[PATCHv2 07/15] gdb/tui: add left_boxed_p and right_boxed_p member functions

[Andrew Burgess <aburgess@redhat.com>]

When I initially saw this code in tui_layout_split::apply, I assumed
that this must be a bug:

    /* Two adjacent boxed windows will share a border, making a bit
       more size available.  */
    if (i > 0
        && m_splits[i - 1].layout->bottom_boxed_p ()
        && m_splits[i].layout->top_boxed_p ())
      ...

After all, the apply might be laying out a horizontal layout, right,
so checking bottom_boxed_p and top_boxed_p is clearly wrong.

Well, turns on, that due to the implementations of these things,
bottom_boxed_p is equivalent to an imagined right_boxed_p, and
top_boxed_p is equivalent to an imagined left_boxed_p.

I did consider just adding a comment about this to the above code, but
this still doesn't feel great.  So, in this commit, I've just filled
in the API to add right_boxed_p and left_boxed_p, and now I call these
instead of bottom_boxed_p and top_boxed_p if appropriate.

Maybe it's just pointless noise....

... I'd rather the main apply function not have to have special
knowledge about the implementation of these things coded into it.

There should be no user visible changes after this commit.
---
 gdb/tui/tui-layout.c | 46 ++++++++++++++++++++++++++++++++++++++++++--
 gdb/tui/tui-layout.h | 14 ++++++++++++++
 2 files changed, 58 insertions(+), 2 deletions(-)

diff --git a/gdb/tui/tui-layout.c b/gdb/tui/tui-layout.c
index 1ce912b3cdb..ca901e5c85d 100644
--- a/gdb/tui/tui-layout.c
+++ b/gdb/tui/tui-layout.c
@@ -468,6 +468,24 @@ tui_layout_window::bottom_boxed_p () const
 
 /* See tui-layout.h.  */
 
+bool
+tui_layout_window::left_boxed_p () const
+{
+  gdb_assert (m_window != nullptr);
+  return m_window->can_box ();
+}
+
+/* See tui-layout.h.  */
+
+bool
+tui_layout_window::right_boxed_p () const
+{
+  gdb_assert (m_window != nullptr);
+  return m_window->can_box ();
+}
+
+/* See tui-layout.h.  */
+
 void
 tui_layout_window::replace_window (const char *name, const char *new_window)
 {
@@ -580,6 +598,26 @@ tui_layout_split::bottom_boxed_p () const
 
 /* See tui-layout.h.  */
 
+bool
+tui_layout_split::left_boxed_p () const
+{
+  if (m_splits.empty ())
+    return false;
+  return m_splits[0].layout->left_boxed_p ();
+}
+
+/* See tui-layout.h.  */
+
+bool
+tui_layout_split::right_boxed_p () const
+{
+  if (m_splits.empty ())
+    return false;
+  return m_splits.back ().layout->right_boxed_p ();
+}
+
+/* See tui-layout.h.  */
+
 void
 tui_layout_split::set_weights_from_sizes ()
 {
@@ -777,8 +815,12 @@ tui_layout_split::apply (int x_, int y_, int width_, int height_)
       /* Two adjacent boxed windows will share a border, making a bit
 	 more size available.  */
       if (i > 0
-	  && m_splits[i - 1].layout->bottom_boxed_p ()
-	  && m_splits[i].layout->top_boxed_p ())
+	  && ((m_vertical
+	       && m_splits[i - 1].layout->bottom_boxed_p ()
+	       && m_splits[i].layout->top_boxed_p ())
+	      || (!m_vertical
+		  && m_splits[i - 1].layout->right_boxed_p ()
+		  && m_splits[i].layout->left_boxed_p ())))
 	info[i].share_box = true;
     }
 
diff --git a/gdb/tui/tui-layout.h b/gdb/tui/tui-layout.h
index ebfcae74356..e160eaa2256 100644
--- a/gdb/tui/tui-layout.h
+++ b/gdb/tui/tui-layout.h
@@ -68,6 +68,12 @@ class tui_layout_base
   /* True if the bottommost item in this layout is boxed.  */
   virtual bool bottom_boxed_p () const = 0;
 
+  /* True if the leftmost item in this layout is boxed.  */
+  virtual bool left_boxed_p () const = 0;
+
+  /* True if the rightmost item in this layout is boxed.  */
+  virtual bool right_boxed_p () const = 0;
+
   /* Return the name of this layout's window, or nullptr if this
      layout does not represent a single window.  */
   virtual const char *get_name () const
@@ -145,6 +151,10 @@ class tui_layout_window : public tui_layout_base
 
   bool bottom_boxed_p () const override;
 
+  bool left_boxed_p () const override;
+
+  bool right_boxed_p () const override;
+
   void remove_windows (const char *name) override
   {
   }
@@ -215,6 +225,10 @@ class tui_layout_split : public tui_layout_base
 
   bool bottom_boxed_p () const override;
 
+  bool left_boxed_p () const override;
+
+  bool right_boxed_p () const override;
+
   void remove_windows (const char *name) override;
 
   void replace_window (const char *name, const char *new_window) override;
-- 
2.25.4