Commit

node_modules/mongodb/lib/cmap/wire_protocol/on_data.js

@@ -0,0 +1,111 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.onData = onData;
+const utils_1 = require("../../utils");
+/**
+ * onData is adapted from Node.js' events.on helper
+ * https://nodejs.org/api/events.html#eventsonemitter-eventname-options
+ *
+ * Returns an AsyncIterator that iterates each 'data' event emitted from emitter.
+ * It will reject upon an error event.
+ */
+function onData(emitter, { timeoutContext, signal }) {
+    signal?.throwIfAborted();
+    // Setup pending events and pending promise lists
+    /**
+     * When the caller has not yet called .next(), we store the
+     * value from the event in this list. Next time they call .next()
+     * we pull the first value out of this list and resolve a promise with it.
+     */
+    const unconsumedEvents = new utils_1.List();
+    /**
+     * When there has not yet been an event, a new promise will be created
+     * and implicitly stored in this list. When an event occurs we take the first
+     * promise in this list and resolve it.
+     */
+    const unconsumedPromises = new utils_1.List();
+    /**
+     * Stored an error created by an error event.
+     * This error will turn into a rejection for the subsequent .next() call
+     */
+    let error = null;
+    /** Set to true only after event listeners have been removed. */
+    let finished = false;
+    const iterator = {
+        next() {
+            // First, we consume all unread events
+            const value = unconsumedEvents.shift();
+            if (value != null) {
+                return Promise.resolve({ value, done: false });
+            }
+            // Then we error, if an error happened
+            // This happens one time if at all, because after 'error'
+            // we stop listening
+            if (error != null) {
+                const p = Promise.reject(error);
+                // Only the first element errors
+                error = null;
+                return p;
+            }
+            // If the iterator is finished, resolve to done
+            if (finished)
+                return closeHandler();
+            // Wait until an event happens
+            const { promise, resolve, reject } = (0, utils_1.promiseWithResolvers)();
+            unconsumedPromises.push({ resolve, reject });
+            return promise;
+        },
+        return() {
+            return closeHandler();
+        },
+        throw(err) {
+            errorHandler(err);
+            return Promise.resolve({ value: undefined, done: true });
+        },
+        [Symbol.asyncIterator]() {
+            return this;
+        },
+        async [Symbol.asyncDispose]() {
+            await closeHandler();
+        }
+    };
+    // Adding event handlers
+    emitter.on('data', eventHandler);
+    emitter.on('error', errorHandler);
+    const abortListener = (0, utils_1.addAbortListener)(signal, function () {
+        errorHandler(this.reason);
+    });
+    const timeoutForSocketRead = timeoutContext?.timeoutForSocketRead;
+    timeoutForSocketRead?.throwIfExpired();
+    timeoutForSocketRead?.then(undefined, errorHandler);
+    return iterator;
+    function eventHandler(value) {
+        const promise = unconsumedPromises.shift();
+        if (promise != null)
+            promise.resolve({ value, done: false });
+        else
+            unconsumedEvents.push(value);
+    }
+    function errorHandler(err) {
+        const promise = unconsumedPromises.shift();
+        if (promise != null)
+            promise.reject(err);
+        else
+            error = err;
+        void closeHandler();
+    }
+    function closeHandler() {
+        // Adding event handlers
+        emitter.off('data', eventHandler);
+        emitter.off('error', errorHandler);
+        abortListener?.[utils_1.kDispose]();
+        finished = true;
+        timeoutForSocketRead?.clear();
+        const doneResult = { value: undefined, done: finished };
+        for (const promise of unconsumedPromises) {
+            promise.resolve(doneResult);
+        }
+        return Promise.resolve(doneResult);
+    }
+}
+//# sourceMappingURL=on_data.js.map