Merge pull request #4342 from abhinav-upadhyay/unnessary-variable-assignment

Return value directly from the try block and avoid a variable

IPython/lib/deepreload.py

@@ -1,338 +1,337 b''
 # -*- coding: utf-8 -*-
 """
 A module to change reload() so that it acts recursively.
 To enable it type::
 
     import __builtin__, deepreload
     __builtin__.reload = deepreload.reload
 
 You can then disable it with::
 
     __builtin__.reload = deepreload.original_reload
 
 Alternatively, you can add a dreload builtin alongside normal reload with::
 
     __builtin__.dreload = deepreload.reload
 
 This code is almost entirely based on knee.py, which is a Python
 re-implementation of hierarchical module import.
 """
 #*****************************************************************************
 #       Copyright (C) 2001 Nathaniel Gray <[e-mail]>
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #*****************************************************************************
 
 import __builtin__
 from contextlib import contextmanager
 import imp
 import sys
 
 from types import ModuleType
 from warnings import warn
 
 original_import = __builtin__.__import__
 
 @contextmanager
 def replace_import_hook(new_import):
     saved_import = __builtin__.__import__
     __builtin__.__import__ = new_import
     try:
         yield
     finally:
         __builtin__.__import__ = saved_import
 
 def get_parent(globals, level):
     """
     parent, name = get_parent(globals, level)
 
     Return the package that an import is being performed in.  If globals comes
     from the module foo.bar.bat (not itself a package), this returns the
     sys.modules entry for foo.bar.  If globals is from a package's __init__.py,
     the package's entry in sys.modules is returned.
 
     If globals doesn't come from a package or a module in a package, or a
     corresponding entry is not found in sys.modules, None is returned.
     """
     orig_level = level
 
     if not level or not isinstance(globals, dict):
         return None, ''
 
     pkgname = globals.get('__package__', None)
 
     if pkgname is not None:
         # __package__ is set, so use it
         if not hasattr(pkgname, 'rindex'):
             raise ValueError('__package__ set to non-string')
         if len(pkgname) == 0:
             if level > 0:
                 raise ValueError('Attempted relative import in non-package')
             return None, ''
         name = pkgname
     else:
         # __package__ not set, so figure it out and set it
         if '__name__' not in globals:
             return None, ''
         modname = globals['__name__']
 
         if '__path__' in globals:
             # __path__ is set, so modname is already the package name
             globals['__package__'] = name = modname
         else:
             # Normal module, so work out the package name if any
             lastdot = modname.rfind('.')
             if lastdot < 0 and level > 0:
                 raise ValueError("Attempted relative import in non-package")
             if lastdot < 0:
                 globals['__package__'] = None
                 return None, ''
             globals['__package__'] = name = modname[:lastdot]
 
     dot = len(name)
     for x in xrange(level, 1, -1):
         try:
             dot = name.rindex('.', 0, dot)
         except ValueError:
             raise ValueError("attempted relative import beyond top-level "
                              "package")
     name = name[:dot]
 
     try:
         parent = sys.modules[name]
     except:
         if orig_level < 1:
             warn("Parent module '%.200s' not found while handling absolute "
                  "import" % name)
             parent = None
         else:
             raise SystemError("Parent module '%.200s' not loaded, cannot "
                               "perform relative import" % name)
 
     # We expect, but can't guarantee, if parent != None, that:
     # - parent.__name__ == name
     # - parent.__dict__ is globals
     # If this is violated...  Who cares?
     return parent, name
 
 def load_next(mod, altmod, name, buf):
     """
     mod, name, buf = load_next(mod, altmod, name, buf)
 
     altmod is either None or same as mod
     """
 
     if len(name) == 0:
         # completely empty module name should only happen in
         # 'from . import' (or '__import__("")')
         return mod, None, buf
 
     dot = name.find('.')
     if dot == 0:
         raise ValueError('Empty module name')
 
     if dot < 0:
         subname = name
         next = None
     else:
         subname = name[:dot]
         next = name[dot+1:]
 
     if buf != '':
         buf += '.'
     buf += subname
 
     result = import_submodule(mod, subname, buf)
     if result is None and mod != altmod:
         result = import_submodule(altmod, subname, subname)
         if result is not None:
             buf = subname
 
     if result is None:
         raise ImportError("No module named %.200s" % name)
 
