Add Windows driver

Generate C header file based on layout description and create a source
bundle that must be compiled on a Windows system and then moved back to
the source tree. This sucks, but cross-compiling on Linux is a pain,
since Windows’ development headers assume a case-insensitive filesystem.
Also I’m using MSKLC because the latest driver development kit cannot
compile these drivers correctly. Dear @microsoft, please fix your shit:
https://github.com/microsoft/Windows-driver-samples/issues/433

A remaining concern right now is licensing. keyboard.{c,h,def,rc} have
been copied from a project generated by MSKLC and are probably non-free,
although pretty much identical files like
https://github.com/microsoft/Windows-driver-samples/blob/master/input/layout/kbdus/kbdus.c
are covered by MS-PL.

Also binds backspace key to \b and adjusts xmodmap/svg rendering
accordingly.

See #7.

1 files changed, 253 insertions, 4 deletions

diff --git a/lulua/render.py b/lulua/render.py
index be3bf68..3bde0b7 100644
--- a/lulua/render.py
+++ b/lulua/render.py
@@ -290,10 +290,7 @@ def renderXmodmap (args):
                 if not layout.isModifier (frozenset ([btn])):
                     text = l.layout.get (btn)
                     if not text:
-                        if btn.name == 'Br_bs' and i == 0:
-                            text = 'BackSpace'
-                        else:
-                            text = 'NoSymbol'
+                        text = 'NoSymbol'
                     else:
                         # some keys cannot be represented by unicode
                         # characters and must be mapped
@@ -301,6 +298,7 @@ def renderXmodmap (args):
                             '\t': 'Tab',
                             '\n': 'Return',
                             ' ': 'space',
+                            '\b': 'BackSpace',
                             }
                         text = specialMap.get (text, f'U{ord (text):04X}')
                     keycodeMap[btn].append (text)
@@ -426,6 +424,255 @@ def renderAsk (args):
     tree = ET.ElementTree (kbdelem)
     tree.write (args.output, encoding='utf-8', xml_declaration=True)
 
