Implement for..in (#976)

* Implement for..in

* Fix code styling issue

* Add break and continue with label

* Add break and continue for while and do-while

* Add unit tests

* Fix formatting

* Split node ForInOfLoop into ForInLoop and ForOfLoop

* Fix issues in ForInOfLoop node splitting

* Merge with master branch

Co-authored-by: tofpie <tofpie@users.noreply.github.com>

boa/src/builtins/iterable/mod.rs

@@ -1,6 +1,7 @@
 use crate::{
     builtins::string::string_iterator::StringIterator,
     builtins::ArrayIterator,
+    builtins::ForInIterator,
     builtins::MapIterator,
     object::{GcObject, ObjectInitializer},
     property::{Attribute, DataDescriptor},
@@ -13,6 +14,7 @@ pub struct IteratorPrototypes {
     array_iterator: GcObject,
     string_iterator: GcObject,
     map_iterator: GcObject,
+    for_in_iterator: GcObject,
 }
 
 impl IteratorPrototypes {
@@ -28,9 +30,12 @@ impl IteratorPrototypes {
             string_iterator: StringIterator::create_prototype(context, iterator_prototype.clone())
                 .as_object()
                 .expect("String Iterator Prototype is not an object"),
-            map_iterator: MapIterator::create_prototype(context, iterator_prototype)
+            map_iterator: MapIterator::create_prototype(context, iterator_prototype.clone())
                 .as_object()
                 .expect("Map Iterator Prototype is not an object"),
+            for_in_iterator: ForInIterator::create_prototype(context, iterator_prototype)
+                .as_object()
+                .expect("For In Iterator Prototype is not an object"),
         }
     }
 
@@ -49,9 +54,15 @@ impl IteratorPrototypes {
         self.string_iterator.clone()
     }
 
+    #[inline]
     pub fn map_iterator(&self) -> GcObject {
         self.map_iterator.clone()
     }
+
+    #[inline]
+    pub fn for_in_iterator(&self) -> GcObject {
+        self.for_in_iterator.clone()
+    }
 }
 
 /// CreateIterResultObject( value, done )
@@ -110,7 +121,7 @@ pub struct IteratorRecord {
 }
 
 impl IteratorRecord {
-    fn new(iterator_object: Value, next_function: Value) -> Self {
+    pub fn new(iterator_object: Value, next_function: Value) -> Self {
         Self {
             iterator_object,
             next_function,

boa/src/builtins/mod.rs

@@ -37,6 +37,7 @@ pub(crate) use self::{
     math::Math,
     nan::NaN,
     number::Number,
+    object::for_in_iterator::ForInIterator,
     object::Object as BuiltInObjectObject,
     regexp::RegExp,
     string::String,

