1 /* UI_FILE - a generic STDIO like output stream.
2 Copyright (C) 1999-2017 Free Software Foundation, Inc.
4 This file is part of GDB.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 /* The abstract ui_file base class. */
30 virtual ~ui_file () = 0;
32 /* Public non-virtual API. */
34 void printf (const char *, ...) ATTRIBUTE_PRINTF (2, 3);
36 /* Print a string whose delimiter is QUOTER. Note that these
37 routines should only be called for printing things which are
38 independent of the language of the program being debugged. */
39 void putstr (const char *str
, int quoter
);
41 void putstrn (const char *str
, int n
, int quoter
);
45 void vprintf (const char *, va_list) ATTRIBUTE_PRINTF (2, 0);
47 /* Methods below are both public, and overridable by ui_file
50 virtual void write (const char *buf
, long length_buf
) = 0;
52 /* This version of "write" is safe for use in signal handlers. It's
53 not guaranteed that all existing output will have been flushed
54 first. Implementations are also free to ignore some or all of
55 the request. puts_async is not provided as the async versions
56 are rarely used, no point in having both for a rarely used
58 virtual void write_async_safe (const char *buf
, long length_buf
)
59 { gdb_assert_not_reached ("write_async_safe"); }
61 /* Some ui_files override this to provide a efficient implementation
62 that avoids a strlen. */
63 virtual void puts (const char *str
)
64 { this->write (str
, strlen (str
)); }
66 virtual long read (char *buf
, long length_buf
)
67 { gdb_assert_not_reached ("can't read from this file type"); }
69 virtual bool isatty ()
76 typedef std::unique_ptr
<ui_file
> ui_file_up
;
78 /* A ui_file that writes to nowhere. */
80 class null_file
: public ui_file
83 void write (const char *buf
, long length_buf
) override
;
84 void write_async_safe (const char *buf
, long sizeof_buf
) override
;
85 void puts (const char *str
) override
;
88 /* A preallocated null_file stream. */
89 extern null_file null_stream
;
91 extern void gdb_flush (ui_file
*);
93 extern int ui_file_isatty (struct ui_file
*);
95 extern void ui_file_write (struct ui_file
*file
, const char *buf
,
98 extern void ui_file_write_async_safe (struct ui_file
*file
, const char *buf
,
101 extern long ui_file_read (struct ui_file
*file
, char *buf
, long length_buf
);
103 /* A std::string-based ui_file. Can be used as a scratch buffer for
104 collecting output. */
106 class string_file
: public ui_file
110 ~string_file () override
;
112 /* Override ui_file methods. */
114 void write (const char *buf
, long length_buf
) override
;
116 long read (char *buf
, long length_buf
) override
117 { gdb_assert_not_reached ("a string_file is not readable"); }
119 /* string_file-specific public API. */
121 /* Accesses the std::string containing the entire output collected
124 Returns a non-const reference so that it's easy to move the
125 string contents out of the string_file. E.g.:
130 return std::move (buf.string ());
132 std::string
&string () { return m_string
; }
134 /* Provide a few convenience methods with the same API as the
135 underlying std::string. */
136 const char *data () const { return m_string
.data (); }
137 const char *c_str () const { return m_string
.c_str (); }
138 size_t size () const { return m_string
.size (); }
139 bool empty () const { return m_string
.empty (); }
140 void clear () { return m_string
.clear (); }
143 /* The internal buffer. */
144 std::string m_string
;
147 /* A ui_file implementation that maps directly onto <stdio.h>'s FILE.
148 A stdio_file can either own its underlying file, or not. If it
149 owns the file, then destroying the stdio_file closes the underlying
150 file, otherwise it is left open. */
152 class stdio_file
: public ui_file
155 /* Create a ui_file from a previously opened FILE. CLOSE_P
156 indicates whether the underlying file should be closed when the
157 stdio_file is destroyed. */
158 explicit stdio_file (FILE *file
, bool close_p
= false);
160 /* Create an stdio_file that is not managing any file yet. Call
161 open to actually open something. */
164 ~stdio_file () override
;
166 /* Open NAME in mode MODE, and own the resulting file. Returns true
167 on success, false otherwise. If the stdio_file previously owned
168 a file, it is closed. */
169 bool open (const char *name
, const char *mode
);
171 void flush () override
;
173 void write (const char *buf
, long length_buf
) override
;
175 void write_async_safe (const char *buf
, long length_buf
) override
;
177 void puts (const char *) override
;
179 long read (char *buf
, long length_buf
) override
;
181 bool isatty () override
;
184 /* Sets the internal stream to FILE, and saves the FILE's file
185 descriptor in M_FD. */
186 void set_stream (FILE *file
);
191 /* The associated file descriptor is extracted ahead of time for
192 stdio_file::write_async_safe's benefit, in case fileno isn't
196 /* If true, M_FILE is closed on destruction. */
200 typedef std::unique_ptr
<stdio_file
> stdio_file_up
;
202 /* Like stdio_file, but specifically for stderr.
204 This exists because there is no real line-buffering on Windows, see
205 <http://msdn.microsoft.com/en-us/library/86cebhfs%28v=vs.71%29.aspx>
206 so the stdout is either fully-buffered or non-buffered. We can't
207 make stdout non-buffered, because of two concerns:
209 1. Non-buffering hurts performance.
210 2. Non-buffering may change GDB's behavior when it is interacting
211 with a front-end, such as Emacs.
213 We leave stdout as fully buffered, but flush it first when
214 something is written to stderr.
216 Note that the 'write_async_safe' method is not overridden, because
217 there's no way to flush a stream in an async-safe manner.
218 Fortunately, it doesn't really matter, because:
220 1. That method is only used for printing internal debug output
221 from signal handlers.
223 2. Windows hosts don't have a concept of async-safeness. Signal
224 handlers run in a separate thread, so they can call the regular
225 non-async-safe output routines freely.
227 class stderr_file
: public stdio_file
230 explicit stderr_file (FILE *stream
);
232 /* Override the output routines to flush gdb_stdout before deferring
233 to stdio_file for the actual outputting. */
234 void write (const char *buf
, long length_buf
) override
;
235 void puts (const char *linebuffer
) override
;
238 /* A ui_file implementation that maps onto two ui-file objects. */
240 class tee_file
: public ui_file
243 /* Create a file which writes to both ONE and TWO. CLOSE_ONE and
244 CLOSE_TWO indicate whether the original files should be closed
245 when the new file is closed. */
246 tee_file (ui_file
*one
, bool close_one
,
247 ui_file
*two
, bool close_two
);
248 ~tee_file () override
;
250 void write (const char *buf
, long length_buf
) override
;
251 void write_async_safe (const char *buf
, long length_buf
) override
;
252 void puts (const char *) override
;
254 bool isatty () override
;
255 void flush () override
;
258 /* The two underlying ui_files, and whether they should each be
259 closed on destruction. */
260 ui_file
*m_one
, *m_two
;
261 bool m_close_one
, m_close_two
;
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