feat(open): add flags support

lib/api/createWriteStream.js

 var Writable = require('stream').Writable;
 
 var BigInt = require('../tools/bigint');
+var parseFlags = require('../tools/parse-flags');
 var request = require('../tools/smb2-forge').request;
-var constants = require('../structures/constants');
 
 // Where does it come from?!
 var maxPacketSize = 0x00010000 - 0x71;
@@ -13,20 +13,13 @@ module.exports = function createWriteStream(path, options, cb) {
     options = {};
   }
 
-  var createDisposition;
-  var flags = options != null && options.flags;
-  if (flags === 'r+') {
-    createDisposition = constants.FILE_OPEN;
-  } else if (flags === 'w' || flags === 'w+') {
-    createDisposition = constants.FILE_OVERWRITE_IF;
-  } else if (flags === 'wx' || flags === 'wx+') {
-    createDisposition = constants.FILE_CREATE;
-  }
-
   var connection = this;
   request(
     'create',
-    { createDisposition: createDisposition, path: path },
+    {
+      createDisposition: parseFlags((options != null && options.flags) || 'wx'),
+      path: path,
+    },
     connection,
     function(err, file) {
       if (err != null) {

lib/api/open.js

+var parseFlags = require('../tools/parse-flags');
 var request = require('../tools/smb2-forge').request;
 
-module.exports = function open(path, cb) {
-  request('open', { path: path }, this, cb);
+module.exports = function open(path, flags, cb) {
+  if (typeof flags === 'function') {
+    cb = flags;
+    flags = undefined;
+  }
+
+  request(
+    'create',
+    { createDisposition: parseFlags(flags || 'r'), path: path },
+    this,
+    cb
+  );
 };

lib/api/writeFile.js

 var SMB2Forge = require('../tools/smb2-forge');
 var SMB2Request = SMB2Forge.request;
 var BigInt = require('../tools/bigint');
-var constants = require('../structures/constants');
+var parseFlags = require('../tools/parse-flags');
 
 /*
  * writeFile
@@ -24,16 +24,6 @@ module.exports = function writeFile(filename, data, options, cb) {
     options = {};
   }
 
-  var createDisposition;
-  var flags = options != null && (options.flags || options.flag);
-  if (flags === 'r+') {
-    createDisposition = constants.FILE_OPEN;
-  } else if (flags === 'w' || flags === 'w+') {
-    createDisposition = constants.FILE_OVERWRITE_IF;
-  } else if (flags === 'wx' || flags === 'wx+') {
-    createDisposition = constants.FILE_CREATE;
-  }
-
   options.encoding = options.encoding || 'utf8';
 
   var connection = this;
@@ -46,7 +36,12 @@ module.exports = function writeFile(filename, data, options, cb) {
   function createFile(fileCreated) {
     SMB2Request(
       'create',
-      { createDisposition: createDisposition, path: filename },
+      {
+        createDisposition: parseFlags(
+          (options != null && (options.flags || options.flag)) || 'wx'
+        ),
+        path: filename,
+      },
       connection,
       function(err, f) {
         if (err) cb && cb(err);

lib/tools/parse-flags.js

+var c = require('../structures/constants');
+
+module.exports = function parseFlags(flags) {
+  const chars = { __proto__: null };
+  for (let i = 0, n = flags.length; i < n; ++i) {
+    chars[flags[i]] = true;
+  }
+
+  if ('r' in chars) {
+    return c.FILE_OPEN;
+  }
+  if ('x' in chars) {
+    return c.FILE_CREATE;
+  }
+  if ('a' in chars) {
+    return c.FILE_OPEN_IF;
+  }
+  if ('w' in chars) {
+    return c.FILE_OVERWRITE_IF;
+  }
+  throw new Error('invalid flags');
+};