Support custom path-mapped dependencies

cli.js

@@ -30,6 +30,8 @@ const compiler = require("./src/compiler");
 
 const version = require("./package").version;
 
+const parsePathMap = require("./utils/parse_path_map");
+
 const argv = require("yargs")
     .version(version)
     .usage("circom [input source circuit file] -r [output r1cs file] -c [output c file] -w [output wasm file] -t [output wat file] -s [output sym file]")
@@ -43,6 +45,11 @@ const argv = require("yargs")
     .alias("n", "newThreadTemplates")
     .help("h")
     .alias("h", "help")
+    .option("path-map", {
+        alias: "a",
+        type: "array",
+        description: "Allow a given path for imports. A list of paths can be supplied by separating them with a comma."
+    })
     .option("verbose", {
         alias: "v",
         type: "boolean",
@@ -80,10 +87,12 @@ async function run() {
     const r1csName = typeof(argv.r1cs) === "string" ?  argv.r1cs : fileName + ".r1cs";
     const symName = typeof(argv.sym) === "string" ?  argv.sym : fileName + ".sym";
 
+
     const options = {};
     options.reduceConstraints = !argv.fast;
     options.verbose = argv.verbose || false;
     options.sanityCheck = argv.sanitycheck;
+    options.pathMap = {};
 
     if (argv.csource) {
         options.cSourceFileName = cSourceName;
@@ -115,6 +124,9 @@ async function run() {
         options.prime = Scalar.fromString(argv.prime);
     }
 
+    if (argv.pathMap) {
+      options.pathMap = parsePathMap(argv.pathMap);
+    }
 
     await compiler(fullFileName, options);
 

src/compiler.js

@@ -66,6 +66,7 @@ async function compile(srcFile, options) {
     ctx.verbose= options.verbose || false;
     ctx.mainComponent = options.mainComponent || "main";
     ctx.newThreadTemplates = options.newThreadTemplates;
+    ctx.pathMap = options.pathMap;
 
     measures.constructionPhase = -performance.now();
     constructionPhase(ctx, srcFile);

src/construction_phase.js

@@ -1067,7 +1067,19 @@ function createRefs(ctx, ast, scope) {
         } else if (ast.type == "FUNCTIONDEF") {
             ast.refId = define(ast.name, {t: "F"});
         } else if (ast.type == "INCLUDE") {
-            const incFileName = path.resolve(ctx.filePath, ast.file);
+            const match = ast.file.match(/@(.+)\//);
+            let incFileName;
+            if (match) {
+              const key = match[1];
+              if (ctx.pathMap[key] == undefined) {
+                return ctx.throwError(ast, "Included path-mapped file not found:" + ast.file);
+              }
+              const val = ctx.pathMap[key];
+              incFileName = path.resolve(ast.file.replace("@" + key, val));
+            } else {
+              incFileName = path.resolve(ctx.filePath, ast.file);
+            }
+
             const incFilePath = path.dirname(incFileName);
 
             ctx.includedFiles = ctx.includedFiles || [];

test/circuits/pathMap.circom

@@ -0,0 +1,10 @@
+include "@customlib/pathMapDep.circom";
+
+template Foo() {
+    signal input in;
+    component bar = Bar();
+
+    bar.in <== in;
+}
+
+component main = Foo();

test/circuits/pathMapDep.circom

@@ -0,0 +1,6 @@
+template Bar() {
+    signal input in;
+    signal output out;
+
+    out <== in;
+}

test/compiler.js

@@ -0,0 +1,21 @@
+const path = require("path");
+const fs = require("fs");
+const shelljs = require("shelljs");
+const expect = require("chai").expect;
+
+describe("compiler tests", function () {
+    this.timeout(100000);
+
+    it('should import a path-mapped dependency', function() {
+      const r1csFile = "test." + Date.now().toString() + ".r1cs";
+      if (fs.existsSync(r1csFile)) {
+        console.error("Please delete " + r1csFile + " before running this test");
+        return;
+      }
+      const cliPath = path.join(__dirname, "..", "cli.js");
+      const cmd = "node " + cliPath + " ./test/circuits/pathMap.circom -a @customlib=./test/circuits/ -r " + r1csFile;
+      shelljs.exec(cmd);
+      expect(fs.existsSync(r1csFile)).to.equal(true);
+      fs.unlinkSync(r1csFile);
+    });
+});

utils/parse_path_map.js

@@ -0,0 +1,23 @@
+module.exports = parsePathMap;
+
+function parsePathMap(pathMap) {
+  const result = {};
+  const regex = /@(.+)=(.+)/
+  for (let i = 0; i < pathMap.length; i ++) {
+    const match = pathMap[i].match(regex);
+    if (!match) {
+        console.log("Invalid --path-map / -a value. Its format should be @alias=path.");
+        process.exit(1);
+    }
+    const alias = match[1];
+    const path = match[2];
+
+    if (Object.keys(result).indexOf(alias) !== -1) {
+        console.log("Duplicate --path-map / -a value.");
+        process.exit(1);
+    }
+
+    result[alias] = path;
+  }
+  return result;
+}