1//===-- llvm/Support/FormattedStream.h - Formatted streams ------*- 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 contains raw_ostream implementations for streams to do
10// things like pretty-print comments.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_SUPPORT_FORMATTEDSTREAM_H
15#define LLVM_SUPPORT_FORMATTEDSTREAM_H
16
17#include "llvm/Support/raw_ostream.h"
18#include <utility>
19
20namespace llvm {
21
22/// formatted_raw_ostream - A raw_ostream that wraps another one and keeps track
23/// of line and column position, allowing padding out to specific column
24/// boundaries and querying the number of lines written to the stream.
25///
26class formatted_raw_ostream : public raw_ostream {
27  /// TheStream - The real stream we output to. We set it to be
28  /// unbuffered, since we're already doing our own buffering.
29  ///
30  raw_ostream *TheStream;
31
32  /// Position - The current output column and line of the data that's
33  /// been flushed and the portion of the buffer that's been
34  /// scanned.  The line and column scheme is zero-based.
35  ///
36  std::pair<unsigned, unsigned> Position;
37
38  /// Scanned - This points to one past the last character in the
39  /// buffer we've scanned.
40  ///
41  const char *Scanned;
42
43  void write_impl(const char *Ptr, size_t Size) override;
44
45  /// current_pos - Return the current position within the stream,
46  /// not counting the bytes currently in the buffer.
47  uint64_t current_pos() const override {
48    // Our current position in the stream is all the contents which have been
49    // written to the underlying stream (*not* the current position of the
50    // underlying stream).
51    return TheStream->tell();
52  }
53
54  /// ComputePosition - Examine the given output buffer and figure out the new
55  /// position after output.
56  ///
57  void ComputePosition(const char *Ptr, size_t size);
58
59  void setStream(raw_ostream &Stream) {
60    releaseStream();
61
62    TheStream = &Stream;
63
64    // This formatted_raw_ostream inherits from raw_ostream, so it'll do its
65    // own buffering, and it doesn't need or want TheStream to do another
66    // layer of buffering underneath. Resize the buffer to what TheStream
67    // had been using, and tell TheStream not to do its own buffering.
68    if (size_t BufferSize = TheStream->GetBufferSize())
69      SetBufferSize(BufferSize);
70    else
71      SetUnbuffered();
72    TheStream->SetUnbuffered();
73
74    Scanned = nullptr;
75  }
76
77public:
78  /// formatted_raw_ostream - Open the specified file for
79  /// writing. If an error occurs, information about the error is
80  /// put into ErrorInfo, and the stream should be immediately
81  /// destroyed; the string will be empty if no error occurred.
82  ///
83  /// As a side effect, the given Stream is set to be Unbuffered.
84  /// This is because formatted_raw_ostream does its own buffering,
85  /// so it doesn't want another layer of buffering to be happening
86  /// underneath it.
87  ///
88  formatted_raw_ostream(raw_ostream &Stream)
89      : TheStream(nullptr), Position(0, 0) {
90    setStream(Stream);
91  }
92  explicit formatted_raw_ostream() : TheStream(nullptr), Position(0, 0) {
93    Scanned = nullptr;
94  }
95
96  ~formatted_raw_ostream() override {
97    flush();
98    releaseStream();
99  }
100
101  /// PadToColumn - Align the output to some column number.  If the current
102  /// column is already equal to or more than NewCol, PadToColumn inserts one
103  /// space.
104  ///
105  /// \param NewCol - The column to move to.
106  formatted_raw_ostream &PadToColumn(unsigned NewCol);
107
108  /// getColumn - Return the column number
109  unsigned getColumn() { return Position.first; }
110
111  /// getLine - Return the line number
112  unsigned getLine() { return Position.second; }
113
114  raw_ostream &resetColor() override {
115    TheStream->resetColor();
116    return *this;
117  }
118
119  raw_ostream &reverseColor() override {
120    TheStream->reverseColor();
121    return *this;
122  }
123
124  raw_ostream &changeColor(enum Colors Color, bool Bold, bool BG) override {
125    TheStream->changeColor(Color, Bold, BG);
126    return *this;
127  }
128
129  bool is_displayed() const override {
130    return TheStream->is_displayed();
131  }
132
133private:
134  void releaseStream() {
135    // Transfer the buffer settings from this raw_ostream back to the underlying
136    // stream.
137    if (!TheStream)
138      return;
139    if (size_t BufferSize = GetBufferSize())
140      TheStream->SetBufferSize(BufferSize);
141    else
142      TheStream->SetUnbuffered();
143  }
144};
145
146/// fouts() - This returns a reference to a formatted_raw_ostream for
147/// standard output.  Use it like: fouts() << "foo" << "bar";
148formatted_raw_ostream &fouts();
149
150/// ferrs() - This returns a reference to a formatted_raw_ostream for
151/// standard error.  Use it like: ferrs() << "foo" << "bar";
152formatted_raw_ostream &ferrs();
153
154/// fdbgs() - This returns a reference to a formatted_raw_ostream for
155/// debug output.  Use it like: fdbgs() << "foo" << "bar";
156formatted_raw_ostream &fdbgs();
157
158} // end llvm namespace
159
160
161#endif
162