Split botogram.utils in multiple files

This will aid maintenance

Author: Pietro Albini

botogram/utils.py

@@ -0,0 +1,14 @@
+"""
+    botogram.utils
+    Utilities used by the rest of the code
+
+    Copyright (c) 2016 Pietro Albini <[email protected]>
+    Released under the MIT license
+"""
+
+# flake8: noqa
+
+from .deprecations import deprecated, DeprecatedAttributes, warn
+from .strings import strip_urls, usernames_in
+from .startup import get_language, configure_logger
+from .calls import wraps, CallLazyArgument, call

botogram/utils/__init__.py

@@ -0,0 +1,64 @@
+"""
+    botogram.utils.calls
+    Utilities for dynamic function args
+
+    Copyright (c) 2015-2016 Pietro Albini <[email protected]>
+    Released under the MIT license
+"""
+
+import inspect
+
+import functools
+
+
+def wraps(func):
+    """Update a wrapper function to looks like the wrapped one"""
+    # A custom implementation of functools.wraps is needed because we need some
+    # more metadata on the returned function
+    def updater(original):
+        # Here the original signature is needed in order to call the function
+        # with the right set of arguments in Bot._call
+        original_signature = inspect.signature(original)
+
+        updated = functools.update_wrapper(original, func)
+        updated._botogram_original_signature = original_signature
+        return updated
+    return updater
+
+
+class CallLazyArgument:
+    """A special argument which is loaded lazily"""
+
+    _botogram_call_lazy_argument = True
+
+    def __init__(self, loader):
+        self.loader = loader
+
+    def load(self):
+        return self.loader()
+
+
+def call(func, **available):
+    """Call a function with a dynamic set of arguments"""
+    # Get the correct function signature
+    # _botogram_original_signature contains the signature used before wrapping
+    # a function with @utils.wraps, so the arguments gets resolved correctly
+    if hasattr(func, "_botogram_original_signature"):
+        signature = func._botogram_original_signature
+    else:
+        signature = inspect.signature(func)
+
+    kwargs = {}
+    for name in signature.parameters:
+        if name not in available:
+            raise TypeError("botogram doesn't know what to provide for %s"
+                            % name)
+
+        # If the argument is lazily loaded wake him up
+        arg = available[name]
+        if hasattr(arg, "_botogram_call_lazy_argument"):
+            arg = arg.load()
+
+        kwargs[name] = arg
+
+    return func(**kwargs)

botogram/utils/calls.py

@@ -0,0 +1,74 @@
+"""
+    botogram.utils.warns
+    Utilities about warns and deprecations
+
+    Copyright (c) 2015-2016 Pietro Albini <[email protected]>
+    Released under the MIT license
+"""
+
+import sys
+import traceback
+
+import logbook
+
+
+warn_logger = logbook.Logger("botogram's code warnings")
+
+
+def _deprecated_message(name, removed_on, fix, back):
+    before = "%s will be removed in botogram %s." % (name, removed_on)
+    after = "Fix: %s" % fix
+    warn(back - 1, before, after)
+
+
+def deprecated(name, removed_on, fix, back=0):
+    """Mark a function as deprecated"""
+    def decorator(func):
+        def wrapper(*args, **kwargs):
+            _deprecated_message(name, removed_on, fix, -2 - back)
+            return func(*args, **kwargs)
+        return wrapper
+    return decorator
+
+
+class DeprecatedAttributes:
+    """Mark a class attribute as deprecated"""
+
+    _deprecated_ = {}
+
+    def __getattribute__(self, key):
+        def get(k):
+            return object.__getattribute__(self, k)
+
+        deprecated = get("_deprecated_")
+
+        if key in deprecated:
+            _deprecated_message(
+                get("__class__").__name__ + "." + key,
+                deprecated[key]["removed_on"],
+                deprecated[key]["fix"],
+                -2,
+            )
+            if "callback" in deprecated[key]:
+                return deprecated[key]["callback"]()
+
+        return object.__getattribute__(self, key)
+
+
+def warn(stack_pos, before_message, after_message=None):
+    """Issue a warning caused by user code"""
+    # This is a workaround for http://bugs.python.org/issue25108
+    # In Python 3.5.0, traceback.extract_stack returns an additional internal
+    # stack frame, which causes a lot of trouble around there.
+    if sys.version_info[:3] == (3, 5, 0):
+        stack_pos -= 1
+
+    frame = traceback.extract_stack()[stack_pos - 1]
+    at_message = "At: %s (line %s)" % (frame[0], frame[1])
+
+    warn_logger.warn(before_message)
+    if after_message is not None:
+        warn_logger.warn(at_message)
+        warn_logger.warn(after_message + "\n")
+    else:
+        warn_logger.warn(at_message + "\n")