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'use strict';
const internalUtil = require('internal/util');
const async_wrap = process.binding('async_wrap');
const errors = require('internal/errors');
/* async_hook_fields is a Uint32Array wrapping the uint32_t array of
* Environment::AsyncHooks::fields_[]. Each index tracks the number of active
* hooks for each type.
*
* async_id_fields is a Float64Array wrapping the double array of
* Environment::AsyncHooks::async_id_fields_[]. Each index contains the ids for
* the various asynchronous states of the application. These are:
* kExecutionAsyncId: The async_id assigned to the resource responsible for the
* current execution stack.
* kTriggerAsyncId: The trigger_async_id of the resource responsible for
* the current execution stack.
* kAsyncIdCounter: Incremental counter tracking the next assigned async_id.
* kInitTriggerAsyncId: Written immediately before a resource's constructor
* that sets the value of the init()'s triggerAsyncId. The order of
* retrieving the triggerAsyncId value is passing directly to the
* constructor -> value set in kInitTriggerAsyncId -> executionAsyncId of
* the current resource.
*/
const { async_hook_fields, async_id_fields } = async_wrap;
// Store the pair executionAsyncId and triggerAsyncId in a std::stack on
// Environment::AsyncHooks::ids_stack_ tracks the resource responsible for the
// current execution stack. This is unwound as each resource exits. In the case
// of a fatal exception this stack is emptied after calling each hook's after()
// callback.
const { pushAsyncIds, popAsyncIds } = async_wrap;
// For performance reasons, only track Proimses when a hook is enabled.
const { enablePromiseHook, disablePromiseHook } = async_wrap;
// Properties in active_hooks are used to keep track of the set of hooks being
// executed in case another hook is enabled/disabled. The new set of hooks is
// then restored once the active set of hooks is finished executing.
const active_hooks = {
// Array of all AsyncHooks that will be iterated whenever an async event
// fires. Using var instead of (preferably const) in order to assign
// active_hooks.tmp_array if a hook is enabled/disabled during hook
// execution.
array: [],
// Use a counter to track nested calls of async hook callbacks and make sure
// the active_hooks.array isn't altered mid execution.
call_depth: 0,
// Use to temporarily store and updated active_hooks.array if the user
// enables or disables a hook while hooks are being processed. If a hook is
// enabled() or disabled() during hook execution then the current set of
// active hooks is duplicated and set equal to active_hooks.tmp_array. Any
// subsequent changes are on the duplicated array. When all hooks have
// completed executing active_hooks.tmp_array is assigned to
// active_hooks.array.
tmp_array: null,
// Keep track of the field counts held in active_hooks.tmp_array. Because the
// async_hook_fields can't be reassigned, store each uint32 in an array that
// is written back to async_hook_fields when active_hooks.array is restored.
tmp_fields: null
};
// Each constant tracks how many callbacks there are for any given step of
// async execution. These are tracked so if the user didn't include callbacks
// for a given step, that step can bail out early.
const { kInit, kBefore, kAfter, kDestroy, kTotals, kPromiseResolve,
kCheck, kExecutionAsyncId, kTriggerAsyncId, kAsyncIdCounter,
kInitTriggerAsyncId } = async_wrap.constants;
// Symbols used to store the respective ids on both AsyncResource instances and
// internal resources. They will also be assigned to arbitrary objects passed
// in by the user that take place of internally constructed objects.
const { async_id_symbol, trigger_async_id_symbol } = async_wrap;
// Used in AsyncHook and AsyncResource.
const init_symbol = Symbol('init');
const before_symbol = Symbol('before');
const after_symbol = Symbol('after');
const destroy_symbol = Symbol('destroy');
const promise_resolve_symbol = Symbol('promiseResolve');
const emitBeforeNative = emitHookFactory(before_symbol, 'emitBeforeNative');
const emitAfterNative = emitHookFactory(after_symbol, 'emitAfterNative');
const emitDestroyNative = emitHookFactory(destroy_symbol, 'emitDestroyNative');
const emitPromiseResolveNative =
emitHookFactory(promise_resolve_symbol, 'emitPromiseResolveNative');
// TODO(refack): move to node-config.cc
const abort_regex = /^--abort[_-]on[_-]uncaught[_-]exception$/;
// Setup the callbacks that node::AsyncWrap will call when there are hooks to
// process. They use the same functions as the JS embedder API. These callbacks
// are setup immediately to prevent async_wrap.setupHooks() from being hijacked
// and the cost of doing so is negligible.
