23376498872

Committed 21 Mar 2026 09:14AM UTC coverage: 97.698% (-0.1%) from 97.826%

Build # 23376498872

Build Type

Pull #254

github

Committed by

web-flow

Commit Message

Merge 81e06bf3f into 28d4e34f0

Pull Request Pull Request #254: iterateRange: use k-way partition merge by sequenceNumber when no index specified

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615 of 652 branches covered (94.33%)

Branch coverage included in aggregate %.

41 of 42 new or added lines in 2 files covered. (97.62%)

4 existing lines in 2 files now uncovered.

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97.07

/src/Storage/ReadableStorage.js

const fs = require('fs');
const path = require('path');
const events = require('events');
const Partition = require('../Partition');
const Index = require('../Index');
const { assert, createHmac, matches, wrapAndCheck, buildMetadataForMatcher } = require('../util');

const DEFAULT_READ_BUFFER_SIZE = 4 * 1024;

/**
 * Reverses the items of an iterable
 * @param {Generator|Iterable} iterator
 * @returns {Generator<*>}
 */
function *reverse(iterator) {
    const items = Array.from(iterator);
    for (let i = items.length - 1; i >= 0; i--) {
        yield items[i];
    }
}

/**
 * @typedef {object|function(object):boolean} Matcher
 */

/**
 * An append-only storage with highly performant positional range scans.
 * It's highly optimized for an event-store and hence does not support compaction or data-rewrite, nor any querying
 */
class ReadableStorage extends events.EventEmitter {

    /**
     * @param {string} [storageName] The name of the storage.
     * @param {object} [config] An object with storage parameters.
     * @param {object} [config.serializer] A serializer object with methods serialize(document) and deserialize(data).
     * @param {function(object): string} config.serializer.serialize Default is JSON.stringify.
     * @param {function(string): object} config.serializer.deserialize Default is JSON.parse.
     * @param {string} [config.dataDirectory] The path where the storage data should reside. Default '.'.
     * @param {string} [config.indexDirectory] The path where the indexes should be stored. Defaults to dataDirectory.
     * @param {string} [config.indexFile] The name of the primary index. Default '{storageName}.index'.
     * @param {number} [config.readBufferSize] Size of the read buffer in bytes. Default 4096.
     * @param {object} [config.indexOptions] An options object that should be passed to all indexes on construction.
     * @param {string} [config.hmacSecret] A private key that is used to verify matchers retrieved from indexes.
     * @param {object} [config.metadata] A metadata object to be stored in all partitions belonging to this storage.
     */
    constructor(storageName = 'storage', config = {}) {
        super();
        if (typeof storageName !== 'string') {
            config = storageName;
            storageName = undefined;
        }

        this.storageFile = storageName || 'storage';
        const defaults = {
            serializer: { serialize: JSON.stringify, deserialize: JSON.parse },
            dataDirectory: '.',
            indexFile: this.storageFile + '.index',
            indexOptions: {},
            hmacSecret: '',
            metadata: {}
        };
        config = Object.assign(defaults, config);
        this.serializer = config.serializer;

        this.hmac = createHmac(config.hmacSecret);

        this.dataDirectory = path.resolve(config.dataDirectory);

        this.initializeIndexes(config);
        this.scanPartitions(config);
    }

    /**
     * @protected
     * @param {string} name
     * @param {object} [options]
     * @returns {{ index: ReadableIndex, matcher?: Matcher }}
     */
    createIndex(name, options = {}) {
        /** @type ReadableIndex */
        const index = new Index.ReadOnly(name, options);
        return { index };
    }

    /**
     * @protected
     * @param {string} name
     * @param {object} [options]
     * @returns {ReadablePartition}
     */
    createPartition(name, options = {}) {
        return new Partition.ReadOnly(name, options);
    }

