Re: [PATCHv2 05/15] gdb/tui: add new 'tui window width' command and 'winwidth' alias

[Andrew Burgess <aburgess@redhat.com>]

Eli Zaretskii via Gdb-patches <gdb-patches@sourceware.org> writes:

>> Date: Sun,  6 Feb 2022 14:12:43 +0000
>> From: Andrew Burgess via Gdb-patches <gdb-patches@sourceware.org>
>> Cc: Andrew Burgess <aburgess@redhat.com>
>> 
>>  gdb/NEWS                           |   6 ++
>>  gdb/doc/gdb.texinfo                |  12 ++++
>>  gdb/testsuite/gdb.tui/winwidth.exp |  62 +++++++++++++++++
>>  gdb/tui/tui-layout.c               |  23 +++++--
>>  gdb/tui/tui-layout.h               | 104 ++++++++++++++++++++++++++++-
>>  gdb/tui/tui-win.c                  |  99 +++++++++++++++++++++++++--
>>  6 files changed, 291 insertions(+), 15 deletions(-)
>>  create mode 100644 gdb/testsuite/gdb.tui/winwidth.exp
>
> OK for the documentation parts.
>
> Btw, should we mention that this new command will only have effect if
> more than one window is displayed?

What about this for the description of 'tui window width'?  The second
paragraph is new:

  @kindex tui window width
  @kindex winwidth
  @item tui window width @var{name} +@var{count}
  @itemx tui window width @var{name} -@var{count}
  @itemx winwidth @var{name} +@var{count}
  @itemx winwidth @var{name} -@var{count}
  Change the width of the window @var{name} by @var{count} columns.
  Positive counts increase the width, while negative counts decrease it.
  The @var{name} parameter can be the name of any currently visible
  window.  The names of the currently visible windows can be discovered
  using @code{info win} (@pxref{info_win_command,,info win}).
  
  The set of currently visible windows must always fill the terminal,
  and so, it is only possible to resize on window if there are other
  visible windows that can either give or receive the extra terminal
  space.

If this is OK, then I would propose adding the same paragraph to the
description of 'tui window height' which obviously has the same
restrictions.

The complete patch, including the new paragraphs is included below.

Thanks,
Andrew

---

commit 3fd38b7966faa8371f91c70c4e4914b6c786b6ef
Author: Andrew Burgess <aburgess@redhat.com>
Date:   Mon Jan 24 22:02:59 2022 +0000

    gdb/tui: add new 'tui window width' command and 'winwidth' alias
    
    This commit adds a new command 'tui window width', and an alias
    'winwidth'.  This command is equivalent to the old 'winheight'
    command (which was recently renamed 'tui window height').
    
    Even though I recently moved the old tui commands under the tui
    namespace, and I would strongly encourage all new tui commands to be
    added as 'tui ....' only (users can create their own top-level aliases
    if they want), I'm breaking that suggestion here, and adding a
    'winwidth' alias.
    
    Given that we already have 'winheight' and have done for years, it
    just didn't seem right to no have the matching 'winwidth'.
    
    You might notice in the test that the window resizing doesn't quite
    work right.  I setup a horizontal layout, then grow and shrink the
    windows.  At the end of the test the windows should be back to their
    original size...
    
    ... they are not.  This isn't my fault, honest!  GDB's window resizing
    is a little ... temperamental, and is prone to getting things slightly
    wrong during resizes, off by 1 type things.  This is true for height
    resizing, as well as the new width resizing.
    
    Later patches in this series will rework the resizing algorithm, which
    should improve things in this area.  For now, I'm happy that the width
    resizing is as good as the height resizing, given the existing quirks.
    
    For the docs side I include a paragraph that explains how multiple
    windows are required before the width can be adjusted.  For
    completeness, I've added the same paragraph to the winheight
    description.  With the predefined layouts this extra paragraph is not
    really needed for winheight, as there are always multiple windows on
    the screen.  However, with custom layouts, this might not be true, so
    adding the paragraph seems like a good idea.
    
