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/*
MIT License http://www.opensource.org/licenses/mit-license.php
*/
"use strict";
const { constants } = require("buffer");
const { pipeline } = require("stream");
const {
createBrotliCompress,
createBrotliDecompress,
createGzip,
createGunzip,
constants: zConstants
} = require("zlib");
const createHash = require("../util/createHash");
const { dirname, join, mkdirp } = require("../util/fs");
const memoize = require("../util/memoize");
const SerializerMiddleware = require("./SerializerMiddleware");
/** @typedef {typeof import("../util/Hash")} Hash */
/** @typedef {import("../util/fs").IntermediateFileSystem} IntermediateFileSystem */
/** @typedef {import("./types").BufferSerializableType} BufferSerializableType */
/*
Format:
File -> Header Section*
Version -> u32
AmountOfSections -> u32
SectionSize -> i32 (if less than zero represents lazy value)
Header -> Version AmountOfSections SectionSize*
Buffer -> n bytes
Section -> Buffer
*/
// "wpc" + 1 in little-endian
const VERSION = 0x01637077;
const WRITE_LIMIT_TOTAL = 0x7fff0000;
const WRITE_LIMIT_CHUNK = 511 * 1024 * 1024;
/**
* @param {Buffer[]} buffers buffers
* @param {string | Hash} hashFunction hash function to use
* @returns {string} hash
*/
const hashForName = (buffers, hashFunction) => {
const hash = createHash(hashFunction);
for (const buf of buffers) hash.update(buf);
return /** @type {string} */ (hash.digest("hex"));
};
const COMPRESSION_CHUNK_SIZE = 100 * 1024 * 1024;
const DECOMPRESSION_CHUNK_SIZE = 100 * 1024 * 1024;
const writeUInt64LE = Buffer.prototype.writeBigUInt64LE
? (buf, value, offset) => {
buf.writeBigUInt64LE(BigInt(value), offset);
}
: (buf, value, offset) => {
const low = value % 0x100000000;
const high = (value - low) / 0x100000000;
buf.writeUInt32LE(low, offset);
buf.writeUInt32LE(high, offset + 4);
};
const readUInt64LE = Buffer.prototype.readBigUInt64LE
? (buf, offset) => {
return Number(buf.readBigUInt64LE(offset));
}
: (buf, offset) => {
const low = buf.readUInt32LE(offset);
const high = buf.readUInt32LE(offset + 4);
return high * 0x100000000 + low;
};
/**
* @typedef {Object} SerializeResult
* @property {string | false} name
* @property {number} size
* @property {Promise=} backgroundJob
*/
/**
* @param {FileMiddleware} middleware this
* @param {BufferSerializableType[] | Promise<BufferSerializableType[]>} data data to be serialized
* @param {string | boolean} name file base name
* @param {function(string | false, Buffer[], number): Promise<void>} writeFile writes a file
* @param {string | Hash} hashFunction hash function to use
* @returns {Promise<SerializeResult>} resulting file pointer and promise
*/
const serialize = async (
middleware,
data,
name,
writeFile,
hashFunction = "md4"
) => {
/** @type {(Buffer[] | Buffer | SerializeResult | Promise<SerializeResult>)[]} */
const processedData = [];
/** @type {WeakMap<SerializeResult, function(): any | Promise<any>>} */
const resultToLazy = new WeakMap();
/** @type {Buffer[]} */
let lastBuffers = undefined;
for (const item of await data) {
if (typeof item === "function") {
if (!SerializerMiddleware.isLazy(item))
throw new Error("Unexpected function");
if (!SerializerMiddleware.isLazy(item, middleware)) {
throw new Error(
"Unexpected lazy value with non-this target (can't pass through lazy values)"
);
}
lastBuffers = undefined;
const serializedInfo = SerializerMiddleware.getLazySerializedValue(item);
if (serializedInfo) {
if (typeof serializedInfo === "function") {
throw new Error(
"Unexpected lazy value with non-this target (can't pass through lazy values)"
);
} else {
processedData.push(serializedInfo);
}
} else {
const content = item();
if (content) {
const options = SerializerMiddleware.getLazyOptions(item);
processedData.push(
serialize(
middleware,
content,
(options && options.name) || true,
writeFile,
hashFunction
).then(result => {
/** @type {any} */ (item).options.size = result.size;
resultToLazy.set(result, item);
return result;
})
);
