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/Support/DataTypes.h" |
19 | #include <cassert> |
20 | #include <cstddef> |
21 | #include <cstdint> |
22 | #include <cstring> |
23 | #include <optional> |
24 | #include <string> |
25 | #include <string_view> |
26 | #include <system_error> |
27 | #include <type_traits> |
28 | |
29 | namespace llvm { |
30 | |
31 | class Duration; |
32 | class formatv_object_base; |
33 | class format_object_base; |
34 | class FormattedString; |
35 | class FormattedNumber; |
36 | class FormattedBytes; |
37 | template <class T> class [[nodiscard]] Expected; |
38 | |
39 | namespace sys { |
40 | namespace fs { |
41 | enum FileAccess : unsigned; |
42 | enum OpenFlags : unsigned; |
43 | enum CreationDisposition : unsigned; |
44 | class FileLocker; |
45 | } // end namespace fs |
46 | } // end namespace sys |
47 | |
48 | /// This class implements an extremely fast bulk output stream that can *only* |
49 | /// output to a stream. It does not support seeking, reopening, rewinding, line |
50 | /// buffered disciplines etc. It is a simple buffer that outputs |
51 | /// a chunk at a time. |
52 | class raw_ostream { |
53 | public: |
54 | // Class kinds to support LLVM-style RTTI. |
55 | enum class OStreamKind { |
56 | OK_OStream, |
57 | OK_FDStream, |
58 | }; |
59 | |
60 | private: |
61 | OStreamKind Kind; |
62 | |
63 | /// The buffer is handled in such a way that the buffer is |
64 | /// uninitialized, unbuffered, or out of space when OutBufCur >= |
65 | /// OutBufEnd. Thus a single comparison suffices to determine if we |
66 | /// need to take the slow path to write a single character. |
67 | /// |
68 | /// The buffer is in one of three states: |
69 | /// 1. Unbuffered (BufferMode == Unbuffered) |
70 | /// 1. Uninitialized (BufferMode != Unbuffered && OutBufStart == 0). |
71 | /// 2. Buffered (BufferMode != Unbuffered && OutBufStart != 0 && |
72 | /// OutBufEnd - OutBufStart >= 1). |
73 | /// |
74 | /// If buffered, then the raw_ostream owns the buffer if (BufferMode == |
75 | /// InternalBuffer); otherwise the buffer has been set via SetBuffer and is |
76 | /// managed by the subclass. |
77 | /// |
78 | /// If a subclass installs an external buffer using SetBuffer then it can wait |
79 | /// for a \see write_impl() call to handle the data which has been put into |
80 | /// this buffer. |
81 | char *OutBufStart, *OutBufEnd, *OutBufCur; |
82 | bool ColorEnabled = false; |
83 | |
84 | /// Optional stream this stream is tied to. If this stream is written to, the |
85 | /// tied-to stream will be flushed first. |
86 | raw_ostream *TiedStream = nullptr; |
87 | |
88 | enum class BufferKind { |
89 | Unbuffered = 0, |
90 | InternalBuffer, |
91 | ExternalBuffer |
92 | } BufferMode; |
93 | |
94 | public: |
95 | // color order matches ANSI escape sequence, don't change |
96 | enum class Colors { |
97 | BLACK = 0, |
98 | RED, |
99 | GREEN, |
100 | YELLOW, |
101 | BLUE, |
102 | MAGENTA, |
103 | CYAN, |
104 | WHITE, |
105 | BRIGHT_BLACK, |
106 | BRIGHT_RED, |
107 | BRIGHT_GREEN, |
108 | BRIGHT_YELLOW, |
109 | BRIGHT_BLUE, |
110 | BRIGHT_MAGENTA, |
111 | BRIGHT_CYAN, |
112 | BRIGHT_WHITE, |
113 | SAVEDCOLOR, |
114 | RESET, |
115 | }; |
116 | |
117 | static constexpr Colors BLACK = Colors::BLACK; |
118 | static constexpr Colors RED = Colors::RED; |
119 | static constexpr Colors GREEN = Colors::GREEN; |
120 | static constexpr Colors YELLOW = Colors::YELLOW; |
121 | static constexpr Colors BLUE = Colors::BLUE; |
122 | static constexpr Colors MAGENTA = Colors::MAGENTA; |
123 | static constexpr Colors CYAN = Colors::CYAN; |
124 | static constexpr Colors WHITE = Colors::WHITE; |
125 | static constexpr Colors BRIGHT_BLACK = Colors::BRIGHT_BLACK; |
126 | static constexpr Colors BRIGHT_RED = Colors::BRIGHT_RED; |
127 | static constexpr Colors BRIGHT_GREEN = Colors::BRIGHT_GREEN; |
128 | static constexpr Colors BRIGHT_YELLOW = Colors::BRIGHT_YELLOW; |
129 | static constexpr Colors BRIGHT_BLUE = Colors::BRIGHT_BLUE; |
