feat: methods can return promises (#28)

Async methods return promises if no callbacks is passed.

lib/smb2.js

@@ -9,6 +9,7 @@ var shareRegExp = /\\\\([^\\]*)\\([^\\]*)\\?/,
 /*
  * DEPENDENCIES
  */
+var autoPromise = require('./tools/auto-promise');
 var SMB2Connection = require('./tools/smb2-connection');
 
 /*
@@ -80,27 +81,52 @@ var proto = (SMB.prototype = {});
 
 proto.disconnect = require('./api/disconnect');
 
-proto.exists = SMB2Connection.requireConnect(require('./api/exists'));
+proto.exists = autoPromise(
+  SMB2Connection.requireConnect(require('./api/exists'))
+);
 
-proto.rename = SMB2Connection.requireConnect(require('./api/rename'));
+proto.rename = autoPromise(
+  SMB2Connection.requireConnect(require('./api/rename'))
+);
 
-proto.readFile = SMB2Connection.requireConnect(require('./api/readfile'));
-proto.createReadStream = SMB2Connection.requireConnect(
-  require('./api/createReadStream')
+proto.readFile = autoPromise(
+  SMB2Connection.requireConnect(require('./api/readfile'))
+);
+proto.createReadStream = autoPromise(
+  SMB2Connection.requireConnect(require('./api/createReadStream'))
 );
-proto.createWriteStream = SMB2Connection.requireConnect(
-  require('./api/createWriteStream')
+proto.createWriteStream = autoPromise(
+  SMB2Connection.requireConnect(require('./api/createWriteStream'))
+);
+proto.writeFile = autoPromise(
+  SMB2Connection.requireConnect(require('./api/writefile'))
+);
+proto.unlink = autoPromise(
+  SMB2Connection.requireConnect(require('./api/unlink'))
 );
-proto.writeFile = SMB2Connection.requireConnect(require('./api/writefile'));
-proto.unlink = SMB2Connection.requireConnect(require('./api/unlink'));
 
-proto.readdir = SMB2Connection.requireConnect(require('./api/readdir'));
-proto.rmdir = SMB2Connection.requireConnect(require('./api/rmdir'));
-proto.mkdir = SMB2Connection.requireConnect(require('./api/mkdir'));
+proto.readdir = autoPromise(
+  SMB2Connection.requireConnect(require('./api/readdir'))
+);
+proto.rmdir = autoPromise(
+  SMB2Connection.requireConnect(require('./api/rmdir'))
+);
+proto.mkdir = autoPromise(
+  SMB2Connection.requireConnect(require('./api/mkdir'))
+);
 
-proto.ensureDir = SMB2Connection.requireConnect(require('./api/ensureDir'));
-proto.getSize = SMB2Connection.requireConnect(require('./api/getSize'));
+proto.ensureDir = autoPromise(
+  SMB2Connection.requireConnect(require('./api/ensureDir'))
+);
+proto.getSize = autoPromise(
+  SMB2Connection.requireConnect(require('./api/getSize'))
+);
 
-proto.open = SMB2Connection.requireConnect(require('./api/open'));
-proto.read = require('./api/read');
-proto.close = require('./api/close');
+proto.open = autoPromise(SMB2Connection.requireConnect(require('./api/open')));
+proto.read = autoPromise(require('./api/read'), function(bytesRead, buffer) {
+  return {
+    bytesRead: bytesRead,
+    buffer: buffer,
+  };
+});
+proto.close = autoPromise(require('./api/close'));

lib/tools/auto-promise.js

+var slice = Array.prototype.slice;
+
+// decorate an async function taking a callback to make it return a promise if
+// no callback is passed
+//
+// `makeResult` is optional function
+module.exports = function autoPromise(fn, makeResult) {
+  return function() {
+    var promise;
+
+    var args = arguments;
+    var n = args.length;
+    if (n !== 0 && typeof args[n - 1] !== 'function') {
+      args = slice.call(arguments);
+      promise = new Promise(function(resolve, reject) {
+        args.push(function(err, result) {
+          if (err != null) {
+            reject(err);
+          } else {
+            resolve(
+              makeResult !== undefined
+                ? makeResult.apply(this, slice.call(arguments, 1))
+                : result
+            );
+          }
+        });
+      });
+    }
+
+    fn.apply(this, args);
+
+    return promise;
+  };
+};