From 7efb8f7619100973877c660d0ee527ea3d92de8d Mon Sep 17 00:00:00 2001 From: Gabriel Schulhof Date: Thu, 24 Aug 2017 13:33:26 +0300 Subject: n-api: implement promise Promise is implemented as a pair of objects. `napi_create_promise()` returns both a JavaScript promise and a newly allocated "deferred" in its out-params. The deferred is linked to the promise such that the deferred can be passed to `napi_resolve_deferred()` or `napi_reject_deferred()` to reject/resolve the promise. `napi_is_promise()` can be used to check if a `napi_value` is a native promise - that is, a promise created by the underlying engine, rather than a pure JS implementation of a promise. PR-URL: https://github.com/nodejs/node/pull/14365 Fixes: https://github.com/nodejs/abi-stable-node/issues/242 Reviewed-By: Anna Henningsen Reviewed-By: James M Snell Reviewed-By: Benjamin Gruenbaum Reviewed-By: Timothy Gu --- src/node_api.cc | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++ src/node_api.h | 14 ++++++++++ src/node_api_types.h | 1 + 3 files changed, 93 insertions(+) (limited to 'src') diff --git a/src/node_api.cc b/src/node_api.cc index bec98e07ce..7a2b5bc48e 100644 --- a/src/node_api.cc +++ b/src/node_api.cc @@ -218,6 +218,14 @@ V8EscapableHandleScopeFromJsEscapableHandleScope( static_assert(sizeof(v8::Local) == sizeof(napi_value), "Cannot convert between v8::Local and napi_value"); +napi_deferred JsDeferredFromV8Persistent(v8::Persistent* local) { + return reinterpret_cast(local); +} + +v8::Persistent* V8PersistentFromJsDeferred(napi_deferred local) { + return reinterpret_cast*>(local); +} + napi_value JsValueFromV8LocalValue(v8::Local local) { return reinterpret_cast(*local); } @@ -774,6 +782,33 @@ napi_status Unwrap(napi_env env, return napi_ok; } +napi_status ConcludeDeferred(napi_env env, + napi_deferred deferred, + napi_value result, + bool is_resolved) { + NAPI_PREAMBLE(env); + CHECK_ARG(env, result); + + v8::Local context = env->isolate->GetCurrentContext(); + v8::Persistent* deferred_ref = + V8PersistentFromJsDeferred(deferred); + v8::Local v8_deferred = + v8::Local::New(env->isolate, *deferred_ref); + + auto v8_resolver = v8::Local::Cast(v8_deferred); + + v8::Maybe success = is_resolved ? + v8_resolver->Resolve(context, v8impl::V8LocalValueFromJsValue(result)) : + v8_resolver->Reject(context, v8impl::V8LocalValueFromJsValue(result)); + + deferred_ref->Reset(); + delete deferred_ref; + + RETURN_STATUS_IF_FALSE(env, success.FromMaybe(false), napi_generic_failure); + + return GET_RETURN_STATUS(env); +} + } // end of namespace v8impl // Intercepts the Node-V8 module registration callback. Converts parameters @@ -3332,3 +3367,46 @@ napi_status napi_cancel_async_work(napi_env env, napi_async_work work) { return napi_clear_last_error(env); } + +NAPI_EXTERN napi_status napi_create_promise(napi_env env, + napi_deferred* deferred, + napi_value* promise) { + NAPI_PREAMBLE(env); + CHECK_ARG(env, deferred); + CHECK_ARG(env, promise); + + auto maybe = v8::Promise::Resolver::New(env->isolate->GetCurrentContext()); + CHECK_MAYBE_EMPTY(env, maybe, napi_generic_failure); + + auto v8_resolver = maybe.ToLocalChecked(); + auto v8_deferred = new v8::Persistent(); + v8_deferred->Reset(env->isolate, v8_resolver); + + *deferred = v8impl::JsDeferredFromV8Persistent(v8_deferred); + *promise = v8impl::JsValueFromV8LocalValue(v8_resolver->GetPromise()); + return GET_RETURN_STATUS(env); +} + +NAPI_EXTERN napi_status napi_resolve_deferred(napi_env env, + napi_deferred deferred, + napi_value resolution) { + return v8impl::ConcludeDeferred(env, deferred, resolution, true); +} + +NAPI_EXTERN napi_status napi_reject_deferred(napi_env env, + napi_deferred deferred, + napi_value resolution) { + return v8impl::ConcludeDeferred(env, deferred, resolution, false); +} + +NAPI_EXTERN napi_status napi_is_promise(napi_env env, + napi_value promise, + bool* is_promise) { + CHECK_ENV(env); + CHECK_ARG(env, promise); + CHECK_ARG(env, is_promise); + + *is_promise = v8impl::V8LocalValueFromJsValue(promise)->IsPromise(); + + return napi_clear_last_error(env); +} diff --git a/src/node_api.h b/src/node_api.h index e52e2016d7..6a4b294187 100644 --- a/src/node_api.h +++ b/src/node_api.h @@ -543,6 +543,20 @@ NAPI_EXTERN napi_status napi_get_node_version(napi_env env, const napi_node_version** version); +// Promises +NAPI_EXTERN napi_status napi_create_promise(napi_env env, + napi_deferred* deferred, + napi_value* promise); +NAPI_EXTERN napi_status napi_resolve_deferred(napi_env env, + napi_deferred deferred, + napi_value resolution); +NAPI_EXTERN napi_status napi_reject_deferred(napi_env env, + napi_deferred deferred, + napi_value rejection); +NAPI_EXTERN napi_status napi_is_promise(napi_env env, + napi_value promise, + bool* is_promise); + EXTERN_C_END #endif // SRC_NODE_API_H_ diff --git a/src/node_api_types.h b/src/node_api_types.h index 0bdc377c8f..ac8482bf9d 100644 --- a/src/node_api_types.h +++ b/src/node_api_types.h @@ -17,6 +17,7 @@ typedef struct napi_handle_scope__ *napi_handle_scope; typedef struct napi_escapable_handle_scope__ *napi_escapable_handle_scope; typedef struct napi_callback_info__ *napi_callback_info; typedef struct napi_async_work__ *napi_async_work; +typedef struct napi_deferred__ *napi_deferred; typedef enum { napi_default = 0, -- cgit v1.2.3