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<head>
  <title>Class: CacheManager</title>
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<body>



    <div id="classHeader">
        <table class="header-table">
        <tr class="top-aligned-row">
          <td><strong>Class</strong></td>
          <td class="class-name-in-header">CacheManager</td>
        </tr>
        <tr class="top-aligned-row">
            <td><strong>In:</strong></td>
            <td>
                <a href="../files/lib/storage/cache_rb.html">
                lib/storage/cache.rb
                </a>
        <br />
            </td>
        </tr>

        <tr class="top-aligned-row">
            <td><strong>Parent:</strong></td>
            <td>
                Object
            </td>
        </tr>
        </table>
    </div>
  <!-- banner header -->

  <div id="bodyContent">



  <div id="contextContent">
    <div id="diagram">
      <map id="map" name="map">
  <area shape="rect" coords="5,5,96,53"      href="CacheStats.html" alt="CacheStats
" />
  <area shape="rect" coords="120,5,232,53"      href="CacheManager.html" alt="CacheManager
" />
  <area shape="rect" coords="256,5,347,53"      href="CacheEntry.html" alt="CacheEntry
" />
</map>
<img src="../dot/f_42.png" usemap="#map" border="0" alt="dot/f_42.png">
    </div>

    <div id="description">
      <p>
This class manages the cache. It is initialized by the <a
href="Store.html">Store</a> and front ends the database behind the <a
href="Store.html">Store</a>.
</p>

    </div>


   </div>

    <div id="method-list">
      <h3 class="section-bar">Methods</h3>

      <div class="name-list">
      <a href="#M000131">delete</a>&nbsp;&nbsp;
      <a href="#M000129">get</a>&nbsp;&nbsp;
      <a href="#M000128">hash</a>&nbsp;&nbsp;
      <a href="#M000127">inspect</a>&nbsp;&nbsp;
      <a href="#M000137">keys</a>&nbsp;&nbsp;
      <a href="#M000135">makenoswap</a>&nbsp;&nbsp;
      <a href="#M000136">makeswap</a>&nbsp;&nbsp;
      <a href="#M000132">mark</a>&nbsp;&nbsp;
      <a href="#M000126">new</a>&nbsp;&nbsp;
      <a href="#M000130">put</a>&nbsp;&nbsp;
      <a href="#M000138">stats</a>&nbsp;&nbsp;
      <a href="#M000133">sync</a>&nbsp;&nbsp;
      <a href="#M000134">sync_chain</a>&nbsp;&nbsp;
      </div>
    </div>

  </div>


    <!-- if includes -->

    <div id="section">





      


    <!-- if method_list -->
    <div id="methods">
      <h3 class="section-bar">Public Class methods</h3>

      <div id="method-M000126" class="method-detail">
        <a name="M000126"></a>

        <div class="method-heading">
          <a href="#M000126" class="method-signature">
          <span class="method-name">new</span><span class="method-args">(db)</span>
          </a>
        </div>
      
        <div class="method-description">
          <p><a class="source-toggle" href="#"
            onclick="toggleCode('M000126-source');return false;">[Source]</a></p>
          <div class="method-source-code" id="M000126-source">
<pre>
<span class="ruby-comment cmt"># File lib/storage/cache.rb, line 112</span>
  <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">initialize</span>(<span class="ruby-identifier">db</span>)
    <span class="ruby-ivar">@cwidth</span> = <span class="ruby-identifier">options</span>[<span class="ruby-value str">'cache_width'</span>]
    <span class="ruby-ivar">@cdepth</span> = <span class="ruby-identifier">options</span>[<span class="ruby-value str">'cache_depth'</span>]

    <span class="ruby-ivar">@db</span> =  <span class="ruby-identifier">db</span>
    <span class="ruby-ivar">@st</span> = <span class="ruby-constant">CacheStats</span>.<span class="ruby-identifier">new</span>

    <span class="ruby-ivar">@cache</span> = <span class="ruby-constant">Array</span>.<span class="ruby-identifier">new</span>(<span class="ruby-ivar">@cwidth</span>) {<span class="ruby-constant">Array</span>.<span class="ruby-identifier">new</span>}
    <span class="ruby-ivar">@cwidth</span>.<span class="ruby-identifier">times</span> <span class="ruby-keyword kw">do</span> <span class="ruby-operator">|</span><span class="ruby-identifier">i</span><span class="ruby-operator">|</span>
      <span class="ruby-ivar">@cdepth</span>.<span class="ruby-identifier">times</span> <span class="ruby-keyword kw">do</span> <span class="ruby-operator">|</span><span class="ruby-identifier">j</span><span class="ruby-operator">|</span>
        <span class="ruby-ivar">@cache</span>[<span class="ruby-identifier">i</span>] <span class="ruby-operator">&lt;&lt;</span> <span class="ruby-constant">CacheEntry</span>.<span class="ruby-identifier">new</span>
        <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:cache_size</span>)
      <span class="ruby-keyword kw">end</span>
    <span class="ruby-keyword kw">end</span>

