/
_proxies.py
182 lines (135 loc) · 4.68 KB
/
_proxies.py
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"""Proxies for global default variables that can be updated."""
import datetime
import logging
import sqlalchemy as sa
from . import _tools
__all__ = ['PathProxy', 'SQLiteEngineProxy']
log = logging.getLogger(__name__)
class Proxy(object):
_delegate = None
def __getattr__(self, name):
return getattr(self._delegate, name)
def __repr__(self):
return f'<{self.__module__}.{self.__class__.__name__}>'
class PathProxy(Proxy):
"""
>>> PathProxy()
<treedb._proxies.PathProxy>
>>> assert PathProxy().inode() is None
>>> import pathlib
>>> PathProxy(pathlib.Path())
<treedb._proxies.PathProxy path='.' inode=...>
>>> print(PathProxy(pathlib.Path()))
.
"""
def __init__(self, path=None):
self.path = path
def __fspath__(self):
return self._delegate.__fspath__()
def __str__(self):
if self._delegate is None:
raise RuntimeError('str() on empty path proxy')
return str(self._delegate)
@property
def path(self):
return self._delegate
@path.setter
def path(self, path):
if path is not None:
path = _tools.path_from_filename(path)
log.debug('set path of %r to %r', self, path)
self._delegate = path
def __repr__(self):
if self.path is None:
return super().__repr__()
return (f'<{self.__module__}.{self.__class__.__name__}'
f' path={self.path.as_posix()!r}'
f' inode={self.inode()!r}>')
def inode(self):
if self.path is None or not self.path.exists():
return None
return self.path.stat().st_ino
class EngineProxy(Proxy, sa.engine.Engine):
"""
>>> EngineProxy(future=True)
<treedb._proxies.EngineProxy>
"""
def __init__(self, engine=None, *, future):
self.engine = engine
self.future = future
def _create_engine(self, url):
log.debug('sqlalchemy.create_engine(%r)', url)
self.engine = sa.create_engine(url, future=self.future)
def connect(self, close_with_result=False, **kwargs):
return self.engine.connect(**kwargs)
def dispose(self):
if self._delegate is not None:
log.debug('dispose %s.%r', self._delegate.__module__, self._delegate)
self._delegate.dispose()
@property
def engine(self):
return self._delegate
@engine.setter
def engine(self, engine):
if engine is None:
prefix = ''
else:
assert engine.url.drivername == 'sqlite'
prefix = f'{engine.__module__}.'
self.dispose()
log.debug('set engine of %r to %s%r', self, prefix, engine)
self._delegate = engine
@property
def url(self):
return self.engine.url if self.engine is not None else None
@url.setter
def url(self, url):
self._create_engine(url)
def __repr__(self):
if self.engine is None:
return super().__repr__()
return (f'<{self.__module__}.{self.__class__.__name__}'
f' url={str(self.url)!r}>')
class SQLiteEngineProxy(EngineProxy):
memory_write_path = None
@property
def file(self):
if self.url is None or self.url.database is None:
return None
return _tools.path_from_filename(self.url.database)
@file.setter
def file(self, filename):
url = 'sqlite://'
if filename is not None:
url += f'/{filename}'
self.url = url
def __repr__(self):
if self.file is None:
return super().__repr__()
parent = ''
name = self.file.as_posix()
if self.file.is_absolute():
parent = f' parent={self.file.parent.name!r}'
name = self.file.name
return (f'<{self.__module__}.{self.__class__.__name__}'
f' filename={name!r}{parent}'
f' size={self.file_size()!r}>')
def file_with_suffix(self, suffix):
if self.file is None:
name = f'{self.memory_write_path.name}{suffix}'
return self.memory_write_path.with_name(name)
return self.file.with_suffix(suffix)
def file_exists(self):
return self.file is not None and self.file.exists()
def file_mtime(self):
return (datetime.datetime.fromtimestamp(self.file.stat().st_mtime)
if self.file_exists() else None)
def file_size(self, as_megabytes=False):
if self.file_exists():
result = self.file.stat().st_size
if as_megabytes:
result /= 2**20
return result
return None
def file_sha256(self):
return _tools.sha256sum(self.file) if self.file_exists() else None