[elbe-devel] [PATCH 01/14] Debianize - TUI

[dion at linutronix.de]

From: Olivier Dion <dion at linutronix.de>

The TUI uses the Urwid package, see <http://urwid.org/>.

The code is copy-paste from one of my previous collaborate project
with a friend at <https://github.com/abelfodil/inf1900-grader> and is
under GPL-3.

I've also made some modifications to fits the debianizer needs.

* TUI

  The TUI is a singleton object that control the terminal.  It divides
  it in 3 sections.  The header, the body and the footer.  Is also
  install signal handler to ensure proper restoration of the terminal
  settings.

** Header

   The header is a Text widget.  It's manipulated through the
   TUI.print and TUI.clear method.

*** TUI.print

    Print a formatted text to the header.  The previous text is
    overwritten.

*** TUI.clear

    Clear the header.

** Footer

   The footer is a Text widget.  It's not intend to be manipulated.
   It only show usefull keybinding to the user.

** Body

   The body can be anything.  It's the main view of the application.

Signed-off-by: Olivier Dion <dion at linutronix.de>
---
 elbepack/debianize/base/tui.py | 181 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 181 insertions(+)
 create mode 100644 elbepack/debianize/base/tui.py

diff --git a/elbepack/debianize/base/tui.py b/elbepack/debianize/base/tui.py
new file mode 100644
index 00000000..1b4cdeec
--- /dev/null
+++ b/elbepack/debianize/base/tui.py
@@ -0,0 +1,181 @@
+# ELBE - Debian Based Embedded Rootfilesystem Builder
+# Copyright (c) 2019 Olivier Dion <dion at linutronix.de>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+
+import os
+import signal
+
+from urwid import (
+    ExitMainLoop,
+    Frame,
+    MainLoop,
+    Text
+)
+
+
+# +=====================================================+
+# |+-: root (box) -------------------------------------+|
+# ||+-: header (flow) --------------------------------+||
+# |||                                                 |||
+# ||+-------------------------------------------------+||
+# ||+-: body (box) -----------------------------------+||
+# |||                                                 |||
+# |||                                                 |||
+# |||                                                 |||
+# |||                                                 |||
+# |||                                                 |||
+# |||                                                 |||
+# |||                                                 |||
+# |||                                                 |||
+# |||                                                 |||
+# |||                                                 |||
+# ||+-------------------------------------------------+||
+# ||+-: helper (flow) --------------------------------+||
+# |||                                                 | |
+# ||+-------------------------------------------------+||
+# |+---------------------------------------------------+|
+# +=====================================================+
+
+
+def generate_helper_text(hints):
+    markup = []
+    for key, text, text_palette in hints:
+        markup.extend((("helper_key", key), " ", (text_palette, text), " "))
+    return markup
+
+
+class TUIException(Exception):
+    pass
+
+
+class TUI(object):
+
+    palette = [
+        ("blue_head", "dark blue", ""),
+        ("red_head", "dark red", ""),
+        ("header", "bold, underline, default", ""),
+        ("error", "bold, light red", ""),
+        ("normal_box", "default", "default"),
+        ("selected_box", "black", "light gray"),
+        ("confirm_button", "default", "dark green"),
+        ("abort_button", "light red", "dark red"),
+        ("progress_low", "default", "yellow"),
+        ("progress_hight", "default", "dark green"),
+        ("helper_key", "bold", "default"),
+        ("helper_text_brown", "black", "brown"),
+        ("helper_text_red", "black", "dark red"),
+        ("helper_text_green", "black", "dark green"),
+        ("helper_text_light", "white", "dark blue"),
+    ]
+
+    main_helper_text = generate_helper_text([
+        ("C-f", "Forward", "helper_text_brown"),
+        ("C-b", "Backward", "helper_text_brown"),
+        ("C-p", "Previous", "helper_text_brown"),
+        ("C-n", "Next", "helper_text_brown"),
+        ("TAB", "Next", "helper_text_brown"),
+        ("backtab", "Previous", "helper_text_brown"),
+        ("C-\\", "Quit", "helper_text_red"),
+    ])
+
+    keybind = {}
+
+    def __init__(self, body):
+
+        TUI.root = Frame(body.root,
+                         Text(("header", ""), "center"),
+                         Text(TUI.main_helper_text, "center"))
+
+        TUI.loop = MainLoop(TUI.root, TUI.palette,
+                            unhandled_input=TUI.unhandled_input)
+
+        TUI.install_signals_handler()
+
+    def __call__(self):
+        TUI.loop.run()
+
+    @classmethod
+    def focus_header(cls):
+        cls.root.focus_position = "header"
+
+    @classmethod
+    def focus_body(cls):
+        cls.root.focus_position = "body"
+
+    @classmethod
+    def focus_footer(cls):
+        cls.root.focus_position = "footer"
+
+    @classmethod
+    def header(cls, flow_widget=None):
+        if flow_widget is not None:
+            if "flow" not in flow_widget.sizing():
+                raise TUIException("Header must be of sizing flow")
+            cls.root.contents["header"] = flow_widget
+        return cls.root.contents["header"]
+
+    @classmethod
+    def body(cls, box_widget=None):
+        if box_widget is not None:
+            if "box" not in box_widget.sizing():
+                raise TUIException("Body must be of sizing box")
+            cls.root.contents["body"] = (box_widget, TUI.root.options())
+        return cls.root.contents["body"]
+
+    @classmethod
+    def footer(cls, flow_widget=None):
+        if flow_widget is not None:
+            if "flow" not in flow_widget.sizing():
+                raise TUIException("Header must be of sizing flow")
+            cls.root.contents["footer"] = flow_widget
+        return cls.root.contents["footer"]
+
+    @classmethod
+    def unhandled_input(cls, key):
+        if key in cls.keybind:
+            cls.keybind[key]()
+            return None
+
+    @classmethod
+    def bind_global(cls, key, callback):
+        cls.keybind[key] = callback
+
+    @classmethod
+    def printf(cls, fmt, *args):
+        cls.header()[0].set_text(("header", fmt.format(*args)))
+
+    @classmethod
+    def clear(cls):
+        cls.printf("")
+
+    @staticmethod
+    def quit(*kargs):
+        raise ExitMainLoop()
+
+    @staticmethod
+    def pause(*kargs):
+        TUI.loop.stop()
+        os.kill(os.getpid(), signal.SIGSTOP)
+        TUI.loop.start()
+        TUI.loop.draw_screen()
+
+    @staticmethod
+    def interrupt(*kargs):
+        pass
+
+    @staticmethod
+    def install_signals_handler():
+
+        if os.sys.platform != "win32":
+            signal.signal(signal.SIGQUIT, TUI.quit)
+            signal.signal(signal.SIGTSTP, TUI.pause)
+
+        # TODO - Windows
+        #
+        # sys.platform == win32 Should test for
+        # signal.CTRL_BREAK_EVENT and signal.CTRL_C_EVENT and hook to
+        # appropriate callback
+
+        signal.signal(signal.SIGINT, TUI.interrupt)
-- 
2.11.0