raw_ostream.h revision 239462
1//===--- raw_ostream.h - Raw output stream ----------------------*- C++ -*-===// 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 file defines the raw_ostream class. 11// 12//===----------------------------------------------------------------------===// 13 14#ifndef LLVM_SUPPORT_RAW_OSTREAM_H 15#define LLVM_SUPPORT_RAW_OSTREAM_H 16 17#include "llvm/ADT/StringRef.h" 18#include "llvm/Support/DataTypes.h" 19 20namespace llvm { 21 class format_object_base; 22 template <typename T> 23 class SmallVectorImpl; 24 25/// raw_ostream - This class implements an extremely fast bulk output stream 26/// that can *only* output to a stream. It does not support seeking, reopening, 27/// rewinding, line buffered disciplines etc. It is a simple buffer that outputs 28/// a chunk at a time. 29class raw_ostream { 30private: 31 // Do not implement. raw_ostream is noncopyable. 32 void operator=(const raw_ostream &); 33 raw_ostream(const raw_ostream &); 34 35 /// The buffer is handled in such a way that the buffer is 36 /// uninitialized, unbuffered, or out of space when OutBufCur >= 37 /// OutBufEnd. Thus a single comparison suffices to determine if we 38 /// need to take the slow path to write a single character. 39 /// 40 /// The buffer is in one of three states: 41 /// 1. Unbuffered (BufferMode == Unbuffered) 42 /// 1. Uninitialized (BufferMode != Unbuffered && OutBufStart == 0). 43 /// 2. Buffered (BufferMode != Unbuffered && OutBufStart != 0 && 44 /// OutBufEnd - OutBufStart >= 1). 45 /// 46 /// If buffered, then the raw_ostream owns the buffer if (BufferMode == 47 /// InternalBuffer); otherwise the buffer has been set via SetBuffer and is 48 /// managed by the subclass. 49 /// 50 /// If a subclass installs an external buffer using SetBuffer then it can wait 51 /// for a \see write_impl() call to handle the data which has been put into 52 /// this buffer. 53 char *OutBufStart, *OutBufEnd, *OutBufCur; 54 55 enum BufferKind { 56 Unbuffered = 0, 57 InternalBuffer, 58 ExternalBuffer 59 } BufferMode; 60 61public: 62 // color order matches ANSI escape sequence, don't change 63 enum Colors { 64 BLACK=0, 65 RED, 66 GREEN, 67 YELLOW, 68 BLUE, 69 MAGENTA, 70 CYAN, 71 WHITE, 72 SAVEDCOLOR 73 }; 74 75 explicit raw_ostream(bool unbuffered=false) 76 : BufferMode(unbuffered ? Unbuffered : InternalBuffer) { 77 // Start out ready to flush. 78 OutBufStart = OutBufEnd = OutBufCur = 0; 79 } 80 81 virtual ~raw_ostream(); 82 83 /// tell - Return the current offset with the file. 84 uint64_t tell() const { return current_pos() + GetNumBytesInBuffer(); } 85 86 //===--------------------------------------------------------------------===// 87 // Configuration Interface 88 //===--------------------------------------------------------------------===// 89 90 /// SetBuffered - Set the stream to be buffered, with an automatically 91 /// determined buffer size. 92 void SetBuffered(); 93 94 /// SetBufferSize - Set the stream to be buffered, using the 95 /// specified buffer size. 96 void SetBufferSize(size_t Size) { 97 flush(); 98 SetBufferAndMode(new char[Size], Size, InternalBuffer); 99 } 100 101 size_t GetBufferSize() const { 102 // If we're supposed to be buffered but haven't actually gotten around 103 // to allocating the buffer yet, return the value that would be used. 104 if (BufferMode != Unbuffered && OutBufStart == 0) 105 return preferred_buffer_size(); 106 107 // Otherwise just return the size of the allocated buffer. 108 return OutBufEnd - OutBufStart; 109 } 110 111 /// SetUnbuffered - Set the stream to be unbuffered. When 112 /// unbuffered, the stream will flush after every write. This routine 113 /// will also flush the buffer immediately when the stream is being 114 /// set to unbuffered. 115 void SetUnbuffered() { 116 flush(); 117 SetBufferAndMode(0, 0, Unbuffered); 118 } 119 120 size_t GetNumBytesInBuffer() const { 121 return OutBufCur - OutBufStart; 122 } 123 124 //===--------------------------------------------------------------------===// 125 // Data Output Interface 126 //===--------------------------------------------------------------------===// 127 128 void flush() { 129 if (OutBufCur != OutBufStart) 130 flush_nonempty(); 131 } 132 133 raw_ostream &operator<<(char C) { 134 if (OutBufCur >= OutBufEnd) 135 return write(C); 136 *OutBufCur++ = C; 137 return *this; 138 } 139 140 raw_ostream &operator<<(unsigned char C) { 141 if (OutBufCur >= OutBufEnd) 142 return write(C); 143 *OutBufCur++ = C; 144 return *this; 145 } 146 147 raw_ostream &operator<<(signed char C) { 148 if (OutBufCur >= OutBufEnd) 149 return write(C); 150 *OutBufCur++ = C; 151 return *this; 152 } 153 154 raw_ostream &operator<<(StringRef Str) { 155 // Inline fast path, particularly for strings with a known length. 