80 lines
2.2 KiB
Python
80 lines
2.2 KiB
Python
import json
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import os
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class PersistentDict(dict):
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"""Extended dict that writes its content to a file every time a value is changed"""
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def __init__(self, file_name, *args, **kwargs):
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"""initialization of the dict and of the required files"""
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super().__init__(*args, **kwargs)
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self.path = file_name
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self.last_action = ""
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if not os.path.exists(self.path):
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with open(self.path, "a") as f:
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f.write("{}")
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self.read_dict()
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## helper - functions
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def write_dict(self):
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with open(self.path, "w") as f:
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json.dump(self, f)
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self.last_action = "w"
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def read_dict(self):
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with open(self.path) as f:
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tmp = dict(json.load(f))
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for key in tmp:
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super().__setitem__(key, tmp[key])
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self.last_action = "r"
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## extended dictionary - logic
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def __setitem__(self, key, value):
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if self.last_action != "r":
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self.read_dict()
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# not sure if the step to read is necessary, but I'll keep it for safety
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super().__setitem__(key,value)
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self.write_dict() # writes 'self' to a json file.
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def __getitem__(self, key):
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if self.last_action != "r":
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self.read_dict()
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ret_val = super().__getitem__(key)
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if type(ret_val) == dict:
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ret_val = HookedDict(key, self, ret_val)
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return ret_val
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def clear(self):
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super().clear()
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self.write_dict()
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return {}
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class HookedDict(dict):
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"""helper class to detect writes to a child-dictionary and triger a write in PersistentDict"""
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def __init__(self, own_name, parent_dict, *args, **kwargs):
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super().__init__(*args, **kwargs)
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self.name = own_name
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self.parent = parent_dict
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def __setitem__(self, key, value):
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super().__setitem__(key, value)
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self.parent.__setitem__(self.name, self)
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def __getitem__(self, key):
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ret_val = super().__getitem__(key)
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if type(ret_val) == dict:
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ret_val = HookedDict(key, self, ret_val)
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return ret_val
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def pop(self, k, d=None):
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retvalue = super().pop(k, d)
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self.parent.__setitem__(self.name, self)
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return retvalue
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