CasperSecurity
/*
MIT License http://www.opensource.org/licenses/mit-license.php
Author Tobias Koppers @sokra
*/
"use strict";
const nextTick = require("process").nextTick;
/** @typedef {import("./Resolver").FileSystem} FileSystem */
/** @typedef {import("./Resolver").SyncFileSystem} SyncFileSystem */
const dirname = path => {
let idx = path.length - 1;
while (idx >= 0) {
const c = path.charCodeAt(idx);
// slash or backslash
if (c === 47 || c === 92) break;
idx--;
}
if (idx < 0) return "";
return path.slice(0, idx);
};
const runCallbacks = (callbacks, err, result) => {
if (callbacks.length === 1) {
callbacks[0](err, result);
callbacks.length = 0;
return;
}
let error;
for (const callback of callbacks) {
try {
callback(err, result);
} catch (e) {
if (!error) error = e;
}
}
callbacks.length = 0;
if (error) throw error;
};
class OperationMergerBackend {
/**
* @param {any} provider async method
* @param {any} syncProvider sync method
* @param {any} providerContext call context for the provider methods
*/
constructor(provider, syncProvider, providerContext) {
this._provider = provider;
this._syncProvider = syncProvider;
this._providerContext = providerContext;
this._activeAsyncOperations = new Map();
this.provide = this._provider
? (path, options, callback) => {
if (typeof options === "function") {
callback = options;
options = undefined;
}
if (options) {
return this._provider.call(
this._providerContext,
path,
options,
callback
);
}
if (typeof path !== "string") {
callback(new TypeError("path must be a string"));
return;
}
let callbacks = this._activeAsyncOperations.get(path);
if (callbacks) {
callbacks.push(callback);
return;
}
this._activeAsyncOperations.set(path, (callbacks = [callback]));
provider(path, (err, result) => {
this._activeAsyncOperations.delete(path);
runCallbacks(callbacks, err, result);
});
}
: null;
this.provideSync = this._syncProvider
? (path, options) => {
return this._syncProvider.call(this._providerContext, path, options);
}
: null;
}
purge() {}
purgeParent() {}
}
/*
IDLE:
insert data: goto SYNC
SYNC:
before provide: run ticks
event loop tick: goto ASYNC_ACTIVE
ASYNC:
timeout: run tick, goto ASYNC_PASSIVE
ASYNC_PASSIVE:
before provide: run ticks
IDLE --[insert data]--> SYNC --[event loop tick]--> ASYNC_ACTIVE --[interval tick]-> ASYNC_PASSIVE
^ |
+---------[insert data]-------+
*/
const STORAGE_MODE_IDLE = 0;
const STORAGE_MODE_SYNC = 1;
const STORAGE_MODE_ASYNC = 2;
class CacheBackend {
/**
* @param {number} duration max cache duration of items
* @param {any} provider async method
* @param {any} syncProvider sync method
* @param {any} providerContext call context for the provider methods
*/
constructor(duration, provider, syncProvider, providerContext) {
this._duration = duration;
this._provider = provider;
this._syncProvider = syncProvider;
this._providerContext = providerContext;
/** @type {Map<string, (function(Error, any): void)[]>} */
this._activeAsyncOperations = new Map();
/** @type {Map<string, { err: Error, result: any, level: Set<string> }>} */
this._data = new Map();
/** @type {Set<string>[]} */
this._levels = [];
for (let i = 0; i < 10; i++) this._levels.push(new Set());
for (let i = 5000; i < duration; i += 500) this._levels.push(new Set());
this._currentLevel = 0;
this._tickInterval = Math.floor(duration / this._levels.length);
/** @type {STORAGE_MODE_IDLE | STORAGE_MODE_SYNC | STORAGE_MODE_ASYNC} */
this._mode = STORAGE_MODE_IDLE;
/** @type {NodeJS.Timeout | undefined} */
this._timeout = undefined;
/** @type {number | undefined} */
this._nextDecay = undefined;
this.provide = provider ? this.provide.bind(this) : null;
this.provideSync = syncProvider ? this.provideSync.bind(this) : null;
}
provide(path, options, callback) {
if (typeof options === "function") {
callback = options;
options = undefined;
}
if (typeof path !== "string") {
