LibJS: Convert call_job_callback() to ThrowCompletionOr

Author: https://github.com/linusg
Commit: https://github.com/SerenityOS/serenity/commit/cd391aa8ef8
Pull-request: https://github.com/SerenityOS/serenity/pull/10913
Reviewed-by: https://github.com/IdanHo ✅

Userland/Libraries/LibJS/Runtime/JobCallback.h

@@ -6,8 +6,9 @@
 
 #pragma once
 
+#include <LibJS/Runtime/AbstractOperations.h>
+#include <LibJS/Runtime/Completion.h>
 #include <LibJS/Runtime/FunctionObject.h>
-#include <LibJS/Runtime/VM.h>
 
 namespace JS {
 
@@ -19,16 +20,19 @@ struct JobCallback {
 // 9.5.2 HostMakeJobCallback ( callback ), https://tc39.es/ecma262/#sec-hostmakejobcallback
 inline JobCallback make_job_callback(FunctionObject& callback)
 {
+    // 1. Return the JobCallback Record { [[Callback]]: callback, [[HostDefined]]: empty }.
     return { &callback };
 }
 
 // 9.5.3 HostCallJobCallback ( jobCallback, V, argumentsList ), https://tc39.es/ecma262/#sec-hostcalljobcallback
 template<typename... Args>
-[[nodiscard]] inline Value call_job_callback(VM& vm, JobCallback& job_callback, Value this_value, Args... args)
+inline ThrowCompletionOr<Value> call_job_callback(GlobalObject& global_object, JobCallback& job_callback, Value this_value, Args... args)
 {
+    // 1. Assert: IsCallable(jobCallback.[[Callback]]) is true.
     VERIFY(job_callback.callback);
-    auto& callback = *job_callback.callback;
-    return TRY_OR_DISCARD(vm.call(callback, this_value, args...));
+
+    // 2. Return ? Call(jobCallback.[[Callback]], V, argumentsList).
+    return call(global_object, job_callback.callback, this_value, args...);
 }
 
 }

Userland/Libraries/LibJS/Runtime/PromiseJobs.cpp

@@ -29,6 +29,7 @@ PromiseReactionJob::PromiseReactionJob(PromiseReaction& reaction, Value argument
 ThrowCompletionOr<Value> PromiseReactionJob::call()
 {
     auto& vm = this->vm();
+    auto& global_object = this->global_object();
 
     // a. Let promiseCapability be reaction.[[Capability]].
     auto& promise_capability = m_reaction.capability();
@@ -39,7 +40,7 @@ ThrowCompletionOr<Value> PromiseReactionJob::call()
     // c. Let handler be reaction.[[Handler]].
     auto handler = m_reaction.handler();
 
-    Value handler_result;
+    Completion handler_result;
 
     // d. If handler is empty, then
     if (!handler.has_value()) {
@@ -48,7 +49,7 @@ ThrowCompletionOr<Value> PromiseReactionJob::call()
         // i. If type is Fulfill, let handlerResult be NormalCompletion(argument).
         if (type == PromiseReaction::Type::Fulfill) {
             dbgln_if(PROMISE_DEBUG, "[PromiseReactionJob @ {}]: Reaction type is Type::Fulfill, setting handler result to {}", this, m_argument);
-            handler_result = m_argument;
+            handler_result = normal_completion(m_argument);
         }
         // ii. Else,
         else {
@@ -56,15 +57,14 @@ ThrowCompletionOr<Value> PromiseReactionJob::call()
             VERIFY(type == PromiseReaction::Type::Reject);
 
