gdbus-codegen doesn't support conditions or pre-processing. Rather than duplicating D-Bus interfaces for win32 adaptation, let's have a preprocess step, so we can have platform-specific interfaces. The python script is based on https://github.com/peitaosu/XML-Preprocessor, with bug fixes, some testing and replacing lxml dependency with the built-in xml module. This preprocessing syntax style is not very common, but is similar to the one provided by WiX (https://wixtoolset.org/docs/v3/overview/preprocessor/) or wixl, that we adopted in QEMU for packaging the guest agent. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20230606115658.677673-5-marcandre.lureau@redhat.com>
		
			
				
	
	
		
			294 lines
		
	
	
		
			8.9 KiB
		
	
	
	
		
			Python
		
	
	
		
			Executable File
		
	
	
	
	
			
		
		
	
	
			294 lines
		
	
	
		
			8.9 KiB
		
	
	
	
		
			Python
		
	
	
		
			Executable File
		
	
	
	
	
#!/usr/bin/env python3
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#
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# Copyright (c) 2017-2019 Tony Su
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# Copyright (c) 2023 Red Hat, Inc.
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#
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# SPDX-License-Identifier: MIT
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#
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# Adapted from https://github.com/peitaosu/XML-Preprocessor
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#
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"""This is a XML Preprocessor which can be used to process your XML file before
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you use it, to process conditional statements, variables, iteration
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statements, error/warning, execute command, etc.
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## XML Schema
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### Include Files
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```
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<?include path/to/file ?>
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```
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### Variables
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```
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$(env.EnvironmentVariable)
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$(sys.SystemVariable)
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$(var.CustomVariable)
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```
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### Conditional Statements
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```
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<?if ?>
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<?ifdef ?>
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<?ifndef ?>
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<?else?>
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<?elseif ?>
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<?endif?>
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```
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### Iteration Statements
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```
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<?foreach VARNAME in 1;2;3?>
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    $(var.VARNAME)
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<?endforeach?>
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```
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### Errors and Warnings
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```
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<?error "This is error message!" ?>
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<?warning "This is warning message!" ?>
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```
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### Commands
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```
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<? cmd "echo hello world" ?>
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```
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"""
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import os
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import platform
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import re
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import subprocess
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import sys
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from typing import Optional
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from xml.dom import minidom
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class Preprocessor():
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    """This class holds the XML preprocessing state"""
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    def __init__(self):
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        self.sys_vars = {
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            "ARCH": platform.architecture()[0],
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            "SOURCE": os.path.abspath(__file__),
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            "CURRENT": os.getcwd(),
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        }
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        self.cus_vars = {}
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    def _pp_include(self, xml_str: str) -> str:
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        include_regex = r"(<\?include([\w\s\\/.:_-]+)\s*\?>)"
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        matches = re.findall(include_regex, xml_str)
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        for group_inc, group_xml in matches:
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            inc_file_path = group_xml.strip()
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            with open(inc_file_path, "r", encoding="utf-8") as inc_file:
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                inc_file_content = inc_file.read()
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                xml_str = xml_str.replace(group_inc, inc_file_content)
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        return xml_str
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    def _pp_env_var(self, xml_str: str) -> str:
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        envvar_regex = r"(\$\(env\.(\w+)\))"
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        matches = re.findall(envvar_regex, xml_str)
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        for group_env, group_var in matches:
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            xml_str = xml_str.replace(group_env, os.environ[group_var])
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        return xml_str
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    def _pp_sys_var(self, xml_str: str) -> str:
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        sysvar_regex = r"(\$\(sys\.(\w+)\))"
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        matches = re.findall(sysvar_regex, xml_str)
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        for group_sys, group_var in matches:
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            xml_str = xml_str.replace(group_sys, self.sys_vars[group_var])
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        return xml_str
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    def _pp_cus_var(self, xml_str: str) -> str:
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        define_regex = r"(<\?define\s*(\w+)\s*=\s*([\w\s\"]+)\s*\?>)"
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        matches = re.findall(define_regex, xml_str)
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        for group_def, group_name, group_var in matches:
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            group_name = group_name.strip()
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            group_var = group_var.strip().strip("\"")
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            self.cus_vars[group_name] = group_var
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            xml_str = xml_str.replace(group_def, "")
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        cusvar_regex = r"(\$\(var\.(\w+)\))"
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        matches = re.findall(cusvar_regex, xml_str)
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        for group_cus, group_var in matches:
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            xml_str = xml_str.replace(
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                group_cus,
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                self.cus_vars.get(group_var, "")
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            )
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        return xml_str
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    def _pp_foreach(self, xml_str: str) -> str:
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        foreach_regex = r"(<\?foreach\s+(\w+)\s+in\s+([\w;]+)\s*\?>(.*)<\?endforeach\?>)"
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        matches = re.findall(foreach_regex, xml_str)
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        for group_for, group_name, group_vars, group_text in matches:
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            group_texts = ""
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            for var in group_vars.split(";"):
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                self.cus_vars[group_name] = var
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                group_texts += self._pp_cus_var(group_text)
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            xml_str = xml_str.replace(group_for, group_texts)
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        return xml_str
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    def _pp_error_warning(self, xml_str: str) -> str:
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        error_regex = r"<\?error\s*\"([^\"]+)\"\s*\?>"
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        matches = re.findall(error_regex, xml_str)
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        for group_var in matches:
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            raise RuntimeError("[Error]: " + group_var)
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        warning_regex = r"(<\?warning\s*\"([^\"]+)\"\s*\?>)"
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        matches = re.findall(warning_regex, xml_str)
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        for group_wrn, group_var in matches:
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            print("[Warning]: " + group_var)
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            xml_str = xml_str.replace(group_wrn, "")
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        return xml_str
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    def _pp_if_eval(self, xml_str: str) -> str:
