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https://issues.apache.org/jira/browse/HDFS-10740?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15414326#comment-15414326
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James Clampffer commented on HDFS-10740:
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Cool stuff, relatively minor comments. A little more picky than usual since
this is an API usage example.
You might want to rename the "width" argument in the usage message to something
like "fanout". To me width could mean number of directories in each subdir or
number of all leaf nodes at the top of the tree. This is just my preference,
I'm fine with the current comment.
Comment no longer applicable, could you please replace this with "man" style
instructions on usage and any optional flags? At some point we need to start
commenting in the same markup as the rest of the HDFS native code as well.
{code}
/*
A a stripped down version of unix's "cat".
Doesn't deal with any flags for now, will just attempt to read the whole file.
*/
{code}
Since this is at least partly intended to be in example about how to take
advantage of the async operations some more comments would go a long way. Just
basic things about how the recursion doesn't block and how everything waits on
the promises later on.
Bringing the whole namespaces into scope can lead to weirdness. You could also
just add the definitions you want "using std::string" etc. Not a blocker since
nothing it's a standalone util but lets try to avoid this outside of the
examples and test directories.
{code}
using namespace std;
using namespace hdfs;
{code}
Generally taking references to any kind of smart_ptr as arguments is a bad
idea. Taking references to unique_ptr is a really bad idea because it's
sidestepping the contract that it's supposed to be unique and will lead to
confusion. Taking a raw pointer using .get() and passing it around is slightly
better because the loss of uniqueness is explicit.
{code}
unique_ptr<FileSystem> & fs
{code}
get_port will return an optional, if that hasn't been set it's undefined
behavior to use the deference operator or otherwise retrieve the value. That
might end up making the error message useless depending on what libstdc++ feels
like doing.
{code}
cerr << "Could not connect to " << uri->get_host() << ":" << *(uri->get_port())
<< endl;
{code}
> libhdfs++: Implement recursive directory generator
> --------------------------------------------------
>
> Key: HDFS-10740
> URL: https://issues.apache.org/jira/browse/HDFS-10740
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: hdfs-client
> Reporter: Anatoli Shein
> Assignee: Anatoli Shein
> Attachments: HDFS-10740.HDFS-8707.000.patch
>
>
> This tool will allow us do benchmarking/testing our find functionality, and
> will be a good example showing how to call a large number or namenode
> operations reqursively.
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