Locations with decorators

src/importer/decorators.py

@@ -0,0 +1,41 @@
+"""
+A decorator takes a callable A and returns a callable B that will override the name of A.
+A decorator with arguments returns a closure decorator having access to the arguments.
+
+Example usage for the location decorators:
+
+class MyClass():
+    @cached_property
+    @replaced_by_schema_key(key="source-location")
+    @replaced_by_path(override="/somewhere/that/doesnt/exist")
+    @replaced_by_path(override="/somewhere/that/exists")
+    def location(self):
+        return None
+"""
+
+from pathlib import Path
+from os import PathLike
+from functools import wraps
+
+def replaced_by_path(path: PathLike): # Decorator builder
+    """Replace the method's returned path with the override if the override exists on disk"""
+    def decorator(original_function): # Built decorator (closure)
+        @wraps(original_function)
+        def wrapper(*args, **kwargs): # func's override
+            p = Path(path).expanduser()
+            if p.exists(): return p
+            else: return original_function(*args, **kwargs)
+        return wrapper
+    return decorator
+
+def replaced_by_schema_key(key: str): # Decorator builder
+    """Replace the method's returned path with the path pointed by the key if it exists on disk"""
+    def decorator(original_function): # Built decorator (closure)
+        @wraps(original_function)
+        def wrapper(*args, **kwargs): # func's override
+            schema = args[0].win.schema
+            try: override = schema.get_string(key)
+            except Exception: return original_function(*args, **kwargs) 
+            else: return replaced_by_path(override)(*args, **kwargs)
+        return wrapper
+    return decorator

src/importer/location.py

@@ -1,35 +0,0 @@
-from dataclasses import dataclass
-from functools import cached_property
-from pathlib import Path
-from os import PathLike
-
-
-@dataclass
-class Location():
-    """Abstraction for a location that has multiple candidate paths"""
-
-    candidates: list[PathLike] = None
-    
-    def __init__(self, *candidates):
-        self.candidates = list()
-        self.candidates.extend(candidates)
-        return self
-
-    def add(self, canddiate):
-        """Add a candidate (last evaluated)"""
-        self.candidates.append(canddiate)
-        return self
-    
-    def add_override(self, candidate):
-        """Add a canddiate (first evaluated)"""
-        self.candidates.insert(0, candidate)
-        return self
-
-    @cached_property
-    def path(self):
-        """Chosen path depending on availability on the disk."""
-        for candidate in self.candidates:
-            p = Path(candidate).expanduser()
-            if p.exists: 
-                return p
-        return None

src/importer/source.py

@@ -27,7 +27,6 @@ class Source(Iterable):
     """Source of games. Can be a program location on disk with a config file that points to game for example"""
 
     win = None
-    schema_keys: dict
 
     name: str
     variant: str
@@ -36,11 +35,6 @@ class Source(Iterable):
     def __init__(self, win) -> None:
         super().__init__()
         self.win = win
-        self.__init_schema_keys__()
-
-    def __init_schema_keys__(self):
-        """Initialize schema keys needed by the source if necessary"""
-        raise NotImplementedError()
 
     @property
     def full_name(self):
@@ -62,8 +56,3 @@ class Source(Iterable):
     def __iter__(self):
         """Get the source's iterator, to use in for loops"""
         raise NotImplementedError()
-
-    def __init_locations__(self):
-        """Initialize locations needed by the source.
-        Extended and called by **final** children."""
-        raise NotImplementedError()

src/importer/sources/lutris_source.py

@@ -1,10 +1,9 @@
-from pathlib import Path
 from functools import cached_property
 from sqlite3 import connect
 
 from cartridges.game2 import Game
 from cartridges.importer.source import Source, SourceIterator
-from cartridges.importer.location import Location
+from cartridges.importer.decorators import replaced_by_schema_key, replaced_by_path
 
 
 class LutrisSourceIterator(SourceIterator):
@@ -73,50 +72,48 @@ class LutrisSource(Source):
     
     name = "Lutris"
     executable_format = "xdg-open lutris:rungameid/{game_id}"
-    schema_keys = {
-        "location": None,
-        "cache_location": None
-    }
+
+    location = None
+    cache_location = None
 
     def __init__(self, win) -> None:
         super().__init__(win)
-        self.location = Location()
-        self.cache_location = Location()
 
     def __iter__(self):
         return LutrisSourceIterator(source=self)
 
-    def __init_locations__(self):
-        super().__init_locations__()
-        self.location.add_override(self.win.schema.get_string(self.schema_keys["location"]))
-        self.cache_location.add_override(self.win.schema.get_string(self.schema_keys["cache_location"]))
-
 
 class LutrisNativeSource(LutrisSource):
     """Class representing an installation of Lutris using native packaging"""
 
     variant = "native"
-    schema_keys = {
-        "location": "lutris-location",
-        "cache_location": "lutris-cache-location"
-    }
 
-    def __init_locations__(self):
-        super().__init_locations__()
-        self.location.add("~/.local/share/lutris/")
-        self.cache_location.add("~/.local/share/lutris/covers")
+    @cached_property
+    @replaced_by_schema_key("lutris-location")
+    @replaced_by_path("~/.local/share/lutris/")
+    def location(self):
+        raise FileNotFoundError()
+
+    @cached_property
+    @replaced_by_schema_key("lutris-cache-location")
+    @replaced_by_path("~/.local/share/lutris/covers")
+    def cache_location(self):
+        raise FileNotFoundError()
 
 
 class LutrisFlatpakSource(LutrisSource):
     """Class representing an installation of Lutris using flatpak"""
 
     variant = "flatpak"
-    schema_keys = {
-        "location": "lutris-flatpak-location",
-        "cache_location": "lutris-flatpak-cache-location"
-    }
 
-    def __init_locations__(self):
-        super().__init_locations__()
-        self.location.add("~/.var/app/net.lutris.Lutris/data/lutris")
-        self.cache_location.add("~/.var/app/net.lutris.Lutris/data/lutris/covers")
+    @cached_property
+    @replaced_by_schema_key("lutris-flatpak-location")
+    @replaced_by_path("~/.var/app/net.lutris.Lutris/data/lutris")
+    def location(self):
+        raise FileNotFoundError()
+
+    @cached_property
+    @replaced_by_schema_key("lutris-flatpak-cache-location")
+    @replaced_by_path("~/.var/app/net.lutris.Lutris/data/lutris/covers")
+    def cache_location(self):
+        raise FileNotFoundError()