    As for the changes in gdb itself, I've mostly just templated the
    existing height adjustment code so that the two functions
    tui_layout_split::adjust_size (tui-layout.c) and
    tui_set_win_height_command (tui-win.c) now have a template parameter
    "policy", this policy allows me to specialise the functions for either
    width or height adjustment.  Function arguments, and locals, are
    renamed, replacing 'height' with 'size'.

diff --git a/gdb/NEWS b/gdb/NEWS
index b06eb473ffb..3a05b95a3d9 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -97,6 +97,12 @@ tui window height
   and 'winheight' tui commands respectively.  The old names still
   exist as aliases to these new commands.
 
+tui window width
+winwidth
+  The new command 'tui window width', and the alias 'winwidth' allow
+  the width of a tui window to be adjusted when windows are laid out
+  in horizontal mode.
+
 * Changed commands
 
 maint packet
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 6ddcc099cd8..e144255df69 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -29044,6 +29044,28 @@
 it.  The @var{name} parameter can be the name of any currently visible
 window.  The names of the currently visible windows can be discovered
 using @kbd{info win} (@pxref{info_win_command,,info win}).
+
+The set of currently visible windows must always fill the terminal,
+and so, it is only possible to resize on window if there are other
+visible windows that can either give or receive the extra terminal
+space.
+
+@kindex tui window width
+@kindex winwidth
+@item tui window width @var{name} +@var{count}
+@itemx tui window width @var{name} -@var{count}
+@itemx winwidth @var{name} +@var{count}
+@itemx winwidth @var{name} -@var{count}
+Change the width of the window @var{name} by @var{count} columns.
+Positive counts increase the width, while negative counts decrease it.
+The @var{name} parameter can be the name of any currently visible
+window.  The names of the currently visible windows can be discovered
+using @code{info win} (@pxref{info_win_command,,info win}).
+
+The set of currently visible windows must always fill the terminal,
+and so, it is only possible to resize on window if there are other
+visible windows that can either give or receive the extra terminal
+space.
 @end table
 
 @node TUI Configuration
diff --git a/gdb/testsuite/gdb.tui/winwidth.exp b/gdb/testsuite/gdb.tui/winwidth.exp
new file mode 100644
index 00000000000..b0a838b578f
--- /dev/null
+++ b/gdb/testsuite/gdb.tui/winwidth.exp
@@ -0,0 +1,62 @@
+# Copyright 2022 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 the "winwidth" command.
+
+tuiterm_env
+
+standard_testfile tui-layout.c
+
+if {[build_executable "failed to prepare" ${testfile} ${srcfile}] == -1} {
+    return -1
+}
+
+Term::clean_restart 24 80 $testfile
+if {![Term::enter_tui]} {
+    unsupported "TUI not supported"
+    return
+}
+
+Term::command "tui new-layout h { -horizontal src 1 asm 1 } 1 status 0 cmd 1"
+Term::command "layout h"
+
+with_test_prefix "original window sizes" {
+    Term::check_box "source box" 0 0 40 15
+    Term::check_box "asm box" 39 0 41 15
+    Term::command "winwidth src +5"
+}
+
+with_test_prefix "after src +5" {
+    Term::check_box "source box" 0 0 44 15
+    Term::check_box "asm box" 43 0 37 15
+    Term::command "winwidth asm -5"
+}
+
+with_test_prefix "after asm -5" {
+    Term::check_box "source box" 0 0 48 15
+    Term::check_box "asm box" 47 0 33 15
+    Term::command "winwidth asm +8"
+}
+
+with_test_prefix "after asm +8" {
+    Term::check_box "source box" 0 0 39 15
+    Term::check_box "asm box" 38 0 42 15
+    Term::command "winwidth src -2"
+}
+
+with_test_prefix "after src -2" {
+    Term::check_box "source box" 0 0 36 15
+    Term::check_box "asm box" 35 0 45 15
+}
diff --git a/gdb/tui/tui-layout.c b/gdb/tui/tui-layout.c
index 9e856ccf3fa..13e4d462426 100644
--- a/gdb/tui/tui-layout.c
+++ b/gdb/tui/tui-layout.c
@@ -121,6 +121,14 @@ tui_adjust_window_height (struct tui_win_info *win, int new_height)
   applied_layout->set_height (win->name (), new_height);
 }
 
