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Adds support for different replacementStrategies & ... #4

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d5268c8
Adds support for different replacementStrategies
Oct 14, 2015
e8177da
Revert: dist changes
Oct 15, 2015
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235 changes: 161 additions & 74 deletions src/index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -63,6 +63,90 @@ let _keySet = collection => {
return keySet;
};

/**
* Replacement Strategies must implement onGet, onPut and onRemove callbacks and priorityQueue
* onGet -> Called after an item is retrieved from the cache by the client
* onPut -> Called after an item is added to the cache for the first time by the client.
* Also called when reinitializing a cache from localStorage.
* onRemove -> Called after an item is removed from the cache by the client
* priorityQueue -> Retrieves an object that implements the following API
* priorityQueue.size() - the number of items being tracked
* priorityQueue.peek() - which returns next item to remove
* priorityQueue.removeAll() - which resets underlying tracking mechanism
*/
class BaseLruStrategy {
constructor() {
this.$$lruHeap = new BinaryHeap(function (x) {
return x.accessed;
}, utils.equals);
}

priorityQueue() {
return this.$$lruHeap;
}
}

class DefaultLruStrategy extends BaseLruStrategy {
constructor() {
super();
}

onGet(key, item) {
let now = Date.now();
this.$$lruHeap.remove(item);
item.accessed = now;
this.$$lruHeap.push(item);
return true;
}
onPut(key, item) {
this.$$lruHeap.push(item);
}
onRemove(key, item) {
this.$$lruHeap.remove(item);
}
}

class StorageLruStrategy extends BaseLruStrategy {
constructor() {
super();
}

onGet(key, item) {
let now = Date.now();
this.$$lruHeap.remove({
key : key,
accessed: item.accessed
});
item.accessed = now;
this.$$lruHeap.push({
key : key,
accessed: now
});
return true;
}
onPut(key, item) {
this.$$lruHeap.push({
key : key,
accessed: item.accessed
});
}
onRemove(key, item) {
this.$$lruHeap.remove({
key : key,
accessed: item.accessed
});
}
}

let lru = {
default() {
return new DefaultLruStrategy();
},
withStorage() {
return new StorageLruStrategy();
}
};

let defaults = {
capacity: Number.MAX_VALUE,
maxAge: Number.MAX_VALUE,
Expand All @@ -75,7 +159,8 @@ let defaults = {
disabled: false,
storagePrefix: 'cachefactory.caches.',
storeOnResolve: false,
storeOnReject: false
storeOnReject: false,
replacementStrategy: lru
};

let caches = {};
Expand All @@ -90,8 +175,8 @@ let createCache = (cacheId, options) => {
let $$data = {};
let $$promises = {};
let $$storage = null;
let $$replacementStrategy = null;
let $$expiresHeap = new BinaryHeap(x => x.expires, utils.equals);
let $$lruHeap = new BinaryHeap(x => x.accessed, utils.equals);

let cache = caches[cacheId] = {

Expand All @@ -107,7 +192,7 @@ let createCache = (cacheId, options) => {
}
$$storage = null;
$$data = null;
$$lruHeap = null;
$$replacementStrategy = null;
$$expiresHeap = null;
this.$$prefix = null;
delete caches[this.$$id];
Expand Down Expand Up @@ -151,48 +236,15 @@ let createCache = (cacheId, options) => {
throw new Error('options.onExpire must be a function!');
}

let item;

if ($$storage) {
if ($$promises[key]) {
return $$promises[key];
}

let itemJson = $$storage().getItem(`${this.$$prefix}.data.${key}`);

if (itemJson) {
item = utils.fromJson(itemJson);
} else {
return;
}
} else {
if (!(key in $$data)) {
return;
}

item = $$data[key];
let item = this.doGetItem(key);
if (!item || _isPromiseLike(item)) {
return item;
}

let value = item.value;
let now = new Date().getTime();

