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//===-- runtime/unit.h ------------------------------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
// Fortran external I/O units
#ifndef FORTRAN_RUNTIME_IO_UNIT_H_
#define FORTRAN_RUNTIME_IO_UNIT_H_
#include "buffer.h"
#include "connection.h"
#include "environment.h"
#include "file.h"
#include "format.h"
#include "io-error.h"
#include "io-stmt.h"
#include "lock.h"
#include "terminator.h"
#include "flang/Common/constexpr-bitset.h"
#include "flang/Runtime/memory.h"
#include <cstdlib>
#include <cstring>
#include <optional>
#include <variant>
namespace Fortran::runtime::io {
class UnitMap;
class ChildIo;
class ExternalFileUnit : public ConnectionState,
public OpenFile,
public FileFrame<ExternalFileUnit> {
public:
explicit ExternalFileUnit(int unitNumber) : unitNumber_{unitNumber} {
isUTF8 = executionEnvironment.defaultUTF8;
asyncIdAvailable_.set();
asyncIdAvailable_.reset(0);
}
~ExternalFileUnit() {}
int unitNumber() const { return unitNumber_; }
bool swapEndianness() const { return swapEndianness_; }
bool createdForInternalChildIo() const { return createdForInternalChildIo_; }
static ExternalFileUnit *LookUp(int unit);
static ExternalFileUnit *LookUpOrCreate(
int unit, const Terminator &, bool &wasExtant);
static ExternalFileUnit *LookUpOrCreateAnonymous(int unit, Direction,
std::optional<bool> isUnformatted, const Terminator &);
static ExternalFileUnit *LookUp(const char *path, std::size_t pathLen);
static ExternalFileUnit &CreateNew(int unit, const Terminator &);
static ExternalFileUnit *LookUpForClose(int unit);
static ExternalFileUnit &NewUnit(const Terminator &, bool forChildIo);
static void CloseAll(IoErrorHandler &);
static void FlushAll(IoErrorHandler &);
void OpenUnit(std::optional<OpenStatus>, std::optional<Action>, Position,
OwningPtr<char> &&path, std::size_t pathLength, Convert,
IoErrorHandler &);
void OpenAnonymousUnit(std::optional<OpenStatus>, std::optional<Action>,
Position, Convert, IoErrorHandler &);
void CloseUnit(CloseStatus, IoErrorHandler &);
void DestroyClosed();
Iostat SetDirection(Direction);
template <typename A, typename... X>
IoStatementState &BeginIoStatement(const Terminator &terminator, X &&...xs) {
bool alreadyBusy{false};
{
CriticalSection critical{lock_};
alreadyBusy = isBusy_;
isBusy_ = true; // cleared in EndIoStatement()
}
if (alreadyBusy) {
terminator.Crash("Could not acquire exclusive lock on unit %d, perhaps "
"due to an attempt to perform recursive I/O",
unitNumber_);
}
A &state{u_.emplace<A>(std::forward<X>(xs)...)};
if constexpr (!std::is_same_v<A, OpenStatementState>) {
state.mutableModes() = ConnectionState::modes;
}
directAccessRecWasSet_ = false;
io_.emplace(state);
return *io_;
}
bool Emit(
const char *, std::size_t, std::size_t elementBytes, IoErrorHandler &);
bool Receive(char *, std::size_t, std::size_t elementBytes, IoErrorHandler &);
std::size_t GetNextInputBytes(const char *&, IoErrorHandler &);
bool BeginReadingRecord(IoErrorHandler &);
void FinishReadingRecord(IoErrorHandler &);
bool AdvanceRecord(IoErrorHandler &);
void BackspaceRecord(IoErrorHandler &);
void FlushOutput(IoErrorHandler &);
void FlushIfTerminal(IoErrorHandler &);
void Endfile(IoErrorHandler &);
void Rewind(IoErrorHandler &);
void EndIoStatement();
bool SetStreamPos(std::int64_t, IoErrorHandler &); // one-based, for POS=
bool SetDirectRec(std::int64_t, IoErrorHandler &); // one-based, for REC=
std::int64_t InquirePos() const {
// 12.6.2.11 defines POS=1 as the beginning of file
return frameOffsetInFile_ + recordOffsetInFrame_ + positionInRecord + 1;
}
ChildIo *GetChildIo() { return child_.get(); }
