Line data    Source code

       1             : // Copyright 2018 the V8 project authors. All rights reserved.
       2             : // Use of this source code is governed by a BSD-style license that can be
       3             : // found in the LICENSE file.
       4             : 
       5             : #ifndef V8_OBJECTS_JS_PROMISE_H_
       6             : #define V8_OBJECTS_JS_PROMISE_H_
       7             : 
       8             : #include "src/objects/js-objects.h"
       9             : #include "src/objects/promise.h"
      10             : 
      11             : // Has to be the last include (doesn't have include guards):
      12             : #include "src/objects/object-macros.h"
      13             : 
      14             : namespace v8 {
      15             : namespace internal {
      16             : 
      17             : // Representation of promise objects in the specification. Our layout of
      18             : // JSPromise differs a bit from the layout in the specification, for example
      19             : // there's only a single list of PromiseReaction objects, instead of separate
      20             : // lists for fulfill and reject reactions. The PromiseReaction carries both
      21             : // callbacks from the start, and is eventually morphed into the proper kind of
      22             : // PromiseReactionJobTask when the JSPromise is settled.
      23             : //
      24             : // We also overlay the result and reactions fields on the JSPromise, since
      25             : // the reactions are only necessary for pending promises, whereas the result
      26             : // is only meaningful for settled promises.
      27             : class JSPromise : public JSObject {
      28             :  public:
      29             :   // [reactions_or_result]: Smi 0 terminated list of PromiseReaction objects
      30             :   // in case the JSPromise was not settled yet, otherwise the result.
      31             :   DECL_ACCESSORS(reactions_or_result, Object)
      32             : 
      33             :   // [result]: Checks that the promise is settled and returns the result.
      34             :   inline Object result() const;
      35             : 
      36             :   // [reactions]: Checks that the promise is pending and returns the reactions.
      37             :   inline Object reactions() const;
      38             : 
      39             :   DECL_INT_ACCESSORS(flags)
      40             : 
      41             :   // [has_handler]: Whether this promise has a reject handler or not.
      42             :   DECL_BOOLEAN_ACCESSORS(has_handler)
      43             : 
      44             :   // [handled_hint]: Whether this promise will be handled by a catch
      45             :   // block in an async function.
      46             :   DECL_BOOLEAN_ACCESSORS(handled_hint)
      47             : 
      48             :   int async_task_id() const;
      49             :   void set_async_task_id(int id);
      50             : 
      51             :   static const char* Status(Promise::PromiseState status);
      52             :   Promise::PromiseState status() const;
      53             :   void set_status(Promise::PromiseState status);
      54             : 
      55             :   // ES section #sec-fulfillpromise
      56             :   static Handle<Object> Fulfill(Handle<JSPromise> promise,
      57             :                                 Handle<Object> value);
      58             :   // ES section #sec-rejectpromise
      59             :   static Handle<Object> Reject(Handle<JSPromise> promise, Handle<Object> reason,
      60             :                                bool debug_event = true);
      61             :   // ES section #sec-promise-resolve-functions
      62             :   V8_WARN_UNUSED_RESULT static MaybeHandle<Object> Resolve(
      63             :       Handle<JSPromise> promise, Handle<Object> resolution);
      64             : 
      65             :   DECL_CAST(JSPromise)
      66             : 
      67             :   // Dispatched behavior.
      68             :   DECL_PRINTER(JSPromise)
      69             :   DECL_VERIFIER(JSPromise)
      70             : 
      71             : #define JS_PROMISE_FIELDS(V)               \
      72             :   V(kReactionsOrResultOffset, kTaggedSize) \
      73             :   V(kFlagsOffset, kTaggedSize)             \
      74             :   /* Header size. */                       \
      75             :   V(kSize, 0)
      76             : 
      77             :   DEFINE_FIELD_OFFSET_CONSTANTS(JSObject::kHeaderSize, JS_PROMISE_FIELDS)
      78             : #undef JS_PROMISE_FIELDS
      79             : 
      80             :   static const int kSizeWithEmbedderFields =
      81             :       kSize + v8::Promise::kEmbedderFieldCount * kEmbedderDataSlotSize;
      82             : 
      83             :   // Flags layout.
      84             :   // The first two bits store the v8::Promise::PromiseState.
      85             :   static const int kStatusBits = 2;
      86             :   static const int kHasHandlerBit = 2;
      87             :   static const int kHandledHintBit = 3;
      88             :   class AsyncTaskIdField : public BitField<int, kHandledHintBit + 1, 22> {};
      89             : 
      90             :   static const int kStatusShift = 0;
      91             :   static const int kStatusMask = 0x3;
      92             :   STATIC_ASSERT(v8::Promise::kPending == 0);
      93             :   STATIC_ASSERT(v8::Promise::kFulfilled == 1);
      94             :   STATIC_ASSERT(v8::Promise::kRejected == 2);
      95             : 
      96             :  private:
      97             :   // ES section #sec-triggerpromisereactions
      98             :   static Handle<Object> TriggerPromiseReactions(Isolate* isolate,
      99             :                                                 Handle<Object> reactions,
     100             :                                                 Handle<Object> argument,
     101             :                                                 PromiseReaction::Type type);
     102             : 
     103       28100 :   OBJECT_CONSTRUCTORS(JSPromise, JSObject);
     104             : };
     105             : 
     106             : }  // namespace internal
     107             : }  // namespace v8
     108             : 
     109             : #include "src/objects/object-macros-undef.h"
     110             : 
     111             : #endif  // V8_OBJECTS_JS_PROMISE_H_