async_wrap.setupHooks({ init: emitInitNative,
before: emitBeforeNative,
after: emitAfterNative,
destroy: emitDestroyNative,
promise_resolve: emitPromiseResolveNative });
// Used to fatally abort the process if a callback throws.
function fatalError(e) {
if (typeof e.stack === 'string') {
process._rawDebug(e.stack);
} else {
const o = { message: e };
Error.captureStackTrace(o, fatalError);
process._rawDebug(o.stack);
}
if (process.execArgv.some((e) => abort_regex.test(e))) {
process.abort();
}
process.exit(1);
}
// Public API //
class AsyncHook {
constructor({ init, before, after, destroy, promiseResolve }) {
if (init !== undefined && typeof init !== 'function')
throw new errors.TypeError('ERR_ASYNC_CALLBACK', 'init');
if (before !== undefined && typeof before !== 'function')
throw new errors.TypeError('ERR_ASYNC_CALLBACK', 'before');
if (after !== undefined && typeof after !== 'function')
throw new errors.TypeError('ERR_ASYNC_CALLBACK', 'before');
if (destroy !== undefined && typeof destroy !== 'function')
throw new errors.TypeError('ERR_ASYNC_CALLBACK', 'before');
if (promiseResolve !== undefined && typeof promiseResolve !== 'function')
throw new errors.TypeError('ERR_ASYNC_CALLBACK', '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];
hook_fields[kTotals] = 0;
// 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) {
enablePromiseHook();
hook_fields[kCheck] += 1;
}
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] = 0;
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) {
disablePromiseHook();
hook_fields[kCheck] -= 1;
}
return this;
}
}
function getHookArrays() {
if (active_hooks.call_depth === 0)
return [active_hooks.array, async_hook_fields];
// If this hook is being enabled while in the middle of processing the array
// of currently active hooks then duplicate the current set of active hooks
// and store this there. This shouldn't fire until the next time hooks are
// processed.
if (active_hooks.tmp_array === null)
storeActiveHooks();
return [active_hooks.tmp_array, active_hooks.tmp_fields];
}
function storeActiveHooks() {
active_hooks.tmp_array = active_hooks.array.slice();
// Don't want to make the assumption that kInit to kDestroy are indexes 0 to
// 4. So do this the long way.
active_hooks.tmp_fields = [];
active_hooks.tmp_fields[kInit] = async_hook_fields[kInit];
active_hooks.tmp_fields[kBefore] = async_hook_fields[kBefore];
active_hooks.tmp_fields[kAfter] = async_hook_fields[kAfter];
active_hooks.tmp_fields[kDestroy] = async_hook_fields[kDestroy];
active_hooks.tmp_fields[kPromiseResolve] = async_hook_fields[kPromiseResolve];
}
// Then restore the correct hooks array in case any hooks were added/removed
// during hook callback execution.
function restoreActiveHooks() {
active_hooks.array = active_hooks.tmp_array;
async_hook_fields[kInit] = active_hooks.tmp_fields[kInit];
async_hook_fields[kBefore] = active_hooks.tmp_fields[kBefore];
async_hook_fields[kAfter] = active_hooks.tmp_fields[kAfter];
async_hook_fields[kDestroy] = active_hooks.tmp_fields[kDestroy];
async_hook_fields[kPromiseResolve] = active_hooks.tmp_fields[kPromiseResolve];
active_hooks.tmp_array = null;
active_hooks.tmp_fields = null;
}
function createHook(fns) {
return new AsyncHook(fns);
}
function executionAsyncId() {
return async_id_fields[kExecutionAsyncId];
}
function triggerAsyncId() {
return async_id_fields[kTriggerAsyncId];
}
function validateAsyncId(asyncId, type) {
// Skip validation when async_hooks is disabled
if (async_hook_fields[kCheck] <= 0) return;
if (!Number.isSafeInteger(asyncId) || asyncId < -1) {
fatalError(new errors.RangeError('ERR_INVALID_ASYNC_ID', type, asyncId));
}
}
// Embedder API //
class AsyncResource {
constructor(type, triggerAsyncId = initTriggerId()) {
if (typeof type !== 'string')
throw new errors.TypeError('ERR_INVALID_ARG_TYPE', 'type', 'string');
// Unlike emitInitScript, AsyncResource doesn't supports null as the
// triggerAsyncId.
