extract mock-gc.js out from test-liveslots.js

This utility creates manually-controlled GC utilities: WeakRef and FinalizationRegistry
Agoric · Mar 11, 2023 · 7e74cfd · 7e74cfd
1 parent f2ebdb5
commit 7e74cfd
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diff --git a/packages/swingset-liveslots/test/mock-gc.js b/packages/swingset-liveslots/test/mock-gc.js
@@ -0,0 +1,104 @@
+import { waitUntilQuiescent } from './waitUntilQuiescent.js';
+import { makeDummyMeterControl } from './dummyMeterControl.js';
+
+// Create a WeakRef/FinalizationRegistry pair that can be manipulated for
+// tests. Limitations:
+// * only one WeakRef per object
+// * no deregister
+// * extra debugging properties like FR.countCallbacks and FR.runOneCallback
+// * nothing is hardened
+
+export function makeMockGC() {
+  const weakRefToVal = new Map();
+  const valToWeakRef = new Map();
+  const allFRs = [];
+  // eslint-disable-next-line no-unused-vars
+  function log(...args) {
+    // console.log(...args);
+  }
+
+  const mockWeakRefProto = {
+    deref() {
+      return weakRefToVal.get(this);
+    },
+  };
+  function mockWeakRef(val) {
+    assert(!valToWeakRef.has(val));
+    weakRefToVal.set(this, val);
+    valToWeakRef.set(val, this);
+  }
+  mockWeakRef.prototype = mockWeakRefProto;
+
+  function kill(val) {
+    log(`kill`, val);
+    if (valToWeakRef.has(val)) {
+      log(` killing weakref`);
+      const wr = valToWeakRef.get(val);
+      valToWeakRef.delete(val);
+      weakRefToVal.delete(wr);
+    }
+    for (const fr of allFRs) {
+      if (fr.registry.has(val)) {
+        log(` pushed on FR queue, context=`, fr.registry.get(val));
+        fr.ready.push(val);
+      }
+    }
+    log(` kill done`);
+  }
+
+  const mockFinalizationRegistryProto = {
+    register(val, context) {
+      log(`FR.register(context=${context})`);
+      this.registry.set(val, context);
+    },
+    countCallbacks() {
+      log(`countCallbacks:`);
+      log(` ready:`, this.ready);
+      log(` registry:`, this.registry);
+      return this.ready.length;
+    },
+    runOneCallback() {
+      log(`runOneCallback`);
+      const val = this.ready.shift();
+      log(` val:`, val);
+      assert(this.registry.has(val));
+      const context = this.registry.get(val);
+      log(` context:`, context);
+      this.registry.delete(val);
+      this.callback(context);
+    },
+    flush() {
+      while (this.ready.length) {
+        this.runOneCallback();
+      }
+    },
+  };
+
+  function mockFinalizationRegistry(callback) {
+    this.registry = new Map();
+    this.callback = callback;
+    this.ready = [];
+    allFRs.push(this);
+  }
+  mockFinalizationRegistry.prototype = mockFinalizationRegistryProto;
+
+  function getAllFRs() {
+    return allFRs;
+  }
+  function flushAllFRs() {
+    allFRs.map(fr => fr.flush());
+  }
+
+  function mockGCAndFinalize() {}
+
+  return harden({
+    WeakRef: mockWeakRef,
+    FinalizationRegistry: mockFinalizationRegistry,
+    kill,
+    getAllFRs,
+    flushAllFRs,
+    waitUntilQuiescent,
+    gcAndFinalize: mockGCAndFinalize,
+    meterControl: makeDummyMeterControl(),
+  });
+}
diff --git a/packages/swingset-liveslots/test/test-liveslots.js b/packages/swingset-liveslots/test/test-liveslots.js
@@ -5,11 +5,9 @@ import '@endo/init/debug.js';
 import { E } from '@endo/eventual-send';
 import { Far } from '@endo/marshal';
 import { makePromiseKit } from '@endo/promise-kit';
-import { assert, Fail } from '@agoric/assert';
+import { Fail } from '@agoric/assert';
 import engineGC from './engine-gc.js';
-import { waitUntilQuiescent } from './waitUntilQuiescent.js';
 import { makeGcAndFinalize } from './gc-and-finalize.js';
-import { makeDummyMeterControl } from './dummyMeterControl.js';
 import { makeLiveSlots, makeMarshaller } from '../src/liveslots.js';
 import { kslot, kser, kunser } from './kmarshal.js';
 import { buildSyscall, makeDispatch } from './liveslots-helpers.js';
@@ -23,6 +21,7 @@ import {
   makeRetireExports,
   makeRetireImports,
 } from './util.js';
+import { makeMockGC } from './mock-gc.js';
 