130 | static constexpr Colors BRIGHT_MAGENTA = Colors::BRIGHT_MAGENTA; |
131 | static constexpr Colors BRIGHT_CYAN = Colors::BRIGHT_CYAN; |
132 | static constexpr Colors BRIGHT_WHITE = Colors::BRIGHT_WHITE; |
133 | static constexpr Colors SAVEDCOLOR = Colors::SAVEDCOLOR; |
134 | static constexpr Colors RESET = Colors::RESET; |
135 | |
136 | explicit raw_ostream(bool unbuffered = false, |
137 | OStreamKind K = OStreamKind::OK_OStream) |
138 | : Kind(K), BufferMode(unbuffered ? BufferKind::Unbuffered |
139 | : BufferKind::InternalBuffer) { |
140 | // Start out ready to flush. |
141 | OutBufStart = OutBufEnd = OutBufCur = nullptr; |
142 | } |
143 | |
144 | raw_ostream(const raw_ostream &) = delete; |
145 | void operator=(const raw_ostream &) = delete; |
146 | |
147 | virtual ~raw_ostream(); |
148 | |
149 | /// tell - Return the current offset with the file. |
150 | uint64_t tell() const { return current_pos() + GetNumBytesInBuffer(); } |
151 | |
152 | OStreamKind get_kind() const { return Kind; } |
153 | |
154 | //===--------------------------------------------------------------------===// |
155 | // Configuration Interface |
156 | //===--------------------------------------------------------------------===// |
157 | |
158 | /// If possible, pre-allocate \p ExtraSize bytes for stream data. |
159 | /// i.e. it extends internal buffers to keep additional ExtraSize bytes. |
160 | /// So that the stream could keep at least tell() + ExtraSize bytes |
161 | /// without re-allocations. reserveExtraSpace() does not change |
162 | /// the size/data of the stream. |
163 | virtual void (uint64_t ) {} |
164 | |
165 | /// Set the stream to be buffered, with an automatically determined buffer |
166 | /// size. |
167 | void SetBuffered(); |
168 | |
169 | /// Set the stream to be buffered, using the specified buffer size. |
170 | void SetBufferSize(size_t Size) { |
171 | flush(); |
172 | SetBufferAndMode(BufferStart: new char[Size], Size, Mode: BufferKind::InternalBuffer); |
173 | } |
174 | |
175 | size_t GetBufferSize() const { |
176 | // If we're supposed to be buffered but haven't actually gotten around |
177 | // to allocating the buffer yet, return the value that would be used. |
178 | if (BufferMode != BufferKind::Unbuffered && OutBufStart == nullptr) |
179 | return preferred_buffer_size(); |
180 | |
181 | // Otherwise just return the size of the allocated buffer. |
182 | return OutBufEnd - OutBufStart; |
183 | } |
184 | |
185 | /// Set the stream to be unbuffered. When unbuffered, the stream will flush |
186 | /// after every write. This routine will also flush the buffer immediately |
187 | /// when the stream is being set to unbuffered. |
188 | void SetUnbuffered() { |
189 | flush(); |
190 | SetBufferAndMode(BufferStart: nullptr, Size: 0, Mode: BufferKind::Unbuffered); |
191 | } |
192 | |
193 | size_t GetNumBytesInBuffer() const { |
194 | return OutBufCur - OutBufStart; |
195 | } |
196 | |
197 | //===--------------------------------------------------------------------===// |
198 | // Data Output Interface |
199 | //===--------------------------------------------------------------------===// |
200 | |
201 | void flush() { |
202 | if (OutBufCur != OutBufStart) |
203 | flush_nonempty(); |
204 | } |
205 | |
206 | raw_ostream &operator<<(char C) { |
207 | if (OutBufCur >= OutBufEnd) |
208 | return write(C); |
209 | *OutBufCur++ = C; |
210 | return *this; |
211 | } |
212 | |
213 | raw_ostream &operator<<(unsigned char C) { |
214 | if (OutBufCur >= OutBufEnd) |
215 | return write(C); |
216 | *OutBufCur++ = C; |
217 | return *this; |
218 | } |
219 | |
220 | raw_ostream &operator<<(signed char C) { |
221 | if (OutBufCur >= OutBufEnd) |
222 | return write(C); |
223 | *OutBufCur++ = C; |
224 | return *this; |
225 | } |
226 | |
227 | raw_ostream &operator<<(StringRef Str) { |
228 | // Inline fast path, particularly for strings with a known length. |
229 | size_t Size = Str.size(); |
230 | |
231 | // Make sure we can use the fast path. |
