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denoland-deno/cli/js/files.ts
dubiousjim acf0958e94
Rename name/filename arguments to path (#4227)
There's a lot of variation in doc comments and internal code about
whether the first parameter to file system calls is `path` or `name` or
`filename`. For consistency, have made it always be `path`.
2020-03-06 11:29:23 -05:00

363 lines
11 KiB
TypeScript

// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
import {
EOF,
Reader,
Writer,
Seeker,
Closer,
SeekMode,
SyncReader,
SyncWriter,
SyncSeeker
} from "./io.ts";
import { sendAsyncMinimal, sendSyncMinimal } from "./dispatch_minimal.ts";
import {
sendSync as sendSyncJson,
sendAsync as sendAsyncJson
} from "./dispatch_json.ts";
import { OPS_CACHE } from "./runtime.ts";
// This is done because read/write are extremely performance sensitive.
let OP_READ = -1;
let OP_WRITE = -1;
/** Synchronously open a file and return an instance of the `File` object.
*
* const file = Deno.openSync("/foo/bar.txt", { read: true, write: true });
*
* Requires `allow-read` and `allow-write` permissions depending on mode.
*/
export function openSync(path: string, mode?: OpenOptions): File;
/** Synchronously open a file and return an instance of the `File` object.
*
* const file = Deno.openSync("/foo/bar.txt", "r");
*
* Requires `allow-read` and `allow-write` permissions depending on mode.
*/
export function openSync(path: string, mode?: OpenMode): File;
/**@internal*/
export function openSync(
path: string,
modeOrOptions: OpenOptions | OpenMode = "r"
): File {
let mode = null;
let options = null;
if (typeof modeOrOptions === "string") {
mode = modeOrOptions;
} else {
checkOpenOptions(modeOrOptions);
options = modeOrOptions;
}
const rid = sendSyncJson("op_open", { path, options, mode });
return new File(rid);
}
/** Open a file and resolve to an instance of the `File` object.
*
* const file = await Deno.open("/foo/bar.txt", { read: true, write: true });
*
* Requires `allow-read` and `allow-write` permissions depending on mode.
*/
export async function open(path: string, options?: OpenOptions): Promise<File>;
/** Open a file and resolves to an instance of `Deno.File`.
*
* const file = await Deno.open("/foo/bar.txt, "w+");
*
* Requires `allow-read` and `allow-write` permissions depending on mode.
*/
export async function open(path: string, mode?: OpenMode): Promise<File>;
/**@internal*/
export async function open(
path: string,
modeOrOptions: OpenOptions | OpenMode = "r"
): Promise<File> {
let mode = null;
let options = null;
if (typeof modeOrOptions === "string") {
mode = modeOrOptions;
} else {
checkOpenOptions(modeOrOptions);
options = modeOrOptions;
}
const rid = await sendAsyncJson("op_open", {
path,
options,
mode
});
return new File(rid);
}
/** Creates a file if none exists or truncates an existing file and returns
* an instance of `Deno.File`.
*
* const file = Deno.createSync("/foo/bar.txt");
*
* Requires `allow-read` and `allow-write` permissions.
*/
export function createSync(path: string): File {
return openSync(path, "w+");
}
/** Creates a file if none exists or truncates an existing file and resolves to
* an instance of `Deno.File`.
*
* const file = await Deno.create("/foo/bar.txt");
*
* Requires `allow-read` and `allow-write` permissions.
*/
export function create(path: string): Promise<File> {
return open(path, "w+");
}
/** Synchronously read from a file ID into an array buffer.
*
* Returns `number | EOF` for the operation.
*
* const file = Deno.openSync("/foo/bar.txt");
* const buf = new Uint8Array(100);
* const nread = Deno.readSync(file.rid, buf);
* const text = new TextDecoder().decode(buf);
*/
export function readSync(rid: number, p: Uint8Array): number | EOF {
if (p.length == 0) {
return 0;
}
if (OP_READ < 0) {
OP_READ = OPS_CACHE["op_read"];
}
const nread = sendSyncMinimal(OP_READ, rid, p);
if (nread < 0) {
throw new Error("read error");
} else if (nread == 0) {
return EOF;
} else {
return nread;
}
}
/** Read from a resource ID into an array buffer.
*
* Resolves to the `number | EOF` for the operation.
*
* const file = await Deno.open("/foo/bar.txt");
* const buf = new Uint8Array(100);
* const nread = await Deno.read(file.rid, buf);
* const text = new TextDecoder().decode(buf);
*/
export async function read(rid: number, p: Uint8Array): Promise<number | EOF> {
if (p.length == 0) {
return 0;
}
if (OP_READ < 0) {
OP_READ = OPS_CACHE["op_read"];
}
const nread = await sendAsyncMinimal(OP_READ, rid, p);
if (nread < 0) {
throw new Error("read error");
} else if (nread == 0) {
return EOF;
} else {
return nread;
}
}
/** Synchronously write to the resource ID the contents of the array buffer.
*
* Resolves to the number of bytes written.
*
* const encoder = new TextEncoder();
* const data = encoder.encode("Hello world\n");
* const file = Deno.openSync("/foo/bar.txt", {create: true, write: true});
* Deno.writeSync(file.rid, data);
*/
export function writeSync(rid: number, p: Uint8Array): number {
if (OP_WRITE < 0) {
OP_WRITE = OPS_CACHE["op_write"];
}
const result = sendSyncMinimal(OP_WRITE, rid, p);
if (result < 0) {
throw new Error("write error");
} else {
return result;
}
}
/** Write to the resource ID the contents of the array buffer.
