//===- PathV3.inc ---------------------------------------------------------===//
//
//                     The MCLinker Project
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include <mcld/Support/Path.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stack>

namespace mcld{
namespace sys{
namespace fs{

//===----------------------------------------------------------------------===//
// mcld::sys::fs::detail
//===----------------------------------------------------------------------===//
namespace detail{

// return the last charactor being handled.
size_t canonicalize(std::string& pathname)
{
  // Variable Index //
  // SepTable - stack of result separators
  // LR(1) Algorithm //
  // traverse pPathName
  //   if we meet '//', '///', '////', ...
  //     -> ignore it
  //     -> push current into stack
  //     -> jump to the next not '/'
  //   if we meet '/./'
  //     -> ignore
  //     -> jump to the next not '/'
  //   if we meet '/../'
  //     -> pop previous position of '/' P
  //     -> erase P+1 to now
  //   if we meet other else
  //     -> go go go
  //   if we meet '/.../', '/..../', ... -> illegal
  if (pathname.empty())
    return 0;

  size_t handler = 0;
  std::stack<size_t> slash_stack;
  slash_stack.push(-1);
  while (handler < pathname.size()) {
    if (separator == pathname[handler]) { // handler = 1st '/'
      size_t next = handler + 1;
      if (next >= pathname.size())
        return handler;
      switch(pathname[next]) { // next = handler + 1;
        case separator: { // '//'
          while (next < pathname.size() && separator == pathname[next])
            ++next;
          // next is the last not '/'
          pathname.erase(handler, next - handler - 1);
          // handler is the first '/'
          slash_stack.push(handler);
          break;
        }
        case '.': { // '/.'
          ++next; // next = handler + 2
          if (next >= pathname.size()) // '/.'
            return handler;
          switch (pathname[next]) {
            case separator: { // '/./'
              pathname.erase(handler, 2);
              break;
            }
            case '.': { // '/..'
              ++next; // next = handler + 3;
              if (next >= pathname.size()) // '/..?'
                return handler;
              switch(pathname[next]) {
                case separator: { // '/../'
                  handler = slash_stack.top();
                  slash_stack.pop();
                  pathname.erase(handler+1, next-handler);
                  if (static_cast<size_t>(-1) == handler) {
                    slash_stack.push(-1);
                    handler = pathname.find_first_of(separator, handler);
                  }
                  break;
                }
                case '.': { // '/...', illegal
                  return handler;
                  break;
                }
                default : { // '/..a'
                  slash_stack.push(handler);
                  handler = pathname.find_first_of(separator, handler+3);
                  break;
                }
              }
              break;
            }
            default : { // '/.a'
              slash_stack.push(handler);
              handler = pathname.find_first_of(separator, handler+2);
              break;
            }
          }
          break;
        }
        default : { // '/a
          slash_stack.push(handler);
          handler = pathname.find_first_of(separator, handler+1);
          break;
        }
      }
    }
    else {
      handler = pathname.find_first_of(separator, handler);
    }
  }
  return handler;
}

bool not_found_error(int perrno)
{
  return perrno == ENOENT || perrno == ENOTDIR;
}

void status(const Path& p, FileStatus& pFileStatus)
{
  struct ::_stat path_stat;
  if(::_stat(p.c_str(), &path_stat)!= 0)
  {
    if(not_found_error(errno))
    {
      pFileStatus.setType(FileNotFound);
    }
    else
      pFileStatus.setType(StatusError);
  }
  else if(S_ISDIR(path_stat.st_mode))
    pFileStatus.setType(DirectoryFile);
  else if(S_ISREG(path_stat.st_mode))
    pFileStatus.setType(RegularFile);
  else if(S_ISBLK(path_stat.st_mode))
    pFileStatus.setType(BlockFile);
  else if(S_ISCHR(path_stat.st_mode))
    pFileStatus.setType(CharacterFile);
  else if(S_ISFIFO(path_stat.st_mode))
    pFileStatus.setType(FifoFile);
  else
    pFileStatus.setType(TypeUnknown);
}

void symlink_status(const Path& p, FileStatus& pFileStatus)
{
  pFileStatus.setType(FileNotFound);
}

/// directory_iterator_increment - increment function implementation
//
//  iterator will call this function in two situations:
//  1. All elements have been put into cache, and iterator stays at the end
//     of cache. (a real end)
//  2. Some but not all elements had beed put into cache, and we stoped.
//     An iterator now is staying at the end of cache. (a temporal end)
mcld::sys::fs::PathCache::entry_type* bring_one_into_cache(DirIterator& pIter)
{
  mcld::sys::fs::PathCache::entry_type* entry = 0;
  fs::Path file_filter(pIter.m_pParent->m_Path);
  file_filter.append("*");

  WIN32_FIND_DATA FindFileData;
  if (FindNextFile(reinterpret_cast<HANDLE>(pIter.m_pParent->m_Handler),
                   &FindFileData)) {
    // read one
    bool exist = false;
    std::string path(pIter.m_pParent->m_Path.native());
    path += separator;
    path += std::string(FindFileData.cFileName);
    entry = pIter.m_pParent->m_Cache.insert(path, exist);
    if (!exist)
      entry->setValue(path);
  }
  else if (ERROR_NO_MORE_FILES == GetLastError()){
    // meet real end
    pIter.m_pParent->m_CacheFull = true;
  }
  else {
    llvm::report_fatal_error(std::string("Can't read directory: ")+
                             pIter.m_pParent->path().native());
  }

  return entry;
}

} // namespace of detail
} // namespace of fs
} // namespace of sys
} // namespace of mcld