232 | if (Size > (size_t)(OutBufEnd - OutBufCur)) |
233 | return write(Ptr: Str.data(), Size); |
234 | |
235 | if (Size) { |
236 | memcpy(dest: OutBufCur, src: Str.data(), n: Size); |
237 | OutBufCur += Size; |
238 | } |
239 | return *this; |
240 | } |
241 | |
242 | #if defined(__cpp_char8_t) |
243 | // When using `char8_t *` integers or pointers are written to the ostream |
244 | // instead of UTF-8 code as one might expect. This might lead to unexpected |
245 | // behavior, especially as `u8""` literals are of type `char8_t*` instead of |
246 | // type `char_t*` from C++20 onwards. Thus we disallow using them with |
247 | // raw_ostreams. |
248 | // If you have u8"" literals to stream, you can rewrite them as ordinary |
249 | // literals with escape sequences |
250 | // e.g. replace `u8"\u00a0"` by `"\xc2\xa0"` |
251 | // or use `reinterpret_cast`: |
252 | // e.g. replace `u8"\u00a0"` by `reinterpret_cast<const char *>(u8"\u00a0")` |
253 | raw_ostream &operator<<(const char8_t *Str) = delete; |
254 | #endif |
255 | |
256 | raw_ostream &operator<<(const char *Str) { |
257 | // Inline fast path, particularly for constant strings where a sufficiently |
258 | // smart compiler will simplify strlen. |
259 | |
260 | return this->operator<<(Str: StringRef(Str)); |
261 | } |
262 | |
263 | raw_ostream &operator<<(const std::string &Str) { |
264 | // Avoid the fast path, it would only increase code size for a marginal win. |
265 | return write(Ptr: Str.data(), Size: Str.length()); |
266 | } |
267 | |
268 | raw_ostream &operator<<(const std::string_view &Str) { |
269 | return write(Ptr: Str.data(), Size: Str.length()); |
270 | } |
271 | |
272 | raw_ostream &operator<<(const SmallVectorImpl<char> &Str) { |
273 | return write(Ptr: Str.data(), Size: Str.size()); |
274 | } |
275 | |
276 | raw_ostream &operator<<(unsigned long N); |
277 | raw_ostream &operator<<(long N); |
278 | raw_ostream &operator<<(unsigned long long N); |
279 | raw_ostream &operator<<(long long N); |
280 | raw_ostream &operator<<(const void *P); |
281 | |
282 | raw_ostream &operator<<(unsigned int N) { |
283 | return this->operator<<(N: static_cast<unsigned long>(N)); |
284 | } |
285 | |
286 | raw_ostream &operator<<(int N) { |
287 | return this->operator<<(N: static_cast<long>(N)); |
288 | } |
289 | |
290 | raw_ostream &operator<<(double N); |
291 | |
292 | /// Output \p N in hexadecimal, without any prefix or padding. |
293 | raw_ostream &write_hex(unsigned long long N); |
294 | |
295 | // Change the foreground color of text. |
296 | raw_ostream &operator<<(Colors C); |
297 | |
298 | /// Output a formatted UUID with dash separators. |
299 | using uuid_t = uint8_t[16]; |
300 | raw_ostream &write_uuid(const uuid_t UUID); |
301 | |
302 | /// Output \p Str, turning '\\', '\t', '\n', '"', and anything that doesn't |
303 | /// satisfy llvm::isPrint into an escape sequence. |
304 | raw_ostream &write_escaped(StringRef Str, bool UseHexEscapes = false); |
305 | |
306 | raw_ostream &write(unsigned char C); |
307 | raw_ostream &write(const char *Ptr, size_t Size); |
308 | |
309 | // Formatted output, see the format() function in Support/Format.h. |
310 | raw_ostream &operator<<(const format_object_base &Fmt); |
311 | |
312 | // Formatted output, see the leftJustify() function in Support/Format.h. |
313 | raw_ostream &operator<<(const FormattedString &); |
314 | |
315 | // Formatted output, see the formatHex() function in Support/Format.h. |
316 | raw_ostream &operator<<(const FormattedNumber &); |
317 | |
318 | // Formatted output, see the formatv() function in Support/FormatVariadic.h. |
319 | raw_ostream &operator<<(const formatv_object_base &); |
320 | |
321 | // Formatted output, see the format_bytes() function in Support/Format.h. |
322 | raw_ostream &operator<<(const FormattedBytes &); |
323 | |
324 | /// indent - Insert 'NumSpaces' spaces. |
325 | raw_ostream &indent(unsigned NumSpaces); |
326 | |
327 | /// write_zeros - Insert 'NumZeros' nulls. |
