check and auto-install if llvm-cov is not available

src/deps.ts

@@ -0,0 +1,50 @@
+import * as core from "@actions/core";
+import * as exec from "@actions/exec";
+import * as io from "@actions/io";
+import * as os from "os";
+
+async function isAvailable(tool: string): Promise<boolean> {
+  try {
+    await io.which(tool, true);
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+async function chocoInstall(pkg: string) {
+  await exec.exec("choco", ["install", "-y", pkg]);
+}
+
+async function aptInstall(pkg: string) {
+  await exec.exec("sudo", ["apt-get", "install", "-y", pkg]);
+}
+
+async function brewInstall(pkg: string) {
+  await exec.exec("brew", ["install", pkg]);
+}
+
+async function smartInstall(pkg: string) {
+  switch (os.type()) {
+    case "Windows_NT":
+      chocoInstall(pkg);
+      break;
+    case "Linux":
+      aptInstall(pkg);
+      break;
+    case "Darwin":
+      brewInstall(pkg);
+      break;
+    default:
+      throw new Error(`unknown OS type: ${os.type()}`);
+  }
+}
+
+export async function checkLlvm() {
+  const available = await isAvailable("llvm-cov");
+  if (!available) {
+    await core.group("Install LLVM", async () => {
+      await smartInstall("llvm");
+    });
+  }
+}

src/main.ts

@@ -1,11 +1,18 @@
 import * as core from "@actions/core";
 import * as action from "./action";
+import * as deps from "./deps";
 import * as gcovr from "./gcovr";
 
 async function run(): Promise<void> {
   try {
     const inputs = action.parseInputs();
     await gcovr.check();
+    if (
+      inputs.gcovExecutable !== null &&
+      inputs.gcovExecutable.includes("llvm-cov")
+    ) {
+      deps.checkLlvm();
+    }
     await gcovr.run(inputs);
   } catch (error) {
     if (error instanceof Error) core.setFailed(error.message);