ChildIo &PushChildIo(IoStatementState &);
void PopChildIo(ChildIo &);
int GetAsynchronousId(IoErrorHandler &);
bool Wait(int);
private:
static UnitMap &GetUnitMap();
const char *FrameNextInput(IoErrorHandler &, std::size_t);
void SetPosition(std::int64_t, IoErrorHandler &); // zero-based
void BeginSequentialVariableUnformattedInputRecord(IoErrorHandler &);
void BeginVariableFormattedInputRecord(IoErrorHandler &);
void BackspaceFixedRecord(IoErrorHandler &);
void BackspaceVariableUnformattedRecord(IoErrorHandler &);
void BackspaceVariableFormattedRecord(IoErrorHandler &);
bool SetVariableFormattedRecordLength();
void DoImpliedEndfile(IoErrorHandler &);
void DoEndfile(IoErrorHandler &);
void CommitWrites();
bool CheckDirectAccess(IoErrorHandler &);
void HitEndOnRead(IoErrorHandler &);
Lock lock_;
// TODO: replace with a thread ID
bool isBusy_{false}; // under lock_
int unitNumber_{-1};
Direction direction_{Direction::Output};
bool impliedEndfile_{false}; // sequential/stream output has taken place
bool beganReadingRecord_{false};
bool directAccessRecWasSet_{false}; // REC= appeared
// Subtle: The beginning of the frame can't be allowed to advance
// during a single list-directed READ due to the possibility of a
// multi-record CHARACTER value with a "r*" repeat count. So we
// manage the frame and the current record therein separately.
std::int64_t frameOffsetInFile_{0};
std::size_t recordOffsetInFrame_{0}; // of currentRecordNumber
bool swapEndianness_{false};
bool createdForInternalChildIo_{false};
common::BitSet<64> asyncIdAvailable_;
// When a synchronous I/O statement is in progress on this unit, holds its
// state.
std::variant<std::monostate, OpenStatementState, CloseStatementState,
ExternalFormattedIoStatementState<Direction::Output>,
ExternalFormattedIoStatementState<Direction::Input>,
ExternalListIoStatementState<Direction::Output>,
ExternalListIoStatementState<Direction::Input>,
ExternalUnformattedIoStatementState<Direction::Output>,
ExternalUnformattedIoStatementState<Direction::Input>, InquireUnitState,
ExternalMiscIoStatementState, ErroneousIoStatementState>
u_;
// Points to the active alternative (if any) in u_ for use as a Cookie
std::optional<IoStatementState> io_;
// A stack of child I/O pseudo-units for user-defined derived type
// I/O that have this unit number.
OwningPtr<ChildIo> child_;
};
// A pseudo-unit for child I/O statements in user-defined derived type
// I/O subroutines; it forwards operations to the parent I/O statement,
// which can also be a child I/O statement.
class ChildIo {
public:
ChildIo(IoStatementState &parent, OwningPtr<ChildIo> &&previous)
: parent_{parent}, previous_{std::move(previous)} {}
IoStatementState &parent() const { return parent_; }
void EndIoStatement();
template <typename A, typename... X>
IoStatementState &BeginIoStatement(X &&...xs) {
A &state{u_.emplace<A>(std::forward<X>(xs)...)};
io_.emplace(state);
return *io_;
}
OwningPtr<ChildIo> AcquirePrevious() { return std::move(previous_); }
Iostat CheckFormattingAndDirection(bool unformatted, Direction);
private:
IoStatementState &parent_;
OwningPtr<ChildIo> previous_;
std::variant<std::monostate,
ChildFormattedIoStatementState<Direction::Output>,
ChildFormattedIoStatementState<Direction::Input>,
ChildListIoStatementState<Direction::Output>,
ChildListIoStatementState<Direction::Input>,
ChildUnformattedIoStatementState<Direction::Output>,
ChildUnformattedIoStatementState<Direction::Input>, InquireUnitState,
ErroneousIoStatementState>
u_;
std::optional<IoStatementState> io_;
};
} // namespace Fortran::runtime::io
#endif // FORTRAN_RUNTIME_IO_UNIT_H_