Extension storage (#179)

src/engine/runtime.js

@@ -512,6 +512,12 @@ class Runtime extends EventEmitter {
          * Responsible for managing custom fonts.
          */
         this.fontManager = new FontManager(this);
+
+        /**
+         * Maps extension ID to a JSON-serializable value.
+         * @type {Object.<string, object>}
+         */
+        this.extensionStorage = {};
     }
 
     /**

src/engine/target.js

@@ -70,6 +70,12 @@ class Target extends EventEmitter {
          * @type {Object.<string, *>}
          */
         this._edgeActivatedHatValues = {};
+
+        /**
+         * Maps extension ID to a JSON-serializable value.
+         * @type {Object.<string, object>}
+         */
+        this.extensionStorage = {};
     }
 
     /**

src/serialization/sb3.js

@@ -634,6 +634,26 @@ const serializeTarget = function (target, extensions) {
     return obj;
 };
 
+/**
+ * @param {Record<string, unknown>} extensionStorage extensionStorage object
+ * @param {Set<string>} extensions extension IDs
+ * @returns {Record<string, unknown>|null}
+ */
+const serializeExtensionStorage = (extensionStorage, extensions) => {
+    const result = {};
+    let isEmpty = true;
+    for (const [key, value] of Object.entries(extensionStorage)) {
+        if (extensions.has(key) && value !== null && typeof value !== 'undefined') {
+            isEmpty = false;
+            result[key] = extensionStorage[key];
+        }
+    }
+    if (isEmpty) {
+        return null;
+    }
+    return result;
+};
+
 const getSimplifiedLayerOrdering = function (targets) {
     const layerOrders = targets.map(t => t.getLayerOrder());
     return MathUtil.reducedSortOrdering(layerOrders);
@@ -712,7 +732,17 @@ const serialize = function (runtime, targetId, {allowOptimization = true} = {})
         });
     }
 
-    const serializedTargets = flattenedOriginalTargets.map(t => serializeTarget(t, extensions));
+    const serializedTargets = flattenedOriginalTargets.map(t => serializeTarget(t, extensions))
+        .map((serialized, index) => {
+            // can't serialize extensionStorage until the list of used extensions is fully known
+            const target = originalTargetsToSerialize[index];
+            const targetExtensionStorage = serializeExtensionStorage(target.extensionStorage, extensions);
+            if (targetExtensionStorage) {
+                serialized.extensionStorage = targetExtensionStorage;
+            }
+            return serialized;
+        });
+
     const fonts = runtime.fontManager.serializeJSON();
 
     if (targetId) {
@@ -731,6 +761,11 @@ const serialize = function (runtime, targetId, {allowOptimization = true} = {})
         return serializedTargets[0];
     }
 
+    const globalExtensionStorage = serializeExtensionStorage(runtime.extensionStorage, extensions);
+    if (globalExtensionStorage) {
+        obj.extensionStorage = globalExtensionStorage;
+    }
+
     obj.targets = serializedTargets;
 
     obj.monitors = serializeMonitors(runtime.getMonitorState(), runtime, extensions);
@@ -1274,6 +1309,9 @@ const parseScratchObject = function (object, runtime, extensions, zip, assets) {
     if (Object.prototype.hasOwnProperty.call(object, 'draggable')) {
         target.draggable = object.draggable;
     }
+    if (Object.prototype.hasOwnProperty.call(object, 'extensionStorage')) {
+        target.extensionStorage = object.extensionStorage;
+    }
     Promise.all(costumePromises).then(costumes => {
         sprite.costumes = costumes;
     });
@@ -1501,6 +1539,9 @@ const deserialize = function (json, runtime, zip, isSingleSprite) {
         .then(targets => replaceUnsafeCharsInVariableIds(targets))
         .then(targets => {
             monitorObjects.map(monitorDesc => deserializeMonitor(monitorDesc, runtime, targets, extensions));
+            if (Object.prototype.hasOwnProperty.call(json, 'extensionStorage')) {
+                runtime.extensionStorage = json.extensionStorage;
+            }
             return targets;
         })
         .then(targets => ({

