boost/beast/http/fields.hpp
//
// Copyright (c) 2016-2019 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)
//
// Official repository: https://github.com/boostorg/beast
//
#ifndef BOOST_BEAST_HTTP_FIELDS_HPP
#define BOOST_BEAST_HTTP_FIELDS_HPP
#include <boost/beast/core/detail/config.hpp>
#include <boost/beast/core/string.hpp>
#include <boost/beast/core/detail/allocator.hpp>
#include <boost/beast/http/field.hpp>
#include <boost/asio/buffer.hpp>
#include <boost/core/empty_value.hpp>
#include <boost/intrusive/list.hpp>
#include <boost/intrusive/set.hpp>
#include <boost/optional.hpp>
#include <algorithm>
#include <cctype>
#include <cstring>
#include <memory>
#include <string>
#include <type_traits>
#include <utility>
namespace boost {
namespace beast {
namespace http {
/** A container for storing HTTP header fields.
This container is designed to store the field value pairs that make
up the fields and trailers in an HTTP message. Objects of this type
are iterable, with each element holding the field name and field
value.
Field names are stored as-is, but comparisons are case-insensitive.
The container behaves as a `std::multiset`; there will be a separate
value for each occurrence of the same field name. When the container
is iterated the fields are presented in the order of insertion, with
fields having the same name following each other consecutively.
Meets the requirements of <em>Fields</em>
@tparam Allocator The allocator to use.
*/
template<class Allocator>
class basic_fields
#if ! BOOST_BEAST_DOXYGEN
: private boost::empty_value<Allocator>
#endif
{
// Fancy pointers are not supported
static_assert(std::is_pointer<typename
std::allocator_traits<Allocator>::pointer>::value,
"Allocator must use regular pointers");
friend class fields_test; // for `header`
struct element;
using off_t = std::uint16_t;
public:
/// The type of allocator used.
using allocator_type = Allocator;
/// The type of element used to represent a field
class value_type
{
friend class basic_fields;
off_t off_;
off_t len_;
field f_;
char*
data() const;
net::const_buffer
buffer() const;
protected:
value_type(field name,
string_view sname, string_view value);
public:
/// Constructor (deleted)
value_type(value_type const&) = delete;
/// Assignment (deleted)
value_type& operator=(value_type const&) = delete;
/// Returns the field enum, which can be @ref field::unknown
field
name() const;
/// Returns the field name as a string
string_view const
name_string() const;
/// Returns the value of the field
string_view const
value() const;
};
/** A strictly less predicate for comparing keys, using a case-insensitive comparison.
The case-comparison operation is defined only for low-ASCII characters.
*/
#if BOOST_BEAST_DOXYGEN
using key_compare = __implementation_defined__;
#else
struct key_compare : beast::iless
#endif
{
/// Returns `true` if lhs is less than rhs using a strict ordering
bool
operator()(
string_view lhs,
value_type const& rhs) const noexcept
{
if(lhs.size() < rhs.name_string().size())
return true;
if(lhs.size() > rhs.name_string().size())
return false;
return iless::operator()(lhs, rhs.name_string());
}
/// Returns `true` if lhs is less than rhs using a strict ordering
bool
operator()(
value_type const& lhs,
string_view rhs) const noexcept
{
if(lhs.name_string().size() < rhs.size())
return true;
if(lhs.name_string().size() > rhs.size())
return false;
return iless::operator()(lhs.name_string(), rhs);
}
/// Returns `true` if lhs is less than rhs using a strict ordering
bool
operator()(
value_type const& lhs,
value_type const& rhs) const noexcept
{
if(lhs.name_string().size() < rhs.name_string().size())
return true;
if(lhs.name_string().size() > rhs.name_string().size())
return false;
return iless::operator()(lhs.name_string(), rhs.name_string());
}
};
/// The algorithm used to serialize the header
#if BOOST_BEAST_DOXYGEN
using writer = __implementation_defined__;
#else
class writer;
#endif
private:
struct element
: public boost::intrusive::list_base_hook<
boost::intrusive::link_mode<
boost::intrusive::normal_link>>
, public boost::intrusive::set_base_hook<
boost::intrusive::link_mode<
boost::intrusive::normal_link>>
, public value_type
{
element(field name,
string_view sname, string_view value);
};
using list_t = typename boost::intrusive::make_list<
element,
boost::intrusive::constant_time_size<false>
>::type;
using set_t = typename boost::intrusive::make_multiset<
element,
boost::intrusive::constant_time_size<true>,
boost::intrusive::compare<key_compare>
>::type;
using align_type = typename
boost::type_with_alignment<alignof(element)>::type;
using rebind_type = typename
beast::detail::allocator_traits<Allocator>::
template rebind_alloc<align_type>;
using alloc_traits =
beast::detail::allocator_traits<rebind_type>;
using size_type = typename
beast::detail::allocator_traits<Allocator>::size_type;
public:
/// Destructor
~basic_fields();
/// Constructor.
