jupyter

packages/python/yap_kernel/yap_ipython/utils/openpy.py

@@ -0,0 +1,121 @@
+"""
+Tools to open .py files as Unicode, using the encoding specified within the file,
+as per PEP 263.
+
+Much of the code is taken from the tokenize module in Python 3.2.
+"""
+
+import io
+from io import TextIOWrapper, BytesIO
+import re
+from tokenize import open, detect_encoding
+
+cookie_re = re.compile(r"coding[:=]\s*([-\w.]+)", re.UNICODE)
+cookie_comment_re = re.compile(r"^\s*#.*coding[:=]\s*([-\w.]+)", re.UNICODE)
+
+def source_to_unicode(txt, errors='replace', skip_encoding_cookie=True):
+    """Converts a bytes string with python source code to unicode.
+
+    Unicode strings are passed through unchanged. Byte strings are checked
+    for the python source file encoding cookie to determine encoding.
+    txt can be either a bytes buffer or a string containing the source
+    code.
+    """
+    if isinstance(txt, str):
+        return txt
+    if isinstance(txt, bytes):
+        buffer = BytesIO(txt)
+    else:
+        buffer = txt
+    try:
+        encoding, _ = detect_encoding(buffer.readline)
+    except SyntaxError:
+        encoding = "ascii"
+    buffer.seek(0)
+    text = TextIOWrapper(buffer, encoding, errors=errors, line_buffering=True)
+    text.mode = 'r'
+    if skip_encoding_cookie:
+        return u"".join(strip_encoding_cookie(text))
+    else:
+        return text.read()
+
+def strip_encoding_cookie(filelike):
+    """Generator to pull lines from a text-mode file, skipping the encoding
+    cookie if it is found in the first two lines.
+    """
+    it = iter(filelike)
+    try:
+        first = next(it)
+        if not cookie_comment_re.match(first):
+            yield first
+        second = next(it)
+        if not cookie_comment_re.match(second):
+            yield second
+    except StopIteration:
+        return
+    
+    for line in it:
+        yield line
+
+def read_py_file(filename, skip_encoding_cookie=True):
+    """Read a Python file, using the encoding declared inside the file.
+    
+    Parameters
+    ----------
+    filename : str
+      The path to the file to read.
+    skip_encoding_cookie : bool
+      If True (the default), and the encoding declaration is found in the first
+      two lines, that line will be excluded from the output - compiling a
+      unicode string with an encoding declaration is a SyntaxError in Python 2.
+    
+    Returns
+    -------
+    A unicode string containing the contents of the file.
+    """
+    with open(filename) as f:   # the open function defined in this module.
+        if skip_encoding_cookie:
+            return "".join(strip_encoding_cookie(f))
+        else:
+            return f.read()
+
+def read_py_url(url, errors='replace', skip_encoding_cookie=True):
+    """Read a Python file from a URL, using the encoding declared inside the file.
+    
+    Parameters
+    ----------
+    url : str
+      The URL from which to fetch the file.
+    errors : str
+      How to handle decoding errors in the file. Options are the same as for
+      bytes.decode(), but here 'replace' is the default.
+    skip_encoding_cookie : bool
+      If True (the default), and the encoding declaration is found in the first
+      two lines, that line will be excluded from the output - compiling a
+      unicode string with an encoding declaration is a SyntaxError in Python 2.
+    
+    Returns
+    -------
+    A unicode string containing the contents of the file.
+    """
+    # Deferred import for faster start
+    from urllib.request import urlopen 
+    response = urlopen(url)
+    buffer = io.BytesIO(response.read())
+    return source_to_unicode(buffer, errors, skip_encoding_cookie)
+
+def _list_readline(x):
+    """Given a list, returns a readline() function that returns the next element
+    with each call.
+    """
+    x = iter(x)
+    def readline():
+        return next(x)
+    return readline
+
+# Code for going between .py files and cached .pyc files ----------------------
+try: 
+    from importlib.util import source_from_cache, cache_from_source
+except ImportError :
+    ## deprecated since 3.4
+    from imp import source_from_cache, cache_from_source