1 | //===--- raw_ostream.h - Raw output stream ----------------------*- 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 | // This file defines the raw_ostream class. |
10 | // |
11 | //===----------------------------------------------------------------------===// |
12 | |
13 | #ifndef LLVM_SUPPORT_RAW_OSTREAM_H |
14 | #define LLVM_SUPPORT_RAW_OSTREAM_H |
15 | |
16 | #include "llvm/ADT/SmallVector.h" |
17 | #include "llvm/ADT/StringRef.h" |
18 | #include "llvm/ADT/Optional.h" |
19 | #include "llvm/Support/DataTypes.h" |
20 | #include <cassert> |
21 | #include <cstddef> |
22 | #include <cstdint> |
23 | #include <cstring> |
24 | #include <string> |
25 | #if __cplusplus > 201402L |
26 | #include <string_view> |
27 | #endif |
28 | #include <system_error> |
29 | #include <type_traits> |
30 | |
31 | namespace llvm { |
32 | |
33 | class Duration; |
34 | class formatv_object_base; |
35 | class format_object_base; |
36 | class FormattedString; |
37 | class FormattedNumber; |
38 | class FormattedBytes; |
39 | template <class T> class LLVM_NODISCARD Expected; |
40 | |
41 | namespace sys { |
42 | namespace fs { |
43 | enum FileAccess : unsigned; |
44 | enum OpenFlags : unsigned; |
45 | enum CreationDisposition : unsigned; |
46 | class FileLocker; |
47 | } // end namespace fs |
48 | } // end namespace sys |
49 | |
50 | /// This class implements an extremely fast bulk output stream that can *only* |
51 | /// output to a stream. It does not support seeking, reopening, rewinding, line |
52 | /// buffered disciplines etc. It is a simple buffer that outputs |
53 | /// a chunk at a time. |
54 | class raw_ostream { |
55 | public: |
56 | // Class kinds to support LLVM-style RTTI. |
57 | enum class OStreamKind { |
58 | OK_OStream, |
59 | OK_FDStream, |
60 | }; |
61 | |
62 | private: |
63 | OStreamKind Kind; |
64 | |
65 | /// The buffer is handled in such a way that the buffer is |
66 | /// uninitialized, unbuffered, or out of space when OutBufCur >= |
67 | /// OutBufEnd. Thus a single comparison suffices to determine if we |
68 | /// need to take the slow path to write a single character. |
69 | /// |
70 | /// The buffer is in one of three states: |
71 | /// 1. Unbuffered (BufferMode == Unbuffered) |
72 | /// 1. Uninitialized (BufferMode != Unbuffered && OutBufStart == 0). |
73 | /// 2. Buffered (BufferMode != Unbuffered && OutBufStart != 0 && |
74 | /// OutBufEnd - OutBufStart >= 1). |
75 | /// |
76 | /// If buffered, then the raw_ostream owns the buffer if (BufferMode == |
77 | /// InternalBuffer); otherwise the buffer has been set via SetBuffer and is |
78 | /// managed by the subclass. |
79 | /// |
80 | /// If a subclass installs an external buffer using SetBuffer then it can wait |
81 | /// for a \see write_impl() call to handle the data which has been put into |
82 | /// this buffer. |
83 | char *OutBufStart, *OutBufEnd, *OutBufCur; |
84 | bool ColorEnabled = false; |
85 | |
86 | /// Optional stream this stream is tied to. If this stream is written to, the |
87 | /// tied-to stream will be flushed first. |
88 | raw_ostream *TiedStream = nullptr; |
89 | |
90 | enum class BufferKind { |
91 | Unbuffered = 0, |
92 | InternalBuffer, |
93 | ExternalBuffer |
94 | } BufferMode; |
95 | |
96 | public: |
97 | // color order matches ANSI escape sequence, don't change |
98 | enum class Colors { |
99 | BLACK = 0, |
100 | RED, |
101 | GREEN, |
102 | YELLOW, |
103 | BLUE, |
104 | MAGENTA, |
105 | CYAN, |
106 | WHITE, |
107 | SAVEDCOLOR, |
108 | RESET, |
109 | }; |
110 | |
111 | static constexpr Colors BLACK = Colors::BLACK; |
112 | static constexpr Colors RED = Colors::RED; |
113 | static constexpr Colors GREEN = Colors::GREEN; |
114 | static constexpr Colors YELLOW = Colors::YELLOW; |
115 | static constexpr Colors BLUE = Colors::BLUE; |