basic_fields() = default;
/** Constructor.
@param alloc The allocator to use.
*/
explicit
basic_fields(Allocator const& alloc) noexcept;
/** Move constructor.
The state of the moved-from object is
as if constructed using the same allocator.
*/
basic_fields(basic_fields&&) noexcept;
/** Move constructor.
The state of the moved-from object is
as if constructed using the same allocator.
@param alloc The allocator to use.
*/
basic_fields(basic_fields&&, Allocator const& alloc);
/// Copy constructor.
basic_fields(basic_fields const&);
/** Copy constructor.
@param alloc The allocator to use.
*/
basic_fields(basic_fields const&, Allocator const& alloc);
/// Copy constructor.
template<class OtherAlloc>
basic_fields(basic_fields<OtherAlloc> const&);
/** Copy constructor.
@param alloc The allocator to use.
*/
template<class OtherAlloc>
basic_fields(basic_fields<OtherAlloc> const&,
Allocator const& alloc);
/** Move assignment.
The state of the moved-from object is
as if constructed using the same allocator.
*/
basic_fields& operator=(basic_fields&&) noexcept(
alloc_traits::propagate_on_container_move_assignment::value);
/// Copy assignment.
basic_fields& operator=(basic_fields const&);
/// Copy assignment.
template<class OtherAlloc>
basic_fields& operator=(basic_fields<OtherAlloc> const&);
public:
/// A constant iterator to the field sequence.
#if BOOST_BEAST_DOXYGEN
using const_iterator = __implementation_defined__;
#else
using const_iterator = typename list_t::const_iterator;
#endif
/// A constant iterator to the field sequence.
using iterator = const_iterator;
/// Return a copy of the allocator associated with the container.
allocator_type
get_allocator() const
{
return this->get();
}
//--------------------------------------------------------------------------
//
// Element access
//
//--------------------------------------------------------------------------
/** Returns the value for a field, or throws an exception.
If more than one field with the specified name exists, the
first field defined by insertion order is returned.
@param name The name of the field.
@return The field value.
@throws std::out_of_range if the field is not found.
*/
string_view const
at(field name) const;
/** Returns the value for a field, or throws an exception.
If more than one field with the specified name exists, the
first field defined by insertion order is returned.
@param name The name of the field.
@return The field value.
@throws std::out_of_range if the field is not found.
*/
string_view const
at(string_view name) const;
/** Returns the value for a field, or `""` if it does not exist.
If more than one field with the specified name exists, the
first field defined by insertion order is returned.
@param name The name of the field.
*/
string_view const
operator[](field name) const;
/** Returns the value for a case-insensitive matching header, or `""` if it does not exist.
If more than one field with the specified name exists, the
first field defined by insertion order is returned.
@param name The name of the field.
