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