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Mini Shell
Mini Shell
'use strict';
const {
Array,
FunctionPrototypeBind,
MathMin,
ObjectDefineProperty,
ObjectSetPrototypeOf,
PromisePrototypeThen,
ReflectApply,
Symbol,
} = primordials;
const {
ERR_INVALID_ARG_TYPE,
ERR_METHOD_NOT_IMPLEMENTED,
ERR_OUT_OF_RANGE,
ERR_STREAM_DESTROYED,
ERR_SYSTEM_ERROR,
} = require('internal/errors').codes;
const {
deprecate,
kEmptyObject,
} = require('internal/util');
const {
validateBoolean,
validateFunction,
validateInteger,
} = require('internal/validators');
const { errorOrDestroy } = require('internal/streams/destroy');
const fs = require('fs');
const { kRef, kUnref, FileHandle } = require('internal/fs/promises');
const { Buffer } = require('buffer');
const {
copyObject,
getOptions,
getValidatedFd,
validatePath,
} = require('internal/fs/utils');
const { Readable, Writable, finished } = require('stream');
const { toPathIfFileURL } = require('internal/url');
const kIoDone = Symbol('kIoDone');
const kIsPerformingIO = Symbol('kIsPerformingIO');
const kFs = Symbol('kFs');
const kHandle = Symbol('kHandle');
function _construct(callback) {
const stream = this;
if (typeof stream.fd === 'number') {
callback();
return;
}
if (stream.open !== openWriteFs && stream.open !== openReadFs) {
// Backwards compat for monkey patching open().
const orgEmit = stream.emit;
stream.emit = function(...args) {
if (args[0] === 'open') {
this.emit = orgEmit;
callback();
ReflectApply(orgEmit, this, args);
} else if (args[0] === 'error') {
this.emit = orgEmit;
callback(args[1]);
} else {
ReflectApply(orgEmit, this, args);
}
};
stream.open();
} else {
stream[kFs].open(stream.path, stream.flags, stream.mode, (er, fd) => {
if (er) {
callback(er);
} else {
stream.fd = fd;
callback();
stream.emit('open', stream.fd);
stream.emit('ready');
}
});
}
}
// This generates an fs operations structure for a FileHandle
const FileHandleOperations = (handle) => {
return {
open: (path, flags, mode, cb) => {
throw new ERR_METHOD_NOT_IMPLEMENTED('open()');
},
close: (fd, cb) => {
handle[kUnref]();
PromisePrototypeThen(handle.close(),
() => cb(), cb);
},
fsync: (fd, cb) => {
PromisePrototypeThen(handle.sync(), () => cb(), cb);
},
read: (fd, buf, offset, length, pos, cb) => {
PromisePrototypeThen(handle.read(buf, offset, length, pos),
(r) => cb(null, r.bytesRead, r.buffer),
(err) => cb(err, 0, buf));
},
write: (fd, buf, offset, length, pos, cb) => {
PromisePrototypeThen(handle.write(buf, offset, length, pos),
(r) => cb(null, r.bytesWritten, r.buffer),
(err) => cb(err, 0, buf));
},
writev: (fd, buffers, pos, cb) => {
PromisePrototypeThen(handle.writev(buffers, pos),
(r) => cb(null, r.bytesWritten, r.buffers),
(err) => cb(err, 0, buffers));
},
};
};
function close(stream, err, cb) {
if (!stream.fd) {
cb(err);
} else if (stream.flush) {
stream[kFs].fsync(stream.fd, (flushErr) => {
_close(stream, err || flushErr, cb);
});
} else {
_close(stream, err, cb);
}
}
function _close(stream, err, cb) {
stream[kFs].close(stream.fd, (er) => {
cb(er || err);
});
stream.fd = null;
}
function importFd(stream, options) {
if (typeof options.fd === 'number') {
// When fd is a raw descriptor, we must keep our fingers crossed
// that the descriptor won't get closed, or worse, replaced with
// another one
// https://github.com/nodejs/node/issues/35862