  <span class="ruby-keyword kw">end</span>
</pre>
          </div>
        </div>
      </div>

      <h3 class="section-bar">Public Instance methods</h3>

      <div id="method-M000131" class="method-detail">
        <a name="M000131"></a>

        <div class="method-heading">
          <a href="#M000131" class="method-signature">
          <span class="method-name">delete</span><span class="method-args">(oid)</span>
          </a>
        </div>
      
        <div class="method-description">
          <p>
<a href="CacheManager.html#M000131">delete</a> an object
</p>
          <p><a class="source-toggle" href="#"
            onclick="toggleCode('M000131-source');return false;">[Source]</a></p>
          <div class="method-source-code" id="M000131-source">
<pre>
<span class="ruby-comment cmt"># File lib/storage/cache.rb, line 254</span>
  <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">delete</span>(<span class="ruby-identifier">oid</span>)
    <span class="ruby-keyword kw">return</span> <span class="ruby-keyword kw">nil</span> <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">oid</span>.<span class="ruby-identifier">nil?</span>
    <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:deletes</span>)
    <span class="ruby-identifier">hv</span> = <span class="ruby-identifier">hash</span>(<span class="ruby-identifier">oid</span>)

    <span class="ruby-comment cmt"># mark dead in cache
</span>
    <span class="ruby-ivar">@cache</span>[<span class="ruby-identifier">hv</span>].<span class="ruby-identifier">each</span> <span class="ruby-keyword kw">do</span> <span class="ruby-operator">|</span><span class="ruby-identifier">ce</span><span class="ruby-operator">|</span>
      <span class="ruby-keyword kw">next</span> <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">oid</span> <span class="ruby-operator">!=</span> <span class="ruby-identifier">oid</span>
      <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">mark_dead</span>
      <span class="ruby-keyword kw">break</span>
    <span class="ruby-keyword kw">end</span>
    <span class="ruby-comment cmt"># delete it from the database
</span>
    <span class="ruby-ivar">@db</span>.<span class="ruby-identifier">delete</span>(<span class="ruby-identifier">oid</span>.<span class="ruby-identifier">to_s</span>)
  <span class="ruby-keyword kw">end</span>
</pre>
          </div>
        </div>
      </div>

      <div id="method-M000129" class="method-detail">
        <a name="M000129"></a>

        <div class="method-heading">
          <a href="#M000129" class="method-signature">
          <span class="method-name">get</span><span class="method-args">(oid)</span>
          </a>
        </div>
      
        <div class="method-description">
          <p>
gets an object
</p>
<dl>
<dt><tt>oid</tt></dt><dd>- integer object id to retrieve

</dd>
<dt><tt>return</tt></dt><dd>- a reference to the object or nil if none exists

</dd>
</dl>
          <p><a class="source-toggle" href="#"
            onclick="toggleCode('M000129-source');return false;">[Source]</a></p>
          <div class="method-source-code" id="M000129-source">
<pre>
<span class="ruby-comment cmt"># File lib/storage/cache.rb, line 151</span>
  <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">get</span>(<span class="ruby-identifier">oid</span>)
    <span class="ruby-keyword kw">return</span> <span class="ruby-keyword kw">nil</span> <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">oid</span>.<span class="ruby-identifier">nil?</span>
    <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:reads</span>)
    <span class="ruby-identifier">hv</span> = <span class="ruby-identifier">hash</span>(<span class="ruby-identifier">oid</span>)

    <span class="ruby-comment cmt"># search the cache
</span>
    <span class="ruby-ivar">@cache</span>[<span class="ruby-identifier">hv</span>].<span class="ruby-identifier">each</span> <span class="ruby-keyword kw">do</span> <span class="ruby-operator">|</span><span class="ruby-identifier">ce</span><span class="ruby-operator">|</span>
      <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">oid</span> <span class="ruby-operator">==</span> <span class="ruby-identifier">oid</span>
        <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:cache_read_hits</span>)
        <span class="ruby-comment cmt"># need to try putting hot hit to the head of the list?
</span>
        <span class="ruby-keyword kw">return</span> <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">obj</span>
      <span class="ruby-keyword kw">end</span>
    <span class="ruby-keyword kw">end</span>

