[gdb/tui] Fix wrapping strings

I noticed that after resizing to a narrow window, I got:
...
┌────────────────┐
│                │
│[ No Source Avail
able ]           │
│                │
└────────────────┘
...

Fix this by adding two new functions:
- tui_win_info::display_string (int y, int x, const char *str)
- tui_win_info::display_string (const char *str)
that make sure that borders are not overwritten, which get us instead:
...
┌────────────────┐
│                │
│[ No Source Avai│
│                │
│                │
└────────────────┘
...

Tested on x86_64-linux.

2 files changed, 64 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.tui/narrow.exp b/gdb/testsuite/gdb.tui/narrow.exp
new file mode 100644
index 0000000..7407398
--- /dev/null
+++ b/gdb/testsuite/gdb.tui/narrow.exp
@@ -0,0 +1,49 @@
+# Copyright 2023 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 narrow window.
+
+tuiterm_env
+
+# We'd like to start out here with a narrow window, but that's currently not
+# possible.  So instead, we start out with a large one, and resize.
+Term::clean_restart 24 80
+
+if {![Term::enter_tui]} {
+    unsupported "TUI not supported"
+    return
+}
+
+# Disable resize messages.  They are long and will cause wrapping.
+Term::command "maint set tui-resize-message off"
+
+# Scroll previous command off screen.  It is long and will cause wrapping.
+for {set i 0} {$i < 8} {incr i} {
+    Term::command "echo"
+}
+
+Term::check_box "src box" 0 0 80 15
+
+# Resize to narrow screen.
+Term::resize 24 20 0
+
+# Instead of waiting for the resize messages, wait for the resized box.
+Term::wait_for_box "narrow src box" 0 0 20 15
+
+Term::command "layout asm"
+Term::check_box "narrow asm box" 0 0 20 15
+
+Term::command "layout regs"
+Term::check_box "narrow regs box" 0 0 20 8
diff --git a/gdb/testsuite/lib/tuiterm.exp b/gdb/testsuite/lib/tuiterm.exp
index 854fde5..e668fe2 100644
--- a/gdb/testsuite/lib/tuiterm.exp
+++ b/gdb/testsuite/lib/tuiterm.exp
@@ -1102,6 +1102,21 @@ namespace eval Term {
 	}
     }
 
+    # Wait until a box appears at the given coordinates.
+    proc wait_for_box {test_name x y width height} {
+	while 1 {
+	    if { [accept_gdb_output] == 0 } {
+		return 0
+	    }
+
+	    set why [_check_box $x $y $width $height]
+	    if {$why == ""} {
+		pass $test_name
+		break
+	    }
+	}
+    }
+
     # Check whether the text contents of the terminal match the
     # regular expression.  Note that text styling is not considered.
     proc check_contents {test_name regexp} {