Fix builds.

CHANGELOG.md

@@ -8,7 +8,9 @@ Bug fixes
 ---------
 
 * Variable resolver now correctly resolves variables that are captured in a closure.
-* `NativeCallContext<'_>` (with a lifetime parameter) now parses correctly in the `#[export_module]` macro. This is to allow for `rust_2018_idioms` lints.
+* `NativeCallContext<'_>` (with a lifetime parameter) now parses correctly in the `#[export_module]`
+  macro. This is to allow for `rust_2018_idioms` lints (thanks [`@ltabis`](https://github.com/ltabis) [864](https://github.com/rhaiscript/rhai/issues/864)).
+* The `sync` feature now works properly in `no-std` builds (thanks [`@misssonder`](https://github.com/misssonder) [874](https://github.com/rhaiscript/rhai/pull/874)).
 
 New features
 ------------

benches/eval_array.rs

@@ -67,7 +67,7 @@ fn bench_eval_array_loop(bench: &mut Bencher) {
     let script = "
             let list = [];
 
-            for i in 0..10_000 {
+            for i in 0..1_888 {
                 list.push(i);
             }
 

benches/eval_expression.rs

@@ -125,7 +125,7 @@ fn bench_eval_deeply_nested(bench: &mut Bencher) {
 fn bench_eval_loop_number(bench: &mut Bencher) {
     let script = "
         let s = 0;
-        for x in 0..10000 {
+        for x in 0..1_888 {
             s += 1;
         }
     ";
@@ -142,7 +142,7 @@ fn bench_eval_loop_number(bench: &mut Bencher) {
 fn bench_eval_loop_strings_build(bench: &mut Bencher) {
     let script = r#"
         let s;
-        for x in 0..10000 {
+        for x in 0..1_888 {
             s = "hello, world!" + "hello, world!";
         }
     "#;
@@ -159,7 +159,7 @@ fn bench_eval_loop_strings_build(bench: &mut Bencher) {
 fn bench_eval_loop_strings_no_build(bench: &mut Bencher) {
     let script = r#"
         let s;
-        for x in 0..10000 {
+        for x in 0..1_888 {
             s = "hello" + "";
         }
     "#;

codegen/src/module.rs

@@ -1,9 +1,9 @@
 use quote::{quote, ToTokens};
 use syn::{parse::Parse, parse::ParseStream};
 
 #[cfg(no_std)]
 use core::mem;
 #[cfg(not(no_std))]
 use std::mem;
 
 use std::borrow::Cow;
@@ -139,17 +139,13 @@
             for item in &*content {
                 if let syn::Item::Const(syn::ItemConst {
                     vis: syn::Visibility::Public(..),
-                    ref expr,
                     ident,
                     attrs,
-                    ty,
                     ..
                 }) = item
                 {
                     consts.push(ExportedConst {
                         name: ident.to_string(),
-                        typ: ty.clone(),
-                        expr: expr.as_ref().clone(),
                         cfg_attrs: crate::attrs::collect_cfg_attr(attrs),
                     })
                 }

codegen/src/rhai_module.rs

@@ -13,8 +13,6 @@ use crate::module::Module;
 #[derive(Debug)]
 pub struct ExportedConst {
     pub name: String,
-    pub typ: Box<syn::Type>,
-    pub expr: syn::Expr,
     pub cfg_attrs: Vec<syn::Attribute>,
 }
 

codegen/src/test/module.rs

@@ -183,10 +183,6 @@ mod module_tests {
         assert!(item_mod.consts().is_empty());
         assert_eq!(item_mod.sub_modules().len(), 1);
         assert_eq!(&item_mod.sub_modules()[0].consts()[0].name, "MYSTIC_NUMBER");
-        assert_eq!(
-            item_mod.sub_modules()[0].consts()[0].expr,
-            syn::parse2::<syn::Expr>(quote! { 42 }).unwrap()
-        );
     }
 
     #[test]
@@ -244,10 +240,6 @@ mod module_tests {
         assert!(item_mod.fns().is_empty());
         assert_eq!(item_mod.consts().len(), 1);
         assert_eq!(&item_mod.consts()[0].name, "MYSTIC_NUMBER");
-        assert_eq!(
-            item_mod.consts()[0].expr,
-            syn::parse2::<syn::Expr>(quote! { 42 }).unwrap()
-        );
     }
 
