BUGFIX: Memory Leak in NetscriptPorts (#399)

Co-authored-by: Snarling <84951833+Snarling@users.noreply.github.com>

src/NetscriptPort.ts

@@ -1,79 +1,100 @@
 import { Settings } from "./Settings/Settings";
+import { NetscriptPort } from "@nsdefs";
+import { NetscriptPorts } from "./NetscriptWorker";
 
 type PortData = string | number;
 type Resolver = () => void;
-export interface IPort {
-  write: (value: unknown) => PortData | null;
-  tryWrite: (value: unknown) => boolean;
-  read: () => PortData;
-  peek: () => PortData;
-  nextWrite: () => Promise<void>;
-  full: () => boolean;
-  empty: () => boolean;
-  clear: () => void;
+const emptyPortData = "NULL PORT DATA";
+/** The object property is for typechecking and is not present at runtime */
+export type PortNumber = number & { __PortNumber: true };
+
+/** Gets the numbered port, initializing it if it doesn't already exist.
+ * Only using for functions that write data/resolvers. Use NetscriptPorts.get(n) for */
+export function getPort(n: PortNumber) {
+  let port = NetscriptPorts.get(n);
+  if (port) return port;
+  port = new Port();
+  NetscriptPorts.set(n, port);
+  return port;
 }
 
-export function NetscriptPort(): IPort {
-  const data: PortData[] = [];
-  const resolvers: Resolver[] = [];
-
+export class Port {
+  data: PortData[] = [];
+  resolvers: Resolver[] = [];
+}
+export function portHandle(n: PortNumber): NetscriptPort {
   return {
-    write: (value) => {
-      if (typeof value !== "number" && typeof value !== "string") {
-        throw new Error(
-          `port.write: Tried to write type ${typeof value}. Only string and number types may be written to ports.`,
-        );
-      }
-      data.push(value);
-      while (resolvers.length > 0) {
-        (resolvers.pop() as Resolver)();
-      }
-      if (data.length > Settings.MaxPortCapacity) {
-        return data.shift() as PortData;
-      }
-      return null;
-    },
-
-    tryWrite: (value) => {
-      if (typeof value != "number" && typeof value != "string") {
-        throw new Error(
-          `port.write: Tried to write type ${typeof value}. Only string and number types may be written to ports.`,
-        );
-      }
-      if (data.length >= Settings.MaxPortCapacity) {
-        return false;
-      }
-      data.push(value);
-      while (resolvers.length > 0) {
-        (resolvers.pop() as Resolver)();
-      }
-      return true;
-    },
-
-    read: () => {
-      if (data.length === 0) return "NULL PORT DATA";
-      return data.shift() as PortData;
-    },
-
-    peek: () => {
-      if (data.length === 0) return "NULL PORT DATA";
-      return data[0];
-    },
-
-    nextWrite: () => {
-      return new Promise((res) => resolvers.push(res));
-    },
-
-    full: () => {
-      return data.length == Settings.MaxPortCapacity;
-    },
-
-    empty: () => {
-      return data.length === 0;
-    },
-
-    clear: () => {
-      data.length = 0;
-    },
+    write: (value: unknown) => writePort(n, value),
+    tryWrite: (value: unknown) => tryWritePort(n, value),
+    read: () => readPort(n),
+    peek: () => peekPort(n),
+    nextWrite: () => nextWritePort(n),
+    full: () => isFullPort(n),
+    empty: () => isEmptyPort(n),
+    clear: () => clearPort(n),
   };
 }
+
+export function writePort(n: PortNumber, value: unknown): PortData | null {
+  if (typeof value !== "number" && typeof value !== "string") {
+    throw new Error(
+      `port.write: Tried to write type ${typeof value}. Only string and number types may be written to ports.`,
+    );
+  }
+  const { data, resolvers } = getPort(n);
+  data.push(value);
+  while (resolvers.length > 0) (resolvers.pop() as Resolver)();
+  if (data.length > Settings.MaxPortCapacity) return data.shift() as PortData;
+  return null;
+}
+
+export function tryWritePort(n: PortNumber, value: unknown): boolean {
+  if (typeof value != "number" && typeof value != "string") {
+    throw new Error(
+      `port.write: Tried to write type ${typeof value}. Only string and number types may be written to ports.`,
+    );
+  }
+  const { data, resolvers } = getPort(n);
+  if (data.length >= Settings.MaxPortCapacity) return false;
+  data.push(value);
+  while (resolvers.length > 0) (resolvers.pop() as Resolver)();
+  return true;
+}
+
+export function readPort(n: PortNumber): PortData {
+  const port = NetscriptPorts.get(n);
+  if (!port || !port.data.length) return emptyPortData;
+  const returnVal = port.data.shift() as PortData;
+  if (!port.data.length && !port.resolvers.length) NetscriptPorts.delete(n);
+  return returnVal;
+}
+
+export function peekPort(n: PortNumber): PortData {
+  const port = NetscriptPorts.get(n);
+  if (!port || !port.data.length) return emptyPortData;
+  return port.data[0];
+}
+
+function nextWritePort(n: PortNumber) {
+  const { resolvers } = getPort(n);
+  return new Promise<void>((res) => resolvers.push(res as Resolver));
+}
+
+function isFullPort(n: PortNumber) {
+  const port = NetscriptPorts.get(n);
+  if (!port) return false;
+  return port.data.length >= Settings.MaxPortCapacity;
+}
+
+function isEmptyPort(n: PortNumber) {
+  const port = NetscriptPorts.get(n);
+  if (!port) return true;
+  return port.data.length === 0;
+}
+
+export function clearPort(n: PortNumber) {
+  const port = NetscriptPorts.get(n);
+  if (!port) return;
+  if (!port.resolvers.length) NetscriptPorts.delete(n);
+  port.data.length = 0;
+}