+def renderWinKbd (args):
+    keyboard = defaultKeyboards[args.keyboard]
+    layout = defaultLayouts[args.layout].specialize (keyboard)
+
+    if args.layout != 'ar-lulua':
+        logging.error (f'due to the delicate relationship between virtual keys and text output this command will probably not produce working files for your layout. Please have a look at renderWinKbd() in {__file__} and fix the code.')
+        return
+
+    resPath = pkg_resources.resource_filename (__package__, 'data/winkbd')
+
+    with open (args.output, 'w') as fd:
+        lines = []
+        lines.append (f'/* This header was auto-generated by {__package__}. It is included by {resPath}/keyboard.h. Do not modify. */')
+        lines.append ('')
+
+        # copied from kbdneo2.c as well
+        # XXX: modifier keys are fixed for now
+        # maps virtual keys (first value) to shift bitfield value (second value)
+        lines.append ('#define MODIFIER_BITS\\')
+        lines.append ("""    { VK_SHIFT		,	KBDSHIFT	}, \\
+    { VK_CONTROL	,	KBDCTRL		},    \\
+    { VK_MENU		,	KBDALT		}, \\
+    { VK_OEM_8		,	KBDKANA		}, \\
+    { VK_OEM_102	,	16			},""")
+
+        # copied from kbdneo2.c
+        # maps a shift bitfield value (array index) to a layer number in
+        # virtual key translation (VK_TO_WCHARS, array value)
+        lines.append ('#define CHAR_MODIFIERS_MASK 24')
+        lines.append ('#define CHAR_MODIFIERS\\')
+        lines.append ('\t{ 0, 1, 6, 7, SHFT_INVALID, SHFT_INVALID, SHFT_INVALID, SHFT_INVALID, 3, 8, SHFT_INVALID, SHFT_INVALID, SHFT_INVALID, SHFT_INVALID, SHFT_INVALID, SHFT_INVALID, 2, 4, SHFT_INVALID, SHFT_INVALID, SHFT_INVALID, SHFT_INVALID, SHFT_INVALID, SHFT_INVALID, 5, }')
+
+        # this is the standard layout from windows’ kbd.h (for KBD_TYPE == 4)
+        scancodeToVk = {
+            'T01': 'ESCAPE',
+            'T02': '1',
+            'T03': '2',
+            'T04': '3',
+            'T05': '4',
+            'T06': '5',
+            'T07': '6',
+            'T08': '7',
+            'T09': '8',
+            'T0A': '9',
+            'T0B': '0',
+            'T0C': 'OEM_MINUS',
+            'T0D': 'OEM_PLUS',
+            'T0E': 'BACK',
+            'T0F': 'TAB',
+            'T10': 'Q',
+            'T11': 'W',
+            'T12': 'E',
+            'T13': 'R',
+            'T14': 'T',
+            'T15': 'Y',
+            'T16': 'U',
+            'T17': 'I',
+            'T18': 'O',
+            'T19': 'P',
+            'T1A': 'OEM_4',
+            'T1B': 'OEM_6',
+            'T1C': 'RETURN',
+            'T1D': 'LCONTROL',
+            'T1E': 'A',
+            'T1F': 'S',
+            'T20': 'D',
+            'T21': 'F',
+            'T22': 'G',
+            'T23': 'H',
+            'T24': 'J',
+            'T25': 'K',
+            'T26': 'L',
+            'T27': 'OEM_1',
+            'T28': 'OEM_7',
+            'T29': 'OEM_3',
+            'T2A': 'LSHIFT',
+            'T2B': 'OEM_5',
+            'T2C': 'Z',
+            'T2D': 'X',
+            'T2E': 'C',
+            'T2F': 'V',
+            'T30': 'B',
+            'T31': 'N',
+            'T32': 'M',
+            'T33': 'OEM_COMMA',
+            'T34': 'OEM_PERIOD',
+            'T35': 'OEM_2',
+            'T36': 'RSHIFT',
+            'T37': 'MULTIPLY',
+            'T38': 'LMENU',
+            'T39': 'SPACE',
+            'T3A': 'CAPITAL',
+            'T3B': 'F1',
+            'T3C': 'F2',
+            'T3D': 'F3',
+            'T3E': 'F4',
+            'T3F': 'F5',
+            'T40': 'F6',
+            'T41': 'F7',
+            'T42': 'F8',
+            'T43': 'F9',
+            'T44': 'F10',
+            'T45': 'NUMLOCK',
+            'T46': 'SCROLL',
+            'T47': 'HOME',
+            'T48': 'UP',
+            'T49': 'PRIOR',
+            'T4A': 'SUBTRACT',
+            'T4B': 'LEFT',
+            'T4C': 'CLEAR',
+            'T4D': 'RIGHT',
+            'T4E': 'ADD',
+            'T4F': 'END',
+            'T50': 'DOWN',
+            'T51': 'NEXT',
+            'T52': 'INSERT',
+            'T53': 'DELETE',
+            'T54': 'SNAPSHOT',
+            'T56': 'OEM_102',
+            'T57': 'F11',
+            'T58': 'F12',
+            'T59': 'CLEAR',
+            'T5A': 'OEM_WSCTRL',
+            'T5B': 'OEM_FINISH',
+            'T5C': 'OEM_JUMP',
+            'T5D': 'EREOF',
+            'T5E': 'OEM_BACKTAB',
+            'T5F': 'OEM_AUTO',
+            'T62': 'ZOOM',
+            'T63': 'HELP',
