Move dir_reader to base/files

base/dir_reader_linux.h

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef BASE_DIR_READER_LINUX_H_
-#define BASE_DIR_READER_LINUX_H_
-#pragma once
-
-#include <errno.h>
-#include <fcntl.h>
-#include <stdint.h>
-#include <sys/syscall.h>
-#include <unistd.h>
-
-#include "base/logging.h"
-#include "base/eintr_wrapper.h"
-
-// See the comments in dir_reader_posix.h about this.
-
-namespace base {
-
-struct linux_dirent {
-  uint64_t        d_ino;
-  int64_t         d_off;
-  unsigned short  d_reclen;
-  unsigned char   d_type;
-  char            d_name[0];
-};
-
-class DirReaderLinux {
- public:
-  explicit DirReaderLinux(const char* directory_path)
-      : fd_(open(directory_path, O_RDONLY | O_DIRECTORY)),
-        offset_(0),
-        size_(0) {
-    memset(buf_, 0, sizeof(buf_));
-  }
-
-  ~DirReaderLinux() {
-    if (fd_ >= 0) {
-      if (HANDLE_EINTR(close(fd_)))
-        RAW_LOG(ERROR, "Failed to close directory handle");
-    }
-  }
-
-  bool IsValid() const {
-    return fd_ >= 0;
-  }
-
-  // Move to the next entry returning false if the iteration is complete.
-  bool Next() {
-    if (size_) {
-      linux_dirent* dirent = reinterpret_cast<linux_dirent*>(&buf_[offset_]);
-      offset_ += dirent->d_reclen;
-    }
-
-    if (offset_ != size_)
-      return true;
-
-    const int r = syscall(__NR_getdents64, fd_, buf_, sizeof(buf_));
-    if (r == 0)
-      return false;
-    if (r == -1) {
-      DPLOG(FATAL) << "getdents64 returned an error: " << errno;
-      return false;
-    }
-    size_ = r;
-    offset_ = 0;
-    return true;
-  }
-
-  const char* name() const {
-    if (!size_)
-      return NULL;
-
-    const linux_dirent* dirent =
-        reinterpret_cast<const linux_dirent*>(&buf_[offset_]);
-    return dirent->d_name;
-  }
-
-  int fd() const {
-    return fd_;
-  }
-
-  static bool IsFallback() {
-    return false;
-  }
-
- private:
-  const int fd_;
-  unsigned char buf_[512];
-  size_t offset_, size_;
-
-  DISALLOW_COPY_AND_ASSIGN(DirReaderLinux);
-};
-
-}  // namespace base
-
-#endif // BASE_DIR_READER_LINUX_H_