 function matchIDCounterSet(t, log) {
   t.like(log.shift(), { type: 'vatstoreSet', key: 'idCounters' });
@@ -1201,99 +1200,6 @@ test('GC dispatch.retireExports', async t => {
   t.deepEqual(log, []);
 });
 
-// Create a WeakRef/FinalizationRegistry pair that can be manipulated for
-// tests. Limitations:
-// * only one WeakRef per object
-// * no deregister
-// * extra debugging properties like FR.countCallbacks and FR.runOneCallback
-// * nothing is hardened
-
-function makeMockGC() {
-  const weakRefToVal = new Map();
-  const valToWeakRef = new Map();
-  const allFRs = [];
-  // eslint-disable-next-line no-unused-vars
-  function log(...args) {
-    // console.log(...args);
-  }
-
-  const mockWeakRefProto = {
-    deref() {
-      return weakRefToVal.get(this);
-    },
-  };
-  function mockWeakRef(val) {
-    assert(!valToWeakRef.has(val));
-    weakRefToVal.set(this, val);
-    valToWeakRef.set(val, this);
-  }
-  mockWeakRef.prototype = mockWeakRefProto;
-
-  function kill(val) {
-    log(`kill`, val);
-    if (valToWeakRef.has(val)) {
-      log(` killing weakref`);
-      const wr = valToWeakRef.get(val);
-      valToWeakRef.delete(val);
-      weakRefToVal.delete(wr);
-    }
-    for (const fr of allFRs) {
-      if (fr.registry.has(val)) {
-        log(` pushed on FR queue, context=`, fr.registry.get(val));
-        fr.ready.push(val);
-      }
-    }
-    log(` kill done`);
-  }
-
-  const mockFinalizationRegistryProto = {
-    register(val, context) {
-      log(`FR.register(context=${context})`);
-      this.registry.set(val, context);
-    },
-    countCallbacks() {
-      log(`countCallbacks:`);
-      log(` ready:`, this.ready);
-      log(` registry:`, this.registry);
-      return this.ready.length;
-    },
-    runOneCallback() {
-      log(`runOneCallback`);
-      const val = this.ready.shift();
-      log(` val:`, val);
-      assert(this.registry.has(val));
-      const context = this.registry.get(val);
-      log(` context:`, context);
-      this.registry.delete(val);
-      this.callback(context);
-    },
-  };
-
-  function mockFinalizationRegistry(callback) {
-    this.registry = new Map();
-    this.callback = callback;
-    this.ready = [];
-    allFRs.push(this);
-  }
-  mockFinalizationRegistry.prototype = mockFinalizationRegistryProto;
-
-  function getAllFRs() {
-    return allFRs;
-  }
-
-  function mockGCAndFinalize() {}
-
-  return harden({
-    WeakRef: mockWeakRef,
-    FinalizationRegistry: mockFinalizationRegistry,
-    kill,
-    getAllFRs,
-    waitUntilQuiescent,
-    gcAndFinalize: mockGCAndFinalize,
-    meterControl: makeDummyMeterControl(),
-  });
-}
-
 test('dropImports', async t => {
   const { syscall } = buildSyscall();
   const imports = [];