callback(new TypeError("path must be a string"));
return;
}
if (options) {
return this._provider.call(
this._providerContext,
path,
options,
callback
);
}
// When in sync mode we can move to async mode
if (this._mode === STORAGE_MODE_SYNC) {
this._enterAsyncMode();
}
// Check in cache
let cacheEntry = this._data.get(path);
if (cacheEntry !== undefined) {
if (cacheEntry.err) return nextTick(callback, cacheEntry.err);
return nextTick(callback, null, cacheEntry.result);
}
// Check if there is already the same operation running
let callbacks = this._activeAsyncOperations.get(path);
if (callbacks !== undefined) {
callbacks.push(callback);
return;
}
this._activeAsyncOperations.set(path, (callbacks = [callback]));
// Run the operation
this._provider.call(this._providerContext, path, (err, result) => {
this._activeAsyncOperations.delete(path);
this._storeResult(path, err, result);
// Enter async mode if not yet done
this._enterAsyncMode();
runCallbacks(callbacks, err, result);
});
}
provideSync(path, options) {
if (typeof path !== "string") {
throw new TypeError("path must be a string");
}
if (options) {
return this._syncProvider.call(this._providerContext, path, options);
}
// In sync mode we may have to decay some cache items
if (this._mode === STORAGE_MODE_SYNC) {
this._runDecays();
}
// Check in cache
let cacheEntry = this._data.get(path);
if (cacheEntry !== undefined) {
if (cacheEntry.err) throw cacheEntry.err;
return cacheEntry.result;
}
// Get all active async operations
// This sync operation will also complete them
const callbacks = this._activeAsyncOperations.get(path);
this._activeAsyncOperations.delete(path);
// Run the operation
// When in idle mode, we will enter sync mode
let result;
try {
result = this._syncProvider.call(this._providerContext, path);
} catch (err) {
this._storeResult(path, err, undefined);
this._enterSyncModeWhenIdle();
if (callbacks) runCallbacks(callbacks, err, undefined);
throw err;
}
this._storeResult(path, undefined, result);
this._enterSyncModeWhenIdle();
if (callbacks) runCallbacks(callbacks, undefined, result);
return result;
}
purge(what) {
if (!what) {
if (this._mode !== STORAGE_MODE_IDLE) {
this._data.clear();
for (const level of this._levels) {
level.clear();
}
this._enterIdleMode();
}
} else if (typeof what === "string") {
for (let [key, data] of this._data) {
if (key.startsWith(what)) {
this._data.delete(key);
data.level.delete(key);
}
}
if (this._data.size === 0) {
this._enterIdleMode();
}
} else {
for (let [key, data] of this._data) {
for (const item of what) {
if (key.startsWith(item)) {
this._data.delete(key);
data.level.delete(key);
break;
}
}
}
if (this._data.size === 0) {
this._enterIdleMode();
}
}
}
purgeParent(what) {
if (!what) {
this.purge();
} else if (typeof what === "string") {
this.purge(dirname(what));
} else {
const set = new Set();
for (const item of what) {
set.add(dirname(item));
}
this.purge(set);
}
}
_storeResult(path, err, result) {
if (this._data.has(path)) return;
const level = this._levels[this._currentLevel];
this._data.set(path, { err, result, level });
level.add(path);
}
_decayLevel() {
const nextLevel = (this._currentLevel + 1) % this._levels.length;
const decay = this._levels[nextLevel];
this._currentLevel = nextLevel;
for (let item of decay) {
this._data.delete(item);
}
decay.clear();
if (this._data.size === 0) {
this._enterIdleMode();
} else {
// @ts-ignore _nextDecay is always a number in sync mode
this._nextDecay += this._tickInterval;
}
}
_runDecays() {
while (
/** @type {number} */ (this._nextDecay) <= Date.now() &&
this._mode !== STORAGE_MODE_IDLE
) {
this._decayLevel();
}
}
_enterAsyncMode() {
let timeout = 0;
switch (this._mode) {
case STORAGE_MODE_ASYNC:
return;
case STORAGE_MODE_IDLE:
this._nextDecay = Date.now() + this._tickInterval;
timeout = this._tickInterval;
break;
case STORAGE_MODE_SYNC:
this._runDecays();
