spec: use SPEC interface

spec.ts

@@ -1,4 +1,7 @@
 import * as path from 'path';
+import * as fs from "fs";
+import { promisify } from "util";
+import { SW_AUTOVEC } from "./environment";
 
 export interface SPECBench {
     objectNames: string[];
@@ -356,3 +359,40 @@ export function setenv(specdir: string): void {
     process.env.SPEC = specdir;
     process.env.PATH = `${path.join(specdir, 'bin')}${path.delimiter}${process.env.PATH}`;
 }
+
+export interface SPEC {
+    newConfig: (name: string, content: string) => Promise<void>;
+    benchpath: (bench: SPECBench) => string;
+    exepath: (bench: SPECBench) => string;
+    buildpath: (bench: SPECBench) => string;
+    setenv: () => void;
+}
+
+export function mkSPEC(specRoot: string): SPEC {
+    return {
+        newConfig: async (name: string, content: string) => {
+            await writeFile(path.join(specRoot, "config", name), content);
+        },
+        benchpath: bench => benchpath(specRoot, bench),
+        exepath: bench => exepath(specRoot, bench),
+        buildpath: bench => buildpath(specRoot, bench),
+        setenv: () => setenv(specRoot),
+    };
+}
+
+export const defaultSPEC = mkSPEC(path.join(SW_AUTOVEC, "spec2017"));
+
+const specTemplate = fs.readFileSync("assets/specTemplate.cfg").toString("utf-8");
+
+const writeFile = promisify(fs.writeFile);
+
+interface ConfigOptions {
+    gccdir: string;
+    optimize: string;
+}
+
+export function renderConfig(options: ConfigOptions) {
+    return `# Rendered from TypeScript, do not edit!\n\n\n` + specTemplate
+        .replace("@@GCCDIR@@", options.gccdir)
+        .replace("@@OPTIMIZE@@", options.optimize);
+}