[PATCH] Add tab completion for TUI's "focus" command

[Patrick Palka <patrick@parcs.ath.cx>]

The implementation is pretty straightforward, though there's the
question of what the completion list should show when the TUI has not
yet been initalized.  At that point no TUI window is considered visible
thus the completion list will be composed of only the "next" and "prev"
keywords (which are always added to the completion list).  But
technically the commands "focus cmd" and "focus src" will work even when
the TUI is not yet initialized because the initialization done in the
meantime will make these windows visible by default.  So should the
entries "cmd" and "src" be added to the completion list as special
cases when the TUI is not yet initialized?

gdb/ChangeLog:

	* tui/tui-win.c (focus_completer): New static function.
	(_initialize_tui_win): Set the completion function of the
	"focus" command to focus_completer.

gdb/testsuite/ChangeLog:

	* gdb.base/completion.exp: Test the completion of the "focus"
	command.
---
 gdb/testsuite/gdb.base/completion.exp | 18 +++++++++++
 gdb/tui/tui-win.c                     | 59 ++++++++++++++++++++++++++++++++++-
 2 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/gdb/testsuite/gdb.base/completion.exp b/gdb/testsuite/gdb.base/completion.exp
index 4c31bfc..5c20f26 100644
--- a/gdb/testsuite/gdb.base/completion.exp
+++ b/gdb/testsuite/gdb.base/completion.exp
@@ -878,3 +878,21 @@ if {![skip_tui_tests]} {
 	}
     }
 }
+if {![skip_tui_tests]} {
+    with_test_prefix "focus command" {
+	set test "test completion"
+	send_gdb "focus\t\t\t"
+	gdb_test_multiple "" "$test" {
+	    -re "next *prev *\r\n$gdb_prompt focus $" {
+		pass "$test"
+	    }
+	}
+	send_gdb "\003"
+	set test "quit command input after testing completion"
+	gdb_test_multiple "" "$test" {
+	    -re "$gdb_prompt $" {
+		pass "$test"
+	    }
+	}
+    }
+}
diff --git a/gdb/tui/tui-win.c b/gdb/tui/tui-win.c
index 8c0685b..8860ca7 100644
--- a/gdb/tui/tui-win.c
+++ b/gdb/tui/tui-win.c
@@ -354,6 +354,61 @@ tui_set_var_cmd (char *null_args, int from_tty, struct cmd_list_element *c)
     tui_rehighlight_all ();
 }
 
+/* Complete possible window names to focus on.  TEXT is the complete text
+   entered so far, WORD is the word currently being completed.  */
+
+static VEC (char_ptr) *
+focus_completer (struct cmd_list_element *ignore,
+		  const char *text, const char *word)
+{
+  VEC (const_char_ptr) *completion_name_vec = NULL;
+  VEC (char_ptr) *matches_vec;
+  int win_type;
+
+  for (win_type = SRC_WIN; win_type < MAX_MAJOR_WINDOWS; win_type++)
+    {
+      const char *completion_name = NULL;
+
+      /* We can't focus on an invisible window.  */
+      if (tui_win_list[win_type] == NULL
+	  || !tui_win_list[win_type]->generic.is_visible)
+	continue;
+
+      switch (win_type)
+	{
+	case SRC_WIN:
+	  completion_name = "src";
+	  break;
+	case DISASSEM_WIN:
+	  completion_name = "asm";
+	  break;
+	case DATA_WIN:
+	  completion_name = "regs";
+	  break;
+	case CMD_WIN:
+	  completion_name = "cmd";
+	  break;
+	default:
+	  break;
+	}
+
+      if (completion_name != NULL)
+	VEC_safe_push (const_char_ptr, completion_name_vec, completion_name);
+    }
+
+  VEC_safe_push (const_char_ptr, completion_name_vec, "next");
+  VEC_safe_push (const_char_ptr, completion_name_vec, "prev");
+  VEC_safe_push (const_char_ptr, completion_name_vec, NULL);
+
+  matches_vec
+    = complete_on_enum (VEC_address (const_char_ptr, completion_name_vec),
+			text, word);
+
+  VEC_free (const_char_ptr, completion_name_vec);
+
+  return matches_vec;
+}
+
 /* Function to initialize gdb commands, for tui window
    manipulation.  */
 
@@ -365,6 +420,7 @@ _initialize_tui_win (void)
 {
   static struct cmd_list_element *tui_setlist;
   static struct cmd_list_element *tui_showlist;
+  struct cmd_list_element *focus_cmd;
 
   /* Define the classes of commands.
      They will appear in the help list in the reverse of this order.  */
@@ -393,7 +449,7 @@ regs : the register display\n"));
   add_com_alias ("wh", "winheight", class_tui, 0);
   add_info ("win", tui_all_windows_info,
 	    _("List of all displayed windows.\n"));
-  add_com ("focus", class_tui, tui_set_focus_command, _("\
+  focus_cmd = add_com ("focus", class_tui, tui_set_focus_command, _("\
 Set focus to named window or next/prev window.\n\
 Usage: focus {<win> | next | prev}\n\
 Valid Window names are:\n\
@@ -402,6 +458,7 @@ asm  : the disassembly window\n\
 regs : the register display\n\
 cmd  : the command window\n"));
   add_com_alias ("fs", "focus", class_tui, 0);
+  set_cmd_completer (focus_cmd, focus_completer);
   add_com ("+", class_tui, tui_scroll_forward_command, _("\
 Scroll window forward.\n\
 Usage: + [win] [n]\n"));
-- 
2.4.4.410.g43ed522.dirty