[PATCH] Don't let TUI focus on locator

[Tom Tromey]

>> Let me know what you think of this.

Simon> That looks good to me, thanks!

Simon> I've never looked at the TUI tests but... how hard would it be to write
Simon> a test for this?

I skipped it since I thought it would be hard, but I forgot that "focus"
tells us what it is doing, and so it turned out to be super easy :}

Tom

commit b551a89f51504735e9979ac885a5784e21cfecef
Author: Tom Tromey <tromey@adacore.com>
Date:   Wed Sep 23 12:57:19 2020 -0600

    Don't let TUI focus on locator
    
    PR tui/26638 notes that the C-x o binding can put the focus on the
    locator window.  However, this is not useful and did not happen
    historically.  This patch changes the TUI to skip this window when
    switching focus.
    
    gdb/ChangeLog
    2020-09-24  Tom Tromey  <tromey@adacore.com>
    
            PR tui/26638:
            * tui/tui-stack.h (struct tui_locator_window) <can_focus>: New
            method.
            * tui/tui-data.h (struct tui_win_info) <can_focus>: New method.
            * tui/tui-data.c (tui_next_win): Exclude non-focusable windows.
            (tui_prev_win): Rewrite.
    
    gdb/testsuite/ChangeLog
    2020-09-24  Tom Tromey  <tromey@adacore.com>
    
            PR tui/26638:
            * gdb.tui/list.exp: Check output of "focus next".

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 3b851dba41e..3872a8d9cbe 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,12 @@
+2020-09-24  Tom Tromey  <tromey@adacore.com>
+
+	PR tui/26638:
+	* tui/tui-stack.h (struct tui_locator_window) <can_focus>: New
+	method.
+	* tui/tui-data.h (struct tui_win_info) <can_focus>: New method.
+	* tui/tui-data.c (tui_next_win): Exclude non-focusable windows.
+	(tui_prev_win): Rewrite.
+
 2020-09-23  Hannes Domani  <ssbssa@yahoo.de>
 
 	* nat/windows-nat.c (handle_exception): Handle 64bit breakpoints
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index c85f3ed9427..41849756f97 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-09-24  Tom Tromey  <tromey@adacore.com>
+
+	PR tui/26638:
+	* gdb.tui/list.exp: Check output of "focus next".
+
 2020-09-23  Tom Tromey  <tom@tromey.com>
 
 	* gdb.dwarf2/intbits.exp: New file.
diff --git a/gdb/testsuite/gdb.tui/list.exp b/gdb/testsuite/gdb.tui/list.exp
index 77dbd69efd8..576b33fa869 100644
--- a/gdb/testsuite/gdb.tui/list.exp
+++ b/gdb/testsuite/gdb.tui/list.exp
@@ -39,3 +39,4 @@ Term::check_contents "list main" "21 *return 0"
 # The following 'focus next' must be immediately after 'list main' to
 # ensure that GDB has a valid idea of what is currently focused.
 Term::command "focus next"
+Term::check_contents "focus next" "Focus set to cmd window"
diff --git a/gdb/tui/tui-data.c b/gdb/tui/tui-data.c
index 8f7d257e945..d475d031065 100644
--- a/gdb/tui/tui-data.c
+++ b/gdb/tui/tui-data.c
@@ -113,9 +113,18 @@ tui_next_win (struct tui_win_info *cur_win)
   auto iter = std::find (tui_windows.begin (), tui_windows.end (), cur_win);
   gdb_assert (iter != tui_windows.end ());
 
-  ++iter;
-  if (iter == tui_windows.end ())
-    return tui_windows[0];
+  gdb_assert (cur_win->can_focus ());
+  /* This won't loop forever since we can't have just an un-focusable
+     window.  */
+  while (true)
+    {
+      ++iter;
+      if (iter == tui_windows.end ())
+	iter = tui_windows.begin ();
+      if ((*iter)->can_focus ())
+	break;
+    }
+
   return *iter;
 }
 
@@ -125,12 +134,21 @@ tui_next_win (struct tui_win_info *cur_win)
 struct tui_win_info *
 tui_prev_win (struct tui_win_info *cur_win)
 {
-  auto iter = std::find (tui_windows.begin (), tui_windows.end (), cur_win);
-  gdb_assert (iter != tui_windows.end ());
+  auto iter = std::find (tui_windows.rbegin (), tui_windows.rend (), cur_win);
+  gdb_assert (iter != tui_windows.rend ());
+
+  gdb_assert (cur_win->can_focus ());
+  /* This won't loop forever since we can't have just an un-focusable
+     window.  */
+  while (true)
+    {
+      ++iter;
+      if (iter == tui_windows.rend ())
+	iter = tui_windows.rbegin ();
+      if ((*iter)->can_focus ())
+	break;
+    }
 
-  if (iter == tui_windows.begin ())
-    return tui_windows.back ();
-  --iter;
   return *iter;
 }
 
diff --git a/gdb/tui/tui-data.h b/gdb/tui/tui-data.h
index 5e7a12293c9..d61bfc7dff8 100644
--- a/gdb/tui/tui-data.h
+++ b/gdb/tui/tui-data.h
@@ -99,6 +99,12 @@ struct tui_win_info
     return handle != nullptr;
   }
 
+  /* Return true if this window can accept the focus.  */
+  virtual bool can_focus () const
+  {
+    return true;
+  }
+
   /* Disable output until the next call to doupdate.  */
   void no_refresh ()
   {
diff --git a/gdb/tui/tui-stack.h b/gdb/tui/tui-stack.h
index 9ff57b1ba73..0e5916f0ce3 100644
--- a/gdb/tui/tui-stack.h
+++ b/gdb/tui/tui-stack.h
@@ -52,6 +52,11 @@ struct tui_locator_window : public tui_win_info
     return false;
   }
 
+  bool can_focus () const override
+  {
+    return false;
+  }
+
   void rerender () override;
 
   /* Update the locator, with the provided arguments.