Have 'thread|frame apply' style their output.

'thread|frame apply CMD' launches CMD so that CMD output goes to a string_file.
This patch ensures that string_file for such CMD output contains
style escape sequences that 'thread|frame apply' will later on
output on the real terminal, so as to have CMD output properly styled.

The idea is to have the class ui_file having overridable methods
to indicate that the output to this ui_file should be done using
'terminal' behaviour such as styling.
Then these methods are overriden in string_file so that a specially
constructed string_file will get output with style escape sequences.

After this patch, the output of CMD by thread|frame apply CMD is styled
similarly as when CMD is launched directly.
Note that string_file (term_out true) could also support wrapping,
but this is not done (yet?).

Tested on debian/amd64.

gdb/ChangeLog
2019-04-27  Philippe Waroquiers  <philippe.waroquiers@skynet.be>

	Support style in 'frame|thread apply'

	* gdbcmd.h (execute_command_to_string): New term_out parameter.
	* record.c (record_start, record_stop): Update callers of
	execute_command_to_string with false.
	* ui-file.h (class ui_file): New term_out and can_emit_style_escape
	methods.
	(class string_file): New constructor with term_out parameter.
	Override methods term_out and can_emit_style_escape.  New member
	term_out.
	(class stdio_file): Override can_emit_style_escape.
	(class tee_file): Override term_out and can_emit_style_escape.
	* utils.h (can_emit_style_escape): Remove.
	* utils.c (can_emit_style_escape): Likewise.
	Update all callers of can_emit_style_escape (SOMESTREAM) to
	SOMESTREAM->can_emit_style_escape.
	* source-cache.c (source_cache::get_source_lines): Likewise.
	* stack.c (frame_apply_command_count): Call execute_command_to_string
	passing the term_out characteristic of the current gdb_stdout.
	* thread.c (thr_try_catch_cmd): Likewise.
	* top.c (execute_command_to_string): pass term_out parameter
	to construct the string_file for the command output.
	* ui-file.c (term_cli_styling): New function (most code moved
	from utils.c can_emit_style_escape).
	(string_file::string_file, string_file::can_emit_style_escape,
	stdio_file::can_emit_style_escape, tee_file::term_out,
	tee_file::can_emit_style_escape): New functions.

1 files changed, 5 insertions, 30 deletions

diff --git a/gdb/utils.c b/gdb/utils.c
index fa7a2674ef7..fd4427d4e6c 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -1435,38 +1435,13 @@ emit_style_escape (const ui_file_style &style,
     fputs_unfiltered (style.to_ansi ().c_str (), stream);
 }
 
-/* See utils.h.  */
-
-bool
-can_emit_style_escape (struct ui_file *stream)
-{
-  if (stream != gdb_stdout
-      || !cli_styling
-      || !ui_file_isatty (stream))
-    return false;
-  const char *term = getenv ("TERM");
-  /* Windows doesn't by default define $TERM, but can support styles
-     regardless.  */
-#ifndef _WIN32
-  if (term == nullptr || !strcmp (term, "dumb"))
-    return false;
-#else
-  /* But if they do define $TERM, let us behave the same as on Posix
-     platforms, for the benefit of programs which invoke GDB as their
-     back-end.  */
-  if (term && !strcmp (term, "dumb"))
-    return false;
-#endif
-  return true;
-}
-
 /* Set the current output style.  This will affect future uses of the
    _filtered output functions.  */
 
 static void
 set_output_style (struct ui_file *stream, const ui_file_style &style)
 {
-  if (!can_emit_style_escape (stream))
+  if (!stream->can_emit_style_escape ())
     return;
 
   /* Note that we don't pass STREAM here, because we want to emit to
@@ -1479,7 +1454,7 @@ set_output_style (struct ui_file *stream, const ui_file_style &style)
 void
 reset_terminal_style (struct ui_file *stream)
 {
-  if (can_emit_style_escape (stream))
+  if (stream->can_emit_style_escape ())
     {
       /* Force the setting, regardless of what we think the setting
 	 might already be.  */
@@ -1504,7 +1479,7 @@ prompt_for_continue (void)
   bool disable_pagination = pagination_disabled_for_command;
 
   /* Clear the current styling.  */
-  if (can_emit_style_escape (gdb_stdout))
+  if (gdb_stdout->can_emit_style_escape ())
     emit_style_escape (ui_file_style (), gdb_stdout);
 
   if (annotation_level > 1)
@@ -1801,7 +1776,7 @@ fputs_maybe_filtered (const char *linebuffer, struct ui_file *stream,
 	      lines_printed++;
 	      if (wrap_column)
 		{
-		  if (can_emit_style_escape (stream))
+		  if (stream->can_emit_style_escape ())
 		    emit_style_escape (ui_file_style (), stream);
 		  /* If we aren't actually wrapping, don't output
 		     newline -- if chars_per_line is right, we
@@ -1823,7 +1798,7 @@ fputs_maybe_filtered (const char *linebuffer, struct ui_file *stream,
 	      if (wrap_column)
 		{
 		  fputs_unfiltered (wrap_indent, stream);
-		  if (can_emit_style_escape (stream))
+		  if (stream->can_emit_style_escape ())
 		    emit_style_escape (wrap_style, stream);
 		  /* FIXME, this strlen is what prevents wrap_indent from
 		     containing tabs.  However, if we recurse to print it