fix#123fix#154fix#265
This completely replaces the HTTP parser used to read and
parse incoming messages. The new version is faster than
the old one, and written in fewer lines. A summary of
changes:
* parse and async_parse renamed to read and async_read
* basic_parser is optimized for linear buffers,
use flat_streambuf for the best performance with these
functions:
- http::read
- http::read_some
- http::async_read
- http::async_read_some
* The overloads of read() and async_read() which take
just a header have been removed, since they would
throw away important parse metadata.
* The derived class callbacks for basic_parser have
been streamlined. All strings passed to callbacks
are presented in their entirety, instead of being
provided in pieces.
These changes allow use-cases that were previously
difficult or impossible, such as:
- Efficient relaying
- Late body type commitment
- Expect: 100-continue handling
fix#171
Several names and HTTP identifiers are renamed to be
more consistent, self-explanatory, and concise:
* "Fields" is a collection of HTTP header fields (rfc7230 section 3.2)
* "Header" is the Start Line plus Fields. Another way to look at it is,
the HTTP message minus the body.
* `basic_fields` replaces `basic_headers`
* `fields` replaces `headers`
* `Fields` replaces `Headers` in template parameter lists
* `header` replaces `message_headers`
* `header::fields` replaces `message_headers::fields`
The changes are cosmetic and do not affect run-time behavior.