328 | raw_ostream &write_zeros(unsigned NumZeros); |
329 | |
330 | /// Changes the foreground color of text that will be output from this point |
331 | /// forward. |
332 | /// @param Color ANSI color to use, the special SAVEDCOLOR can be used to |
333 | /// change only the bold attribute, and keep colors untouched |
334 | /// @param Bold bold/brighter text, default false |
335 | /// @param BG if true change the background, default: change foreground |
336 | /// @returns itself so it can be used within << invocations |
337 | virtual raw_ostream &changeColor(enum Colors Color, bool Bold = false, |
338 | bool BG = false); |
339 | |
340 | /// Resets the colors to terminal defaults. Call this when you are done |
341 | /// outputting colored text, or before program exit. |
342 | virtual raw_ostream &resetColor(); |
343 | |
344 | /// Reverses the foreground and background colors. |
345 | virtual raw_ostream &reverseColor(); |
346 | |
347 | /// This function determines if this stream is connected to a "tty" or |
348 | /// "console" window. That is, the output would be displayed to the user |
349 | /// rather than being put on a pipe or stored in a file. |
350 | virtual bool is_displayed() const { return false; } |
351 | |
352 | /// This function determines if this stream is displayed and supports colors. |
353 | /// The result is unaffected by calls to enable_color(). |
354 | virtual bool has_colors() const { return is_displayed(); } |
355 | |
356 | // Enable or disable colors. Once enable_colors(false) is called, |
357 | // changeColor() has no effect until enable_colors(true) is called. |
358 | virtual void enable_colors(bool enable) { ColorEnabled = enable; } |
359 | |
360 | bool colors_enabled() const { return ColorEnabled; } |
361 | |
362 | /// Tie this stream to the specified stream. Replaces any existing tied-to |
363 | /// stream. Specifying a nullptr unties the stream. |
364 | void tie(raw_ostream *TieTo) { TiedStream = TieTo; } |
365 | |
366 | //===--------------------------------------------------------------------===// |
367 | // Subclass Interface |
368 | //===--------------------------------------------------------------------===// |
369 | |
370 | private: |
371 | /// The is the piece of the class that is implemented by subclasses. This |
372 | /// writes the \p Size bytes starting at |
373 | /// \p Ptr to the underlying stream. |
374 | /// |
375 | /// This function is guaranteed to only be called at a point at which it is |
376 | /// safe for the subclass to install a new buffer via SetBuffer. |
377 | /// |
378 | /// \param Ptr The start of the data to be written. For buffered streams this |
379 | /// is guaranteed to be the start of the buffer. |
380 | /// |
381 | /// \param Size The number of bytes to be written. |
382 | /// |
383 | /// \invariant { Size > 0 } |
384 | virtual void write_impl(const char *Ptr, size_t Size) = 0; |
385 | |
386 | /// Return the current position within the stream, not counting the bytes |
387 | /// currently in the buffer. |
388 | virtual uint64_t current_pos() const = 0; |
389 | |
390 | protected: |
391 | /// Use the provided buffer as the raw_ostream buffer. This is intended for |
392 | /// use only by subclasses which can arrange for the output to go directly |
393 | /// into the desired output buffer, instead of being copied on each flush. |
394 | void SetBuffer(char *BufferStart, size_t Size) { |
395 | SetBufferAndMode(BufferStart, Size, Mode: BufferKind::ExternalBuffer); |
396 | } |
397 | |
398 | /// Return an efficient buffer size for the underlying output mechanism. |
399 | virtual size_t preferred_buffer_size() const; |
400 | |
401 | /// Return the beginning of the current stream buffer, or 0 if the stream is |
402 | /// unbuffered. |
403 | const char *getBufferStart() const { return OutBufStart; } |
404 | |
405 | //===--------------------------------------------------------------------===// |
406 | // Private Interface |
407 | //===--------------------------------------------------------------------===// |