116 | static constexpr Colors MAGENTA = Colors::MAGENTA; |
117 | static constexpr Colors CYAN = Colors::CYAN; |
118 | static constexpr Colors WHITE = Colors::WHITE; |
119 | static constexpr Colors SAVEDCOLOR = Colors::SAVEDCOLOR; |
120 | static constexpr Colors RESET = Colors::RESET; |
121 | |
122 | explicit raw_ostream(bool unbuffered = false, |
123 | OStreamKind K = OStreamKind::OK_OStream) |
124 | : Kind(K), BufferMode(unbuffered ? BufferKind::Unbuffered |
125 | : BufferKind::InternalBuffer) { |
126 | // Start out ready to flush. |
127 | OutBufStart = OutBufEnd = OutBufCur = nullptr; |
128 | } |
129 | |
130 | raw_ostream(const raw_ostream &) = delete; |
131 | void operator=(const raw_ostream &) = delete; |
132 | |
133 | virtual ~raw_ostream(); |
134 | |
135 | /// tell - Return the current offset with the file. |
136 | uint64_t tell() const { return current_pos() + GetNumBytesInBuffer(); } |
137 | |
138 | OStreamKind get_kind() const { return Kind; } |
139 | |
140 | //===--------------------------------------------------------------------===// |
141 | // Configuration Interface |
142 | //===--------------------------------------------------------------------===// |
143 | |
144 | /// If possible, pre-allocate \p ExtraSize bytes for stream data. |
145 | /// i.e. it extends internal buffers to keep additional ExtraSize bytes. |
146 | /// So that the stream could keep at least tell() + ExtraSize bytes |
147 | /// without re-allocations. reserveExtraSpace() does not change |
148 | /// the size/data of the stream. |
149 | virtual void (uint64_t ) {} |
150 | |
151 | /// Set the stream to be buffered, with an automatically determined buffer |
152 | /// size. |
153 | void SetBuffered(); |
154 | |
155 | /// Set the stream to be buffered, using the specified buffer size. |
156 | void SetBufferSize(size_t Size) { |
157 | flush(); |
158 | SetBufferAndMode(new char[Size], Size, BufferKind::InternalBuffer); |
159 | } |
160 | |
161 | size_t GetBufferSize() const { |
162 | // If we're supposed to be buffered but haven't actually gotten around |
163 | // to allocating the buffer yet, return the value that would be used. |
164 | if (BufferMode != BufferKind::Unbuffered && OutBufStart == nullptr) |
165 | return preferred_buffer_size(); |
166 | |
167 | // Otherwise just return the size of the allocated buffer. |
168 | return OutBufEnd - OutBufStart; |
169 | } |
170 | |
171 | /// Set the stream to be unbuffered. When unbuffered, the stream will flush |
172 | /// after every write. This routine will also flush the buffer immediately |
173 | /// when the stream is being set to unbuffered. |
174 | void SetUnbuffered() { |
175 | flush(); |
176 | SetBufferAndMode(nullptr, 0, BufferKind::Unbuffered); |
177 | } |
178 | |
179 | size_t GetNumBytesInBuffer() const { |
180 | return OutBufCur - OutBufStart; |
181 | } |
182 | |
183 | //===--------------------------------------------------------------------===// |
184 | // Data Output Interface |
185 | //===--------------------------------------------------------------------===// |
186 | |
187 | void flush() { |
188 | if (OutBufCur != OutBufStart) |
189 | flush_nonempty(); |
190 | } |
191 | |
192 | raw_ostream &operator<<(char C) { |
193 | if (OutBufCur >= OutBufEnd) |
194 | return write(C); |
195 | *OutBufCur++ = C; |
196 | return *this; |
197 | } |
198 | |
199 | raw_ostream &operator<<(unsigned char C) { |
200 | if (OutBufCur >= OutBufEnd) |
201 | return write(C); |
202 | *OutBufCur++ = C; |
203 | return *this; |
204 | } |
205 | |
206 | raw_ostream &operator<<(signed char C) { |
207 | if (OutBufCur >= OutBufEnd) |
208 | return write(C); |
209 | *OutBufCur++ = C; |
210 | return *this; |
211 | } |
212 | |
213 | raw_ostream &operator<<(StringRef Str) { |
214 | // Inline fast path, particularly for strings with a known length. |
