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Diffstat (limited to 'ext/node/polyfills/internal/streams/legacy.mjs')
| -rw-r--r-- | ext/node/polyfills/internal/streams/legacy.mjs | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/ext/node/polyfills/internal/streams/legacy.mjs b/ext/node/polyfills/internal/streams/legacy.mjs new file mode 100644 index 000000000..0de18956f --- /dev/null +++ b/ext/node/polyfills/internal/streams/legacy.mjs @@ -0,0 +1,113 @@ +// 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 + +import EE from "internal:deno_node/polyfills/events.ts"; + +function Stream(opts) { + EE.call(this, opts); +} +Object.setPrototypeOf(Stream.prototype, EE.prototype); +Object.setPrototypeOf(Stream, EE); + +Stream.prototype.pipe = function (dest, options) { + // deno-lint-ignore no-this-alias + const source = this; + + function ondata(chunk) { + if (dest.writable && dest.write(chunk) === false && source.pause) { + source.pause(); + } + } + + source.on("data", ondata); + + function ondrain() { + if (source.readable && source.resume) { + source.resume(); + } + } + + dest.on("drain", ondrain); + + // If the 'end' option is not supplied, dest.end() will be called when + // source gets the 'end' or 'close' events. Only dest.end() once. + if (!dest._isStdio && (!options || options.end !== false)) { + source.on("end", onend); + source.on("close", onclose); + } + + let didOnEnd = false; + function onend() { + if (didOnEnd) return; + didOnEnd = true; + + dest.end(); + } + + function onclose() { + if (didOnEnd) return; + didOnEnd = true; + + if (typeof dest.destroy === "function") dest.destroy(); + } + + // Don't leave dangling pipes when there are errors. + function onerror(er) { + cleanup(); + if (EE.listenerCount(this, "error") === 0) { + this.emit("error", er); + } + } + + prependListener(source, "error", onerror); + prependListener(dest, "error", onerror); + + // Remove all the event listeners that were added. + function cleanup() { + source.removeListener("data", ondata); + dest.removeListener("drain", ondrain); + + source.removeListener("end", onend); + source.removeListener("close", onclose); + + source.removeListener("error", onerror); + dest.removeListener("error", onerror); + + source.removeListener("end", cleanup); + source.removeListener("close", cleanup); + + dest.removeListener("close", cleanup); + } + + source.on("end", cleanup); + source.on("close", cleanup); + + dest.on("close", cleanup); + dest.emit("pipe", source); + + // Allow for unix-like usage: A.pipe(B).pipe(C) + return dest; +}; + +function prependListener(emitter, event, fn) { + // Sadly this is not cacheable as some libraries bundle their own + // event emitter implementation with them. + if (typeof emitter.prependListener === "function") { + return emitter.prependListener(event, fn); + } + + // This is a hack to make sure that our error handler is attached before any + // userland ones. NEVER DO THIS. This is here only because this code needs + // to continue to work with older versions of Node.js that do not include + // the prependListener() method. The goal is to eventually remove this hack. + if (!emitter._events || !emitter._events[event]) { + emitter.on(event, fn); + } else if (Array.isArray(emitter._events[event])) { + emitter._events[event].unshift(fn); + } else { + emitter._events[event] = [fn, emitter._events[event]]; + } +} + +export { prependListener, Stream }; |