408 | private: |
409 | /// Install the given buffer and mode. |
410 | void SetBufferAndMode(char *BufferStart, size_t Size, BufferKind Mode); |
411 | |
412 | /// Flush the current buffer, which is known to be non-empty. This outputs the |
413 | /// currently buffered data and resets the buffer to empty. |
414 | void flush_nonempty(); |
415 | |
416 | /// Copy data into the buffer. Size must not be greater than the number of |
417 | /// unused bytes in the buffer. |
418 | void copy_to_buffer(const char *Ptr, size_t Size); |
419 | |
420 | /// Compute whether colors should be used and do the necessary work such as |
421 | /// flushing. The result is affected by calls to enable_color(). |
422 | bool prepare_colors(); |
423 | |
424 | /// Flush the tied-to stream (if present) and then write the required data. |
425 | void flush_tied_then_write(const char *Ptr, size_t Size); |
426 | |
427 | virtual void anchor(); |
428 | }; |
429 | |
430 | /// Call the appropriate insertion operator, given an rvalue reference to a |
431 | /// raw_ostream object and return a stream of the same type as the argument. |
432 | template <typename OStream, typename T> |
433 | std::enable_if_t<!std::is_reference_v<OStream> && |
434 | std::is_base_of_v<raw_ostream, OStream>, |
435 | OStream &&> |
436 | operator<<(OStream &&OS, const T &Value) { |
437 | OS << Value; |
438 | return std::move(OS); |
439 | } |
440 | |
441 | /// An abstract base class for streams implementations that also support a |
442 | /// pwrite operation. This is useful for code that can mostly stream out data, |
443 | /// but needs to patch in a header that needs to know the output size. |
444 | class raw_pwrite_stream : public raw_ostream { |
445 | virtual void pwrite_impl(const char *Ptr, size_t Size, uint64_t Offset) = 0; |
446 | void anchor() override; |
447 | |
448 | public: |
449 | explicit raw_pwrite_stream(bool Unbuffered = false, |
450 | OStreamKind K = OStreamKind::OK_OStream) |
451 | : raw_ostream(Unbuffered, K) {} |
452 | void pwrite(const char *Ptr, size_t Size, uint64_t Offset) { |
453 | #ifndef NDEBUG |
454 | uint64_t Pos = tell(); |
455 | // /dev/null always reports a pos of 0, so we cannot perform this check |
456 | // in that case. |
457 | if (Pos) |
458 | assert(Size + Offset <= Pos && "We don't support extending the stream" ); |
459 | #endif |
460 | pwrite_impl(Ptr, Size, Offset); |
461 | } |
462 | }; |
463 | |
464 | //===----------------------------------------------------------------------===// |
465 | // File Output Streams |
466 | //===----------------------------------------------------------------------===// |
467 | |
468 | /// A raw_ostream that writes to a file descriptor. |
469 | /// |
470 | class raw_fd_ostream : public raw_pwrite_stream { |
471 | int FD; |
472 | bool ShouldClose; |
473 | bool SupportsSeeking = false; |
474 | bool IsRegularFile = false; |
475 | mutable std::optional<bool> HasColors; |
476 | |
477 | #ifdef _WIN32 |
478 | /// True if this fd refers to a Windows console device. Mintty and other |
479 | /// terminal emulators are TTYs, but they are not consoles. |
480 | bool IsWindowsConsole = false; |
481 | #endif |
482 | |
483 | std::error_code EC; |
484 | |
485 | uint64_t pos = 0; |
486 | |
487 | /// See raw_ostream::write_impl. |
488 | void write_impl(const char *Ptr, size_t Size) override; |
489 | |
490 | void pwrite_impl(const char *Ptr, size_t Size, uint64_t Offset) override; |
491 | |
492 | /// Return the current position within the stream, not counting the bytes |
493 | /// currently in the buffer. |
494 | uint64_t current_pos() const override { return pos; } |
495 | |
496 | /// Determine an efficient buffer size. |
497 | size_t preferred_buffer_size() const override; |
498 | |
499 | void anchor() override; |
500 | |
501 | protected: |
502 | /// Set the flag indicating that an output error has been encountered. |
503 | void error_detected(std::error_code EC) { this->EC = EC; } |
504 | |