215 | size_t Size = Str.size(); |
216 | |
217 | // Make sure we can use the fast path. |
218 | if (Size > (size_t)(OutBufEnd - OutBufCur)) |
219 | return write(Str.data(), Size); |
220 | |
221 | if (Size) { |
222 | memcpy(OutBufCur, Str.data(), Size); |
223 | OutBufCur += Size; |
224 | } |
225 | return *this; |
226 | } |
227 | |
228 | raw_ostream &operator<<(const char *Str) { |
229 | // Inline fast path, particularly for constant strings where a sufficiently |
230 | // smart compiler will simplify strlen. |
231 | |
232 | return this->operator<<(StringRef(Str)); |
233 | } |
234 | |
235 | raw_ostream &operator<<(const std::string &Str) { |
236 | // Avoid the fast path, it would only increase code size for a marginal win. |
237 | return write(Str.data(), Str.length()); |
238 | } |
239 | |
240 | #if __cplusplus > 201402L |
241 | raw_ostream &operator<<(const std::string_view &Str) { |
242 | return write(Str.data(), Str.length()); |
243 | } |
244 | #endif |
245 | |
246 | raw_ostream &operator<<(const SmallVectorImpl<char> &Str) { |
247 | return write(Str.data(), Str.size()); |
248 | } |
249 | |
250 | raw_ostream &operator<<(unsigned long N); |
251 | raw_ostream &operator<<(long N); |
252 | raw_ostream &operator<<(unsigned long long N); |
253 | raw_ostream &operator<<(long long N); |
254 | raw_ostream &operator<<(const void *P); |
255 | |
256 | raw_ostream &operator<<(unsigned int N) { |
257 | return this->operator<<(static_cast<unsigned long>(N)); |
258 | } |
259 | |
260 | raw_ostream &operator<<(int N) { |
261 | return this->operator<<(static_cast<long>(N)); |
262 | } |
263 | |
264 | raw_ostream &operator<<(double N); |
265 | |
266 | /// Output \p N in hexadecimal, without any prefix or padding. |
267 | raw_ostream &write_hex(unsigned long long N); |
268 | |
269 | // Change the foreground color of text. |
270 | raw_ostream &operator<<(Colors C); |
271 | |
272 | /// Output a formatted UUID with dash separators. |
273 | using uuid_t = uint8_t[16]; |
274 | raw_ostream &write_uuid(const uuid_t UUID); |
275 | |
276 | /// Output \p Str, turning '\\', '\t', '\n', '"', and anything that doesn't |
277 | /// satisfy llvm::isPrint into an escape sequence. |
278 | raw_ostream &write_escaped(StringRef Str, bool UseHexEscapes = false); |
279 | |
280 | raw_ostream &write(unsigned char C); |
281 | raw_ostream &write(const char *Ptr, size_t Size); |
282 | |
283 | // Formatted output, see the format() function in Support/Format.h. |
284 | raw_ostream &operator<<(const format_object_base &Fmt); |
285 | |
286 | // Formatted output, see the leftJustify() function in Support/Format.h. |
287 | raw_ostream &operator<<(const FormattedString &); |
288 | |
289 | // Formatted output, see the formatHex() function in Support/Format.h. |
290 | raw_ostream &operator<<(const FormattedNumber &); |
291 | |
292 | // Formatted output, see the formatv() function in Support/FormatVariadic.h. |
293 | raw_ostream &operator<<(const formatv_object_base &); |
294 | |
295 | // Formatted output, see the format_bytes() function in Support/Format.h. |
296 | raw_ostream &operator<<(const FormattedBytes &); |
297 | |
298 | /// indent - Insert 'NumSpaces' spaces. |
299 | raw_ostream &indent(unsigned NumSpaces); |
300 | |
301 | /// write_zeros - Insert 'NumZeros' nulls. |
302 | raw_ostream &write_zeros(unsigned NumZeros); |
303 | |
304 | /// Changes the foreground color of text that will be output from this point |
305 | /// forward. |
306 | /// @param Color ANSI color to use, the special SAVEDCOLOR can be used to |
307 | /// change only the bold attribute, and keep colors untouched |
308 | /// @param Bold bold/brighter text, default false |
309 | /// @param BG if true change the background, default: change foreground |
310 | /// @returns itself so it can be used within << invocations |
