[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, 37 insertions, 0 deletions

diff --git a/gdb/ui-out.h b/gdb/ui-out.h
index 9fc6061..dfd9679 100644
--- a/gdb/ui-out.h
+++ b/gdb/ui-out.h
@@ -275,6 +275,39 @@ class ui_out
      escapes.  */
   virtual bool can_emit_style_escape () const = 0;
 
+  /* An object that starts and finishes a progress meter.  */
+  class progress_meter
+  {
+  public:
+    /* SHOULD_PRINT indicates whether something should be printed for a tty.  */
+    progress_meter (struct ui_out *uiout, const std::string &name,
+		    bool should_print)
+      : m_uiout (uiout)
+    {
+      m_uiout->do_progress_start (name, should_print);
+    }
+
+    ~progress_meter ()
+    {
+      m_uiout->do_progress_notify (1.0);
+      m_uiout->do_progress_end ();
+    }
+
+    progress_meter (const progress_meter &) = delete;
+    progress_meter &operator= (const progress_meter &) = delete;
+
+  private:
+
+    struct ui_out *m_uiout;
+  };
+
+  /* Emit some progress corresponding to the most recently created
+     progress meter.  HOWMUCH may range from 0.0 to 1.0.  */
+  void progress (double howmuch)
+  {
+    do_progress_notify (howmuch);
+  }
+
  protected:
 
   virtual void do_table_begin (int nbrofcols, int nr_rows, const char *tblid)
@@ -309,6 +342,10 @@ class ui_out
   virtual void do_flush () = 0;
   virtual void do_redirect (struct ui_file *outstream) = 0;
 
+  virtual void do_progress_start (const std::string &, bool) = 0;
+  virtual void do_progress_notify (double) = 0;
+  virtual void do_progress_end () = 0;
+
   /* Set as not MI-like by default.  It is overridden in subclasses if
      necessary.  */