Implement eval

boa_engine/src/builtins/eval/mod.rs

@@ -0,0 +1,125 @@
+//! This module implements the global `eval` function.
+//!
+//! The `eval()` function evaluates JavaScript code represented as a string.
+//!
+//! More information:
+//!  - [ECMAScript reference][spec]
+//!  - [MDN documentation][mdn]
+//!
+//! [spec]: https://tc39.es/ecma262/#sec-eval-x
+//! [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/eval
+
+use crate::{
+    builtins::{function::Function, BuiltIn, JsArgs},
+    object::{JsObject, ObjectData},
+    property::Attribute,
+    Context, JsValue,
+};
+use boa_profiler::Profiler;
+use rustc_hash::FxHashSet;
+
+#[derive(Debug, Clone, Copy)]
+pub(crate) struct Eval;
+
+impl BuiltIn for Eval {
+    const NAME: &'static str = "eval";
+
+    const ATTRIBUTE: Attribute = Attribute::READONLY
+        .union(Attribute::NON_ENUMERABLE)
+        .union(Attribute::PERMANENT);
+
+    fn init(context: &mut Context) -> Option<JsValue> {
+        let _timer = Profiler::global().start_event(Self::NAME, "init");
+
+        let object = JsObject::from_proto_and_data(
+            context.intrinsics().constructors().function().prototype(),
+            ObjectData::function(Function::Native {
+                function: Self::eval,
+                constructor: false,
+            }),
+        );
+
+        Some(object.into())
+    }
+}
+
+impl Eval {
+    /// `19.2.1 eval ( x )`
+    ///
+    /// More information:
+    ///  - [ECMAScript reference][spec]
+    ///
+    /// [spec]: https://tc39.es/ecma262/#sec-eval-x
+    fn eval(_: &JsValue, args: &[JsValue], context: &mut Context) -> Result<JsValue, JsValue> {
+        // 1. Return ? PerformEval(x, false, false).
+        Self::perform_eval(args.get_or_undefined(0), false, false, context)
+    }
+
+    /// `19.2.1.1 PerformEval ( x, callerRealm, strictCaller, direct )`
+    ///
+    /// More information:
+    ///  - [ECMAScript reference][spec]
+    ///
+    /// [spec]: https://tc39.es/ecma262/#sec-performeval
+    pub(crate) fn perform_eval(
+        x: &JsValue,
+        direct: bool,
+        strict: bool,
+        context: &mut Context,
+    ) -> Result<JsValue, JsValue> {
+        let x = if let Some(x) = x.as_string() {
+            x.clone()
+        } else {
+            return Ok(x.clone());
+        };
+
+        let parsing_result = context.parse(x.as_bytes()).map_err(|e| e.to_string());
+
+        let statement_list = match parsing_result {
+            Ok(statement_list) => statement_list,
+            Err(e) => return context.throw_syntax_error(e),
+        };
+
+        if direct {
+            context.realm.environments.poison_current();
+            context.realm.compile_env = context.realm.environments.current_compile_environment();
+            let environments_len = context.realm.environments.len();
+
+            let mut vars = FxHashSet::default();
+            statement_list.var_declared_names_new(&mut vars);
+            if let Some(name) = context
+                .realm
+                .environments
+                .has_lex_binding_until_function_environment(&vars)
+            {
+                return context.throw_syntax_error(format!("variable declaration {} in eval function already exists as lexically declaration", context.interner().resolve_expect(name)));
+            }
+
+            let code_block = context.compile_with_new_declarative(&statement_list, strict)?;
+            context
+                .realm
+                .environments
+                .extend_outer_function_environment();
+            let result = context.execute(code_block);
+
+            context.realm.environments.truncate(environments_len);
+
+            result
+        } else {
+            context.realm.environments.poison_all();
+
+            let environments = context.realm.environments.pop_to_global();
+            let environments_len = context.realm.environments.len();
+
+            context.realm.compile_env = context.realm.environments.current_compile_environment();
+
+            let code_block = context.compile_with_new_declarative(&statement_list, false)?;
+            let result = context.execute(code_block);
+
+            context.realm.environments.truncate(environments_len);
+            context.realm.environments.extend(environments);
+
+            result
+        }
+    }
+}

boa_engine/src/builtins/mod.rs

@@ -9,6 +9,7 @@ pub mod console;
 pub mod dataview;
 pub mod date;
 pub mod error;
+pub mod eval;
 pub mod function;
 pub mod generator;
 pub mod generator_function;
@@ -41,6 +42,7 @@ pub(crate) use self::{
         AggregateError, Error, EvalError, RangeError, ReferenceError, SyntaxError, TypeError,
         UriError,
     },
+    eval::Eval,
     function::BuiltInFunctionObject,
     global_this::GlobalThis,
     infinity::Infinity,
@@ -152,6 +154,7 @@ pub fn init(context: &mut Context) {
         DataView,
         Map,
         Number,
+        Eval,
         Set,
         String,
         RegExp,