+/* See tui-layout.  */
+
+void
+tui_adjust_window_width (struct tui_win_info *win, int new_width)
+{
+  applied_layout->set_width (win->name (), new_width);
+}
+
 /* Set the current layout to LAYOUT.  */
 
 static void
@@ -570,8 +578,9 @@ tui_layout_split::set_weights_from_sizes ()
 
 /* See tui-layout.h.  */
 
+template<class Policy>
 tui_adjust_result
-tui_layout_split::set_height (const char *name, int new_height)
+tui_layout_split::set_size (const char *name, int new_size)
 {
   /* Look through the children.  If one is a layout holding the named
      window, we're done; or if one actually is the named window,
@@ -580,12 +589,12 @@ tui_layout_split::set_height (const char *name, int new_height)
   for (int i = 0; i < m_splits.size (); ++i)
     {
       tui_adjust_result adjusted
-	= m_splits[i].layout->set_height (name, new_height);
+	= Policy::set_size (m_splits[i].layout, name, new_size);
       if (adjusted == HANDLED)
 	return HANDLED;
       if (adjusted == FOUND)
 	{
-	  if (!m_vertical)
+	  if (!Policy::can_adjust (this))
 	    return FOUND;
 	  found_index = i;
 	  break;
@@ -594,12 +603,12 @@ tui_layout_split::set_height (const char *name, int new_height)
 
   if (found_index == -1)
     return NOT_FOUND;
-  if (m_splits[found_index].layout->height == new_height)
+  if (Policy::current_size (m_splits[found_index].layout) == new_size)
     return HANDLED;
 
   set_weights_from_sizes ();
-  int delta = m_splits[found_index].weight - new_height;
-  m_splits[found_index].weight = new_height;
+  int delta = m_splits[found_index].weight - new_size;
+  m_splits[found_index].weight = new_size;
 
   /* Distribute the "delta" over the next window; but if the next
      window cannot hold it all, keep going until we either find a
@@ -633,7 +642,7 @@ tui_layout_split::set_height (const char *name, int new_height)
 
   if (delta != 0)
     {
-      warning (_("Invalid window height specified"));
+      Policy::invalid_size_warning ();
       /* Effectively undo any modifications made here.  */
       set_weights_from_sizes ();
     }
diff --git a/gdb/tui/tui-layout.h b/gdb/tui/tui-layout.h
index 8f41835b94c..f4ef0895f1f 100644
--- a/gdb/tui/tui-layout.h
+++ b/gdb/tui/tui-layout.h
@@ -79,6 +79,10 @@ class tui_layout_base
      the sizes of the other windows around it.  */
   virtual tui_adjust_result set_height (const char *name, int new_height) = 0;
 
+  /* Set the width of the window named NAME to NEW_WIDTH, updating
+     the sizes of the other windows around it.  */
+  virtual tui_adjust_result set_width (const char *name, int new_width) = 0;
+
   /* Remove some windows from the layout, leaving the command window
      and the window being passed in here.  */
   virtual void remove_windows (const char *name) = 0;
@@ -132,6 +136,11 @@ class tui_layout_window : public tui_layout_base
     return m_contents == name ? FOUND : NOT_FOUND;
   }
 
+  tui_adjust_result set_width (const char *name, int new_width) override
+  {
+    return m_contents == name ? FOUND : NOT_FOUND;
+  }
+
   bool top_boxed_p () const override;
 
   bool bottom_boxed_p () const override;
@@ -192,7 +201,15 @@ class tui_layout_split : public tui_layout_base
 
   void apply (int x, int y, int width, int height) override;
 
-  tui_adjust_result set_height (const char *name, int new_height) override;
+  tui_adjust_result set_height (const char *name, int new_height) override
+  {
+    return set_size<tui_layout_split::set_height_policy> (name, new_height);
+  }
+
+  tui_adjust_result set_width (const char *name, int new_width) override
+  {
+    return set_size<tui_layout_split::set_width_policy> (name, new_width);
+  }
 
   bool top_boxed_p () const override;
 
