1//===-- runtime/unit.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// Fortran external I/O units
10
11#ifndef FORTRAN_RUNTIME_IO_UNIT_H_
12#define FORTRAN_RUNTIME_IO_UNIT_H_
13
14#include "buffer.h"
15#include "connection.h"
16#include "environment.h"
17#include "file.h"
18#include "format.h"
19#include "io-error.h"
20#include "io-stmt.h"
21#include "lock.h"
22#include "terminator.h"
23#include "flang/Common/constexpr-bitset.h"
24#include "flang/Runtime/memory.h"
25#include <cstdlib>
26#include <cstring>
27#include <optional>
28#include <variant>
29
30namespace Fortran::runtime::io {
31
32class UnitMap;
33class ChildIo;
34
35class ExternalFileUnit : public ConnectionState,
36 public OpenFile,
37 public FileFrame<ExternalFileUnit> {
38public:
39 explicit ExternalFileUnit(int unitNumber) : unitNumber_{unitNumber} {
40 isUTF8 = executionEnvironment.defaultUTF8;
41 asyncIdAvailable_.set();
42 asyncIdAvailable_.reset(0);
43 }
44 ~ExternalFileUnit() {}
45
46 int unitNumber() const { return unitNumber_; }
47 bool swapEndianness() const { return swapEndianness_; }
48 bool createdForInternalChildIo() const { return createdForInternalChildIo_; }
49
50 static ExternalFileUnit *LookUp(int unit);
51 static ExternalFileUnit *LookUpOrCreate(
52 int unit, const Terminator &, bool &wasExtant);
53 static ExternalFileUnit *LookUpOrCreateAnonymous(int unit, Direction,
54 std::optional<bool> isUnformatted, const Terminator &);
55 static ExternalFileUnit *LookUp(const char *path, std::size_t pathLen);
56 static ExternalFileUnit &CreateNew(int unit, const Terminator &);
57 static ExternalFileUnit *LookUpForClose(int unit);
58 static ExternalFileUnit &NewUnit(const Terminator &, bool forChildIo);
59 static void CloseAll(IoErrorHandler &);
60 static void FlushAll(IoErrorHandler &);
61
62 // Returns true if an existing unit was closed
63 bool OpenUnit(std::optional<OpenStatus>, std::optional<Action>, Position,
64 OwningPtr<char> &&path, std::size_t pathLength, Convert,
65 IoErrorHandler &);
66 void OpenAnonymousUnit(std::optional<OpenStatus>, std::optional<Action>,
67 Position, Convert, IoErrorHandler &);
68 void CloseUnit(CloseStatus, IoErrorHandler &);
69 void DestroyClosed();
70
71 Iostat SetDirection(Direction);
72
73 template <typename A, typename... X>
74 IoStatementState &BeginIoStatement(const Terminator &terminator, X &&...xs) {
75 // Take lock_ and hold it until EndIoStatement().
76#if USE_PTHREADS
77 if (!lock_.TakeIfNoDeadlock()) {
78 terminator.Crash("Recursive I/O attempted on unit %d", unitNumber_);
79 }
80#else
81 lock_.Take();
82#endif
83 A &state{u_.emplace<A>(std::forward<X>(xs)...)};
84 if constexpr (!std::is_same_v<A, OpenStatementState>) {
85 state.mutableModes() = ConnectionState::modes;
86 }
87 directAccessRecWasSet_ = false;
88 io_.emplace(state);
89 return *io_;
90 }
91
92 bool Emit(
93 const char *, std::size_t, std::size_t elementBytes, IoErrorHandler &);
94 bool Receive(char *, std::size_t, std::size_t elementBytes, IoErrorHandler &);
95 std::size_t GetNextInputBytes(const char *&, IoErrorHandler &);
96 bool BeginReadingRecord(IoErrorHandler &);
97 void FinishReadingRecord(IoErrorHandler &);
98 bool AdvanceRecord(IoErrorHandler &);
99 void BackspaceRecord(IoErrorHandler &);
100 void FlushOutput(IoErrorHandler &);
101 void FlushIfTerminal(IoErrorHandler &);
102 void Endfile(IoErrorHandler &);
103 void Rewind(IoErrorHandler &);
104 void EndIoStatement();
105 bool SetStreamPos(std::int64_t, IoErrorHandler &); // one-based, for POS=
106 bool SetDirectRec(std::int64_t, IoErrorHandler &); // one-based, for REC=
107 std::int64_t InquirePos() const {
108 // 12.6.2.11 defines POS=1 as the beginning of file
109 return frameOffsetInFile_ + recordOffsetInFrame_ + positionInRecord + 1;
110 }
111
112 ChildIo *GetChildIo() { return child_.get(); }
113 ChildIo &PushChildIo(IoStatementState &);
114 void PopChildIo(ChildIo &);
115
116 int GetAsynchronousId(IoErrorHandler &);
117 bool Wait(int);