    /**
     * Create/open the primary index and build the base configuration for all secondary indexes.
     *
     * @private
     * @param {object} config The configuration object
     * @returns void
     */
    initializeIndexes(config) {
        this.indexDirectory = path.resolve(config.indexDirectory || this.dataDirectory);

        this.indexOptions = config.indexOptions;
        this.indexOptions.dataDirectory = this.indexDirectory;
        // Safety precaution to prevent accidentally restricting main index
        delete this.indexOptions.matcher;
        const { index } = this.createIndex(config.indexFile, this.indexOptions);
        this.index = index;
        this.secondaryIndexes = {};
        this.readonlyIndexes = {};
    }

    /**
     * The amount of documents in the storage.
     * @returns {number}
     */
    get length() {
        return this.index.length;
    }

    /**
     * Scan the data directory for all existing partitions.
     * Every file beginning with the storageFile name is considered a partition.
     *
     * @private
     * @param {object} config The configuration object containing options for the partitions.
     * @returns void
     */
    scanPartitions(config) {
        const defaults = {
            readBufferSize: DEFAULT_READ_BUFFER_SIZE
        };
        this.partitionConfig = Object.assign(defaults, config);
        this.partitions = Object.create(null);

        const files = fs.readdirSync(this.dataDirectory);
        for (let file of files) {
            if (file.substr(-6) === '.index') continue;
            if (file.substr(-7) === '.branch') continue;
            if (file.substr(-5) === '.lock') continue;
            if (file.substr(0, this.storageFile.length) !== this.storageFile) continue;

            const partition = this.createPartition(file, this.partitionConfig);
            this.partitions[partition.id] = partition;
        }
    }

    /**
     * Open the storage and indexes and create read and write buffers eagerly.
     * Will emit an 'opened' event if finished.
     *
     * @api
     * @returns {boolean}
     */
    open() {
        this.index.open();

        this.forEachSecondaryIndex(index => index.open());

        this.emit('opened');
        return true;
    }

    /**
     * Close the storage and frees up all resources.
     * Will emit a 'closed' event when finished.
     *
     * @api
     * @returns void
     */
    close() {
        this.index.close();
        this.forEachSecondaryIndex(index => index.close());
        for (let index of Object.values(this.readonlyIndexes)) {
            index.close();
        }
        this.forEachPartition(partition => partition.close());
        this.emit('closed');
    }

    /**
     * Get a partition either by name or by id.
     * If a partition with the given name does not exist, a new one will be created.
     * If a partition with the given id does not exist, an error is thrown.
     *
     * @protected
     * @param {string|number} partitionIdentifier The partition name or the partition Id
     * @returns {ReadablePartition}
     * @throws {Error} If an id is given and no such partition exists.
     */
    getPartition(partitionIdentifier) {
        assert(partitionIdentifier in this.partitions, `Partition #${partitionIdentifier} does not exist.`);

        this.partitions[partitionIdentifier].open();
        return this.partitions[partitionIdentifier];
    }

    /**
     * @protected
     * @param {number} partitionId The partition to read from.
     * @param {number} position The file position to read from.
     * @param {number} [size] The expected byte size of the document at the given position.
     * @returns {object} The document stored at the given position.
     * @throws {Error} if the document at the given position can not be deserialized.
     */
    readFrom(partitionId, position, size) {
        const partition = this.getPartition(partitionId);
        const data = partition.readFrom(position, size);
        return this.serializer.deserialize(data);
    }

    /**
     * Read a single document from the given position, in the full index or in the provided index.
     *
     * @api
     * @param {number} number The 1-based document number (inside the given index) to read.
     * @param {ReadableIndex} [index] The index to use for finding the document position.
     * @returns {object} The document at the given position inside the index.
     */
    read(number, index) {
        index = index || this.index;

        if (!index.isOpen()) {
            index.open();
        }

        const entry = index.get(number);
        if (entry === false) {
            return false;
        }

        return this.readFrom(entry.partition, entry.position, entry.size);
    }

    /**
     * Read a range of documents from the given position range, in the provided index or across all partitions.
     * When no index is given, iterates all partitions directly and returns documents ordered by their
     * sequenceNumber, allowing reconstruction of insertion order without a global index.
     * Returns a generator in order to reduce memory usage and be able to read lots of documents with little latency.
     *
     * @api
     * @param {number} from The 1-based document number (inclusive) to start reading from.
     * @param {number} [until] The 1-based document number (inclusive) to read until. Defaults to index.length.
     * @param {ReadableIndex} [index] The index to use for finding the documents in the range. If not given, iterates all partitions ordered by sequenceNumber.
     * @returns {Generator<object>} A generator that will read each document in the range one by one.
     */
    *readRange(from, until = -1, index = null) {
        const lengthSource = index || this.index;
        if (!lengthSource.isOpen()) {
            lengthSource.open();
        }