test/integration/tw_extension_storage.js

@@ -0,0 +1,169 @@
+const {test} = require('tap');
+const fs = require('fs');
+const path = require('path');
+const VirtualMachine = require('../../src/virtual-machine');
+const Sprite = require('../../src/sprites/sprite');
+const RenderedTarget = require('../../src/sprites/rendered-target');
+const sb3 = require('../../src/serialization/sb3');
+
+test('serialize data', t => {
+    const vm = new VirtualMachine();
+    const rt = vm.runtime;
+
+    const target1 = new RenderedTarget(new Sprite(null, rt), rt);
+    const target2 = new RenderedTarget(new Sprite(null, rt), rt);
+    rt.addTarget(target1);
+    rt.addTarget(target2);
+
+    t.same(sb3.serialize(rt).extensionStorage, undefined, 'global - nothing when no extensions');
+    t.same(
+        sb3.serialize(rt).targets.map(i => i.extensionStorage),
+        [undefined, undefined],
+        'sprites - nothing when no extensions'
+    );
+
+    vm.extensionManager._registerInternalExtension({
+        getInfo: () => ({
+            id: 'test1',
+            blocks: []
+        })
+    });
+    vm.extensionManager._registerInternalExtension({
+        getInfo: () => ({
+            id: 'test2',
+            blocks: []
+        })
+    });
+    vm.extensionManager._registerInternalExtension({
+        getInfo: () => ({
+            id: 'test3',
+            blocks: []
+        })
+    });
+
+    t.same(sb3.serialize(rt).extensionStorage, undefined, 'global - nothing when no storage');
+    t.same(
+        sb3.serialize(rt).targets.map(i => i.extensionStorage),
+        [undefined, undefined],
+        'sprites - nothing when no storage'
+    );
+
+    const topLevelBlockBase = {
+        // this is not interesting for this test
+        inputs: {},
+        fields: {},
+        topLevel: true,
+        next: null,
+        parent: null
+    };
+
+    target1.blocks.createBlock({
+        ...topLevelBlockBase,
+        id: 'block1',
+        opcode: 'test1_whatever'
+    });
+    target2.blocks.createBlock({
+        ...topLevelBlockBase,
+        id: 'block2',
+        opcode: 'test2_whatever'
+    });
+
+    target1.extensionStorage.test1 = 1234321;
+    t.same(sb3.serialize(rt, target1.id).extensionStorage, {
+        test1: 1234321
+    }, 'target1 alone has test1');
+    t.same(sb3.serialize(rt, target2.id).extensionStorage, undefined, 'target2 alone does not have test1');
+
+    target1.extensionStorage.test1 = null;
+    t.same(sb3.serialize(rt, target1.id).extensionStorage, undefined, 'null is not serialized');
+
+    target1.extensionStorage.test1 = undefined;
+    t.same(sb3.serialize(rt, target1.id).extensionStorage, undefined, 'undefined is not serialized');
+
+    target1.extensionStorage.test1 = {it: 'works'};
+    target1.extensionStorage.test2 = true;
+    target1.extensionStorage.test3 = {should_not: 'be_saved'};
+
+    target2.extensionStorage.test1 = ['ok'];
+    delete target2.extensionStorage.test2;
+    delete target2.extensionStorage.test3;
+
+    rt.extensionStorage.test1 = 'global ok';
+    delete rt.extensionStorage.test2;
+    rt.extensionStorage.test3 = ['dont save this'];
+
+    const json = sb3.serialize(rt);
+    t.same(json.extensionStorage, {
+        test1: 'global ok'
+    }, 'final - global has test1');
+    t.same(json.targets.map(i => i.extensionStorage), [
+        {
+            test1: {
+                it: 'works'
+            },
+            test2: true
+        },
+        {
+            test1: ['ok']
+        }
+    ], 'final - targets ok');
+    
+    t.end();
+});
+
+test('deserialize project with data', t => {
+    const vm = new VirtualMachine();
+
+    vm.extensionManager._registerInternalExtension({
+        getInfo: () => ({
+            id: 'test1',
+            blocks: []
+        })
+    });
+    vm.extensionManager._registerInternalExtension({
+        getInfo: () => ({
+            id: 'test2',
+            blocks: []
+        })
+    });
+    vm.extensionManager._registerInternalExtension({
+        getInfo: () => ({
+            id: 'test3',
+            blocks: []
+        })
+    });
+
+    // trick it into thinking the extensions are real and loaded...
+    vm.extensionManager._loadedExtensions.set('test1', 'invalid');
+    vm.extensionManager._loadedExtensions.set('test2', 'invalid');
+    vm.extensionManager._loadedExtensions.set('test3', 'invalid');
+
+    const fixture = fs.readFileSync(path.resolve(__dirname, '../fixtures/tw-extension-storage.sb3'));
+    vm.loadProject(fixture).then(() => {
+        t.same(vm.runtime.extensionStorage, {
+            test1: 'global ok'
+        }, 'deserialized global');
+        t.same(vm.runtime.targets[0].extensionStorage, {
+            test1: {
+                it: 'works'
+            },
+            test2: true
+        }, 'deserialized target 0');
+        t.same(vm.runtime.targets[1].extensionStorage, {
+            test1: ['ok']
+        }, 'deserialized target 1');
+        t.same(vm.runtime.targets[2].extensionStorage, {}, 'deserialized target 2');
+
+        t.end();
+    });
+});
+
+test('deserialize project with no data', t => {
+    const vm = new VirtualMachine();
+    const fixture = fs.readFileSync(path.resolve(__dirname, '../fixtures/tw-extension-storage-no-data.sb3'));
+    vm.loadProject(fixture).then(() => {
+        t.same(vm.runtime.extensionStorage, {}, 'deserialized global');
+        t.same(vm.runtime.targets[0].extensionStorage, {}, 'deserialized target 0');
+        t.end();
+    });
+});