} else {
throw new Error(
"Unexpected falsy value returned by lazy value function"
);
}
}
} else if (item) {
if (lastBuffers) {
lastBuffers.push(item);
} else {
lastBuffers = [item];
processedData.push(lastBuffers);
}
} else {
throw new Error("Unexpected falsy value in items array");
}
}
/** @type {Promise<any>[]} */
const backgroundJobs = [];
const resolvedData = (
await Promise.all(
/** @type {Promise<Buffer[] | Buffer | SerializeResult>[]} */ (
processedData
)
)
).map(item => {
if (Array.isArray(item) || Buffer.isBuffer(item)) return item;
backgroundJobs.push(item.backgroundJob);
// create pointer buffer from size and name
const name = /** @type {string} */ (item.name);
const nameBuffer = Buffer.from(name);
const buf = Buffer.allocUnsafe(8 + nameBuffer.length);
writeUInt64LE(buf, item.size, 0);
nameBuffer.copy(buf, 8, 0);
const lazy = resultToLazy.get(item);
SerializerMiddleware.setLazySerializedValue(lazy, buf);
return buf;
});
const lengths = [];
for (const item of resolvedData) {
if (Array.isArray(item)) {
let l = 0;
for (const b of item) l += b.length;
while (l > 0x7fffffff) {
lengths.push(0x7fffffff);
l -= 0x7fffffff;
}
lengths.push(l);
} else if (item) {
lengths.push(-item.length);
} else {
throw new Error("Unexpected falsy value in resolved data " + item);
}
}
const header = Buffer.allocUnsafe(8 + lengths.length * 4);
header.writeUInt32LE(VERSION, 0);
header.writeUInt32LE(lengths.length, 4);
for (let i = 0; i < lengths.length; i++) {
header.writeInt32LE(lengths[i], 8 + i * 4);
}
const buf = [header];
for (const item of resolvedData) {
if (Array.isArray(item)) {
for (const b of item) buf.push(b);
} else if (item) {
buf.push(item);
}
}
if (name === true) {
name = hashForName(buf, hashFunction);
}
let size = 0;
for (const b of buf) size += b.length;
backgroundJobs.push(writeFile(name, buf, size));
return {
size,
name,
backgroundJob:
backgroundJobs.length === 1
? backgroundJobs[0]
: Promise.all(backgroundJobs)
};
};
/**
* @param {FileMiddleware} middleware this
* @param {string | false} name filename
* @param {function(string | false): Promise<Buffer[]>} readFile read content of a file
* @returns {Promise<BufferSerializableType[]>} deserialized data
*/
const deserialize = async (middleware, name, readFile) => {
const contents = await readFile(name);
if (contents.length === 0) throw new Error("Empty file " + name);
let contentsIndex = 0;
let contentItem = contents[0];
let contentItemLength = contentItem.length;
let contentPosition = 0;
if (contentItemLength === 0) throw new Error("Empty file " + name);
const nextContent = () => {
contentsIndex++;
contentItem = contents[contentsIndex];
contentItemLength = contentItem.length;
contentPosition = 0;
};
const ensureData = n => {
if (contentPosition === contentItemLength) {
nextContent();
}
while (contentItemLength - contentPosition < n) {
const remaining = contentItem.slice(contentPosition);
let lengthFromNext = n - remaining.length;
const buffers = [remaining];
for (let i = contentsIndex + 1; i < contents.length; i++) {
const l = contents[i].length;
if (l > lengthFromNext) {
buffers.push(contents[i].slice(0, lengthFromNext));
contents[i] = contents[i].slice(lengthFromNext);
lengthFromNext = 0;
break;
} else {
buffers.push(contents[i]);
contentsIndex = i;
lengthFromNext -= l;
}
}
if (lengthFromNext > 0) throw new Error("Unexpected end of data");
contentItem = Buffer.concat(buffers, n);
contentItemLength = n;
contentPosition = 0;
}
};
const readUInt32LE = () => {
ensureData(4);
const value = contentItem.readUInt32LE(contentPosition);
contentPosition += 4;
return value;
};
const readInt32LE = () => {
ensureData(4);
const value = contentItem.readInt32LE(contentPosition);
contentPosition += 4;
return value;
};
const readSlice = l => {
ensureData(l);
if (contentPosition === 0 && contentItemLength === l) {
const result = contentItem;
if (contentsIndex + 1 < contents.length) {
nextContent();
} else {
contentPosition = l;
}
return result;
}
const result = contentItem.slice(contentPosition, contentPosition + l);
