feat: marshal based on user's petnames (#1092)

* feat: add a petname system that hydrates and dehydrates based on petnames

packages/cosmic-swingset/lib/ag-solo/vats/lib-dehydrate.js

@@ -0,0 +1,87 @@
+import harden from '@agoric/harden';
+import { makeMarshal } from '@agoric/marshal';
+import makeStore from '@agoric/store';
+import { assert, details } from '@agoric/assert';
+
+// Marshalling for the UI should only use the user's petnames. We will
+// call marshalling for the UI "dehydration" and "hydration" to distinguish it from
+// other marshalling.
+export const makeDehydrator = (initialUnnamedCount = 0) => {
+  let unnamedCount = initialUnnamedCount;
+
+  const petnameKindToMapping = makeStore();
+
+  const searchOrder = [];
+
+  const makeMapping = kind => {
+    assert.typeof(kind, 'string', details`kind ${kind} must be a string`);
+    const valToPetname = makeStore();
+    const petnameToVal = makeStore();
+    const addPetname = (petname, val) => {
+      assert(
+        !petnameToVal.has(petname),
+        details`petname ${petname} is already in use`,
+      );
+      assert(!valToPetname.has(val), details`val ${val} already has a petname`);
+      petnameToVal.init(petname, val);
+      valToPetname.init(val, petname);
+    };
+    const mapping = harden({
+      valToPetname,
+      petnameToVal,
+      addPetname,
+      kind,
+    });
+    petnameKindToMapping.init(kind, mapping);
+    return mapping;
+  };
+
+  const unnamedMapping = makeMapping('unnamed');
+
+  const addToUnnamed = val => {
+    unnamedCount += 1;
+    const placeholder = `unnamed-${unnamedCount}`;
+    const placeholderName = harden({
+      kind: 'unnamed',
+      petname: placeholder,
+    });
+    unnamedMapping.addPetname(placeholder, val);
+    return placeholderName;
+  };
+
+  // look through the petname stores in order and create a new
+  // unnamed record if not found.
+  const convertValToName = val => {
+    for (let i = 0; i < searchOrder.length; i += 1) {
+      const kind = searchOrder[i];
+      const { valToPetname } = petnameKindToMapping.get(kind);
+      if (valToPetname.has(val)) {
+        return harden({
+          kind,
+          petname: valToPetname.get(val),
+        });
+      }
+    }
+    // not found in any map
+    const placeholderName = addToUnnamed(val);
+    return placeholderName;
+  };
+
+  const convertNameToVal = ({ kind, petname }) => {
+    const { petnameToVal } = petnameKindToMapping.get(kind);
+    return petnameToVal.get(petname);
+  };
+  const { serialize: dehydrate, unserialize: hydrate } = makeMarshal(
+    convertValToName,
+    convertNameToVal,
+  );
+  return harden({
+    hydrate,
+    dehydrate,
+    makeMapping: kind => {
+      const mapping = makeMapping(kind);
+      searchOrder.push(kind);
+      return mapping;
+    },
+  });
+};

packages/cosmic-swingset/package.json

@@ -26,6 +26,7 @@
     "@agoric/evaluate": "^2.2.5",
     "@agoric/eventual-send": "^0.9.1",
     "@agoric/harden": "^0.0.8",
+    "@agoric/marshal": "^0.2.0",
     "@agoric/nat": "2.0.1",
     "@agoric/produce-promise": "^0.1.1",
     "@agoric/registrar": "^0.1.1",