stream[kFs] = options.fs || fs;
return options.fd;
} else if (typeof options.fd === 'object' &&
options.fd instanceof FileHandle) {
// When fd is a FileHandle we can listen for 'close' events
if (options.fs) {
// FileHandle is not supported with custom fs operations
throw new ERR_METHOD_NOT_IMPLEMENTED('FileHandle with fs');
}
stream[kHandle] = options.fd;
stream[kFs] = FileHandleOperations(stream[kHandle]);
stream[kHandle][kRef]();
options.fd.on('close', FunctionPrototypeBind(stream.close, stream));
return options.fd.fd;
}
throw new ERR_INVALID_ARG_TYPE('options.fd',
['number', 'FileHandle'], options.fd);
}
function ReadStream(path, options) {
if (!(this instanceof ReadStream))
return new ReadStream(path, options);
// A little bit bigger buffer and water marks by default
options = copyObject(getOptions(options, kEmptyObject));
if (options.highWaterMark === undefined)
options.highWaterMark = 64 * 1024;
if (options.autoDestroy === undefined) {
options.autoDestroy = false;
}
if (options.fd == null) {
this.fd = null;
this[kFs] = options.fs || fs;
validateFunction(this[kFs].open, 'options.fs.open');
// Path will be ignored when fd is specified, so it can be falsy
this.path = toPathIfFileURL(path);
this.flags = options.flags === undefined ? 'r' : options.flags;
this.mode = options.mode === undefined ? 0o666 : options.mode;
validatePath(this.path);
} else {
this.fd = getValidatedFd(importFd(this, options));
}
options.autoDestroy = options.autoClose === undefined ?
true : options.autoClose;
validateFunction(this[kFs].read, 'options.fs.read');
if (options.autoDestroy) {
validateFunction(this[kFs].close, 'options.fs.close');
}
this.start = options.start;
this.end = options.end;
this.pos = undefined;
this.bytesRead = 0;
this[kIsPerformingIO] = false;
if (this.start !== undefined) {
validateInteger(this.start, 'start', 0);
this.pos = this.start;
}
if (this.end === undefined) {
this.end = Infinity;
} else if (this.end !== Infinity) {
validateInteger(this.end, 'end', 0);
if (this.start !== undefined && this.start > this.end) {
throw new ERR_OUT_OF_RANGE(
'start',
`<= "end" (here: ${this.end})`,
this.start,
);
}
}
ReflectApply(Readable, this, [options]);
}
ObjectSetPrototypeOf(ReadStream.prototype, Readable.prototype);
ObjectSetPrototypeOf(ReadStream, Readable);
ObjectDefineProperty(ReadStream.prototype, 'autoClose', {
__proto__: null,
get() {
return this._readableState.autoDestroy;
},
set(val) {
this._readableState.autoDestroy = val;
},
});
const openReadFs = deprecate(function() {
// Noop.
}, 'ReadStream.prototype.open() is deprecated', 'DEP0135');
ReadStream.prototype.open = openReadFs;
ReadStream.prototype._construct = _construct;
ReadStream.prototype._read = function(n) {
n = this.pos !== undefined ?
MathMin(this.end - this.pos + 1, n) :
MathMin(this.end - this.bytesRead + 1, n);
if (n <= 0) {
this.push(null);
return;
}
const buf = Buffer.allocUnsafeSlow(n);
this[kIsPerformingIO] = true;
this[kFs]
.read(this.fd, buf, 0, n, this.pos, (er, bytesRead, buf) => {
this[kIsPerformingIO] = false;
// Tell ._destroy() that it's safe to close the fd now.
if (this.destroyed) {
this.emit(kIoDone, er);
return;
}
if (er) {
errorOrDestroy(this, er);
} else if (bytesRead > 0) {
if (this.pos !== undefined) {
this.pos += bytesRead;
}
this.bytesRead += bytesRead;
if (bytesRead !== buf.length) {
// Slow path. Shrink to fit.