    <span class="ruby-comment cmt"># cache miss - search the database
</span>
    <span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@db</span>.<span class="ruby-identifier">has_key?</span> <span class="ruby-identifier">oid</span>.<span class="ruby-identifier">to_s</span>
      <span class="ruby-identifier">ret</span> = <span class="ruby-constant">Utility</span>.<span class="ruby-identifier">decode</span>(<span class="ruby-ivar">@db</span>[<span class="ruby-identifier">oid</span>.<span class="ruby-identifier">to_s</span>])
    <span class="ruby-keyword kw">else</span>
      <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:database_read_fails</span>)
      <span class="ruby-keyword kw">return</span> <span class="ruby-keyword kw">nil</span>
    <span class="ruby-keyword kw">end</span>
    <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:database_reads</span>)

    <span class="ruby-comment cmt"># get and remove the last entry off this list
</span>
    <span class="ruby-identifier">ch</span> = <span class="ruby-ivar">@cache</span>[<span class="ruby-identifier">hv</span>].<span class="ruby-identifier">pop</span>
    <span class="ruby-comment cmt"># if its dirty we write it to the database
</span>
    <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">ch</span>.<span class="ruby-identifier">dirty?</span> <span class="ruby-operator">&amp;&amp;</span> <span class="ruby-operator">!</span><span class="ruby-identifier">ch</span>.<span class="ruby-identifier">dead?</span>
      <span class="ruby-ivar">@db</span>[<span class="ruby-identifier">ch</span>.<span class="ruby-identifier">oid</span>.<span class="ruby-identifier">to_s</span>] = <span class="ruby-constant">Utility</span>.<span class="ruby-identifier">encode</span>(<span class="ruby-identifier">ch</span>.<span class="ruby-identifier">obj</span>)
      <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:database_writes</span>)
      <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">ch</span>.<span class="ruby-identifier">noswap?</span>  <span class="ruby-comment cmt"># here we have a problem we can't use this
</span>
        <span class="ruby-comment cmt"># first push it back onto the list
</span>
        <span class="ruby-ivar">@cache</span>[<span class="ruby-identifier">hv</span>].<span class="ruby-identifier">unshift</span> <span class="ruby-identifier">ch</span>
        <span class="ruby-comment cmt"># get ourselves a brand new
</span>
        <span class="ruby-identifier">ch</span> = <span class="ruby-constant">CacheEntry</span>.<span class="ruby-identifier">new</span>
        <span class="ruby-comment cmt"># problem solved
</span>
        <span class="ruby-comment cmt"># the depth of any list chains will be cache_depth + # noswap entries
</span>
      <span class="ruby-keyword kw">end</span>
    <span class="ruby-keyword kw">end</span>

    <span class="ruby-comment cmt"># assign our new object to the cache entry
</span>
    <span class="ruby-identifier">ch</span>.<span class="ruby-identifier">obj</span> = <span class="ruby-identifier">ret</span>
    <span class="ruby-identifier">ch</span>.<span class="ruby-identifier">oid</span> = <span class="ruby-identifier">oid</span>
    <span class="ruby-identifier">ch</span>.<span class="ruby-identifier">clean!</span>
    <span class="ruby-comment cmt"># push it to the head of the list
</span>
    <span class="ruby-ivar">@cache</span>[<span class="ruby-identifier">hv</span>].<span class="ruby-identifier">unshift</span> <span class="ruby-identifier">ch</span>

    <span class="ruby-identifier">ret</span>
  <span class="ruby-keyword kw">end</span>
</pre>
          </div>
        </div>
      </div>

      <div id="method-M000128" class="method-detail">
        <a name="M000128"></a>

        <div class="method-heading">
          <a href="#M000128" class="method-signature">
          <span class="method-name">hash</span><span class="method-args">(oid)</span>
          </a>
        </div>
      
        <div class="method-description">
          <p>
Our simple <a href="CacheManager.html#M000128">hash</a> algoritm. Our
database <a href="CacheManager.html#M000137">keys</a> are sequentially
assigned integers, so&#8230; I don&#8216;t know what would be better.
</p>
          <p><a class="source-toggle" href="#"
            onclick="toggleCode('M000128-source');return false;">[Source]</a></p>
          <div class="method-source-code" id="M000128-source">
<pre>
<span class="ruby-comment cmt"># File lib/storage/cache.rb, line 144</span>
  <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">hash</span>(<span class="ruby-identifier">oid</span>)
    <span class="ruby-identifier">oid</span> <span class="ruby-operator">%</span> <span class="ruby-ivar">@cwidth</span>
  <span class="ruby-keyword kw">end</span>
</pre>
          </div>
        </div>
      </div>

