APR::Brigade(3) Perl API for manipulating APR Bucket Brigades

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();

Description

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

API

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

cleanup

Empty out an entire bucket brigade: 

  $bb->cleanup;
obj: $bb ( "APR::Brigade object" )
The brigade to cleanup
ret: no return value
since: 2.0.00

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.

concat

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

  $bb1->concat($bb2);
obj: $bb1 ( "APR::Brigade object" )
The brigade to concatenate to.
arg1: $bb2 ( "APR::Brigade object" )
The brigade to concatenate and empty afterwards.
ret: no return value
since: 2.0.00

destroy

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

  $bb->destroy();
obj: $bb ( "APR::Brigade object" )
The bucket brigade to destroy.
ret: no return value
excpt: "APR::Error"
since: 2.0.00

is_empty

Test whether the bucket brigade is empty 

  $ret = $bb->is_empty();
obj: $bb ( "APR::Brigade object" )
ret: $ret ( boolean )
since: 2.0.00

first

Return the first bucket in a brigade 

  $b_first = $bb->first;
obj: $bb ( "APR::Brigade object" )
ret: $b_first ( "APR::Bucket object" )
The first bucket in the bucket brigade $bb.

"undef" is returned if there are no buckets in $bb.

since: 2.0.00

flatten

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

  $len = $bb->flatten($buffer);
  $len = $bb->flatten($buffer, $wanted);
obj: $bb ( "APR::Brigade object" )
arg1: $buffer ( SCALAR )
The buffer to fill. All previous data will be lost.
opt arg2: $wanted ( number )
If no argument is passed then all data will be returned. If $wanted is specified --- that number or less bytes will be returned.
ret: $len ( number )
How many bytes were actually read.

$buffer gets populated with the string that is read. It will contain an empty string if there was nothing to read.

since: 2.0.00
excpt: "APR::Error"

insert_head

Insert a list of buckets at the front of a brigade 

  $bb->insert_head($b);
obj: $bb ( "APR::Brigade object" )
Brigade to insert into
arg1: $b ( "APR::Bucket object" )
the bucket to insert. More buckets could be attached to that bucket.
ret: no return value
since: 2.0.00

insert_tail

Insert a list of buckets at the end of a brigade 

  $bb->insert_tail($b);
obj: $bb ( "APR::Brigade object" )
Brigade to insert into
arg1: $b ( "APR::Bucket object" )
the bucket to insert. More buckets could be attached to that bucket.
ret: no return value
since: 2.0.00

last

Return the last bucket in the brigade 

  $b_last = $bb->last;
obj: $bb ( "APR::Brigade object" )
ret: $b_last ( "APR::Bucket object" )
The last bucket in the bucket brigade $bb.

"undef" is returned if there are no buckets in $bb.

since: 2.0.00

length

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

  $len = $bb->length;
obj: $bb ( "APR::Brigade object" )
ret: $len ( number )
since: 2.0.00

new

  my $nbb = APR::Brigade->new($p, $bucket_alloc);
  my $nbb =          $bb->new($p, $bucket_alloc);
obj: $bb ( "APR::Brigade object or class" )
arg1: $p ( "APR::Pool object" )
arg2: $bucket_alloc ( "APR::BucketAlloc object" )
ret: $nbb ( "APR::Brigade object" )
a newly created bucket brigade object
since: 2.0.00

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);

bucket_alloc

Get the bucket allocator associated with this brigade. 

  my $ba = $bb->bucket_alloc();
obj: $bb ( "APR::Brigade object or class" )
ret: $ba ( "APR::BucketAlloc object" )
since: 2.0.00

next

Return the next bucket in a brigade 

  $b_next = $bb->next($b);
obj: $bb ( "APR::Brigade object" )
arg1: $b ( "APR::Bucket object" )
The bucket after which the next bucket $b_next is located
ret: $b_next ( "APR::Bucket object" )
The next bucket after bucket $b.

"undef" is returned if there is no next bucket (i.e. $b is the last bucket).

since: 2.0.00

pool

The pool the brigade is associated with. 

  $pool = $bb->pool;
obj: $bb ( "APR::Brigade object" )
ret: $pool ( "APR::Pool object" )
since: 2.0.00

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.

prev

Return the previous bucket in the brigade 

  $b_prev = $bb->prev($b);
obj: $bb ( "APR::Brigade object" )
arg1: $b ( "APR::Bucket object" )
The bucket located after bucket $b_prev
ret: $b_prev ( "APR::Bucket object" )
The bucket located before bucket $b.

"undef" is returned if there is no previous bucket (i.e. $b is the first bucket).

since: 2.0.00

split

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

  $bb2 = $bb->split($b);
obj: $bb ( "APR::Brigade object" )
The brigade to split
arg1: $b ( "APR::Bucket object" )
The first bucket of the new brigade
ret: $bb2 ( "APR::Brigade object" )
The new brigade.
since: 2.0.00

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''

See Also

mod_perl 2.0 documentation.

Copyright

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

Authors

The mod_perl development team and numerous contributors.

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