// Copy instead of slice so that we don't retain
// large backing buffer for small reads.
const dst = Buffer.allocUnsafeSlow(bytesRead);
buf.copy(dst, 0, 0, bytesRead);
buf = dst;
}
this.push(buf);
} else {
this.push(null);
}
});
};
ReadStream.prototype._destroy = function(err, cb) {
// Usually for async IO it is safe to close a file descriptor
// even when there are pending operations. However, due to platform
// differences file IO is implemented using synchronous operations
// running in a thread pool. Therefore, file descriptors are not safe
// to close while used in a pending read or write operation. Wait for
// any pending IO (kIsPerformingIO) to complete (kIoDone).
if (this[kIsPerformingIO]) {
this.once(kIoDone, (er) => close(this, err || er, cb));
} else {
close(this, err, cb);
}
};
ReadStream.prototype.close = function(cb) {
if (typeof cb === 'function') finished(this, cb);
this.destroy();
};
ObjectDefineProperty(ReadStream.prototype, 'pending', {
__proto__: null,
get() { return this.fd === null; },
configurable: true,
});
function WriteStream(path, options) {
if (!(this instanceof WriteStream))
return new WriteStream(path, options);
options = copyObject(getOptions(options, kEmptyObject));
// Only buffers are supported.
options.decodeStrings = true;
if (options.fd == null) {
this.fd = null;
this[kFs] = options.fs || fs;
validateFunction(this[kFs].open, 'options.fs.open');
// Path will be ignored when fd is specified, so it can be falsy
this.path = toPathIfFileURL(path);
this.flags = options.flags === undefined ? 'w' : options.flags;
this.mode = options.mode === undefined ? 0o666 : options.mode;
validatePath(this.path);
} else {
this.fd = getValidatedFd(importFd(this, options));
}
options.autoDestroy = options.autoClose === undefined ?
true : options.autoClose;
if (!this[kFs].write && !this[kFs].writev) {
throw new ERR_INVALID_ARG_TYPE('options.fs.write', 'function',
this[kFs].write);
}
if (this[kFs].write) {
validateFunction(this[kFs].write, 'options.fs.write');
}
if (this[kFs].writev) {
validateFunction(this[kFs].writev, 'options.fs.writev');
}
if (options.autoDestroy) {
validateFunction(this[kFs].close, 'options.fs.close');
}
this.flush = options.flush;
if (this.flush == null) {
this.flush = false;
} else {
validateBoolean(this.flush, 'options.flush');
validateFunction(this[kFs].fsync, 'options.fs.fsync');
}
// It's enough to override either, in which case only one will be used.
if (!this[kFs].write) {
this._write = null;
}
if (!this[kFs].writev) {
this._writev = null;
}
this.start = options.start;
this.pos = undefined;
this.bytesWritten = 0;
this[kIsPerformingIO] = false;
if (this.start !== undefined) {
validateInteger(this.start, 'start', 0);
this.pos = this.start;
}
ReflectApply(Writable, this, [options]);
if (options.encoding)
this.setDefaultEncoding(options.encoding);
}
ObjectSetPrototypeOf(WriteStream.prototype, Writable.prototype);
ObjectSetPrototypeOf(WriteStream, Writable);
ObjectDefineProperty(WriteStream.prototype, 'autoClose', {
__proto__: null,
get() {
return this._writableState.autoDestroy;
},
set(val) {
this._writableState.autoDestroy = val;
},
});
const openWriteFs = deprecate(function() {
// Noop.
