fs/co: add fs.exists and wait for promise on co.clearInterval.

lib/utils/co.js

@@ -208,7 +208,9 @@ async function every(jobs) {
 function startInterval(func, time, self) {
   const ctx = {
     timer: null,
-    stopped: false
+    stopped: false,
+    running: false,
+    resolve: null
   };
 
   const cb = async () => {
@@ -216,10 +218,14 @@ function startInterval(func, time, self) {
     ctx.timer = null;
 
     try {
+      ctx.running = true;
       await func.call(self);
     } finally {
+      ctx.running = false;
       if (!ctx.stopped)
         ctx.timer = setTimeout(cb, time);
+      else if (ctx.resolve)
+        ctx.resolve();
     }
   };
 
@@ -235,11 +241,21 @@ function startInterval(func, time, self) {
 
 function stopInterval(ctx) {
   assert(ctx);
+
   if (ctx.timer != null) {
     clearTimeout(ctx.timer);
     ctx.timer = null;
   }
+
   ctx.stopped = true;
+
+  if (ctx.running) {
+    return new Promise((r) => {
+      ctx.resolve = r;
+    });
+  }
+
+  return Promise.resolve();
 }
 
 /**

lib/utils/fs.js

@@ -22,8 +22,26 @@ exports.closeSync = fs.closeSync;
 exports.constants = fs.constants;
 exports.createReadStream = fs.createReadStream;
 exports.createWriteStream = fs.createWriteStream;
-exports.exists = co.promisify(fs.exists);
-exports.existsSync = fs.existsSync;
+exports.exists = async (file) => {
+  try {
+    await exports.stat(file);
+    return true;
+  } catch (e) {
+    if (e.code === 'ENOENT')
+      return false;
+    throw e;
+  }
+};
+exports.existsSync = (file) => {
+  try {
+    exports.statSync(file);
+    return true;
+  } catch (e) {
+    if (e.code === 'ENOENT')
+      return false;
+    throw e;
+  }
+};
 exports.fchmod = co.promisify(fs.fchmod);
 exports.fchmodSync = fs.fchmodSync;
 exports.fchown = co.promisify(fs.fchown);