1 //===--- A platform independent Dir class ---------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef LLVM_LIBC_SRC___SUPPORT_FILE_DIR_H 10 #define LLVM_LIBC_SRC___SUPPORT_FILE_DIR_H 11 12 #include "src/__support/CPP/span.h" 13 #include "src/__support/error_or.h" 14 #include "src/__support/macros/config.h" 15 #include "src/__support/threads/mutex.h" 16 17 #include <dirent.h> 18 19 namespace LIBC_NAMESPACE_DECL { 20 21 // Platform specific function which will open the directory |name| 22 // and return its file descriptor. Upon failure, the error value is returned. 23 ErrorOr<int> platform_opendir(const char *name); 24 25 // Platform specific function which will close the directory with 26 // file descriptor |fd|. Returns 0 on success, or the error number on failure. 27 int platform_closedir(int fd); 28 29 // Platform specific function which will fetch dirents in to buffer. 30 // Returns the number of bytes written into buffer or the error number on 31 // failure. 32 ErrorOr<size_t> platform_fetch_dirents(int fd, cpp::span<uint8_t> buffer); 33 34 // This class is designed to allow implementation of the POSIX dirent.h API. 35 // By itself, it is platform independent but calls platform specific 36 // functions to perform OS operations. 37 class Dir { 38 static constexpr size_t BUFSIZE = 1024; 39 int fd; 40 size_t readptr = 0; // The current read pointer. 41 size_t fillsize = 0; // The number of valid bytes availabe in the buffer. 42 43 // This is a buffer of struct dirent values which will be fetched 44 // from the OS. Since the d_name of struct dirent can be of a variable 45 // size, we store the data in a byte array. 46 uint8_t buffer[BUFSIZE]; 47 48 Mutex mutex; 49 50 // A directory is to be opened by the static method open and closed 51 // by the close method. So, all constructors and destructor are declared 52 // as private. Inappropriate constructors are declared as deleted. 53 LIBC_INLINE Dir() = delete; 54 LIBC_INLINE Dir(const Dir &) = delete; 55 Dir(int fdesc)56 LIBC_INLINE explicit Dir(int fdesc) 57 : fd(fdesc), readptr(0), fillsize(0), 58 mutex(/*timed=*/false, /*recursive=*/false, /*robust=*/false, 59 /*pshared=*/false) {} 60 LIBC_INLINE ~Dir() = default; 61 62 LIBC_INLINE Dir &operator=(const Dir &) = delete; 63 64 public: 65 static ErrorOr<Dir *> open(const char *path); 66 67 ErrorOr<struct ::dirent *> read(); 68 69 // Returns 0 on success or the error number on failure. If an error number 70 // was returned, then the resources associated with the directory are not 71 // cleaned up. 72 int close(); 73 getfd()74 LIBC_INLINE int getfd() { return fd; } 75 }; 76 77 } // namespace LIBC_NAMESPACE_DECL 78 79 #endif // LLVM_LIBC_SRC___SUPPORT_FILE_DIR_H 80