std/types.d.ts

91 lines
4.2 KiB
TypeScript

// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
// This module is browser compatible.
/** See the Contributing > Types section in the README for an explanation of this file. */
/** An abstract interface which when implemented provides an interface to read bytes into an array buffer asynchronously. */
export interface Reader {
/** Reads up to `p.byteLength` bytes into `p`. It resolves to the number of
* bytes read (`0` < `n` <= `p.byteLength`) and rejects if any error
* encountered. Even if `read()` resolves to `n` < `p.byteLength`, it may
* use all of `p` as scratch space during the call. If some data is
* available but not `p.byteLength` bytes, `read()` conventionally resolves
* to what is available instead of waiting for more.
*
* When `read()` encounters end-of-file condition, it resolves to EOF
* (`null`).
*
* When `read()` encounters an error, it rejects with an error.
*
* Callers should always process the `n` > `0` bytes returned before
* considering the EOF (`null`). Doing so correctly handles I/O errors that
* happen after reading some bytes and also both of the allowed EOF
* behaviors.
*
* Implementations should not retain a reference to `p`.
*
* Use iterateReader() from https://deno.land/std@$STD_VERSION/streams/iterate_reader.ts to turn a Reader into an
* AsyncIterator.
*/
read(p: Uint8Array): Promise<number | null>;
}
/** An abstract interface which when implemented provides an interface to read bytes into an array buffer synchronously. */
export interface ReaderSync {
/** Reads up to `p.byteLength` bytes into `p`. It resolves to the number
* of bytes read (`0` < `n` <= `p.byteLength`) and rejects if any error
* encountered. Even if `read()` returns `n` < `p.byteLength`, it may use
* all of `p` as scratch space during the call. If some data is available
* but not `p.byteLength` bytes, `read()` conventionally returns what is
* available instead of waiting for more.
*
* When `readSync()` encounters end-of-file condition, it returns EOF
* (`null`).
*
* When `readSync()` encounters an error, it throws with an error.
*
* Callers should always process the `n` > `0` bytes returned before
* considering the EOF (`null`). Doing so correctly handles I/O errors that happen
* after reading some bytes and also both of the allowed EOF behaviors.
*
* Implementations should not retain a reference to `p`.
*
* Use iterateReaderSync() from https://deno.land/std@$STD_VERSION/streams/iterate_reader.ts to turn a ReaderSync
* into an Iterator.
*/
readSync(p: Uint8Array): number | null;
}
/** An abstract interface which when implemented provides an interface to write bytes from an array buffer to a file/resource asynchronously. */
export interface Writer {
/** Writes `p.byteLength` bytes from `p` to the underlying data stream. It
* resolves to the number of bytes written from `p` (`0` <= `n` <=
* `p.byteLength`) or reject with the error encountered that caused the
* write to stop early. `write()` must reject with a non-null error if
* would resolve to `n` < `p.byteLength`. `write()` must not modify the
* slice data, even temporarily.
*
* Implementations should not retain a reference to `p`.
*/
write(p: Uint8Array): Promise<number>;
}
/** An abstract interface which when implemented provides an interface to write bytes from an array buffer to a file/resource synchronously. */
export interface WriterSync {
/** Writes `p.byteLength` bytes from `p` to the underlying data
* stream. It returns the number of bytes written from `p` (`0` <= `n`
* <= `p.byteLength`) and any error encountered that caused the write to
* stop early. `writeSync()` must throw a non-null error if it returns `n` <
* `p.byteLength`. `writeSync()` must not modify the slice data, even
* temporarily.
*
* Implementations should not retain a reference to `p`.
*/
writeSync(p: Uint8Array): number;
}
/** An abstract interface which when implemented provides an interface to close files/resources that were previously opened. */
export interface Closer {
/** Closes the resource, "freeing" the backing file/resource. */
close(): void;
}