lib/Support/raw_ostream.cpp

   1 //===--- raw_ostream.cpp - Implement the raw_ostream classes --------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This implements support for bulk buffered stream output.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Support/raw_ostream.h"
  15 #include "llvm/Support/Format.h"
  16 #include "llvm/System/Program.h"
  17 #include "llvm/System/Process.h"
  18 #include "llvm/ADT/SmallVector.h"
  19 #include "llvm/Config/config.h"
  20 #include "llvm/Support/Compiler.h"
  21 #include "llvm/Support/ErrorHandling.h"
  22 #include "llvm/ADT/STLExtras.h"
  23 #include "llvm/ADT/StringExtras.h"
  24 #include <sys/stat.h>
  25 #include <sys/types.h>
  26
  27 #if defined(HAVE_UNISTD_H)
  28 # include <unistd.h>
  29 #endif
  30 #if defined(HAVE_FCNTL_H)
  31 # include <fcntl.h>
  32 #endif
  33
  34 #if defined(_MSC_VER)
  35 #include <io.h>
  36 #include <fcntl.h>
  37 #ifndef STDIN_FILENO
  38 # define STDIN_FILENO 0
  39 #endif
  40 #ifndef STDOUT_FILENO
  41 # define STDOUT_FILENO 1
  42 #endif
  43 #ifndef STDERR_FILENO
  44 # define STDERR_FILENO 2
  45 #endif
  46 #endif
  47
  48 using namespace llvm;
  49
  50 raw_ostream::~raw_ostream() {
  51   // raw_ostream's subclasses should take care to flush the buffer
  52   // in their destructors.
  53   assert(OutBufCur == OutBufStart &&
  54          "raw_ostream destructor called with non-empty buffer!");
  55
  56   if (BufferMode == InternalBuffer)
  57     delete [] OutBufStart;
  58
  59   // If there are any pending errors, report them now. Clients wishing
  60   // to avoid llvm_report_error calls should check for errors with
  61   // has_error() and clear the error flag with clear_error() before
  62   // destructing raw_ostream objects which may have errors.
  63   if (Error)
  64     llvm_report_error("IO failure on output stream.");
  65 }
  66
  67 // An out of line virtual method to provide a home for the class vtable.
  68 void raw_ostream::handle() {}
  69
  70 size_t raw_ostream::preferred_buffer_size() {
  71   // BUFSIZ is intended to be a reasonable default.
  72   return BUFSIZ;
  73 }
  74
  75 void raw_ostream::SetBuffered() {
  76   // Ask the subclass to determine an appropriate buffer size.
  77   if (size_t Size = preferred_buffer_size())
  78     SetBufferSize(Size);
  79   else
  80     // It may return 0, meaning this stream should be unbuffered.
  81     SetUnbuffered();
  82 }
  83
  84 void raw_ostream::SetBufferAndMode(char *BufferStart, size_t Size,
  85                                     BufferKind Mode) {
  86   assert(((Mode == Unbuffered && BufferStart == 0 && Size == 0) ||
  87           (Mode != Unbuffered && BufferStart && Size >= 64)) &&
  88          "stream must be unbuffered, or have >= 64 bytes of buffer");
  89   // Make sure the current buffer is free of content (we can't flush here; the
  90   // child buffer management logic will be in write_impl).
  91   assert(GetNumBytesInBuffer() == 0 && "Current buffer is non-empty!");
  92
  93   if (BufferMode == InternalBuffer)
  94     delete [] OutBufStart;
  95   OutBufStart = BufferStart;
  96   OutBufEnd = OutBufStart+Size;
  97   OutBufCur = OutBufStart;
  98   BufferMode = Mode;
  99
 100   assert(OutBufStart <= OutBufEnd && "Invalid size!");
 101 }
 102
 103 raw_ostream &raw_ostream::operator<<(unsigned long N) {
 104   // Zero is a special case.
 105   if (N == 0)
 106     return *this << '0';
 107
 108   char NumberBuffer[20];
 109   char *EndPtr = NumberBuffer+sizeof(NumberBuffer);
 110   char *CurPtr = EndPtr;
 111
 112   while (N) {
 113     *--CurPtr = '0' + char(N % 10);
 114     N /= 10;
 115   }
 116   return write(CurPtr, EndPtr-CurPtr);
 117 }
 118
 119 raw_ostream &raw_ostream::operator<<(long N) {
 120   if (N <  0) {
 121     *this << '-';
 122     N = -N;
 123   }
 124
 125   return this->operator<<(static_cast<unsigned long>(N));
 126 }
 127
 128 raw_ostream &raw_ostream::operator<<(unsigned long long N) {
 129   // Output using 32-bit div/mod when possible.
