Improve models structure

src/layoutparser/models/__init__.py

@@ -1,4 +1 @@
-from . import catalog as _UNUSED
-# A trick learned from
-# https://github.com/facebookresearch/detectron2/blob/62cf3a2b6840734d2717abdf96e2dd57ed6612a6/detectron2/checkpoint/__init__.py#L6
-from .layoutmodel import Detectron2LayoutModel
+from .detectron2.layoutmodel import Detectron2LayoutModel

src/layoutparser/models/base_catalog.py

@@ -0,0 +1,20 @@
+from iopath.common.file_io import HTTPURLHandler
+from iopath.common.file_io import PathManager as PathManagerBase
+
+# A trick learned from https://github.com/facebookresearch/detectron2/blob/65faeb4779e4c142484deeece18dc958c5c9ad18/detectron2/utils/file_io.py#L3
+
+
+class DropboxHandler(HTTPURLHandler):
+    """
+    Supports download and file check for dropbox links
+    """
+
+    def _get_supported_prefixes(self):
+        return ["https://www.dropbox.com"]
+
+    def _isfile(self, path):
+        return path in self.cache_map
+
+
+PathManager = PathManagerBase()
+PathManager.register_handler(DropboxHandler())

src/layoutparser/models/base_layoutmodel.py

@@ -0,0 +1,50 @@
+from abc import ABC, abstractmethod
+import os
+import importlib
+
+
+class BaseLayoutModel(ABC):
+
+    @property
+    @abstractmethod
+    def DETECTOR_NAME(self):
+        pass
+
+    @abstractmethod
+    def detect(self):
+        pass
+
+    # Add lazy loading mechanisms for layout models, refer to
+    # layoutparser.ocr.BaseOCRAgent
+    # TODO: Build a metaclass for lazy module loader
+    @property
+    @abstractmethod
+    def DEPENDENCIES(self):
+        """DEPENDENCIES lists all necessary dependencies for the class."""
+        pass
+
+    @property
+    @abstractmethod
+    def MODULES(self):
+        """MODULES instructs how to import these necessary libraries."""
+        pass
+
+    @classmethod
+    def _import_module(cls):
+        for m in cls.MODULES:
+            if importlib.util.find_spec(m["module_path"]):
+                setattr(
+                    cls, m["import_name"], importlib.import_module(m["module_path"])
+                )
+            else:
+                raise ModuleNotFoundError(
+                    f"\n "
+                    f"\nPlease install the following libraries to support the class {cls.__name__}:"
+                    f"\n    pip install {' '.join(cls.DEPENDENCIES)}"
+                    f"\n "
+                )
+
+    def __new__(cls, *args, **kwargs):
+
+        cls._import_module()
+        return super().__new__(cls)

src/layoutparser/models/detectron2/__init__.py

@@ -0,0 +1,4 @@
+from . import catalog as _UNUSED
+# A trick learned from
+# https://github.com/facebookresearch/detectron2/blob/62cf3a2b6840734d2717abdf96e2dd57ed6612a6/detectron2/checkpoint/__init__.py#L6
+from .layoutmodel import Detectron2LayoutModel

src/layoutparser/models/catalog.py → src/layoutparser/models/detectron2/catalog.py

@@ -1,7 +1,6 @@
-from iopath.common.file_io import PathHandler, PathManager, HTTPURLHandler
-from iopath.common.file_io import PathManager as PathManagerBase
+from iopath.common.file_io import PathHandler
 
-# A trick learned from https://github.com/facebookresearch/detectron2/blob/65faeb4779e4c142484deeece18dc958c5c9ad18/detectron2/utils/file_io.py#L3
+from ..base_catalog import PathManager
 
 MODEL_CATALOG = {
     "HJDataset": {
@@ -49,6 +48,7 @@
     },
 }
 
+# fmt: off
 LABEL_MAP_CATALOG = {
     "HJDataset": {
         1: "Page Frame",
@@ -59,7 +59,12 @@
         6: "Subtitle",
         7: "Other",
     },
-    "PubLayNet": {0: "Text", 1: "Title", 2: "List", 3: "Table", 4: "Figure"},
+    "PubLayNet": {
+        0: "Text", 
+        1: "Title", 
+        2: "List", 
+        3: "Table", 
+        4: "Figure"},
     "PrimaLayout": {
         1: "TextRegion",
         2: "ImageRegion",
@@ -77,34 +82,26 @@
         5: "Headline",
         6: "Advertisement",
     },
-    "TableBank": {0: "Table"},
+    "TableBank": {
+        0: "Table"
+    },
 }
+# fmt: on
 
 
-class DropboxHandler(HTTPURLHandler):
-    """
-    Supports download and file check for dropbox links
-    """
-
-    def _get_supported_prefixes(self):
-        return ["https://www.dropbox.com"]
-
-    def _isfile(self, path):
-        return path in self.cache_map
-
-
-class LayoutParserHandler(PathHandler):
+class LayoutParserDetectron2ModelHandler(PathHandler):
     """
     Resolve anything that's in LayoutParser model zoo.
     """
 