        const readFrom = wrapAndCheck(from, lengthSource.length);
        const readUntil = wrapAndCheck(until, lengthSource.length);
        assert(readFrom > 0 && readUntil > 0, `Range scan error for range ${from} - ${until}.`);

        if (readFrom > readUntil) {
            const batchSize = 10;
            let batchUntil = readFrom;
            while (batchUntil > readUntil) {
                const batchFrom = Math.max(readUntil, batchUntil - batchSize);
                yield* reverse(this.iterateRange(batchFrom, batchUntil, index));
                batchUntil = batchFrom - 1;
            }
            return undefined;
        }

        yield* this.iterateRange(readFrom, readUntil, index);
    }

    /**
     * Iterate all documents in this storage in range from to until.
     * If an index is provided, uses it to look up document positions; otherwise iterates all partitions
     * directly and merges them in sequenceNumber order.
     * @private
     * @param {number} from
     * @param {number} until
     * @param {ReadableIndex|null} index
     * @returns {Generator<object>}
     */
    *iterateRange(from, until, index) {
        if (index !== null) {
            const entries = index.range(from, until);
            for (let entry of entries) {
                const document = this.readFrom(entry.partition, entry.position, entry.size);
                yield document;
            }
            return;
        }

        // No index: iterate all partitions and merge documents by sequenceNumber.
        // Document header sequenceNumber is 0-based; from/until are 1-based index positions.
        yield* this.iteratePartitionsBySequenceNumber(from - 1, until - 1);
    }

    /**
     * Iterate documents across all partitions in sequenceNumber order using a k-way merge.
     * SequenceNumbers stored in document headers are 0-based.
     * @private
     * @param {number} fromSeq The 0-based sequenceNumber to start from (inclusive).
     * @param {number} untilSeq The 0-based sequenceNumber to read until (inclusive).
     * @returns {Generator<object>}
     */
    *iteratePartitionsBySequenceNumber(fromSeq, untilSeq) {
        const iterators = [];

        for (const partition of Object.values(this.partitions)) {
            if (!partition.isOpen()) {
                partition.open();
            }
            const gen = partition.readAllWithHeaders();

            // Advance to the first document with sequenceNumber >= fromSeq
            let result = gen.next();
            while (!result.done && result.value.sequenceNumber < fromSeq) {
                result = gen.next();
            }

            if (!result.done && result.value.sequenceNumber <= untilSeq) {
                iterators.push({ gen, current: result.value });
            }
        }

        // K-way merge: at each step, yield the document with the smallest sequenceNumber
        while (iterators.length > 0) {
            let minIdx = 0;
            for (let i = 1; i < iterators.length; i++) {
                if (iterators[i].current.sequenceNumber < iterators[minIdx].current.sequenceNumber) {
                    minIdx = i;
                }
            }

            yield this.serializer.deserialize(iterators[minIdx].current.data);

            const next = iterators[minIdx].gen.next();
            if (!next.done && next.value.sequenceNumber <= untilSeq) {
                iterators[minIdx].current = next.value;
            } else {
                iterators.splice(minIdx, 1);
            }
        }
    }

    /**
     * Open an existing readonly index for reading, without registering it in the secondary indexes write path.
     * Use this for indexes whose files carry a status marker (e.g. `stream-foo.closed.index`).
     *
     * @api
     * @param {string} name The readonly index name (e.g. 'stream-foo.closed').
     * @returns {ReadableIndex}
     * @throws {Error} if the readonly index does not exist.
     */
    openReadonlyIndex(name) {
        if (name in this.readonlyIndexes) {
            return this.readonlyIndexes[name];
        }
        const indexName = this.storageFile + '.' + name + '.index';
        assert(fs.existsSync(path.join(this.indexDirectory, indexName)), `Index "${name}" does not exist.`);
        const { index } = this.createIndex(indexName, Object.assign({}, this.indexOptions));
        index.open();
        this.readonlyIndexes[name] = index;
        return index;
    }

