src/kits/shared/AttributeUtilities.cpp

   1 /*
   2  * Copyright 2005-2009, Ingo Weinhold, ingo_weinhold@gmx.de.
   3  * Copyright 2016, Axel Dörfler, axeld@pinc-software.de.
   4  * Distributed under the terms of the MIT License.
   5  */
   6
   7
   8 #include "AttributeUtilities.h"
   9
  10 #include <fs_attr.h>
  11 #include <Node.h>
  12 #include <StorageDefs.h>
  13
  14
  15 static const int kCopyBufferSize = 64 * 1024;
  16         // 64 KB
  17
  18
  19 namespace BPrivate {
  20
  21
  22 status_t
  23 CopyAttributes(BNode& source, BNode& destination)
  24 {
  25         char attrName[B_ATTR_NAME_LENGTH];
  26         while (source.GetNextAttrName(attrName) == B_OK) {
  27                 // get attr info
  28                 attr_info attrInfo;
  29                 status_t status = source.GetAttrInfo(attrName, &attrInfo);
  30                 if (status != B_OK)
  31                         return status;
  32
  33                 // copy the attribute
  34                 char buffer[kCopyBufferSize];
  35                 off_t offset = 0;
  36                 off_t bytesLeft = attrInfo.size;
  37
  38                 // Go at least once through the loop, so that an empty attribute will be
  39                 // created as well
  40                 do {
  41                         size_t toRead = kCopyBufferSize;
  42                         if ((off_t)toRead > bytesLeft)
  43                                 toRead = bytesLeft;
  44
  45                         // read
  46                         ssize_t bytesRead = source.ReadAttr(attrName, attrInfo.type,
  47                                 offset, buffer, toRead);
  48                         if (bytesRead < 0)
  49                                 return bytesRead;
  50
  51                         // write
  52                         ssize_t bytesWritten = destination.WriteAttr(attrName,
  53                                 attrInfo.type, offset, buffer, bytesRead);
  54                         if (bytesWritten < 0)
  55                                 return bytesWritten;
  56
  57                         bytesLeft -= bytesRead;
  58                         offset += bytesRead;
  59                 } while (bytesLeft > 0);
  60         }
  61         return B_OK;
  62 }
  63
  64
  65 }       // namespace BPrivate
  66