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#############################################################################
##
## Copyright (C) 2020 The Qt Company Ltd.
## Contact: https://www.qt.io/licensing/
##
## This file is part of the Qt for Python project.
##
## $QT_BEGIN_LICENSE:LGPL$
## Commercial License Usage
## Licensees holding valid commercial Qt licenses may use this file in
## accordance with the commercial license agreement provided with the
## Software or, alternatively, in accordance with the terms contained in
## a written agreement between you and The Qt Company. For licensing terms
## and conditions see https://www.qt.io/terms-conditions. For further
## information use the contact form at https://www.qt.io/contact-us.
##
## GNU Lesser General Public License Usage
## Alternatively, this file may be used under the terms of the GNU Lesser
## General Public License version 3 as published by the Free Software
## Foundation and appearing in the file LICENSE.LGPL3 included in the
## packaging of this file. Please review the following information to
## ensure the GNU Lesser General Public License version 3 requirements
## will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
##
## GNU General Public License Usage
## Alternatively, this file may be used under the terms of the GNU
## General Public License version 2.0 or (at your option) the GNU General
## Public license version 3 or any later version approved by the KDE Free
## Qt Foundation. The licenses are as published by the Free Software
## Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
## included in the packaging of this file. Please review the following
## information to ensure the GNU General Public License requirements will
## be met: https://www.gnu.org/licenses/gpl-2.0.html and
## https://www.gnu.org/licenses/gpl-3.0.html.
##
## $QT_END_LICENSE$
##
#############################################################################
"""C++ formatting helper functions and formatter class"""
import ast
import sys
CLOSING = {"{": "}", "(": ")", "[": "]"} # Closing parenthesis for C++
def to_string(node):
"""Helper to retrieve a string from the (Lists of)Name/Attribute
aggregated into some nodes"""
if isinstance(node, ast.Name):
return node.id
if isinstance(node, ast.Attribute):
return node.attr
return ''
def format_inheritance(class_def_node):
"""Returns inheritance specification of a class"""
result = ''
for base in class_def_node.bases:
name = to_string(base)
if name != 'object':
result += ', public ' if result else ' : public '
result += name
return result
def format_for_target(target_node):
if isinstance(target_node, ast.Tuple): # for i,e in enumerate()
result = ''
for i, el in enumerate(target_node):
if i > 0:
result += ', '
result += format_reference(el)
return result
return format_reference(target_node)
def format_for_loop(f_node):
"""Format a for loop
This applies some heuristics to detect:
1) "for a in [1,2])" -> "for (f: {1, 2}) {"
2) "for i in range(5)" -> "for (i = 0; i < 5; ++i) {"
3) "for i in range(2,5)" -> "for (i = 2; i < 5; ++i) {"
TODO: Detect other cases, maybe including enumerate().