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        ifelif_regex = (
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            r"(<\?(if|elseif)\s*([^\"\s=<>!]+)\s*([!=<>]+)\s*\"*([^\"=<>!]+)\"*\s*\?>)"
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        )
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        matches = re.findall(ifelif_regex, xml_str)
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        for ifelif, tag, left, operator, right in matches:
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            if "<" in operator or ">" in operator:
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                result = eval(f"{left} {operator} {right}")
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            else:
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                result = eval(f'"{left}" {operator} "{right}"')
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            xml_str = xml_str.replace(ifelif, f"<?{tag} {result}?>")
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        return xml_str
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    def _pp_ifdef_ifndef(self, xml_str: str) -> str:
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        ifndef_regex = r"(<\?(ifdef|ifndef)\s*([\w]+)\s*\?>)"
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        matches = re.findall(ifndef_regex, xml_str)
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        for group_ifndef, group_tag, group_var in matches:
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            if group_tag == "ifdef":
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                result = group_var in self.cus_vars
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            else:
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                result = group_var not in self.cus_vars
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            xml_str = xml_str.replace(group_ifndef, f"<?if {result}?>")
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        return xml_str
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    def _pp_if_elseif(self, xml_str: str) -> str:
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        if_elif_else_regex = (
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            r"(<\?if\s(True|False)\?>"
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            r"(.*?)"
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            r"<\?elseif\s(True|False)\?>"
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            r"(.*?)"
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            r"<\?else\?>"
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            r"(.*?)"
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            r"<\?endif\?>)"
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        )
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        if_else_regex = (
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            r"(<\?if\s(True|False)\?>"
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            r"(.*?)"
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            r"<\?else\?>"
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            r"(.*?)"
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            r"<\?endif\?>)"
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        )
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        if_regex = r"(<\?if\s(True|False)\?>(.*?)<\?endif\?>)"
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        matches = re.findall(if_elif_else_regex, xml_str, re.DOTALL)
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        for (group_full, group_if, group_if_elif, group_elif,
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             group_elif_else, group_else) in matches:
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            result = ""
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            if group_if == "True":
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                result = group_if_elif
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            elif group_elif == "True":
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                result = group_elif_else
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            else:
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                result = group_else
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            xml_str = xml_str.replace(group_full, result)
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        matches = re.findall(if_else_regex, xml_str, re.DOTALL)
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        for group_full, group_if, group_if_else, group_else in matches:
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            result = ""
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            if group_if == "True":
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                result = group_if_else
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            else:
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                result = group_else
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            xml_str = xml_str.replace(group_full, result)
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        matches = re.findall(if_regex, xml_str, re.DOTALL)
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        for group_full, group_if, group_text in matches:
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            result = ""
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            if group_if == "True":
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                result = group_text
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            xml_str = xml_str.replace(group_full, result)
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        return xml_str
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    def _pp_command(self, xml_str: str) -> str:
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        cmd_regex = r"(<\?cmd\s*\"([^\"]+)\"\s*\?>)"
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        matches = re.findall(cmd_regex, xml_str)
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        for group_cmd, group_exec in matches:
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            output = subprocess.check_output(
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                group_exec, shell=True,
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                text=True, stderr=subprocess.STDOUT
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            )
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            xml_str = xml_str.replace(group_cmd, output)
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        return xml_str
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    def _pp_blanks(self, xml_str: str) -> str:
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        right_blank_regex = r">[\n\s\t\r]*"
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        left_blank_regex = r"[\n\s\t\r]*<"
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        xml_str = re.sub(right_blank_regex, ">", xml_str)
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        xml_str = re.sub(left_blank_regex, "<", xml_str)
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        return xml_str
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    def preprocess(self, xml_str: str) -> str:
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        fns = [
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            self._pp_blanks,
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            self._pp_include,
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            self._pp_foreach,
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            self._pp_env_var,
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            self._pp_sys_var,
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            self._pp_cus_var,
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            self._pp_if_eval,
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            self._pp_ifdef_ifndef,
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            self._pp_if_elseif,
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            self._pp_command,
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            self._pp_error_warning,
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        ]
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        while True:
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            changed = False
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            for func in fns:
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                out_xml = func(xml_str)
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                if not changed and out_xml != xml_str:
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                    changed = True
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                xml_str = out_xml
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            if not changed:
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                break
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        return xml_str
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def preprocess_xml(path: str) -> str:
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    with open(path, "r", encoding="utf-8") as original_file:
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        input_xml = original_file.read()
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        proc = Preprocessor()
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        return proc.preprocess(input_xml)
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def save_xml(xml_str: str, path: Optional[str]):
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    xml = minidom.parseString(xml_str)
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    with open(path, "w", encoding="utf-8") if path else sys.stdout as output_file:
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        output_file.write(xml.toprettyxml())
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def main():
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    if len(sys.argv) < 2:
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        print("Usage: xml-preprocessor input.xml [output.xml]")
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        sys.exit(1)
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    output_file = None
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    if len(sys.argv) == 3:
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        output_file = sys.argv[2]
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    input_file = sys.argv[1]
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    output_xml = preprocess_xml(input_file)
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    save_xml(output_xml, output_file)
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if __name__ == "__main__":
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    main()
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