Version 3.2 of the decorator module

1 files changed, 172 insertions, 0 deletions

diff --git a/src/decorator.py b/src/decorator.py
new file mode 100644
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+++ b/src/decorator.py
@@ -0,0 +1,172 @@
+##########################     LICENCE     ###############################
+##
+##   Copyright (c) 2005, Michele Simionato
+##   All rights reserved.
+##
+##   Redistributions of source code must retain the above copyright 
+##   notice, this list of conditions and the following disclaimer.
+##   Redistributions in bytecode form must reproduce the above copyright
+##   notice, this list of conditions and the following disclaimer in
+##   the documentation and/or other materials provided with the
+##   distribution. 
+
+##   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+##   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+##   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+##   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+##   HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+##   INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+##   BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+##   OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+##   ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
+##   TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
+##   USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+##   DAMAGE.
+
+"""
+Decorator module, see http://pypi.python.org/pypi/decorator
+for the documentation.
+"""
+
+__version__ = '3.2.0'
+
+__all__ = ["decorator", "FunctionMaker", "partial"]
+
+import os, sys, re, inspect, string, warnings
+
+try:
+    from functools import partial
+except ImportError: # for Python version < 2.5
+    class partial(object):
+        "A simple replacement of functools.partial"
+        def __init__(self, func, *args, **kw):
+            self.func = func
+            self.args = args                
+            self.keywords = kw
+        def __call__(self, *otherargs, **otherkw):
+            kw = self.keywords.copy()
+            kw.update(otherkw)
+            return self.func(*(self.args + otherargs), **kw)
+
+DEF = re.compile('\s*def\s*([_\w][_\w\d]*)\s*\(')
+
+# basic functionality
+class FunctionMaker(object):
+    """
+    An object with the ability to create functions with a given signature.
+    It has attributes name, doc, module, signature, defaults, dict and
+    methods update and make.
+    """
+    def __init__(self, func=None, name=None, signature=None,
+                 defaults=None, doc=None, module=None, funcdict=None):
+        if func:
+            # func can be a class or a callable, but not an instance method
+            self.name = func.__name__
+            if self.name == '<lambda>': # small hack for lambda functions
+                self.name = '_lambda_' 
+            self.doc = func.__doc__
+            self.module = func.__module__
+            if inspect.isfunction(func):
+                argspec = inspect.getargspec(func)
+                self.args, self.varargs, self.keywords, self.defaults = argspec
+                for i, arg in enumerate(self.args):
+                    setattr(self, 'arg%d' % i, arg)
+                self.signature = inspect.formatargspec(
+                    formatvalue=lambda val: "", *argspec)[1:-1]
+                self.dict = func.__dict__.copy()
+        if name:
+            self.name = name
+        if signature is not None:
+            self.signature = signature
+        if defaults:
+            self.defaults = defaults
+        if doc:
+            self.doc = doc
+        if module:
+            self.module = module
+        if funcdict:
+            self.dict = funcdict
+        # check existence required attributes
+        assert hasattr(self, 'name')
+        if not hasattr(self, 'signature'):
+            raise TypeError('You are decorating a non function: %s' % func)
+
+    def update(self, func, **kw):
+        "Update the signature of func with the data in self"
+        func.__name__ = self.name
+        func.__doc__ = getattr(self, 'doc', None)
+        func.__dict__ = getattr(self, 'dict', {})
+        func.func_defaults = getattr(self, 'defaults', ())
+        callermodule = sys._getframe(3).f_globals.get('__name__', '?')
+        func.__module__ = getattr(self, 'module', callermodule)
+        func.__dict__.update(kw)
+
+    def make(self, src_templ, evaldict=None, addsource=False, **attrs):
+        "Make a new function from a given template and update the signature"
+        src = src_templ % vars(self) # expand name and signature
+        evaldict = evaldict or {}
+        mo = DEF.match(src)
+        if mo is None:
+            raise SyntaxError('not a valid function template\n%s' % src)
+        name = mo.group(1) # extract the function name
+        reserved_names = set([name] + [
+            arg.strip(' *') for arg in self.signature.split(',')])
+        for n, v in evaldict.iteritems():
+            if n in reserved_names:
+                raise NameError('%s is overridden in\n%s' % (n, src))
+        if not src.endswith('\n'): # add a newline just for safety
+            src += '\n'
+        try:
+            code = compile(src, '<string>', 'single')
+            exec code in evaldict
+        except:
+            print >> sys.stderr, 'Error in generated code:'
+            print >> sys.stderr, src
+            raise
+        func = evaldict[name]
+        if addsource:
+            attrs['__source__'] = src
+        self.update(func, **attrs)
+        return func
+
+    @classmethod
+    def create(cls, obj, body, evaldict, defaults=None,
+               doc=None, module=None, addsource=True,**attrs):
+        """
+        Create a function from the strings name, signature and body.
+        evaldict is the evaluation dictionary. If addsource is true an attribute
+        __source__ is added to the result. The attributes attrs are added,
+        if any.
+        """
+        if isinstance(obj, str): # "name(signature)"
+            name, rest = obj.strip().split('(', 1)
+            signature = rest[:-1] #strip a right parens            
+            func = None
+        else: # a function
+            name = None
+            signature = None
+            func = obj
+        fun = cls(func, name, signature, defaults, doc, module)
+        ibody = '\n'.join('    ' + line for line in body.splitlines())
+        return fun.make('def %(name)s(%(signature)s):\n' + ibody, 
+                        evaldict, addsource, **attrs)
+  
+def decorator(caller, func=None):
+    """
+    decorator(caller) converts a caller function into a decorator;
+    decorator(caller, func) decorates a function using a caller.
+    """
+    if func is not None: # returns a decorated function
+        return FunctionMaker.create(
+            func, "return _call_(_func_, %(signature)s)",
+            dict(_call_=caller, _func_=func), undecorated=func)
+    else: # returns a decorator
+        if isinstance(caller, partial):
+            return partial(decorator, caller)
+        # otherwise assume caller is a function
+        f = inspect.getargspec(caller)[0][0] # first arg
+        return FunctionMaker.create(
+            '%s(%s)' % (caller.__name__, f), 
+            'return decorator(_call_, %s)' % f,
+            dict(_call_=caller, decorator=decorator), undecorated=caller,
+            doc=caller.__doc__, module=caller.__module__)