Add support for jobs & queueables, migrations

- Create migration directives & migrators
- Modify Cache classes to support array manipulation
- Create Redis unit and RedisCache implementation
- Create Queueable base class and Queue class that uses Cache backend

src/support/CanonicalReceiver.ts

@@ -0,0 +1,61 @@
+import {AppClass} from '../lifecycle/AppClass'
+
+/**
+ * Interface for a class that receives its canonical resolver names upon load.
+ */
+export interface CanonicalReceiver {
+    setCanonicalResolver(fullyQualifiedResolver: string, unqualifiedResolver: string): void
+    getCanonicalResolver(): string | undefined
+    getFullyQualifiedCanonicalResolver(): string | undefined
+}
+
+/**
+ * Function that checks whether a given value satisfies the CanonicalReceiver interface.
+ * @param something
+ */
+export function isCanonicalReceiver(something: unknown): something is CanonicalReceiver {
+    return (
+        typeof something === 'function'
+        && typeof (something as any).setCanonicalResolver === 'function'
+        && (something as any).setCanonicalResolver.length >= 1
+        && typeof (something as any).getCanonicalResolver === 'function'
+        && (something as any).getCanonicalResolver.length === 0
+    )
+}
+
+/**
+ * Base class for canonical items that implements the CanonicalReceiver interface.
+ * That is, `isCanonicalReceiver(CanonicalItemClass) === true`.
+ */
+export class CanonicalItemClass extends AppClass {
+    /** The type-prefixed canonical resolver of this class, set by the startup unit. */
+    private static canonFullyQualifiedResolver?: string
+
+    /** The unqualified canonical resolver of this class, set by the startup unit. */
+    private static canonUnqualifiedResolver?: string
+
+    /**
+     * Sets the fully- and un-qualified canonical resolver strings. Intended for use
+     * by the Canonical unit.
+     * @param fullyQualifiedResolver
+     * @param unqualifiedResolver
+     */
+    public static setCanonicalResolver(fullyQualifiedResolver: string, unqualifiedResolver: string): void {
+        this.canonFullyQualifiedResolver = fullyQualifiedResolver
+        this.canonUnqualifiedResolver = unqualifiedResolver
+    }
+
+    /**
+     * Get the fully-qualified canonical resolver of this class, if one has been set.
+     */
+    public static getFullyQualifiedCanonicalResolver(): string | undefined {
+        return this.canonFullyQualifiedResolver
+    }
+
+    /**
+     * Get the unqualified canonical resolver of this class, if one has been set.
+     */
+    public static getCanonicalResolver(): string | undefined {
+        return this.canonUnqualifiedResolver
+    }
+}