 130   if (N == static_cast<unsigned long>(N))
 131     return this->operator<<(static_cast<unsigned long>(N));
 132
 133   char NumberBuffer[20];
 134   char *EndPtr = NumberBuffer+sizeof(NumberBuffer);
 135   char *CurPtr = EndPtr;
 136
 137   while (N) {
 138     *--CurPtr = '0' + char(N % 10);
 139     N /= 10;
 140   }
 141   return write(CurPtr, EndPtr-CurPtr);
 142 }
 143
 144 raw_ostream &raw_ostream::operator<<(long long N) {
 145   if (N <  0) {
 146     *this << '-';
 147     N = -N;
 148   }
 149
 150   return this->operator<<(static_cast<unsigned long long>(N));
 151 }
 152
 153 raw_ostream &raw_ostream::write_hex(unsigned long long N) {
 154   // Zero is a special case.
 155   if (N == 0)
 156     return *this << '0';
 157
 158   char NumberBuffer[20];
 159   char *EndPtr = NumberBuffer+sizeof(NumberBuffer);
 160   char *CurPtr = EndPtr;
 161
 162   while (N) {
 163     uintptr_t x = N % 16;
 164     *--CurPtr = (x < 10 ? '0' + x : 'a' + x - 10);
 165     N /= 16;
 166   }
 167
 168   return write(CurPtr, EndPtr-CurPtr);
 169 }
 170
 171 raw_ostream &raw_ostream::operator<<(const void *P) {
 172   *this << '0' << 'x';
 173
 174   return write_hex((uintptr_t) P);
 175 }
 176
 177 raw_ostream &raw_ostream::operator<<(double N) {
 178   this->operator<<(ftostr(N));
 179   return *this;
 180 }
 181
 182
 183
 184 void raw_ostream::flush_nonempty() {
 185   assert(OutBufCur > OutBufStart && "Invalid call to flush_nonempty.");
 186   size_t Length = OutBufCur - OutBufStart;
 187   OutBufCur = OutBufStart;
 188   write_impl(OutBufStart, Length);
 189 }
 190
 191 raw_ostream &raw_ostream::write(unsigned char C) {
 192   // Group exceptional cases into a single branch.
 193   if (BUILTIN_EXPECT(OutBufCur >= OutBufEnd, false)) {
 194     if (BUILTIN_EXPECT(!OutBufStart, false)) {
 195       if (BufferMode == Unbuffered) {
 196         write_impl(reinterpret_cast<char*>(&C), 1);
 197         return *this;
 198       }
 199       // Set up a buffer and start over.
 200       SetBuffered();
 201       return write(C);
 202     }
 203
 204     flush_nonempty();
 205   }
 206
 207   *OutBufCur++ = C;
 208   return *this;
 209 }
 210
 211 raw_ostream &raw_ostream::write(const char *Ptr, size_t Size) {
 212   // Group exceptional cases into a single branch.
 213   if (BUILTIN_EXPECT(OutBufCur+Size > OutBufEnd, false)) {
 214     if (BUILTIN_EXPECT(!OutBufStart, false)) {
 215       if (BufferMode == Unbuffered) {
 216         write_impl(Ptr, Size);
 217         return *this;
 218       }
 219       // Set up a buffer and start over.
 220       SetBuffered();
 221       return write(Ptr, Size);
 222     }
 223
 224     // Write out the data in buffer-sized blocks until the remainder
 225     // fits within the buffer.
 226     do {
 227       size_t NumBytes = OutBufEnd - OutBufCur;
 228       copy_to_buffer(Ptr, NumBytes);
 229       flush_nonempty();
 230       Ptr += NumBytes;
 231       Size -= NumBytes;
 232     } while (OutBufCur+Size > OutBufEnd);
 233   }
 234
 235   copy_to_buffer(Ptr, Size);
 236
 237   return *this;
 238 }
 239
 240 void raw_ostream::copy_to_buffer(const char *Ptr, size_t Size) {
 241   assert(Size <= size_t(OutBufEnd - OutBufCur) && "Buffer overrun!");
 242
 243   // Handle short strings specially, memcpy isn't very good at very short
 244   // strings.
