Merge pull request #5 from Icemic/module_loader_result

Better error handling of module loader

Author: Icemic

Cargo.toml

@@ -11,7 +11,7 @@ repository = "https://github.com/Icemic/quickjs-rusty"
 version = "0.7.0"
 
 [package.metadata.docs.rs]
-features = ["chrono", "bigint", "log"]
+features = ["chrono", "bigint"]
 
 [features]
 bigint = ["num-bigint", "num-traits"]
@@ -22,7 +22,7 @@ serde = ["thiserror", "dep:serde"]
 anyhow = {version = "1"}
 chrono = {version = "0.4.7", optional = true}
 libquickjs-ng-sys = {version = "^0.7.1", path = "./libquickjs-sys"}
-log = {version = "0.4.8", optional = true}
+log = "0.4"
 num-bigint = {version = "0.4.4", optional = true}
 num-traits = {version = "0.2.0", optional = true}
 serde = {version = "1", features = ["derive"], optional = true}

examples/eval_module.rs

@@ -1,3 +1,4 @@
+use anyhow::Result;
 use quickjs_rusty::Context;
 
 struct Custom {
@@ -31,20 +32,20 @@ pub fn main() {
     println!("js: 1 + 2 = {:?}", value);
 }
 
-fn module_loader(module_name: &str, opaque: *mut std::ffi::c_void) -> String {
+fn module_loader(module_name: &str, opaque: *mut std::ffi::c_void) -> Result<String> {
     println!("module_loader: {:?}", module_name);
     let custom = unsafe { &*(opaque as *mut Custom) };
     assert!(custom.foo == 123);
-    "export function add(a, b) { return a + b; }; console.log('module loaded.')".to_string()
+    Ok("export function add(a, b) { return a + b; }; console.log('module loaded.')".to_string())
 }
 
 fn module_normalize(
     module_base_name: &str,
     module_name: &str,
     opaque: *mut std::ffi::c_void,
-) -> String {
+) -> Result<String> {
     println!("module_normalize: {:?} {:?}", module_base_name, module_name);
     let custom = unsafe { &*(opaque as *mut Custom) };
     assert!(custom.foo == 123);
-    module_name.to_string()
+    Ok(module_name.to_string())
 }

src/errors/execution_error.rs

@@ -30,7 +30,7 @@ impl fmt::Display for ExecutionError {
             Internal(e) => write!(f, "Internal error: {}", e),
             Exception(e) => {
                 if e.is_string() {
-                    write!(f, "{:?}", e.to_string().unwrap())
+                    write!(f, "{}", e.to_string().unwrap())
                 } else {
                     write!(f, "JS Exception: {:?}", e)
                 }

src/module_loader.rs

@@ -1,12 +1,17 @@
-use std::ffi::{c_char, c_void, CStr};
+use std::ffi::{c_char, c_void, CStr, CString};
 use std::ptr::null_mut;
 
+use anyhow::Result;
 use libquickjs_ng_sys as q;
 
 use super::compile::compile_module;
 
-pub type JSModuleLoaderFunc = Box<dyn Fn(&str, *mut c_void) -> String>;
-pub type JSModuleNormalizeFunc = Box<dyn Fn(&str, &str, *mut c_void) -> String>;
+/// Custom module loader function, passes (module_name, opaque) and returns module code
+/// If the module code is not found, return None
+pub type JSModuleLoaderFunc = Box<dyn Fn(&str, *mut c_void) -> Result<String>>;
+/// Custom module normalize function, passes (module_base_name, module_name, opaque)
+/// and returns normalized module name (or None if not found)
+pub type JSModuleNormalizeFunc = Box<dyn Fn(&str, &str, *mut c_void) -> Result<String>>;
 
 pub struct ModuleLoader {
     pub loader: JSModuleLoaderFunc,
@@ -23,17 +28,22 @@ pub unsafe extern "C" fn js_module_loader(
     let opaque = wrapper.opaque;
     let loader = &wrapper.loader;
 
-    let module_name = CStr::from_ptr(module_name).to_str().unwrap();
-    let module_code = loader(module_name, opaque);
+    let module_name = CStr::from_ptr(module_name).to_string_lossy().to_string();
+    let module_code = match loader(&module_name, opaque) {
+        Ok(v) => v,
+        Err(err) => {
+            throw_internal_error(ctx, &err.to_string());
+            return null_mut() as *mut q::JSModuleDef;
+        }
+    };
 
-    match compile_module(ctx, &module_code, module_name) {
+    match compile_module(ctx, &module_code, &module_name) {
         Ok(v) => {
             let module_def = q::JS_Ext_GetPtr(v.value);
-            // q::JS_DupValue(wrapper.context, v.value);
             module_def as *mut q::JSModuleDef
         }
         Err(e) => {
-            eprintln!("compile module error: {:?}", e);
+            throw_internal_error(ctx, &e.to_string());
             null_mut() as *mut q::JSModuleDef
         }
     }
@@ -54,7 +64,13 @@ pub unsafe extern "C" fn js_module_normalize(
 
     if let Some(module_normalize_func) = normalize {
         let mut normalized_module_name =
-            module_normalize_func(module_base_name, module_name, opaque);
+            match module_normalize_func(module_base_name, module_name, opaque) {
+                Ok(v) => v,
+                Err(err) => {
+                    throw_internal_error(ctx, &err.to_string());
+                    return null_mut() as *mut c_char;
+                }
+            };
         normalized_module_name.push('\0');
         let m = q::js_malloc(ctx, normalized_module_name.len());
         std::ptr::copy(
@@ -64,7 +80,15 @@ pub unsafe extern "C" fn js_module_normalize(
         );
         m as *mut c_char
     } else {
-        eprintln!("module normalize func not set");
+        log::warn!("module normalize func not set");
         null_mut() as *mut c_char
     }
 }
+
+#[inline]
+fn throw_internal_error(ctx: *mut q::JSContext, err: &str) {
+    let err = CString::new(err).unwrap();
+    unsafe {
+        q::JS_ThrowInternalError(ctx, err.as_ptr() as *const i8);
+    }
+}