flang/runtime/unit.h

   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/Common/optional.h"
  25 #include "flang/Runtime/memory.h"
  26 #include <cstdlib>
  27 #include <cstring>
  28 #include <flang/Common/variant.h>
  29
  30 namespace Fortran::runtime::io {
  31
  32 class UnitMap;
  33 class ChildIo;
  34 class ExternalFileUnit;
  35
  36 RT_OFFLOAD_VAR_GROUP_BEGIN
  37 // Predefined file units.
  38 extern RT_VAR_ATTRS ExternalFileUnit *defaultInput; // unit 5
  39 extern RT_VAR_ATTRS ExternalFileUnit *defaultOutput; // unit 6
  40 extern RT_VAR_ATTRS ExternalFileUnit *errorOutput; // unit 0 extension
  41 RT_OFFLOAD_VAR_GROUP_END
  42
  43 #if defined(RT_USE_PSEUDO_FILE_UNIT)
  44 // A flavor of OpenFile class that pretends to be a terminal,
  45 // and only provides basic buffering of the output
  46 // in an internal buffer, and Write's the output
  47 // using std::printf(). Since it does not rely on file system
  48 // APIs, it can be used to implement external output
  49 // for offload devices.
  50 class PseudoOpenFile {
  51 public:
  52   using FileOffset = std::int64_t;
  53
  54   RT_API_ATTRS const char *path() const { return nullptr; }
  55   RT_API_ATTRS std::size_t pathLength() const { return 0; }
  56   RT_API_ATTRS void set_path(OwningPtr<char> &&, std::size_t bytes) {}
  57   RT_API_ATTRS bool mayRead() const { return false; }
  58   RT_API_ATTRS bool mayWrite() const { return true; }
  59   RT_API_ATTRS bool mayPosition() const { return false; }
  60   RT_API_ATTRS bool mayAsynchronous() const { return false; }
  61   RT_API_ATTRS void set_mayAsynchronous(bool yes);
  62   // Pretend to be a terminal to force the output
  63   // at the end of IO statement.
  64   RT_API_ATTRS bool isTerminal() const { return true; }
  65   RT_API_ATTRS bool isWindowsTextFile() const { return false; }
  66   RT_API_ATTRS Fortran::common::optional<FileOffset> knownSize() const;
  67   RT_API_ATTRS bool IsConnected() const { return false; }
  68   RT_API_ATTRS void Open(OpenStatus, Fortran::common::optional<Action>,
  69       Position, IoErrorHandler &);
  70   RT_API_ATTRS void Predefine(int fd) {}
  71   RT_API_ATTRS void Close(CloseStatus, IoErrorHandler &);
  72   RT_API_ATTRS std::size_t Read(FileOffset, char *, std::size_t minBytes,
  73       std::size_t maxBytes, IoErrorHandler &);
  74   RT_API_ATTRS std::size_t Write(
  75       FileOffset, const char *, std::size_t, IoErrorHandler &);
  76   RT_API_ATTRS void Truncate(FileOffset, IoErrorHandler &);
  77   RT_API_ATTRS int ReadAsynchronously(
  78       FileOffset, char *, std::size_t, IoErrorHandler &);
  79   RT_API_ATTRS int WriteAsynchronously(
  80       FileOffset, const char *, std::size_t, IoErrorHandler &);
  81   RT_API_ATTRS void Wait(int id, IoErrorHandler &);
  82   RT_API_ATTRS void WaitAll(IoErrorHandler &);
  83   RT_API_ATTRS Position InquirePosition() const;
  84 };
  85 #endif // defined(RT_USE_PSEUDO_FILE_UNIT)
  86
  87 #if !defined(RT_USE_PSEUDO_FILE_UNIT)
  88 using OpenFileClass = OpenFile;
  89 using FileFrameClass = FileFrame<ExternalFileUnit>;
  90 #else // defined(RT_USE_PSEUDO_FILE_UNIT)
  91 using OpenFileClass = PseudoOpenFile;
  92 // Use not so big buffer for the pseudo file unit frame.