"""
loop_vars = format_for_target(f_node.target)
result = 'for (' + loop_vars
if isinstance(f_node.iter, ast.Call):
f = format_reference(f_node.iter.func)
if f == 'range':
start = 0
end = -1
if len(f_node.iter.args) == 2:
start = format_literal(f_node.iter.args[0])
end = format_literal(f_node.iter.args[1])
elif len(f_node.iter.args) == 1:
end = format_literal(f_node.iter.args[0])
result += f' = {start}; {loop_vars} < {end}; ++{loop_vars}'
elif isinstance(f_node.iter, ast.List):
# Range based for over list
result += ': ' + format_literal_list(f_node.iter)
result += ') {'
return result
def format_literal(node):
"""Returns the value of number/string literals"""
if isinstance(node, ast.Num):
return str(node.n)
if isinstance(node, ast.Str):
# Fixme: escaping
return f'"{node.s}"'
return ''
def format_literal_list(l_node, enclosing='{'):
"""Formats a list/tuple of number/string literals as C++ initializer list"""
result = enclosing
for i, el in enumerate(l_node.elts):
if i > 0:
result += ', '
result += format_literal(el)
result += CLOSING[enclosing]
return result
def format_member(attrib_node, qualifier='auto'):
"""Member access foo->member() is expressed as an attribute with
further nested Attributes/Names as value"""
n = attrib_node
result = ''
# Black magic: Guess '::' if name appears to be a class name
if qualifier == 'auto':
qualifier = '::' if n.attr[0:1].isupper() else '->'
while isinstance(n, ast.Attribute):
result = n.attr if not result else n.attr + qualifier + result
n = n.value
if isinstance(n, ast.Name) and n.id != 'self':
result = n.id + qualifier + result
return result
def format_reference(node, qualifier='auto'):
"""Format member reference or free item"""
return node.id if isinstance(node, ast.Name) else format_member(node, qualifier)
def format_function_def_arguments(function_def_node):
"""Formats arguments of a function definition"""
# Default values is a list of the last default values, expand
# so that indexes match
argument_count = len(function_def_node.args.args)
default_values = function_def_node.args.defaults
while len(default_values) < argument_count:
default_values.insert(0, None)
result = ''
for i, a in enumerate(function_def_node.args.args):
if result:
result += ', '
if a.arg != 'self':
result += a.arg
if default_values[i]:
result += ' = '
result += format_literal(default_values[i])
return result
def format_start_function_call(call_node):
"""Format a call of a free or member function"""
return format_reference(call_node.func) + '('
def write_import(file, i_node):
"""Print an import of a Qt class as #include"""
for alias in i_node.names:
if alias.name.startswith('Q'):
file.write(f'#include <{alias.name}>\n')
def write_import_from(file, i_node):
"""Print an import from Qt classes as #include sequence"""
# "from PySide2.QtGui import QGuiApplication" or
# "from PySide2 import QtGui"
mod = i_node.module
if not mod.startswith('PySide') and not mod.startswith('PyQt'):
return
dot = mod.find('.')
qt_module = mod[dot + 1:] + '/' if dot >= 0 else ''
for i in i_node.names:
if i.name.startswith('Q'):
file.write(f'#include <{qt_module}{i.name}>\n')
class Indenter:
"""Helper for Indentation"""
def __init__(self, output_file):
self._indent_level = 0
self._indentation = ''
self._output_file = output_file
def indent_string(self, string):
"""Start a new line by a string"""
self._output_file.write(self._indentation)
self._output_file.write(string)
def indent_line(self, line):
"""Write an indented line"""
self._output_file.write(self._indentation)
self._output_file.write(line)
self._output_file.write('\n')
def INDENT(self):
"""Write indentation"""
self._output_file.write(self._indentation)
def indent(self):
"""Increase indentation level"""
self._indent_level = self._indent_level + 1
self._indentation = ' ' * self._indent_level
def dedent(self):
"""Decrease indentation level"""
self._indent_level = self._indent_level - 1
self._indentation = ' ' * self._indent_level
class CppFormatter(Indenter):
"""Provides helpers for formatting multi-line C++ constructs"""
def __init__(self, output_file):
Indenter.__init__(self, output_file)
def write_class_def(self, class_node):
"""Print a class definition with inheritance"""
self._output_file.write('\n')
inherits = format_inheritance(class_node)
self.indent_line(f'class {class_node.name}{inherits}')
self.indent_line('{')
self.indent_line('public:')
def write_function_def(self, f_node, class_context):
"""Print a function definition with arguments"""
self._output_file.write('\n')
arguments = format_function_def_arguments(f_node)
warn = True
if f_node.name == '__init__' and class_context: # Constructor
name = class_context
warn = len(arguments) > 0
elif f_node.name == '__del__' and class_context: # Destructor
name = '~' + class_context
warn = False
else:
name = 'void ' + f_node.name
self.indent_string(f'{name}({arguments})')
if warn:
self._output_file.write(' /* FIXME: types */')
self._output_file.write('\n')
self.indent_line('{')
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