311 | virtual raw_ostream &changeColor(enum Colors Color, bool Bold = false, |
312 | bool BG = false); |
313 | |
314 | /// Resets the colors to terminal defaults. Call this when you are done |
315 | /// outputting colored text, or before program exit. |
316 | virtual raw_ostream &resetColor(); |
317 | |
318 | /// Reverses the foreground and background colors. |
319 | virtual raw_ostream &reverseColor(); |
320 | |
321 | /// This function determines if this stream is connected to a "tty" or |
322 | /// "console" window. That is, the output would be displayed to the user |
323 | /// rather than being put on a pipe or stored in a file. |
324 | virtual bool is_displayed() const { return false; } |
325 | |
326 | /// This function determines if this stream is displayed and supports colors. |
327 | /// The result is unaffected by calls to enable_color(). |
328 | virtual bool has_colors() const { return is_displayed(); } |
329 | |
330 | // Enable or disable colors. Once enable_colors(false) is called, |
331 | // changeColor() has no effect until enable_colors(true) is called. |
332 | virtual void enable_colors(bool enable) { ColorEnabled = enable; } |
333 | |
334 | bool colors_enabled() const { return ColorEnabled; } |
335 | |
336 | /// Tie this stream to the specified stream. Replaces any existing tied-to |
337 | /// stream. Specifying a nullptr unties the stream. |
338 | void tie(raw_ostream *TieTo) { TiedStream = TieTo; } |
339 | |
340 | //===--------------------------------------------------------------------===// |
341 | // Subclass Interface |
342 | //===--------------------------------------------------------------------===// |
343 | |
344 | private: |
345 | /// The is the piece of the class that is implemented by subclasses. This |
346 | /// writes the \p Size bytes starting at |
347 | /// \p Ptr to the underlying stream. |
348 | /// |
349 | /// This function is guaranteed to only be called at a point at which it is |
350 | /// safe for the subclass to install a new buffer via SetBuffer. |
351 | /// |
352 | /// \param Ptr The start of the data to be written. For buffered streams this |
353 | /// is guaranteed to be the start of the buffer. |
354 | /// |
355 | /// \param Size The number of bytes to be written. |
356 | /// |
357 | /// \invariant { Size > 0 } |
358 | virtual void write_impl(const char *Ptr, size_t Size) = 0; |
359 | |
360 | /// Return the current position within the stream, not counting the bytes |
361 | /// currently in the buffer. |
362 | virtual uint64_t current_pos() const = 0; |
363 | |
364 | protected: |
365 | /// Use the provided buffer as the raw_ostream buffer. This is intended for |
366 | /// use only by subclasses which can arrange for the output to go directly |
367 | /// into the desired output buffer, instead of being copied on each flush. |
368 | void SetBuffer(char *BufferStart, size_t Size) { |
369 | SetBufferAndMode(BufferStart, Size, BufferKind::ExternalBuffer); |
370 | } |
371 | |
372 | /// Return an efficient buffer size for the underlying output mechanism. |
373 | virtual size_t preferred_buffer_size() const; |
374 | |
375 | /// Return the beginning of the current stream buffer, or 0 if the stream is |
376 | /// unbuffered. |
377 | const char *getBufferStart() const { return OutBufStart; } |
378 | |
379 | //===--------------------------------------------------------------------===// |
380 | // Private Interface |
381 | //===--------------------------------------------------------------------===// |
382 | private: |
383 | /// Install the given buffer and mode. |
384 | void SetBufferAndMode(char *BufferStart, size_t Size, BufferKind Mode); |
385 | |
386 | /// Flush the current buffer, which is known to be non-empty. This outputs the |
387 | /// currently buffered data and resets the buffer to empty. |
