1 /* UI_FILE - a generic STDIO like output stream.
2 Copyright (C) 1999-2020 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/>. */
25 /* The abstract ui_file base class. */
31 virtual ~ui_file () = 0;
33 /* Public non-virtual API. */
35 void printf (const char *, ...) ATTRIBUTE_PRINTF (2, 3);
37 /* Print a string whose delimiter is QUOTER. Note that these
38 routines should only be called for printing things which are
39 independent of the language of the program being debugged. */
40 void putstr (const char *str
, int quoter
);
42 void putstrn (const char *str
, int n
, int quoter
);
46 void vprintf (const char *, va_list) ATTRIBUTE_PRINTF (2, 0);
48 /* Methods below are both public, and overridable by ui_file
51 virtual void write (const char *buf
, long length_buf
) = 0;
53 /* This version of "write" is safe for use in signal handlers. It's
54 not guaranteed that all existing output will have been flushed
55 first. Implementations are also free to ignore some or all of
56 the request. puts_async is not provided as the async versions
57 are rarely used, no point in having both for a rarely used
59 virtual void write_async_safe (const char *buf
, long length_buf
)
60 { gdb_assert_not_reached ("write_async_safe"); }
62 /* Some ui_files override this to provide a efficient implementation
63 that avoids a strlen. */
64 virtual void puts (const char *str
)
65 { this->write (str
, strlen (str
)); }
67 virtual long read (char *buf
, long length_buf
)
68 { gdb_assert_not_reached ("can't read from this file type"); }
70 virtual bool isatty ()
73 /* true indicates terminal output behaviour such as cli_styling.
74 This default implementation indicates to do terminal output
75 behaviour if the UI_FILE is a tty. A derived class can override
76 TERM_OUT to have cli_styling behaviour without being a tty. */
77 virtual bool term_out ()
80 /* true if ANSI escapes can be used on STREAM. */
81 virtual bool can_emit_style_escape ()
88 typedef std::unique_ptr
<ui_file
> ui_file_up
;
90 /* A ui_file that writes to nowhere. */
92 class null_file
: public ui_file
95 void write (const char *buf
, long length_buf
) override
;
96 void write_async_safe (const char *buf
, long sizeof_buf
) override
;
97 void puts (const char *str
) override
;
100 /* A preallocated null_file stream. */
101 extern null_file null_stream
;
103 extern void ui_file_flush (ui_file
*);
105 extern int ui_file_isatty (struct ui_file
*);
107 extern void ui_file_write (struct ui_file
*file
, const char *buf
,
110 extern void ui_file_write_async_safe (struct ui_file
*file
, const char *buf
,
113 extern long ui_file_read (struct ui_file
*file
, char *buf
, long length_buf
);
115 extern int gdb_console_fputs (const char *, FILE *);
117 /* A std::string-based ui_file. Can be used as a scratch buffer for
118 collecting output. */
120 class string_file
: public ui_file
123 /* Construct a string_file to collect 'raw' output, i.e. without
124 'terminal' behaviour such as cli_styling. */
125 string_file () : m_term_out (false) {};
126 /* If TERM_OUT, construct a string_file with terminal output behaviour
128 else collect 'raw' output like the previous constructor. */
129 explicit string_file (bool term_out
) : m_term_out (term_out
) {};
130 ~string_file () override
;
132 /* Override ui_file methods. */
134 void write (const char *buf
, long length_buf
) override
;
136 long read (char *buf
, long length_buf
) override
137 { gdb_assert_not_reached ("a string_file is not readable"); }
139 bool term_out () override
;
140 bool can_emit_style_escape () override
;
142 /* string_file-specific public API. */
144 /* Accesses the std::string containing the entire output collected
147 Returns a non-const reference so that it's easy to move the
148 string contents out of the string_file. E.g.:
153 return std::move (buf.string ());
155 std::string
&string () { return m_string
; }
157 /* Provide a few convenience methods with the same API as the
158 underlying std::string. */
159 const char *data () const { return m_string
.data (); }
160 const char *c_str () const { return m_string
.c_str (); }
161 size_t size () const { return m_string
.size (); }
162 bool empty () const { return m_string
.empty (); }
163 void clear () { return m_string
.clear (); }
166 /* The internal buffer. */
167 std::string m_string
;
172 /* A ui_file implementation that maps directly onto <stdio.h>'s FILE.