505 | /// Return the file descriptor. |
506 | int get_fd() const { return FD; } |
507 | |
508 | // Update the file position by increasing \p Delta. |
509 | void inc_pos(uint64_t Delta) { pos += Delta; } |
510 | |
511 | public: |
512 | /// Open the specified file for writing. If an error occurs, information |
513 | /// about the error is put into EC, and the stream should be immediately |
514 | /// destroyed; |
515 | /// \p Flags allows optional flags to control how the file will be opened. |
516 | /// |
517 | /// As a special case, if Filename is "-", then the stream will use |
518 | /// STDOUT_FILENO instead of opening a file. This will not close the stdout |
519 | /// descriptor. |
520 | raw_fd_ostream(StringRef Filename, std::error_code &EC); |
521 | raw_fd_ostream(StringRef Filename, std::error_code &EC, |
522 | sys::fs::CreationDisposition Disp); |
523 | raw_fd_ostream(StringRef Filename, std::error_code &EC, |
524 | sys::fs::FileAccess Access); |
525 | raw_fd_ostream(StringRef Filename, std::error_code &EC, |
526 | sys::fs::OpenFlags Flags); |
527 | raw_fd_ostream(StringRef Filename, std::error_code &EC, |
528 | sys::fs::CreationDisposition Disp, sys::fs::FileAccess Access, |
529 | sys::fs::OpenFlags Flags); |
530 | |
531 | /// FD is the file descriptor that this writes to. If ShouldClose is true, |
532 | /// this closes the file when the stream is destroyed. If FD is for stdout or |
533 | /// stderr, it will not be closed. |
534 | raw_fd_ostream(int fd, bool shouldClose, bool unbuffered = false, |
535 | OStreamKind K = OStreamKind::OK_OStream); |
536 | |
537 | ~raw_fd_ostream() override; |
538 | |
539 | /// Manually flush the stream and close the file. Note that this does not call |
540 | /// fsync. |
541 | void close(); |
542 | |
543 | bool supportsSeeking() const { return SupportsSeeking; } |
544 | |
545 | bool isRegularFile() const { return IsRegularFile; } |
546 | |
547 | /// Flushes the stream and repositions the underlying file descriptor position |
548 | /// to the offset specified from the beginning of the file. |
549 | uint64_t seek(uint64_t off); |
550 | |
551 | bool is_displayed() const override; |
552 | |
553 | bool has_colors() const override; |
554 | |
555 | std::error_code error() const { return EC; } |
556 | |
557 | /// Return the value of the flag in this raw_fd_ostream indicating whether an |
558 | /// output error has been encountered. |
559 | /// This doesn't implicitly flush any pending output. Also, it doesn't |
560 | /// guarantee to detect all errors unless the stream has been closed. |
561 | bool has_error() const { return bool(EC); } |
562 | |
563 | /// Set the flag read by has_error() to false. If the error flag is set at the |
564 | /// time when this raw_ostream's destructor is called, report_fatal_error is |
565 | /// called to report the error. Use clear_error() after handling the error to |
566 | /// avoid this behavior. |
567 | /// |
568 | /// "Errors should never pass silently. |
569 | /// Unless explicitly silenced." |
570 | /// - from The Zen of Python, by Tim Peters |
571 | /// |
572 | void clear_error() { EC = std::error_code(); } |
573 | |
574 | /// Locks the underlying file. |
575 | /// |
576 | /// @returns RAII object that releases the lock upon leaving the scope, if the |
577 | /// locking was successful. Otherwise returns corresponding |
578 | /// error code. |
579 | /// |
580 | /// The function blocks the current thread until the lock become available or |
581 | /// error occurs. |
582 | /// |
583 | /// Possible use of this function may be as follows: |
584 | /// |
585 | /// @code{.cpp} |
586 | /// if (auto L = stream.lock()) { |
587 | /// // ... do action that require file to be locked. |
588 | /// } else { |
589 | /// handleAllErrors(std::move(L.takeError()), [&](ErrorInfoBase &EIB) { |
590 | /// // ... handle lock error. |
591 | /// }); |
592 | /// } |
593 | /// @endcode |
594 | [[nodiscard]] Expected<sys::fs::FileLocker> lock(); |
595 | |