388 | void flush_nonempty(); |
389 | |
390 | /// Copy data into the buffer. Size must not be greater than the number of |
391 | /// unused bytes in the buffer. |
392 | void copy_to_buffer(const char *Ptr, size_t Size); |
393 | |
394 | /// Compute whether colors should be used and do the necessary work such as |
395 | /// flushing. The result is affected by calls to enable_color(). |
396 | bool prepare_colors(); |
397 | |
398 | /// Flush the tied-to stream (if present) and then write the required data. |
399 | void flush_tied_then_write(const char *Ptr, size_t Size); |
400 | |
401 | virtual void anchor(); |
402 | }; |
403 | |
404 | /// Call the appropriate insertion operator, given an rvalue reference to a |
405 | /// raw_ostream object and return a stream of the same type as the argument. |
406 | template <typename OStream, typename T> |
407 | std::enable_if_t<!std::is_reference<OStream>::value && |
408 | std::is_base_of<raw_ostream, OStream>::value, |
409 | OStream &&> |
410 | operator<<(OStream &&OS, const T &Value) { |
411 | OS << Value; |
412 | return std::move(OS); |
413 | } |
414 | |
415 | /// An abstract base class for streams implementations that also support a |
416 | /// pwrite operation. This is useful for code that can mostly stream out data, |
417 | /// but needs to patch in a header that needs to know the output size. |
418 | class raw_pwrite_stream : public raw_ostream { |
419 | virtual void pwrite_impl(const char *Ptr, size_t Size, uint64_t Offset) = 0; |
420 | void anchor() override; |
421 | |
422 | public: |
423 | explicit raw_pwrite_stream(bool Unbuffered = false, |
424 | OStreamKind K = OStreamKind::OK_OStream) |
425 | : raw_ostream(Unbuffered, K) {} |
426 | void pwrite(const char *Ptr, size_t Size, uint64_t Offset) { |
427 | #ifndef NDEBUG |
428 | uint64_t Pos = tell(); |
429 | // /dev/null always reports a pos of 0, so we cannot perform this check |
430 | // in that case. |
431 | if (Pos) |
432 | assert(Size + Offset <= Pos && "We don't support extending the stream" ); |
433 | #endif |
434 | pwrite_impl(Ptr, Size, Offset); |
435 | } |
436 | }; |
437 | |
438 | //===----------------------------------------------------------------------===// |
439 | // File Output Streams |
440 | //===----------------------------------------------------------------------===// |
441 | |
442 | /// A raw_ostream that writes to a file descriptor. |
443 | /// |
444 | class raw_fd_ostream : public raw_pwrite_stream { |
445 | int FD; |
446 | bool ShouldClose; |
447 | bool SupportsSeeking = false; |
448 | bool IsRegularFile = false; |
449 | mutable Optional<bool> HasColors; |
450 | |
451 | #ifdef _WIN32 |
452 | /// True if this fd refers to a Windows console device. Mintty and other |
453 | /// terminal emulators are TTYs, but they are not consoles. |
454 | bool IsWindowsConsole = false; |
455 | #endif |
456 | |
457 | std::error_code EC; |
458 | |
459 | uint64_t pos = 0; |
460 | |
461 | /// See raw_ostream::write_impl. |
462 | void write_impl(const char *Ptr, size_t Size) override; |
463 | |
464 | void pwrite_impl(const char *Ptr, size_t Size, uint64_t Offset) override; |
465 | |
466 | /// Return the current position within the stream, not counting the bytes |
467 | /// currently in the buffer. |
468 | uint64_t current_pos() const override { return pos; } |
469 | |
470 | /// Determine an efficient buffer size. |
471 | size_t preferred_buffer_size() const override; |
472 | |
473 | void anchor() override; |
474 | |
475 | protected: |
476 | /// Set the flag indicating that an output error has been encountered. |
477 | void error_detected(std::error_code EC) { this->EC = EC; } |
478 | |
479 | /// Return the file descriptor. |
480 | int get_fd() const { return FD; } |
481 | |
482 | // Update the file position by increasing \p Delta. |
