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//===--- A platform independent Dir class ---------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_SRC___SUPPORT_FILE_DIR_H
#define LLVM_LIBC_SRC___SUPPORT_FILE_DIR_H
#include "src/__support/CPP/span.h"
#include "src/__support/error_or.h"
#include "src/__support/threads/mutex.h"
#include <dirent.h>
#include <stdlib.h>
namespace __llvm_libc {
// Platform specific function which will open the directory |name|
// and return its file descriptor. Upon failure, the error value is returned.
ErrorOr<int> platform_opendir(const char *name);
// Platform specific function which will close the directory with
// file descriptor |fd|. Returns 0 on success, or the error number on failure.
int platform_closedir(int fd);
// Platform specific function which will fetch dirents in to buffer.
// Returns the number of bytes written into buffer or the error number on
// failure.
ErrorOr<size_t> platform_fetch_dirents(int fd, cpp::span<uint8_t> buffer);
// This class is designed to allow implementation of the POSIX dirent.h API.
// By itself, it is platform independent but calls platform specific
// functions to perform OS operations.
class Dir {
static constexpr size_t BUFSIZE = 1024;
int fd;
size_t readptr = 0; // The current read pointer.
size_t fillsize = 0; // The number of valid bytes availabe in the buffer.
// This is a buffer of struct dirent values which will be fetched
// from the OS. Since the d_name of struct dirent can be of a variable
// size, we store the data in a byte array.
uint8_t buffer[BUFSIZE];
Mutex mutex;
// A directory is to be opened by the static method open and closed
// by the close method. So, all constructors and destructor are declared
// as private. Inappropriate constructors are declared as deleted.
Dir() = delete;
Dir(const Dir &) = delete;
explicit Dir(int fdesc)
: fd(fdesc), readptr(0), fillsize(0), mutex(false, false, false) {}
~Dir() = default;
Dir &operator=(const Dir &) = delete;
public:
static ErrorOr<Dir *> open(const char *path);
ErrorOr<struct ::dirent *> read();
// Returns 0 on success or the error number on failure. If an error number
// was returned, then the resources associated with the directory are not
// cleaned up.
int close();
int getfd() { return fd; }
};
} // namespace __llvm_libc
#endif // LLVM_LIBC_SRC___SUPPORT_FILE_DIR_H
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