    /**
     * Open an existing index.
     *
     * @api
     * @param {string} name The index name.
     * @param {Matcher} [matcher] The matcher object or function that the index needs to have been defined with. If not given it will not be validated.
     * @returns {ReadableIndex}
     * @throws {Error} if the index with that name does not exist.
     * @throws {Error} if the HMAC for the matcher does not match.
     */
    openIndex(name, matcher) {
        if (name === '_all') {
            return this.index;
        }
        if (name in this.secondaryIndexes) {
            return this.secondaryIndexes[name].index;
        }

        const indexName = this.storageFile + '.' + name + '.index';
        assert(fs.existsSync(path.join(this.indexDirectory, indexName)), `Index "${name}" does not exist.`);

        const metadata = buildMetadataForMatcher(matcher, this.hmac);
        let { index } = this.secondaryIndexes[name] = this.createIndex(indexName, Object.assign({}, this.indexOptions, { metadata }));

        index.open();
        return index;
    }

    /**
     * Helper method to iterate over all documents.
     *
     * @protected
     * @param {function(object, EntryInterface)} iterationHandler
     */
    forEachDocument(iterationHandler) {
        /* istanbul ignore if  */
        if (typeof iterationHandler !== 'function') {
            return;
        }

        const entries = this.index.all();

        for (let entry of entries) {
            const document = this.readFrom(entry.partition, entry.position, entry.size);
            iterationHandler(document, entry);
        }
    }

    /**
     * Helper method to iterate over all secondary indexes.
     *
     * @protected
     * @param {function(ReadableIndex, string)} iterationHandler
     * @param {object} [matchDocument] If supplied, only indexes the document matches on will be iterated.
     */
    forEachSecondaryIndex(iterationHandler, matchDocument) {
        /* istanbul ignore if  */
        if (typeof iterationHandler !== 'function') {
            return;
        }

        for (let indexName of Object.keys(this.secondaryIndexes)) {
            if (!matchDocument || matches(matchDocument, this.secondaryIndexes[indexName].matcher)) {
                iterationHandler(this.secondaryIndexes[indexName].index, indexName);
            }
        }
    }

    /**
     * Helper method to iterate over all partitions.
     *
     * @protected
     * @param {function(ReadablePartition)} iterationHandler
     */
    forEachPartition(iterationHandler) {
        /* istanbul ignore if  */
        if (typeof iterationHandler !== 'function') {
            return;
        }

        for (let partition of Object.keys(this.partitions)) {
            iterationHandler(this.partitions[partition]);
        }
    }

}

module.exports = ReadableStorage;
module.exports.matches = matches;

