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/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2022, Luke Wilde <lukew@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/FlyString.h>
#include <AK/HashMap.h>
#include <AK/String.h>
#include <AK/Weakable.h>
#include <LibJS/AST.h>
#include <LibJS/Forward.h>
#include <LibJS/Heap/DeferGC.h>
#include <LibJS/Heap/Heap.h>
#include <LibJS/Heap/MarkedVector.h>
#include <LibJS/Runtime/Completion.h>
#include <LibJS/Runtime/DeclarativeEnvironment.h>
#include <LibJS/Runtime/ErrorTypes.h>
#include <LibJS/Runtime/GlobalEnvironment.h>
#include <LibJS/Runtime/GlobalObject.h>
#include <LibJS/Runtime/Realm.h>
#include <LibJS/Runtime/VM.h>
#include <LibJS/Runtime/Value.h>
#include <LibJS/Script.h>
#include <LibJS/SourceTextModule.h>
namespace JS {
struct ExecutingASTNodeChain {
ExecutingASTNodeChain* previous { nullptr };
ASTNode const& node;
};
class Interpreter : public Weakable<Interpreter> {
public:
// 9.6 InitializeHostDefinedRealm ( ), https://tc39.es/ecma262/#sec-initializehostdefinedrealm
template<typename GlobalObjectType, typename GlobalThisObjectType, typename... Args>
static NonnullOwnPtr<Interpreter> create(VM& vm, Args&&... args) requires(IsBaseOf<GlobalObject, GlobalObjectType>&& IsBaseOf<Object, GlobalThisObjectType>)
{
DeferGC defer_gc(vm.heap());
auto interpreter = adopt_own(*new Interpreter(vm));
VM::InterpreterExecutionScope scope(*interpreter);
// 1. Let realm be CreateRealm().
auto* realm = Realm::create(vm);
// 2. Let newContext be a new execution context.
auto& new_context = interpreter->m_global_execution_context;
// 3. Set the Function of newContext to null.
// NOTE: This was done during execution context construction.
// 4. Set the Realm of newContext to realm.
new_context.realm = realm;
// 5. Set the ScriptOrModule of newContext to null.
// NOTE: This was done during execution context construction.
// 6. Push newContext onto the execution context stack; newContext is now the running execution context.
vm.push_execution_context(new_context);
// 7. If the host requires use of an exotic object to serve as realm's global object, let global be such an object created in a host-defined manner.
// Otherwise, let global be undefined, indicating that an ordinary object should be created as the global object.
auto* global_object = static_cast<GlobalObject*>(interpreter->heap().allocate_without_global_object<GlobalObjectType>(forward<Args>(args)...));
// 8. If the host requires that the this binding in realm's global scope return an object other than the global object, let thisValue be such an object created
// in a host-defined manner. Otherwise, let thisValue be undefined, indicating that realm's global this binding should be the global object.
Object* this_value;
if constexpr (IsSame<GlobalObjectType, GlobalThisObjectType>) {
this_value = global_object;
} else {
// FIXME: Should we pass args in here? Let's er on the side of caution and say yes.
this_value = static_cast<Object*>(interpreter->heap().allocate_without_global_object<GlobalThisObjectType>(forward<Args>(args)...));
}
// 9. Perform SetRealmGlobalObject(realm, global, thisValue).
realm->set_global_object(*global_object, this_value);
// NOTE: These are not in the spec.
static FlyString global_execution_context_name = "(global execution context)";
interpreter->m_global_execution_context.function_name = global_execution_context_name;
interpreter->m_global_object = make_handle(global_object);
interpreter->m_realm = make_handle(realm);
// 10. Let globalObj be ? SetDefaultGlobalBindings(realm).
// 11. Create any host-defined global object properties on globalObj.
static_cast<GlobalObjectType*>(global_object)->initialize_global_object();
// 12. Return unused.
return interpreter;
}
template<typename GlobalObjectType, typename... Args>
static NonnullOwnPtr<Interpreter> create(VM& vm, Args&&... args) requires IsBaseOf<GlobalObject, GlobalObjectType>
{
// NOTE: This function is here to facilitate step 8 of InitializeHostDefinedRealm. (Callers don't have to specify the same type twice if not necessary)
return create<GlobalObjectType, GlobalObjectType>(vm, args...);
}
static NonnullOwnPtr<Interpreter> create_with_existing_realm(Realm&);
~Interpreter() = default;
ThrowCompletionOr<Value> run(Script&);
ThrowCompletionOr<Value> run(SourceTextModule&);
GlobalObject& global_object();
GlobalObject const& global_object() const;
Realm& realm();
Realm const& realm() const;
ALWAYS_INLINE VM& vm() { return *m_vm; }
ALWAYS_INLINE const VM& vm() const { return *m_vm; }
ALWAYS_INLINE Heap& heap() { return vm().heap(); }
Environment* lexical_environment() { return vm().lexical_environment(); }
void push_ast_node(ExecutingASTNodeChain& chain_node)
{
chain_node.previous = m_ast_node_chain;
m_ast_node_chain = &chain_node;
}
void pop_ast_node()
{
VERIFY(m_ast_node_chain);
m_ast_node_chain = m_ast_node_chain->previous;
}
ASTNode const* current_node() const { return m_ast_node_chain ? &m_ast_node_chain->node : nullptr; }
private:
explicit Interpreter(VM&);
ExecutingASTNodeChain* m_ast_node_chain { nullptr };
NonnullRefPtr<VM> m_vm;
Handle<GlobalObject> m_global_object;
Handle<Realm> m_realm;
// This is here to keep the global execution context alive for the entire lifespan of the Interpreter.
ExecutionContext m_global_execution_context;
};
}
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