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This is an automatically generated e-mail. To reply, visit:
<a href="https://reviewboard.asterisk.org/r/2596/">https://reviewboard.asterisk.org/r/2596/</a>
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<a href="https://reviewboard.asterisk.org/r/2596/diff/2/?file=39172#file39172line545" style="color: black; font-weight: bold; text-decoration: underline;">trunk/include/asterisk/stasis.h</a>
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(Diff revision 2)
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="cm"> * \return Message which, when sent to the \a topic, will clear the item from the cache.</span></pre></td>
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<pre style="margin-left: 2em; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">You should note that the data in the message it the current snapshot from the cache.</pre>
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<a href="https://reviewboard.asterisk.org/r/2596/diff/2/?file=39176#file39176line283" style="color: black; font-weight: bold; text-decoration: underline;">trunk/main/stasis_cache.c</a>
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<td colspan="4"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">struct ao2_container *stasis_cache_dump(struct stasis_caching_topic *caching_topic, struct stasis_message_type *type)</pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="cm">/* strcpy safe */</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="n">msg</span> <span class="o">=</span> <span class="n">stasis_message_create</span><span class="p">(</span><span class="n">stasis_cache_clear_type</span><span class="p">(),</span> <span class="n">cached_msg</span><span class="p">);</span></pre></td>
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<pre style="margin-left: 2em; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">There's a potential problem with pulling the snapshot from the cache instead of creating the snapshot fresh.
Since the cache updates happen asynchronously in the Stasis thread pool, this could be an old snapshot. Not a problem currently, but will be if someone tries to use that snapshot as the final state of the object.
What's more problematic is that for a very short lived object, it may attempt to create the cache_clear message before there's an entry in the cache. Then the clear creation will fail, and the cache will have a ZOMBIE SNAPSHOT THAT WILL NOT DIE.</pre>
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<a href="https://reviewboard.asterisk.org/r/2596/diff/2/?file=39176#file39176line368" style="color: black; font-weight: bold; text-decoration: underline;">trunk/main/stasis_cache.c</a>
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<td colspan="4"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">static void caching_topic_exec(void *data, struct stasis_subscription *sub, struct stasis_topic *topic, struct stasis_message *message)</pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="n">ast_assert</span><span class="p">(</span><span class="n">clear</span><span class="o">-></span><span class="n">type</span> <span class="o">!=</span> <span class="nb">NULL</span><span class="p">);</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="k">const</span> <span class="kt">char</span> <span class="o">*</span><span class="n">clear_id</span> <span class="o">=</span> <span class="n">caching_topic</span><span class="o">-></span><span class="n">id_fn</span><span class="p">(</span><span class="n">clear_msg</span><span class="p">);</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="n">ast_assert</span><span class="p">(</span><span class="n">clear</span><span class="o">-></span><span class="n">id</span> <span class="o">!=</span> <span class="nb">NULL</span><span class="p">);</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="k">struct</span> <span class="n">stasis_message_type</span> <span class="o">*</span><span class="n">clear_type</span> <span class="o">=</span> <span class="n">stasis_message_type</span><span class="p">(</span><span class="n">clear_msg</span><span class="p">);</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="n">old_snapshot</span> <span class="o">=</span> <span class="n">cache_put</span><span class="p">(</span><span class="n">caching_topic</span><span class="p">,</span> <span class="n">clear</span><span class="o">-></span><span class="n">type</span><span class="p">,</span> <span class="n">clear</span><span class="o">-></span><span class="n">id</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">);</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="n">ast_assert</span><span class="p">(</span><span class="n">clear_type</span> <span class="o">!=</span> <span class="nb">NULL</span><span class="p">);</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="n">ast_assert</span><span class="p">(</span><span class="n">clear_id</span> <span class="o">!=</span> <span class="nb">NULL</span><span class="p">);</span></pre></td>
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<pre style="margin-left: 2em; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">id_fn will return NULL if the message is of the wrong type. This will happen for the channel_snapshot clears that get forwarded to the endpoint cache.
If id_fn returns NULL, this should just forward the message and return.</pre>
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<a href="https://reviewboard.asterisk.org/r/2596/diff/2/?file=39176#file39176line379" style="color: black; font-weight: bold; text-decoration: underline;">trunk/main/stasis_cache.c</a>
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<td colspan="4"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">static void caching_topic_exec(void *data, struct stasis_subscription *sub, struct stasis_topic *topic, struct stasis_message *message)</pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="cm">/* While this could be a problem, it's very likely to</span></pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="cm">/* While this could be a problem, it's very likely to</span></pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="cm"><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span> * happen with message forwarding */</span></pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="cm"><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span> * happen with message forwarding */</span></pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="n">ast_debug</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span></pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="n">ast_debug</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span></pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="s">"Attempting to remove an item from the cache that isn't there: %s %s</span><span class="se">\n</span><span class="s">"</span><span class="p">,</span></pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="s">"Attempting to remove an item from the cache that isn't there: %s %s</span><span class="se">\n</span><span class="s">"</span><span class="p">,</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="n">stasis_message_type_name</span><span class="p">(</span><span class="n">clear</span><span class="o"><span class="hl">-></span></span><span class="n">type</span><span class="p">),</span> <span class="n">clear</span><span class="o"><span class="hl">-></span></span><span class="n">id</span><span class="p">);</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="n">stasis_message_type_name</span><span class="p">(</span><span class="n">clear<span class="hl">_</span>type</span><span class="p">),</span> <span class="n">clear<span class="hl">_</span>id</span><span class="p">);</span></pre></td>
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<pre style="margin-left: 2em; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">Once you handle id_fn returning NULL, this comment will be a lie. Remove the comment and change this to an ast_log(LOG_ERROR</pre>
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<p>- David</p>
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<p>On June 6th, 2013, 8:21 a.m. CDT, opticron wrote:</p>
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<div>Review request for Asterisk Developers and David Lee.</div>
<div>By opticron.</div>
<p style="color: grey;"><i>Updated June 6, 2013, 8:21 a.m.</i></p>
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<b style="color: #575012; font-size: 10pt;">Repository: </b>
Asterisk
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Description </h1>
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<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">This reworks the stasis cache clear mechanism such that an actual snapshot message is published inside of the cache clear message instead of the stasis_cache_clear structure (the ID and message type) which has been removed. This allows multiple caches to consume the same clear message and avoids the problems of needing to clear unknown secondary caches which may be keyed on different parts of the snapshot.
This also resolves an issue where a channel snapshot could be cleared from the channel snapshot cache multiple times if multiple threads called ast_hangup on the channel at the same time.
This also resolves an issue where an endpoint snapshot was published after it was cleared from the cache, thus repopulating it in the cache.</pre>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
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<li>trunk/include/asterisk/stasis.h <span style="color: grey">(390501)</span></li>
<li>trunk/main/bridging.c <span style="color: grey">(390501)</span></li>
<li>trunk/main/channel.c <span style="color: grey">(390501)</span></li>
<li>trunk/main/endpoints.c <span style="color: grey">(390501)</span></li>
<li>trunk/main/stasis_cache.c <span style="color: grey">(390501)</span></li>
<li>trunk/tests/test_stasis.c <span style="color: grey">(390501)</span></li>
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<p><a href="https://reviewboard.asterisk.org/r/2596/diff/" style="margin-left: 3em;">View Diff</a></p>
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