 245   switch (Size) {
 246   case 4: OutBufCur[3] = Ptr[3]; // FALL THROUGH
 247   case 3: OutBufCur[2] = Ptr[2]; // FALL THROUGH
 248   case 2: OutBufCur[1] = Ptr[1]; // FALL THROUGH
 249   case 1: OutBufCur[0] = Ptr[0]; // FALL THROUGH
 250   case 0: break;
 251   default:
 252     memcpy(OutBufCur, Ptr, Size);
 253     break;
 254   }
 255
 256   OutBufCur += Size;
 257 }
 258
 259 // Formatted output.
 260 raw_ostream &raw_ostream::operator<<(const format_object_base &Fmt) {
 261   // If we have more than a few bytes left in our output buffer, try
 262   // formatting directly onto its end.
 263   size_t NextBufferSize = 127;
 264   size_t BufferBytesLeft = OutBufEnd - OutBufCur;
 265   if (BufferBytesLeft > 3) {
 266     size_t BytesUsed = Fmt.print(OutBufCur, BufferBytesLeft);
 267
 268     // Common case is that we have plenty of space.
 269     if (BytesUsed <= BufferBytesLeft) {
 270       OutBufCur += BytesUsed;
 271       return *this;
 272     }
 273
 274     // Otherwise, we overflowed and the return value tells us the size to try
 275     // again with.
 276     NextBufferSize = BytesUsed;
 277   }
 278
 279   // If we got here, we didn't have enough space in the output buffer for the
 280   // string.  Try printing into a SmallVector that is resized to have enough
 281   // space.  Iterate until we win.
 282   SmallVector<char, 128> V;
 283
 284   while (1) {
 285     V.resize(NextBufferSize);
 286
 287     // Try formatting into the SmallVector.
 288     size_t BytesUsed = Fmt.print(V.data(), NextBufferSize);
 289
 290     // If BytesUsed fit into the vector, we win.
 291     if (BytesUsed <= NextBufferSize)
 292       return write(V.data(), BytesUsed);
 293
 294     // Otherwise, try again with a new size.
 295     assert(BytesUsed > NextBufferSize && "Didn't grow buffer!?");
 296     NextBufferSize = BytesUsed;
 297   }
 298 }
 299
 300 /// indent - Insert 'NumSpaces' spaces.
 301 raw_ostream &raw_ostream::indent(unsigned NumSpaces) {
 302   static const char Spaces[] = "                                "
 303                                "                                "
 304                                "                ";
 305
 306   // Usually the indentation is small, handle it with a fastpath.
 307   if (NumSpaces < array_lengthof(Spaces))
 308     return write(Spaces, NumSpaces);
 309
 310   while (NumSpaces) {
 311     unsigned NumToWrite = std::min(NumSpaces,
 312                                    (unsigned)array_lengthof(Spaces)-1);
 313     write(Spaces, NumToWrite);
 314     NumSpaces -= NumToWrite;
 315   }
 316   return *this;
 317 }
 318
 319
 320 //===----------------------------------------------------------------------===//
 321 //  Formatted Output
 322 //===----------------------------------------------------------------------===//
 323
 324 // Out of line virtual method.
 325 void format_object_base::home() {
 326 }
 327
 328 //===----------------------------------------------------------------------===//
 329 //  raw_fd_ostream
 330 //===----------------------------------------------------------------------===//
 331
 332 /// raw_fd_ostream - Open the specified file for writing. If an error
 333 /// occurs, information about the error is put into ErrorInfo, and the
 334 /// stream should be immediately destroyed; the string will be empty
 335 /// if no error occurred.
 336 raw_fd_ostream::raw_fd_ostream(const char *Filename, std::string &ErrorInfo,
 337                                unsigned Flags) : pos(0) {
 338   // Verify that we don't have both "append" and "excl".
 339   assert((!(Flags & F_Excl) || !(Flags & F_Append)) &&
 340          "Cannot specify both 'excl' and 'append' file creation flags!");
 341
 342   ErrorInfo.clear();
 343
 344   // Handle "-" as stdout.