483 | void inc_pos(uint64_t Delta) { pos += Delta; } |
484 | |
485 | public: |
486 | /// Open the specified file for writing. If an error occurs, information |
487 | /// about the error is put into EC, and the stream should be immediately |
488 | /// destroyed; |
489 | /// \p Flags allows optional flags to control how the file will be opened. |
490 | /// |
491 | /// As a special case, if Filename is "-", then the stream will use |
492 | /// STDOUT_FILENO instead of opening a file. This will not close the stdout |
493 | /// descriptor. |
494 | raw_fd_ostream(StringRef Filename, std::error_code &EC); |
495 | raw_fd_ostream(StringRef Filename, std::error_code &EC, |
496 | sys::fs::CreationDisposition Disp); |
497 | raw_fd_ostream(StringRef Filename, std::error_code &EC, |
498 | sys::fs::FileAccess Access); |
499 | raw_fd_ostream(StringRef Filename, std::error_code &EC, |
500 | sys::fs::OpenFlags Flags); |
501 | raw_fd_ostream(StringRef Filename, std::error_code &EC, |
502 | sys::fs::CreationDisposition Disp, sys::fs::FileAccess Access, |
503 | sys::fs::OpenFlags Flags); |
504 | |
505 | /// FD is the file descriptor that this writes to. If ShouldClose is true, |
506 | /// this closes the file when the stream is destroyed. If FD is for stdout or |
507 | /// stderr, it will not be closed. |
508 | raw_fd_ostream(int fd, bool shouldClose, bool unbuffered = false, |
509 | OStreamKind K = OStreamKind::OK_OStream); |
510 | |
511 | ~raw_fd_ostream() override; |
512 | |
513 | /// Manually flush the stream and close the file. Note that this does not call |
514 | /// fsync. |
515 | void close(); |
516 | |
517 | bool supportsSeeking() const { return SupportsSeeking; } |
518 | |
519 | bool isRegularFile() const { return IsRegularFile; } |
520 | |
521 | /// Flushes the stream and repositions the underlying file descriptor position |
522 | /// to the offset specified from the beginning of the file. |
523 | uint64_t seek(uint64_t off); |
524 | |
525 | bool is_displayed() const override; |
526 | |
527 | bool has_colors() const override; |
528 | |
529 | std::error_code error() const { return EC; } |
530 | |
531 | /// Return the value of the flag in this raw_fd_ostream indicating whether an |
532 | /// output error has been encountered. |
533 | /// This doesn't implicitly flush any pending output. Also, it doesn't |
534 | /// guarantee to detect all errors unless the stream has been closed. |
535 | bool has_error() const { return bool(EC); } |
536 | |
537 | /// Set the flag read by has_error() to false. If the error flag is set at the |
538 | /// time when this raw_ostream's destructor is called, report_fatal_error is |
539 | /// called to report the error. Use clear_error() after handling the error to |
540 | /// avoid this behavior. |
541 | /// |
542 | /// "Errors should never pass silently. |
543 | /// Unless explicitly silenced." |
544 | /// - from The Zen of Python, by Tim Peters |
545 | /// |
546 | void clear_error() { EC = std::error_code(); } |
547 | |
548 | /// Locks the underlying file. |
549 | /// |
550 | /// @returns RAII object that releases the lock upon leaving the scope, if the |
551 | /// locking was successful. Otherwise returns corresponding |
552 | /// error code. |
553 | /// |
554 | /// The function blocks the current thread until the lock become available or |
555 | /// error occurs. |
556 | /// |
557 | /// Possible use of this function may be as follows: |
558 | /// |
559 | /// @code{.cpp} |
560 | /// if (auto L = stream.lock()) { |
561 | /// // ... do action that require file to be locked. |
562 | /// } else { |
563 | /// handleAllErrors(std::move(L.takeError()), [&](ErrorInfoBase &EIB) { |
564 | /// // ... handle lock error. |
565 | /// }); |
566 | /// } |
567 | /// @endcode |
568 | LLVM_NODISCARD Expected<sys::fs::FileLocker> lock(); |
