load model library when using pyinstaller to build executable file in windows

Signed-off-by: NathanFu <nathan@appflowy.io>

Author: appflowy

gpt4all-bindings/python/gpt4all/_pyllmodel.py

@@ -5,6 +5,7 @@
 import platform
 import re
 import subprocess
+from pathlib import Path
 import sys
 import threading
 from enum import Enum
@@ -54,16 +55,45 @@
 
 
 def load_llmodel_library():
+    """
+    Loads the llmodel shared library based on the current operating system.
+
+    This function attempts to load the shared library using the appropriate file
+    extension for the operating system. It first tries to load the library with the
+    'lib' prefix (common for macOS, Linux, and MinGW on Windows). If the file is not
+    found and the operating system is Windows, it attempts to load the library without
+    the 'lib' prefix (common for MSVC on Windows).
+
+    Returns:
+        ctypes.CDLL: The loaded shared library.
+
+    Raises:
+        OSError: If the shared library cannot be found.
+    """
+    # Determine the appropriate file extension for the shared library based on the platform
     ext = {"Darwin": "dylib", "Linux": "so", "Windows": "dll"}[platform.system()]
 
+    # Define library names with and without the 'lib' prefix
+    library_name_with_lib_prefix = f"libllmodel.{ext}"
+    library_name_without_lib_prefix = "llmodel.dll"
+
+    # Handle PyInstaller frozen path
+    if getattr(sys, 'frozen', False):
+        # sys._MEIPASS is an attribute used by PyInstaller to refer to the
+        # directory where it extracts the bundled application and its
+        # dependencies when running a frozen (packaged) executable.
+        base_path = Path(sys._MEIPASS) / 'gpt4all' / 'llmodel_DO_NOT_MODIFY' / 'build'
+    else:
+        base_path = MODEL_LIB_PATH
+
     try:
-        # macOS, Linux, MinGW
-        lib = ctypes.CDLL(str(MODEL_LIB_PATH / f"libllmodel.{ext}"))
-    except FileNotFoundError:
-        if ext != 'dll':
+        # Attempt to load the shared library with the 'lib' prefix (common for macOS, Linux, and MinGW)
+        lib = ctypes.CDLL(str(base_path / library_name_with_lib_prefix))
+    except OSError:  # OSError is more general and includes FileNotFoundError
+        if ext != "dll":
             raise
-        # MSVC
-        lib = ctypes.CDLL(str(MODEL_LIB_PATH / "llmodel.dll"))
+        # For Windows (ext == 'dll'), attempt to load the shared library without the 'lib' prefix (common for MSVC)
+        lib = ctypes.CDLL(str(base_path / library_name_without_lib_prefix))
 
     return lib