contentPosition += l;
// we clone the buffer here to allow the original content to be garbage collected
return l * 2 < contentItem.buffer.byteLength ? Buffer.from(result) : result;
};
const version = readUInt32LE();
if (version !== VERSION) {
throw new Error("Invalid file version");
}
const sectionCount = readUInt32LE();
const lengths = [];
let lastLengthPositive = false;
for (let i = 0; i < sectionCount; i++) {
const value = readInt32LE();
const valuePositive = value >= 0;
if (lastLengthPositive && valuePositive) {
lengths[lengths.length - 1] += value;
} else {
lengths.push(value);
lastLengthPositive = valuePositive;
}
}
const result = [];
for (let length of lengths) {
if (length < 0) {
const slice = readSlice(-length);
const size = Number(readUInt64LE(slice, 0));
const nameBuffer = slice.slice(8);
const name = nameBuffer.toString();
result.push(
SerializerMiddleware.createLazy(
memoize(() => deserialize(middleware, name, readFile)),
middleware,
{
name,
size
},
slice
)
);
} else {
if (contentPosition === contentItemLength) {
nextContent();
} else if (contentPosition !== 0) {
if (length <= contentItemLength - contentPosition) {
result.push(
Buffer.from(
contentItem.buffer,
contentItem.byteOffset + contentPosition,
length
)
);
contentPosition += length;
length = 0;
} else {
const l = contentItemLength - contentPosition;
result.push(
Buffer.from(
contentItem.buffer,
contentItem.byteOffset + contentPosition,
l
)
);
length -= l;
contentPosition = contentItemLength;
}
} else {
if (length >= contentItemLength) {
result.push(contentItem);
length -= contentItemLength;
contentPosition = contentItemLength;
} else {
result.push(
Buffer.from(contentItem.buffer, contentItem.byteOffset, length)
);
contentPosition += length;
length = 0;
}
}
while (length > 0) {
nextContent();
if (length >= contentItemLength) {
result.push(contentItem);
length -= contentItemLength;
contentPosition = contentItemLength;
} else {
result.push(
Buffer.from(contentItem.buffer, contentItem.byteOffset, length)
);
contentPosition += length;
length = 0;
}
}
}
}
return result;
};
/**
* @typedef {BufferSerializableType[]} DeserializedType
* @typedef {true} SerializedType
* @extends {SerializerMiddleware<DeserializedType, SerializedType>}
*/
class FileMiddleware extends SerializerMiddleware {
/**
* @param {IntermediateFileSystem} fs filesystem
* @param {string | Hash} hashFunction hash function to use
*/
constructor(fs, hashFunction = "md4") {
super();
this.fs = fs;
this._hashFunction = hashFunction;
}
/**
* @param {DeserializedType} data data
* @param {Object} context context object
* @returns {SerializedType|Promise<SerializedType>} serialized data
*/
serialize(data, context) {
const { filename, extension = "" } = context;
return new Promise((resolve, reject) => {
mkdirp(this.fs, dirname(this.fs, filename), err => {
if (err) return reject(err);
// It's important that we don't touch existing files during serialization
// because serialize may read existing files (when deserializing)
const allWrittenFiles = new Set();
const writeFile = async (name, content, size) => {
const file = name
? join(this.fs, filename, `../${name}${extension}`)
: filename;
await new Promise((resolve, reject) => {
let stream = this.fs.createWriteStream(file + "_");
let compression;
if (file.endsWith(".gz")) {
compression = createGzip({
chunkSize: COMPRESSION_CHUNK_SIZE,
level: zConstants.Z_BEST_SPEED
});
} else if (file.endsWith(".br")) {
compression = createBrotliCompress({
chunkSize: COMPRESSION_CHUNK_SIZE,
params: {
[zConstants.BROTLI_PARAM_MODE]: zConstants.BROTLI_MODE_TEXT,
[zConstants.BROTLI_PARAM_QUALITY]: 2,
[zConstants.BROTLI_PARAM_DISABLE_LITERAL_CONTEXT_MODELING]: true,
[zConstants.BROTLI_PARAM_SIZE_HINT]: size
}
});
}
if (compression) {
pipeline(compression, stream, reject);
stream = compression;
stream.on("finish", () => resolve());
} else {
stream.on("error", err => reject(err));
stream.on("finish", () => resolve());
}