569 | |
570 | /// Tries to lock the underlying file within the specified period. |
571 | /// |
572 | /// @returns RAII object that releases the lock upon leaving the scope, if the |
573 | /// locking was successful. Otherwise returns corresponding |
574 | /// error code. |
575 | /// |
576 | /// It is used as @ref lock. |
577 | LLVM_NODISCARD |
578 | Expected<sys::fs::FileLocker> tryLockFor(Duration const& Timeout); |
579 | }; |
580 | |
581 | /// This returns a reference to a raw_fd_ostream for standard output. Use it |
582 | /// like: outs() << "foo" << "bar"; |
583 | raw_fd_ostream &outs(); |
584 | |
585 | /// This returns a reference to a raw_ostream for standard error. |
586 | /// Use it like: errs() << "foo" << "bar"; |
587 | /// By default, the stream is tied to stdout to ensure stdout is flushed before |
588 | /// stderr is written, to ensure the error messages are written in their |
589 | /// expected place. |
590 | raw_fd_ostream &errs(); |
591 | |
592 | /// This returns a reference to a raw_ostream which simply discards output. |
593 | raw_ostream &nulls(); |
594 | |
595 | //===----------------------------------------------------------------------===// |
596 | // File Streams |
597 | //===----------------------------------------------------------------------===// |
598 | |
599 | /// A raw_ostream of a file for reading/writing/seeking. |
600 | /// |
601 | class raw_fd_stream : public raw_fd_ostream { |
602 | public: |
603 | /// Open the specified file for reading/writing/seeking. If an error occurs, |
604 | /// information about the error is put into EC, and the stream should be |
605 | /// immediately destroyed. |
606 | raw_fd_stream(StringRef Filename, std::error_code &EC); |
607 | |
608 | /// This reads the \p Size bytes into a buffer pointed by \p Ptr. |
609 | /// |
610 | /// \param Ptr The start of the buffer to hold data to be read. |
611 | /// |
612 | /// \param Size The number of bytes to be read. |
613 | /// |
614 | /// On success, the number of bytes read is returned, and the file position is |
615 | /// advanced by this number. On error, -1 is returned, use error() to get the |
616 | /// error code. |
617 | ssize_t read(char *Ptr, size_t Size); |
618 | |
619 | /// Check if \p OS is a pointer of type raw_fd_stream*. |
620 | static bool classof(const raw_ostream *OS); |
621 | }; |
622 | |
623 | //===----------------------------------------------------------------------===// |
624 | // Output Stream Adaptors |
625 | //===----------------------------------------------------------------------===// |
626 | |
627 | /// A raw_ostream that writes to an std::string. This is a simple adaptor |
628 | /// class. This class does not encounter output errors. |
629 | /// raw_string_ostream operates without a buffer, delegating all memory |
630 | /// management to the std::string. Thus the std::string is always up-to-date, |
631 | /// may be used directly and there is no need to call flush(). |
632 | class raw_string_ostream : public raw_ostream { |
633 | std::string &OS; |
634 | |
635 | /// See raw_ostream::write_impl. |
636 | void write_impl(const char *Ptr, size_t Size) override; |
637 | |
638 | /// Return the current position within the stream, not counting the bytes |
639 | /// currently in the buffer. |
640 | uint64_t current_pos() const override { return OS.size(); } |
641 | |
642 | public: |
643 | explicit raw_string_ostream(std::string &O) : OS(O) { |
644 | SetUnbuffered(); |
645 | } |
646 | |
647 | /// Returns the string's reference. In most cases it is better to simply use |
648 | /// the underlying std::string directly. |
649 | /// TODO: Consider removing this API. |
650 | std::string &str() { return OS; } |
651 | |
652 | void (uint64_t ) override { |
653 | OS.reserve(tell() + ExtraSize); |
654 | } |
