gdb/tui: better filtering of tab completion results for focus command

While working on the previous couple of commits, I noticed that the
'focus' command would happily suggest 'status' as a possible focus
completion, even though the 'status' window is non-focusable, and,
after the previous couple of commits, trying to focus the status
window will result in an error.

This commit improves the tab-completion results for the focus command
so that the status window is not included.

2 files changed, 33 insertions, 9 deletions

diff --git a/gdb/testsuite/gdb.tui/completion.exp b/gdb/testsuite/gdb.tui/completion.exp
index a3b3114a472..97d0f806a81 100644
--- a/gdb/testsuite/gdb.tui/completion.exp
+++ b/gdb/testsuite/gdb.tui/completion.exp
@@ -15,8 +15,9 @@
 
 require allow_tui_tests
 
-gdb_exit
-gdb_start
+tuiterm_env
+
+clean_restart
 
 if {[target_info exists gdb,nointerrupts]} {
     return
@@ -56,3 +57,16 @@ with_test_prefix "completion of layout names" {
 with_test_prefix "completion of focus command" {
     test_tab_completion "focus" "cmd *next *prev *src *"
 }
+
+# Now run some completion tests when TUI mode is enabled.
+Term::clean_restart 24 80
+if {![Term::prepare_for_tui]} {
+    unsupported "TUI not supported"
+    return
+}
+
+Term::command "layout src"
+Term::command "complete focus "
+Term::dump_screen
+Term::check_region_contents "check focus completions" 0 17 80 5 \
+    "focus cmd\\s*focus next\\s*focus prev\\s*focus src\\s*$gdb_prompt"
diff --git a/gdb/tui/tui-win.c b/gdb/tui/tui-win.c
index 4fc8e7a4503..492a5191025 100644
--- a/gdb/tui/tui-win.c
+++ b/gdb/tui/tui-win.c
@@ -362,13 +362,19 @@ show_tui_resize_message (struct ui_file *file, int from_tty,
 
 
 /* Generic window name completion function.  Complete window name pointed
-   to by TEXT and WORD.  If INCLUDE_NEXT_PREV_P is true then the special
-   window names 'next' and 'prev' will also be considered as possible
-   completions of the window name.  */
+   to by TEXT and WORD.
+
+   If EXCLUDE_CANNOT_FOCUS_P is true, then windows that can't take focus
+   will be excluded from the completions, otherwise they will be included.
+
+   If INCLUDE_NEXT_PREV_P is true then the special window names 'next' and
+   'prev' will also be considered as possible completions of the window
+   name.  This is independent of EXCLUDE_CANNOT_FOCUS_P.  */
 
 static void
 window_name_completer (completion_tracker &tracker,
-		       int include_next_prev_p,
+		       bool include_next_prev_p,
+		       bool exclude_cannot_focus_p,
 		       const char *text, const char *word)
 {
   std::vector<const char *> completion_name_vec;
@@ -377,10 +383,14 @@ window_name_completer (completion_tracker &tracker,
     {
       const char *completion_name = NULL;
 
-      /* We can't focus on an invisible window.  */
+      /* Don't include an invisible window.  */
       if (!win_info->is_visible ())
 	continue;
 
+      /* If requested, exclude windows that can't be focused.  */
+      if (exclude_cannot_focus_p && !win_info->can_focus ())
+	continue;
+
       completion_name = win_info->name ();
       gdb_assert (completion_name != NULL);
       completion_name_vec.push_back (completion_name);
@@ -415,7 +425,7 @@ focus_completer (struct cmd_list_element *ignore,
 		 completion_tracker &tracker,
 		 const char *text, const char *word)
 {
-  window_name_completer (tracker, 1, text, word);
+  window_name_completer (tracker, true, true, text, word);
 }
 
 /* Complete possible window names for winheight command.  TEXT is the
@@ -432,7 +442,7 @@ winheight_completer (struct cmd_list_element *ignore,
   if (word != text)
     return;
 
-  window_name_completer (tracker, 0, text, word);
+  window_name_completer (tracker, false, false, text, word);
 }
 
 /* Update gdb's knowledge of the terminal size.  */