// @ts-ignore _runDecays may change the mode
if (this._mode === STORAGE_MODE_IDLE) return;
timeout = Math.max(
0,
/** @type {number} */ (this._nextDecay) - Date.now()
);
break;
}
this._mode = STORAGE_MODE_ASYNC;
const ref = setTimeout(() => {
this._mode = STORAGE_MODE_SYNC;
this._runDecays();
}, timeout);
if (ref.unref) ref.unref();
this._timeout = ref;
}
_enterSyncModeWhenIdle() {
if (this._mode === STORAGE_MODE_IDLE) {
this._mode = STORAGE_MODE_SYNC;
this._nextDecay = Date.now() + this._tickInterval;
}
}
_enterIdleMode() {
this._mode = STORAGE_MODE_IDLE;
this._nextDecay = undefined;
if (this._timeout) clearTimeout(this._timeout);
}
}
const createBackend = (duration, provider, syncProvider, providerContext) => {
if (duration > 0) {
return new CacheBackend(duration, provider, syncProvider, providerContext);
}
return new OperationMergerBackend(provider, syncProvider, providerContext);
};
module.exports = class CachedInputFileSystem {
constructor(fileSystem, duration) {
this.fileSystem = fileSystem;
this._lstatBackend = createBackend(
duration,
this.fileSystem.lstat,
this.fileSystem.lstatSync,
this.fileSystem
);
const lstat = this._lstatBackend.provide;
this.lstat = /** @type {FileSystem["lstat"]} */ (lstat);
const lstatSync = this._lstatBackend.provideSync;
this.lstatSync = /** @type {SyncFileSystem["lstatSync"]} */ (lstatSync);
this._statBackend = createBackend(
duration,
this.fileSystem.stat,
this.fileSystem.statSync,
this.fileSystem
);
const stat = this._statBackend.provide;
this.stat = /** @type {FileSystem["stat"]} */ (stat);
const statSync = this._statBackend.provideSync;
this.statSync = /** @type {SyncFileSystem["statSync"]} */ (statSync);
this._readdirBackend = createBackend(
duration,
this.fileSystem.readdir,
this.fileSystem.readdirSync,
this.fileSystem
);
const readdir = this._readdirBackend.provide;
this.readdir = /** @type {FileSystem["readdir"]} */ (readdir);
const readdirSync = this._readdirBackend.provideSync;
this.readdirSync = /** @type {SyncFileSystem["readdirSync"]} */ (readdirSync);
this._readFileBackend = createBackend(
duration,
this.fileSystem.readFile,
this.fileSystem.readFileSync,
this.fileSystem
);
const readFile = this._readFileBackend.provide;
this.readFile = /** @type {FileSystem["readFile"]} */ (readFile);
const readFileSync = this._readFileBackend.provideSync;
this.readFileSync = /** @type {SyncFileSystem["readFileSync"]} */ (readFileSync);
this._readJsonBackend = createBackend(
duration,
this.fileSystem.readJson ||
(this.readFile &&
((path, callback) => {
// @ts-ignore
this.readFile(path, (err, buffer) => {
if (err) return callback(err);
if (!buffer || buffer.length === 0)
return callback(new Error("No file content"));
let data;
try {
data = JSON.parse(buffer.toString("utf-8"));
} catch (e) {
return callback(e);
}
callback(null, data);
});
})),
this.fileSystem.readJsonSync ||
(this.readFileSync &&
(path => {
const buffer = this.readFileSync(path);
const data = JSON.parse(buffer.toString("utf-8"));
return data;
})),
this.fileSystem
);
const readJson = this._readJsonBackend.provide;
this.readJson = /** @type {FileSystem["readJson"]} */ (readJson);
const readJsonSync = this._readJsonBackend.provideSync;
this.readJsonSync = /** @type {SyncFileSystem["readJsonSync"]} */ (readJsonSync);
this._readlinkBackend = createBackend(
duration,
this.fileSystem.readlink,
this.fileSystem.readlinkSync,
this.fileSystem
);
const readlink = this._readlinkBackend.provide;
this.readlink = /** @type {FileSystem["readlink"]} */ (readlink);
const readlinkSync = this._readlinkBackend.provideSync;
this.readlinkSync = /** @type {SyncFileSystem["readlinkSync"]} */ (readlinkSync);
}
purge(what) {
this._statBackend.purge(what);
this._lstatBackend.purge(what);
this._readdirBackend.purgeParent(what);
this._readFileBackend.purge(what);
this._readlinkBackend.purge(what);
this._readJsonBackend.purge(what);
}
};