*
* Resolves to the number of bytes written.
*
* const encoder = new TextEncoder();
* const data = encoder.encode("Hello world\n");
* const file = await Deno.open("/foo/bar.txt", {create: true, write: true});
* await Deno.write(file.rid, data);
*/
export async function write(rid: number, p: Uint8Array): Promise<number> {
if (OP_WRITE < 0) {
OP_WRITE = OPS_CACHE["op_write"];
}
const result = await sendAsyncMinimal(OP_WRITE, rid, p);
if (result < 0) {
throw new Error("write error");
} else {
return result;
}
}
/** Synchronously seek a file ID to the given offset under mode given by `whence`.
*
* Returns the number of cursor position.
*
* const file = Deno.openSync("/foo/bar.txt");
* const position = Deno.seekSync(file.rid, 0, 0);
*/
export function seekSync(
rid: number,
offset: number,
whence: SeekMode
): number {
return sendSyncJson("op_seek", { rid, offset, whence });
}
/** Seek a file ID to the given offset under mode given by `whence`.
*
* Resolves with the number of cursor position.
*
* const file = await Deno.open("/foo/bar.txt");
* const position = await Deno.seek(file.rid, 0, 0);
*/
export async function seek(
rid: number,
offset: number,
whence: SeekMode
): Promise<number> {
return await sendAsyncJson("op_seek", { rid, offset, whence });
}
/** Close the given resource ID. */
export function close(rid: number): void {
sendSyncJson("op_close", { rid });
}
/** The Deno abstraction for reading and writing files. */
export class File
implements
Reader,
SyncReader,
Writer,
SyncWriter,
Seeker,
SyncSeeker,
Closer {
constructor(readonly rid: number) {}
write(p: Uint8Array): Promise<number> {
return write(this.rid, p);
}
writeSync(p: Uint8Array): number {
return writeSync(this.rid, p);
}
read(p: Uint8Array): Promise<number | EOF> {
return read(this.rid, p);
}
readSync(p: Uint8Array): number | EOF {
return readSync(this.rid, p);
}
seek(offset: number, whence: SeekMode): Promise<number> {
return seek(this.rid, offset, whence);
}
seekSync(offset: number, whence: SeekMode): number {
return seekSync(this.rid, offset, whence);
}
close(): void {
close(this.rid);
}
}
/** An instance of `Deno.File` for `stdin`. */
export const stdin = new File(0);
/** An instance of `Deno.File` for `stdout`. */
export const stdout = new File(1);
/** An instance of `Deno.File` for `stderr`. */
export const stderr = new File(2);
export interface OpenOptions {
/** Sets the option for read access. This option, when `true`, means that the
* file should be read-able if opened. */
read?: boolean;
/** Sets the option for write access. This option, when `true`, means that
* the file should be write-able if opened. If the file already exists,
* any write calls on it will overwrite its contents, by default without
* truncating it. */
write?: boolean;
/**Sets the option for the append mode. This option, when `true`, means that
* writes will append to a file instead of overwriting previous contents.
* Note that setting `{ write: true, append: true }` has the same effect as
* setting only `{ append: true }`. */
append?: boolean;
/** Sets the option for truncating a previous file. If a file is
* successfully opened with this option set it will truncate the file to `0`
* length if it already exists. The file must be opened with write access
* for truncate to work. */
truncate?: boolean;
/** Sets the option to allow creating a new file, if one doesn't already
* exist at the specified path. Requires write or append access to be
* used. */
create?: boolean;
/** Defaults to `false`. If set to `true`, no file, directory, or symlink is
* allowed to exist at the target location. Requires write or append
* access to be used. When createNew is set to `true`, create and truncate
* are ignored. */
createNew?: boolean;
}
/** A set of string literals which specify the open mode of a file.
*
* |Value |Description |
* |------|--------------------------------------------------------------------------------------------------|
* |`"r"` |Read-only. Default. Starts at beginning of file. |
* |`"r+"`|Read-write. Start at beginning of file. |
* |`"w"` |Write-only. Opens and truncates existing file or creates new one for writing only. |
* |`"w+"`|Read-write. Opens and truncates existing file or creates new one for writing and reading. |
* |`"a"` |Write-only. Opens existing file or creates new one. Each write appends content to the end of file.|
* |`"a+"`|Read-write. Behaves like `"a"` and allows to read from file. |
* |`"x"` |Write-only. Exclusive create - creates new file only if one doesn't exist already. |
* |`"x+"`|Read-write. Behaves like `x` and allows reading from file. |
*/
export type OpenMode = "r" | "r+" | "w" | "w+" | "a" | "a+" | "x" | "x+";
/** Check if OpenOptions is set to valid combination of options.
* @returns Tuple representing if openMode is valid and error message if it's not
* @internal
*/
function checkOpenOptions(options: OpenOptions): void {
if (Object.values(options).filter(val => val === true).length === 0) {
throw new Error("OpenOptions requires at least one option to be true");
}
if (options.truncate && !options.write) {
throw new Error("'truncate' option requires 'write' option");
}
const createOrCreateNewWithoutWriteOrAppend =
(options.create || options.createNew) && !(options.write || options.append);
if (createOrCreateNewWithoutWriteOrAppend) {
throw new Error(
"'create' or 'createNew' options require 'write' or 'append' option"
);
}
}