      <div id="method-M000127" class="method-detail">
        <a name="M000127"></a>

        <div class="method-heading">
          <a href="#M000127" class="method-signature">
          <span class="method-name">inspect</span><span class="method-args">()</span>
          </a>
        </div>
      
        <div class="method-description">
          <p>
report on the cache map see cmd_dumpcache
</p>
          <p><a class="source-toggle" href="#"
            onclick="toggleCode('M000127-source');return false;">[Source]</a></p>
          <div class="method-source-code" id="M000127-source">
<pre>
<span class="ruby-comment cmt"># File lib/storage/cache.rb, line 130</span>
  <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">inspect</span>
    <span class="ruby-identifier">str</span> = <span class="ruby-node">&quot;cache width:#{@cwidth} cache depth:#{@cdepth}\n&quot;</span>
    <span class="ruby-ivar">@cwidth</span>.<span class="ruby-identifier">times</span> <span class="ruby-keyword kw">do</span> <span class="ruby-operator">|</span><span class="ruby-identifier">i</span><span class="ruby-operator">|</span>
      <span class="ruby-ivar">@cache</span>[<span class="ruby-identifier">i</span>].<span class="ruby-identifier">each_with_index</span> <span class="ruby-keyword kw">do</span> <span class="ruby-operator">|</span><span class="ruby-identifier">ce</span>,<span class="ruby-identifier">j</span><span class="ruby-operator">|</span>
        <span class="ruby-keyword kw">next</span> <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">dead?</span>
        <span class="ruby-identifier">str</span> <span class="ruby-operator">&lt;&lt;</span> <span class="ruby-node">&quot;cache map [#{i}][#{j}] =&gt; &quot;</span>
        <span class="ruby-identifier">str</span> <span class="ruby-operator">&lt;&lt;</span> <span class="ruby-node">&quot;oid #{ce.oid} object_id #{ce.obj.object_id} dirty? #{ce.dirty?}  noswap? #{ce.noswap?}\n&quot;</span>
      <span class="ruby-keyword kw">end</span>
    <span class="ruby-keyword kw">end</span>
    <span class="ruby-identifier">str</span>
  <span class="ruby-keyword kw">end</span>
</pre>
          </div>
        </div>
      </div>

      <div id="method-M000137" class="method-detail">
        <a name="M000137"></a>

        <div class="method-heading">
          <a href="#M000137" class="method-signature">
          <span class="method-name">keys</span><span class="method-args">()</span>
          </a>
        </div>
      
        <div class="method-description">
          <p>
This is provided to traverse the entire object chain. This thrashes the
cache violently. See <a href="Store.html#M000084">Store#each</a>. One needs
to question the design of routines that use <a
href="Store.html#M000084">Store#each</a> above.
</p>
          <p><a class="source-toggle" href="#"
            onclick="toggleCode('M000137-source');return false;">[Source]</a></p>
          <div class="method-source-code" id="M000137-source">
<pre>
<span class="ruby-comment cmt"># File lib/storage/cache.rb, line 359</span>
  <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">keys</span>
    <span class="ruby-identifier">kys</span> = []
    <span class="ruby-ivar">@cwidth</span>.<span class="ruby-identifier">times</span> <span class="ruby-keyword kw">do</span> <span class="ruby-operator">|</span><span class="ruby-identifier">i</span><span class="ruby-operator">|</span>
      <span class="ruby-ivar">@cache</span>[<span class="ruby-identifier">i</span>].<span class="ruby-identifier">each</span> {<span class="ruby-operator">|</span><span class="ruby-identifier">ce</span><span class="ruby-operator">|</span> <span class="ruby-identifier">kys</span> <span class="ruby-operator">&lt;&lt;</span> <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">oid</span> <span class="ruby-keyword kw">if</span> <span class="ruby-operator">!</span><span class="ruby-identifier">ce</span>.<span class="ruby-identifier">oid</span>.<span class="ruby-identifier">nil?</span> }
    <span class="ruby-keyword kw">end</span>
    <span class="ruby-identifier">kys</span>
  <span class="ruby-keyword kw">end</span>
</pre>
          </div>
        </div>
      </div>

      <div id="method-M000135" class="method-detail">
        <a name="M000135"></a>

        <div class="method-heading">
          <a href="#M000135" class="method-signature">
          <span class="method-name">makenoswap</span><span class="method-args">(oid)</span>
          </a>
        </div>
      
