dir_reader_linux.h revision c407dc5cd9bdc5668497f21b26b09d988ab439de 
1// Copyright (c) 2010 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef BASE_DIR_READER_LINUX_H_
6#define BASE_DIR_READER_LINUX_H_
7
8#include <errno.h>
9#include <fcntl.h>
10#include <stdint.h>
11#include <sys/syscall.h>
12#include <unistd.h>
13
14#include "base/logging.h"
15#include "base/eintr_wrapper.h"
16
17// See the comments in dir_reader_posix.h about this.
18
19namespace base {
20
21struct linux_dirent {
22  uint64_t        d_ino;
23  int64_t         d_off;
24  unsigned short  d_reclen;
25  unsigned char   d_type;
26  char            d_name[0];
27};
28
29class DirReaderLinux {
30 public:
31  explicit DirReaderLinux(const char* directory_path)
32      : fd_(open(directory_path, O_RDONLY | O_DIRECTORY)),
33        offset_(0),
34        size_(0) {
35  }
36
37  ~DirReaderLinux() {
38    if (fd_ >= 0) {
39      if (HANDLE_EINTR(close(fd_)))
40        RAW_LOG(ERROR, "Failed to close directory handle");
41    }
42  }
43
44  bool IsValid() const {
45    return fd_ >= 0;
46  }
47
48  // Move to the next entry returning false if the iteration is complete.
49  bool Next() {
50    if (size_) {
51      linux_dirent* dirent = reinterpret_cast<linux_dirent*>(&buf_[offset_]);
52      offset_ += dirent->d_reclen;
53    }
54
55    if (offset_ != size_)
56      return true;
57
58    const int r = syscall(__NR_getdents64, fd_, buf_, sizeof(buf_));
59    if (r == 0)
60      return false;
61    if (r == -1) {
62      DPLOG(FATAL) << "getdents64 returned an error: " << errno;
63      return false;
64    }
65    size_ = r;
66    offset_ = 0;
67    return true;
68  }
69
70  const char* name() const {
71    if (!size_)
72      return NULL;
73
74    const linux_dirent* dirent =
75        reinterpret_cast<const linux_dirent*>(&buf_[offset_]);
76    return dirent->d_name;
77  }
78
79  int fd() const {
80    return fd_;
81  }
82
83  static bool IsFallback() {
84    return false;
85  }
86
87 private:
88  const int fd_;
89  unsigned char buf_[512];
90  size_t offset_, size_;
91
92  DISALLOW_COPY_AND_ASSIGN(DirReaderLinux);
93};
94
95}  // namespace base
96
97#endif // BASE_DIR_READER_LINUX_H_
98