initial commit

billinglayer/python/shapely/decorators.py

@@ -0,0 +1,82 @@
+import os
+from functools import wraps
+
+import numpy as np
+
+from . import lib
+from .errors import UnsupportedGEOSVersionError
+
+
+class requires_geos:
+    def __init__(self, version):
+        if version.count(".") != 2:
+            raise ValueError("Version must be <major>.<minor>.<patch> format")
+        self.version = tuple(int(x) for x in version.split("."))
+
+    def __call__(self, func):
+        is_compatible = lib.geos_version >= self.version
+        is_doc_build = os.environ.get("SPHINX_DOC_BUILD") == "1"  # set in docs/conf.py
+        if is_compatible and not is_doc_build:
+            return func  # return directly, do not change the docstring
+
+        msg = "'{}' requires at least GEOS {}.{}.{}.".format(
+            func.__name__, *self.version
+        )
+        if is_compatible:
+
+            @wraps(func)
+            def wrapped(*args, **kwargs):
+                return func(*args, **kwargs)
+
+        else:
+
+            @wraps(func)
+            def wrapped(*args, **kwargs):
+                raise UnsupportedGEOSVersionError(msg)
+
+        doc = wrapped.__doc__
+        if doc:
+            # Insert the message at the first double newline
+            position = doc.find("\n\n") + 2
+            # Figure out the indentation level
+            indent = 2
+            while True:
+                if doc[position + indent] == " ":
+                    indent += 1
+                else:
+                    break
+            wrapped.__doc__ = doc.replace(
+                "\n\n", "\n\n{}.. note:: {}\n\n".format(" " * indent, msg), 1
+            )
+
+        return wrapped
+
+
+def multithreading_enabled(func):
+    """Prepare multithreading by setting the writable flags of object type
+    ndarrays to False.
+
+    NB: multithreading also requires the GIL to be released, which is done in
+    the C extension (ufuncs.c)."""
+
+    @wraps(func)
+    def wrapped(*args, **kwargs):
+        array_args = [
+            arg for arg in args if isinstance(arg, np.ndarray) and arg.dtype == object
+        ] + [
+            arg
+            for name, arg in kwargs.items()
+            if name not in {"where", "out"}
+            and isinstance(arg, np.ndarray)
+            and arg.dtype == object
+        ]
+        old_flags = [arr.flags.writeable for arr in array_args]
+        try:
+            for arr in array_args:
+                arr.flags.writeable = False
+            return func(*args, **kwargs)
+        finally:
+            for arr, old_flag in zip(array_args, old_flags):
+                arr.flags.writeable = old_flag
+
+    return wrapped