[legacy] move builder and registry to legacy (#4603)

colossalai/legacy/registry/registry.py

@@ -0,0 +1,82 @@
+#!/usr/bin/env python
+# -*- encoding: utf-8 -*-
+
+from types import ModuleType
+from typing import List
+
+
+class Registry:
+    """This is a registry class used to register classes and modules so that a universal
+    object builder can be enabled.
+
+    Args:
+        name (str): The name of the registry .
+        third_party_library (list, optional):
+            List of third party libraries which are used in the initialization of the register module.
+    """
+
+    def __init__(self, name: str, third_party_library: List[ModuleType] = None):
+        self._name = name
+        self._registry = dict()
+        self._third_party_lib = third_party_library
+
+    @property
+    def name(self):
+        return self._name
+
+    def register_module(self, module_class):
+        """Registers a module represented in `module_class`.
+
+        Args:
+            module_class (class): The module to be registered.
+        Returns:
+            class: The module to be registered, so as to use it normally if via importing.
+        Raises:
+            AssertionError: Raises an AssertionError if the module has already been registered before.
+        """
+        module_name = module_class.__name__
+        assert module_name not in self._registry, f"{module_name} not found in {self.name}"
+        self._registry[module_name] = module_class
+
+        # return so as to use it normally if via importing
+        return module_class
+
+    def get_module(self, module_name: str):
+        """Retrieves a module with name `module_name` and returns the module if it has
+        already been registered before.
+
+        Args:
+            module_name (str): The name of the module to be retrieved.
+        Returns:
+            :class:`object`: The retrieved module or None.
+        Raises:
+            NameError: Raises a NameError if the module to be retrieved has neither been
+            registered directly nor as third party modules before.
+        """
+        if module_name in self._registry:
+            return self._registry[module_name]
+        elif self._third_party_lib is not None:
+            for lib in self._third_party_lib:
+                if hasattr(lib, module_name):
+                    return getattr(lib, module_name)
+            raise NameError(f'Module {module_name} not found in the registry {self.name}')
+
+    def has(self, module_name: str):
+        """Searches for a module with name `module_name` and returns a boolean value indicating
+        whether the module has been registered directly or as third party modules before.
+
+        Args:
+            module_name (str): The name of the module to be searched for.
+        Returns:
+            bool: A boolean value indicating whether the module has been registered directly or
+            as third party modules before.
+        """
+        found_flag = module_name in self._registry
+
+        if self._third_party_lib:
+            for lib in self._third_party_lib:
+                if hasattr(lib, module_name):
+                    found_flag = True
+                    break
+
+        return found_flag