Files
binutils-gdb/gdb/ui-file.c
Andrew Burgess 431b369e1c gdb/styling: only check TERM environment once, during initialisation
We currently check the TERM environment variable any time we call one
of the ui_file::can_emit_style_escape() functions.  This seems
excessive.

During GDB's startup we also check for the NO_COLOR environment
variable and disable styling if this is set.

I propose that we combine these two checks, and perform them just once
during startup (as the current NO_COLOR check is currently done).  As
with the NO_COLOR check, if the TERM variable is set to "dumb"
indicating that styling is not supported then we should just set
cli_styling to false.

This does mean that the user can then 'set style enabled on', even for
a dumb terminal, which was not possible previously.  Before this
commit the "dumb" terminal check was separate and would prevent
styling even if 'set style enabled on' was in effect.

Of course, trying to turn on styling in a dumb terminal might not give
the results that a user hope for.  And so, I have implemented a check
in `set_style_enabled`, so in a dumb terminal a user will see this:

  (gdb) set style enabled on
  warning: The current terminal doesn't support styling.  Styled output might not appear as expected.

After which GDB will try to emit styling.  We could, potentially,
prevent styling being enabled instead of emitting a warning, but I'm
inclined to let the user turn on styling if they really want to.

Approved-By: Kevin Buettner <kevinb@redhat.com>
Acked-By: Tom Tromey <tom@tromey.com>
2025-02-24 17:03:18 +00:00

