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'use strict';
const {
NumberIsSafeInteger,
ReflectApply,
Symbol,
} = primordials;
const {
ERR_ASYNC_CALLBACK,
ERR_INVALID_ASYNC_ID
} = require('internal/errors').codes;
const { validateString } = require('internal/validators');
const internal_async_hooks = require('internal/async_hooks');
// Get functions
// For userland AsyncResources, make sure to emit a destroy event when the
// resource gets gced.
const { registerDestroyHook } = internal_async_hooks;
const {
executionAsyncId,
triggerAsyncId,
// Private API
hasAsyncIdStack,
getHookArrays,
enableHooks,
disableHooks,
// Internal Embedder API
newAsyncId,
getDefaultTriggerAsyncId,
emitInit,
emitBefore,
emitAfter,
emitDestroy,
initHooksExist,
} = internal_async_hooks;
// Get symbols
const {
async_id_symbol, trigger_async_id_symbol,
init_symbol, before_symbol, after_symbol, destroy_symbol,
promise_resolve_symbol
} = internal_async_hooks.symbols;
// Get constants
const {
kInit, kBefore, kAfter, kDestroy, kTotals, kPromiseResolve,
} = internal_async_hooks.constants;
// Listener API //
class AsyncHook {
constructor({ init, before, after, destroy, promiseResolve }) {
if (init !== undefined && typeof init !== 'function')
throw new ERR_ASYNC_CALLBACK('hook.init');
if (before !== undefined && typeof before !== 'function')
throw new ERR_ASYNC_CALLBACK('hook.before');
if (after !== undefined && typeof after !== 'function')
throw new ERR_ASYNC_CALLBACK('hook.after');
if (destroy !== undefined && typeof destroy !== 'function')
throw new ERR_ASYNC_CALLBACK('hook.destroy');
if (promiseResolve !== undefined && typeof promiseResolve !== 'function')
throw new ERR_ASYNC_CALLBACK('hook.promiseResolve');
this[init_symbol] = init;
this[before_symbol] = before;
this[after_symbol] = after;
this[destroy_symbol] = destroy;
this[promise_resolve_symbol] = promiseResolve;
}
enable() {
// The set of callbacks for a hook should be the same regardless of whether
// enable()/disable() are run during their execution. The following
// references are reassigned to the tmp arrays if a hook is currently being
// processed.
const [hooks_array, hook_fields] = getHookArrays();
// Each hook is only allowed to be added once.
if (hooks_array.includes(this))
return this;
const prev_kTotals = hook_fields[kTotals];
// createHook() has already enforced that the callbacks are all functions,
// so here simply increment the count of whether each callbacks exists or
// not.
hook_fields[kTotals] = hook_fields[kInit] += +!!this[init_symbol];
hook_fields[kTotals] += hook_fields[kBefore] += +!!this[before_symbol];
hook_fields[kTotals] += hook_fields[kAfter] += +!!this[after_symbol];
hook_fields[kTotals] += hook_fields[kDestroy] += +!!this[destroy_symbol];
hook_fields[kTotals] +=
hook_fields[kPromiseResolve] += +!!this[promise_resolve_symbol];
hooks_array.push(this);
if (prev_kTotals === 0 && hook_fields[kTotals] > 0) {
enableHooks();
}
return this;
}
disable() {
const [hooks_array, hook_fields] = getHookArrays();
const index = hooks_array.indexOf(this);
if (index === -1)
return this;
const prev_kTotals = hook_fields[kTotals];
hook_fields[kTotals] = hook_fields[kInit] -= +!!this[init_symbol];
hook_fields[kTotals] += hook_fields[kBefore] -= +!!this[before_symbol];
hook_fields[kTotals] += hook_fields[kAfter] -= +!!this[after_symbol];
hook_fields[kTotals] += hook_fields[kDestroy] -= +!!this[destroy_symbol];
hook_fields[kTotals] +=
hook_fields[kPromiseResolve] -= +!!this[promise_resolve_symbol];
hooks_array.splice(index, 1);
if (prev_kTotals > 0 && hook_fields[kTotals] === 0) {
disableHooks();
}
return this;
}
}
function createHook(fns) {
return new AsyncHook(fns);
}
// Embedder API //
const destroyedSymbol = Symbol('destroyed');
class AsyncResource {
constructor(type, opts = {}) {
validateString(type, 'type');
let triggerAsyncId = opts;
let requireManualDestroy = false;
if (typeof opts !== 'number') {
triggerAsyncId = opts.triggerAsyncId === undefined ?
getDefaultTriggerAsyncId() : opts.triggerAsyncId;
requireManualDestroy = !!opts.requireManualDestroy;
}
// Unlike emitInitScript, AsyncResource doesn't supports null as the
// triggerAsyncId.
if (!NumberIsSafeInteger(triggerAsyncId) || triggerAsyncId < -1) {
throw new ERR_INVALID_ASYNC_ID('triggerAsyncId', triggerAsyncId);
}
const asyncId = newAsyncId();
this[async_id_symbol] = asyncId;
this[trigger_async_id_symbol] = triggerAsyncId;
if (initHooksExist()) {
emitInit(asyncId, type, triggerAsyncId, this);
}
if (!requireManualDestroy) {
// This prop name (destroyed) has to be synchronized with C++
const destroyed = { destroyed: false };
this[destroyedSymbol] = destroyed;
registerDestroyHook(this, asyncId, destroyed);
}
}
runInAsyncScope(fn, thisArg, ...args) {
const asyncId = this[async_id_symbol];
emitBefore(asyncId, this[trigger_async_id_symbol]);
try {
if (thisArg === undefined)
return fn(...args);
return ReflectApply(fn, thisArg, args);
} finally {
if (hasAsyncIdStack())
emitAfter(asyncId);
}
}
emitDestroy() {
if (this[destroyedSymbol] !== undefined) {
this[destroyedSymbol].destroyed = true;
}
emitDestroy(this[async_id_symbol]);
return this;
}
asyncId() {
return this[async_id_symbol];
}
triggerAsyncId() {
return this[trigger_async_id_symbol];
}
}
// Placing all exports down here because the exported classes won't export
// otherwise.
module.exports = {
// Public API
createHook,
executionAsyncId,
triggerAsyncId,
// Embedder API
AsyncResource,
};
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