1	const fs = require('fs');	4✔
2	const path = require('path');	4✔
3	const events = require('events');	4✔
4	const Partition = require('../Partition');	4✔
5	const Index = require('../Index');	4✔
6	const { assert, createHmac, matches, wrapAndCheck, buildMetadataForMatcher } = require('../util');	4✔
7
8	const DEFAULT_READ_BUFFER_SIZE = 4 * 1024;	4✔
9
10	/**
11	* Reverses the items of an iterable
12	* @param {Generator\|Iterable} iterator
13	* @returns {Generator<*>}
14	*/
15	function *reverse(iterator) {
16	const items = Array.from(iterator);	60✔
17	for (let i = items.length - 1; i >= 0; i--) {	60✔
18	yield items[i];	532✔
19	}
20	}
21
22	/**
23	* @typedef {object\|function(object):boolean} Matcher
24	*/
25
26	/**
27	* An append-only storage with highly performant positional range scans.
28	* It's highly optimized for an event-store and hence does not support compaction or data-rewrite, nor any querying
29	*/
30	class ReadableStorage extends events.EventEmitter {
31
32	/**
33	* @param {string} [storageName] The name of the storage.
34	* @param {object} [config] An object with storage parameters.
35	* @param {object} [config.serializer] A serializer object with methods serialize(document) and deserialize(data).
36	* @param {function(object): string} config.serializer.serialize Default is JSON.stringify.
37	* @param {function(string): object} config.serializer.deserialize Default is JSON.parse.
38	* @param {string} [config.dataDirectory] The path where the storage data should reside. Default '.'.
39	* @param {string} [config.indexDirectory] The path where the indexes should be stored. Defaults to dataDirectory.
40	* @param {string} [config.indexFile] The name of the primary index. Default '{storageName}.index'.
41	* @param {number} [config.readBufferSize] Size of the read buffer in bytes. Default 4096.
42	* @param {object} [config.indexOptions] An options object that should be passed to all indexes on construction.
43	* @param {string} [config.hmacSecret] A private key that is used to verify matchers retrieved from indexes.
44	* @param {object} [config.metadata] A metadata object to be stored in all partitions belonging to this storage.
45	*/
46	constructor(storageName = 'storage', config = {}) {	416!
47	super();	752✔
48	if (typeof storageName !== 'string') {	752✔
49	config = storageName;	52✔
50	storageName = undefined;	52✔
51	}
52
53	this.storageFile = storageName \|\| 'storage';	752✔
54	const defaults = {	752✔
55	serializer: { serialize: JSON.stringify, deserialize: JSON.parse },
56	dataDirectory: '.',
57	indexFile: this.storageFile + '.index',
58	indexOptions: {},
59	hmacSecret: '',
60	metadata: {}
61	};
62	config = Object.assign(defaults, config);	752✔
63	this.serializer = config.serializer;	752✔
64
65	this.hmac = createHmac(config.hmacSecret);	752✔
66
67	this.dataDirectory = path.resolve(config.dataDirectory);	752✔
68
69	this.initializeIndexes(config);	752✔
70	this.scanPartitions(config);	748✔
71	}
72
73	/**
74	* @protected
75	* @param {string} name
76	* @param {object} [options]
77	* @returns {{ index: ReadableIndex, matcher?: Matcher }}
78	*/
79	createIndex(name, options = {}) {	×
80	/** @type ReadableIndex */
81	const index = new Index.ReadOnly(name, options);	112✔
82	return { index };	108✔
83	}
84
85	/**
86	* @protected
87	* @param {string} name
88	* @param {object} [options]
89	* @returns {ReadablePartition}
90	*/
91	createPartition(name, options = {}) {	×
92	return new Partition.ReadOnly(name, options);	40✔
93	}
94
95	/**
96	* Create/open the primary index and build the base configuration for all secondary indexes.
97	*
98	* @private
99	* @param {object} config The configuration object
100	* @returns void
101	*/
102	initializeIndexes(config) {
103	this.indexDirectory = path.resolve(config.indexDirectory \|\| this.dataDirectory);	752✔
104
105	this.indexOptions = config.indexOptions;	752✔
106	this.indexOptions.dataDirectory = this.indexDirectory;	752✔
107	// Safety precaution to prevent accidentally restricting main index
108	delete this.indexOptions.matcher;	752✔
109	const { index } = this.createIndex(config.indexFile, this.indexOptions);	752✔