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/* UI_FILE - a generic STDIO like output stream.
Copyright (C) 1999-2024 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* Implement the ``struct ui_file'' object. */
#include "ui-file.h"
#include "gdbsupport/gdb_obstack.h"
#include "gdbsupport/gdb_select.h"
#include "gdbsupport/filestuff.h"
#include "cli-out.h"
#include "cli/cli-style.h"
#include <chrono>
null_file null_stream;
ui_file::ui_file ()
{}
ui_file::~ui_file ()
{}
void
ui_file::printf (const char *format, ...)
{
va_list args;
va_start (args, format);
vprintf (format, args);
va_end (args);
}
void
ui_file::putstr (const char *str, int quoter)
{
while (*str)
printchar (*str++, quoter, false);
}
void
ui_file::putstrn (const char *str, int n, int quoter, bool async_safe)
{
for (int i = 0; i < n; i++)
printchar (str[i], quoter, async_safe);
}
void
ui_file::putc (int c)
{
char copy = (char) c;
write (&copy, 1);
}
void
ui_file::vprintf (const char *format, va_list args)
{
ui_out_flags flags = disallow_ui_out_field;
cli_ui_out (this, flags).vmessage (m_applied_style, format, args);
}
/* See ui-file.h. */
void
ui_file::emit_style_escape (const ui_file_style &style)
{
if (can_emit_style_escape () && style != m_applied_style)
{
m_applied_style = style;
this->puts (style.to_ansi ().c_str ());
}
}
/* See ui-file.h. */
void
ui_file::reset_style ()
{
if (can_emit_style_escape ())
{
m_applied_style = ui_file_style ();
this->puts (m_applied_style.to_ansi ().c_str ());
}
}
/* See ui-file.h. */
void
ui_file::printchar (int c, int quoter, bool async_safe)
{
char buf[4];
int out = 0;
c &= 0xFF; /* Avoid sign bit follies */
if (c < 0x20 /* Low control chars */
|| (c >= 0x7F && c < 0xA0) /* DEL, High controls */
|| (sevenbit_strings && c >= 0x80))
{ /* high order bit set */
buf[out++] = '\\';
switch (c)
{
case '\n':
buf[out++] = 'n';
break;
case '\b':
buf[out++] = 'b';
break;
case '\t':
buf[out++] = 't';
break;
case '\f':
buf[out++] = 'f';
break;
case '\r':
buf[out++] = 'r';
break;
case '\033':
buf[out++] = 'e';
break;
case '\007':
buf[out++] = 'a';
break;
default:
{
buf[out++] = '0' + ((c >> 6) & 0x7);
buf[out++] = '0' + ((c >> 3) & 0x7);
buf[out++] = '0' + ((c >> 0) & 0x7);
break;
}
}
}
else
{
if (quoter != 0 && (c == '\\' || c == quoter))
buf[out++] = '\\';
buf[out++] = c;
}
if (async_safe)
this->write_async_safe (buf, out);
else
this->write (buf, out);
}
void
null_file::write (const char *buf, long sizeof_buf)
{
/* Discard the request. */
}
void
null_file::puts (const char *)
{
/* Discard the request. */
}
void
null_file::write_async_safe (const char *buf, long sizeof_buf)
{
/* Discard the request. */
}
/* Return true if styling is currently enabled. */
static bool
term_cli_styling ()
{
return cli_styling;
}
string_file::~string_file ()
{}
void
string_file::write (const char *buf, long length_buf)
{
m_string.append (buf, length_buf);
}
/* See ui-file.h. */
bool
string_file::term_out ()
{
return m_term_out;
}
/* See ui-file.h. */
bool
string_file::can_emit_style_escape ()
{
return m_term_out && term_cli_styling ();
}
stdio_file::stdio_file (FILE *file, bool close_p)
{
set_stream (file);
m_close_p = close_p;
}
stdio_file::stdio_file ()
: m_file (NULL),
m_fd (-1),
m_close_p (false)
{}
stdio_file::~stdio_file ()
{
if (m_close_p)
fclose (m_file);
}
void
stdio_file::set_stream (FILE *file)
{
m_file = file;
m_fd = fileno (file);
}
bool
stdio_file::open (const char *name, const char *mode)
{
/* Close the previous stream, if we own it. */
if (m_close_p)
{
fclose (m_file);
m_close_p = false;
}
gdb_file_up f = gdb_fopen_cloexec (name, mode);
if (f == NULL)
return false;
set_stream (f.release ());
m_close_p = true;
return true;
}
void
stdio_file::flush ()
{
fflush (m_file);
}
long
stdio_file::read (char *buf, long length_buf)
{
/* Wait until at least one byte of data is available, or we get
interrupted with Control-C. */
{
fd_set readfds;
FD_ZERO (&readfds);
FD_SET (m_fd, &readfds);
if (interruptible_select (m_fd + 1, &readfds, NULL, NULL, NULL) == -1)
return -1;
}
return ::read (m_fd, buf, length_buf);
}
void
stdio_file::write (const char *buf, long length_buf)
{
/* Calling error crashes when we are called from the exception framework. */
if (fwrite (buf, length_buf, 1, m_file))
{
/* Nothing. */
}
}
void
stdio_file::write_async_safe (const char *buf, long length_buf)
{
/* This is written the way it is to avoid a warning from gcc about not using the
result of write (since it can be declared with attribute warn_unused_result).
Alas casting to void doesn't work for this. */
if (::write (m_fd, buf, length_buf))
{
/* Nothing. */
}
}
void
stdio_file::puts (const char *linebuffer)
{
/* This host-dependent function (with implementations in
posix-hdep.c and mingw-hdep.c) is given the opportunity to
process the output first in host-dependent way. If it does, it
should return non-zero, to avoid calling fputs below. */
if (gdb_console_fputs (linebuffer, m_file))
return;
/* Calling error crashes when we are called from the exception framework. */
if (fputs (linebuffer, m_file))
{
/* Nothing. */
}
}
bool
stdio_file::isatty ()
{
return ::isatty (m_fd);
}
/* See ui-file.h. */
bool
stdio_file::can_emit_style_escape ()
{
return (this->isatty ()
&& term_cli_styling ());
}
/* This is the implementation of ui_file method 'write' for stderr.
gdb_stdout is flushed before writing to gdb_stderr. */
void
stderr_file::write (const char *buf, long length_buf)
{
gdb_stdout->flush ();
stdio_file::write (buf, length_buf);
}
/* This is the implementation of ui_file method 'puts' for stderr.
gdb_stdout is flushed before writing to gdb_stderr. */
void
stderr_file::puts (const char *linebuffer)
{
gdb_stdout->flush ();
stdio_file::puts (linebuffer);
}
stderr_file::stderr_file (FILE *stream)
: stdio_file (stream)
{}
tee_file::tee_file (ui_file *one, ui_file *two)
: m_one (one),
m_two (two)
{}
tee_file::~tee_file ()
{
}
void
tee_file::flush ()
{
m_one->flush ();
m_two->flush ();
}
void
tee_file::write (const char *buf, long length_buf)
{
m_one->write (buf, length_buf);
m_two->write (buf, length_buf);
}
void
tee_file::write_async_safe (const char *buf, long length_buf)
{
m_one->write_async_safe (buf, length_buf);
m_two->write_async_safe (buf, length_buf);
}
void
tee_file::puts (const char *linebuffer)
{
m_one->puts (linebuffer);
m_two->puts (linebuffer);
}
bool
tee_file::isatty ()
{
return m_one->isatty ();
}
/* See ui-file.h. */
bool
tee_file::term_out ()
{
return m_one->term_out ();
}
/* See ui-file.h. */
bool
tee_file::can_emit_style_escape ()
{
return (m_one->term_out ()
&& term_cli_styling ());
}
/* See ui-file.h. */
void
no_terminal_escape_file::write (const char *buf, long length_buf)
{
std::string copy (buf, length_buf);
this->puts (copy.c_str ());
}
/* See ui-file.h. */
void
no_terminal_escape_file::puts (const char *buf)
{
while (*buf != '\0')
{
const char *esc = strchr (buf, '\033');
if (esc == nullptr)
break;
int n_read = 0;
if (!skip_ansi_escape (esc, &n_read))
++esc;
this->stdio_file::write (buf, esc - buf);
buf = esc + n_read;
}
if (*buf != '\0')
this->stdio_file::write (buf, strlen (buf));
}
void
timestamped_file::write (const char *buf, long len)
{
if (debug_timestamp)
{
/* Print timestamp if previous print ended with a \n. */
if (m_needs_timestamp)
{
using namespace std::chrono;
steady_clock::time_point now = steady_clock::now ();
seconds s = duration_cast<seconds> (now.time_since_epoch ());
microseconds us = duration_cast<microseconds> (now.time_since_epoch () - s);
std::string timestamp = string_printf ("%ld.%06ld ",
(long) s.count (),
(long) us.count ());
m_stream->puts (timestamp.c_str ());
}
/* Print the message. */
m_stream->write (buf, len);
m_needs_timestamp = (len > 0 && buf[len - 1] == '\n');
}
else
m_stream->write (buf, len);
}