qemu-e2k/scripts/xml-preprocess.py
Marc-André Lureau 9b286e76c8 scripts: add a XML preprocessor script
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>
2023-06-27 17:08:56 +02:00

294 lines
8.9 KiB
Python
Executable File

#!/usr/bin/env python3
#
# Copyright (c) 2017-2019 Tony Su
# Copyright (c) 2023 Red Hat, Inc.
#
# SPDX-License-Identifier: MIT
#
# Adapted from https://github.com/peitaosu/XML-Preprocessor
#
"""This is a XML Preprocessor which can be used to process your XML file before
you use it, to process conditional statements, variables, iteration
statements, error/warning, execute command, etc.
## XML Schema
### Include Files
```
<?include path/to/file ?>
```
### Variables
```
$(env.EnvironmentVariable)
$(sys.SystemVariable)
$(var.CustomVariable)
```
### Conditional Statements
```
<?if ?>
<?ifdef ?>
<?ifndef ?>
<?else?>
<?elseif ?>
<?endif?>
```
### Iteration Statements
```
<?foreach VARNAME in 1;2;3?>
$(var.VARNAME)
<?endforeach?>
```
### Errors and Warnings
```
<?error "This is error message!" ?>
<?warning "This is warning message!" ?>
```
### Commands
```
<? cmd "echo hello world" ?>
```
"""
import os
import platform
import re
import subprocess
import sys
from typing import Optional
from xml.dom import minidom
class Preprocessor():
"""This class holds the XML preprocessing state"""
def __init__(self):
self.sys_vars = {
"ARCH": platform.architecture()[0],
"SOURCE": os.path.abspath(__file__),
"CURRENT": os.getcwd(),
}
self.cus_vars = {}
def _pp_include(self, xml_str: str) -> str:
include_regex = r"(<\?include([\w\s\\/.:_-]+)\s*\?>)"
matches = re.findall(include_regex, xml_str)
for group_inc, group_xml in matches:
inc_file_path = group_xml.strip()
with open(inc_file_path, "r", encoding="utf-8") as inc_file:
inc_file_content = inc_file.read()
xml_str = xml_str.replace(group_inc, inc_file_content)
return xml_str
def _pp_env_var(self, xml_str: str) -> str:
envvar_regex = r"(\$\(env\.(\w+)\))"
matches = re.findall(envvar_regex, xml_str)
for group_env, group_var in matches:
xml_str = xml_str.replace(group_env, os.environ[group_var])
return xml_str
def _pp_sys_var(self, xml_str: str) -> str:
sysvar_regex = r"(\$\(sys\.(\w+)\))"
matches = re.findall(sysvar_regex, xml_str)
for group_sys, group_var in matches:
xml_str = xml_str.replace(group_sys, self.sys_vars[group_var])
return xml_str
def _pp_cus_var(self, xml_str: str) -> str:
define_regex = r"(<\?define\s*(\w+)\s*=\s*([\w\s\"]+)\s*\?>)"
matches = re.findall(define_regex, xml_str)
for group_def, group_name, group_var in matches:
group_name = group_name.strip()
group_var = group_var.strip().strip("\"")
self.cus_vars[group_name] = group_var
xml_str = xml_str.replace(group_def, "")
cusvar_regex = r"(\$\(var\.(\w+)\))"
matches = re.findall(cusvar_regex, xml_str)
for group_cus, group_var in matches:
xml_str = xml_str.replace(
group_cus,
self.cus_vars.get(group_var, "")
)
return xml_str
def _pp_foreach(self, xml_str: str) -> str:
foreach_regex = r"(<\?foreach\s+(\w+)\s+in\s+([\w;]+)\s*\?>(.*)<\?endforeach\?>)"
matches = re.findall(foreach_regex, xml_str)
for group_for, group_name, group_vars, group_text in matches:
group_texts = ""
for var in group_vars.split(";"):
self.cus_vars[group_name] = var
group_texts += self._pp_cus_var(group_text)
xml_str = xml_str.replace(group_for, group_texts)
return xml_str
def _pp_error_warning(self, xml_str: str) -> str:
error_regex = r"<\?error\s*\"([^\"]+)\"\s*\?>"
matches = re.findall(error_regex, xml_str)
for group_var in matches:
raise RuntimeError("[Error]: " + group_var)
warning_regex = r"(<\?warning\s*\"([^\"]+)\"\s*\?>)"
matches = re.findall(warning_regex, xml_str)
for group_wrn, group_var in matches:
print("[Warning]: " + group_var)
xml_str = xml_str.replace(group_wrn, "")
return xml_str
def _pp_if_eval(self, xml_str: str) -> str:
ifelif_regex = (
r"(<\?(if|elseif)\s*([^\"\s=<>!]+)\s*([!=<>]+)\s*\"*([^\"=<>!]+)\"*\s*\?>)"
)
matches = re.findall(ifelif_regex, xml_str)
for ifelif, tag, left, operator, right in matches:
if "<" in operator or ">" in operator:
result = eval(f"{left} {operator} {right}")
else:
result = eval(f'"{left}" {operator} "{right}"')
xml_str = xml_str.replace(ifelif, f"<?{tag} {result}?>")
return xml_str
def _pp_ifdef_ifndef(self, xml_str: str) -> str:
ifndef_regex = r"(<\?(ifdef|ifndef)\s*([\w]+)\s*\?>)"
matches = re.findall(ifndef_regex, xml_str)
for group_ifndef, group_tag, group_var in matches:
if group_tag == "ifdef":
result = group_var in self.cus_vars
else:
result = group_var not in self.cus_vars
xml_str = xml_str.replace(group_ifndef, f"<?if {result}?>")
return xml_str
def _pp_if_elseif(self, xml_str: str) -> str:
if_elif_else_regex = (
r"(<\?if\s(True|False)\?>"
r"(.*?)"