 345   if (Filename[0] == '-' && Filename[1] == 0) {
 346     FD = STDOUT_FILENO;
 347     // If user requested binary then put stdout into binary mode if
 348     // possible.
 349     if (Flags & F_Binary)
 350       sys::Program::ChangeStdoutToBinary();
 351     ShouldClose = false;
 352     return;
 353   }
 354
 355   int OpenFlags = O_WRONLY|O_CREAT;
 356 #ifdef O_BINARY
 357   if (Flags & F_Binary)
 358     OpenFlags |= O_BINARY;
 359 #endif
 360
 361   if (Flags & F_Append)
 362     OpenFlags |= O_APPEND;
 363   else
 364     OpenFlags |= O_TRUNC;
 365   if (Flags & F_Excl)
 366     OpenFlags |= O_EXCL;
 367
 368   FD = open(Filename, OpenFlags, 0664);
 369   if (FD < 0) {
 370     ErrorInfo = "Error opening output file '" + std::string(Filename) + "'";
 371     ShouldClose = false;
 372   } else {
 373     ShouldClose = true;
 374   }
 375 }
 376
 377 raw_fd_ostream::~raw_fd_ostream() {
 378   if (FD < 0) return;
 379   flush();
 380   if (ShouldClose)
 381     if (::close(FD) != 0)
 382       error_detected();
 383 }
 384
 385
 386 void raw_fd_ostream::write_impl(const char *Ptr, size_t Size) {
 387   assert (FD >= 0 && "File already closed.");
 388   pos += Size;
 389   if (::write(FD, Ptr, Size) != (ssize_t) Size)
 390     error_detected();
 391 }
 392
 393 void raw_fd_ostream::close() {
 394   assert (ShouldClose);
 395   ShouldClose = false;
 396   flush();
 397   if (::close(FD) != 0)
 398     error_detected();
 399   FD = -1;
 400 }
 401
 402 uint64_t raw_fd_ostream::seek(uint64_t off) {
 403   flush();
 404   pos = ::lseek(FD, off, SEEK_SET);
 405   if (pos != off)
 406     error_detected();
 407   return pos;
 408 }
 409
 410 size_t raw_fd_ostream::preferred_buffer_size() {
 411 #if !defined(_MSC_VER) && !defined(__MINGW32__) // Windows has no st_blksize.
 412   assert(FD >= 0 && "File not yet open!");
 413   struct stat statbuf;
 414   if (fstat(FD, &statbuf) == 0) {
 415     // If this is a terminal, don't use buffering. Line buffering
 416     // would be a more traditional thing to do, but it's not worth
 417     // the complexity.
 418     if (S_ISCHR(statbuf.st_mode) && isatty(FD))
 419       return 0;
 420     // Return the preferred block size.
 421     return statbuf.st_blksize;
 422   }
 423   error_detected();
 424 #endif
 425   return raw_ostream::preferred_buffer_size();
 426 }
 427
 428 raw_ostream &raw_fd_ostream::changeColor(enum Colors colors, bool bold,
 429                                          bool bg) {
 430   if (sys::Process::ColorNeedsFlush())
 431     flush();
 432   const char *colorcode =
 433     (colors == SAVEDCOLOR) ? sys::Process::OutputBold(bg)
 434     : sys::Process::OutputColor(colors, bold, bg);
 435   if (colorcode) {
 436     size_t len = strlen(colorcode);
 437     write(colorcode, len);
 438     // don't account colors towards output characters
 439     pos -= len;
 440   }
 441   return *this;
 442 }
 443
 444 raw_ostream &raw_fd_ostream::resetColor() {
 445   if (sys::Process::ColorNeedsFlush())
 446     flush();
 447   const char *colorcode = sys::Process::ResetColor();
 448   if (colorcode) {
 449     size_t len = strlen(colorcode);
 450     write(colorcode, len);
 451     // don't account colors towards output characters
 452     pos -= len;
 453   }
 454   return *this;
 455 }
 456
 457 //===----------------------------------------------------------------------===//
 458 //  raw_stdout/err_ostream
 459 //===----------------------------------------------------------------------===//
 460
 461 // Set buffer settings to model stdout and stderr behavior.
 462 // Set standard error to be unbuffered by default.