        <div class="method-description">
          <p>
Mark an object in the cache as nonswappable
</p>
<dl>
<dt><tt>oid</tt></dt><dd>is the object id

</dd>
<dt><tt>return</tt></dt><dd>undefined

</dd>
</dl>
          <p><a class="source-toggle" href="#"
            onclick="toggleCode('M000135-source');return false;">[Source]</a></p>
          <div class="method-source-code" id="M000135-source">
<pre>
<span class="ruby-comment cmt"># File lib/storage/cache.rb, line 319</span>
  <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">makenoswap</span>(<span class="ruby-identifier">oid</span>)
    <span class="ruby-keyword kw">return</span> <span class="ruby-keyword kw">nil</span> <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">oid</span>.<span class="ruby-identifier">nil?</span>
    <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:cache_noswap</span>)
    <span class="ruby-identifier">hv</span> = <span class="ruby-identifier">hash</span>(<span class="ruby-identifier">oid</span>)

    <span class="ruby-ivar">@cache</span>[<span class="ruby-identifier">hv</span>].<span class="ruby-identifier">each</span> <span class="ruby-keyword kw">do</span> <span class="ruby-operator">|</span><span class="ruby-identifier">ce</span><span class="ruby-operator">|</span>
      <span class="ruby-keyword kw">next</span> <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">oid</span> <span class="ruby-operator">!=</span> <span class="ruby-identifier">oid</span>
      <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">noswap!</span>
      <span class="ruby-keyword kw">return</span>
    <span class="ruby-keyword kw">end</span>

    <span class="ruby-comment cmt"># This would indicate we've tried marking it noswap before we did a put.
</span>
    <span class="ruby-comment cmt"># A logic error
</span>
    <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:cache_noswap_misses</span>)
    <span class="ruby-identifier">log</span>.<span class="ruby-identifier">debug</span> <span class="ruby-node">&quot;Marking object nonswappable before put - #{oid}&quot;</span>
  <span class="ruby-keyword kw">end</span>
</pre>
          </div>
        </div>
      </div>

      <div id="method-M000136" class="method-detail">
        <a name="M000136"></a>

        <div class="method-heading">
          <a href="#M000136" class="method-signature">
          <span class="method-name">makeswap</span><span class="method-args">(oid)</span>
          </a>
        </div>
      
        <div class="method-description">
          <p>
Mark an object in the cache as swappable
</p>
<dl>
<dt><tt>oid</tt></dt><dd>is the object id

</dd>
<dt><tt>return</tt></dt><dd>undefined

</dd>
</dl>
          <p><a class="source-toggle" href="#"
            onclick="toggleCode('M000136-source');return false;">[Source]</a></p>
          <div class="method-source-code" id="M000136-source">
<pre>
<span class="ruby-comment cmt"># File lib/storage/cache.rb, line 339</span>
  <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">makeswap</span>(<span class="ruby-identifier">oid</span>)
    <span class="ruby-keyword kw">return</span> <span class="ruby-keyword kw">nil</span> <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">oid</span>.<span class="ruby-identifier">nil?</span>
    <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:cache_swap</span>)
    <span class="ruby-identifier">hv</span> = <span class="ruby-identifier">hash</span>(<span class="ruby-identifier">oid</span>)

    <span class="ruby-ivar">@cache</span>[<span class="ruby-identifier">hv</span>].<span class="ruby-identifier">each</span> <span class="ruby-keyword kw">do</span> <span class="ruby-operator">|</span><span class="ruby-identifier">ce</span><span class="ruby-operator">|</span>
      <span class="ruby-keyword kw">next</span> <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">oid</span> <span class="ruby-operator">!=</span> <span class="ruby-identifier">oid</span>
      <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">swap!</span>
      <span class="ruby-keyword kw">return</span>
    <span class="ruby-keyword kw">end</span>

    <span class="ruby-comment cmt"># This would indicate we've tried marking it swap before we did a put.
</span>
    <span class="ruby-comment cmt"># A logic error
</span>
    <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:cache_swap_misses</span>)
    <span class="ruby-identifier">log</span>.<span class="ruby-identifier">debug</span> <span class="ruby-node">&quot;Marking object swappable before put - #{oid}&quot;</span>
  <span class="ruby-keyword kw">end</span>
</pre>
          </div>
        </div>
      </div>

      <div id="method-M000132" class="method-detail">
        <a name="M000132"></a>

        <div class="method-heading">
          <a href="#M000132" class="method-signature">
          <span class="method-name">mark</span><span class="method-args">(oid)</span>
          </a>
        </div>
      