if ($$storage) {
$$lruHeap.remove({
key: key,
accessed: item.accessed
});
item.accessed = now;
$$lruHeap.push({
key: key,
accessed: now
});
} else {
$$lruHeap.remove(item);
item.accessed = now;
$$lruHeap.push(item);
}
var modified = $$replacementStrategy.onGet(key, item);

if (this.$$deleteOnExpire === 'passive' && 'expires' in item && item.expires < now) {
let value = item.value;
if (this.$$deleteOnExpire === 'passive' && 'expires' in item && item.expires < Date.now()) {
this.remove(key);

if (this.$$onExpire) {
Expand All @@ -201,7 +253,7 @@ let createCache = (cacheId, options) => {
options.onExpire.call(this, key, item.value);
}
value = undefined;
} else if ($$storage) {
} else if ($$storage && modified) {
$$storage().setItem(`${this.$$prefix}.data.${key}`, JSON.stringify(item));
}

Expand Down Expand Up @@ -251,7 +303,7 @@ let createCache = (cacheId, options) => {
storageMode: this.$$storageMode,
storageImpl: $$storage ? $$storage() : undefined,
disabled: !!this.$$disabled,
size: $$lruHeap && $$lruHeap.size() || 0
size: $$replacementStrategy && $$replacementStrategy.priorityQueue().size() || 0
};
}
},
Expand Down Expand Up @@ -359,10 +411,7 @@ let createCache = (cacheId, options) => {
expires: item.expires
});
// Add to lru heap
$$lruHeap.push({
key: key,
accessed: item.accessed
});
$$replacementStrategy.onPut(key, item);
// Set item
$$storage().setItem(`${this.$$prefix}.data.${key}`, JSON.stringify(item));
let exists = false;
Expand All @@ -384,15 +433,16 @@ let createCache = (cacheId, options) => {
// Add to expires heap
$$expiresHeap.push(item);
// Add to lru heap
$$lruHeap.push(item);
$$replacementStrategy.onPut(key, item);
// Set item
$$data[key] = item;
delete $$promises[key];
}

// Handle exceeded capacity
if ($$lruHeap.size() > this.$$capacity) {
this.remove($$lruHeap.peek().key);
let replacementQueue = $$replacementStrategy.priorityQueue();
if (replacementQueue.size() > this.$$capacity) {
this.remove(replacementQueue.peek().key);
}

return value;
Expand All @@ -406,10 +456,7 @@ let createCache = (cacheId, options) => {

if (itemJson) {
let item = utils.fromJson(itemJson);
$$lruHeap.remove({
key: key,
accessed: item.accessed
});
$$replacementStrategy.onRemove(key, item);
$$expiresHeap.remove({
key: key,
expires: item.expires
Expand All @@ -427,7 +474,7 @@ let createCache = (cacheId, options) => {
}
} else {
let value = $$data[key] ? $$data[key].value : undefined;
$$lruHeap.remove($$data[key]);
$$replacementStrategy.onRemove(key, $$data[key]);
$$expiresHeap.remove($$data[key]);
$$data[key] = null;
delete $$data[key];
Expand All @@ -436,9 +483,11 @@ let createCache = (cacheId, options) => {
},

removeAll() {
if ($$replacementStrategy) {
$$replacementStrategy.priorityQueue().removeAll();
}
$$expiresHeap.removeAll();
if ($$storage) {
$$lruHeap.removeAll();
$$expiresHeap.removeAll();
let keysJson = $$storage().getItem(`${this.$$prefix}.keys`);

if (keysJson) {
Expand All @@ -450,8 +499,6 @@ let createCache = (cacheId, options) => {
}
$$storage().setItem(`${this.$$prefix}.keys`, JSON.stringify([]));
} else {
$$lruHeap.removeAll();
$$expiresHeap.removeAll();
for (var key in $$data) {
$$data[key] = null;
}
Expand Down Expand Up @@ -523,8 +570,9 @@ let createCache = (cacheId, options) => {
this.$$capacity = capacity;
}
let removed = {};
while ($$lruHeap.size() > this.$$capacity) {
removed[$$lruHeap.peek().key] = this.remove($$lruHeap.peek().key);
let replacementQueue = $$replacementStrategy.priorityQueue();
while (replacementQueue.size() > this.$$capacity) {
removed[replacementQueue.peek().key] = this.remove(replacementQueue.peek().key);
}
return removed;
},
Expand Down Expand Up @@ -632,9 +680,9 @@ let createCache = (cacheId, options) => {
}

