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denoland-deno/ext/node/polyfills/internal/streams/utils.mjs

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// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
// Copyright Joyent and Node contributors. All rights reserved. MIT license.
// deno-lint-ignore-file
const kIsDisturbed = Symbol("kIsDisturbed");
function isReadableNodeStream(obj) {
return !!(
obj &&
typeof obj.pipe === "function" &&
typeof obj.on === "function" &&
(!obj._writableState || obj._readableState?.readable !== false) && // Duplex
(!obj._writableState || obj._readableState) // Writable has .pipe.
);
}
function isWritableNodeStream(obj) {
return !!(
obj &&
typeof obj.write === "function" &&
typeof obj.on === "function" &&
(!obj._readableState || obj._writableState?.writable !== false) // Duplex
);
}
function isDuplexNodeStream(obj) {
return !!(
obj &&
(typeof obj.pipe === "function" && obj._readableState) &&
typeof obj.on === "function" &&
typeof obj.write === "function"
);
}
function isNodeStream(obj) {
return (
obj &&
(
obj._readableState ||
obj._writableState ||
(typeof obj.write === "function" && typeof obj.on === "function") ||
(typeof obj.pipe === "function" && typeof obj.on === "function")
)
);
}
function isDestroyed(stream) {
if (!isNodeStream(stream)) return null;
const wState = stream._writableState;
const rState = stream._readableState;
const state = wState || rState;
return !!(stream.destroyed || state?.destroyed);
}
// Have been end():d.
function isWritableEnded(stream) {
if (!isWritableNodeStream(stream)) return null;
if (stream.writableEnded === true) return true;
const wState = stream._writableState;
if (wState?.errored) return false;
if (typeof wState?.ended !== "boolean") return null;
return wState.ended;
}
// Have emitted 'finish'.
function isWritableFinished(stream, strict) {
if (!isWritableNodeStream(stream)) return null;
if (stream.writableFinished === true) return true;
const wState = stream._writableState;
if (wState?.errored) return false;
if (typeof wState?.finished !== "boolean") return null;
return !!(
wState.finished ||
(strict === false && wState.ended === true && wState.length === 0)
);
}
// Have been push(null):d.
function isReadableEnded(stream) {
if (!isReadableNodeStream(stream)) return null;
if (stream.readableEnded === true) return true;
const rState = stream._readableState;
if (!rState || rState.errored) return false;
if (typeof rState?.ended !== "boolean") return null;
return rState.ended;
}
// Have emitted 'end'.
function isReadableFinished(stream, strict) {
if (!isReadableNodeStream(stream)) return null;
const rState = stream._readableState;
if (rState?.errored) return false;
if (typeof rState?.endEmitted !== "boolean") return null;
return !!(
rState.endEmitted ||
(strict === false && rState.ended === true && rState.length === 0)
);
}
function isDisturbed(stream) {
return !!(stream && (
stream.readableDidRead ||
stream.readableAborted ||
stream[kIsDisturbed]
));
}
function isReadable(stream) {
const r = isReadableNodeStream(stream);
if (r === null || typeof stream?.readable !== "boolean") return null;
if (isDestroyed(stream)) return false;
return r && stream.readable && !isReadableFinished(stream);
}
function isWritable(stream) {
const r = isWritableNodeStream(stream);
if (r === null || typeof stream?.writable !== "boolean") return null;
if (isDestroyed(stream)) return false;
return r && stream.writable && !isWritableEnded(stream);
}
function isFinished(stream, opts) {
if (!isNodeStream(stream)) {
return null;
}
if (isDestroyed(stream)) {
return true;
}
if (opts?.readable !== false && isReadable(stream)) {
return false;
}
if (opts?.writable !== false && isWritable(stream)) {
return false;
}
return true;
}
function isClosed(stream) {
if (!isNodeStream(stream)) {
return null;
}
const wState = stream._writableState;
const rState = stream._readableState;
if (
typeof wState?.closed === "boolean" ||
typeof rState?.closed === "boolean"
) {
return wState?.closed || rState?.closed;
}
if (typeof stream._closed === "boolean" && isOutgoingMessage(stream)) {
return stream._closed;
}
return null;
}
function isOutgoingMessage(stream) {
return (
typeof stream._closed === "boolean" &&
typeof stream._defaultKeepAlive === "boolean" &&
typeof stream._removedConnection === "boolean" &&
typeof stream._removedContLen === "boolean"
);
}
function isServerResponse(stream) {
return (
typeof stream._sent100 === "boolean" &&
isOutgoingMessage(stream)
);
}
function isServerRequest(stream) {
return (
typeof stream._consuming === "boolean" &&
typeof stream._dumped === "boolean" &&
stream.req?.upgradeOrConnect === undefined
);
}
function willEmitClose(stream) {
if (!isNodeStream(stream)) return null;
const wState = stream._writableState;
const rState = stream._readableState;
const state = wState || rState;
return (!state && isServerResponse(stream)) || !!(
state &&
state.autoDestroy &&
state.emitClose &&
state.closed === false
);
}
export default {
isDisturbed,
kIsDisturbed,
isClosed,
isDestroyed,
isDuplexNodeStream,
isFinished,
isReadable,
isReadableNodeStream,
isReadableEnded,
isReadableFinished,
isNodeStream,
isWritable,
isWritableNodeStream,
isWritableEnded,
isWritableFinished,
isServerRequest,
isServerResponse,
willEmitClose,
};
export {
isClosed,
isDestroyed,
isDisturbed,
isDuplexNodeStream,
isFinished,
isNodeStream,
isReadable,
isReadableEnded,
isReadableFinished,
isReadableNodeStream,
isServerRequest,
isServerResponse,
isWritable,
isWritableEnded,
isWritableFinished,
isWritableNodeStream,
kIsDisturbed,
willEmitClose,
};