213 lines
6.4 KiB
JavaScript
213 lines
6.4 KiB
JavaScript
import { WeakLRUCache, clearKeptObjects } from './native.js';
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import { FAILED_CONDITION, ABORT, IF_EXISTS } from './write.js';
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import { UNMODIFIED } from './read.js';
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import { when } from './util/when.js';
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let getLastVersion, getLastTxnId;
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const mapGet = Map.prototype.get;
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export const CachingStore = (Store, env) => {
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let childTxnChanges
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return class LMDBStore extends Store {
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constructor(dbName, options) {
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super(dbName, options);
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if (!env.cacheCommitter) {
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env.cacheCommitter = true;
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this.on('aftercommit', ({ next, last, txnId }) => {
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do {
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let meta = next.meta;
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let store = meta && meta.store;
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if (store) {
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if (next.flag & FAILED_CONDITION)
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store.cache.delete(meta.key); // just delete it from the map
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else {
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let expirationPriority = meta.valueSize >> 10;
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let cache = store.cache;
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let entry = mapGet.call(cache, meta.key);
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if (entry) {
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entry.txnId = txnId;
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cache.used(entry, expirationPriority + 4); // this will enter it into the LRFU (with a little lower priority than a read)
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}
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}
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}
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} while (next != last && (next = next.next))
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});
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}
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this.db.cachingDb = this;
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if (options.cache.clearKeptInterval)
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options.cache.clearKeptObjects = clearKeptObjects;
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this.cache = new WeakLRUCache(options.cache);
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if (options.cache.validated)
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this.cache.validated = true;
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}
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get isCaching() {
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return true
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}
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get(id, options) {
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let value;
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if (this.cache.validated) {
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let entry = this.cache.get(id);
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if (entry) {
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let cachedValue = entry.value;
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if (entry.txnId != null) {
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value = super.get(id, { ifNotTxnId: entry.txnId, transaction: options && options.transaction });
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if (value === UNMODIFIED)
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return cachedValue;
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} else // with no txn id we do not validate; this is the state of a cached value after a write before it transacts
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return cachedValue;
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} else
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value = super.get(id, options);
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} else if (options && options.transaction) {
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return super.get(id, options);
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} else {
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value = this.cache.getValue(id);
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if (value !== undefined) {
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return value;
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}
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value = super.get(id);
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}
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if (value && typeof value === 'object' && !options && typeof id !== 'object') {
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let entry = this.cache.setValue(id, value, this.lastSize >> 10);
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if (this.useVersions) {
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entry.version = getLastVersion();
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}
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if (this.cache.validated)
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entry.txnId = getLastTxnId();
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}
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return value;
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}
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getEntry(id, options) {
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let entry, value;
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if (this.cache.validated) {
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entry = this.cache.get(id);
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if (entry) {
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if (entry.txnId != null) {
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value = super.get(id, { ifNotTxnId: entry.txnId, transaction: options && options.transaction });
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if (value === UNMODIFIED)
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return entry;
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} else // with no txn id we do not validate; this is the state of a cached value after a write before it transacts
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return entry;
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} else
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value = super.get(id, options);
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} else if (options && options.transaction) {
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return super.getEntry(id, options);
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} else {
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entry = this.cache.get(id);
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if (entry !== undefined) {
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return entry;
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}
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value = super.get(id);
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}
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if (value === undefined)
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return;
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if (value && typeof value === 'object' && !options && typeof id !== 'object') {
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entry = this.cache.setValue(id, value, this.lastSize >> 10);
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} else
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entry = { value };
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if (this.useVersions)
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entry.version = getLastVersion();
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if (this.cache.validated)
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entry.txnId = getLastTxnId();
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return entry;
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}
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putEntry(id, entry, ifVersion) {
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let result = super.put(id, entry.value, entry.version, ifVersion);
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if (typeof id === 'object')
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return result;
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if (result && result.then)
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this.cache.setManually(id, entry); // set manually so we can keep it pinned in memory until it is committed
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else // sync operation, immediately add to cache
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this.cache.set(id, entry);
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}
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put(id, value, version, ifVersion) {
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let result = super.put(id, value, version, ifVersion);
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if (typeof id !== 'object') {
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if (value && value['\x10binary-data\x02']) {
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// don't cache binary data, since it will be decoded on get
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this.cache.delete(id);
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return result;
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}
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// sync operation, immediately add to cache, otherwise keep it pinned in memory until it is committed
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let entry = this.cache.setValue(id, value, !result || result.isSync ? 0 : -1);
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if (childTxnChanges)
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childTxnChanges.add(id);
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if (version !== undefined)
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entry.version = typeof version === 'object' ? version.version : version;
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}
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return result;
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}
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putSync(id, value, version, ifVersion) {
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if (id !== 'object') {
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// sync operation, immediately add to cache, otherwise keep it pinned in memory until it is committed
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if (value && typeof value === 'object') {
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let entry = this.cache.setValue(id, value);
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if (childTxnChanges)
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childTxnChanges.add(id);
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if (version !== undefined) {
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entry.version = typeof version === 'object' ? version.version : version;
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}
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} else // it is possible that a value used to exist here
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this.cache.delete(id);
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}
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return super.putSync(id, value, version, ifVersion);
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}
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remove(id, ifVersion) {
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this.cache.delete(id);
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return super.remove(id, ifVersion);
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}
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removeSync(id, ifVersion) {
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this.cache.delete(id);
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return super.removeSync(id, ifVersion);
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}
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clearAsync(callback) {
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this.cache.clear();
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return super.clearAsync(callback);
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}
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clearSync() {
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this.cache.clear();
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super.clearSync();
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}
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childTransaction(callback) {
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return super.childTransaction(() => {
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let cache = this.cache;
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let previousChanges = childTxnChanges;
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try {
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childTxnChanges = new Set();
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return when(callback(), (result) => {
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if (result === ABORT)
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return abort();
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childTxnChanges = previousChanges;
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return result;
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}, abort);
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} catch(error) {
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abort(error);
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}
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function abort(error) {
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// if the transaction was aborted, remove all affected entries from cache
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for (let id of childTxnChanges)
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cache.delete(id);
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childTxnChanges = previousChanges;
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if (error)
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throw error;
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else
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return ABORT;
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}
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});
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}
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doesExist(key, versionOrValue) {
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let entry = this.cache.get(key);
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if (entry) {
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if (versionOrValue == null) {
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return versionOrValue !== null;
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} else if (this.useVersions) {
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return versionOrValue === IF_EXISTS || entry.version === versionOrValue;
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}
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}
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return super.doesExist(key, versionOrValue);
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}
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};
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};
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export function setGetLastVersion(get, getTxnId) {
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getLastVersion = get;
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getLastTxnId = getTxnId;
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}
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