596 | /// Tries to lock the underlying file within the specified period. |
597 | /// |
598 | /// @returns RAII object that releases the lock upon leaving the scope, if the |
599 | /// locking was successful. Otherwise returns corresponding |
600 | /// error code. |
601 | /// |
602 | /// It is used as @ref lock. |
603 | [[nodiscard]] Expected<sys::fs::FileLocker> |
604 | tryLockFor(Duration const &Timeout); |
605 | }; |
606 | |
607 | /// This returns a reference to a raw_fd_ostream for standard output. Use it |
608 | /// like: outs() << "foo" << "bar"; |
609 | raw_fd_ostream &outs(); |
610 | |
611 | /// This returns a reference to a raw_ostream for standard error. |
612 | /// Use it like: errs() << "foo" << "bar"; |
613 | /// By default, the stream is tied to stdout to ensure stdout is flushed before |
614 | /// stderr is written, to ensure the error messages are written in their |
615 | /// expected place. |
616 | raw_fd_ostream &errs(); |
617 | |
618 | /// This returns a reference to a raw_ostream which simply discards output. |
619 | raw_ostream &nulls(); |
620 | |
621 | //===----------------------------------------------------------------------===// |
622 | // File Streams |
623 | //===----------------------------------------------------------------------===// |
624 | |
625 | /// A raw_ostream of a file for reading/writing/seeking. |
626 | /// |
627 | class raw_fd_stream : public raw_fd_ostream { |
628 | public: |
629 | /// Open the specified file for reading/writing/seeking. If an error occurs, |
630 | /// information about the error is put into EC, and the stream should be |
631 | /// immediately destroyed. |
632 | raw_fd_stream(StringRef Filename, std::error_code &EC); |
633 | |
634 | raw_fd_stream(int fd, bool shouldClose); |
635 | |
636 | /// This reads the \p Size bytes into a buffer pointed by \p Ptr. |
637 | /// |
638 | /// \param Ptr The start of the buffer to hold data to be read. |
639 | /// |
640 | /// \param Size The number of bytes to be read. |
641 | /// |
642 | /// On success, the number of bytes read is returned, and the file position is |
643 | /// advanced by this number. On error, -1 is returned, use error() to get the |
644 | /// error code. |
645 | ssize_t read(char *Ptr, size_t Size); |
646 | |
647 | /// Check if \p OS is a pointer of type raw_fd_stream*. |
648 | static bool classof(const raw_ostream *OS); |
649 | }; |
650 | |
651 | //===----------------------------------------------------------------------===// |
652 | // Output Stream Adaptors |
653 | //===----------------------------------------------------------------------===// |
654 | |
655 | /// A raw_ostream that writes to an std::string. This is a simple adaptor |
656 | /// class. This class does not encounter output errors. |
657 | /// raw_string_ostream operates without a buffer, delegating all memory |
658 | /// management to the std::string. Thus the std::string is always up-to-date, |
659 | /// may be used directly and there is no need to call flush(). |
660 | class raw_string_ostream : public raw_ostream { |
661 | std::string &OS; |
662 | |
663 | /// See raw_ostream::write_impl. |
664 | void write_impl(const char *Ptr, size_t Size) override; |
665 | |
666 | /// Return the current position within the stream, not counting the bytes |
667 | /// currently in the buffer. |
668 | uint64_t current_pos() const override { return OS.size(); } |
669 | |
670 | public: |
671 | explicit raw_string_ostream(std::string &O) : OS(O) { |
672 | SetUnbuffered(); |
673 | } |
674 | |
675 | /// Returns the string's reference. In most cases it is better to simply use |
676 | /// the underlying std::string directly. |
677 | /// TODO: Consider removing this API. |
678 | std::string &str() { return OS; } |
679 | |
680 | void (uint64_t ) override { |
681 | OS.reserve(res: tell() + ExtraSize); |
682 | } |
683 | }; |
684 | |
685 | /// A raw_ostream that writes to an SmallVector or SmallString. This is a |
686 | /// simple adaptor class. This class does not encounter output errors. |
