vk-bootstrap/script/generate_dispatch.py

#
# generate_dispatch.py
# 
# Copyright © 2021 Cody Goodson (contact@vibimanx.com)
#
# Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
# documentation files (the “Software”), to deal in the Software without restriction, including without
# limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
# of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
# LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

# This file is a part of VkBootstrap
# https://github.com/charles-lunarg/vk-bootstrap

# On run, vk.xml is pulled from the master of Khronos's Vulkan-Headers repo and a VkBoostrapDispatch header
# is generated and placed in VkBoostrap's source directory
# https://raw.githubusercontent.com/KhronosGroup/Vulkan-Headers/master/registry/vk.xml

# This script makes use of xmltodict
# https://github.com/martinblech/xmltodict
# User will be prompted to install if not detected

# Exclusions
exclusions = [
	'vkGetDeviceProcAddr',
	'vkCreateDevice',
	'vkDestroyDevice'
]

# Check for/install xmltodict
import sys
import subprocess
import pkg_resources
import copy
from string import Template

installed = {pkg.key for pkg in pkg_resources.working_set}
xmltodict_missing = {'xmltodict'} - installed

# Install xmltodict
if xmltodict_missing:
	val = input("xmltodict is required to run this script. Would you like to install? (y/n): ");
	if(val.lower() == "y"):
		try:
			subprocess.check_call([sys.executable, '-m', 'pip', 'install', 'xmltodict'])
		except subprocess.CalledProcessError as error:
			print("Failed to install xmltodict due to error:");
			print(error);
			input("Press Enter to continue...");
			sys.exit();
	else:
		sys.exit();

# Fetch fresh vk.xml from Khronos repo
import urllib.request
import xmltodict

try: 
	response = urllib.request.urlopen('https://raw.githubusercontent.com/KhronosGroup/Vulkan-Headers/master/registry/vk.xml')
except urllib.error.URLError as error:
	print("Failed to download vk.xml due to error:");
	print(error.reason)
	input("Press Enter to continue...");
	sys.exit();
vk_xml_raw = response.read()

vk_xml = xmltodict.parse(vk_xml_raw,process_namespaces=True)

command_params = {'return_type': '', 'args': [], 'requirements': [], 'macro_template': Template('')}

device_commands = {}

# Gather all device functions/aliases for filtering core/extension function fetching
commands_node = vk_xml['registry']['commands']['command']
aliases = {}
for command_node in commands_node:
	if 'proto' in command_node:
		command_name = command_node['proto']['name']
		new_command_params = copy.deepcopy(command_params)
		new_command_params['return_type'] = command_node['proto']['type']
		if type(command_node['param']) is list:
			new_command_params['args'] = command_node['param']
		else:
			new_command_params['args'] = [command_node['param']]
		if not command_name in exclusions:
			if new_command_params['args'][0]['type'] == 'VkDevice' or new_command_params['args'][0]['type'] == 'VkCommandBuffer' or new_command_params['args'][0]['type'] == 'VkQueue':
				device_commands[command_name] = new_command_params
	elif '@alias' in command_node:
		aliases[command_node['@alias']] = command_node['@name'];

# Push the alias name as a device function if the alias exists in device commands
for alias in aliases:
	if alias in device_commands:
		aliased_command_params = device_commands[alias].copy()
		device_commands[aliases[alias]] = aliased_command_params;

# Add requirements for core PFN's
features_node = vk_xml['registry']['feature']
for feature_node in features_node:
	if feature_node['@name'] != 'VK_VERSION_1_0':
		for require_node in feature_node['require']:
			for param_node in require_node:
				if param_node == 'command':
					if type(require_node[param_node]) is not list:
						require_node[param_node] = [require_node[param_node]]
					for param in require_node[param_node]:
						if param['@name'] in device_commands:
							device_commands[param['@name']]['requirements'] += [[feature_node['@name']]]


# Add requirements for extension PFN's
extensions_node = vk_xml['registry']['extensions']['extension']
for extension_node in extensions_node:
	extension_name = extension_node['@name']
	if 'require' in extension_node.keys():
		require_nodes = extension_node['require']
		for require_node in require_nodes:
			requirements = [extension_name];
			if type(require_node) is not str:
				if 'command' in require_node.keys():
					if '@feature' in require_node.keys():
						requirements.append(require_node['@feature'])
					if '@extension' in require_node.keys():
						requirements.append(require_node['@extension'])
					if type(require_node['command']) is not list:
						require_node['command'] = [require_node['command']]
					for command_node in require_node['command']:
						if command_node['@name'] in device_commands:
							device_commands[command_node['@name']]['requirements'] += [requirements]
			elif require_node == 'command':
				if type(require_nodes['command']) is not list:
					require_nodes['command'] = [require_nodes['command']]
				for command_node in require_nodes['command']:
					if command_node['@name'] in device_commands:
						device_commands[command_node['@name']]['requirements'] += [requirements]

