From 4a67904a85e0dfde6409bd5137561f4e5c8e8d8f Mon Sep 17 00:00:00 2001
From: Sven Slootweg <admin@cryto.net>
Date: Sun, 19 Jul 2020 21:04:21 +0200
Subject: [PATCH] Rename, validate input, end/abort handlers, misc. fixes

---
 index.js     | 87 +++++++++++++++++++++++++++++++++++++++++++++++-----
 package.json |  8 +++--
 2 files changed, 85 insertions(+), 10 deletions(-)

diff --git a/index.js b/index.js
index 0e6e5f3..0993458 100644
--- a/index.js
+++ b/index.js
@@ -4,31 +4,102 @@ const Promise = require("bluebird");
 const propagateAbort = require("@ppstreams/propagate-abort");
 const propagatePeek = require("@ppstreams/propagate-peek");
 const { isEndOfStream } = require("@ppstreams/end-of-stream-marker");
+const { isAborted } = require("@ppstreams/aborted-marker");
+
+const { validateOptions } = require("@validatem/core");
+const required = require("@validatem/required");
+const isFunction = require("@validatem/is-function");
+const defaultTo = require("@validatem/default-to");
+
+// FIXME: Update other stream implementations to new API
+module.exports = function greedySinkStream(_options) {
+	let { onResult, onEnd, onAbort } = validateOptions(arguments, {
+		onResult: [ required, isFunction ],
+		onEnd: [ isFunction, defaultTo.literal(defaultOnEnd) ],
+		onAbort: [ isFunction, defaultTo.literal(defaultOnAbort) ]
+	});
+
+	let lastResult;
+	let onEndCalled = false;
+	let onEndResult;
+	let abortHandled = false;
+
+	function defaultOnEnd() {
+		// We return whatever value we got last from the specified onResult callback.
+		return lastResult;
+	}
+
+	function defaultOnAbort() {
+		// no-op
+	}
 
-module.exports = function greedySinkStream(description, callback) {
 	return {
-		description: `greedy sink stream (${description})`,
+		description: `greedy sink stream`,
 		abort: propagateAbort,
 		peek: propagatePeek,
 		read: function produceValue_greedySinkStream(source) {
-			let lastResult;
-
 			function attemptRead() {
 				return Promise.try(() => {
 					return source.read();
 				}).then((value) => {
-					return callback(value);
+					// FIXME: Document that you can pause the sink from the onResult callback, by returning a Promise that resolves when it should be resumed
+					return onResult(value);
 				}).then((result) => {
 					lastResult = result;
 
 					return attemptRead();
 				}).catch(isEndOfStream, () => {
-					/* Don't attempt to do another read, we're done. We return whatever value we got last from the specified callback. */
-					return lastResult;
+					/* Don't attempt to do another read, we're done.  */
+					if (onEndCalled) {
+						return onEndResult;
+					} else {
+						return Promise.try(() => {
+							return onEnd();
+						}).then((result) => {
+							onEndResult = result;
+							return result;
+						});
+					}
+				}).catch((error) => !isAborted(error), (error) => {
+					return Promise.try(() => {
+						return source.abort(error);
+					}).catch((abortError) => {
+						let message = [
+							`Tried to abort stream due to encountering an error, but the aborting itself failed`,
+							`Original error message: ${error.message}`,
+							`Abort failure message: ${abortError.message}`
+						].join("\n");
+
+						// FIXME: Make this some sort of chained error
+						let combinedError = new Error(message);
+						combinedError.stack = abortError.stack; // HACK
+						throw combinedError;
+					}).then(() => {
+						// Pass through the original error to the user
+						throw error;
+					});
+				}).catch(isAborted, (marker) => {
+					if (abortHandled === false) {
+						abortHandled = true;
+
+						return Promise.try(() => {
+							return onAbort();
+						}).then(() => {
+							if (marker.reason instanceof Error) {
+								// NOTE: This ensures that the original error causing the abort is thrown exactly once
+								throw marker.reason;
+							} else {
+								throw marker;
+							}
+						});
+					} else {
+						// Don't interfere, we only need special behaviour on the first occurrence
+						throw marker;
+					}
 				});
 			}
 
 			return attemptRead();
 		}
 	};
-};
\ No newline at end of file
+};
diff --git a/package.json b/package.json
index 404d487..7be796c 100644
--- a/package.json
+++ b/package.json
@@ -1,13 +1,17 @@
 {
-  "name": "@ppstreams/greedy-sink",
+  "name": "@ppstreams/simple-sink",
   "version": "0.1.0",
   "main": "index.js",
-  "repository": "http://git.cryto.net/ppstreams/greedy-sink.git",
+  "repository": "http://git.cryto.net/ppstreams/simple-sink.git",
   "author": "Sven Slootweg <admin@cryto.net>",
   "license": "WTFPL OR CC0-1.0",
   "dependencies": {
     "@ppstreams/propagate-abort": "^0.1.2",
     "@ppstreams/propagate-peek": "^0.1.0",
+    "@validatem/core": "^0.3.11",
+    "@validatem/default-to": "^0.1.0",
+    "@validatem/is-function": "^0.1.0",
+    "@validatem/required": "^0.1.1",
     "bluebird": "^3.5.4"
   }
 }