[gdb/cli] Add a progress meter

Add a progress meter.  It's not used anywhere yet.

gdb/ChangeLog:

2020-12-16  Tom Tromey  <tom@tromey.com>
	    Tom Tromey  <tromey@redhat.com>
	    Tom de Vries  <tdevries@suse.de>

	* utils.h (get_chars_per_line): Declare.
	* utils.c (get_chars_per_line): New function.
	(fputs_maybe_filtered): Handle '\r'.
	* ui-out.h (ui_out::progress_meter): New class.
	(ui_out::progress, ui_out::do_progress_start)
	(ui_out::do_progress_notify, ui_out::do_progress_end): New
	methods.
	* ui-out.c (do_progress_end)
	(make_cleanup_ui_out_progress_begin_end, ui_out_progress): New
	functions.
	* mi/mi-out.h (mi_ui_out::do_progress_start)
	(mi_ui_out::do_progress_notify, mi_ui_out::do_progress_end): New
	methods.
	* cli-out.h (struct cli_ui_out) <do_progress_start,
	do_progress_notify, do_progress_end>: New methods.
	<enum meter_stat, struct cli_progress_info>: New.
	<m_meters>: New member.
	* cli-out.c (cli_ui_out::do_progress_start)
	(cli_ui_out::do_progress_notify, cli_ui_out::do_progress_end): New
	methods.

1 files changed, 101 insertions, 0 deletions

diff --git a/gdb/cli-out.c b/gdb/cli-out.c
index e47272a..7722ecc 100644
--- a/gdb/cli-out.c
+++ b/gdb/cli-out.c
@@ -265,6 +265,107 @@ cli_ui_out::do_redirect (ui_file *outstream)
     m_streams.pop_back ();
 }
 
+/* The cli_ui_out::do_progress_* functions result in the following:
+   - printed for tty, SHOULD_PRINT == true:
+     <NAME
+      [#####                      ]\r>
+   - printed for tty, SHOULD_PRINT == false:
+     <>
+   - printed for not-a-tty:
+     <NAME...done.
+     >
+*/
+
+void
+cli_ui_out::do_progress_start (const std::string &name, bool should_print)
+{
+  struct ui_file *stream = m_streams.back ();
+  cli_progress_info meter;
+
+  meter.last_value = 0;
+  meter.name = name;
+  if (!stream->isatty ())
+    {
+      fprintf_unfiltered (stream, "%s...", meter.name.c_str ());
+      gdb_flush (stream);
+      meter.printing = WORKING;
+    }
+  else
+    {
+      /* Don't actually emit anything until the first call notifies us
+	 of progress.  This makes it so a second progress message can
+	 be started before the first one has been notified, without
+	 messy output.  */
+      meter.printing = should_print ? START : NO_PRINT;
+    }
+
+  m_meters.push_back (std::move (meter));
+}
+
+void
+cli_ui_out::do_progress_notify (double howmuch)
+{
+  struct ui_file *stream = m_streams.back ();
+  cli_progress_info &meter (m_meters.back ());
+
+  if (meter.printing == NO_PRINT)
+    return;
+
+  if (meter.printing == START)
+    {
+      fprintf_unfiltered (stream, "%s\n", meter.name.c_str ());
+      gdb_flush (stream);
+      meter.printing = WORKING;
+    }
+
+  if (meter.printing == WORKING && howmuch >= 1.0)
+    return;
+
+  if (!stream->isatty ())
+    return;
+
+  int chars_per_line = get_chars_per_line ();
+  if (chars_per_line > 0)
+    {
+      int i, max;
+      int width = chars_per_line - 3;
+
+      max = width * howmuch;
+      fprintf_unfiltered (stream, "\r[");
+      for (i = 0; i < width; ++i)
+	fprintf_unfiltered (stream, i < max ? "#" : " ");
+      fprintf_unfiltered (stream, "]");
+      gdb_flush (stream);
+      meter.printing = PROGRESS;
+    }
+}
+
+void
+cli_ui_out::do_progress_end ()
+{
+  struct ui_file *stream = m_streams.back ();
+  cli_progress_info &meter = m_meters.back ();
+
+  if (!stream->isatty ())
+    {
+      fprintf_unfiltered (stream, "done.\n");
+      gdb_flush (stream);
+    }
+  else if (meter.printing == PROGRESS)
+    {
+      int i;
+      int width = get_chars_per_line () - 3;
+
+      fprintf_unfiltered (stream, "\r");
+      for (i = 0; i < width + 2; ++i)
+	fprintf_unfiltered (stream, " ");
+      fprintf_unfiltered (stream, "\r");
+      gdb_flush (stream);
+    }
+
+  m_meters.pop_back ();
+}
+
 /* local functions */
 
 void