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	 9d0d3affd4
			
		
	
	
		9d0d3affd4
		
	
	
	
	
		
			
			This includes:
- Parsing proper LabelledStatements with try_parse_labelled_statement()
- Removing LabelableStatement
- Implementing the LoopEvaluation semantics via loop_evaluation() in
  each IterationStatement subclass; and IterationStatement evaluation
  via {For,ForIn,ForOf,ForAwaitOf,While,DoWhile}Statement::execute()
- Updating ReturnStatement, BreakStatement and ContinueStatement to
  return the appropriate completion types
- Basically reimplementing TryStatement and SwitchStatement according to
  the spec, using completions
- Honoring result completion types in AsyncBlockStart and
  OrdinaryCallEvaluateBody
- Removing any uses of the VM unwind mechanism - most importantly,
  VM::throw_exception() now exclusively sets an exception and no longer
  triggers any unwinding mechanism.
  However, we already did a good job updating all of LibWeb and userland
  applications to not use it, and the few remaining uses elsewhere don't
  rely on unwinding AFAICT.
		
	
			
		
			
				
	
	
		
			73 lines
		
	
	
	
		
			3.7 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			73 lines
		
	
	
	
		
			3.7 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2021, Linus Groh <linusg@serenityos.org>
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|  *
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|  * SPDX-License-Identifier: BSD-2-Clause
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|  */
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| 
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| #pragma once
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| 
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| #include <LibJS/Runtime/GlobalObject.h>
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| #include <LibJS/Runtime/JobCallback.h>
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| #include <LibJS/Runtime/VM.h>
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| 
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| namespace JS {
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| 
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| // 27.2.1.1 PromiseCapability Records, https://tc39.es/ecma262/#sec-promisecapability-records
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| struct PromiseCapability {
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|     Object* promise { nullptr };
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|     FunctionObject* resolve { nullptr };
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|     FunctionObject* reject { nullptr };
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| };
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| 
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| // 27.2.1.1.1 IfAbruptRejectPromise ( value, capability ), https://tc39.es/ecma262/#sec-ifabruptrejectpromise
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| #define TRY_OR_REJECT(vm, capability, expression)                                                                       \
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|     ({                                                                                                                  \
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|         auto _temporary_try_or_reject_result = (expression);                                                            \
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|         /* 1. If value is an abrupt completion, then */                                                                 \
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|         if (_temporary_try_or_reject_result.is_error()) {                                                               \
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|             vm.clear_exception();                                                                                       \
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|                                                                                                                         \
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|             /* a. Perform ? Call(capability.[[Reject]], undefined, « value.[[Value]] »). */                           \
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|             TRY(vm.call(*capability.reject, js_undefined(), *_temporary_try_or_reject_result.release_error().value())); \
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|                                                                                                                         \
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|             /* b. Return capability.[[Promise]]. */                                                                     \
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|             return capability.promise;                                                                                  \
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|         }                                                                                                               \
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|                                                                                                                         \
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|         /* 2. Else if value is a Completion Record, set value to value.[[Value]]. */                                    \
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|         _temporary_try_or_reject_result.release_value();                                                                \
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|     })
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| 
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| // 27.2.1.5 NewPromiseCapability ( C ), https://tc39.es/ecma262/#sec-newpromisecapability
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| ThrowCompletionOr<PromiseCapability> new_promise_capability(GlobalObject& global_object, Value constructor);
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| 
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| // 27.2.1.2 PromiseReaction Records, https://tc39.es/ecma262/#sec-promisereaction-records
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| class PromiseReaction final : public Cell {
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| public:
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|     enum class Type {
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|         Fulfill,
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|         Reject,
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|     };
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| 
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|     static PromiseReaction* create(VM& vm, Type type, Optional<PromiseCapability> capability, Optional<JobCallback> handler)
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|     {
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|         return vm.heap().allocate_without_global_object<PromiseReaction>(type, capability, handler);
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|     }
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| 
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|     PromiseReaction(Type type, Optional<PromiseCapability> capability, Optional<JobCallback> handler);
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|     virtual ~PromiseReaction() = default;
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| 
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|     Type type() const { return m_type; }
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|     const Optional<PromiseCapability>& capability() const { return m_capability; }
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|     const Optional<JobCallback>& handler() const { return m_handler; }
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| 
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| private:
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|     virtual const char* class_name() const override { return "PromiseReaction"; }
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|     virtual void visit_edges(Visitor&) override;
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| 
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|     Type m_type;
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|     Optional<PromiseCapability> m_capability;
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|     Optional<JobCallback> m_handler;
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| };
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| 
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| }
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