feat(ENG-653): add method getTotatlConstraints to allow get total constraints of the circuit

Author: Harsh Bajpai

src/circuit.ts

@@ -7,6 +7,7 @@ import {CircuitConfig, Networks, Witness, ZK_PROOF} from "./types";
 import {genGrothZKey, genPlonkZKey, genVerificationKey} from "./utils/zKey";
 import {genGroth16Proof, genPlonkProof, verifyGroth16Proof, verifyPlonkProof} from "./utils/proof";
 import * as fs from "fs";
+import {getTotalConstraints} from "./utils/r1cs";
 
 export class Circuit {
     private _circuitConfig: CircuitConfig;
@@ -46,6 +47,14 @@ export class Circuit {
         return this._wasmTester.checkConstraints(w)
     }
 
+    async getTotalConstraints(): Promise<number>{
+        if(!fs.existsSync(this._circuitConfig.r1csPath)){
+            await this.compile()
+        }
+
+        return getTotalConstraints(this._circuitConfig.r1csPath)
+    }
+
     private _genZKey() {
         log.info("generating zKey, ckt:%s, pTau:%s, zKey:%s",
             this._circuitConfig.cktName,

src/configParser.ts

@@ -144,6 +144,7 @@ export class ConfigParser {
         wasmPath: path.join(cktOutputDir, `${cktName}_js`, `${cktName}.wasm`),
         zKeyPath: path.join(cktOutputDir, "circuit_final.zkey"), // DO NOT change the names
         vKeyPath: path.join(cktOutputDir, "verification_key.json"), // DO NOT change the names
+        r1csPath: path.join(cktOutputDir, `${cktName}.r1cs`),
         compileOptions: {
           include: [],
           snarkType: c.proofType ? c.proofType : "groth16",

src/types.ts

@@ -64,7 +64,8 @@ export type CircuitConfig = {
     wasmPath: string;
     zKeyPath: string;
     vKeyPath: string;
-    compileOptions: CompileOptions
+    compileOptions: CompileOptions;
+    r1csPath:string
 }
 
 export type CompileOptions = {
@@ -78,3 +79,7 @@ export type CompileOptions = {
     O: number;
     verbose: boolean;
 }
+
+export type R1CSInfo = {
+
+}

src/utils/index.ts

@@ -1,2 +1,3 @@
 export * as cfg from '../configParser'
-export * as proof from './proof'
+export * as proof from './proof'
+export * as r1cs from "./r1cs"

src/utils/r1cs.ts

@@ -0,0 +1,13 @@
+const {r1cs} = require("snarkjs")
+const {info} = r1cs
+
+
+// TODO: provide typescript type for the return type
+const getR1CSInfo = async(r1csFilePath:string) => {
+    return await info(r1csFilePath)
+}
+
+export const getTotalConstraints = async (r1csFilePath: string): Promise<number> => {
+    const {nConstraints} =  await getR1CSInfo(r1csFilePath)
+    return nConstraints
+}

tests/circuit.test.ts

@@ -121,6 +121,15 @@ describe("Circuit test", () => {
     expect(verificationRes).toBe(true);
   }, 30000);
 
+  it("should calculate total constraints in a circuit", async () => {
+    const c = new CircomJS(testConfigPath);
+    const n1 =await c.getCircuit("mul").getTotalConstraints()
+    const n1000 =await c.getCircuit("circ1000constraints").getTotalConstraints()
+
+    expect(n1).toEqual(1)
+    expect(n1000).toEqual(1001)
+  })
+
   afterAll(() => {
     fs.rmSync(testConfigPath);
   });