156 size_t Size = Str.size(); 157 158 // Make sure we can use the fast path. 159 if (OutBufCur+Size > OutBufEnd) 160 return write(Str.data(), Size); 161 162 memcpy(OutBufCur, Str.data(), Size); 163 OutBufCur += Size; 164 return *this; 165 } 166 167 raw_ostream &operator<<(const char *Str) { 168 // Inline fast path, particularly for constant strings where a sufficiently 169 // smart compiler will simplify strlen. 170 171 return this->operator<<(StringRef(Str)); 172 } 173 174 raw_ostream &operator<<(const std::string &Str) { 175 // Avoid the fast path, it would only increase code size for a marginal win. 176 return write(Str.data(), Str.length()); 177 } 178 179 raw_ostream &operator<<(unsigned long N); 180 raw_ostream &operator<<(long N); 181 raw_ostream &operator<<(unsigned long long N); 182 raw_ostream &operator<<(long long N); 183 raw_ostream &operator<<(const void *P); 184 raw_ostream &operator<<(unsigned int N) { 185 return this->operator<<(static_cast<unsigned long>(N)); 186 } 187 188 raw_ostream &operator<<(int N) { 189 return this->operator<<(static_cast<long>(N)); 190 } 191 192 raw_ostream &operator<<(double N); 193 194 /// write_hex - Output \arg N in hexadecimal, without any prefix or padding. 195 raw_ostream &write_hex(unsigned long long N); 196 197 /// write_escaped - Output \arg Str, turning '\\', '\t', '\n', '"', and 198 /// anything that doesn't satisfy std::isprint into an escape sequence. 199 raw_ostream &write_escaped(StringRef Str, bool UseHexEscapes = false); 200 201 raw_ostream &write(unsigned char C); 202 raw_ostream &write(const char *Ptr, size_t Size); 203 204 // Formatted output, see the format() function in Support/Format.h. 205 raw_ostream &operator<<(const format_object_base &Fmt); 206 207 /// indent - Insert 'NumSpaces' spaces. 208 raw_ostream &indent(unsigned NumSpaces); 209 210 211 /// Changes the foreground color of text that will be output from this point 212 /// forward. 213 /// @param colors ANSI color to use, the special SAVEDCOLOR can be used to 214 /// change only the bold attribute, and keep colors untouched 215 /// @param bold bold/brighter text, default false 216 /// @param bg if true change the background, default: change foreground 217 /// @returns itself so it can be used within << invocations 218 virtual raw_ostream &changeColor(enum Colors, bool = false, bool = false) { 219 return *this; } 220 221 /// Resets the colors to terminal defaults. Call this when you are done 222 /// outputting colored text, or before program exit. 223 virtual raw_ostream &resetColor() { return *this; } 224 225 /// Reverses the forground and background colors. 226 virtual raw_ostream &reverseColor() { return *this; } 227 228 /// This function determines if this stream is connected to a "tty" or 229 /// "console" window. That is, the output would be displayed to the user 230 /// rather than being put on a pipe or stored in a file. 231 virtual bool is_displayed() const { return false; } 232 233 /// This function determines if this stream is displayed and supports colors. 234 virtual bool has_colors() const { return is_displayed(); } 235 236 //===--------------------------------------------------------------------===// 237 // Subclass Interface 238 //===--------------------------------------------------------------------===// 239 240private: 241 /// write_impl - The is the piece of the class that is implemented 242 /// by subclasses. This writes the \args Size bytes starting at 243 /// \arg Ptr to the underlying stream. 244 /// 245 /// This function is guaranteed to only be called at a point at which it is 246 /// safe for the subclass to install a new buffer via SetBuffer. 247 /// 248 /// \arg Ptr - The start of the data to be written. For buffered streams this 249 /// is guaranteed to be the start of the buffer. 250 /// \arg Size - The number of bytes to be written. 251 /// 252 /// \invariant { Size > 0 } 253 virtual void write_impl(const char *Ptr, size_t Size) = 0; 254 255 // An out of line virtual method to provide a home for the class vtable. 256 virtual void handle(); 257 258 /// current_pos - Return the current position within the stream, not 259 /// counting the bytes currently in the buffer. 