FormattedStream.h revision baf2883e0a294fabc059699037ad92822c46bd61 
1//===-- llvm/Support/FormattedStream.h - Formatted streams ------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file contains raw_ostream implementations for streams to do
11// things like pretty-print comments.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_SUPPORT_FORMATTEDSTREAM_H
16#define LLVM_SUPPORT_FORMATTEDSTREAM_H
17
18#include "llvm/Support/raw_ostream.h"
19
20namespace llvm
21{
22  class formatted_tool_output_file;
23
24  /// formatted_raw_ostream - Formatted raw_fd_ostream to handle
25  /// asm-specific constructs.
26  ///
27  class formatted_raw_ostream : public raw_ostream {
28    friend class formatted_tool_output_file;
29
30  public:
31    /// DELETE_STREAM - Tell the destructor to delete the held stream.
32    ///
33    static const bool DELETE_STREAM = true;
34
35    /// PRESERVE_STREAM - Tell the destructor to not delete the held
36    /// stream.
37    ///
38    static const bool PRESERVE_STREAM = false;
39
40  private:
41    /// TheStream - The real stream we output to. We set it to be
42    /// unbuffered, since we're already doing our own buffering.
43    ///
44    raw_ostream *TheStream;
45
46    /// DeleteStream - Do we need to delete TheStream in the
47    /// destructor?
48    ///
49    bool DeleteStream;
50
51    /// ColumnScanned - The current output column of the data that's
52    /// been flushed and the portion of the buffer that's been
53    /// scanned.  The column scheme is zero-based.
54    ///
55    unsigned ColumnScanned;
56
57    /// Scanned - This points to one past the last character in the
58    /// buffer we've scanned.
59    ///
60    const char *Scanned;
61
62    virtual void write_impl(const char *Ptr, size_t Size);
63
64    /// current_pos - Return the current position within the stream,
65    /// not counting the bytes currently in the buffer.
66    virtual uint64_t current_pos() const {
67      // This has the same effect as calling TheStream.current_pos(),
68      // but that interface is private.
69      return TheStream->tell() - TheStream->GetNumBytesInBuffer();
70    }
71
72    /// ComputeColumn - Examine the given output buffer and figure out which
73    /// column we end up in after output.
74    ///
75    void ComputeColumn(const char *Ptr, size_t size);
76
77  public:
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, bool Delete = false)
89      : raw_ostream(), TheStream(0), DeleteStream(false), ColumnScanned(0) {
90      setStream(Stream, Delete);
91    }
92    explicit formatted_raw_ostream()
93      : raw_ostream(), TheStream(0), DeleteStream(false), ColumnScanned(0) {
94      Scanned = 0;
95    }
96
97    ~formatted_raw_ostream() {
98      flush();
99      releaseStream();
100    }
101
102    void setStream(raw_ostream &Stream, bool Delete = false) {
103      releaseStream();
104
105      TheStream = &Stream;
106      DeleteStream = Delete;
107
108      // This formatted_raw_ostream inherits from raw_ostream, so it'll do its
109      // own buffering, and it doesn't need or want TheStream to do another
110      // layer of buffering underneath. Resize the buffer to what TheStream
111      // had been using, and tell TheStream not to do its own buffering.
112      if (size_t BufferSize = TheStream->GetBufferSize())
113        SetBufferSize(BufferSize);
114      else
115        SetUnbuffered();
116      TheStream->SetUnbuffered();
117
118      Scanned = 0;
119    }
120
121    /// PadToColumn - Align the output to some column number.  If the current
122    /// column is already equal to or more than NewCol, PadToColumn inserts one
123    /// space.
124    ///
125    /// \param NewCol - The column to move to.
126    formatted_raw_ostream &PadToColumn(unsigned NewCol);
127
128  private:
129    void releaseStream() {
130      // Delete the stream if needed. Otherwise, transfer the buffer
131      // settings from this raw_ostream back to the underlying stream.
132      if (!TheStream)
133        return;
134      if (DeleteStream)
135        delete TheStream;
136      else if (size_t BufferSize = GetBufferSize())
137        TheStream->SetBufferSize(BufferSize);
138      else
139        TheStream->SetUnbuffered();
140    }
141  };
142
143  /// formatted_tool_output_file - This is a subclass of formatted_raw_ostream
144  /// for use when the underlying stream is a tool_output_file. It exposes
145  /// keep() and several other member functions.
146  class formatted_tool_output_file : public formatted_raw_ostream {
147  private:
148    tool_output_file &get_tool_output_file() const {
149      return *static_cast<tool_output_file *>(TheStream);
150    }
151
152  public:
153    formatted_tool_output_file(tool_output_file &Stream, bool Delete = false)
154      : formatted_raw_ostream(Stream, Delete) {}
155
156    formatted_tool_output_file() {}
157
158    ~formatted_tool_output_file();
159
160    void setStream(tool_output_file &Stream, bool Delete = false) {
161      return formatted_raw_ostream::setStream(Stream, Delete);
162    }
163
164    void keep()            { return get_tool_output_file().keep(); }
165    bool has_error() const { return get_tool_output_file().has_error(); }
166    void clear_error()     { return get_tool_output_file().clear_error(); }
167    void close() {
168      // The inner stream is unbuffered; flush the outer stream's buffer.
169      flush();
170      // The inner stream can close its file descriptor now.
171      return get_tool_output_file().close();
172    }
173  };
174
175/// fouts() - This returns a reference to a formatted_raw_ostream for
176/// standard output.  Use it like: fouts() << "foo" << "bar";
177formatted_raw_ostream &fouts();
178
179/// ferrs() - This returns a reference to a formatted_raw_ostream for
180/// standard error.  Use it like: ferrs() << "foo" << "bar";
181formatted_raw_ostream &ferrs();
182
183/// fdbgs() - This returns a reference to a formatted_raw_ostream for
184/// debug output.  Use it like: fdbgs() << "foo" << "bar";
185formatted_raw_ostream &fdbgs();
186
187} // end llvm namespace
188
189
190#endif
191