Re: [PATCH] Do not emit style escape sequences to log file

[Sergio Durigan Junior <sergiodj at redhat dot com>]

On Thursday, June 06 2019, Tom Tromey wrote:

> PR gdb/24502 requests that the "set logging" log file not contain
> style escape sequences emitted by gdb.
>
> This seemed like a reasonable request to me, so this patch implements
> filtering for the log file.
>
> This also updates a comment in ui-style.h that I noticed while writing
> the patch.
>
> Tested on x86-64 Fedora 29.

Thanks for the patch.

I looked at the code, tried my best to understand what it does
(specially how the "skip_ansi_escape" function interacts with the new
"no_terminal_escape_file::puts" method), and everything looks good to
me.

Thanks.

> gdb/ChangeLog
> 2019-06-06  Tom Tromey  <tromey@adacore.com>
>
> 	PR gdb/24502:
> 	* ui-style.h (skip_ansi_escape): Update comment.
> 	* ui-file.h (class no_terminal_escape_file): New class.
> 	* ui-file.c (no_terminal_escape_file::write)
> 	(no_terminal_escape_file::puts): New methods.
> 	* cli/cli-logging.c (handle_redirections): Use
> 	no_terminal_escape_file.
>
> gdb/testsuite/ChangeLog
> 2019-06-06  Tom Tromey  <tromey@adacore.com>
>
> 	PR gdb/24502:
> 	* gdb.base/style-logging.exp: New file.
> ---
>  gdb/ChangeLog                            | 10 ++++
>  gdb/cli/cli-logging.c                    |  2 +-
>  gdb/testsuite/ChangeLog                  |  5 ++
>  gdb/testsuite/gdb.base/style-logging.exp | 70 ++++++++++++++++++++++++
>  gdb/ui-file.c                            | 32 +++++++++++
>  gdb/ui-file.h                            | 16 ++++++
>  gdb/ui-style.h                           |  4 +-
>  7 files changed, 136 insertions(+), 3 deletions(-)
>  create mode 100644 gdb/testsuite/gdb.base/style-logging.exp
>
> diff --git a/gdb/cli/cli-logging.c b/gdb/cli/cli-logging.c
> index bef5f3939bd..a8b9955c570 100644
> --- a/gdb/cli/cli-logging.c
> +++ b/gdb/cli/cli-logging.c
> @@ -100,7 +100,7 @@ handle_redirections (int from_tty)
>        return;
>      }
>  
> -  stdio_file_up log (new stdio_file ());
> +  stdio_file_up log (new no_terminal_escape_file ());
>    if (!log->open (logging_filename, logging_overwrite ? "w" : "a"))
>      perror_with_name (_("set logging"));
>  
> diff --git a/gdb/testsuite/gdb.base/style-logging.exp b/gdb/testsuite/gdb.base/style-logging.exp
> new file mode 100644
> index 00000000000..1d7c3052c38
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/style-logging.exp
> @@ -0,0 +1,70 @@
> +# Copyright 2019 Free Software Foundation, Inc.
> +
> +# 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/>.
> +
> +# Test that logging does not style.
> +
> +# Do not run if gdb debug is enabled as it will interfere with log redirect.
> +if {[gdb_debug_enabled]} {
> +    untested "debug is enabled"
> +    return 0
> +}
> +
> +if {[is_remote host]} {
> +    untested "does not work on remote host"
> +    return 0
> +}
> +
> +standard_testfile style.c
> +
> +save_vars { env(TERM) } {
> +    # We need an ANSI-capable terminal to get the output.
> +    setenv TERM ansi
> +
> +    if {[prepare_for_testing "failed to prepare" $testfile $srcfile debug]} {
> +	return -1
> +    }
> +
> +    if {![runto_main]} {
> +	fail "style tests failed"
> +	return
> +    }
> +
> +    gdb_test_no_output "set style enabled on"
> +
> +    set log_name [standard_output_file log.txt]
> +    gdb_test_no_output "set logging file $log_name"
> +    gdb_test_no_output "set logging overwrite on"
> +    gdb_test "set logging on" "Copying output to .*"
> +
> +    set main_expr [style main function]
> +    set base_file_expr [style ".*style\\.c" file]
> +    set file_expr "$base_file_expr:\[0-9\]"
> +    set arg_expr [style "arg." variable]
> +    gdb_test "frame" \
> +	"$main_expr.*$arg_expr.*$arg_expr.*$file_expr.*"
> +
> +    gdb_test "set logging off" "Done logging to .*"
> +
> +    set fd [open $log_name]
> +    set data [read -nonewline $fd]
> +    close $fd
> +
> +    set testname "log is escape-free"
> +    if {[regexp "\033" $data]} {
> +	fail $testname
> +    } else {
> +	pass $testname
> +    }
> +}
> diff --git a/gdb/ui-file.c b/gdb/ui-file.c
> index 24c914f442a..05d411aa392 100644
> --- a/gdb/ui-file.c
> +++ b/gdb/ui-file.c
> @@ -396,3 +396,35 @@ tee_file::can_emit_style_escape ()
>  	  && 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));
> +}
> diff --git a/gdb/ui-file.h b/gdb/ui-file.h
> index 39f56d5ea42..3f6f38a68fb 100644
> --- a/gdb/ui-file.h
> +++ b/gdb/ui-file.h
> @@ -287,4 +287,20 @@ private:
>    ui_file_up m_two;
>  };
>  
> +/* A ui_file implementation that filters out terminal escape
> +   sequences.  */
> +
> +class no_terminal_escape_file : public stdio_file
> +{
> +public:
> +  no_terminal_escape_file ()
> +  {
> +  }
> +
> +  /* Like the stdio_file methods, but these filter out terminal escape
> +     sequences.  */
> +  void write (const char *buf, long length_buf) override;
> +  void puts (const char *linebuffer) override;
> +};
> +
>  #endif
> diff --git a/gdb/ui-style.h b/gdb/ui-style.h
> index 2a87fbe8012..24b4b59ed9f 100644
> --- a/gdb/ui-style.h
> +++ b/gdb/ui-style.h
> @@ -233,8 +233,8 @@ private:
>  
>  /* Skip an ANSI escape sequence in BUF.  BUF must begin with an ESC
>     character.  Return true if an escape sequence was successfully
> -   skipped; false otherwise.  In either case, N_READ is updated to
> -   reflect the number of chars read from BUF.  */
> +   skipped; false otherwise.  If an escape sequence was skipped,
> +   N_READ is updated to reflect the number of chars read from BUF.  */
>  
>  extern bool skip_ansi_escape (const char *buf, int *n_read);
>  
> -- 
> 2.20.1

-- 
Sergio
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