@@ -217,6 +234,87 @@ class tui_layout_split : public tui_layout_base
 
 private:
 
+  /* Used to implement set_height and set_width member functions.  Set
+     either the height or width of the window named NAME to NEW_SIZE,
+     updating the sizes of the other windows around it as needed.  The
+     POLICY is used to specialize this function to adjust either the height
+     or the width.  */
+
+  template <class Policy>
+  tui_adjust_result set_size (const char *name, int new_size);
+
+  /* A policy class for use with the set_size member function, use when we
+     want to adjust the height of a named window.  */
+
+  struct set_height_policy
+  {
+    /* Set the height of window named NAME to NEW_HEIGHT in LAYOUT.  */
+    static tui_adjust_result
+    set_size (std::unique_ptr<tui_layout_base> &layout,
+	      const char *name,
+	      int new_height)
+    {
+      return layout->set_height (name, new_height);
+    }
+
+    /* Can we adjust the heights of windows in SPLIT?  */
+    static bool
+    can_adjust (const tui_layout_split *split)
+    {
+      return split->m_vertical;
+    }
+
+    /* What is the current height of LAYOUT.  */
+    static int
+    current_size (std::unique_ptr<tui_layout_base> &layout)
+    {
+      return layout->height;
+    }
+
+    /* Warn about invalid height specification.  */
+    static void
+    invalid_size_warning ()
+    {
+      warning (_("Invalid window height specified"));
+    }
+  };
+
+  /* A policy class for use with the set_size member function, use when we
+     want to adjust the width of a named window.  */
+
+  struct set_width_policy
+  {
+    /* Set the width of window named NAME to NEW_HEIGHT in LAYOUT.  */
+    static tui_adjust_result
+    set_size (std::unique_ptr<tui_layout_base> &layout,
+	      const char *name,
+	      int new_width)
+    {
+      return layout->set_width (name, new_width);
+    }
+
+    /* Can we adjust the widths of windows in SPLIT?  */
+    static bool
+    can_adjust (const tui_layout_split *split)
+    {
+      return !split->m_vertical;
+    }
+
+    /* What is the current width of LAYOUT.  */
+    static int
+    current_size (std::unique_ptr<tui_layout_base> &layout)
+    {
+      return layout->width;
+    }
+
+    /* Warn about invalid height specification.  */
+    static void
+    invalid_size_warning ()
+    {
+      warning (_("Invalid window width specified"));
+    }
+  };
+
   /* Set the weights from the current heights (when m_vertical is true) or
      widths (when m_vertical is false).  */
   void set_weights_from_sizes ();
@@ -266,6 +364,10 @@ extern void tui_apply_current_layout ();
 extern void tui_adjust_window_height (struct tui_win_info *win,
 				      int new_height);
 
+/* Adjust the window width of WIN to NEW_WIDTH.  */
+extern void tui_adjust_window_width (struct tui_win_info *win,
+				     int new_width);
+
 /* The type of a function that is used to create a TUI window.  */
 
 typedef std::function<tui_win_info * (const char *name)> window_factory;
diff --git a/gdb/tui/tui-win.c b/gdb/tui/tui-win.c
index ba6aca3d078..953af640c93 100644
--- a/gdb/tui/tui-win.c
+++ b/gdb/tui/tui-win.c
@@ -842,10 +842,21 @@ tui_set_tab_width_command (const char *arg, int from_tty)
     }
 }
 
+/* Helper function for the user commands to adjust a window's width or
+   height.  The ARG string contains the command line arguments from the
+   user, which should give the name of a window, and how to adjust the
+   size.
 