if ('storageMode' in cacheOptions || 'storageImpl' in cacheOptions) {
this.setStorageMode(cacheOptions.storageMode || defaults.storageMode, cacheOptions.storageImpl || defaults.storageImpl);
this.setStorageMode(cacheOptions.storageMode || defaults.storageMode, cacheOptions.storageImpl || defaults.storageImpl, cacheOptions.replacementStrategy || defaults.replacementStrategy);
} else if (strict) {
this.setStorageMode(defaults.storageMode, defaults.storageImpl);
this.setStorageMode(defaults.storageMode, defaults.storageImpl, defaults.replacementStrategy);
}

if ('storeOnResolve' in cacheOptions) {
Expand Down Expand Up @@ -708,7 +756,29 @@ let createCache = (cacheId, options) => {
}
},

setStorageMode(storageMode, storageImpl) {
doGetItem(key) {
if ($$storage) {
if ($$promises[key]) {
return $$promises[key];
}

let itemJson = $$storage().getItem(this.$$prefix + '.data.' + key);

if (itemJson) {
return utils.fromJson(itemJson);
} else {
return;
}
} else {
if (!(key in $$data)) {
return;
}

return $$data[key];
}
},

setStorageMode(storageMode, storageImpl, replacementStrategy) {
if (!utils.isString(storageMode)) {
throw new Error('storageMode must be a string!');
} else if (storageMode !== 'memory' && storageMode !== 'localStorage' && storageMode !== 'sessionStorage') {
Expand All @@ -718,18 +788,20 @@ let createCache = (cacheId, options) => {
let shouldReInsert = false;
let items = {};

let keys = this.keys();
if (typeof this.$$storageMode === 'string' && this.$$storageMode !== storageMode) {
let keys = this.keys();

if (keys.length) {
for (var i = 0; i < keys.length; i++) {
items[keys[i]] = this.get(keys[i]);
}
for (i = 0; i < keys.length; i++) {
this.remove(keys[i]);
if (keys.length) {
for (var i = 0; i < keys.length; i++) {
items[keys[i]] = this.get(keys[i]);
}
for (i = 0; i < keys.length; i++) {
this.remove(keys[i]);
}
shouldReInsert = true;
}
shouldReInsert = true;
}

this.$$storageMode = storageMode;

if (storageImpl) {
Expand Down Expand Up @@ -763,10 +835,25 @@ let createCache = (cacheId, options) => {
}
}

$$replacementStrategy = $$storage ? replacementStrategy.withStorage() : replacementStrategy.default();

if (shouldReInsert) {
for (var key in items) {
this.put(key, items[key]);
}
} else if ($$storage) {
let keys = this.keys();
if (keys.length) {
for (var j = 0; j < keys.length; j++) {
let k = keys[j];
let item = this.doGetItem(k);
$$replacementStrategy.onPut(k, item);
$$expiresHeap.push({
key: k,
expires: item.expires
});
}
}
}
},

Expand Down
1 change: 1 addition & 0 deletions test/unit/DSCacheFactory/index.info.test.js
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@ describe('CacheFactory.info()', function () {
assert.equal(info.recycleFreq, CACHE_DEFAULTS.recycleFreq);
assert.equal(info.storageMode, CACHE_DEFAULTS.storageMode);
assert.equal(info.storageImpl, CACHE_DEFAULTS.storageImpl);
assert.isNotNull(info.replacementStrategy);

assert.equal(info.caches.cache.id, caches[0].info().id);
assert.equal(info.caches.cache.capacity, caches[0].info().capacity);
Expand Down