# Generate macro templates
for command in device_commands:
	macro = ''
	requirements_collection = device_commands[command]['requirements']
	collection_count = len(requirements_collection)
	if collection_count > 0:
		macro = '#if '
		while(collection_count > 0):
			for requirements in requirements_collection:
				requirements_count = len(requirements)
				macro += '('
				for requirement in requirements:
					macro += 'defined({})'.format(requirement)
					requirements_count -= 1
					if requirements_count > 0:
						macro += ' && '
				macro += ')'
				if collection_count > 0:
					collection_count -= 1
					if collection_count > 0:
				 		macro += ' || '
		macro += '\n$body#endif\n'
	else:
		macro = '$body'
	device_commands[command]['macro_template'] = Template(macro)

# License
license = '/* \n'
license += ' * Copyright © 2021 Cody Goodson (contact@vibimanx.com)\n'
license += ' * \n'
license += ' * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated\n'
license += ' * documentation files (the “Software”), to deal in the Software without restriction, including without\n'
license += ' * limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies\n'
license += ' * of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:\n'
license += ' * \n'
license += ' * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.\n'
license += ' * \n'
license += ' * THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT\n'
license += ' * LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.\n'
license += ' * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,\n'
license += ' * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.\n'
license += ' * \n'
license += ' */\n\n'

# Info
info = '// This file is a part of VkBootstrap\n'
info += '// https://github.com/charles-lunarg/vk-bootstrap\n\n'

# # Content
body = '\n#pragma once\n\n#include <vulkan/vulkan.h>\n\n'
body += 'namespace vkb {\n\n'
body += 'struct DispatchTable {\n'
body += '\tDispatchTable() = default;\n'
body += '\tDispatchTable(VkDevice device, PFN_vkGetDeviceProcAddr procAddr) : device(device), populated(true) {\n'

proxy_section = ''
fp_decl_section = ''
pfn_load_section = ''

proxy_template = Template('\t$return_type $proxy_name($args_full) const noexcept {\n\t\t$opt_return$fp_name($args_names);\n\t}\n')
fp_decl_template = Template('\t$pfn_name $fp_name = nullptr;\n')
pfn_load_template = Template('\t\t$fp_name = ($pfn_name)procAddr(device, "$command_name");\n')

for command in device_commands:
	params = device_commands[command]
	# easy stuff out of the way
	return_type = params['return_type']
	if(return_type != 'void'):
		opt_return = 'return '
	else:
		opt_return = ''
	proxy_name = command[2].lower() + command[3:]
	fp_name = 'fp_' + command
	pfn_name = 'PFN_' + command

	# Now for args
	arg_template = Template('$front_mods$arg_type$back_mods$arg_name$array')
	args_full = ''
	args_names = ''
	args_count = len(params['args'])
	i = args_count
	for arg in params['args']:
		front_mods = '';
		back_mods = ' ';
		array = '';
		arg_type = arg['type']
		arg_name = arg['name']
		if '#text' in arg:
			text = arg['#text']
			text = text.replace(' ', '')
			array_index = text.find('[')
			if array_index != -1:
				array = text[array_index:]
				text = text[0:array_index]
			if text == '*':
				front_mods = ''
				back_mods = '* '
			elif text == '**':
				front_mods = ''
				back_mods = '** '
			elif text == 'const*':
				front_mods = 'const '
				back_mods = '* '
			elif text == 'const**':
				front_mods = 'const '
				back_mods = '** '
			elif text == 'const*const*':
				front_mods = 'const '
				back_mods = '* const* '
		if i == args_count and arg_type == 'VkDevice':
			args_names += arg_name
			if i > 0:
				i -= 1
				if i > 0:
			 		args_names += ', '
		else:
			args_full += arg_template.substitute(front_mods = front_mods, arg_type = arg_type, back_mods = back_mods, arg_name = arg_name, array = array)
			args_names += arg_name
			if i > 0:
				i -= 1
				if i > 0:
			 		args_full += ', '
			 		args_names += ', '

	proxy_body = proxy_template.substitute(return_type = return_type, proxy_name = proxy_name, args_full = args_full, opt_return = opt_return, fp_name = fp_name, args_names = args_names)
	fp_decl_body = fp_decl_template.substitute(pfn_name = pfn_name, fp_name = fp_name)
	pfn_load_body = pfn_load_template.substitute(fp_name = fp_name, pfn_name = pfn_name, command_name = command)

	macro_template = params['macro_template']
	proxy_section += macro_template.substitute(body=proxy_body)
	fp_decl_section += macro_template.substitute(body=fp_decl_body)
	pfn_load_section +=macro_template.substitute(body=pfn_load_body)

body += pfn_load_section
body += '\t}\n'
body += proxy_section
body += fp_decl_section
body += '\tbool is_populated() const { return populated; }\n'
body += '\tVkDevice device = VK_NULL_HANDLE;\n'
body += 'private:\n'
body += '\t bool populated = false;\n'
body += '};\n\n'
body += '} // namespace vkb'

header = license + info + body

header_file = open("../src/VkBootstrapDispatch.h", "w")
header_file.write(header)
header_file.close();

input("Generation finished. Press Enter to continue...")