  93 using FileFrameClass = FileFrame<ExternalFileUnit, 1024>;
  94 #endif // defined(RT_USE_PSEUDO_FILE_UNIT)
  95
  96 class ExternalFileUnit : public ConnectionState,
  97                          public OpenFileClass,
  98                          public FileFrameClass {
  99 public:
 100   static constexpr int maxAsyncIds{64 * 16};
 101
 102   explicit RT_API_ATTRS ExternalFileUnit(int unitNumber)
 103       : unitNumber_{unitNumber} {
 104     isUTF8 = executionEnvironment.defaultUTF8;
 105     for (int j{0}; 64 * j < maxAsyncIds; ++j) {
 106       asyncIdAvailable_[j].set();
 107     }
 108     asyncIdAvailable_[0].reset(0);
 109   }
 110   RT_API_ATTRS ~ExternalFileUnit() {}
 111
 112   RT_API_ATTRS int unitNumber() const { return unitNumber_; }
 113   RT_API_ATTRS bool swapEndianness() const { return swapEndianness_; }
 114   RT_API_ATTRS bool createdForInternalChildIo() const {
 115     return createdForInternalChildIo_;
 116   }
 117
 118   static RT_API_ATTRS ExternalFileUnit *LookUp(int unit);
 119   static RT_API_ATTRS ExternalFileUnit *LookUpOrCreate(
 120       int unit, const Terminator &, bool &wasExtant);
 121   static RT_API_ATTRS ExternalFileUnit *LookUpOrCreateAnonymous(int unit,
 122       Direction, Fortran::common::optional<bool> isUnformatted,
 123       IoErrorHandler &);
 124   static RT_API_ATTRS ExternalFileUnit *LookUp(
 125       const char *path, std::size_t pathLen);
 126   static RT_API_ATTRS ExternalFileUnit &CreateNew(int unit, const Terminator &);
 127   static RT_API_ATTRS ExternalFileUnit *LookUpForClose(int unit);
 128   static RT_API_ATTRS ExternalFileUnit &NewUnit(
 129       const Terminator &, bool forChildIo);
 130   static RT_API_ATTRS void CloseAll(IoErrorHandler &);
 131   static RT_API_ATTRS void FlushAll(IoErrorHandler &);
 132
 133   // Returns true if an existing unit was closed
 134   RT_API_ATTRS bool OpenUnit(Fortran::common::optional<OpenStatus>,
 135       Fortran::common::optional<Action>, Position, OwningPtr<char> &&path,
 136       std::size_t pathLength, Convert, IoErrorHandler &);
 137   RT_API_ATTRS bool OpenAnonymousUnit(Fortran::common::optional<OpenStatus>,
 138       Fortran::common::optional<Action>, Position, Convert, IoErrorHandler &);
 139   RT_API_ATTRS void CloseUnit(CloseStatus, IoErrorHandler &);
 140   RT_API_ATTRS void DestroyClosed();
 141
 142   RT_API_ATTRS Iostat SetDirection(Direction);
 143
 144   template <typename A, typename... X>
 145   RT_API_ATTRS IoStatementState &BeginIoStatement(
 146       const Terminator &terminator, X &&...xs) {
 147     // Take lock_ and hold it until EndIoStatement().