-/* Set the height of the specified window.  */
+   The Policy type is used to specialise this function for updating either
+   the width or height of the window.
+
+   On invalid input, or if the size can't be adjusted as requested, then an
+   error is thrown, otherwise, the window sizes are adjusted, and the
+   windows redrawn.  */
+
+template<typename Policy>
 static void
-tui_set_win_height_command (const char *arg, int from_tty)
+tui_set_win_size (const char *arg)
 {
   /* Make sure the curses mode is enabled.  */
   tui_enable ();
@@ -854,7 +865,7 @@ tui_set_win_height_command (const char *arg, int from_tty)
 
   const char *buf = arg;
   const char *buf_ptr = buf;
-  int new_height;
+  int new_size;
   struct tui_win_info *win_info;
 
   buf_ptr = skip_to_space (buf_ptr);
@@ -890,18 +901,82 @@ tui_set_win_height_command (const char *arg, int from_tty)
 	  if (negate)
 	    input_no *= (-1);
 	  if (fixed_size)
-	    new_height = input_no;
+	    new_size = input_no;
 	  else
-	    new_height = win_info->height + input_no;
+	    new_size = Policy::existing_window_size (win_info) + input_no;
 
 	  /* Now change the window's height, and adjust
 	     all other windows around it.  */
-	  tui_adjust_window_height (win_info, new_height);
+	  Policy::adjust_window_size (win_info, new_size);
 	  tui_update_gdb_sizes ();
 	}
       else
-	error (_("Invalid window height specified"));
+	Policy::invalid_size_error ();
+    }
+}
+
+/* Implement the 'tui window height' command (alias 'winheight').  */
+
+static void
+tui_set_win_height_command (const char *arg, int from_tty)
+{
+  /* Policy class for use with tui_set_win_size, this policy adjusts the
+     height of a window.  */
+  struct height_adjustment_policy
+  {
+    /* Called when the size specified is invalid.  */
+    static void invalid_size_error ()
+    {
+      error (_("Invalid window height specified"));
+    }
+
+    /* Return the existing size, height in this case, of a window WIN_INFO.  */
+    static int existing_window_size (struct tui_win_info *win_info)
+    {
+      return win_info->height;
+    }
+
+    /* Set the size, height in this case, of WIN_INFO to NEW_SIZE.  */
+    static void adjust_window_size (struct tui_win_info *win_info,
+				    int new_size)
+    {
+      tui_adjust_window_height (win_info, new_size);
+    }
+  };
+
+  tui_set_win_size<height_adjustment_policy> (arg);
+}
+
+/* Implement the 'tui window width' command (alias 'winwidth').  */
+
+static void
+tui_set_win_width_command (const char *arg, int from_tty)
+{
+  /* Policy class for use with tui_set_win_size, this policy adjusts the
+     width of a window.  */
+  struct width_adjustment_policy
+  {
+    /* Called when the size specified is invalid.  */
+    static void invalid_size_error ()
+    {
+      error (_("Invalid window width specified"));
     }
+
+    /* Return the existing size, width in this case, of a window WIN_INFO.  */
+    static int existing_window_size (struct tui_win_info *win_info)
+    {
+      return win_info->width;
+    }
+
+    /* Set the size, width in this case, of WIN_INFO to NEW_SIZE.  */
+    static void adjust_window_size (struct tui_win_info *win_info,
+				    int new_size)
+    {
+      tui_adjust_window_width (win_info, new_size);
+    }
+  };
+
+  tui_set_win_size<width_adjustment_policy> (arg);
 }
 
 /* See tui-data.h.  */
@@ -1033,6 +1108,16 @@ Use \"info win\" to see the names of the windows currently being displayed."),
   add_com_alias ("winheight", winheight_cmd, class_tui, 0);
   add_com_alias ("wh", winheight_cmd, class_tui, 0);
   set_cmd_completer (winheight_cmd, winheight_completer);
+
+  cmd_list_element *winwidth_cmd
+    = add_cmd ("width", class_tui, tui_set_win_width_command, _("\
+Set or modify the width of a specified window.\n\
+Usage: tui window width WINDOW-NAME [+ | -] NUM-LINES\n\
+Use \"info win\" to see the names of the windows currently being displayed."),
+	       &tui_window_cmds);
+  add_com_alias ("winwidth", winwidth_cmd, class_tui, 0);
+  set_cmd_completer (winwidth_cmd, winheight_completer);
+
   add_info ("win", tui_all_windows_info,
 	    _("List of all displayed windows.\n\
 Usage: info win"));