +40,10 @@ pub mod userdata;
 /// Net library helpers
 pub mod net;
 
+/// Clientside module helpers
+#[cfg(feature = "gmcl")]
+pub mod gmcl;
+
 /// Returns whether this client is running the x86-64 branch
 pub fn is_x86_64() -> bool {
 	#[cfg(target_pointer_width = "64")] {

gmod/src/lua/import.rs

@@ -74,10 +74,10 @@ impl LuaError {
 }
 
 #[cfg_attr(not(debug_assertions), repr(transparent))]
-pub struct LuaSharedInterface(UnsafeCell<*mut LuaShared>, #[cfg(debug_assertions)] AtomicI64);
+pub struct LuaSharedInterface(pub(crate) UnsafeCell<*mut LuaShared>, #[cfg(debug_assertions)] AtomicI64);
 impl LuaSharedInterface {
 	#[cfg(debug_assertions)]
-	fn debug_assertions(&self) {
+	pub(crate) fn debug_assertions(&self) {
 		assert!(!unsafe { *self.0.get() }.is_null(), "The Lua state has not been initialized yet. Add `#[gmod::gmod13_open]` to your module's gmod13_open function to fix this. You can also manually load the Lua state with `gmod::load_lua_state()` or `gmod::set_lua_state(*mut c_void)`");
 
 		let thread_id = u64::from(std::thread::current().id().as_u64()) as i64;