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jfparadisjfparadis
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feat(exchange-vat): Reduce the number of round-trips (#112)
* feat(exchange-vat): Reduce the number of round-trips in getPrice() * feat(exchange-vat): Reduce the number of round-trips in getOfferRules()
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‎lib/ag-solo/vats/lib-exchange.js

+84-89
Original file line numberDiff line numberDiff line change
@@ -12,99 +12,94 @@ function checkOrder(a0, a1, b0, b1) {
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throw new TypeError('Canot resove asset ordering');
1313
}
1414

15-
export async function makeExchange(E, log, host, zoe, registrar) {
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// === API
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async function getPrice(instanceId, extent0, assayId0, assayId1) {
19-
const instanceHandle = await E(registrar).get(instanceId);
20-
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// Find the assays in the registrar
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const registrarAssays = await Promise.all([
23-
E(registrar).get(assayId0),
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E(registrar).get(assayId1),
25-
]);
26-
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// Get the assays in the contract.
28-
// Get the contract instance.
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const {
30-
terms: { assays: contractAssays },
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instance,
32-
} = await E(zoe).getInstance(instanceHandle);
33-
34-
// Check whether we sell on contract assay 0 or 1.
35-
const normal = checkOrder(
36-
registrarAssays[0],
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registrarAssays[1],
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contractAssays[0],
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contractAssays[1],
15+
export function makeExchange(E, log, host, zoe, registrar) {
16+
17+
function getPrice(instanceId, extent0, assayId0, assayId1) {
18+
const instanceHandleP = E(registrar).get(instanceId);
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const regAssay0P = E(registrar).get(assayId0);
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const regAssay1P = E(registrar).get(assayId1);
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const unit0P = E(regAssay0P).makeUnits(extent0);
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return Promise.all([instanceHandleP, regAssay0P, regAssay1P, unit0P]).then(
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([instanceHandle, regAssay0, regAssay1, unit0]) =>
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E(zoe)
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.getInstance(instanceHandle)
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.then(
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({
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terms: {
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assays: [contractAssay0, contractAssay1],
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},
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instance,
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}) => {
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// Check whether we sell on contract assay 0 or 1.
35+
const normal = checkOrder(
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regAssay0,
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regAssay1,
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contractAssay0,
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contractAssay1,
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);
41+
// Order the units accordingly.
42+
const units = [
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normal ? unit0 : undefined,
44+
normal ? undefined : unit0,
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undefined,
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];
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return E(instance)
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.getPrice(units)
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.then(unit1 => unit1.extent);
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},
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),
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);
41-
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// Units of the input amount.
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const unit0 = await E(registrarAssays[0]).makeUnits(extent0);
44-
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// Order the units accordingly.
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const units = [
47-
normal ? unit0 : undefined,
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normal ? undefined : unit0,
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undefined,
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];
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// Extract the price (multi steps for debugging).
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const unit1 = await E(instance).getPrice(units);
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const { extent } = unit1;
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return extent;
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}
5754

58-
async function getOfferRules(instanceId, extent, assayId0, assayId1) {
59-
const instanceHandle = await E(registrar).get(instanceId);
60-
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// Find the assays by id in the registrar.
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const registrarAssays = await Promise.all([
63-
E(registrar).get(assayId0),
64-
E(registrar).get(assayId1),
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]);
66-
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// Get the assays in the contract.
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const {
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terms: { assays: contractAssays },
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} = await E(zoe).getInstance(instanceHandle);
71-
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// Check whether we sell on contract assay 0 or 1.
73-
const normal = checkOrder(
74-
registrarAssays[0],
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registrarAssays[1],
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contractAssays[0],
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contractAssays[1],
55+
function getOfferRules(instanceId, extent0, assayId0, assayId1) {
56+
const instanceHandleP = E(registrar).get(instanceId);
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const regAssay0P = E(registrar).get(assayId0);
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const regAssay1P = E(registrar).get(assayId1);
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return Promise.all([instanceHandleP, regAssay0P, regAssay1P]).then(
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([instanceHandle, regAssay0, regAssay1]) =>
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E(zoe)
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.getInstance(instanceHandle)
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.then(({ terms: { assays: [contractAssay0, contractAssay1] } }) => {
65+
// Check whether we sell on contract assay 0 or 1.
66+
const normal = checkOrder(
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regAssay0,
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regAssay1,
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contractAssay0,
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contractAssay1,
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);
72+
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// Contrust the rules for serialization (no instance).
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// This rule is the payment
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const rule0 = {
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kind: 'offerExactly',
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units: { assayId: assayId0, extent: extent0 },
78+
};
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// This rule is the payout
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const rule1 = {
81+
kind: 'wantAtLeast',
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units: { assayId: assayId1 },
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};
84+
85+
// Order the rules accordingly.
86+
const offerRules = harden({
87+
payoutRules: [
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normal ? rule0 : rule1,
89+
normal ? rule1 : rule0,
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{
91+
kind: 'wantAtLeast',
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units: {},
93+
},
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],
95+
exitRule: {
96+
kind: 'onDemand',
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},
98+
});
99+
100+
return offerRules;
101+
}),
78102
);
79-
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// Contrust the rules for serialization (no instance).
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// This rule is the payment
82-
const rule0 = {
83-
kind: 'offerExactly',
84-
units: { assayId: assayId0, extent },
85-
};
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// This rule is the payout
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const rule1 = {
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kind: 'wantAtLeast',
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units: { assayId: assayId1 },
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};
91-
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// Order the rules accordingly.
93-
const offerRules = harden({
94-
payoutRules: [
95-
normal ? rule0 : rule1,
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normal ? rule1 : rule0,
97-
{
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kind: 'wantAtLeast',
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units: {},
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},
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],
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exitRule: {
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kind: 'onDemand',
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},
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});
106-
107-
return offerRules;
108103
}
109104

110105
const autoswap = harden({

‎lib/ag-solo/vats/vat-exchange.js

+3-3
Original file line numberDiff line numberDiff line change
@@ -4,12 +4,12 @@ import { makeExchange } from './lib-exchange';
44
function build(E, log) {
55
let userFacet;
66

7-
async function startup(host, zoe, registrar, uploads) {
8-
const exchange = await makeExchange(E, log, host, zoe, registrar, uploads);
7+
function startup(host, zoe, registrar, uploads) {
8+
const exchange = makeExchange(E, log, host, zoe, registrar, uploads);
99
userFacet = exchange.userFacet;
1010
}
1111

12-
async function getExchange() {
12+
function getExchange() {
1313
return harden(userFacet);
1414
}
1515

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