// split into chunks for WRITE_LIMIT_CHUNK size
const chunks = [];
for (const b of content) {
if (b.length < WRITE_LIMIT_CHUNK) {
chunks.push(b);
} else {
for (let i = 0; i < b.length; i += WRITE_LIMIT_CHUNK) {
chunks.push(b.slice(i, i + WRITE_LIMIT_CHUNK));
}
}
}
const len = chunks.length;
let i = 0;
const batchWrite = err => {
// will be handled in "on" error handler
if (err) return;
if (i === len) {
stream.end();
return;
}
// queue up a batch of chunks up to the write limit
// end is exclusive
let end = i;
let sum = chunks[end++].length;
while (end < len) {
sum += chunks[end].length;
if (sum > WRITE_LIMIT_TOTAL) break;
end++;
}
while (i < end - 1) {
stream.write(chunks[i++]);
}
stream.write(chunks[i++], batchWrite);
};
batchWrite();
});
if (name) allWrittenFiles.add(file);
};
resolve(
serialize(this, data, false, writeFile, this._hashFunction).then(
async ({ backgroundJob }) => {
await backgroundJob;
// Rename the index file to disallow access during inconsistent file state
await new Promise(resolve =>
this.fs.rename(filename, filename + ".old", err => {
resolve();
})
);
// update all written files
await Promise.all(
Array.from(
allWrittenFiles,
file =>
new Promise((resolve, reject) => {
this.fs.rename(file + "_", file, err => {
if (err) return reject(err);
resolve();
});
})
)
);
// As final step automatically update the index file to have a consistent pack again
await new Promise(resolve => {
this.fs.rename(filename + "_", filename, err => {
if (err) return reject(err);
resolve();
});
});
return /** @type {true} */ (true);
}
)
);
});
});
}
/**
* @param {SerializedType} data data
* @param {Object} context context object
* @returns {DeserializedType|Promise<DeserializedType>} deserialized data
*/
deserialize(data, context) {
const { filename, extension = "" } = context;
const readFile = name =>
new Promise((resolve, reject) => {
const file = name
? join(this.fs, filename, `../${name}${extension}`)
: filename;
this.fs.stat(file, (err, stats) => {
if (err) {
reject(err);
return;
}
let remaining = /** @type {number} */ (stats.size);
let currentBuffer;
let currentBufferUsed;
const buf = [];
let decompression;
if (file.endsWith(".gz")) {
decompression = createGunzip({
chunkSize: DECOMPRESSION_CHUNK_SIZE
});
} else if (file.endsWith(".br")) {
decompression = createBrotliDecompress({
chunkSize: DECOMPRESSION_CHUNK_SIZE
});
}
if (decompression) {
let newResolve, newReject;
resolve(
Promise.all([
new Promise((rs, rj) => {
newResolve = rs;
newReject = rj;
}),
new Promise((resolve, reject) => {
decompression.on("data", chunk => buf.push(chunk));
decompression.on("end", () => resolve());
decompression.on("error", err => reject(err));
})
]).then(() => buf)
);
resolve = newResolve;
reject = newReject;
}
this.fs.open(file, "r", (err, fd) => {
if (err) {
reject(err);
return;
}
const read = () => {
if (currentBuffer === undefined) {
currentBuffer = Buffer.allocUnsafeSlow(
Math.min(
constants.MAX_LENGTH,
remaining,
decompression ? DECOMPRESSION_CHUNK_SIZE : Infinity
)
);
currentBufferUsed = 0;
}
let readBuffer = currentBuffer;
let readOffset = currentBufferUsed;
let readLength = currentBuffer.length - currentBufferUsed;
// values passed to fs.read must be valid int32 values
if (readOffset > 0x7fffffff) {
readBuffer = currentBuffer.slice(readOffset);
readOffset = 0;
}
if (readLength > 0x7fffffff) {
readLength = 0x7fffffff;
}
this.fs.read(
fd,
readBuffer,
readOffset,
readLength,
null,
(err, bytesRead) => {
if (err) {
this.fs.close(fd, () => {
reject(err);
});
return;
}
currentBufferUsed += bytesRead;
remaining -= bytesRead;
if (currentBufferUsed === currentBuffer.length) {
if (decompression) {
decompression.write(currentBuffer);
} else {
buf.push(currentBuffer);
}
currentBuffer = undefined;
if (remaining === 0) {
if (decompression) {
decompression.end();
}
this.fs.close(fd, err => {
if (err) {
reject(err);
return;
}
resolve(buf);
});
return;
}
}
read();
}
);
};
read();
});
});
});
return deserialize(this, false, readFile);
}
}
module.exports = FileMiddleware;