*/
string_view const
operator[](string_view name) const;
//--------------------------------------------------------------------------
//
// Iterators
//
//--------------------------------------------------------------------------
/// Return a const iterator to the beginning of the field sequence.
const_iterator
begin() const
{
return list_.cbegin();
}
/// Return a const iterator to the end of the field sequence.
const_iterator
end() const
{
return list_.cend();
}
/// Return a const iterator to the beginning of the field sequence.
const_iterator
cbegin() const
{
return list_.cbegin();
}
/// Return a const iterator to the end of the field sequence.
const_iterator
cend() const
{
return list_.cend();
}
//--------------------------------------------------------------------------
//
// Capacity
//
//--------------------------------------------------------------------------
private:
// VFALCO Since the header and message derive from Fields,
// what does the expression m.empty() mean? Its confusing.
bool
empty() const
{
return list_.empty();
}
public:
//--------------------------------------------------------------------------
//
// Modifiers
//
//--------------------------------------------------------------------------
/** Remove all fields from the container
All references, pointers, or iterators referring to contained
elements are invalidated. All past-the-end iterators are also
invalidated.
@par Postconditions:
@code
std::distance(this->begin(), this->end()) == 0
@endcode
*/
void
clear();
/** Insert a field.
If one or more fields with the same name already exist,
the new field will be inserted after the last field with
the matching name, in serialization order.
@param name The field name.
@param value The value of the field, as a @ref string_view
*/
void
insert(field name, string_view const& value);
/* Set a field from a null pointer (deleted).
*/
void
insert(field, std::nullptr_t) = delete;
/** Insert a field.
If one or more fields with the same name already exist,
the new field will be inserted after the last field with
the matching name, in serialization order.
@param name The field name.
@param value The value of the field, as a @ref string_view
*/
void
insert(string_view name, string_view const& value);
/* Insert a field from a null pointer (deleted).
*/
void
insert(string_view, std::nullptr_t) = delete;
/** Insert a field.
If one or more fields with the same name already exist,
the new field will be inserted after the last field with
the matching name, in serialization order.
@param name The field name.
@param name_string The literal text corresponding to the
field name. If `name != field::unknown`, then this value
must be equal to `to_string(name)` using a case-insensitive
comparison, otherwise the behavior is undefined.
@param value The value of the field, as a @ref string_view
*/
void
insert(field name, string_view name_string,
string_view const& value);
void
insert(field, string_view, std::nullptr_t) = delete;
/** Set a field value, removing any other instances of that field.
First removes any values with matching field names, then
inserts the new field value.
@param name The field name.
@param value The value of the field, as a @ref string_view
@return The field value.
*/
void
set(field name, string_view const& value);
void
set(field, std::nullptr_t) = delete;
/** Set a field value, removing any other instances of that field.
First removes any values with matching field names, then
inserts the new field value.
@param name The field name.
@param value The value of the field, as a @ref string_view
*/
void
set(string_view name, string_view const& value);
void
set(string_view, std::nullptr_t) = delete;
/** Remove a field.
References and iterators to the erased elements are
invalidated. Other references and iterators are not
affected.
@param pos An iterator to the element to remove.
@return An iterator following the last removed element.
If the iterator refers to the last element, the end()
iterator is returned.
*/
const_iterator
erase(const_iterator pos);
/** Remove all fields with the specified name.
All fields with the same field name are erased from the
container.
References and iterators to the erased elements are
invalidated. Other references and iterators are not
affected.
@param name The field name.
@return The number of fields removed.
*/
std::size_t
erase(field name);
/** Remove all fields with the specified name.
All fields with the same field name are erased from the
container.
References and iterators to the erased elements are
invalidated. Other references and iterators are not
affected.
@param name The field name.
@return The number of fields removed.
*/
std::size_t
erase(string_view name);
/** Return a buffer sequence representing the trailers.
This function returns a buffer sequence holding the
serialized representation of the trailer fields promised
in the Accept field. Before calling this function the
Accept field must contain the exact trailer fields
desired. Each field must also exist.