     return result, next, buf
 
 # Need to keep track of what we've already reloaded to prevent cyclic evil
 found_now = {}
 
 def import_submodule(mod, subname, fullname):
     """m = import_submodule(mod, subname, fullname)"""
     # Require:
     # if mod == None: subname == fullname
     # else: mod.__name__ + "." + subname == fullname
 
     global found_now
     if fullname in found_now and fullname in sys.modules:
         m = sys.modules[fullname]
     else:
         print 'Reloading', fullname
         found_now[fullname] = 1
         oldm = sys.modules.get(fullname, None)
 
         if mod is None:
             path = None
         elif hasattr(mod, '__path__'):
             path = mod.__path__
         else:
             return None
 
         try:
             # This appears to be necessary on Python 3, because imp.find_module()
             # tries to import standard libraries (like io) itself, and we don't
             # want them to be processed by our deep_import_hook.
             with replace_import_hook(original_import):
                 fp, filename, stuff = imp.find_module(subname, path)
         except ImportError:
             return None
 
         try:
             m = imp.load_module(fullname, fp, filename, stuff)
         except:
             # load_module probably removed name from modules because of
             # the error.  Put back the original module object.
             if oldm:
                 sys.modules[fullname] = oldm
             raise
         finally:
             if fp: fp.close()
 
         add_submodule(mod, m, fullname, subname)
 
     return m
 
 def add_submodule(mod, submod, fullname, subname):
     """mod.{subname} = submod"""
     if mod is None:
         return #Nothing to do here.
 
     if submod is None:
         submod = sys.modules[fullname]
 
     setattr(mod, subname, submod)
 
     return
 
 def ensure_fromlist(mod, fromlist, buf, recursive):
     """Handle 'from module import a, b, c' imports."""
     if not hasattr(mod, '__path__'):
         return
     for item in fromlist:
         if not hasattr(item, 'rindex'):
             raise TypeError("Item in ``from list'' not a string")
         if item == '*':
             if recursive:
                 continue # avoid endless recursion
             try:
                 all = mod.__all__
             except AttributeError:
                 pass
             else:
                 ret = ensure_fromlist(mod, all, buf, 1)
                 if not ret:
                     return 0
         elif not hasattr(mod, item):
             import_submodule(mod, item, buf + '.' + item)
 
 def deep_import_hook(name, globals=None, locals=None, fromlist=None, level=-1):
     """Replacement for __import__()"""
     parent, buf = get_parent(globals, level)
 
     head, name, buf = load_next(parent, None if level < 0 else parent, name, buf)
 
     tail = head
     while name:
         tail, name, buf = load_next(tail, tail, name, buf)
 
     # If tail is None, both get_parent and load_next found
     # an empty module name: someone called __import__("") or
     # doctored faulty bytecode
     if tail is None:
         raise ValueError('Empty module name')
 
     if not fromlist:
         return head
 
     ensure_fromlist(tail, fromlist, buf, 0)
     return tail
 
 modules_reloading = {}
 
 def deep_reload_hook(m):
     """Replacement for reload()."""
     if not isinstance(m, ModuleType):
         raise TypeError("reload() argument must be module")
 
     name = m.__name__
 
     if name not in sys.modules:
         raise ImportError("reload(): module %.200s not in sys.modules" % name)
 
     global modules_reloading
     try:
         return modules_reloading[name]
     except:
         modules_reloading[name] = m
 
     dot = name.rfind('.')
     if dot < 0:
         subname = name
         path = None
     else:
         try:
             parent = sys.modules[name[:dot]]
         except KeyError:
             modules_reloading.clear()
             raise ImportError("reload(): parent %.200s not in sys.modules" % name[:dot])
         subname = name[dot+1:]
         path = getattr(parent, "__path__", None)
 
     try:
         # This appears to be necessary on Python 3, because imp.find_module()
         # tries to import standard libraries (like io) itself, and we don't
         # want them to be processed by our deep_import_hook.
         with replace_import_hook(original_import):
             fp, filename, stuff  = imp.find_module(subname, path)
     finally:
         modules_reloading.clear()
 
     try:
         newm = imp.load_module(name, fp, filename, stuff)
     except:
          # load_module probably removed name from modules because of
          # the error.  Put back the original module object.
         sys.modules[name] = m
         raise
     finally:
         if fp: fp.close()
 
     modules_reloading.clear()
     return newm
 
 # Save the original hooks
 try:
     original_reload = __builtin__.reload
 except AttributeError:
     original_reload = imp.reload    # Python 3
 