             // 2. Let handlerResult be ThrowCompletion(argument).
-            // NOTE: handler_result is set to exception value further below
             dbgln_if(PROMISE_DEBUG, "[PromiseReactionJob @ {}]: Reaction type is Type::Reject, throwing exception with argument {}", this, m_argument);
-            vm.throw_exception(global_object(), m_argument);
+            handler_result = throw_completion(m_argument);
         }
     }
     // e. Else, let handlerResult be HostCallJobCallback(handler, undefined, « argument »).
     else {
         dbgln_if(PROMISE_DEBUG, "[PromiseReactionJob @ {}]: Calling handler callback {} @ {} with argument {}", this, handler.value().callback->class_name(), handler.value().callback, m_argument);
-        handler_result = call_job_callback(vm, handler.value(), js_undefined(), m_argument);
+        handler_result = call_job_callback(global_object, handler.value(), js_undefined(), m_argument);
     }
 
     // f. If promiseCapability is undefined, then
@@ -82,22 +82,21 @@ ThrowCompletionOr<Value> PromiseReactionJob::call()
     // g. Assert: promiseCapability is a PromiseCapability Record.
 
     // h. If handlerResult is an abrupt completion, then
-    if (vm.exception()) {
-        handler_result = vm.exception()->value();
+    if (handler_result.is_abrupt()) {
         vm.clear_exception();
         vm.stop_unwind();
 
         // i. Let status be Call(promiseCapability.[[Reject]], undefined, « handlerResult.[[Value]] »).
         auto* reject_function = promise_capability.value().reject;
         dbgln_if(PROMISE_DEBUG, "[PromiseReactionJob @ {}]: Calling PromiseCapability's reject function @ {}", this, reject_function);
-        return vm.call(*reject_function, js_undefined(), handler_result);
+        return vm.call(*reject_function, js_undefined(), handler_result.value());
     }
     // i. Else,
     else {
         // i. Let status be Call(promiseCapability.[[Resolve]], undefined, « handlerResult.[[Value]] »).
         auto* resolve_function = promise_capability.value().resolve;
         dbgln_if(PROMISE_DEBUG, "[PromiseReactionJob @ {}]: Calling PromiseCapability's resolve function @ {}", this, resolve_function);
-        return vm.call(*resolve_function, js_undefined(), handler_result);
+        return vm.call(*resolve_function, js_undefined(), handler_result.value());
     }
 
     // j. Return Completion(status).
@@ -128,17 +127,18 @@ PromiseResolveThenableJob::PromiseResolveThenableJob(Promise& promise_to_resolve
 ThrowCompletionOr<Value> PromiseResolveThenableJob::call()
 {
     auto& vm = this->vm();
+    auto& global_object = this->global_object();
 
     // a. Let resolvingFunctions be CreateResolvingFunctions(promiseToResolve).
     auto [resolve_function, reject_function] = m_promise_to_resolve.create_resolving_functions();
 
     // b. Let thenCallResult be HostCallJobCallback(then, thenable, « resolvingFunctions.[[Resolve]], resolvingFunctions.[[Reject]] »).
     dbgln_if(PROMISE_DEBUG, "[PromiseResolveThenableJob @ {}]: Calling then job callback for thenable {}", this, &m_thenable);
-    auto then_call_result = call_job_callback(vm, m_then, m_thenable, &resolve_function, &reject_function);
+    auto then_call_result = call_job_callback(global_object, m_then, m_thenable, &resolve_function, &reject_function);
 
     // c. If thenCallResult is an abrupt completion, then
-    if (vm.exception()) {
-        auto error = vm.exception()->value();
+    if (then_call_result.is_error()) {
+        auto error = then_call_result.throw_completion().value();
         vm.clear_exception();
         vm.stop_unwind();
 
@@ -151,7 +151,7 @@ ThrowCompletionOr<Value> PromiseResolveThenableJob::call()
     }
 
     // d. Return Completion(thenCallResult).
-    dbgln_if(PROMISE_DEBUG, "[PromiseResolveThenableJob @ {}]: Returning then call result {}", this, then_call_result);
+    dbgln_if(PROMISE_DEBUG, "[PromiseResolveThenableJob @ {}]: Returning then call result {}", this, then_call_result.value());
     return then_call_result;
 }