if (!Number.isSafeInteger(triggerAsyncId) || triggerAsyncId < -1) {
throw new errors.RangeError('ERR_INVALID_ASYNC_ID',
'triggerAsyncId',
triggerAsyncId);
}
this[async_id_symbol] = ++async_id_fields[kAsyncIdCounter];
this[trigger_async_id_symbol] = triggerAsyncId;
emitInitScript(
this[async_id_symbol], type, this[trigger_async_id_symbol], this
);
}
emitBefore() {
emitBeforeScript(this[async_id_symbol], this[trigger_async_id_symbol]);
return this;
}
emitAfter() {
emitAfterScript(this[async_id_symbol]);
return this;
}
emitDestroy() {
emitDestroyScript(this[async_id_symbol]);
return this;
}
asyncId() {
return this[async_id_symbol];
}
triggerAsyncId() {
return this[trigger_async_id_symbol];
}
}
// triggerId was renamed to triggerAsyncId. This was in 8.2.0 during the
// experimental stage so the alias can be removed at any time, we are just
// being nice :)
Object.defineProperty(AsyncResource.prototype, 'triggerId', {
get: internalUtil.deprecate(function() {
return AsyncResource.prototype.triggerAsyncId;
}, 'AsyncResource.triggerId is deprecated. ' +
'Use AsyncResource.triggerAsyncId instead.', 'DEP0072')
});
function runInAsyncIdScope(asyncId, cb) {
// Store the async id now to make sure the stack is still good when the ids
// are popped off the stack.
const prevId = executionAsyncId();
pushAsyncIds(asyncId, prevId);
try {
cb();
} finally {
popAsyncIds(asyncId);
}
}
// Sensitive Embedder API //
// Increment the internal id counter and return the value. Important that the
// counter increment first. Since it's done the same way in
// Environment::new_async_uid()
function newUid() {
return ++async_id_fields[kAsyncIdCounter];
}
// Return the triggerAsyncId meant for the constructor calling it. It's up to
// the user to safeguard this call and make sure it's zero'd out when the
// constructor is complete.
function initTriggerId() {
var triggerAsyncId = async_id_fields[kInitTriggerAsyncId];
// Reset value after it's been called so the next constructor doesn't
// inherit it by accident.
async_id_fields[kInitTriggerAsyncId] = 0;
if (triggerAsyncId <= 0)
triggerAsyncId = async_id_fields[kExecutionAsyncId];
return triggerAsyncId;
}
function setInitTriggerId(triggerAsyncId) {
// CHECK(Number.isSafeInteger(triggerAsyncId))
// CHECK(triggerAsyncId > 0)
async_id_fields[kInitTriggerAsyncId] = triggerAsyncId;
}
function emitInitScript(asyncId, type, triggerAsyncId, resource) {
validateAsyncId(asyncId, 'asyncId');
if (triggerAsyncId !== null)
validateAsyncId(triggerAsyncId, 'triggerAsyncId');
if (async_hook_fields[kCheck] > 0 &&
(typeof type !== 'string' || type.length <= 0)) {
throw new errors.TypeError('ERR_ASYNC_TYPE', type);
}
// Short circuit all checks for the common case. Which is that no hooks have
// been set. Do this to remove performance impact for embedders (and core).
if (async_hook_fields[kInit] === 0)
return;
// This can run after the early return check b/c running this function
// manually means that the embedder must have used initTriggerId().
if (triggerAsyncId === null) {
triggerAsyncId = initTriggerId();
} else {
// If a triggerAsyncId was passed, any kInitTriggerAsyncId still must be
// null'd.
async_id_fields[kInitTriggerAsyncId] = 0;
}
emitInitNative(asyncId, type, triggerAsyncId, resource);
}
function emitHookFactory(symbol, name) {
// Called from native. The asyncId stack handling is taken care of there
// before this is called.