r"<\?elseif\s(True|False)\?>"
r"(.*?)"
r"<\?else\?>"
r"(.*?)"
r"<\?endif\?>)"
)
if_else_regex = (
r"(<\?if\s(True|False)\?>"
r"(.*?)"
r"<\?else\?>"
r"(.*?)"
r"<\?endif\?>)"
)
if_regex = r"(<\?if\s(True|False)\?>(.*?)<\?endif\?>)"
matches = re.findall(if_elif_else_regex, xml_str, re.DOTALL)
for (group_full, group_if, group_if_elif, group_elif,
group_elif_else, group_else) in matches:
result = ""
if group_if == "True":
result = group_if_elif
elif group_elif == "True":
result = group_elif_else
else:
result = group_else
xml_str = xml_str.replace(group_full, result)
matches = re.findall(if_else_regex, xml_str, re.DOTALL)
for group_full, group_if, group_if_else, group_else in matches:
result = ""
if group_if == "True":
result = group_if_else
else:
result = group_else
xml_str = xml_str.replace(group_full, result)
matches = re.findall(if_regex, xml_str, re.DOTALL)
for group_full, group_if, group_text in matches:
result = ""
if group_if == "True":
result = group_text
xml_str = xml_str.replace(group_full, result)
return xml_str
def _pp_command(self, xml_str: str) -> str:
cmd_regex = r"(<\?cmd\s*\"([^\"]+)\"\s*\?>)"
matches = re.findall(cmd_regex, xml_str)
for group_cmd, group_exec in matches:
output = subprocess.check_output(
group_exec, shell=True,
text=True, stderr=subprocess.STDOUT
)
xml_str = xml_str.replace(group_cmd, output)
return xml_str
def _pp_blanks(self, xml_str: str) -> str:
right_blank_regex = r">[\n\s\t\r]*"
left_blank_regex = r"[\n\s\t\r]*<"
xml_str = re.sub(right_blank_regex, ">", xml_str)
xml_str = re.sub(left_blank_regex, "<", xml_str)
return xml_str
def preprocess(self, xml_str: str) -> str:
fns = [
self._pp_blanks,
self._pp_include,
self._pp_foreach,
self._pp_env_var,
self._pp_sys_var,
self._pp_cus_var,
self._pp_if_eval,
self._pp_ifdef_ifndef,
self._pp_if_elseif,
self._pp_command,
self._pp_error_warning,
]
while True:
changed = False
for func in fns:
out_xml = func(xml_str)
if not changed and out_xml != xml_str:
changed = True
xml_str = out_xml
if not changed:
break
return xml_str
def preprocess_xml(path: str) -> str:
with open(path, "r", encoding="utf-8") as original_file:
input_xml = original_file.read()
proc = Preprocessor()
return proc.preprocess(input_xml)
def save_xml(xml_str: str, path: Optional[str]):
xml = minidom.parseString(xml_str)
with open(path, "w", encoding="utf-8") if path else sys.stdout as output_file:
output_file.write(xml.toprettyxml())
def main():
if len(sys.argv) < 2:
print("Usage: xml-preprocessor input.xml [output.xml]")
sys.exit(1)
output_file = None
if len(sys.argv) == 3:
output_file = sys.argv[2]
input_file = sys.argv[1]
output_xml = preprocess_xml(input_file)
save_xml(output_xml, output_file)
if __name__ == "__main__":
main()