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APR::Brigade - Perl API for manipulating APR Bucket Brigades






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Table of Contents

Synopsis

  use APR::Brigade ();
  
  $bb = APR::Brigade->new($r->pool, $c->bucket_alloc);
  $ba = $bb->bucket_alloc();
  $pool = $bb->pool;
  
  $bb->insert_head($b);
  $bb->insert_tail($b);
  
  $b_first = $bb->first;
  $b_last  = $bb->last;
  
  $b_prev = $bb->prev($b_last);
  $b_next = $bb->next($b);
  
  $bb2 = APR::Brigade->new($r->pool, $c->bucket_alloc);
  $bb1->concat($bb2);
  
  $len = $bb->flatten($data);
  $len = $bb2->flatten($data, $wanted);
  
  $len = $bb->length;
  $bb3 = $bb->split($b_last);
  
  last if $bb->is_empty();
  $bb->cleanup();
  $bb->destroy();


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Description

APR::Brigade allows you to create, manipulate and delete APR bucket brigades.



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API

APR::Brigade provides the following functions and/or methods:



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cleanup

Empty out an entire bucket brigade:

  $bb->cleanup;

This method destroys all of the buckets within the bucket brigade's bucket list. This is similar to destroy(), except that it does not deregister the brigade's pool() cleanup function.

Generally, you should use destroy(). This function can be useful in situations where you have a single brigade that you wish to reuse many times by destroying all of the buckets in the brigade and putting new buckets into it later.



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concat

Concatenate brigade $bb2 onto the end of brigade $bb1, leaving brigade $bb2 empty:

  $bb1->concat($bb2);


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destroy

destroy an entire bucket brigade, includes all of the buckets within the bucket brigade's bucket list.

  $bb->destroy();


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is_empty

Test whether the bucket brigade is empty

  $ret = $bb->is_empty();


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first

Return the first bucket in a brigade

  $b_first = $bb->first;


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flatten

Get the data from buckets in the bucket brigade as one string

  $len = $bb->flatten($buffer);
  $len = $bb->flatten($buffer, $wanted);


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insert_head

Insert a list of buckets at the front of a brigade

  $bb->insert_head($b);


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insert_tail

Insert a list of buckets at the end of a brigade

  $bb->insert_tail($b);


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last

Return the last bucket in the brigade

  $b_last = $bb->last;


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length

Return the total length of the data in the brigade (not the number of buckets)

  $len = $bb->length;


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new

  my $nbb = APR::Brigade->new($p, $bucket_alloc);
  my $nbb =          $bb->new($p, $bucket_alloc);

Example:

Create a new bucket brigade, using the request object's pool:

  use Apache2::Connection ();
  use Apache2::RequestRec ();
  use APR::Brigade ();
  my $bb = APR::Brigade->new($r->pool, $r->connection->bucket_alloc);


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bucket_alloc

Get the bucket allocator associated with this brigade.

  my $ba = $bb->bucket_alloc();


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next

Return the next bucket in a brigade

  $b_next = $bb->next($b);


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pool

The pool the brigade is associated with.

  $pool = $bb->pool;

The data is not allocated out of the pool, but a cleanup is registered with this pool. If the brigade is destroyed by some mechanism other than pool destruction, the destroying function is responsible for killing the registered cleanup.



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prev

Return the previous bucket in the brigade

  $b_prev = $bb->prev($b);


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split

Split a bucket brigade into two, such that the given bucket is the first in the new bucket brigade.

  $bb2 = $bb->split($b);

This function is useful when a filter wants to pass only the initial part of a brigade to the next filter.

Example:

Create a bucket brigade with three buckets, and split it into two brigade such that the second brigade will have the last two buckets.

  my $bb1 = APR::Brigade->new($r->pool, $c->bucket_alloc);
  my $ba  = $c->bucket_alloc();
  $bb1->insert_tail(APR::Bucket->new($ba, "1"));
  $bb1->insert_tail(APR::Bucket->new($ba, "2"));
  $bb1->insert_tail(APR::Bucket->new($ba, "3"));

$bb1 now contains buckets "1", "2", "3". Now do the split at the second bucket:

  my $b = $bb1->first; # 1
  $b = $bb1->next($b); # 2
  my $bb2 = $bb1->split($b);

Now $bb1 contains bucket "1". $bb2 contains buckets: "2", "3"



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See Also

mod_perl 2.0 documentation.



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Copyright

mod_perl 2.0 and its core modules are copyrighted under The Apache Software License, Version 2.0.



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Authors

The mod_perl development team and numerous contributors.






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