cachelot/lib/index.js

locking based inMemory cache

"use strict";
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
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        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
        step((generator = generator.apply(thisArg, _arguments || [])).next());
    });
};
var __generator = (this && this.__generator) || function (thisArg, body) {
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                case 0: case 1: t = op; break;
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    }
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.NewFrom = exports.New = exports.Cache = void 0;
var async_mutex_1 = require("async-mutex");
var mutex = new async_mutex_1.Mutex();
var DefaultExpiration = 0;
var NoExpiration = -1;
var Item = /** @class */ (function () {
    function Item(Object, Expiration) {
        this.Object = Object;
        this.Expiration = Expiration;
    }
    Item.prototype.Expired = function () {
        if (this.Expiration == 0) {
            return false;
        }
        return Date.now() > this.Expiration;
    };
    return Item;
}());
var Cache = /** @class */ (function () {
    function Cache(defaultExpiration, items) {
        this.defaultExpiration = defaultExpiration;
        this.items = items;
    }
    Cache.prototype.Set = function (k, x, d) {
        return __awaiter(this, void 0, void 0, function () {
            var e, release;
            return __generator(this, function (_a) {
                switch (_a.label) {
                    case 0:
                        // if d == 0 set to cache's default expiration
                        if (!d || d === DefaultExpiration) {
                            d = this.defaultExpiration;
                        }
                        if (d > 0) {
                            // TODO : proper date, now in ms epoch
                            e = Date.now() + d;
                        }
                        return [4 /*yield*/, mutex.acquire()];
                    case 1:
                        release = _a.sent();
                        this.items[k] = new Item(x, e);
                        release();
                        return [2 /*return*/];
                }
            });
        });
    };
    Cache.prototype.set = function (k, x, d) {
        var e;
        // if d == 0 set to cache's default expiration
        if (!d || d === DefaultExpiration) {
            d = this.defaultExpiration;
        }
        if (d > 0) {
            // TODO : proper date, now in ms epoch
            e = Date.now() + d;
        }
        //  no lock cuz callee is using the lock
        this.items[k] = new Item(x, e);
    };
    Cache.prototype.SetDefault = function (k, x) {
        this.Set(k, x, DefaultExpiration);
    };
    Cache.prototype.Get = function (k) {
        return __awaiter(this, void 0, void 0, function () {
            var release, item;
            return __generator(this, function (_a) {
                switch (_a.label) {
                    case 0: return [4 /*yield*/, mutex.acquire()];
                    case 1:
                        release = _a.sent();
                        item = this.items[k];
                        if (!item) {
                            release();
                            return [2 /*return*/, [null, false]];
                        }
                        if (item.Expiration > 0) {
                            if (Date.now() > item.Expiration) {
                                release();
                                return [2 /*return*/, [null, false]];
                            }
                        }
                        release();
                        return [2 /*return*/, [item.Object, true]];
                }
            });
        });
    };
    Cache.prototype.GetWithExpiration = function (k) {
        return __awaiter(this, void 0, void 0, function () {
            var release, item;
            return __generator(this, function (_a) {
                switch (_a.label) {
                    case 0: return [4 /*yield*/, mutex.acquire()];
                    case 1:
                        release = _a.sent();
                        item = this.items[k];
                        if (!item) {
                            release();
                            return [2 /*return*/, [null, 0, false]];
                        }
                        if (item.Expiration > 0) {
                            if (Date.now() > item.Expiration) {
                                release();
                                return [2 /*return*/, [null, 0, false]];
                            }
                            return [2 /*return*/, [item.Object, item.Expiration, true]];
                        }
                        release();
                        return [2 /*return*/, [item.Object, 0, true]];
                }
            });
        });
    };
    Cache.prototype.get = function (k) {
        var item = this.items[k];
        if (!item) {
            return [null, false];
        }
        if (item.Expiration > 0) {
            if (Date.now() > item.Expiration) {
                return [null, false];
            }
        }
        return [item.Object, true];
    };
    Cache.prototype.Add = function (k, x, d) {
        return __awaiter(this, void 0, void 0, function () {
            var release, _a, _, found;
            return __generator(this, function (_b) {
                switch (_b.label) {
                    case 0: return [4 /*yield*/, mutex.acquire()];
                    case 1:
                        release = _b.sent();
                        _a = this.get(k), _ = _a[0], found = _a[1];
                        if (found) {
                            release();
                            throw new Error("Item " + k + " already exists");
                        }
                        this.set(k, x, d);
                        release();
                        return [2 /*return*/, null];
                }
            });
        });
    };
    Cache.prototype.Replace = function (k, x, d) {
        return __awaiter(this, void 0, void 0, function () {
            var release, _a, _, found;
            return __generator(this, function (_b) {
                switch (_b.label) {
                    case 0: return [4 /*yield*/, mutex.acquire()];
                    case 1:
                        release = _b.sent();
                        _a = this.get(k), _ = _a[0], found = _a[1];
                        if (!found) {
                            release();
