103 lines
2.5 KiB
Python
103 lines
2.5 KiB
Python
'''
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Context
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=======
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.. versionadded:: 1.8.0
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.. warning::
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This is experimental and subject to change as long as this warning notice
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is present.
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Kivy has a few "global" instances that are used directly by many pieces of the
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framework: `Cache`, `Builder`, `Clock`.
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TODO: document this module.
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'''
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__all__ = ('Context', 'ProxyContext', 'register_context',
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'get_current_context')
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_contexts = {}
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_default_context = None
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_context_stack = []
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class ProxyContext(object):
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__slots__ = ['_obj']
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def __init__(self, obj):
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object.__init__(self)
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object.__setattr__(self, '_obj', obj)
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def __getattribute__(self, name):
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return getattr(object.__getattribute__(self, '_obj'), name)
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def __delattr__(self, name):
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delattr(object.__getattribute__(self, '_obj'), name)
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def __setattr__(self, name, value):
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setattr(object.__getattribute__(self, '_obj'), name, value)
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def __bool__(self):
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return bool(object.__getattribute__(self, '_obj'))
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def __str__(self):
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return str(object.__getattribute__(self, '_obj'))
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def __repr__(self):
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return repr(object.__getattribute__(self, '_obj'))
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class Context(dict):
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def __init__(self, init=False):
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dict.__init__(self)
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self.sandbox = None
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if not init:
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return
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for name in _contexts:
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context = _contexts[name]
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instance = context['cls'](*context['args'], **context['kwargs'])
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self[name] = instance
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def push(self):
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_context_stack.append(self)
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for name, instance in self.items():
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object.__setattr__(_contexts[name]['proxy'], '_obj', instance)
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def pop(self):
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# After popping context from stack. Update proxy's _obj with
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# instances in current context
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_context_stack.pop(-1)
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for name, instance in get_current_context().items():
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object.__setattr__(_contexts[name]['proxy'], '_obj', instance)
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def register_context(name, cls, *args, **kwargs):
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'''Register a new context.
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'''
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instance = cls(*args, **kwargs)
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proxy = ProxyContext(instance)
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_contexts[name] = {
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'cls': cls,
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'args': args,
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'kwargs': kwargs,
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'proxy': proxy}
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_default_context[name] = instance
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return proxy
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def get_current_context():
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'''Return the current context.
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'''
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if not _context_stack:
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return _default_context
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return _context_stack[-1]
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_default_context = Context(init=False)
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