118
119private:
120 static UnitMap &CreateUnitMap();
121 static UnitMap &GetUnitMap();
122 const char *FrameNextInput(IoErrorHandler &, std::size_t);
123 void SetPosition(std::int64_t, IoErrorHandler &); // zero-based
124 void BeginSequentialVariableUnformattedInputRecord(IoErrorHandler &);
125 void BeginVariableFormattedInputRecord(IoErrorHandler &);
126 void BackspaceFixedRecord(IoErrorHandler &);
127 void BackspaceVariableUnformattedRecord(IoErrorHandler &);
128 void BackspaceVariableFormattedRecord(IoErrorHandler &);
129 bool SetVariableFormattedRecordLength();
130 void DoImpliedEndfile(IoErrorHandler &);
131 void DoEndfile(IoErrorHandler &);
132 void CommitWrites();
133 bool CheckDirectAccess(IoErrorHandler &);
134 void HitEndOnRead(IoErrorHandler &);
135 std::int32_t ReadHeaderOrFooter(std::int64_t frameOffset);
136
137 Lock lock_;
138
139 int unitNumber_{-1};
140 Direction direction_{Direction::Output};
141 bool impliedEndfile_{false}; // sequential/stream output has taken place
142 bool beganReadingRecord_{false};
143 bool anyWriteSinceLastPositioning_{false};
144 bool directAccessRecWasSet_{false}; // REC= appeared
145 // Subtle: The beginning of the frame can't be allowed to advance
146 // during a single list-directed READ due to the possibility of a
147 // multi-record CHARACTER value with a "r*" repeat count. So we
148 // manage the frame and the current record therein separately.
149 std::int64_t frameOffsetInFile_{0};
150 std::size_t recordOffsetInFrame_{0}; // of currentRecordNumber
151 bool swapEndianness_{false};
152 bool createdForInternalChildIo_{false};
153 common::BitSet<64> asyncIdAvailable_;
154
155 // When a synchronous I/O statement is in progress on this unit, holds its
156 // state.
157 std::variant<std::monostate, OpenStatementState, CloseStatementState,
158 ExternalFormattedIoStatementState<Direction::Output>,
159 ExternalFormattedIoStatementState<Direction::Input>,
160 ExternalListIoStatementState<Direction::Output>,
161 ExternalListIoStatementState<Direction::Input>,
162 ExternalUnformattedIoStatementState<Direction::Output>,
163 ExternalUnformattedIoStatementState<Direction::Input>, InquireUnitState,
164 ExternalMiscIoStatementState, ErroneousIoStatementState>
165 u_;
166
167 // Points to the active alternative (if any) in u_ for use as a Cookie
168 std::optional<IoStatementState> io_;
169
170 // A stack of child I/O pseudo-units for defined I/O that have this
171 // unit number.
172 OwningPtr<ChildIo> child_;
173};
174
175// A pseudo-unit for child I/O statements in defined I/O subroutines;
176// it forwards operations to the parent I/O statement, which might also
177// be a child I/O statement.
178class ChildIo {
179public:
180 ChildIo(IoStatementState &parent, OwningPtr<ChildIo> &&previous)
181 : parent_{parent}, previous_{std::move(previous)} {}
182
183 IoStatementState &parent() const { return parent_; }
184
185 void EndIoStatement();
186
187 template <typename A, typename... X>
188 IoStatementState &BeginIoStatement(X &&...xs) {
189 A &state{u_.emplace<A>(std::forward<X>(xs)...)};
190 io_.emplace(state);
191 return *io_;
192 }
193
194 OwningPtr<ChildIo> AcquirePrevious() { return std::move(previous_); }
195
196 Iostat CheckFormattingAndDirection(bool unformatted, Direction);
197
198private:
199 IoStatementState &parent_;
200 OwningPtr<ChildIo> previous_;
201 std::variant<std::monostate,
202 ChildFormattedIoStatementState<Direction::Output>,
203 ChildFormattedIoStatementState<Direction::Input>,
204 ChildListIoStatementState<Direction::Output>,
205 ChildListIoStatementState<Direction::Input>,
206 ChildUnformattedIoStatementState<Direction::Output>,
207 ChildUnformattedIoStatementState<Direction::Input>, InquireUnitState,
208 ErroneousIoStatementState, ExternalMiscIoStatementState>
209 u_;
210 std::optional<IoStatementState> io_;
211};
212
213} // namespace Fortran::runtime::io
214#endif // FORTRAN_RUNTIME_IO_UNIT_H_
215

source code of flang/runtime/unit.h