boost_beast/include/beast/http/read.hpp

//
// Copyright (c) 2013-2016 Vinnie Falco (vinnie dot falco at gmail dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

#ifndef BEAST_HTTP_READ_HPP
#define BEAST_HTTP_READ_HPP

#include <beast/core/async_completion.hpp>
#include <beast/core/error.hpp>
#include <beast/http/message.hpp>

namespace beast {
namespace http {

/** Read a HTTP/1 header from a stream.

    This function is used to synchronously read a header
    from a stream. The call blocks until one of the following
    conditions is true:

    @li An entire header is read in.

    @li An error occurs in the stream or parser.

    This function is implemented in terms of one or more calls
    to the stream's `read_some` function. The implementation may
    read additional octets that lie past the end of the message
    fields being parsed. This additional data is stored in the
    stream buffer, which may be used in subsequent calls.

    If the message corresponding to the header being received
    contains a message body, it is the callers responsibility
    to cause the body to be read in before attempting to read
    the next message.

    @param stream The stream from which the data is to be read.
    The type must support the @b `SyncReadStream` concept.

    @param dynabuf A @b `DynamicBuffer` holding additional bytes
    read by the implementation from the stream. This is both
    an input and an output parameter; on entry, any data in the
    stream buffer's input sequence will be given to the parser
    first.

    @param msg An object used to store the header. Any contents
    will be overwritten. The type must support copy assignment
    or move assignment.

    @throws system_error Thrown on failure.
*/
template<class SyncReadStream, class DynamicBuffer,
    bool isRequest, class Fields>
void
read(SyncReadStream& stream, DynamicBuffer& dynabuf,
    header<isRequest, Fields>& msg);

/** Read a HTTP/1 header from a stream.

    This function is used to synchronously read a header
    from a stream. The call blocks until one of the following
    conditions is true:

    @li An entire header is read in.

    @li An error occurs in the stream or parser.

    This function is implemented in terms of one or more calls
    to the stream's `read_some` function. The implementation may
    read additional octets that lie past the end of the message
    fields being parsed. This additional data is stored in the
    stream buffer, which may be used in subsequent calls.

    If the message corresponding to the header being received
    contains a message body, it is the callers responsibility
    to cause the body to be read in before attempting to read
    the next message.

    @param stream The stream from which the data is to be read.
    The type must support the @b `SyncReadStream` concept.

    @param dynabuf A @b `DynamicBuffer` holding additional bytes
    read by the implementation from the stream. This is both
    an input and an output parameter; on entry, any data in the
    stream buffer's input sequence will be given to the parser
    first.

    @param msg An object used to store the header. Any contents
    will be overwritten. The type must support copy assignment
    or move assignment.

    @param ec Set to the error, if any occurred.
*/
template<class SyncReadStream, class DynamicBuffer,
    bool isRequest, class Fields>
void
read(SyncReadStream& stream, DynamicBuffer& dynabuf,
    header<isRequest, Fields>& msg,
        error_code& ec);

/** Read a HTTP/1 header asynchronously from a stream.

    This function is used to asynchronously read a header from
    a stream. The function call always returns immediately. The
    asynchronous operation will continue until one of the following
    conditions is true:

    @li An entire header is read in.

    @li An error occurs in the stream or parser.

    This operation is implemented in terms of one or more calls to
    the stream's `async_read_some` function, and is known as a
    <em>composed operation</em>. The program must ensure that the
    stream performs no other operations until this operation completes.
    The implementation may read additional octets that lie past the
    end of the message fields being parsed. This additional data is
    stored in the stream buffer, which may be used in subsequent calls.

    If the message corresponding to the header being received
    contains a message body, it is the callers responsibility
    to cause the body to be read in before attempting to read
    the next message.

    @param stream The stream to read the message from.
    The type must support the @b `AsyncReadStream` concept.

    @param dynabuf A @b `DynamicBuffer` holding additional bytes
    read by the implementation from the stream. This is both
    an input and an output parameter; on entry, any data in the
    stream buffer's input sequence will be given to the parser
    first.

    @param msg An object used to store the header. Any contents
    will be overwritten. The type must support copy assignment or
    move assignment. The object must remain valid at least until
    the completion handler is called; ownership is not transferred.

    @param handler The handler to be called when the operation
    completes. Copies will be made of the handler as required.
    The equivalent function signature of the handler must be:
    @code void handler(
        error_code const& error // result of operation
    ); @endcode
    Regardless of whether the asynchronous operation completes
    immediately or not, the handler will not be invoked from within
    this function. Invocation of the handler will be performed in a
    manner equivalent to using `boost::asio::io_service::post`.
*/
template<class AsyncReadStream, class DynamicBuffer,
    bool isRequest, class Body, class Fields,
        class ReadHandler>
#if GENERATING_DOCS
void_or_deduced
#else
typename async_completion<
    ReadHandler, void(error_code)>::result_type
#endif
async_read(AsyncReadStream& stream, DynamicBuffer& dynabuf,
    header<isRequest, Fields>& msg,
        ReadHandler&& handler);

/** Read a HTTP/1 message from a stream.