        <div class="method-description">
          <p>
deliberately <a href="CacheManager.html#M000132">mark</a> an object in the
cache as dirty see properties.
</p>
          <p><a class="source-toggle" href="#"
            onclick="toggleCode('M000132-source');return false;">[Source]</a></p>
          <div class="method-source-code" id="M000132-source">
<pre>
<span class="ruby-comment cmt"># File lib/storage/cache.rb, line 271</span>
  <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">mark</span>(<span class="ruby-identifier">oid</span>)
    <span class="ruby-keyword kw">return</span> <span class="ruby-keyword kw">nil</span> <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">oid</span>.<span class="ruby-identifier">nil?</span>
    <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:cache_marks</span>)
    <span class="ruby-identifier">hv</span> = <span class="ruby-identifier">hash</span>(<span class="ruby-identifier">oid</span>)

    <span class="ruby-ivar">@cache</span>[<span class="ruby-identifier">hv</span>].<span class="ruby-identifier">each</span> <span class="ruby-keyword kw">do</span> <span class="ruby-operator">|</span><span class="ruby-identifier">ce</span><span class="ruby-operator">|</span>
      <span class="ruby-keyword kw">next</span> <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">oid</span> <span class="ruby-operator">!=</span> <span class="ruby-identifier">oid</span>
      <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">dirty!</span>
      <span class="ruby-keyword kw">return</span>
    <span class="ruby-keyword kw">end</span>

    <span class="ruby-comment cmt"># this would indicate we've tried marking it dirty before we did a put.
</span>
    <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:cache_mark_misses</span>)
    <span class="ruby-identifier">log</span>.<span class="ruby-identifier">debug</span> <span class="ruby-node">&quot;Marking object dirty before put - #{oid}&quot;</span>
  <span class="ruby-keyword kw">end</span>
</pre>
          </div>
        </div>
      </div>

      <div id="method-M000130" class="method-detail">
        <a name="M000130"></a>

        <div class="method-heading">
          <a href="#M000130" class="method-signature">
          <span class="method-name">put</span><span class="method-args">(obj)</span>
          </a>
        </div>
      
        <div class="method-description">
          <p>
puts an object
</p>
<dl>
<dt><tt>obj</tt></dt><dd>- The integer object id to retrieve

</dd>
<dt><tt>return</tt></dt><dd>- undefined

</dd>
</dl>
          <p><a class="source-toggle" href="#"
            onclick="toggleCode('M000130-source');return false;">[Source]</a></p>
          <div class="method-source-code" id="M000130-source">
<pre>
<span class="ruby-comment cmt"># File lib/storage/cache.rb, line 203</span>
  <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">put</span>(<span class="ruby-identifier">obj</span>)
    <span class="ruby-keyword kw">return</span> <span class="ruby-keyword kw">nil</span> <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">obj</span>.<span class="ruby-identifier">nil?</span>
    <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:writes</span>)
    <span class="ruby-identifier">hv</span> = <span class="ruby-identifier">hash</span>(<span class="ruby-identifier">obj</span>.<span class="ruby-identifier">id</span>)

    <span class="ruby-comment cmt"># search the cache
</span>
    <span class="ruby-ivar">@cache</span>[<span class="ruby-identifier">hv</span>].<span class="ruby-identifier">each</span> <span class="ruby-keyword kw">do</span> <span class="ruby-operator">|</span><span class="ruby-identifier">ce</span><span class="ruby-operator">|</span>
      <span class="ruby-keyword kw">next</span> <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">oid</span> <span class="ruby-operator">!=</span> <span class="ruby-identifier">obj</span>.<span class="ruby-identifier">id</span>
      <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:cache_write_hits</span>) <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">dirty?</span>
      <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">obj</span>.<span class="ruby-identifier">object_id</span> <span class="ruby-operator">!=</span> <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">obj</span>.<span class="ruby-identifier">object_id</span>  <span class="ruby-comment cmt"># be safe
</span>
        <span class="ruby-comment cmt"># Be extra careful here.  It's possible we could have two objects
</span>
        <span class="ruby-comment cmt"># with the same object id but with different Ruby object_ids.
</span>
        <span class="ruby-comment cmt"># Most likely this is a bug, but we should handle it here..
</span>
        <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">obj</span> = <span class="ruby-identifier">obj</span>
        <span class="ruby-identifier">log</span>.<span class="ruby-identifier">warn</span> <span class="ruby-value str">&quot;Duplicate object id's in cache!&quot;</span>
        <span class="ruby-identifier">log</span>.<span class="ruby-identifier">warn</span> <span class="ruby-node">&quot;insert - #{obj.inspect}&quot;</span>
        <span class="ruby-identifier">log</span>.<span class="ruby-identifier">warn</span> <span class="ruby-node">&quot;cache - #{obj.inspect}&quot;</span>
      <span class="ruby-keyword kw">end</span>
      <span class="ruby-comment cmt"># need to try putting hot hit to the head of the list?
</span>
      <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">dirty!</span>
      <span class="ruby-keyword kw">return</span>
    <span class="ruby-keyword kw">end</span>

