[ADD] Memory: memory will be use for history, target the node to redraw...

Author: Gorash

packages/core/src/Memory/Memory.ts

@@ -0,0 +1,138 @@
+import {
+    AllowedMemory,
+    AllowedObject,
+    MemoryVersionable,
+    MemoryTypeArray,
+    MemoryTypeObject,
+    MemoryTypeSet,
+} from './Memory';
+import { proxifyObject } from './VersionableObject';
+import { proxifyArray } from './VersionableArray';
+import { proxifySet } from './VersionableSet';
+import {
+    memoryProxyNotVersionableKey,
+    NotVersionableErrorMessage,
+    VersionableAllreadyVersionableErrorMessage,
+    memoryProxyPramsKey,
+} from './const';
+
+export class ProxyUniqID extends Number {}
+ProxyUniqID.prototype[memoryProxyNotVersionableKey] = true;
+
+let MemoryID = 0;
+export function generateMemoryID(): ProxyUniqID {
+    // Unique ID (not really related to memory)
+    return new ProxyUniqID(++MemoryID);
+}
+
+// const key = new ProxyUniqID(1);
+// const rec = {};
+// rec[key as number] = 4;
+
+// Magic memory key that is set on the object through a symbol (inaccessible for
+// others). It stores everything that is useful for the memory to handle this object.
+export interface VersionableParams {
+    ID: ProxyUniqID; // id du couple (proxy, object) en mémoire (number extension)
+    memory?: MemoryVersionable; // interface for versionale to access memory (since we don't want to give them the true memory object !)
+    proxy: AllowedObject; // proxy itself (what we return, what people actually manipulate)
+    object: AllowedObject; // Object that is proxified (it is synchronized with the proxy because the proxy updates it at some points ... -- not the Set !)
+    linkCallback: (memory: MemoryVersionable) => void; // function to call when this versionable is linked to a memory
+    sync: () => void;
+    itsme: (obj: AllowedMemory) => boolean;
+    MemoryType: typeof MemoryTypeObject | typeof MemoryTypeArray | typeof MemoryTypeSet;
+    willBeRootDiff?: true; // is it a standalone object or does it only makes sense as part of an other object's structure ?
+}
+
+// queue of stuff to proxify
+const objectStackToProxify = new Map<AllowedMemory, Array<(proxy: AllowedMemory) => void>>();
+
+export function makeVersionable<T extends AllowedMemory>(customClass: T): T {
+    const params = customClass[memoryProxyPramsKey] as VersionableParams;
+    if (params) {
+        if (params.object === customClass) {
+            VersionableAllreadyVersionableErrorMessage();
+        }
+        if (params && params.itsme(customClass)) {
+            return customClass;
+        }
+    }
+    const proxy = _proxify(customClass);
+    objectStackToProxify.forEach((callbacks, torototo) => {
+        objectStackToProxify.delete(torototo);
+        const proxy = _proxify(torototo);
+        callbacks.forEach(callback => callback(proxy));
+    });
+    return proxy;
+}
+export function createProxyWithVersionable<T extends AllowedMemory>(
+    proxy: T,
+    handler: ProxyHandler<object>,
+): T {
+    const newProxy = new Proxy(proxy as object, handler);
+    proxy[memoryProxyPramsKey].proxy = newProxy;
+    return newProxy as T;
+}
+export function markNotVersionable(customClass: AllowedMemory): void {
+    customClass[memoryProxyNotVersionableKey] = true;
+}
+// the argument can be anything actually, not necessarily a class
+export function checkIfProxy<T extends AllowedMemory>(customClass: T): T {
+    if (
+        typeof customClass !== 'object' ||
+        customClass === null ||
+        customClass[memoryProxyNotVersionableKey] // this is set by the user
+    ) {
+        return customClass;
+    }
+
+    const params = customClass[memoryProxyPramsKey];
+    if (params) {
+        if (params.object === customClass) {
+            VersionableAllreadyVersionableErrorMessage();
+        }
+        if (params.itsme(customClass)) {
+            // Already versioned ! (we could have inherited from the `params` of
+            // another, already versioned object, but we might not)
+            return customClass;
+        }
+    }
+
+    NotVersionableErrorMessage();
+}
+function _proxify<T extends AllowedMemory>(customClass: T): T {
+    const params = customClass[memoryProxyPramsKey];
+    if (params && params.itsme(customClass)) {
+        return params.proxy;
+    }
+    let proxy: T;
+    if (customClass instanceof Set) {
+        proxy = proxifySet(customClass) as T;
+    } else if (customClass instanceof Array) {
+        proxy = proxifyArray(customClass) as T;
+    } else {
+        proxy = proxifyObject(customClass as Record<string, AllowedMemory>) as T;
+    }
+    return proxy;
+}
+// Recursive proxification is very limited because of callback depth. To
+// circumvent this issue, we queue the proxification of children.
+export function stackedProxify<T extends AllowedMemory>(
+    customClass: T,
+    callback: (proxy: T) => void,
+): void {
+    if (
+        !customClass ||
+        typeof customClass !== 'object' ||
+        customClass[memoryProxyNotVersionableKey]
+    ) {
+        callback(customClass);
+        return;
+    }
+    const params = customClass[memoryProxyPramsKey];
+    if (params) {
+        callback(params.proxy);
+    }
+    const callbacks = objectStackToProxify.get(customClass) || [];
+    objectStackToProxify.set(customClass, callbacks);
+    callbacks.push(callback);
+}