graphql-upload-ts/dist/fs-capacitor.js

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.WriteStream = exports.ReadStream = exports.ReadAfterReleasedError = exports.ReadAfterDestroyedError = void 0;
const crypto_1 = require("crypto");
const fs_1 = require("fs");
const os_1 = require("os");
const path_1 = require("path");
const stream_1 = require("stream");
const events_1 = require("events");
class ReadAfterDestroyedError extends Error {
}
exports.ReadAfterDestroyedError = ReadAfterDestroyedError;
class ReadAfterReleasedError extends Error {
}
exports.ReadAfterReleasedError = ReadAfterReleasedError;
// Use a “proxy” event emitter configured to have an infinite maximum number of
// listeners to prevent Node.js max listeners exceeded warnings if many
// `fs-capacitor` `ReadStream` instances are created at the same time. See:
// https://github.com/mike-marcacci/fs-capacitor/issues/30
const processExitProxy = new events_1.EventEmitter();
processExitProxy.setMaxListeners(Infinity);
process.once('exit', () => processExitProxy.emit('exit'));
class ReadStream extends stream_1.Readable {
    constructor(writeStream, options) {
        super({
            highWaterMark: options === null || options === void 0 ? void 0 : options.highWaterMark,
            encoding: options === null || options === void 0 ? void 0 : options.encoding,
            autoDestroy: true,
        });
        this._pos = 0;
        this._writeStream = writeStream;
    }
    _read(n) {
        if (this.destroyed)
            return;
        if (typeof this._writeStream['_fd'] !== 'number') {
            this._writeStream.once('ready', () => this._read(n));
            return;
        }
        // Using `allocUnsafe` here is OK because we return a slice the length of
        // `bytesRead`, and discard the rest. This prevents node from having to zero
        // out the entire allocation first.
        const buf = Buffer.allocUnsafe(n);
        (0, fs_1.read)(this._writeStream['_fd'], buf, 0, n, this._pos, (error, bytesRead) => {
            if (error)
                this.destroy(error);
            // Push any read bytes into the local stream buffer.
            if (bytesRead) {
                this._pos += bytesRead;
                this.push(buf.slice(0, bytesRead));
                return;
            }
            // If there were no more bytes to read and the write stream is finished,
            // then this stream has reached the end.
            if (this._writeStream._writableState.finished) {
                // Check if we have consumed the whole file up to where
                // the write stream has written before ending the stream
                if (this._pos < this._writeStream._pos)
                    this._read(n);
                else
                    this.push(null);
                return;
            }
            // Otherwise, wait for the write stream to add more data or finish.
            const retry = () => {
                this._writeStream.off('finish', retry);
                this._writeStream.off('write', retry);
                this._read(n);
            };
            this._writeStream.on('finish', retry);
            this._writeStream.on('write', retry);
        });
    }
}
exports.ReadStream = ReadStream;
class WriteStream extends stream_1.Writable {
    constructor(options) {
        super({
            highWaterMark: options === null || options === void 0 ? void 0 : options.highWaterMark,
            defaultEncoding: options === null || options === void 0 ? void 0 : options.defaultEncoding,
            autoDestroy: false,
        });
        this._fd = null;
        this._path = null;
        this._pos = 0;
        this._readStreams = new Set();
        this._released = false;
        this._cleanup = (callback) => {
            const fd = this._fd;
            const path = this._path;
            if (typeof fd !== 'number' || typeof path !== 'string') {
                callback(null);
                return;
            }
            // Close the file descriptor.
            (0, fs_1.close)(fd, (closeError) => {
                // An error here probably means the fd was already closed, but we can
                // still try to unlink the file.