packages/cosmic-swingset/test/unitTests/test-lib-dehydrate.js

@@ -0,0 +1,191 @@
+// eslint-disable-next-line import/no-extraneous-dependencies
+import { test } from 'tape-promise/tape';
+import harden from '@agoric/harden';
+
+import { makeDehydrator } from '../../lib/ag-solo/vats/lib-dehydrate';
+
+test('makeDehydrator', async t => {
+  try {
+    const { hydrate, dehydrate, makeMapping } = makeDehydrator();
+
+    const instanceHandleMapping = makeMapping('instanceHandle');
+    const brandMapping = makeMapping('brand');
+
+    const handle1 = harden({});
+    const handle2 = harden({});
+    const handle3 = harden({});
+    instanceHandleMapping.addPetname('simpleExchange', handle1);
+    instanceHandleMapping.addPetname('atomicSwap', handle2);
+    instanceHandleMapping.addPetname('automaticRefund', handle3);
+    t.throws(
+      () => instanceHandleMapping.addPetname('simpleExchange2', handle1),
+      `cannot add a second petname for the same value`,
+    );
+    t.throws(
+      () => instanceHandleMapping.addPetname('simpleExchange', harden({})),
+      `cannot add another value for the same petname`,
+    );
+
+    const makeMockBrand = () =>
+      harden({
+        isMyIssuer: _allegedIssuer => {},
+        getAllegedName: () => {},
+      });
+
+    const brand1 = makeMockBrand();
+    const brand2 = makeMockBrand();
+    const brand3 = makeMockBrand();
+    brandMapping.addPetname('moola', brand1);
+    brandMapping.addPetname('simolean', brand2);
+    brandMapping.addPetname('zoeInvite', brand3);
+
+    t.deepEquals(
+      dehydrate(harden({ handle: handle1 })),
+      {
+        body: '{"handle":{"@qclass":"slot","index":0}}',
+        slots: [{ kind: 'instanceHandle', petname: 'simpleExchange' }],
+      },
+      `serialize val with petname`,
+    );
+    t.deepEquals(
+      hydrate(
+        harden({
+          body: '{"handle":{"@qclass":"slot","index":0}}',
+          slots: [{ kind: 'instanceHandle', petname: 'simpleExchange' }],
+        }),
+      ),
+      harden({ handle: handle1 }),
+      `deserialize val with petname`,
+    );
+    t.deepEquals(
+      dehydrate(harden({ brand: brand1, extent: 40 })),
+      harden({
+        body: '{"brand":{"@qclass":"slot","index":0},"extent":40}',
+        slots: [{ kind: 'brand', petname: 'moola' }],
+      }),
+      `serialize brand with petname`,
+    );
+    t.deepEquals(
+      hydrate(
+        harden({
+          body: '{"brand":{"@qclass":"slot","index":0},"extent":40}',
+          slots: [{ kind: 'brand', petname: 'moola' }],
+        }),
+      ),
+      harden({ brand: brand1, extent: 40 }),
+      `deserialize brand with petname`,
+    );
+    const proposal = harden({
+      want: {
+        Asset1: { brand: brand1, extent: 60 },
+        Asset2: { brand: brand3, extent: { instanceHandle: handle3 } },
+      },
+      give: {
+        Price: { brand: brand2, extent: 3 },
+      },
+      exit: {
+        afterDeadline: {
+          timer: {},
+          deadline: 55,
+        },
+      },
+    });
+    t.deepEquals(
+      dehydrate(proposal),
+      {
+        body:
+          '{"want":{"Asset1":{"brand":{"@qclass":"slot","index":0},"extent":60},"Asset2":{"brand":{"@qclass":"slot","index":1},"extent":{"instanceHandle":{"@qclass":"slot","index":2}}}},"give":{"Price":{"brand":{"@qclass":"slot","index":3},"extent":3}},"exit":{"afterDeadline":{"timer":{"@qclass":"slot","index":4},"deadline":55}}}',
+        slots: [
+          { kind: 'brand', petname: 'moola' },
+          { kind: 'brand', petname: 'zoeInvite' },
+          { kind: 'instanceHandle', petname: 'automaticRefund' },
+          { kind: 'brand', petname: 'simolean' },
+          { kind: 'unnamed', petname: 'unnamed-1' },
+        ],
+      },
+      `dehydrated proposal`,
+    );
+    t.deepEquals(
+      hydrate(
+        harden({
+          body:
+            '{"want":{"Asset1":{"brand":{"@qclass":"slot","index":0},"extent":60},"Asset2":{"brand":{"@qclass":"slot","index":1},"extent":{"instanceHandle":{"@qclass":"slot","index":2}}}},"give":{"Price":{"brand":{"@qclass":"slot","index":3},"extent":3}},"exit":{"afterDeadline":{"timer":{"@qclass":"slot","index":4},"deadline":55}}}',
+          slots: [
+            { kind: 'brand', petname: 'moola' },
+            { kind: 'brand', petname: 'zoeInvite' },
+            { kind: 'instanceHandle', petname: 'automaticRefund' },
+            { kind: 'brand', petname: 'simolean' },
+            { kind: 'unnamed', petname: 'unnamed-1' },
+          ],
+        }),
+      ),
+      proposal,
+      `hydrated proposal`,
+    );
+    const handle4 = harden({});
+    t.deepEquals(
+      dehydrate(harden({ handle: handle4 })),
+      {
+        body: '{"handle":{"@qclass":"slot","index":0}}',
+        slots: [{ kind: 'unnamed', petname: 'unnamed-2' }],
+      },
+      `serialize val with no petname`,
+    );
+    t.deepEquals(
+      hydrate(
+        harden({
+          body: '{"handle":{"@qclass":"slot","index":0}}',
+          slots: [{ kind: 'unnamed', petname: 'unnamed-2' }],
+        }),
+      ),
+      { handle: handle4 },
+      `deserialize same val with no petname`,
+    );
+    // Name a previously unnamed handle
+    instanceHandleMapping.addPetname('autoswap', handle4);
+    t.deepEquals(
+      dehydrate(harden({ handle: handle4 })),
+      {
+        body: '{"handle":{"@qclass":"slot","index":0}}',
+        slots: [{ kind: 'instanceHandle', petname: 'autoswap' }],
+      },
+      `serialize val with new petname`,
+    );
+    t.deepEquals(
+      hydrate(
+        harden({
+          body: '{"handle":{"@qclass":"slot","index":0}}',
+          slots: [{ kind: 'instanceHandle', petname: 'autoswap' }],
+        }),
+      ),
+      { handle: handle4 },
+      `deserialize same val with new petname`,
+    );
+
+    // Test spoofing
+    t.notDeepEqual(
+      hydrate(
+        harden({
+          body: '{"handle":{"kind":"instanceHandle","petname":"autoswap"}}',
+          slots: [],
+        }),
+      ),
+      { handle: handle4 },
+      `deserialize with no slots does not produce the real object`,
+    );
+    t.deepEquals(
+      hydrate(
+        harden({
+          body: '{"handle":{"kind":"instanceHandle","petname":"autoswap"}}',
+          slots: [],
+        }),
+      ),
+      { handle: { kind: 'instanceHandle', petname: 'autoswap' } },
+      `deserialize with no slots does not produce the real object`,
+    );
+  } catch (e) {
+    t.isNot(e, e, 'unexpected exception');
+  } finally {
+    t.end();
+  }
+});