260 virtual uint64_t current_pos() const = 0; 261 262protected: 263 /// SetBuffer - Use the provided buffer as the raw_ostream buffer. This is 264 /// intended for use only by subclasses which can arrange for the output to go 265 /// directly into the desired output buffer, instead of being copied on each 266 /// flush. 267 void SetBuffer(char *BufferStart, size_t Size) { 268 SetBufferAndMode(BufferStart, Size, ExternalBuffer); 269 } 270 271 /// preferred_buffer_size - Return an efficient buffer size for the 272 /// underlying output mechanism. 273 virtual size_t preferred_buffer_size() const; 274 275 /// getBufferStart - Return the beginning of the current stream buffer, or 0 276 /// if the stream is unbuffered. 277 const char *getBufferStart() const { return OutBufStart; } 278 279 //===--------------------------------------------------------------------===// 280 // Private Interface 281 //===--------------------------------------------------------------------===// 282private: 283 /// SetBufferAndMode - Install the given buffer and mode. 284 void SetBufferAndMode(char *BufferStart, size_t Size, BufferKind Mode); 285 286 /// flush_nonempty - Flush the current buffer, which is known to be 287 /// non-empty. This outputs the currently buffered data and resets 288 /// the buffer to empty. 289 void flush_nonempty(); 290 291 /// copy_to_buffer - Copy data into the buffer. Size must not be 292 /// greater than the number of unused bytes in the buffer. 293 void copy_to_buffer(const char *Ptr, size_t Size); 294}; 295 296//===----------------------------------------------------------------------===// 297// File Output Streams 298//===----------------------------------------------------------------------===// 299 300/// raw_fd_ostream - A raw_ostream that writes to a file descriptor. 301/// 302class raw_fd_ostream : public raw_ostream { 303 int FD; 304 bool ShouldClose; 305 306 /// Error This flag is true if an error of any kind has been detected. 307 /// 308 bool Error; 309 310 /// Controls whether the stream should attempt to use atomic writes, when 311 /// possible. 312 bool UseAtomicWrites; 313 314 uint64_t pos; 315 316 /// write_impl - See raw_ostream::write_impl. 317 virtual void write_impl(const char *Ptr, size_t Size); 318 319 /// current_pos - Return the current position within the stream, not 320 /// counting the bytes currently in the buffer. 321 virtual uint64_t current_pos() const { return pos; } 322 323 /// preferred_buffer_size - Determine an efficient buffer size. 324 virtual size_t preferred_buffer_size() const; 325 326 /// error_detected - Set the flag indicating that an output error has 327 /// been encountered. 328 void error_detected() { Error = true; } 329 330public: 331 332 enum { 333 /// F_Excl - When opening a file, this flag makes raw_fd_ostream 334 /// report an error if the file already exists. 335 F_Excl = 1, 336 337 /// F_Append - When opening a file, if it already exists append to the 338 /// existing file instead of returning an error. This may not be specified 339 /// with F_Excl. 340 F_Append = 2, 341 342 /// F_Binary - The file should be opened in binary mode on platforms that 343 /// make this distinction. 344 F_Binary = 4 345 }; 346 347 /// raw_fd_ostream - Open the specified file for writing. If an error occurs, 348 /// information about the error is put into ErrorInfo, and the stream should 349 /// be immediately destroyed; the string will be empty if no error occurred. 350 /// This allows optional flags to control how the file will be opened. 351 /// 352 /// As a special case, if Filename is "-", then the stream will use 353 /// STDOUT_FILENO instead of opening a file. Note that it will still consider 354 /// itself to own the file descriptor. In particular, it will close the 355 /// file descriptor when it is done (this is necessary to detect 356 /// output errors). 357 raw_fd_ostream(const char *Filename, std::string &ErrorInfo, 358 unsigned Flags = 0); 359 360 /// raw_fd_ostream ctor - FD is the file descriptor that this writes to. If 361 /// ShouldClose is true, this closes the file when the stream is destroyed. 362 raw_fd_ostream(int fd, bool shouldClose, bool unbuffered=false); 363 364 ~raw_fd_ostream(); 365 366 /// close - Manually flush the stream and close the file. 367 /// Note that this does not call fsync. 368 void close(); 369 370 /// seek - Flushes the stream and repositions the underlying file descriptor 371 /// position to the offset specified from the beginning of the file. 372 uint64_t seek(uint64_t off); 373 374 /// SetUseAtomicWrite - Set the stream to attempt to use atomic writes for 375 /// individual output routines where possible. 