tree a8694cf8333a3fc498e397deae2d3c8fd8f8f9de
parent 4bc7827e5bc7e55996832dfbac251486c28b6d1a
author Roman Arutyunyan <arut@nginx.com> 1467464393 +0300
committer Roman Arutyunyan <arut@nginx.com> 1467464393 +0300

Sub filter: eliminate unnecessary buffering.

Previously, when a buffer was processed by the sub filter, its final bytes
could be buffered by the filter even if they don't match any pattern.
This happened because the Boyer-Moore algorithm, employed by the sub filter
since b9447fc457b4 (1.9.4), matches the last characters of patterns prior to
checking other characters.  If the last character is out of scope, initial
bytes of a potential match are buffered until the last character is available.

Now, after receiving a flush or recycled buffer, the filter performs
additional checks to reduce the number of buffered bytes.  The potential match
is checked against the initial parts of all patterns.  Non-matching bytes are
not buffered.  This improves processing of a chunked response from upstream
by sending the entire chunks without buffering unless a partial match is found
at the end of a chunk.