 463 raw_stdout_ostream::raw_stdout_ostream():raw_fd_ostream(STDOUT_FILENO, false) {}
 464 raw_stderr_ostream::raw_stderr_ostream():raw_fd_ostream(STDERR_FILENO, false,
 465                                                         true) {}
 466
 467 // An out of line virtual method to provide a home for the class vtable.
 468 void raw_stdout_ostream::handle() {}
 469 void raw_stderr_ostream::handle() {}
 470
 471 /// outs() - This returns a reference to a raw_ostream for standard output.
 472 /// Use it like: outs() << "foo" << "bar";
 473 raw_ostream &llvm::outs() {
 474   static raw_stdout_ostream S;
 475   return S;
 476 }
 477
 478 /// errs() - This returns a reference to a raw_ostream for standard error.
 479 /// Use it like: errs() << "foo" << "bar";
 480 raw_ostream &llvm::errs() {
 481   static raw_stderr_ostream S;
 482   return S;
 483 }
 484
 485 /// nulls() - This returns a reference to a raw_ostream which discards output.
 486 raw_ostream &llvm::nulls() {
 487   static raw_null_ostream S;
 488   return S;
 489 }
 490
 491
 492 //===----------------------------------------------------------------------===//
 493 //  raw_string_ostream
 494 //===----------------------------------------------------------------------===//
 495
 496 raw_string_ostream::~raw_string_ostream() {
 497   flush();
 498 }
 499
 500 void raw_string_ostream::write_impl(const char *Ptr, size_t Size) {
 501   OS.append(Ptr, Size);
 502 }
 503
 504 //===----------------------------------------------------------------------===//
 505 //  raw_svector_ostream
 506 //===----------------------------------------------------------------------===//
 507
 508 // The raw_svector_ostream implementation uses the SmallVector itself as the
 509 // buffer for the raw_ostream. We guarantee that the raw_ostream buffer is
 510 // always pointing past the end of the vector, but within the vector
 511 // capacity. This allows raw_ostream to write directly into the correct place,
 512 // and we only need to set the vector size when the data is flushed.
 513
 514 raw_svector_ostream::raw_svector_ostream(SmallVectorImpl<char> &O) : OS(O) {
 515   // Set up the initial external buffer. We make sure that the buffer has at
 516   // least 128 bytes free; raw_ostream itself only requires 64, but we want to
 517   // make sure that we don't grow the buffer unnecessarily on destruction (when
 518   // the data is flushed). See the FIXME below.
 519   OS.reserve(OS.size() + 128);
 520   SetBuffer(OS.end(), OS.capacity() - OS.size());
 521 }
 522
 523 raw_svector_ostream::~raw_svector_ostream() {
 524   // FIXME: Prevent resizing during this flush().
 525   flush();
 526 }
 527
 528 void raw_svector_ostream::write_impl(const char *Ptr, size_t Size) {
 529   assert(Ptr == OS.end() && OS.size() + Size <= OS.capacity() &&
 530          "Invalid write_impl() call!");
 531
 532   // We don't need to copy the bytes, just commit the bytes to the
 533   // SmallVector.
 534   OS.set_size(OS.size() + Size);
 535
 536   // Grow the vector if necessary.
 537   if (OS.capacity() - OS.size() < 64)
 538     OS.reserve(OS.capacity() * 2);
 539
 540   // Update the buffer position.
 541   SetBuffer(OS.end(), OS.capacity() - OS.size());
 542 }
 543
 544 uint64_t raw_svector_ostream::current_pos() { return OS.size(); }
 545
 546 StringRef raw_svector_ostream::str() {
 547   flush();
 548   return StringRef(OS.begin(), OS.size());
 549 }
 550
 551 //===----------------------------------------------------------------------===//
 552 //  raw_null_ostream
 553 //===----------------------------------------------------------------------===//
 554
 555 raw_null_ostream::~raw_null_ostream() {
 556 #ifndef NDEBUG
 557   // ~raw_ostream asserts that the buffer is empty. This isn't necessary
 558   // with raw_null_ostream, but it's better to have raw_null_ostream follow
 559   // the rules than to change the rules just for raw_null_ostream.
 560   flush();
 561 #endif
 562 }
 563
 564 void raw_null_ostream::write_impl(const char *Ptr, size_t Size) {
 565 }
 566
 567 uint64_t raw_null_ostream::current_pos() {
 568   return 0;
 569 }