                (0, fs_1.unlink)(path, (unlinkError) => {
                    // If we are unable to unlink the file, the operating system will
                    // clean up on next restart, since we use store thes in `os.tmpdir()`
                    this._fd = null;
                    // We avoid removing this until now in case an exit occurs while
                    // asyncronously cleaning up.
                    processExitProxy.off('exit', this._cleanupSync);
                    callback(unlinkError !== null && unlinkError !== void 0 ? unlinkError : closeError);
                });
            });
        };
        this._cleanupSync = () => {
            processExitProxy.off('exit', this._cleanupSync);
            if (typeof this._fd === 'number')
                try {
                    (0, fs_1.closeSync)(this._fd);
                }
                catch (error) {
                    // An error here probably means the fd was already closed, but we can
                    // still try to unlink the file.
                }
            try {
                if (this._path !== null) {
                    (0, fs_1.unlinkSync)(this._path);
                }
            }
            catch (error) {
                // If we are unable to unlink the file, the operating system will clean
                // up on next restart, since we use store thes in `os.tmpdir()`
            }
        };
        // Generate a random filename.
        (0, crypto_1.randomBytes)(16, (error, buffer) => {
            var _a;
            if (error) {
                this.destroy(error);
                return;
            }
            this._path = (0, path_1.join)(((_a = options === null || options === void 0 ? void 0 : options.tmpdir) !== null && _a !== void 0 ? _a : os_1.tmpdir)(), `capacitor-${buffer.toString('hex')}.tmp`);
            // Create a file in the OS's temporary files directory.
            (0, fs_1.open)(this._path, 'wx+', 0o600, (error, fd) => {
                if (error) {
                    this.destroy(error);
                    return;
                }
                // Cleanup when the process exits or is killed.
                processExitProxy.once('exit', this._cleanupSync);
                this._fd = fd;
                this.emit('ready');
            });
        });
    }
    _final(callback) {
        if (typeof this._fd !== 'number') {
            this.once('ready', () => this._final(callback));
            return;
        }
        callback();
    }
    _write(chunk, encoding, callback) {
        if (typeof this._fd !== 'number') {
            this.once('ready', () => this._write(chunk, encoding, callback));
            return;
        }
        (0, fs_1.write)(this._fd, chunk, 0, chunk.length, this._pos, (error) => {
            if (error) {
                callback(error);
                return;
            }
            // It's safe to increment `this._pos` after flushing to the filesystem
            // because node streams ensure that only one `_write()` is active at a
            // time. If this assumption is broken, the behavior of this library is
            // undefined, regardless of where this is incremented. Relocating this
            // to increment syncronously would result in correct file contents, but
            // the out-of-order writes would still open the potential for read streams
            // to scan positions that have not yet been written.
            this._pos += chunk.length;
            this.emit('write');
            callback();
        });
    }
    release() {
        this._released = true;
        if (this._readStreams.size === 0)
            this.destroy();
    }
    _destroy(error, callback) {
        // Destroy all attached read streams.
        for (const readStream of this._readStreams) {
            readStream.destroy(error || undefined);
        }
        // This capacitor is fully initialized.
        if (typeof this._fd === 'number' && typeof this._path === 'string') {
            this._cleanup((cleanupError) => callback(cleanupError !== null && cleanupError !== void 0 ? cleanupError : error));
            return;
        }
        // This capacitor has not yet finished initialization; if initialization
        // does complete, immediately clean up after.
        this.once('ready', () => {
            this._cleanup((cleanupError) => {
                if (cleanupError) {
                    this.emit('error', cleanupError);
                }
            });
        });
        callback(error);
    }
    createReadStream(options) {
        if (this.destroyed)
            throw new ReadAfterDestroyedError('A ReadStream cannot be created from a destroyed WriteStream.');
        if (this._released)
            throw new ReadAfterReleasedError('A ReadStream cannot be created from a released WriteStream.');
        const readStream = new ReadStream(this, options);
        this._readStreams.add(readStream);
        readStream.once('close', () => {
            this._readStreams.delete(readStream);
            if (this._released && this._readStreams.size === 0) {
                this.destroy();
            }
        });
        return readStream;
    }
}
exports.WriteStream = WriteStream;
exports.default = {
    WriteStream,
    ReadStream,
    ReadAfterDestroyedError,
    ReadAfterReleasedError,
};
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