// eslint-disable-next-line func-style
const fn = function(asyncId) {
active_hooks.call_depth += 1;
// Use a single try/catch for all hook to avoid setting up one per
// iteration.
try {
for (var i = 0; i < active_hooks.array.length; i++) {
if (typeof active_hooks.array[i][symbol] === 'function') {
active_hooks.array[i][symbol](asyncId);
}
}
} catch (e) {
fatalError(e);
} finally {
active_hooks.call_depth -= 1;
}
// Hooks can only be restored if there have been no recursive hook calls.
// Also the active hooks do not need to be restored if enable()/disable()
// weren't called during hook execution, in which case
// active_hooks.tmp_array will be null.
if (active_hooks.call_depth === 0 && active_hooks.tmp_array !== null) {
restoreActiveHooks();
}
};
// Set the name property of the anonymous function as it looks good in the
// stack trace.
Object.defineProperty(fn, 'name', {
value: name
});
return fn;
}
function emitBeforeScript(asyncId, triggerAsyncId) {
// Validate the ids. An id of -1 means it was never set and is visible on the
// call graph. An id < -1 should never happen in any circumstance. Throw
// on user calls because async state should still be recoverable.
validateAsyncId(asyncId, 'asyncId');
validateAsyncId(triggerAsyncId, 'triggerAsyncId');
pushAsyncIds(asyncId, triggerAsyncId);
if (async_hook_fields[kBefore] > 0)
emitBeforeNative(asyncId);
}
function emitAfterScript(asyncId) {
validateAsyncId(asyncId, 'asyncId');
if (async_hook_fields[kAfter] > 0)
emitAfterNative(asyncId);
popAsyncIds(asyncId);
}
function emitDestroyScript(asyncId) {
validateAsyncId(asyncId, 'asyncId');
// Return early if there are no destroy callbacks, or invalid asyncId.
if (async_hook_fields[kDestroy] === 0 || asyncId <= 0)
return;
async_wrap.queueDestroyAsyncId(asyncId);
}
// Used by C++ to call all init() callbacks. Because some state can be setup
// from C++ there's no need to perform all the same operations as in
// emitInitScript.
function emitInitNative(asyncId, type, triggerAsyncId, resource) {
active_hooks.call_depth += 1;
// Use a single try/catch for all hook to avoid setting up one per iteration.
try {
for (var i = 0; i < active_hooks.array.length; i++) {
if (typeof active_hooks.array[i][init_symbol] === 'function') {
active_hooks.array[i][init_symbol](
asyncId, type, triggerAsyncId,
resource
);
}
}
} catch (e) {
fatalError(e);
} finally {
active_hooks.call_depth -= 1;
}
// Hooks can only be restored if there have been no recursive hook calls.
// Also the active hooks do not need to be restored if enable()/disable()
// weren't called during hook execution, in which case active_hooks.tmp_array
// will be null.
if (active_hooks.call_depth === 0 && active_hooks.tmp_array !== null) {
restoreActiveHooks();
}
}
// Placing all exports down here because the exported classes won't export
// otherwise.
module.exports = {
// Public API
createHook,
executionAsyncId,
triggerAsyncId,
// Embedder API
AsyncResource,
runInAsyncIdScope,
// Sensitive Embedder API
newUid,
initTriggerId,
setInitTriggerId,
emitInit: emitInitScript,
emitBefore: emitBeforeScript,
emitAfter: emitAfterScript,
emitDestroy: emitDestroyScript,
};
// currentId was renamed to executionAsyncId. This was in 8.2.0 during the
// experimental stage so the alias can be removed at any time, we are just
// being nice :)
Object.defineProperty(module.exports, 'currentId', {
get: internalUtil.deprecate(function() {
return executionAsyncId;
}, 'async_hooks.currentId is deprecated. ' +
'Use async_hooks.executionAsyncId instead.', 'DEP0070')
});
// triggerId was renamed to triggerAsyncId. This was in 8.2.0 during the
// experimental stage so the alias can be removed at any time, we are just
// being nice :)
Object.defineProperty(module.exports, 'triggerId', {
get: internalUtil.deprecate(function() {
return triggerAsyncId;
}, 'async_hooks.triggerId is deprecated. ' +
'Use async_hooks.triggerAsyncId instead.', 'DEP0071')
});
|