 # Replacement for reload()
 def reload(module, exclude=['sys', 'os.path', '__builtin__', '__main__']):
     """Recursively reload all modules used in the given module.  Optionally
     takes a list of modules to exclude from reloading.  The default exclude
     list contains sys, __main__, and __builtin__, to prevent, e.g., resetting
     display, exception, and io hooks.
     """
     global found_now
     for i in exclude:
         found_now[i] = 1
     try:
         with replace_import_hook(deep_import_hook):
-            ret = deep_reload_hook(module)
+            return deep_reload_hook(module)
     finally:
         found_now = {}
-    return ret
 
 # Uncomment the following to automatically activate deep reloading whenever
 # this module is imported
 #__builtin__.reload = reload

IPython/lib/latextools.py

@@ -1,252 +1,251 b''
 # -*- coding: utf-8 -*-
 """Tools for handling LaTeX.
 
 Authors:
 
 * Brian Granger
 """
 #-----------------------------------------------------------------------------
 # Copyright (C) 2010 IPython Development Team.
 #
 # Distributed under the terms of the Modified BSD License.
 #
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 from io import BytesIO
 from base64 import encodestring
 import os
 import tempfile
 import shutil
 import subprocess
 
 from IPython.utils.process import find_cmd, FindCmdError
 from IPython.config.configurable import SingletonConfigurable
 from IPython.utils.traitlets import List, CBool, CUnicode
 from IPython.utils.py3compat import bytes_to_str
 
 #-----------------------------------------------------------------------------
 # Tools
 #-----------------------------------------------------------------------------
 
 
 class LaTeXTool(SingletonConfigurable):
     """An object to store configuration of the LaTeX tool."""
 
     backends = List(
         CUnicode, ["matplotlib", "dvipng"],
         help="Preferred backend to draw LaTeX math equations. "
         "Backends in the list are checked one by one and the first "
         "usable one is used.  Note that `matplotlib` backend "
         "is usable only for inline style equations.  To draw  "
         "display style equations, `dvipng` backend must be specified. ",
         # It is a List instead of Enum, to make configuration more
         # flexible.  For example, to use matplotlib mainly but dvipng
         # for display style, the default ["matplotlib", "dvipng"] can
         # be used.  To NOT use dvipng so that other repr such as
         # unicode pretty printing is used, you can use ["matplotlib"].
         config=True)
 
     use_breqn = CBool(
         True,
         help="Use breqn.sty to automatically break long equations. "
         "This configuration takes effect only for dvipng backend.",
         config=True)
 
     packages = List(
         ['amsmath', 'amsthm', 'amssymb', 'bm'],
         help="A list of packages to use for dvipng backend. "
         "'breqn' will be automatically appended when use_breqn=True.",
         config=True)
 
     preamble = CUnicode(
         help="Additional preamble to use when generating LaTeX source "
         "for dvipng backend.",
         config=True)
 
 
 def latex_to_png(s, encode=False, backend=None, wrap=False):
     """Render a LaTeX string to PNG.
 
     Parameters
     ----------
     s : str
         The raw string containing valid inline LaTeX.
     encode : bool, optional
         Should the PNG data bebase64 encoded to make it JSON'able.
     backend : {matplotlib, dvipng}
         Backend for producing PNG data.
     wrap : bool
         If true, Automatically wrap `s` as a LaTeX equation.
 
     None is returned when the backend cannot be used.
 
     """
     allowed_backends = LaTeXTool.instance().backends
     if backend is None:
         backend = allowed_backends[0]
     if backend not in allowed_backends:
         return None
     if backend == 'matplotlib':
         f = latex_to_png_mpl
     elif backend == 'dvipng':
         f = latex_to_png_dvipng
     else:
         raise ValueError('No such backend {0}'.format(backend))
     bin_data = f(s, wrap)
     if encode and bin_data:
         bin_data = encodestring(bin_data)
     return bin_data
 
 
 def latex_to_png_mpl(s, wrap):
     try:
         from matplotlib import mathtext
     except ImportError:
         return None
 
     if wrap:
         s = '${0}$'.format(s)
     mt = mathtext.MathTextParser('bitmap')
     f = BytesIO()
     mt.to_png(f, s, fontsize=12)
     return f.getvalue()
 
