Rework and improve the decompress stream handler

The read buffer was changed into an iovec to avoid doing
too many binary concatenations and allocations.

Decompression happens transparently: when decoding gzip,
the content-encoding header is removed (we only decode
when "gzip" is the only encoding so nothing remains).

We always add a content_decoded key to the Req object.
This key contains a list of codings that were decoded,
in the reverse order in which they were. Currently it
can only be empty or contain <<"gzip">> but future
improvements or user handlers may see it contain more
values.

The option to disable decompression was renamed to
decompress_enabled and defaults to true.

It is no longer possible to enable/disable decompression
in the middle of reading the body: this ensures that the
data we pass forward is always valid.

Various smaller improvements were made to the code,
tests and manual pages.

1 files changed, 3 insertions, 3 deletions

diff --git a/doc/src/guide/streams.asciidoc b/doc/src/guide/streams.asciidoc
index b6e4d34..e8ddae0 100644
--- a/doc/src/guide/streams.asciidoc
+++ b/doc/src/guide/streams.asciidoc
@@ -66,9 +66,9 @@ enabled by default. It is a good example for writing your
 own handlers that will modify responses.
 
 link:man:cowboy_decompress_h(3)[cowboy_decompress_h] will
-automatically decompress requests when possible. It is not
-enabled by default. It is a good example for writing your
-own handlers that will modify requests.
+automatically decompress request bodies when possible.
+It is not enabled by default. It is a good example for
+writing your own handlers that will modify requests.
 
 link:man:cowboy_metrics_h(3)[cowboy_metrics_h] gathers
 metrics about a stream then passes them to a configurable