fix: stateShape causes accessor sharing

Agoric · Mar 30, 2023 · d7f9d82 · d7f9d82
1 parent 316deca
commit d7f9d82
Showing 1 changed file with 57 additions and 38 deletions.
diff --git a/packages/swingset-liveslots/src/virtualObjectManager.js b/packages/swingset-liveslots/src/virtualObjectManager.js
@@ -1,6 +1,6 @@
 /* eslint-disable no-use-before-define, jsdoc/require-returns-type */
 
-import { assert, Fail } from '@agoric/assert';
+import { assert, Fail, q } from '@agoric/assert';
 import { objectMap } from '@agoric/internal';
 import { assertPattern, mustMatch } from '@agoric/store';
 import { defendPrototype, defendPrototypeKit } from '@agoric/store/tools.js';
@@ -11,7 +11,6 @@ import { enumerateKeysWithPrefix } from './vatstore-iterators.js';
 /** @template T @typedef {import('@agoric/vat-data').DefineKindOptions<T>} DefineKindOptions */
 
 const { ownKeys } = Reflect;
-const { details: X, quote: q } = assert;
 
 // import { kdebug } from './kdebug.js';
 
@@ -598,20 +597,21 @@ export function makeVirtualObjectManager(
     let contextMapTemplate;
     let prototypeTemplate;
 
+    const statePrototype = {}; // Not frozen yet
+    const stateToInnerSelfMap = new WeakMap(); // from state to innerSelf
+
     harden(stateShape);
     stateShape === undefined ||
       passStyleOf(stateShape) === 'copyRecord' ||
-      assert.fail(X`A stateShape must be a copyRecord: ${q(stateShape)}`);
+      Fail`A stateShape must be a copyRecord: ${q(stateShape)}`;
     assertPattern(stateShape);
 
     const serializeSlot = (slotState, prop) => {
       if (stateShape !== undefined) {
         hasOwnPropertyOf(stateShape, prop) ||
-          assert.fail(
-            X`State must only have fields described by stateShape: ${q(
-              ownKeys(stateShape),
-            )}`,
-          );
+          Fail`State must only have fields described by stateShape: ${q(
+            ownKeys(stateShape),
+          )}`;
         mustMatch(slotState, stateShape[prop], prop);
       }
       return serialize(slotState);
@@ -621,16 +621,57 @@ export function makeVirtualObjectManager(
       const slotValue = unserialize(slotData);
       if (stateShape !== undefined) {
         hasOwnPropertyOf(stateShape, prop) ||
-          assert.fail(
-            X`State only has fields described by stateShape: ${q(
-              ownKeys(stateShape),
-            )}`,
-          );
+          Fail`State only has fields described by stateShape: ${q(
+            ownKeys(stateShape),
+          )}`;
         mustMatch(slotValue, stateShape[prop]);
       }
       return slotValue;
     };
 
+    const getInnerSelf = state => {
+      stateToInnerSelfMap.has(state) ||
+        Fail`state accessors can only be applied to state`;
+      let innerSelf = stateToInnerSelfMap.get(state);
+      if (innerSelf.rawState) {
+        cache.refresh(innerSelf);
+      } else {
+        innerSelf = cache.lookup(innerSelf.baseRef, true);
+        stateToInnerSelfMap.set(state, innerSelf);
+      }
+      return innerSelf;
+    };
+
+    const makeFieldDescriptor = prop => {
+      return harden({
+        get() {
+          const innerSelf = getInnerSelf(this);
+          return unserializeSlot(innerSelf.rawState[prop], prop);
+        },
+        set(value) {
+          const innerSelf = getInnerSelf(this);
+          const before = innerSelf.rawState[prop];
+          const after = serializeSlot(value, prop);
+          assertAcceptableSyscallCapdataSize([after]);
+          if (isDurable) {
+            after.slots.forEach((vref, index) => {
+              vrm.isDurable(vref) ||
+                Fail`value for ${q(prop)} is not durable at slot ${q(
+                  index,
+                )} of ${after}`;
+            });
+          }
+          vrm.updateReferenceCounts(before.slots, after.slots);
+          innerSelf.rawState[prop] = after;
+          cache.markDirty(innerSelf);
+        },
+        enumerable: true,
+        configurable: false,
+      });
+    };
+
+    harden(statePrototype);
+
     const facetiousness = assessFacetiousness(behavior);
     switch (facetiousness) {
       case 'one': {
@@ -717,37 +758,15 @@ export function makeVirtualObjectManager(
         }
       }
 
-      const state = {};
+      const state = { __proto__: statePrototype };
       if (!initializing) {
         ensureState();
       }
       for (const prop of Object.getOwnPropertyNames(innerSelf.rawState)) {
-        Object.defineProperty(state, prop, {
-          get: () => {
-            ensureState();
-            return unserializeSlot(innerSelf.rawState[prop], prop);
-          },
-          set: value => {
-            ensureState();
-            const before = innerSelf.rawState[prop];
-            const after = serializeSlot(value, prop);
-            assertAcceptableSyscallCapdataSize([after]);
-            if (isDurable) {
-              after.slots.forEach((vref, index) => {
-                vrm.isDurable(vref) ||
-                  Fail`value for ${q(prop)} is not durable at slot ${q(
-                    index,
-                  )} of ${after}`;
-              });
-            }
-            vrm.updateReferenceCounts(before.slots, after.slots);
-            innerSelf.rawState[prop] = after;
-            cache.markDirty(innerSelf);
-          },
-          enumerable: true,
-        });
+        Object.defineProperty(state, prop, makeFieldDescriptor(prop));
       }
       harden(state);
+      stateToInnerSelfMap.set(state, innerSelf);
 
       if (initializing) {
         cache.remember(innerSelf);