Beast.HTTP:

New classes are introduced to represent HTTP messages and their
associated bodies. The parser interface is reworked to use CRTP,
error codes, and trait checks.

New classes:

* basic_headers

  Models field/value pairs in a HTTP message.

* message

  Models a HTTP message, body behavior defined by template argument.
  Parsed message carries metadata generated during parsing.

* parser

  Produces parsed messages.

* empty_body, string_body, basic_streambuf_body

  Classes used to represent content bodies in various ways.

New functions:

* read, async_read, write, async_write

  Read and write HTTP messages on a socket.

New concepts:

* Body: Represents the HTTP Content-Body.
* Field: A HTTP header field.
* FieldSequence: A forward sequence of fields.
* Reader: Parses a Body from a stream of bytes.
* Writer: Serializes a Body to buffers.

basic_parser changes:

* add write methods which throw exceptions instead
* error_code passed via parameter instead of return value
* fold private member calls into existing callbacks
* basic_parser uses CRTP instead of virtual members
* add documentation on Derived requirements for CRTP

impl/http-parser changes:

* joyent renamed to nodejs to reflect upstream changes

examples/file_body.h

@@ -0,0 +1,94 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of Beast: https://github.com/vinniefalco/Beast
+    Copyright 2013, Vinnie Falco <vinnie.falco@gmail.com>
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#ifndef BEAST_EXAMPLE_FILE_BODY_H_INCLUDED
+#define BEAST_EXAMPLE_FILE_BODY_H_INCLUDED
+
+#include <beast/http/message.h>
+#include <beast/http/resume_context.h>
+#include <boost/asio/buffer.hpp>
+#include <boost/filesystem.hpp>
+#include <cstdio>
+#include <cstdint>
+
+namespace beast {
+namespace http {
+
+struct file_body
+{
+    using value_type = std::string;
+
+    class writer
+    {
+        std::size_t size_;
+        std::size_t offset_ = 0;
+        std::string const& path_;
+        FILE* file_ = nullptr;
+        char buf_[4096];
+        std::size_t buf_len_;
+
+    public:
+        static bool constexpr is_single_pass = false;
+
+        template<bool isRequest, class Headers>
+        writer(message<isRequest, file_body, Headers> const& m) noexcept
+            : path_(m.body)
+        {
+        }
+
+        ~writer()
+        {
+            if(file_)
+                fclose(file_);
+        }
+
+        void
+        init(error_code& ec) noexcept
+        {
+            file_ = fopen(path_.c_str(), "rb");
+            if(! file_)
+                ec = boost::system::errc::make_error_code(
+                    static_cast<boost::system::errc::errc_t>(errno));
+            else
+                size_ = boost::filesystem::file_size(path_);
+        }
+
+        auto
+        content_length() const
+        {
+            return size_;
+        }
+
+        template<class Write>
+        boost::tribool
+        operator()(resume_context&&, error_code&, Write&& write)
+        {
+            buf_len_ = std::min(size_ - offset_, sizeof(buf_));
+            fread(buf_, 1, sizeof(buf_), file_);
+            offset_ += buf_len_;
+            write(boost::asio::buffer(buf_, buf_len_));
+            return offset_ >= size_;
+        }
+    };
+};
+
+} // http
+} // beast
+
+#endif