110	this.index = index;	748✔
111	this.secondaryIndexes = {};	748✔
112	this.readonlyIndexes = {};	748✔
113	}
114
115	/**
116	* The amount of documents in the storage.
117	* @returns {number}
118	*/
119	get length() {
120	return this.index.length;	3,348✔
121	}
122
123	/**
124	* Scan the data directory for all existing partitions.
125	* Every file beginning with the storageFile name is considered a partition.
126	*
127	* @private
128	* @param {object} config The configuration object containing options for the partitions.
129	* @returns void
130	*/
131	scanPartitions(config) {
132	const defaults = {	748✔
133	readBufferSize: DEFAULT_READ_BUFFER_SIZE
134	};
135	this.partitionConfig = Object.assign(defaults, config);	748✔
136	this.partitions = Object.create(null);	748✔
137
138	const files = fs.readdirSync(this.dataDirectory);	748✔
139	for (let file of files) {	748✔
140	if (file.substr(-6) === '.index') continue;	956✔
141	if (file.substr(-7) === '.branch') continue;	440!
142	if (file.substr(-5) === '.lock') continue;	440✔
143	if (file.substr(0, this.storageFile.length) !== this.storageFile) continue;	356✔
144
145	const partition = this.createPartition(file, this.partitionConfig);	76✔
146	this.partitions[partition.id] = partition;	76✔
147	}
148	}
149
150	/**
151	* Open the storage and indexes and create read and write buffers eagerly.
152	* Will emit an 'opened' event if finished.
153	*
154	* @api
155	* @returns {boolean}
156	*/
157	open() {
158	this.index.open();	688✔
159
160	this.forEachSecondaryIndex(index => index.open());	688✔
161
162	this.emit('opened');	688✔
163	return true;	688✔
164	}
165
166	/**
167	* Close the storage and frees up all resources.
168	* Will emit a 'closed' event when finished.
169	*
170	* @api
171	* @returns void
172	*/
173	close() {
174	this.index.close();	1,196✔
175	this.forEachSecondaryIndex(index => index.close());	1,196✔
176	for (let index of Object.values(this.readonlyIndexes)) {	1,196✔
177	index.close();	44✔
178	}
179	this.forEachPartition(partition => partition.close());	1,208✔
180	this.emit('closed');	1,196✔
181	}
182
183	/**
184	* Get a partition either by name or by id.
185	* If a partition with the given name does not exist, a new one will be created.
186	* If a partition with the given id does not exist, an error is thrown.
187	*
188	* @protected
189	* @param {string\|number} partitionIdentifier The partition name or the partition Id
190	* @returns {ReadablePartition}
191	* @throws {Error} If an id is given and no such partition exists.
192	*/
193	getPartition(partitionIdentifier) {
194	assert(partitionIdentifier in this.partitions, `Partition #${partitionIdentifier} does not exist.`);	3,356✔
195
196	this.partitions[partitionIdentifier].open();	3,356✔
197	return this.partitions[partitionIdentifier];	3,356✔
198	}
199
200	/**
201	* @protected
202	* @param {number} partitionId The partition to read from.
203	* @param {number} position The file position to read from.
204	* @param {number} [size] The expected byte size of the document at the given position.
205	* @returns {object} The document stored at the given position.
206	* @throws {Error} if the document at the given position can not be deserialized.
207	*/
208	readFrom(partitionId, position, size) {
209	const partition = this.getPartition(partitionId);	3,316✔
210	const data = partition.readFrom(position, size);	3,316✔
211	return this.serializer.deserialize(data);	3,316✔
212	}
213
214	/**
215	* Read a single document from the given position, in the full index or in the provided index.
216	*
217	* @api
218	* @param {number} number The 1-based document number (inside the given index) to read.
219	* @param {ReadableIndex} [index] The index to use for finding the document position.
220	* @returns {object} The document at the given position inside the index.
221	*/
222	read(number, index) {
223	index = index \|\| this.index;	168✔
224
225	if (!index.isOpen()) {	168✔
226	index.open();	4✔
227	}
228
229	const entry = index.get(number);	168✔
230	if (entry === false) {	168✔
231	return false;	4✔
232	}
233
234	return this.readFrom(entry.partition, entry.position, entry.size);	164✔
