@matrixai/async-init - npm Package Compare versions

Comparing version 1.4.0 to 1.5.0

dist/utils.d.ts

@@ -11,11 +11,16 @@ import type { MutexInterface } from 'async-mutex';
 declare const initLock: unique symbol;
+/**
+ * Single threaded write-preferring read write lock
+ */
 declare class RWLock {
+    protected readersLock: Mutex;
+    protected writersLock: Mutex;
+    protected readersRelease: MutexInterface.Releaser;
+    protected readerCountBlocked: number;
     protected _readerCount: number;
     protected _writerCount: number;
-    protected lock: Mutex;
-    protected release: MutexInterface.Releaser;
     get readerCount(): number;
     get writerCount(): number;
-    read<T>(f: () => Promise<T>): Promise<T>;
-    write<T>(f: () => Promise<T>): Promise<T>;
+    withRead<T>(f: () => Promise<T>): Promise<T>;
+    withWrite<T>(f: () => Promise<T>): Promise<T>;
     acquireRead(): Promise<() => void>;
@@ -22,0 +27,0 @@ acquireWrite(): Promise<() => void>;

dist/utils.js

@@ -18,10 +18,15 @@ "use strict";
 exports.initLock = initLock;
+/**
+ * Single threaded write-preferring read write lock
+ */
 class RWLock {
     constructor() {
+        this.readersLock = new async_mutex_1.Mutex();
+        this.writersLock = new async_mutex_1.Mutex();
+        this.readerCountBlocked = 0;
         this._readerCount = 0;
         this._writerCount = 0;
-        this.lock = new async_mutex_1.Mutex();
     }
     get readerCount() {
-        return this._readerCount;
+        return this._readerCount + this.readerCountBlocked;
     }
@@ -31,8 +36,4 @@ get writerCount() {
     }
-    async read(f) {
-        let readerCount = ++this._readerCount;
-        // The first reader locks
-        if (readerCount === 1) {
-            this.release = await this.lock.acquire();
-        }
+    async withRead(f) {
+        const release = await this.acquireRead();
         try {
@@ -42,12 +43,7 @@ return await f();
         finally {
-            readerCount = --this._readerCount;
-            // The last reader unlocks
-            if (readerCount === 0) {
-                this.release();
-            }
+            release();
         }
     }
-    async write(f) {
-        this.release = await this.lock.acquire();
-        ++this._writerCount;
+    async withWrite(f) {
+        const release = await this.acquireWrite();
         try {
@@ -57,11 +53,15 @@ return await f();
         finally {
-            --this._writerCount;
-            this.release();
+            release();
         }
     }
     async acquireRead() {
+        if (this._writerCount > 0) {
+            ++this.readerCountBlocked;
+            await this.writersLock.waitForUnlock();
+            --this.readerCountBlocked;
+        }
         const readerCount = ++this._readerCount;
         // The first reader locks
         if (readerCount === 1) {
-            this.release = await this.lock.acquire();
+            this.readersRelease = await this.readersLock.acquire();
         }
@@ -72,3 +72,3 @@ return () => {
             if (readerCount === 0) {
-                this.release();
+                this.readersRelease();
             }
@@ -78,14 +78,20 @@ };
     async acquireWrite() {
-        this.release = await this.lock.acquire();
         ++this._writerCount;
+        const writersRelease = await this.writersLock.acquire();
+        this.readersRelease = await this.readersLock.acquire();
         return () => {
+            this.readersRelease();
+            writersRelease();
             --this._writerCount;
-            this.release();
         };
     }
     isLocked() {
-        return this.lock.isLocked();
+        return this.readersLock.isLocked() || this.writersLock.isLocked();
     }
     async waitForUnlock() {
-        return this.lock.waitForUnlock();
+        await Promise.all([
+            this.readersLock.waitForUnlock(),
+            this.writersLock.waitForUnlock(),
+        ]);
+        return;
     }
@@ -92,0 +98,0 @@ }

package.json

 {
   "name": "@matrixai/async-init",
-  "version": "1.4.0",
+  "version": "1.5.0",
   "author": "Roger Qiu",
@@ -5,0 +5,0 @@ "description": "Asynchronous Initialisation and Deinitialisation Decorators",

README.md

@@ -93,6 +93,4 @@ # js-async-init
 
-Note that it is unsafe to call the create, destroy, start and stop methods concurrently with other method calls. There is no concurrency control. Instead a simple method of making the methods idempotent is used.
+The `start`, `stop`, and `destroy` calls are all concurrent-controlled with `RWLock`. They are idempotent and they are mutually exclusive between each other and any blocking `ready` decorated methods. Decorated methods can block `start`, `stop`, and `destroy`, but share a read lock between each other.
 
-Note that `start`, `stop` and `destroy` are idempotent. This means repeated calls are noops.
-
 Refer to https://gist.github.com/CMCDragonkai/1dbf5069d9efc11585c27cc774271584 for further the motivation of this library.
@@ -99,0 +97,0 @@

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Improved metrics

Total package byte prevSize

59932

increased by1.05%

Lines of code

735

increased by1.52%

Worsened metrics

Number of lines in readme file

140

decreased by-1.41%

No dependency changes