*/
/// Swap this container with another
void
swap(basic_fields& other);
/// Swap two field containers
template<class Alloc>
friend
void
swap(basic_fields<Alloc>& lhs, basic_fields<Alloc>& rhs);
//--------------------------------------------------------------------------
//
// Lookup
//
//--------------------------------------------------------------------------
/** Return the number of fields with the specified name.
@param name The field name.
*/
std::size_t
count(field name) const;
/** Return the number of fields with the specified name.
@param name The field name.
*/
std::size_t
count(string_view name) const;
/** Returns an iterator to the case-insensitive matching field.
If more than one field with the specified name exists, the
first field defined by insertion order is returned.
@param name The field name.
@return An iterator to the matching field, or `end()` if
no match was found.
*/
const_iterator
find(field name) const;
/** Returns an iterator to the case-insensitive matching field name.
If more than one field with the specified name exists, the
first field defined by insertion order is returned.
@param name The field name.
@return An iterator to the matching field, or `end()` if
no match was found.
*/
const_iterator
find(string_view name) const;
/** Returns a range of iterators to the fields with the specified name.
@param name The field name.
@return A range of iterators to fields with the same name,
otherwise an empty range.
*/
std::pair<const_iterator, const_iterator>
equal_range(field name) const;
/** Returns a range of iterators to the fields with the specified name.
@param name The field name.
@return A range of iterators to fields with the same name,
otherwise an empty range.
*/
std::pair<const_iterator, const_iterator>
equal_range(string_view name) const;
//--------------------------------------------------------------------------
//
// Observers
//
//--------------------------------------------------------------------------
/// Returns a copy of the key comparison function
key_compare
key_comp() const
{
return key_compare{};
}
protected:
/** Returns the request-method string.
@note Only called for requests.
*/
string_view
get_method_impl() const;
/** Returns the request-target string.
@note Only called for requests.
*/
string_view
get_target_impl() const;
/** Returns the response reason-phrase string.
@note Only called for responses.
*/
string_view
get_reason_impl() const;
/** Returns the chunked Transfer-Encoding setting
*/
bool
get_chunked_impl() const;
/** Returns the keep-alive setting
*/
bool
get_keep_alive_impl(unsigned version) const;
/** Returns `true` if the Content-Length field is present.
*/
bool
has_content_length_impl() const;
/** Set or clear the method string.
@note Only called for requests.
*/
void
set_method_impl(string_view s);
/** Set or clear the target string.
@note Only called for requests.
*/
void
set_target_impl(string_view s);
/** Set or clear the reason string.
@note Only called for responses.
*/
void
set_reason_impl(string_view s);
/** Adjusts the chunked Transfer-Encoding value
*/
void
set_chunked_impl(bool value);
/** Sets or clears the Content-Length field
*/
void
set_content_length_impl(
boost::optional<std::uint64_t> const& value);
/** Adjusts the Connection field
*/
void
set_keep_alive_impl(
unsigned version, bool keep_alive);
private:
template<class OtherAlloc>
friend class basic_fields;
element&
new_element(field name,
string_view sname, string_view value);
void
delete_element(element& e);
void
set_element(element& e);
void
realloc_string(string_view& dest, string_view s);
void
realloc_target(
string_view& dest, string_view s);
template<class OtherAlloc>
void
copy_all(basic_fields<OtherAlloc> const&);
void
clear_all();
void
delete_list();
void
move_assign(basic_fields&, std::true_type);
void
move_assign(basic_fields&, std::false_type);
void
copy_assign(basic_fields const&, std::true_type);
void
copy_assign(basic_fields const&, std::false_type);
void
swap(basic_fields& other, std::true_type);
void
swap(basic_fields& other, std::false_type);
set_t set_;
list_t list_;
string_view method_;
string_view target_or_reason_;
};
/// A typical HTTP header fields container
using fields = basic_fields<std::allocator<char>>;
} // http
} // beast
} // boost
#include <boost/beast/http/impl/fields.hpp>
#endif