687 | /// raw_svector_ostream operates without a buffer, delegating all memory |
688 | /// management to the SmallString. Thus the SmallString is always up-to-date, |
689 | /// may be used directly and there is no need to call flush(). |
690 | class raw_svector_ostream : public raw_pwrite_stream { |
691 | SmallVectorImpl<char> &OS; |
692 | |
693 | /// See raw_ostream::write_impl. |
694 | void write_impl(const char *Ptr, size_t Size) override; |
695 | |
696 | void pwrite_impl(const char *Ptr, size_t Size, uint64_t Offset) override; |
697 | |
698 | /// Return the current position within the stream. |
699 | uint64_t current_pos() const override; |
700 | |
701 | public: |
702 | /// Construct a new raw_svector_ostream. |
703 | /// |
704 | /// \param O The vector to write to; this should generally have at least 128 |
705 | /// bytes free to avoid any extraneous memory overhead. |
706 | explicit raw_svector_ostream(SmallVectorImpl<char> &O) : OS(O) { |
707 | SetUnbuffered(); |
708 | } |
709 | |
710 | ~raw_svector_ostream() override = default; |
711 | |
712 | void flush() = delete; |
713 | |
714 | /// Return a StringRef for the vector contents. |
715 | StringRef str() const { return StringRef(OS.data(), OS.size()); } |
716 | |
717 | void (uint64_t ) override { |
718 | OS.reserve(N: tell() + ExtraSize); |
719 | } |
720 | }; |
721 | |
722 | /// A raw_ostream that discards all output. |
723 | class raw_null_ostream : public raw_pwrite_stream { |
724 | /// See raw_ostream::write_impl. |
725 | void write_impl(const char *Ptr, size_t size) override; |
726 | void pwrite_impl(const char *Ptr, size_t Size, uint64_t Offset) override; |
727 | |
728 | /// Return the current position within the stream, not counting the bytes |
729 | /// currently in the buffer. |
730 | uint64_t current_pos() const override; |
731 | |
732 | public: |
733 | explicit raw_null_ostream() = default; |
734 | ~raw_null_ostream() override; |
735 | }; |
736 | |
737 | class buffer_ostream : public raw_svector_ostream { |
738 | raw_ostream &OS; |
739 | SmallVector<char, 0> Buffer; |
740 | |
741 | void anchor() override; |
742 | |
743 | public: |
744 | buffer_ostream(raw_ostream &OS) : raw_svector_ostream(Buffer), OS(OS) {} |
745 | ~buffer_ostream() override { OS << str(); } |
746 | }; |
747 | |
748 | class buffer_unique_ostream : public raw_svector_ostream { |
749 | std::unique_ptr<raw_ostream> OS; |
750 | SmallVector<char, 0> Buffer; |
751 | |
752 | void anchor() override; |
753 | |
754 | public: |
755 | buffer_unique_ostream(std::unique_ptr<raw_ostream> OS) |
756 | : raw_svector_ostream(Buffer), OS(std::move(OS)) { |
757 | // Turn off buffering on OS, which we now own, to avoid allocating a buffer |
758 | // when the destructor writes only to be immediately flushed again. |
759 | this->OS->SetUnbuffered(); |
760 | } |
761 | ~buffer_unique_ostream() override { *OS << str(); } |
762 | }; |
763 | |
764 | class Error; |
765 | |
766 | /// This helper creates an output stream and then passes it to \p Write. |
767 | /// The stream created is based on the specified \p OutputFileName: |
768 | /// llvm::outs for "-", raw_null_ostream for "/dev/null", and raw_fd_ostream |
769 | /// for other names. For raw_fd_ostream instances, the stream writes to |
770 | /// a temporary file. The final output file is atomically replaced with the |
771 | /// temporary file after the \p Write function is finished. |
772 | Error writeToOutput(StringRef OutputFileName, |
773 | std::function<Error(raw_ostream &)> Write); |
774 | |
775 | raw_ostream &operator<<(raw_ostream &OS, std::nullopt_t); |
776 | |
777 | template <typename T, typename = decltype(std::declval<raw_ostream &>() |
778 | << std::declval<const T &>())> |
779 | raw_ostream &operator<<(raw_ostream &OS, const std::optional<T> &O) { |
780 | if (O) |
781 | OS << *O; |
782 | else |
783 | OS << std::nullopt; |
784 | return OS; |
785 | } |
786 | |
787 | } // end namespace llvm |
788 | |
789 | #endif // LLVM_SUPPORT_RAW_OSTREAM_H |
790 | |