655 | }; |
656 | |
657 | /// A raw_ostream that writes to an SmallVector or SmallString. This is a |
658 | /// simple adaptor class. This class does not encounter output errors. |
659 | /// raw_svector_ostream operates without a buffer, delegating all memory |
660 | /// management to the SmallString. Thus the SmallString is always up-to-date, |
661 | /// may be used directly and there is no need to call flush(). |
662 | class raw_svector_ostream : public raw_pwrite_stream { |
663 | SmallVectorImpl<char> &OS; |
664 | |
665 | /// See raw_ostream::write_impl. |
666 | void write_impl(const char *Ptr, size_t Size) override; |
667 | |
668 | void pwrite_impl(const char *Ptr, size_t Size, uint64_t Offset) override; |
669 | |
670 | /// Return the current position within the stream. |
671 | uint64_t current_pos() const override; |
672 | |
673 | public: |
674 | /// Construct a new raw_svector_ostream. |
675 | /// |
676 | /// \param O The vector to write to; this should generally have at least 128 |
677 | /// bytes free to avoid any extraneous memory overhead. |
678 | explicit raw_svector_ostream(SmallVectorImpl<char> &O) : OS(O) { |
679 | SetUnbuffered(); |
680 | } |
681 | |
682 | ~raw_svector_ostream() override = default; |
683 | |
684 | void flush() = delete; |
685 | |
686 | /// Return a StringRef for the vector contents. |
687 | StringRef str() const { return StringRef(OS.data(), OS.size()); } |
688 | |
689 | void (uint64_t ) override { |
690 | OS.reserve(tell() + ExtraSize); |
691 | } |
692 | }; |
693 | |
694 | /// A raw_ostream that discards all output. |
695 | class raw_null_ostream : public raw_pwrite_stream { |
696 | /// See raw_ostream::write_impl. |
697 | void write_impl(const char *Ptr, size_t size) override; |
698 | void pwrite_impl(const char *Ptr, size_t Size, uint64_t Offset) override; |
699 | |
700 | /// Return the current position within the stream, not counting the bytes |
701 | /// currently in the buffer. |
702 | uint64_t current_pos() const override; |
703 | |
704 | public: |
705 | explicit raw_null_ostream() = default; |
706 | ~raw_null_ostream() override; |
707 | }; |
708 | |
709 | class buffer_ostream : public raw_svector_ostream { |
710 | raw_ostream &OS; |
711 | SmallVector<char, 0> Buffer; |
712 | |
713 | virtual void anchor() override; |
714 | |
715 | public: |
716 | buffer_ostream(raw_ostream &OS) : raw_svector_ostream(Buffer), OS(OS) {} |
717 | ~buffer_ostream() override { OS << str(); } |
718 | }; |
719 | |
720 | class buffer_unique_ostream : public raw_svector_ostream { |
721 | std::unique_ptr<raw_ostream> OS; |
722 | SmallVector<char, 0> Buffer; |
723 | |
724 | virtual void anchor() override; |
725 | |
726 | public: |
727 | buffer_unique_ostream(std::unique_ptr<raw_ostream> OS) |
728 | : raw_svector_ostream(Buffer), OS(std::move(OS)) { |
729 | // Turn off buffering on OS, which we now own, to avoid allocating a buffer |
730 | // when the destructor writes only to be immediately flushed again. |
731 | this->OS->SetUnbuffered(); |
732 | } |
733 | ~buffer_unique_ostream() override { *OS << str(); } |
734 | }; |
735 | |
736 | class Error; |
737 | |
738 | /// This helper creates an output stream and then passes it to \p Write. |
739 | /// The stream created is based on the specified \p OutputFileName: |
740 | /// llvm::outs for "-", raw_null_ostream for "/dev/null", and raw_fd_ostream |
741 | /// for other names. For raw_fd_ostream instances, the stream writes to |
742 | /// a temporary file. The final output file is atomically replaced with the |
743 | /// temporary file after the \p Write function is finished. |
744 | Error writeToOutput(StringRef OutputFileName, |
745 | std::function<Error(raw_ostream &)> Write); |
746 | |
747 | } // end namespace llvm |
748 | |
749 | #endif // LLVM_SUPPORT_RAW_OSTREAM_H |
750 | |