bchelli/node-smb2

var SMB2Forge = require('../tools/smb2-forge')
  , SMB2Request = SMB2Forge.request
  , bigint = require('../tools/bigint')
  ;

/*
 * readFile
 * ========
 *
 * read the content of a file from the share
 *
 *  - open the file
 *
 *  - read the content
 *
 *  - close the file
 *
 */
module.exports = function(filename, options, cb){
  var connection = this;

  if(typeof options == 'function'){
    cb = options;
    options = {};
  }

  SMB2Request('open', {path:filename}, connection, function(err, file){
    if(err) cb && cb(err);
    // SMB2 read file content
    else {
      var fileLength = 0
        , offset = new bigint(8)
        , stop = false
        , nbRemainingPackets = 0
        , maxPacketSize = 0x00010000
        ;
      // get file length
      for(var i=0;i<file.EndofFile.length;i++){
        fileLength |= file.EndofFile[i] << (i*8);
      }
      var result = new Buffer(fileLength);
      // callback manager
      function callback(offset){
        return function(err, content){
          if(stop) return;
          if(err) {
            cb && cb(err);
            stop = true;
          } else {
            content.copy(result, offset.toNumber());
            nbRemainingPackets--;
            checkDone();
          }
        }
      }
      // callback manager
      function checkDone(){
        if(stop) return;
        createPackets();
        if(nbRemainingPackets==0 && offset.ge(fileLength)) {
          SMB2Request('close', file, connection, function(err){
            if(options.encoding){
              result = result.toString(options.encoding);
            }
            cb && cb(null, result);
          })
        }
      }
      // create packets
      function createPackets(){
        while(nbRemainingPackets<connection.packetConcurrency && offset.lt(fileLength)){
          // process packet size
          var rest = offset.sub(fileLength).neg();
          var packetSize = rest.gt(maxPacketSize) ? maxPacketSize : rest.toNumber();
          // generate buffer
          SMB2Request('read', {
            'FileId':file.FileId
          , 'Length':packetSize
          , 'Offset':offset.toBuffer()
          }, connection, callback(offset));
          offset = offset.add(packetSize);
          nbRemainingPackets++;
        }
      }
      checkDone();
    }
  });
}