    <span class="ruby-comment cmt"># get and remove the last entry off this list
</span>
    <span class="ruby-identifier">ch</span> = <span class="ruby-ivar">@cache</span>[<span class="ruby-identifier">hv</span>].<span class="ruby-identifier">pop</span>
    <span class="ruby-comment cmt"># if its dirty we write it to the database
</span>
    <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">ch</span>.<span class="ruby-identifier">dirty?</span> <span class="ruby-operator">&amp;&amp;</span> <span class="ruby-operator">!</span><span class="ruby-identifier">ch</span>.<span class="ruby-identifier">dead?</span>
      <span class="ruby-comment cmt"># errors possible - check in store module
</span>
      <span class="ruby-ivar">@db</span>[<span class="ruby-identifier">ch</span>.<span class="ruby-identifier">oid</span>.<span class="ruby-identifier">to_s</span>] = <span class="ruby-constant">Utility</span>.<span class="ruby-identifier">encode</span>(<span class="ruby-identifier">ch</span>.<span class="ruby-identifier">obj</span>)
      <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:database_writes</span>)
      <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">ch</span>.<span class="ruby-identifier">noswap?</span>  <span class="ruby-comment cmt"># here we have a problem we can't use this
</span>
        <span class="ruby-comment cmt"># first push it back onto the list
</span>
        <span class="ruby-ivar">@cache</span>[<span class="ruby-identifier">hv</span>].<span class="ruby-identifier">unshift</span> <span class="ruby-identifier">ch</span>
        <span class="ruby-comment cmt"># get ourselves a brand new
</span>
        <span class="ruby-identifier">ch</span> = <span class="ruby-constant">CacheEntry</span>.<span class="ruby-identifier">new</span>
        <span class="ruby-comment cmt"># problem solved
</span>
        <span class="ruby-comment cmt"># the depth of any list chains will be cache_depth + # noswap entries
</span>
      <span class="ruby-keyword kw">end</span>
    <span class="ruby-keyword kw">end</span>

    <span class="ruby-comment cmt"># assign our new object to the cache entry
</span>
    <span class="ruby-identifier">ch</span>.<span class="ruby-identifier">obj</span> = <span class="ruby-identifier">obj</span>
    <span class="ruby-identifier">ch</span>.<span class="ruby-identifier">oid</span> = <span class="ruby-identifier">obj</span>.<span class="ruby-identifier">id</span>
    <span class="ruby-identifier">ch</span>.<span class="ruby-identifier">dirty!</span>
    <span class="ruby-comment cmt"># push it to the head of the list
</span>
    <span class="ruby-ivar">@cache</span>[<span class="ruby-identifier">hv</span>].<span class="ruby-identifier">unshift</span> <span class="ruby-identifier">ch</span>

    <span class="ruby-keyword kw">return</span>
  <span class="ruby-keyword kw">end</span>
</pre>
          </div>
        </div>
      </div>

      <div id="method-M000138" class="method-detail">
        <a name="M000138"></a>

        <div class="method-heading">
          <a href="#M000138" class="method-signature">
          <span class="method-name">stats</span><span class="method-args">()</span>
          </a>
        </div>
      
        <div class="method-description">
          <p>
produce a report - see cmd_stats
</p>
          <p><a class="source-toggle" href="#"
            onclick="toggleCode('M000138-source');return false;">[Source]</a></p>
          <div class="method-source-code" id="M000138-source">
<pre>
<span class="ruby-comment cmt"># File lib/storage/cache.rb, line 368</span>
  <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">stats</span>
    <span class="ruby-identifier">str</span> =  <span class="ruby-value str">&quot;----------* Cache Statistics *----------\n&quot;</span>
    <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">each</span> <span class="ruby-keyword kw">do</span> <span class="ruby-operator">|</span><span class="ruby-identifier">k</span>,<span class="ruby-identifier">v</span><span class="ruby-operator">|</span>
      <span class="ruby-identifier">str</span> <span class="ruby-operator">&lt;&lt;</span> <span class="ruby-identifier">sprintf</span>(<span class="ruby-value str">&quot;%25-25s : %d\n&quot;</span>,<span class="ruby-identifier">k</span>.<span class="ruby-identifier">to_s</span>.<span class="ruby-identifier">gsub</span>(<span class="ruby-regexp re">/_/</span>,<span class="ruby-value str">' '</span>),<span class="ruby-identifier">v</span>)
    <span class="ruby-keyword kw">end</span>
    <span class="ruby-identifier">str</span> <span class="ruby-operator">&lt;&lt;</span> <span class="ruby-value str">&quot;----------*                  *----------\n&quot;</span>
  <span class="ruby-keyword kw">end</span>
</pre>
          </div>
        </div>
      </div>

