<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>horizon.utils.memoized — Horizon 2012.2.3 documentation</title> <link rel="stylesheet" href="../../../_static/nature.css" type="text/css" /> <link rel="stylesheet" href="../../../_static/pygments.css" type="text/css" /> <link rel="stylesheet" href="../../../_static/tweaks.css" type="text/css" /> <script type="text/javascript"> var DOCUMENTATION_OPTIONS = { URL_ROOT: '../../../', VERSION: '2012.2.3', COLLAPSE_INDEX: false, FILE_SUFFIX: '.html', HAS_SOURCE: true }; </script> <script type="text/javascript" src="../../../_static/jquery.js"></script> <script type="text/javascript" src="../../../_static/underscore.js"></script> <script type="text/javascript" src="../../../_static/doctools.js"></script> <script type="text/javascript" src="../../../_static/jquery.tweet.js"></script> <link rel="top" title="Horizon 2012.2.3 documentation" href="../../../index.html" /> <link rel="up" title="horizon" href="../../horizon.html" /> </head> <body> <div id="header"> <h1 id="logo"><a href="http://www.openstack.org/">OpenStack</a></h1> <ul id="navigation"> <li><a href="http://www.openstack.org/" title="Go to the Home page" class="link">Home</a></li> <li><a href="http://www.openstack.org/projects/" title="Go to the OpenStack Projects page">Projects</a></li> <li><a href="http://www.openstack.org/user-stories/" title="Go to the User Stories page" class="link">User Stories</a></li> <li><a href="http://www.openstack.org/community/" title="Go to the Community page" class="link">Community</a></li> <li><a href="http://www.openstack.org/blog/" title="Go to the OpenStack Blog">Blog</a></li> <li><a href="http://wiki.openstack.org/" title="Go to the OpenStack Wiki">Wiki</a></li> <li><a href="http://docs.openstack.org/" title="Go to OpenStack Documentation" class="current">Documentation</a></li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body"> <h1>Source code for horizon.utils.memoized</h1><div class="highlight"><pre> <span class="c"># vim: tabstop=4 shiftwidth=4 softtabstop=4</span> <span class="c">#</span> <span class="c"># Copyright 2012 Nebula, Inc.</span> <span class="c">#</span> <span class="c"># Licensed under the Apache License, Version 2.0 (the "License"); you may</span> <span class="c"># not use this file except in compliance with the License. You may obtain</span> <span class="c"># a copy of the License at</span> <span class="c">#</span> <span class="c"># http://www.apache.org/licenses/LICENSE-2.0</span> <span class="c">#</span> <span class="c"># Unless required by applicable law or agreed to in writing, software</span> <span class="c"># distributed under the License is distributed on an "AS IS" BASIS, WITHOUT</span> <span class="c"># WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the</span> <span class="c"># License for the specific language governing permissions and limitations</span> <span class="c"># under the License.</span> <span class="kn">import</span> <span class="nn">functools</span> <div class="viewcode-block" id="memoized"><a class="viewcode-back" href="../../../sourcecode/horizon/horizon.utils.memoized.html#horizon.utils.memoized.memoized">[docs]</a><span class="k">class</span> <span class="nc">memoized</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span> <span class="sd">'''Decorator. Caches a function's return value each time it is called.</span> <span class="sd"> If called later with the same arguments, the cached value is returned</span> <span class="sd"> (not reevaluated).</span> <span class="sd"> '''</span> <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">func</span><span class="p">):</span> <span class="bp">self</span><span class="o">.</span><span class="n">func</span> <span class="o">=</span> <span class="n">func</span> <span class="bp">self</span><span class="o">.</span><span class="n">cache</span> <span class="o">=</span> <span class="p">{}</span> <span class="k">def</span> <span class="nf">__call__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">):</span> <span class="k">try</span><span class="p">:</span> <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">cache</span><span class="p">[</span><span class="n">args</span><span class="p">]</span> <span class="k">except</span> <span class="ne">KeyError</span><span class="p">:</span> <span class="n">value</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">func</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">)</span> <span class="bp">self</span><span class="o">.</span><span class="n">cache</span><span class="p">[</span><span class="n">args</span><span class="p">]</span> <span class="o">=</span> <span class="n">value</span> <span class="k">return</span> <span class="n">value</span> <span class="k">except</span> <span class="ne">TypeError</span><span class="p">:</span> <span class="c"># uncachable -- for instance, passing a list as an argument.</span> <span class="c"># Better to not cache than to blow up entirely.</span> <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">func</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">)</span> <span class="k">def</span> <span class="nf">__repr__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="sd">'''Return the function's docstring.'''</span> <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">func</span><span class="o">.</span><span class="n">__doc__</span> <span class="k">def</span> <span class="nf">__get__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">obj</span><span class="p">,</span> <span class="n">objtype</span><span class="p">):</span> <span class="sd">'''Support instance methods.'''</span> <span class="k">return</span> <span class="n">functools</span><span class="o">.</span><span class="n">partial</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">__call__</span><span class="p">,</span> <span class="n">obj</span><span class="p">)</span></div> </pre></div> </div> </div> </div> <div class="sphinxsidebar"> <div class="sphinxsidebarwrapper"> <div id="searchbox" style="display: none"> <h3>Quick search</h3> <form class="search" action="../../../search.html" method="get"> <input type="text" name="q" size="18" /> <input type="submit" value="Go" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> <p class="searchtip" style="font-size: 90%"> Enter search terms or a module, class or function name. </p> </div> <script type="text/javascript">$('#searchbox').show(0);</script> </div> </div> <div class="clearer"></div> </div> <div class="related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../../../genindex.html" title="General Index" accesskey="I">index</a></li> <li class="right" > <a href="../../../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li><a href="../../../index.html">Horizon 2012.2.3 documentation</a> »</li> <li><a href="../../index.html" >Module code</a> »</li> <li><a href="../../horizon.html" accesskey="U">horizon</a> »</li> </ul> </div> <div class="footer"> © Copyright 2012, OpenStack, LLC. 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