ipc/chromium/src/base/dir_reader_linux.h

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