 
 def latex_to_png_dvipng(s, wrap):
     try:
         find_cmd('latex')
         find_cmd('dvipng')
     except FindCmdError:
         return None
     try:
         workdir = tempfile.mkdtemp()
         tmpfile = os.path.join(workdir, "tmp.tex")
         dvifile = os.path.join(workdir, "tmp.dvi")
         outfile = os.path.join(workdir, "tmp.png")
 
         with open(tmpfile, "w") as f:
             f.writelines(genelatex(s, wrap))
 
         with open(os.devnull, 'w') as devnull:
             subprocess.check_call(
                 ["latex", "-halt-on-error", tmpfile], cwd=workdir,
                 stdout=devnull, stderr=devnull)
 
             subprocess.check_call(
                 ["dvipng", "-T", "tight", "-x", "1500", "-z", "9",
                  "-bg", "transparent", "-o", outfile, dvifile], cwd=workdir,
                 stdout=devnull, stderr=devnull)
 
         with open(outfile, "rb") as f:
-            bin_data = f.read()
+            return f.read()
     finally:
         shutil.rmtree(workdir)
-    return bin_data
 
 
 def kpsewhich(filename):
     """Invoke kpsewhich command with an argument `filename`."""
     try:
         find_cmd("kpsewhich")
         proc = subprocess.Popen(
             ["kpsewhich", filename],
             stdout=subprocess.PIPE, stderr=subprocess.PIPE)
         (stdout, stderr) = proc.communicate()
         return stdout.strip()
     except FindCmdError:
         pass
 
 
 def genelatex(body, wrap):
     """Generate LaTeX document for dvipng backend."""
     lt = LaTeXTool.instance()
     breqn = wrap and lt.use_breqn and kpsewhich("breqn.sty")
     yield r'\documentclass{article}'
     packages = lt.packages
     if breqn:
         packages = packages + ['breqn']
     for pack in packages:
         yield r'\usepackage{{{0}}}'.format(pack)
     yield r'\pagestyle{empty}'
     if lt.preamble:
         yield lt.preamble
     yield r'\begin{document}'
     if breqn:
         yield r'\begin{dmath*}'
         yield body
         yield r'\end{dmath*}'
     elif wrap:
         yield '$${0}$$'.format(body)
     else:
         yield body
     yield r'\end{document}'
 
 
 _data_uri_template_png = """<img src="data:image/png;base64,%s" alt=%s />"""
 
 def latex_to_html(s, alt='image'):
     """Render LaTeX to HTML with embedded PNG data using data URIs.
 
     Parameters
     ----------
     s : str
         The raw string containing valid inline LateX.
     alt : str
         The alt text to use for the HTML.
     """
     base64_data = bytes_to_str(latex_to_png(s, encode=True), 'ascii')
     if base64_data:
         return _data_uri_template_png  % (base64_data, alt)
 
 
 # From matplotlib, thanks to mdboom. Once this is in matplotlib releases, we
 # will remove.
 def math_to_image(s, filename_or_obj, prop=None, dpi=None, format=None):
     """
     Given a math expression, renders it in a closely-clipped bounding
     box to an image file.
 
     *s*
        A math expression.  The math portion should be enclosed in
        dollar signs.
 
     *filename_or_obj*
        A filepath or writable file-like object to write the image data
        to.
 
     *prop*
        If provided, a FontProperties() object describing the size and
        style of the text.
 
     *dpi*
        Override the output dpi, otherwise use the default associated
        with the output format.
 
     *format*
        The output format, eg. 'svg', 'pdf', 'ps' or 'png'.  If not
        provided, will be deduced from the filename.
     """
     from matplotlib import figure
     # backend_agg supports all of the core output formats
     from matplotlib.backends import backend_agg
     from matplotlib.font_manager import FontProperties
     from matplotlib.mathtext import MathTextParser
 
     if prop is None:
         prop = FontProperties()
 
     parser = MathTextParser('path')
     width, height, depth, _, _ = parser.parse(s, dpi=72, prop=prop)
 
     fig = figure.Figure(figsize=(width / 72.0, height / 72.0))
     fig.text(0, depth/height, s, fontproperties=prop)
     backend_agg.FigureCanvasAgg(fig)
     fig.savefig(filename_or_obj, dpi=dpi, format=format)
 
     return depth