}, 'WriteStream.prototype.open() is deprecated', 'DEP0135');
WriteStream.prototype.open = openWriteFs;
WriteStream.prototype._construct = _construct;
function writeAll(data, size, pos, cb, retries = 0) {
this[kFs].write(this.fd, data, 0, size, pos, (er, bytesWritten, buffer) => {
// No data currently available and operation should be retried later.
if (er?.code === 'EAGAIN') {
er = null;
bytesWritten = 0;
}
if (this.destroyed || er) {
return cb(er || new ERR_STREAM_DESTROYED('write'));
}
this.bytesWritten += bytesWritten;
retries = bytesWritten ? 0 : retries + 1;
size -= bytesWritten;
pos += bytesWritten;
// Try writing non-zero number of bytes up to 5 times.
if (retries > 5) {
cb(new ERR_SYSTEM_ERROR('write failed'));
} else if (size) {
writeAll.call(this, buffer.slice(bytesWritten), size, pos, cb, retries);
} else {
cb();
}
});
}
function writevAll(chunks, size, pos, cb, retries = 0) {
this[kFs].writev(this.fd, chunks, this.pos, (er, bytesWritten, buffers) => {
// No data currently available and operation should be retried later.
if (er?.code === 'EAGAIN') {
er = null;
bytesWritten = 0;
}
if (this.destroyed || er) {
return cb(er || new ERR_STREAM_DESTROYED('writev'));
}
this.bytesWritten += bytesWritten;
retries = bytesWritten ? 0 : retries + 1;
size -= bytesWritten;
pos += bytesWritten;
// Try writing non-zero number of bytes up to 5 times.
if (retries > 5) {
cb(new ERR_SYSTEM_ERROR('writev failed'));
} else if (size) {
writevAll.call(this, [Buffer.concat(buffers).slice(bytesWritten)], size, pos, cb, retries);
} else {
cb();
}
});
}
WriteStream.prototype._write = function(data, encoding, cb) {
this[kIsPerformingIO] = true;
writeAll.call(this, data, data.length, this.pos, (er) => {
this[kIsPerformingIO] = false;
if (this.destroyed) {
// Tell ._destroy() that it's safe to close the fd now.
cb(er);
return this.emit(kIoDone, er);
}
cb(er);
});
if (this.pos !== undefined)
this.pos += data.length;
};
WriteStream.prototype._writev = function(data, cb) {
const len = data.length;
const chunks = new Array(len);
let size = 0;
for (let i = 0; i < len; i++) {
const chunk = data[i].chunk;
chunks[i] = chunk;
size += chunk.length;
}
this[kIsPerformingIO] = true;
writevAll.call(this, chunks, size, this.pos, (er) => {
this[kIsPerformingIO] = false;
if (this.destroyed) {
// Tell ._destroy() that it's safe to close the fd now.
cb(er);
return this.emit(kIoDone, er);
}
cb(er);
});
if (this.pos !== undefined)
this.pos += size;
};
WriteStream.prototype._destroy = function(err, cb) {
// Usually for async IO it is safe to close a file descriptor
// even when there are pending operations. However, due to platform
// differences file IO is implemented using synchronous operations
// running in a thread pool. Therefore, file descriptors are not safe
// to close while used in a pending read or write operation. Wait for
// any pending IO (kIsPerformingIO) to complete (kIoDone).
if (this[kIsPerformingIO]) {
this.once(kIoDone, (er) => close(this, err || er, cb));
} else {
close(this, err, cb);
}
};
WriteStream.prototype.close = function(cb) {
if (cb) {
if (this.closed) {
process.nextTick(cb);
return;
}
this.on('close', cb);
}
// If we are not autoClosing, we should call
// destroy on 'finish'.
if (!this.autoClose) {
this.on('finish', this.destroy);
}
// We use end() instead of destroy() because of
// https://github.com/nodejs/node/issues/2006
this.end();
};
// There is no shutdown() for files.
WriteStream.prototype.destroySoon = WriteStream.prototype.end;
ObjectDefineProperty(WriteStream.prototype, 'pending', {
__proto__: null,
get() { return this.fd === null; },
configurable: true,
});
module.exports = {
ReadStream,
WriteStream,
};
Zerion Mini Shell 1.0