      <div id="method-M000133" class="method-detail">
        <a name="M000133"></a>

        <div class="method-heading">
          <a href="#M000133" class="method-signature">
          <span class="method-name">sync</span><span class="method-args">()</span>
          </a>
        </div>
      
        <div class="method-description">
          <p>
syncronize the entire cache with the database called by save.
</p>
          <p><a class="source-toggle" href="#"
            onclick="toggleCode('M000133-source');return false;">[Source]</a></p>
          <div class="method-source-code" id="M000133-source">
<pre>
<span class="ruby-comment cmt"># File lib/storage/cache.rb, line 289</span>
  <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">sync</span>
    <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:cache_syncs</span>)
    <span class="ruby-comment cmt"># search the list chains for dirty objects and write them out.
</span>
    <span class="ruby-ivar">@cwidth</span>.<span class="ruby-identifier">times</span> <span class="ruby-keyword kw">do</span> <span class="ruby-operator">|</span><span class="ruby-identifier">i</span><span class="ruby-operator">|</span>
      <span class="ruby-ivar">@cache</span>[<span class="ruby-identifier">i</span>].<span class="ruby-identifier">each</span> <span class="ruby-keyword kw">do</span> <span class="ruby-operator">|</span><span class="ruby-identifier">ce</span><span class="ruby-operator">|</span>
        <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">dirty?</span>
          <span class="ruby-ivar">@db</span>[<span class="ruby-identifier">ce</span>.<span class="ruby-identifier">oid</span>.<span class="ruby-identifier">to_s</span>] = <span class="ruby-constant">Utility</span>.<span class="ruby-identifier">encode</span>(<span class="ruby-identifier">ce</span>.<span class="ruby-identifier">obj</span>)
          <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:database_writes</span>)
          <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">clean!</span>
        <span class="ruby-keyword kw">end</span>
      <span class="ruby-keyword kw">end</span>
    <span class="ruby-keyword kw">end</span>
  <span class="ruby-keyword kw">end</span>
</pre>
          </div>
        </div>
      </div>

      <div id="method-M000134" class="method-detail">
        <a name="M000134"></a>

        <div class="method-heading">
          <a href="#M000134" class="method-signature">
          <span class="method-name">sync_chain</span><span class="method-args">(i)</span>
          </a>
        </div>
      
        <div class="method-description">
          <p>
syncronize a specific list chain not yet called but included for possible
performance enhancement
</p>
          <p><a class="source-toggle" href="#"
            onclick="toggleCode('M000134-source');return false;">[Source]</a></p>
          <div class="method-source-code" id="M000134-source">
<pre>
<span class="ruby-comment cmt"># File lib/storage/cache.rb, line 305</span>
  <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">sync_chain</span>(<span class="ruby-identifier">i</span>)
    <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:chain_syncs</span>)
    <span class="ruby-ivar">@cache</span>[<span class="ruby-identifier">i</span>].<span class="ruby-identifier">each</span> <span class="ruby-keyword kw">do</span> <span class="ruby-operator">|</span><span class="ruby-identifier">ce</span><span class="ruby-operator">|</span>
      <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">dirty?</span>
        <span class="ruby-ivar">@db</span>[<span class="ruby-identifier">ce</span>.<span class="ruby-identifier">oid</span>.<span class="ruby-identifier">to_s</span>] = <span class="ruby-constant">Utility</span>.<span class="ruby-identifier">encode</span>(<span class="ruby-identifier">ce</span>.<span class="ruby-identifier">obj</span>)
        <span class="ruby-ivar">@st</span>.<span class="ruby-identifier">inc</span>(<span class="ruby-identifier">:database_writes</span>)
        <span class="ruby-identifier">ce</span>.<span class="ruby-identifier">clean!</span>
      <span class="ruby-keyword kw">end</span>
    <span class="ruby-keyword kw">end</span>
  <span class="ruby-keyword kw">end</span>
</pre>
          </div>
        </div>
      </div>


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