    This function is used to synchronously read a message from
    a stream. The call blocks until one of the following conditions
    is true:

    @li A complete message is read in.

    @li An error occurs in the stream or parser.

    This function is implemented in terms of one or more calls
    to the stream's `read_some` function. The implementation may
    read additional octets that lie past the end of the message
    being parsed. This additional data is stored in the stream
    buffer, which may be used in subsequent calls.

    @param stream The stream from which the data is to be read.
    The type must support the @b `SyncReadStream` concept.

    @param dynabuf A @b `DynamicBuffer` holding additional bytes
    read by the implementation from the stream. This is both
    an input and an output parameter; on entry, any data in the
    stream buffer's input sequence will be given to the parser
    first.

    @param msg An object used to store the message. Any
    contents will be overwritten. The type must support
    copy assignment or move assignment.

    @throws system_error Thrown on failure.
*/
template<class SyncReadStream, class DynamicBuffer,
    bool isRequest, class Body, class Fields>
void
read(SyncReadStream& stream, DynamicBuffer& dynabuf,
    message<isRequest, Body, Fields>& msg);

/** Read a HTTP/1 message from a stream.

    This function is used to synchronously read a message from
    a stream. The call blocks until one of the following conditions
    is true:

    @li A complete message is read in.

    @li An error occurs in the stream or parser.

    This function is implemented in terms of one or more calls
    to the stream's `read_some` function. The implementation may
    read additional octets that lie past the end of the message
    being parsed. This additional data is stored in the stream
    buffer, which may be used in subsequent calls.

    @param stream The stream from which the data is to be read.
    The type must support the @b `SyncReadStream` concept.

    @param dynabuf A @b `DynamicBuffer` holding additional bytes
    read by the implementation from the stream. This is both
    an input and an output parameter; on entry, any data in the
    stream buffer's input sequence will be given to the parser
    first.

    @param msg An object used to store the message. Any
    contents will be overwritten. The type must support
    copy assignment or move assignment.

    @param ec Set to the error, if any occurred.
*/
template<class SyncReadStream, class DynamicBuffer,
    bool isRequest, class Body, class Fields>
void
read(SyncReadStream& stream, DynamicBuffer& dynabuf,
    message<isRequest, Body, Fields>& msg,
        error_code& ec);

/** Read a HTTP/1 message asynchronously from a stream.

    This function is used to asynchronously read a message from
    a stream. The function call always returns immediately. The
    asynchronous operation will continue until one of the following
    conditions is true:

    @li A complete message is read in.

    @li An error occurs in the stream or parser.

    This operation is implemented in terms of one or more calls to
    the stream's `async_read_some` function, and is known as a
    <em>composed operation</em>. The program must ensure that the
    stream performs no other operations until this operation completes.
    The implementation may read additional octets that lie past the
    end of the message being parsed. This additional data is stored
    in the stream buffer, which may be used in subsequent calls.

    @param stream The stream to read the message from.
    The type must support the @b `AsyncReadStream` concept.

    @param dynabuf A @b `DynamicBuffer` holding additional bytes
    read by the implementation from the stream. This is both
    an input and an output parameter; on entry, any data in the
    stream buffer's input sequence will be given to the parser
    first.

    @param msg An object used to store the header. Any contents
    will be overwritten. The type must support copy assignment or
    move assignment. The object must remain valid at least until
    the completion handler is called; ownership is not transferred.

    @param handler The handler to be called when the operation
    completes. Copies will be made of the handler as required.
    The equivalent function signature of the handler must be:
    @code void handler(
        error_code const& error // result of operation
    ); @endcode
    Regardless of whether the asynchronous operation completes
    immediately or not, the handler will not be invoked from within
    this function. Invocation of the handler will be performed in a
    manner equivalent to using `boost::asio::io_service::post`.
*/
template<class AsyncReadStream, class DynamicBuffer,
    bool isRequest, class Body, class Fields,
        class ReadHandler>
#if GENERATING_DOCS
void_or_deduced
#else
typename async_completion<
    ReadHandler, void(error_code)>::result_type
#endif
async_read(AsyncReadStream& stream, DynamicBuffer& dynabuf,
    message<isRequest, Body, Fields>& msg,
        ReadHandler&& handler);

} // http
} // beast

#include <beast/http/impl/read.ipp>

#endif