gdb/testsuite/tui: Split enter_tui into two procs

Split Term::enter_tui into two procedures, a core which does the
setup, but doesn't actually enable tui mode, and the old enter_tui
that calls the new core, and then enables tui mode.

This is going to be useful in a later commit.

gdb/testsuite/ChangeLog:

	* lib/tuiterm.exp (Term::prepare_for_tui): New proc.
	(Term::enter_tui): Use Term::prepare_for_tui.

Change-Id: I501dfb2ddaa4a4e7246a5ad319ab428e4f42b3af

2 files changed, 18 insertions, 3 deletions

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 6ca5aef..7d8c8d0 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,5 +1,10 @@
 2020-01-09  Andrew Burgess  <andrew.burgess@embecosm.com>
 
+	* lib/tuiterm.exp (Term::prepare_for_tui): New proc.
+	(Term::enter_tui): Use Term::prepare_for_tui.
+
+2020-01-09  Andrew Burgess  <andrew.burgess@embecosm.com>
+
 	* lib/tuiterm.exp (Term::dump_screen): Always dump the screen when
 	called.
 
diff --git a/gdb/testsuite/lib/tuiterm.exp b/gdb/testsuite/lib/tuiterm.exp
index 36e034a..9ac599b 100644
--- a/gdb/testsuite/lib/tuiterm.exp
+++ b/gdb/testsuite/lib/tuiterm.exp
@@ -462,15 +462,25 @@ namespace eval Term {
 	}
     }
 
-    # Start the TUI.  Returns 1 on success, 0 if TUI tests should be
-    # skipped.
-    proc enter_tui {} {
+    # Setup ready for starting the tui, but don't actually start it.
+    # Returns 1 on success, 0 if TUI tests should be skipped.
+    proc prepare_for_tui {} {
 	if {[skip_tui_tests]} {
 	    return 0
 	}
 
 	gdb_test_no_output "set tui border-kind ascii"
 	gdb_test_no_output "maint set tui-resize-message on"
+	return 1
+    }
+
+    # Start the TUI.  Returns 1 on success, 0 if TUI tests should be
+    # skipped.
+    proc enter_tui {} {
+	if {![prepare_for_tui]} {
+	    return 0
+	}
+
 	command "tui enable"
 	return 1
     }