1//===-- runtime/file.h ------------------------------------------*- C++ -*-===//
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// Raw system I/O wrappers
10
11#ifndef FORTRAN_RUNTIME_FILE_H_
12#define FORTRAN_RUNTIME_FILE_H_
13
14#include "io-error.h"
15#include "flang/Runtime/memory.h"
16#include <cinttypes>
17#include <optional>
18
19namespace Fortran::runtime::io {
20
21enum class OpenStatus { Old, New, Scratch, Replace, Unknown };
22enum class CloseStatus { Keep, Delete };
23enum class Position { AsIs, Rewind, Append };
24enum class Action { Read, Write, ReadWrite };
25
26class OpenFile {
27public:
28 using FileOffset = std::int64_t;
29
30 const char *path() const { return path_.get(); }
31 std::size_t pathLength() const { return pathLength_; }
32 void set_path(OwningPtr<char> &&, std::size_t bytes);
33 bool mayRead() const { return mayRead_; }
34 bool mayWrite() const { return mayWrite_; }
35 bool mayPosition() const { return mayPosition_; }
36 bool mayAsynchronous() const { return mayAsynchronous_; }
37 void set_mayAsynchronous(bool yes) { mayAsynchronous_ = yes; }
38 bool isTerminal() const { return isTerminal_; }
39 bool isWindowsTextFile() const { return isWindowsTextFile_; }
40 std::optional<FileOffset> knownSize() const { return knownSize_; }
41
42 bool IsConnected() const { return fd_ >= 0; }
43 void Open(OpenStatus, std::optional<Action>, Position, IoErrorHandler &);
44 void Predefine(int fd);
45 void Close(CloseStatus, IoErrorHandler &);
46
47 // Reads data into memory; returns amount acquired. Synchronous.
48 // Partial reads (less than minBytes) signify end-of-file. If the
49 // buffer is larger than minBytes, and extra returned data will be
50 // preserved for future consumption, set maxBytes larger than minBytes
51 // to reduce system calls This routine handles EAGAIN/EWOULDBLOCK and EINTR.
52 std::size_t Read(FileOffset, char *, std::size_t minBytes,
53 std::size_t maxBytes, IoErrorHandler &);
54
55 // Writes data. Synchronous. Partial writes indicate program-handled
56 // error conditions.
57 std::size_t Write(FileOffset, const char *, std::size_t, IoErrorHandler &);
58
59 // Truncates the file
60 void Truncate(FileOffset, IoErrorHandler &);
61
62 // Asynchronous transfers
63 int ReadAsynchronously(FileOffset, char *, std::size_t, IoErrorHandler &);
64 int WriteAsynchronously(
65 FileOffset, const char *, std::size_t, IoErrorHandler &);
66 void Wait(int id, IoErrorHandler &);
67 void WaitAll(IoErrorHandler &);
68
69 // INQUIRE(POSITION=)
70 Position InquirePosition() const;
71
72private:
73 struct Pending {
74 int id;
75 int ioStat{0};
76 OwningPtr<Pending> next;
77 };
78
79 void CheckOpen(const Terminator &);
80 bool Seek(FileOffset, IoErrorHandler &);
81 bool RawSeek(FileOffset);
82 bool RawSeekToEnd();
83 int PendingResult(const Terminator &, int);
84 void SetPosition(FileOffset pos) {
85 position_ = pos;
86 openPosition_.reset();
87 }
88 void CloseFd(IoErrorHandler &);
89
90 int fd_{-1};
91 OwningPtr<char> path_;
92 std::size_t pathLength_;
93 bool mayRead_{false};
94 bool mayWrite_{false};
95 bool mayPosition_{false};
96 bool mayAsynchronous_{false};
97 std::optional<Position> openPosition_; // from Open(); reset after positioning
98 FileOffset position_{0};
99 std::optional<FileOffset> knownSize_;
100 bool isTerminal_{false};
101 bool isWindowsTextFile_{false}; // expands LF to CR+LF on write
102
103 int nextId_;
104 OwningPtr<Pending> pending_;
105};
106
107bool IsATerminal(int fd);
108bool IsExtant(const char *path);
109bool MayRead(const char *path);
110bool MayWrite(const char *path);
111bool MayReadAndWrite(const char *path);
112std::int64_t SizeInBytes(const char *path);
113} // namespace Fortran::runtime::io
114#endif // FORTRAN_RUNTIME_FILE_H_
115

source code of flang/runtime/file.h