-    PREFIX = "lp://"
+    PREFIX = "lp://detectron2/"
 
     def _get_supported_prefixes(self):
         return [self.PREFIX]
 
     def _get_local_path(self, path, **kwargs):
         model_name = path[len(self.PREFIX) :]
+
         dataset_name, *model_name, data_type = model_name.split("/")
 
         if data_type == "weight":
@@ -119,6 +116,4 @@ def _open(self, path, mode="r", **kwargs):
         return PathManager.open(self._get_local_path(path), mode, **kwargs)
 
 
-PathManager = PathManagerBase()
-PathManager.register_handler(DropboxHandler())
-PathManager.register_handler(LayoutParserHandler())
+PathManager.register_handler(LayoutParserDetectron2ModelHandler())

src/layoutparser/models/layoutmodel.py → src/layoutparser/models/detectron2/layoutmodel.py

@@ -1,58 +1,14 @@
-from abc import ABC, abstractmethod
-import os
-import importlib
-
 from PIL import Image
 import numpy as np
 import torch
 
 from .catalog import PathManager, LABEL_MAP_CATALOG
-from ..elements import *
+from ..base_layoutmodel import BaseLayoutModel
+from ...elements import Rectangle, TextBlock, Layout
 
 __all__ = ["Detectron2LayoutModel"]
 
 
-class BaseLayoutModel(ABC):
-    @abstractmethod
-    def detect(self):
-        pass
-
-    # Add lazy loading mechanisms for layout models, refer to
-    # layoutparser.ocr.BaseOCRAgent
-    # TODO: Build a metaclass for lazy module loader
-    @property
-    @abstractmethod
-    def DEPENDENCIES(self):
-        """DEPENDENCIES lists all necessary dependencies for the class."""
-        pass
-
-    @property
-    @abstractmethod
-    def MODULES(self):
-        """MODULES instructs how to import these necessary libraries."""
-        pass
-
-    @classmethod
-    def _import_module(cls):
-        for m in cls.MODULES:
-            if importlib.util.find_spec(m["module_path"]):
-                setattr(
-                    cls, m["import_name"], importlib.import_module(m["module_path"])
-                )
-            else:
-                raise ModuleNotFoundError(
-                    f"\n "
-                    f"\nPlease install the following libraries to support the class {cls.__name__}:"
-                    f"\n    pip install {' '.join(cls.DEPENDENCIES)}"
-                    f"\n "
-                )
-
-    def __new__(cls, *args, **kwargs):
-
-        cls._import_module()
-        return super().__new__(cls)
-
-
 class Detectron2LayoutModel(BaseLayoutModel):
     """Create a Detectron2-based Layout Detection Model
 
@@ -93,6 +49,7 @@ class Detectron2LayoutModel(BaseLayoutModel):
         },
         {"import_name": "_config", "module_path": "detectron2.config"},
     ]
+    DETECTOR_NAME = "detectron2"
 
     def __init__(
         self,
@@ -111,18 +68,47 @@ def __init__(
             extra_config.extend(["MODEL.DEVICE", "cpu"])
 
         cfg = self._config.get_cfg()
+        config_path = self._reconstruct_path_with_detector_name(config_path)
         config_path = PathManager.get_local_path(config_path)
         cfg.merge_from_file(config_path)
         cfg.merge_from_list(extra_config)
 
         if model_path is not None:
+            model_path = self._reconstruct_path_with_detector_name(model_path)
             cfg.MODEL.WEIGHTS = model_path
         cfg.MODEL.DEVICE = "cuda" if torch.cuda.is_available() else "cpu"
         self.cfg = cfg
 
         self.label_map = label_map
         self._create_model()
 
+    def _reconstruct_path_with_detector_name(self, path: str) -> str:
+        """This function will add the detector name (detectron2) into the
+        lp model config path to get the "canonical" model name.
+
+        For example, for a given config_path `lp://HJDataset/faster_rcnn_R_50_FPN_3x/config`,
+        it will transform it into `lp://detectron2/HJDataset/faster_rcnn_R_50_FPN_3x/config`.
+        However, if the config_path already contains the detector name, we won't change it.
+
+        This function is a general step to support multiple backends in the layout-parser
+        library.
+
+        Args:
+            path (str): The given input path that might or might not contain the detector name.
+
+        Returns:
+            str: a modified path that contains the detector name.
+        """
+        if path.startswith("lp://"):  # TODO: Move "lp://" to a constant
+            model_name = path[len("lp://") :]
+            model_name_segments = model_name.split("/")
+            if (
+                len(model_name_segments) == 3
+                and "detectron2" not in model_name_segments
+            ):
+                return "lp://" + self.DETECTOR_NAME + "/" + path[len("lp://") :]
+        return path
+
     def gather_output(self, outputs):
 
         instance_pred = outputs["instances"].to("cpu")