173 A stdio_file can either own its underlying file, or not. If it
174 owns the file, then destroying the stdio_file closes the underlying
175 file, otherwise it is left open. */
177 class stdio_file
: public ui_file
180 /* Create a ui_file from a previously opened FILE. CLOSE_P
181 indicates whether the underlying file should be closed when the
182 stdio_file is destroyed. */
183 explicit stdio_file (FILE *file
, bool close_p
= false);
185 /* Create an stdio_file that is not managing any file yet. Call
186 open to actually open something. */
189 ~stdio_file () override
;
191 /* Open NAME in mode MODE, and own the resulting file. Returns true
192 on success, false otherwise. If the stdio_file previously owned
193 a file, it is closed. */
194 bool open (const char *name
, const char *mode
);
196 void flush () override
;
198 void write (const char *buf
, long length_buf
) override
;
200 void write_async_safe (const char *buf
, long length_buf
) override
;
202 void puts (const char *) override
;
204 long read (char *buf
, long length_buf
) override
;
206 bool isatty () override
;
208 bool can_emit_style_escape () override
;
211 /* Sets the internal stream to FILE, and saves the FILE's file
212 descriptor in M_FD. */
213 void set_stream (FILE *file
);
218 /* The associated file descriptor is extracted ahead of time for
219 stdio_file::write_async_safe's benefit, in case fileno isn't
223 /* If true, M_FILE is closed on destruction. */
227 typedef std::unique_ptr
<stdio_file
> stdio_file_up
;
229 /* Like stdio_file, but specifically for stderr.
231 This exists because there is no real line-buffering on Windows, see
232 <http://msdn.microsoft.com/en-us/library/86cebhfs%28v=vs.71%29.aspx>
233 so the stdout is either fully-buffered or non-buffered. We can't
234 make stdout non-buffered, because of two concerns:
236 1. Non-buffering hurts performance.
237 2. Non-buffering may change GDB's behavior when it is interacting
238 with a front-end, such as Emacs.
240 We leave stdout as fully buffered, but flush it first when
241 something is written to stderr.
243 Note that the 'write_async_safe' method is not overridden, because
244 there's no way to flush a stream in an async-safe manner.
245 Fortunately, it doesn't really matter, because:
247 1. That method is only used for printing internal debug output
248 from signal handlers.
250 2. Windows hosts don't have a concept of async-safeness. Signal
251 handlers run in a separate thread, so they can call the regular
252 non-async-safe output routines freely.
254 class stderr_file
: public stdio_file
257 explicit stderr_file (FILE *stream
);
259 /* Override the output routines to flush gdb_stdout before deferring
260 to stdio_file for the actual outputting. */
261 void write (const char *buf
, long length_buf
) override
;
262 void puts (const char *linebuffer
) override
;
265 /* A ui_file implementation that maps onto two ui-file objects. */
267 class tee_file
: public ui_file
270 /* Create a file which writes to both ONE and TWO. ONE will remain
271 open when this object is destroyed; but TWO will be closed. */
272 tee_file (ui_file
*one
, ui_file_up
&&two
);
273 ~tee_file () override
;
275 void write (const char *buf
, long length_buf
) override
;
276 void write_async_safe (const char *buf
, long length_buf
) override
;
277 void puts (const char *) override
;
279 bool isatty () override
;
280 bool term_out () override
;
281 bool can_emit_style_escape () override
;
282 void flush () override
;
285 /* The two underlying ui_files. */
290 /* A ui_file implementation that filters out terminal escape
293 class no_terminal_escape_file
: public stdio_file
296 no_terminal_escape_file ()
300 /* Like the stdio_file methods, but these filter out terminal escape
302 void write (const char *buf
, long length_buf
) override
;
303 void puts (const char *linebuffer
) override
;