235	}
236
237	/**
238	* Read a range of documents from the given position range, in the provided index or across all partitions.
239	* When no index is given, iterates all partitions directly and returns documents ordered by their
240	* sequenceNumber, allowing reconstruction of insertion order without a global index.
241	* Returns a generator in order to reduce memory usage and be able to read lots of documents with little latency.
242	*
243	* @api
244	* @param {number} from The 1-based document number (inclusive) to start reading from.
245	* @param {number} [until] The 1-based document number (inclusive) to read until. Defaults to index.length.
246	* @param {ReadableIndex} [index] The index to use for finding the documents in the range. If not given, iterates all partitions ordered by sequenceNumber.
247	* @returns {Generator<object>} A generator that will read each document in the range one by one.
248	*/
249	*readRange(from, until = -1, index = null) {	80✔
250	const lengthSource = index \|\| this.index;	472✔
251	if (!lengthSource.isOpen()) {	472✔
252	lengthSource.open();	4✔
253	}
254
255	const readFrom = wrapAndCheck(from, lengthSource.length);	472✔
256	const readUntil = wrapAndCheck(until, lengthSource.length);	472✔
257	assert(readFrom > 0 && readUntil > 0, `Range scan error for range ${from} - ${until}.`);	472✔
258
259	if (readFrom > readUntil) {	456✔
260	const batchSize = 10;	44✔
261	let batchUntil = readFrom;	44✔
262	while (batchUntil > readUntil) {	44✔
263	const batchFrom = Math.max(readUntil, batchUntil - batchSize);	60✔
264	yield* reverse(this.iterateRange(batchFrom, batchUntil, index));	60✔
265	batchUntil = batchFrom - 1;	60✔
266	}
267	return undefined;	44✔
268	}
269
270	yield* this.iterateRange(readFrom, readUntil, index);	412✔
271	}
272
273	/**
274	* Iterate all documents in this storage in range from to until.
275	* If an index is provided, uses it to look up document positions; otherwise iterates all partitions
276	* directly and merges them in sequenceNumber order.
277	* @private
278	* @param {number} from
279	* @param {number} until
280	* @param {ReadableIndex\|null} index
281	* @returns {Generator<object>}
282	*/
283	*iterateRange(from, until, index) {
284	if (index !== null) {	472✔
285	const entries = index.range(from, until);	428✔
286	for (let entry of entries) {	428✔
287	const document = this.readFrom(entry.partition, entry.position, entry.size);	1,412✔
288	yield document;	1,412✔
289	}
290	return;	420✔
291	}
292
293	// No index: iterate all partitions and merge documents by sequenceNumber.
294	// Document header sequenceNumber is 0-based; from/until are 1-based index positions.
295	yield* this.iteratePartitionsBySequenceNumber(from - 1, until - 1);	44✔
296	}
297
298	/**
299	* Iterate documents across all partitions in sequenceNumber order using a k-way merge.
300	* SequenceNumbers stored in document headers are 0-based.
301	* @private
302	* @param {number} fromSeq The 0-based sequenceNumber to start from (inclusive).
303	* @param {number} untilSeq The 0-based sequenceNumber to read until (inclusive).
304	* @returns {Generator<object>}
305	*/
306	*iteratePartitionsBySequenceNumber(fromSeq, untilSeq) {
307	const iterators = [];	44✔
308
309	for (const partition of Object.values(this.partitions)) {	44✔
310	if (!partition.isOpen()) {	76✔
311	partition.open();	60✔
312	}
313	const gen = partition.readAllWithHeaders();	76✔
314
315	// Advance to the first document with sequenceNumber >= fromSeq
316	let result = gen.next();	76✔
317	while (!result.done && result.value.sequenceNumber < fromSeq) {	76✔
318	result = gen.next();	80✔
319	}
320
321	if (!result.done && result.value.sequenceNumber <= untilSeq) {	76✔
322	iterators.push({ gen, current: result.value });	72✔
323	}
324	}
325
326	// K-way merge: at each step, yield the document with the smallest sequenceNumber
327	while (iterators.length > 0) {	44✔
328	let minIdx = 0;	316✔
329	for (let i = 1; i < iterators.length; i++) {	316✔
330	if (iterators[i].current.sequenceNumber < iterators[minIdx].current.sequenceNumber) {	164✔
331	minIdx = i;	72✔
332	}
333	}
334