     #[test]

no_std/no_std_test/Cargo.toml

@@ -10,8 +10,8 @@ homepage = "https://github.com/rhaiscript/rhai/tree/no_std/no_std_test"
 repository = "https://github.com/rhaiscript/rhai"
 
 [dependencies]
-rhai = { path = "../../", features = ["no_std"], default_features = false }
-wee_alloc = { version = "0.4.5", default_features = false }
+rhai = { path = "../../", features = ["no_std", "sync"], default-features = false }
+wee_alloc = { version = "0.4.5", default-features = false }
 
 [profile.dev]
 panic = "abort"

src/api/limits.rs

@@ -35,8 +35,6 @@ pub mod default_limits {
     /// Not available under `no_function`.
     #[cfg(not(feature = "no_function"))]
     pub const MAX_FUNCTION_EXPR_DEPTH: usize = 32;
-    /// Maximum number of strings interned.
-    pub const MAX_STRINGS_INTERNED: usize = 1024;
 }
 
 /// A type containing all the limits imposed by the [`Engine`].

src/func/native.rs

@@ -529,12 +529,36 @@ pub fn locked_read<T>(value: &Locked<T>) -> Option<LockGuard<T>> {
     return value.try_borrow().ok();
 
     #[cfg(feature = "sync")]
-    #[cfg(feature = "unchecked")]
-    return value.read().ok();
+    #[cfg(not(feature = "no_std"))]
+    {
+        #[cfg(feature = "unchecked")]
+        return value.read().ok();
+
+        #[cfg(not(feature = "unchecked"))]
+        {
+            // Spin-lock for a short while before giving up
+            for _ in 0..5 {
+                match value.try_read() {
+                    Ok(guard) => return Some(guard),
+                    Err(std::sync::TryLockError::WouldBlock) => {
+                        std::thread::sleep(std::time::Duration::from_millis(10))
+                    }
+                    Err(_) => return None,
+                }
+            }
+
+            return None;
+        }
+    }
 
     #[cfg(feature = "sync")]
-    #[cfg(not(feature = "unchecked"))]
-    return value.try_read();
+    #[cfg(feature = "no_std")]
+    {
+        #[cfg(feature = "unchecked")]
+        return Some(value.read());
+        #[cfg(not(feature = "unchecked"))]
+        return value.try_read();
+    }
 }
 
 /// _(internals)_ Lock a [`Locked`] resource for mutable access.
@@ -547,12 +571,36 @@ pub fn locked_write<T>(value: &Locked<T>) -> Option<LockGuardMut<T>> {
     return value.try_borrow_mut().ok();
 
     #[cfg(feature = "sync")]
-    #[cfg(feature = "unchecked")]
-    return value.write().ok();
+    #[cfg(not(feature = "no_std"))]
+    {
+        #[cfg(feature = "unchecked")]
+        return value.write().ok();
+
+        #[cfg(not(feature = "unchecked"))]
+        {
+            // Spin-lock for a short while before giving up
+            for _ in 0..5 {
+                match value.try_write() {
+                    Ok(guard) => return Some(guard),
+                    Err(std::sync::TryLockError::WouldBlock) => {
+                        std::thread::sleep(std::time::Duration::from_millis(10))
+                    }
+                    Err(_) => return None,
+                }
+            }
+
+            return None;
+        }
+    }
 
     #[cfg(feature = "sync")]
-    #[cfg(not(feature = "unchecked"))]
-    return value.try_write();
+    #[cfg(feature = "no_std")]
+    {
+        #[cfg(feature = "unchecked")]
+        return Some(value.write());
+        #[cfg(not(feature = "unchecked"))]
+        return value.try_write();
+    }
 }
 
 /// General Rust function trail object.

src/types/dynamic.rs

@@ -1701,6 +1701,10 @@ impl Dynamic {
                 #[cfg(not(feature = "sync"))]
                 Ok(value) => value.into_inner().flatten(),
                 #[cfg(feature = "sync")]
+                #[cfg(not(feature = "no_std"))]
+                Ok(value) => value.into_inner().unwrap().flatten(),
+                #[cfg(feature = "sync")]
+                #[cfg(feature = "no_std")]
                 Ok(value) => value.into_inner().flatten(),
                 // If there are outstanding references, return a cloned copy
                 Err(cell) => {