Fixed database typo and removed unnecessary class identifier.

venv/Lib/site-packages/imageio/core/findlib.py

@@ -0,0 +1,161 @@
+# -*- coding: utf-8 -*-
+# Copyright (c) 2015-1018, imageio contributors
+# Copyright (C) 2013, Zach Pincus, Almar Klein and others
+
+""" This module contains generic code to find and load a dynamic library.
+"""
+
+import os
+import sys
+import ctypes
+
+
+LOCALDIR = os.path.abspath(os.path.dirname(__file__))
+
+# Flag that can be patched / set to True to disable loading non-system libs
+SYSTEM_LIBS_ONLY = False
+
+
+def looks_lib(fname):
+    """ Returns True if the given filename looks like a dynamic library.
+    Based on extension, but cross-platform and more flexible.
+    """
+    fname = fname.lower()
+    if sys.platform.startswith("win"):
+        return fname.endswith(".dll")
+    elif sys.platform.startswith("darwin"):
+        return fname.endswith(".dylib")
+    else:
+        return fname.endswith(".so") or ".so." in fname
+
+
+def generate_candidate_libs(lib_names, lib_dirs=None):
+    """ Generate a list of candidate filenames of what might be the dynamic
+    library corresponding with the given list of names.
+    Returns (lib_dirs, lib_paths)
+    """
+    lib_dirs = lib_dirs or []
+
+    # Get system dirs to search
+    sys_lib_dirs = [
+        "/lib",
+        "/usr/lib",
+        "/usr/lib/x86_64-linux-gnu",
+        "/usr/lib/aarch64-linux-gnu",
+        "/usr/local/lib",
+        "/opt/local/lib",
+    ]
+
+    # Get Python dirs to search (shared if for Pyzo)
+    py_sub_dirs = ["lib", "DLLs", "Library/bin", "shared"]
+    py_lib_dirs = [os.path.join(sys.prefix, d) for d in py_sub_dirs]
+    if hasattr(sys, "base_prefix"):
+        py_lib_dirs += [os.path.join(sys.base_prefix, d) for d in py_sub_dirs]
+
+    # Get user dirs to search (i.e. HOME)
+    home_dir = os.path.expanduser("~")
+    user_lib_dirs = [os.path.join(home_dir, d) for d in ["lib"]]
+
+    # Select only the dirs for which a directory exists, and remove duplicates
+    potential_lib_dirs = lib_dirs + sys_lib_dirs + py_lib_dirs + user_lib_dirs
+    lib_dirs = []
+    for ld in potential_lib_dirs:
+        if os.path.isdir(ld) and ld not in lib_dirs:
+            lib_dirs.append(ld)
+
+    # Now attempt to find libraries of that name in the given directory
+    # (case-insensitive)
+    lib_paths = []
+    for lib_dir in lib_dirs:
+        # Get files, prefer short names, last version
+        files = os.listdir(lib_dir)
+        files = reversed(sorted(files))
+        files = sorted(files, key=len)
+        for lib_name in lib_names:
+            # Test all filenames for name and ext
+            for fname in files:
+                if fname.lower().startswith(lib_name) and looks_lib(fname):
+                    lib_paths.append(os.path.join(lib_dir, fname))
+
+    # Return (only the items which are files)
+    lib_paths = [lp for lp in lib_paths if os.path.isfile(lp)]
+    return lib_dirs, lib_paths
+
+
+def load_lib(exact_lib_names, lib_names, lib_dirs=None):
+    """ load_lib(exact_lib_names, lib_names, lib_dirs=None)
+
+    Load a dynamic library.
+
+    This function first tries to load the library from the given exact
+    names. When that fails, it tries to find the library in common
+    locations. It searches for files that start with one of the names
+    given in lib_names (case insensitive). The search is performed in
+    the given lib_dirs and a set of common library dirs.
+
+    Returns ``(ctypes_library, library_path)``
+    """
+
+    # Checks
+    assert isinstance(exact_lib_names, list)
+    assert isinstance(lib_names, list)
+    if lib_dirs is not None:
+        assert isinstance(lib_dirs, list)
+    exact_lib_names = [n for n in exact_lib_names if n]
+    lib_names = [n for n in lib_names if n]
+
+    # Get reference name (for better messages)
+    if lib_names:
+        the_lib_name = lib_names[0]
+    elif exact_lib_names:
+        the_lib_name = exact_lib_names[0]
+    else:
+        raise ValueError("No library name given.")
+
+    # Collect filenames of potential libraries
+    # First try a few bare library names that ctypes might be able to find
+    # in the default locations for each platform.
+    if SYSTEM_LIBS_ONLY:
+        lib_dirs, lib_paths = [], []
+    else:
+        lib_dirs, lib_paths = generate_candidate_libs(lib_names, lib_dirs)
+    lib_paths = exact_lib_names + lib_paths
+
+    # Select loader
+    if sys.platform.startswith("win"):
+        loader = ctypes.windll
+    else:
+        loader = ctypes.cdll
+
+    # Try to load until success
+    the_lib = None
+    errors = []
+    for fname in lib_paths:
+        try:
+            the_lib = loader.LoadLibrary(fname)
+            break
+        except Exception as err:
+            # Don't record errors when it couldn't load the library from an
+            # exact name -- this fails often, and doesn't provide any useful
+            # debugging information anyway, beyond "couldn't find library..."
+            if fname not in exact_lib_names:
+                errors.append((fname, err))
+
+    # No success ...
+    if the_lib is None:
+        if errors:
+            # No library loaded, and load-errors reported for some
+            # candidate libs
+            err_txt = ["%s:\n%s" % (l, str(e)) for l, e in errors]
+            msg = (
+                "One or more %s libraries were found, but "
+                + "could not be loaded due to the following errors:\n%s"
+            )
+            raise OSError(msg % (the_lib_name, "\n\n".join(err_txt)))
+        else:
+            # No errors, because no potential libraries found at all!
+            msg = "Could not find a %s library in any of:\n%s"
+            raise OSError(msg % (the_lib_name, "\n".join(lib_dirs)))
+
+    # Done
+    return the_lib, fname