boa/src/builtins/object/for_in_iterator.rs

@@ -0,0 +1,145 @@
+use crate::property::PropertyKey;
+use crate::value::RcString;
+use crate::{
+    builtins::{function::make_builtin_fn, iterable::create_iter_result_object},
+    gc::{Finalize, Trace},
+    object::ObjectData,
+    property::{Attribute, DataDescriptor},
+    BoaProfiler, Context, Result, Value,
+};
+use rustc_hash::FxHashSet;
+use std::collections::VecDeque;
+
+/// The ForInIterator object represents an iteration over some specific object.
+/// It implements the iterator protocol.
+///
+/// More information:
+///  - [ECMAScript reference][spec]
+///
+/// [spec]: https://tc39.es/ecma262/#sec-for-in-iterator-objects
+#[derive(Debug, Clone, Finalize, Trace)]
+pub struct ForInIterator {
+    object: Value,
+    visited_keys: FxHashSet<RcString>,
+    remaining_keys: VecDeque<RcString>,
+    object_was_visited: bool,
+}
+
+impl ForInIterator {
+    pub(crate) const NAME: &'static str = "ForInIterator";
+
+    fn new(object: Value) -> Self {
+        ForInIterator {
+            object,
+            visited_keys: FxHashSet::default(),
+            remaining_keys: VecDeque::default(),
+            object_was_visited: false,
+        }
+    }
+
+    /// CreateForInIterator( object )
+    ///
+    /// Creates a new iterator over the given object.
+    ///
+    /// More information:
+    ///  - [ECMA reference][spec]
+    ///
+    /// [spec]: https://tc39.es/ecma262/#sec-createforiniterator
+    pub(crate) fn create_for_in_iterator(context: &Context, object: Value) -> Result<Value> {
+        let for_in_iterator = Value::new_object(context);
+        for_in_iterator.set_data(ObjectData::ForInIterator(Self::new(object)));
+        for_in_iterator
+            .as_object()
+            .expect("for in iterator object")
+            .set_prototype_instance(context.iterator_prototypes().for_in_iterator().into());
+        Ok(for_in_iterator)
+    }
+
+    /// %ForInIteratorPrototype%.next( )
+    ///
+    /// Gets the next result in the object.
+    ///
+    /// More information:
+    ///  - [ECMA reference][spec]
+    ///
+    /// [spec]: https://tc39.es/ecma262/#sec-%foriniteratorprototype%.next
+    pub(crate) fn next(this: &Value, _: &[Value], context: &mut Context) -> Result<Value> {
+        if let Value::Object(ref o) = this {
+            let mut for_in_iterator = o.borrow_mut();
+            if let Some(iterator) = for_in_iterator.as_for_in_iterator_mut() {
+                let mut object = iterator.object.to_object(context)?;
+                loop {
+                    if !iterator.object_was_visited {
+                        let keys = object.own_property_keys();
+                        for k in keys {
+                            match k {
+                                PropertyKey::String(ref k) => {
+                                    iterator.remaining_keys.push_back(k.clone());
+                                }
+                                PropertyKey::Index(i) => {
+                                    iterator.remaining_keys.push_back(i.to_string().into());
+                                }
+                                _ => {}
+                            }
+                        }
+                        iterator.object_was_visited = true;
+                    }
+                    while let Some(r) = iterator.remaining_keys.pop_front() {
+                        if !iterator.visited_keys.contains(&r) {
+                            if let Some(desc) =
+                                object.get_own_property(&PropertyKey::from(r.clone()))
+                            {
+                                iterator.visited_keys.insert(r.clone());
+                                if desc.enumerable() {
+                                    return Ok(create_iter_result_object(
+                                        context,
+                                        Value::from(r.to_string()),
+                                        false,
+                                    ));
+                                }
+                            }
+                        }
+                    }
+                    match object.prototype_instance().to_object(context) {
+                        Ok(o) => {
+                            object = o;
+                        }
+                        _ => {
+                            return Ok(create_iter_result_object(context, Value::undefined(), true))
+                        }
+                    }
+                    iterator.object = Value::from(object.clone());
+                    iterator.object_was_visited = false;
+                }
+            } else {
+                context.throw_type_error("`this` is not a ForInIterator")
+            }
+        } else {
+            context.throw_type_error("`this` is not an ForInIterator")
+        }
+    }
+
+    /// Create the %ArrayIteratorPrototype% object
+    ///
+    /// More information:
+    ///  - [ECMA reference][spec]
+    ///
+    /// [spec]: https://tc39.es/ecma262/#sec-%foriniteratorprototype%-object
+    pub(crate) fn create_prototype(context: &mut Context, iterator_prototype: Value) -> Value {
+        let _timer = BoaProfiler::global().start_event(Self::NAME, "init");
+
+        // Create prototype
+        let for_in_iterator = Value::new_object(context);
+        make_builtin_fn(Self::next, "next", &for_in_iterator, 0, context);
+        for_in_iterator
+            .as_object()
+            .expect("for in iterator prototype object")
+            .set_prototype_instance(iterator_prototype);
+
+        let to_string_tag = context.well_known_symbols().to_string_tag_symbol();
+        let to_string_tag_property =
+            DataDescriptor::new("For In Iterator", Attribute::CONFIGURABLE);
+        for_in_iterator.set_property(to_string_tag, to_string_tag_property);
+        for_in_iterator
+    }
+}

boa/src/builtins/object/mod.rs

@@ -23,6 +23,7 @@ use crate::{
     BoaProfiler, Context, Result,
 };
 