376 /// 377 /// Note that because raw_ostream's are typically buffered, this flag is only 378 /// sensible when used on unbuffered streams which will flush their output 379 /// immediately. 380 void SetUseAtomicWrites(bool Value) { 381 UseAtomicWrites = Value; 382 } 383 384 virtual raw_ostream &changeColor(enum Colors colors, bool bold=false, 385 bool bg=false); 386 virtual raw_ostream &resetColor(); 387 388 virtual raw_ostream &reverseColor(); 389 390 virtual bool is_displayed() const; 391 392 virtual bool has_colors() const; 393 394 /// has_error - Return the value of the flag in this raw_fd_ostream indicating 395 /// whether an output error has been encountered. 396 /// This doesn't implicitly flush any pending output. Also, it doesn't 397 /// guarantee to detect all errors unless the stream has been closed. 398 bool has_error() const { 399 return Error; 400 } 401 402 /// clear_error - Set the flag read by has_error() to false. If the error 403 /// flag is set at the time when this raw_ostream's destructor is called, 404 /// report_fatal_error is called to report the error. Use clear_error() 405 /// after handling the error to avoid this behavior. 406 /// 407 /// "Errors should never pass silently. 408 /// Unless explicitly silenced." 409 /// - from The Zen of Python, by Tim Peters 410 /// 411 void clear_error() { 412 Error = false; 413 } 414}; 415 416/// outs() - This returns a reference to a raw_ostream for standard output. 417/// Use it like: outs() << "foo" << "bar"; 418raw_ostream &outs(); 419 420/// errs() - This returns a reference to a raw_ostream for standard error. 421/// Use it like: errs() << "foo" << "bar"; 422raw_ostream &errs(); 423 424/// nulls() - This returns a reference to a raw_ostream which simply discards 425/// output. 426raw_ostream &nulls(); 427 428//===----------------------------------------------------------------------===// 429// Output Stream Adaptors 430//===----------------------------------------------------------------------===// 431 432/// raw_string_ostream - A raw_ostream that writes to an std::string. This is a 433/// simple adaptor class. This class does not encounter output errors. 434class raw_string_ostream : public raw_ostream { 435 std::string &OS; 436 437 /// write_impl - See raw_ostream::write_impl. 438 virtual void write_impl(const char *Ptr, size_t Size); 439 440 /// current_pos - Return the current position within the stream, not 441 /// counting the bytes currently in the buffer. 442 virtual uint64_t current_pos() const { return OS.size(); } 443public: 444 explicit raw_string_ostream(std::string &O) : OS(O) {} 445 ~raw_string_ostream(); 446 447 /// str - Flushes the stream contents to the target string and returns 448 /// the string's reference. 449 std::string& str() { 450 flush(); 451 return OS; 452 } 453}; 454 455/// raw_svector_ostream - A raw_ostream that writes to an SmallVector or 456/// SmallString. This is a simple adaptor class. This class does not 457/// encounter output errors. 458class raw_svector_ostream : public raw_ostream { 459 SmallVectorImpl<char> &OS; 460 461 /// write_impl - See raw_ostream::write_impl. 462 virtual void write_impl(const char *Ptr, size_t Size); 463 464 /// current_pos - Return the current position within the stream, not 465 /// counting the bytes currently in the buffer. 466 virtual uint64_t current_pos() const; 467public: 468 /// Construct a new raw_svector_ostream. 469 /// 470 /// \arg O - The vector to write to; this should generally have at least 128 471 /// bytes free to avoid any extraneous memory overhead. 472 explicit raw_svector_ostream(SmallVectorImpl<char> &O); 473 ~raw_svector_ostream(); 474 475 /// resync - This is called when the SmallVector we're appending to is changed 476 /// outside of the raw_svector_ostream's control. It is only safe to do this 477 /// if the raw_svector_ostream has previously been flushed. 478 void resync(); 479 480 /// str - Flushes the stream contents to the target vector and return a 481 /// StringRef for the vector contents. 482 StringRef str(); 483}; 484 485/// raw_null_ostream - A raw_ostream that discards all output. 486class raw_null_ostream : public raw_ostream { 487 /// write_impl - See raw_ostream::write_impl. 488 virtual void write_impl(const char *Ptr, size_t size); 489 490 /// current_pos - Return the current position within the stream, not 491 /// counting the bytes currently in the buffer. 492 virtual uint64_t current_pos() const; 493 494public: 495 explicit raw_null_ostream() {} 496 ~raw_null_ostream(); 497}; 498 499} // end llvm namespace 500 501#endif 502