335	yield this.serializer.deserialize(iterators[minIdx].current.data);	316✔
336
337	const next = iterators[minIdx].gen.next();	316✔
338	if (!next.done && next.value.sequenceNumber <= untilSeq) {	316✔
339	iterators[minIdx].current = next.value;	244✔
340	} else {
341	iterators.splice(minIdx, 1);	72✔
342	}
343	}
344	}
345
346	/**
347	* Open an existing readonly index for reading, without registering it in the secondary indexes write path.
348	* Use this for indexes whose files carry a status marker (e.g. `stream-foo.closed.index`).
349	*
350	* @api
351	* @param {string} name The readonly index name (e.g. 'stream-foo.closed').
352	* @returns {ReadableIndex}
353	* @throws {Error} if the readonly index does not exist.
354	*/
355	openReadonlyIndex(name) {
356	if (name in this.readonlyIndexes) {	44!
UNCOV 357	return this.readonlyIndexes[name];	×
358	}
359	const indexName = this.storageFile + '.' + name + '.index';	44✔
360	assert(fs.existsSync(path.join(this.indexDirectory, indexName)), `Index "${name}" does not exist.`);	44✔
361	const { index } = this.createIndex(indexName, Object.assign({}, this.indexOptions));	44✔
362	index.open();	44✔
363	this.readonlyIndexes[name] = index;	44✔
364	return index;	44✔
365	}
366
367	/**
368	* Open an existing index.
369	*
370	* @api
371	* @param {string} name The index name.
372	* @param {Matcher} [matcher] The matcher object or function that the index needs to have been defined with. If not given it will not be validated.
373	* @returns {ReadableIndex}
374	* @throws {Error} if the index with that name does not exist.
375	* @throws {Error} if the HMAC for the matcher does not match.
376	*/
377	openIndex(name, matcher) {
378	if (name === '_all') {	588✔
379	return this.index;	8✔
380	}
381	if (name in this.secondaryIndexes) {	580✔
382	return this.secondaryIndexes[name].index;	520✔
383	}
384
385	const indexName = this.storageFile + '.' + name + '.index';	60✔
386	assert(fs.existsSync(path.join(this.indexDirectory, indexName)), `Index "${name}" does not exist.`);	60✔
387
388	const metadata = buildMetadataForMatcher(matcher, this.hmac);	56✔
389	let { index } = this.secondaryIndexes[name] = this.createIndex(indexName, Object.assign({}, this.indexOptions, { metadata }));	56✔
390
391	index.open();	44✔
392	return index;	44✔
393	}
394
395	/**
396	* Helper method to iterate over all documents.
397	*
398	* @protected
399	* @param {function(object, EntryInterface)} iterationHandler
400	*/
401	forEachDocument(iterationHandler) {
402	/* istanbul ignore if */
403	if (typeof iterationHandler !== 'function') {	724✔
404	return;
405	}
406
407	const entries = this.index.all();	724✔
408
409	for (let entry of entries) {	724✔
410	const document = this.readFrom(entry.partition, entry.position, entry.size);	1,728✔
411	iterationHandler(document, entry);	1,728✔
412	}
413	}
414
415	/**
416	* Helper method to iterate over all secondary indexes.
417	*
418	* @protected
419	* @param {function(ReadableIndex, string)} iterationHandler
420	* @param {object} [matchDocument] If supplied, only indexes the document matches on will be iterated.
421	*/
422	forEachSecondaryIndex(iterationHandler, matchDocument) {
423	/* istanbul ignore if */
424	if (typeof iterationHandler !== 'function') {	4,332✔
425	return;
426	}
427
428	for (let indexName of Object.keys(this.secondaryIndexes)) {	4,332✔
429	if (!matchDocument \|\| matches(matchDocument, this.secondaryIndexes[indexName].matcher)) {	4,456✔
430	iterationHandler(this.secondaryIndexes[indexName].index, indexName);	2,220✔
431	}
432	}
433	}
434
435	/**
436	* Helper method to iterate over all partitions.
437	*
438	* @protected
439	* @param {function(ReadablePartition)} iterationHandler
440	*/
441	forEachPartition(iterationHandler) {
442	/* istanbul ignore if */
443	if (typeof iterationHandler !== 'function') {	1,264✔
444	return;
445	}
446
447	for (let partition of Object.keys(this.partitions)) {	1,264✔
448	iterationHandler(this.partitions[partition]);	1,268✔
449	}
450	}
451
452	}
453
454	module.exports = ReadableStorage;	4✔
455	module.exports.matches = matches;	4✔

albe / node-event-storage / 23376498872

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