+pub mod for_in_iterator;
 #[cfg(test)]
 mod tests;
 

boa/src/object/mod.rs

@@ -29,6 +29,7 @@ mod gcobject;
 mod internal_methods;
 mod iter;
 
+use crate::builtins::object::for_in_iterator::ForInIterator;
 pub use gcobject::{GcObject, RecursionLimiter, Ref, RefMut};
 pub use iter::*;
 
@@ -84,6 +85,7 @@ pub enum ObjectData {
     RegExp(Box<RegExp>),
     BigInt(RcBigInt),
     Boolean(bool),
+    ForInIterator(ForInIterator),
     Function(Function),
     String(RcString),
     StringIterator(StringIterator),
@@ -104,6 +106,7 @@ impl Display for ObjectData {
             match self {
                 Self::Array => "Array",
                 Self::ArrayIterator(_) => "ArrayIterator",
+                Self::ForInIterator(_) => "ForInIterator",
                 Self::Function(_) => "Function",
                 Self::RegExp(_) => "RegExp",
                 Self::Map(_) => "Map",
@@ -311,6 +314,22 @@ impl Object {
         }
     }
 
+    #[inline]
+    pub fn as_for_in_iterator(&self) -> Option<&ForInIterator> {
+        match &self.data {
+            ObjectData::ForInIterator(iter) => Some(iter),
+            _ => None,
+        }
+    }
+
+    #[inline]
+    pub fn as_for_in_iterator_mut(&mut self) -> Option<&mut ForInIterator> {
+        match &mut self.data {
+            ObjectData::ForInIterator(iter) => Some(iter),
+            _ => None,
+        }
+    }
+
     /// Checks if it is a `Map` object.pub
     #[inline]
     pub fn is_map(&self) -> bool {

boa/src/syntax/ast/node/iteration/do_while_loop/mod.rs

@@ -42,6 +42,10 @@ impl DoWhileLoop {
         self.label.as_ref().map(Box::as_ref)
     }
 
+    pub fn set_label(&mut self, label: Box<str>) {
+        self.label = Some(label);
+    }
+
     /// Creates a `DoWhileLoop` AST node.
     pub fn new<B, C>(body: B, condition: C) -> Self
     where
@@ -68,50 +72,16 @@ impl DoWhileLoop {
 
 impl Executable for DoWhileLoop {
     fn run(&self, context: &mut Context) -> Result<Value> {
-        let mut result = self.body().run(context)?;
-        match context.executor().get_current_state() {
-            InterpreterState::Break(_label) => {
-                // TODO break to label.
-
-                // Loops 'consume' breaks.
-                context
-                    .executor()
-                    .set_current_state(InterpreterState::Executing);
-                return Ok(result);
-            }
-            InterpreterState::Continue(_label) => {
-                // TODO continue to label;
-                context
-                    .executor()
-                    .set_current_state(InterpreterState::Executing);
-                // after breaking out of the block, continue execution of the loop
-            }
-            InterpreterState::Return => {
-                return Ok(result);
-            }
-            InterpreterState::Executing => {
-                // Continue execution.
-            }
-        }
-
-        while self.cond().run(context)?.to_boolean() {
+        let mut result;
+        loop {
             result = self.body().run(context)?;
             match context.executor().get_current_state() {
-                InterpreterState::Break(_label) => {
-                    // TODO break to label.
-
-                    // Loops 'consume' breaks.
-                    context
-                        .executor()
-                        .set_current_state(InterpreterState::Executing);
+                InterpreterState::Break(label) => {
+                    handle_state_with_labels!(self, label, context, break);
                     break;
                 }
-                InterpreterState::Continue(_label) => {
-                    // TODO continue to label.
-                    context
-                        .executor()
-                        .set_current_state(InterpreterState::Executing);
-                    // after breaking out of the block, continue execution of the loop
+                InterpreterState::Continue(label) => {
+                    handle_state_with_labels!(self, label, context, continue);
                 }
                 InterpreterState::Return => {
                     return Ok(result);
@@ -120,6 +90,9 @@ impl Executable for DoWhileLoop {
                     // Continue execution.
                 }
             }
+            if !self.cond().run(context)?.to_boolean() {
+                break;
+            }
         }
         Ok(result)
     }