 148 #if USE_PTHREADS
 149     if (!lock_.TakeIfNoDeadlock()) {
 150       terminator.Crash("Recursive I/O attempted on unit %d", unitNumber_);
 151     }
 152 #else
 153     lock_.Take();
 154 #endif
 155     A &state{u_.emplace<A>(std::forward<X>(xs)...)};
 156     if constexpr (!std::is_same_v<A, OpenStatementState>) {
 157       state.mutableModes() = ConnectionState::modes;
 158     }
 159     directAccessRecWasSet_ = false;
 160     io_.emplace(state);
 161     return *io_;
 162   }
 163
 164   RT_API_ATTRS bool Emit(
 165       const char *, std::size_t, std::size_t elementBytes, IoErrorHandler &);
 166   RT_API_ATTRS bool Receive(
 167       char *, std::size_t, std::size_t elementBytes, IoErrorHandler &);
 168   RT_API_ATTRS std::size_t GetNextInputBytes(const char *&, IoErrorHandler &);
 169   RT_API_ATTRS std::size_t ViewBytesInRecord(const char *&, bool forward) const;
 170   RT_API_ATTRS bool BeginReadingRecord(IoErrorHandler &);
 171   RT_API_ATTRS void FinishReadingRecord(IoErrorHandler &);
 172   RT_API_ATTRS bool AdvanceRecord(IoErrorHandler &);
 173   RT_API_ATTRS void BackspaceRecord(IoErrorHandler &);
 174   RT_API_ATTRS void FlushOutput(IoErrorHandler &);
 175   RT_API_ATTRS void FlushIfTerminal(IoErrorHandler &);
 176   RT_API_ATTRS void Endfile(IoErrorHandler &);
 177   RT_API_ATTRS void Rewind(IoErrorHandler &);
 178   RT_API_ATTRS void EndIoStatement();
 179   RT_API_ATTRS bool SetStreamPos(
 180       std::int64_t, IoErrorHandler &); // one-based, for POS=
 181   RT_API_ATTRS bool SetDirectRec(
 182       std::int64_t, IoErrorHandler &); // one-based, for REC=
 183   RT_API_ATTRS std::int64_t InquirePos() const {
 184     // 12.6.2.11 defines POS=1 as the beginning of file
 185     return frameOffsetInFile_ + recordOffsetInFrame_ + positionInRecord + 1;
 186   }
 187
 188   RT_API_ATTRS ChildIo *GetChildIo() { return child_.get(); }
 189   RT_API_ATTRS ChildIo &PushChildIo(IoStatementState &);
 190   RT_API_ATTRS void PopChildIo(ChildIo &);
 191
 192   RT_API_ATTRS int GetAsynchronousId(IoErrorHandler &);
 193   RT_API_ATTRS bool Wait(int);
 194
 195 private:
 196   static RT_API_ATTRS UnitMap &CreateUnitMap();
 197   static RT_API_ATTRS UnitMap &GetUnitMap();
 198   RT_API_ATTRS const char *FrameNextInput(IoErrorHandler &, std::size_t);
 199   RT_API_ATTRS void SetPosition(std::int64_t, IoErrorHandler &); // zero-based
 200   RT_API_ATTRS void BeginSequentialVariableUnformattedInputRecord(
 201       IoErrorHandler &);
 202   RT_API_ATTRS void BeginVariableFormattedInputRecord(IoErrorHandler &);
 203   RT_API_ATTRS void BackspaceFixedRecord(IoErrorHandler &);
 204   RT_API_ATTRS void BackspaceVariableUnformattedRecord(IoErrorHandler &);
 205   RT_API_ATTRS void BackspaceVariableFormattedRecord(IoErrorHandler &);
 206   RT_API_ATTRS bool SetVariableFormattedRecordLength();
 207   RT_API_ATTRS void DoImpliedEndfile(IoErrorHandler &);
 208   template <bool ANY_DIR = true, Direction DIR = Direction::Output>
 209   RT_API_ATTRS void DoEndfile(IoErrorHandler &);
 210   RT_API_ATTRS void CommitWrites();
 211   RT_API_ATTRS bool CheckDirectAccess(IoErrorHandler &);
 212   RT_API_ATTRS void HitEndOnRead(IoErrorHandler &);
 213   RT_API_ATTRS std::int32_t ReadHeaderOrFooter(std::int64_t frameOffset);
 214
 215   Lock lock_;
 216
 217   int unitNumber_{-1};
 218   Direction direction_{Direction::Output};
 219   bool impliedEndfile_{false}; // sequential/stream output has taken place
 220   bool beganReadingRecord_{false};
 221   bool anyWriteSinceLastPositioning_{false};
 222   bool directAccessRecWasSet_{false}; // REC= appeared
 223   // Subtle: The beginning of the frame can't be allowed to advance
 224   // during a single list-directed READ due to the possibility of a
 225   // multi-record CHARACTER value with a "r*" repeat count.  So we
 226   // manage the frame and the current record therein separately.
