UNPKG

koffi

Version:

Fast and simple C FFI (foreign function interface) for Node.js

81 lines (55 loc) 2.59 kB
# EscapableHandleScope The `Napi::EscapableHandleScope` class is used to manage the lifetime of object handles which are created through the use of node-addon-api. These handles keep an object alive in the heap in order to ensure that the objects are not collected by the garbage collector while native code is using them. A handle may be created when any new node-addon-api Value or one of its subclasses is created or returned. The `Napi::EscapableHandleScope` is a special type of `Napi::HandleScope` which allows a single handle to be "promoted" to an outer scope. For more details refer to the section titled [Object lifetime management](object_lifetime_management.md). ## Methods ### Constructor Creates a new escapable handle scope. ```cpp Napi::EscapableHandleScope Napi::EscapableHandleScope::New(Napi::Env env); ``` - `[in] Env`: The environment in which to construct the `Napi::EscapableHandleScope` object. Returns a new `Napi::EscapableHandleScope` ### Constructor Creates a new escapable handle scope. ```cpp Napi::EscapableHandleScope Napi::EscapableHandleScope::New(napi_env env, napi_handle_scope scope); ``` - `[in] env`: `napi_env` in which the scope passed in was created. - `[in] scope`: pre-existing `napi_handle_scope`. Returns a new `Napi::EscapableHandleScope` instance which wraps the `napi_escapable_handle_scope` handle passed in. This can be used to mix usage of the C Node-API and node-addon-api. ```cpp operator Napi::EscapableHandleScope::napi_escapable_handle_scope() const ``` Returns the Node-API `napi_escapable_handle_scope` wrapped by the `Napi::EscapableHandleScope` object. This can be used to mix usage of the C Node-API and node-addon-api by allowing the class to be used be converted to a `napi_escapable_handle_scope`. ### Destructor ```cpp Napi::EscapableHandleScope::~EscapableHandleScope(); ``` Deletes the `Napi::EscapableHandleScope` instance and allows any objects/handles created in the scope to be collected by the garbage collector. There is no guarantee as to when the garbage collector will do this. ### Escape ```cpp napi::Value Napi::EscapableHandleScope::Escape(napi_value escapee); ``` - `[in] escapee`: `Napi::Value` or `napi_env` to promote to the outer scope Returns `Napi::Value` which can be used in the outer scope. This method can be called at most once on a given `Napi::EscapableHandleScope`. If it is called more than once an exception will be thrown. ### Env ```cpp Napi::Env Napi::EscapableHandleScope::Env() const; ``` Returns the `Napi::Env` associated with the `Napi::EscapableHandleScope`.