                            throw new Error("Item " + k + " doesn't exist");
                        }
                        this.set(k, x, d);
                        release();
                        return [2 /*return*/, null];
                }
            });
        });
    };
    Cache.prototype.Delete = function (k) {
        return __awaiter(this, void 0, void 0, function () {
            var release, _a, obj, evicted;
            return __generator(this, function (_b) {
                switch (_b.label) {
                    case 0: return [4 /*yield*/, mutex.acquire()];
                    case 1:
                        release = _b.sent();
                        _a = this.delete(k), obj = _a[0], evicted = _a[1];
                        release();
                        if (evicted) {
                            this.onEvicted(k, obj);
                        }
                        return [2 /*return*/];
                }
            });
        });
    };
    Cache.prototype.delete = function (k) {
        if (this.onEvicted) {
            var item = this.items[k];
            if (item) {
                delete this.items[k];
                return [item.Object, true];
            }
        }
        delete this.items[k];
        return [null, false];
    };
    Cache.prototype.DeleteExpired = function () {
        return __awaiter(this, void 0, void 0, function () {
            var evictedItems, now, release, k, v, _a, ov, evicted, i, v;
            return __generator(this, function (_b) {
                switch (_b.label) {
                    case 0:
                        evictedItems = [];
                        now = Date.now();
                        return [4 /*yield*/, mutex.acquire()];
                    case 1:
                        release = _b.sent();
                        for (k in this.items) {
                            v = this.items[k];
                            if (v.Expiration > 0 && now > v.Expiration) {
                                _a = this.delete(k), ov = _a[0], evicted = _a[1];
                                if (evicted) {
                                    evictedItems.push({ key: k, value: v });
                                }
                            }
                        }
                        release();
                        for (i = 0; i < evictedItems.length; i += 1) {
                            v = evictedItems[i];
                            this.onEvicted(v.key, v.value);
                        }
                        return [2 /*return*/];
                }
            });
        });
    };
    Cache.prototype.OnEvicted = function (fn) {
        return __awaiter(this, void 0, void 0, function () {
            var release;
            return __generator(this, function (_a) {
                switch (_a.label) {
                    case 0: return [4 /*yield*/, mutex.acquire()];
                    case 1:
                        release = _a.sent();
                        this.onEvicted = fn;
                        release();
                        return [2 /*return*/];
                }
            });
        });
    };
    Cache.prototype.Items = function () {
        return __awaiter(this, void 0, void 0, function () {
            var release, validItems, now, k, v;
            return __generator(this, function (_a) {
                switch (_a.label) {
                    case 0: return [4 /*yield*/, mutex.acquire()];
                    case 1:
                        release = _a.sent();
                        validItems = {};
                        now = Date.now();
                        for (k in this.items) {
                            v = this.items[k];
                            if (v.Expiration > 0 && now > v.Expiration) {
                                continue;
                            }
                            validItems[k] = v;
                        }
                        release();
                        return [2 /*return*/, validItems];
                }
            });
        });
    };
    Cache.prototype.ItemCount = function () {
        return __awaiter(this, void 0, void 0, function () {
            var release, length;
            return __generator(this, function (_a) {
                switch (_a.label) {
                    case 0: return [4 /*yield*/, mutex.acquire()];
                    case 1:
                        release = _a.sent();
                        length = Object.keys(this.items).length;
                        release();
                        return [2 /*return*/, length];
                }
            });
        });
    };
    Cache.prototype.Flush = function () {
        return __awaiter(this, void 0, void 0, function () {
            var release;
            return __generator(this, function (_a) {
                switch (_a.label) {
                    case 0: return [4 /*yield*/, mutex.acquire()];
                    case 1:
                        release = _a.sent();
                        this.items = {};
                        release();
                        return [2 /*return*/];
                }
            });
        });
    };
    Cache.prototype.stopJanitor = function () {
        this.janitor.stop = true;
    };
    Cache.prototype.runJanitor = function (interval) {
        this.janitor = new Janitor(interval, false);
        this.janitor.Run(this);
    };
    return Cache;
}());
exports.Cache = Cache;
var Janitor = /** @class */ (function () {
    function Janitor(Interval, stop) {
        this.Interval = Interval;
        this.stop = stop;
    }
    Janitor.prototype.Run = function (cache) {
        var _this = this;
        var ticker = setInterval(function () {
            if (_this.stop) {
                clearInterval(ticker);
                return;
            }
            cache.DeleteExpired();
        }, this.Interval);
    };
    return Janitor;
}());
function newCache(de, m) {
    if (de === 0) {
        de = NoExpiration;
    }
    var c = new Cache(de, m);
    return c;
}
function newCacheWithJanitor(de, ci, m) {
    var c = newCache(de, m);
    if (ci > 0) {
        c.runJanitor(ci);
    }
    return c;
}
function New(defaultExpiration, cleanUpInterval) {
    var items = {};
    return newCacheWithJanitor(defaultExpiration, cleanUpInterval, items);
}
exports.New = New;
function NewFrom(defaultExpiration, cleanUpInterval, items) {
    return newCacheWithJanitor(defaultExpiration, cleanUpInterval, items);
}
exports.NewFrom = NewFrom;
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