feat(write): low level write method

lib/api/createWriteStream.js

@@ -4,9 +4,6 @@ var BigInt = require('../tools/bigint');
 var parseFlags = require('../tools/parse-flags');
 var request = require('../tools/smb2-forge').request;
 
-// Where does it come from?!
-var maxPacketSize = 0x00010000 - 0x71;
-
 module.exports = function createWriteStream(path, options, cb) {
   if (typeof options === 'function') {
     cb = options;
@@ -31,7 +28,7 @@ module.exports = function createWriteStream(path, options, cb) {
       var close = request.bind(undefined, 'close', file, connection);
 
       function write(buffer, i, cb) {
-        var j = i + maxPacketSize;
+        var j = i + constants.MAX_WRITE_LENGTH;
         var chunk = buffer.slice(i, j);
         request(
           'write',

lib/api/write.js

+var assert = require('assert');
+
+var BigInt = require('../tools/bigint');
+var request = require('../tools/smb2-forge').request;
+var MAX_WRITE_LENGTH = require('../structures/constants').MAX_WRITE_LENGTH;
+
+module.exports = function write(file, buffer, offset, length, start, cb) {
+  assert(Buffer.isBuffer(buffer));
+  if (offset === undefined) {
+    offset = 0;
+  } else {
+    assert(typeof offset === 'number');
+    assert(offset > 0);
+    assert(offset < buffer.length);
+  }
+  if (length === undefined) {
+    length = buffer.length - offset;
+  } else {
+    assert(typeof length === 'number');
+    assert(length > 0);
+    length = Math.min(length, buffer.length - offset);
+  }
+  assert(typeof start === 'number');
+
+  var connection = this;
+  var pos = start;
+  var chunkLength;
+
+  function onWrite(err) {
+    if (err != null) {
+      return cb(err, pos - start, buffer);
+    }
+
+    offset += chunkLength;
+    pos += chunkLength;
+
+    writeChunk();
+  }
+  function writeChunk() {
+    if (length <= 0) {
+      cb(null, length);
+    }
+
+    chunkLength = Math.min(MAX_WRITE_LENGTH, length);
+    request(
+      'write',
+      {
+        Buffer: buffer.slice(offset, offset + chunkLength),
+        FileId: file.FileId,
+        Offset: new BigInt(8, pos).toBuffer(),
+      },
+      connection,
+      onWrite
+    );
+  }
+
+  process.nextTick(writeChunk);
+};

lib/api/writeFile.js

@@ -84,7 +84,7 @@ module.exports = function writeFile(filename, data, options, cb) {
     var offset = new BigInt(8);
     var stop = false;
     var nbRemainingPackets = 0;
-    var maxPacketSize = new BigInt(8, 0x00010000 - 0x71);
+    var maxPacketSize = new BigInt(8, constants.MAX_WRITE_LENGTH);
     // callback manager
     function callback() {
       return function(err) {

lib/structures/constants.js

@@ -10,6 +10,7 @@ module.exports = {
   FILE_OVERWRITE: 0x00000004,
   FILE_OVERWRITE_IF: 0x00000005,
 
-  // Where does it come from?!
+  // Where do they come from?!
   MAX_READ_LENGTH: 0x00010000,
+  MAX_WRITE_LENGTH: 0x00010000 - 0x71,
 };