 227   std::int64_t frameOffsetInFile_{0};
 228   std::size_t recordOffsetInFrame_{0}; // of currentRecordNumber
 229   bool swapEndianness_{false};
 230   bool createdForInternalChildIo_{false};
 231   common::BitSet<64> asyncIdAvailable_[maxAsyncIds / 64];
 232
 233   // When a synchronous I/O statement is in progress on this unit, holds its
 234   // state.
 235   std::variant<std::monostate, OpenStatementState, CloseStatementState,
 236       ExternalFormattedIoStatementState<Direction::Output>,
 237       ExternalFormattedIoStatementState<Direction::Input>,
 238       ExternalListIoStatementState<Direction::Output>,
 239       ExternalListIoStatementState<Direction::Input>,
 240       ExternalUnformattedIoStatementState<Direction::Output>,
 241       ExternalUnformattedIoStatementState<Direction::Input>, InquireUnitState,
 242       ExternalMiscIoStatementState, ErroneousIoStatementState>
 243       u_;
 244
 245   // Points to the active alternative (if any) in u_ for use as a Cookie
 246   Fortran::common::optional<IoStatementState> io_;
 247
 248   // A stack of child I/O pseudo-units for defined I/O that have this
 249   // unit number.
 250   OwningPtr<ChildIo> child_;
 251 };
 252
 253 // A pseudo-unit for child I/O statements in defined I/O subroutines;
 254 // it forwards operations to the parent I/O statement, which might also
 255 // be a child I/O statement.
 256 class ChildIo {
 257 public:
 258   RT_API_ATTRS ChildIo(IoStatementState &parent, OwningPtr<ChildIo> &&previous)
 259       : parent_{parent}, previous_{std::move(previous)} {}
 260
 261   RT_API_ATTRS IoStatementState &parent() const { return parent_; }
 262
 263   RT_API_ATTRS void EndIoStatement();
 264
 265   template <typename A, typename... X>
 266   RT_API_ATTRS IoStatementState &BeginIoStatement(X &&...xs) {
 267     A &state{u_.emplace<A>(std::forward<X>(xs)...)};
 268     io_.emplace(state);
 269     return *io_;
 270   }
 271
 272   RT_API_ATTRS OwningPtr<ChildIo> AcquirePrevious() {
 273     return std::move(previous_);
 274   }
 275
 276   RT_API_ATTRS Iostat CheckFormattingAndDirection(bool unformatted, Direction);
 277
 278 private:
 279   IoStatementState &parent_;
 280   OwningPtr<ChildIo> previous_;
 281   std::variant<std::monostate,
 282       ChildFormattedIoStatementState<Direction::Output>,
 283       ChildFormattedIoStatementState<Direction::Input>,
 284       ChildListIoStatementState<Direction::Output>,
 285       ChildListIoStatementState<Direction::Input>,
 286       ChildUnformattedIoStatementState<Direction::Output>,
 287       ChildUnformattedIoStatementState<Direction::Input>, InquireUnitState,
 288       ErroneousIoStatementState, ExternalMiscIoStatementState>
 289       u_;
 290   Fortran::common::optional<IoStatementState> io_;
 291 };
 292
 293 } // namespace Fortran::runtime::io
 294 #endif // FORTRAN_RUNTIME_IO_UNIT_H_