Merged revisions 222878 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.4

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  r222878 | russell | 2009-10-08 14:45:47 -0500 (Thu, 08 Oct 2009) | 44 lines
  
  Make filestream frame handling safer by isolating frames before returning them.
  
  This patch is related to a number of issues on the bug tracker that show
  crashes related to freeing frames that came from a filestream.  A number of
  fixes have been made over time while trying to figure out these problems, but
  there re still people seeing the crash.  (Note that some of these bug reports
  include information about other problems.  I am specifically addressing
  the filestream frame crash here.)
  
  I'm still not clear on what the exact problem is.  However, what is _very_
  clear is that we have seen quite a few problems over time related to unexpected
  behavior when we try to use embedded frames as an optimization.  In some cases,
  this optimization doesn't really provide much due to improvements made in other
  areas.
  
  In this case, the patch modifies filestream handling such that the embedded frame
  will not be returned.  ast_frisolate() is used to ensure that we end up with a
  completely mallocd frame.  In reality, though, we will not actually have to malloc
  every time.  For filestreams, the frame will almost always be allocated and freed
  in the same thread.  That means that the thread local frame cache will be used.
  So, going this route doesn't hurt.
  
  With this patch in place, some people have reported success in not seeing the
  crash anymore.
  
  (SWP-150)
  (AST-208)
  (ABE-1834)
  
  (issue #15609)
  Reported by: aragon
  Patches:
        filestream_frisolate-1.4.diff2.txt uploaded by russell (license 2)
  Tested by: aragon, russell
  
  (closes issue #15817)
  Reported by: zerohalo
  Tested by: zerohalo
  
  (closes issue #15845)
  Reported by: marhbere
  
  Review: https://reviewboard.asterisk.org/r/386/
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