Move lru_cache definitions to __init__ (#30)

Using the lru_cache decorators on class methods, the ones that have a reference to `self`,
will also cache self. So we move it to the __init__ of the class

(DIS-2913)

dissect/esedb/esedb.py

@@ -45,6 +45,8 @@ def __init__(self, fh: BinaryIO, impacket_compat: bool = False):
 
         self.catalog = Catalog(self, pgnoFDPMSO)
 
+        self.page = lru_cache(4096)(self.page)
+
     @cached_property
     def has_small_pages(self) -> bool:
         """Return whether this database has small pages (<= 8K)."""
@@ -82,7 +84,6 @@ def read_page(self, num: int) -> bytes:
 
         return buf
 
-    @lru_cache(maxsize=4096)
     def page(self, num: int) -> Page:
         """Get a logical page.
 

dissect/esedb/record.py

@@ -151,6 +151,9 @@ def __init__(self, table: Table, node: Node):
                 self._tagged_data_view = xmemoryview(tagged_field_data, "<I")
                 self._tagged_fields[first_tagged_field.identifier] = first_tagged_field
 
+        self._get_tag_field = lru_cache(4096)(self._get_tag_field)
+        self._find_tag_field_idx = lru_cache(4096)(self._find_tag_field_idx)
+
     def get(self, column: Column, raw: bool = False) -> RecordValue:
         """Retrieve the value for the specified column.
 
@@ -355,12 +358,10 @@ def _get_tagged(self, column: Column) -> Optional[bytes]:
 
         return tag_field, value
 
-    @lru_cache(4096)
     def _get_tag_field(self, idx: int) -> TagField:
         """Retrieve the :class:`TagField` at the given index in the ``TAGFLD`` array."""
         return TagField(self, self._tagged_data_view[idx])
 
-    @lru_cache(4096)
     def _find_tag_field_idx(self, identifier: int, is_derived: bool = False) -> Optional[TagField]:
         """Find a tag field by identifier and optional derived flag.