+            'T64': 'F13',
+            'T65': 'F14',
+            'T66': 'F15',
+            'T67': 'F16',
+            'T68': 'F17',
+            'T69': 'F18',
+            'T6A': 'F19',
+            'T6B': 'F20',
+            'T6C': 'F21',
+            'T6D': 'F22',
+            'T6E': 'F23',
+            'T6F': 'OEM_PA3',
+            'T71': 'OEM_RESET',
+            'T73': 'ABNT_C1',
+            'T76': 'F24',
+            'T7B': 'OEM_PA1',
+            'T7C': 'TAB',
+            'T7E': 'ABNT_C2',
+            'T7F': 'OEM_PA2',
+
+            'X10': 'MEDIA_PREV_TRACK',
+            'X19': 'MEDIA_NEXT_TRACK',
+            'X1C': 'RETURN',
+            'X1D': 'RCONTROL',
+            'X20': 'VOLUME_MUTE',
+            'X21': 'LAUNCH_APP2',
+            'X22': 'MEDIA_PLAY_PAUSE',
+            'X24': 'MEDIA_STOP',
+            'X2E': 'VOLUME_DOWN',
+            'X30': 'VOLUME_UP',
+            'X32': 'BROWSER_HOME',
+            'X35': 'DIVIDE',
+            'X37': 'SNAPSHOT',
+            'X38': 'RMENU',
+            'X46': 'CANCEL',
+            'X47': 'HOME',
+            'X48': 'UP',
+            'X49': 'PRIOR',
+            'X4B': 'LEFT',
+            'X4D': 'RIGHT',
+            'X4F': 'END',
+            'X50': 'DOWN',
+            'X51': 'NEXT',
+            'X52': 'INSERT',
+            'X53': 'DELETE',
+            'X5B': 'LWIN',
+            'X5C': 'RWIN',
+            'X5D': 'APPS',
+            'X5E': 'POWER',
+            'X5F': 'SLEEP',
+            'X65': 'BROWSER_SEARCH',
+            'X66': 'BROWSER_FAVORITES',
+            'X67': 'BROWSER_REFRESH',
+            'X68': 'BROWSER_STOP',
+            'X69': 'BROWSER_FORWARD',
+            'X6A': 'BROWSER_BACK',
+            'X6B': 'LAUNCH_APP1',
+            'X6C': 'LAUNCH_MAIL',
+            'X6D': 'LAUNCH_MEDIA_SELECT',
+            }
+        # modifications copied from kbdneo2.c
+        # maps modifier keys to oem values used above.
+        scancodeToVk.update ({
+            # mod 3
+            'T2B': 'OEM_102',
+            'T3A': 'OEM_102',
+            # mod 4
+            'X38': 'OEM_8',
+            'T56': 'OEM_8',
+            })
+        for k, v in scancodeToVk.items ():
+            lines.append (f'#undef {k}')
+            if len (v) == 1:
+                # character value if not symbolic
+                v = f"'{v}'"
+            lines.append (f'#define {k} _EQ({v})')
+        lines.append ('')
+
+        lines.append ('#define VK_TO_WCH6 \\')
+        for btn in unique (keyboard.keys (), key=attrgetter ('windowsScancode')):
+            def toUnicode (s):
+                if s is None:
+                    return 'WCH_NONE'
+                elif len (s) != 1:
+                    logging.error (f'only single-character strings are supported, ignoring {s}')
+                    return 'WCH_NONE'
+                elif s == '\n':
+                    # convert to windows-convention
+                    s = '\r'
+                return f'0x{ord (s):x} /*{repr (s)}*/'
+
+            text = list (layout.getButtonText (btn))
+            assert len (text) < 7, "supporting six layers only right now"
+
+            # skip unused keys
+            if sum (map (lambda x: 1 if x is not None else 0, text)) == 0:
+                continue
+
+            # fixed-length array, need padding
+            mappedText = [toUnicode (s) for s in text]
+            while len (mappedText) < 6:
+                mappedText.append ('WCH_NONE')
+
+            vk = scancodeToVk[btn.windowsScancode]
+            if len (vk) == 1:
+                # character value
+                vk = f"'{vk}'"
+            else:
+                # symbolic value
+                vk = f'VK_{vk}'
+            mappingStr = ', '.join (mappedText)
+            lines.append (f'\t{{ {vk}, 0, {mappingStr} }}, \\')
+        # NUL-termination entry is already present in keyboard.c
+        lines.append ('\n')
+
+        fd.write ('\n'.join (lines))
+    logging.info ('refer to README.rst on how to build a windows driver. '
+            f'Template files are located in {resPath}')
+
 def yamlload (s):
     try:
         with open (s) as fd:
@@ -458,6 +705,8 @@ def render ():
     sp.set_defaults (func=renderKeyman)
     sp = subparsers.add_parser('ask')
     sp.set_defaults (func=renderAsk)
+    sp = subparsers.add_parser('winkbd')
+    sp.set_defaults (func=renderWinKbd)
     parser.add_argument('output', metavar='FILE', help='Output file')
 
     logging.basicConfig (level=logging.INFO)