defined match those defined in that Socket's protocol. Using such a generic handle decouples the
implementation parts using this handle from the other socket aspects (e.g. you may define a
generic socket handle for TCP based communication leaving the addressingPolicy undefined which
- makes your code independent of the type of addressing, IPv4 or IPv6).
+ makes your code independent of the type of addressing, IPv4 or IPv6).
+
+ This can be described as generalized compile-time polymorphism: A base class reference to some
+ derived class will only give access to a reduced interface (the base class interface) of a
+ class. The class still is of it's derived type (and inherently has the complete interface) but
+ only part of it is accessible via the base class reference. Likewise a generic handle (aka base
+ class reference) will only provide a reduced interface (aka base class interface) to the derived
+ class instance (aka socket).
\section over_protocol The Protocol Interface
The protocol interface is provided by a set of <em>protocol facets</em>. Each facet provides a
part of the interface. Whereas the policy interface is strictly defined (the number and type of
- policy axis is fixed and also the possible members provided by the policy interface is fixed),
+ policy axis is fixed and also the possible members provided by the policy interface are fixed),
the protocol interface is much more flexible. Any member needed to provide a complete API for
the specific protocol may be defined, the number and type of facets combined to provide the
complete interface is up to the Protocol implementor. This flexibility is necessary to provide a
However this flexibility comes at a cost: To access the protocol interface the user must know
the exact protocol of the socket. With other words, the protocol is only accessible if the
- handle you use is a protocol specific handle. A protocol specific Handle differs from a generic
- Handle in two ways: It always \e must have a complete policy and it has an additional reference
- to the protocol type of the socket. This reference gives access to the complete policy
+ handle you use is a <em>protocol specific</em> handle. A protocol specific Handle differs from a
+ generic Handle in two ways: It always has a complete policy and it knows the exact protocol type
+ of the socket (which generic handles don't). This allows to access to the complete protocol
interface.
\section over_impl Implementation of the Socket Libarary Structure
outside visible. The Handle is provided by a hierarchy of handle templates. Each Handle template
uses template arguments for the policy and/or protocol as needed (see \ref handle_group).
+ The Handle hierarchy divides the interface into two separate strains: the client interface
+ (senf::ClientSocketHandle and senf::ProtocolClientSocketHandle) provides the interface of a
+ client socket whereas the server interface (senf::ServerSocketHandle and
+ senf::ProtocolServerSocketHandle) provides the interface as used by server sockets.
+
The protocol interface is implemented using inheritance: The Protocol class inherits from each
protocol facet using multiple (virtual public) inheritance. The Protocol class therefore
provides the complete protocol API in a unified (see \ref protocol_group).
-
- The Handle references the policy and the protocol only via it's template argument, the
- information is part of the type. This information is not available as a data member in the
- Handle object.
*/
/** \page usage Using the Socket Library
template).
\see \ref extend_policy \n
- <a class="ext" href="http://www.boost.org/libs/utility/enable_if.html">The Boost enable_if utility</a> \n
- <a class="ext" href="http://www.boost.org/libs/mpl/doc/index.html">The Boost.MPL library</a> \n
- <a class="ext" href="http://www.boost.org/libs/preprocessor/doc/index.html">The Boost.Preprocessor library</a>
+ <a href="http://www.boost.org/libs/utility/enable_if.html">The Boost enable_if utility</a> \n
+ <a href="http://www.boost.org/libs/mpl/doc/index.html">The Boost.MPL library</a> \n
+ <a href="http://www.boost.org/libs/preprocessor/doc/index.html">The Boost.Preprocessor library</a>
\idea We could combine all the \e Axis \c Is templates into a single template. Since the \e
trait argument will automatically specify the axis to be used, it is not necessary to specify
/** \defgroup policy_impl_group Policy Implementation classes
\ingroup policy_group
- Here you will find all policy classes. Also included are some
- supporting classes which are used as base classes to build other
- policy classes.
+ Here you will find all policy classes. Also included are some supporting classes which are used
+ as base classes to build other policy classes.
*/
#ifndef HH_SocketPolicy_
\internal
- This define symbol is used to configure the policy axis. The
- base class for each of these axis must be defined explicitly
- (e.g. AddressingPolicyBase). The implementation files will
- then automatically generate all the other classes from this
- list.
+ This define symbol is used to configure the policy axis. The base class for each of these
+ axis must be defined explicitly (e.g. AddressingPolicyBase). The implementation files will
+ then automatically generate all the other classes from this list.
\see policy_group
*/
/** \brief Policy defining socket addressing
- AddressingPolicyBase is the baseclass of all addressing policy
- classes. When defining a new addressing policy, the following
- members can be defined. All methods must be static.
+ AddressingPolicyBase is the baseclass of all addressing policy classes. When defining a new
+ addressing policy, the following members can be defined. All methods must be static.
<table class="senf">
<tr><td>typedef</td> <td><tt>Address</tt></td> <td>Address type</td></tr>
/** \brief Policy defining the framing format
- This policy does not define any operations since it does have
- no influence on any method signature. It does however affect
- the semantics of the \c read() and \c write() operations.
+ This policy does not define any operations since it does have no influence on any method
+ signature. It does however affect the semantics of the \c read() and \c write() operations.
- \note This policy axis probably only has two sensible statess:
- StreamFramingPolicy and DatagramFramingPolicy.
+ \note This policy axis probably only has two sensible statess: StreamFramingPolicy and
+ DatagramFramingPolicy.
\see policy_group
*/
<tr><td>method</td> <td><tt>int accept(FileHandle, Address &)</tt></td> <td>Accept a new connection</td></tr>
</table>
- The \c listen member is straight forward. The \c accept() member
- must return a new file descriptor (which will be used to
- create a new SocketHandle of the correct type). Additionally,
- accept() should only be defined, if the Addressing policy is
- not \c NoAddressingPolicy (which together with
- ConnectedCommunicationPolicy would identify a point-to-point
- link with fixed communication partners).
+ The \c listen member is straight forward. The \c accept() member must return a new file
+ descriptor (which will be used to create a new SocketHandle of the correct
+ type). Additionally, accept() should only be defined, if the Addressing policy is not \c
+ NoAddressingPolicy (which together with ConnectedCommunicationPolicy would identify a
+ point-to-point link with fixed communication partners).
- \note This Policy only has two meaningful states:
- ConnectedCommunicationPolicy and
- UnconnectedCommunicationPolicy. It is probably not sensible to
- define a new CommunicationPolicy type.
+ \note This Policy only has two meaningful states: ConnectedCommunicationPolicy and
+ UnconnectedCommunicationPolicy. It is probably not sensible to define a new
+ CommunicationPolicy type.
\see policy_group
*/
/** \brief Policy defining the readability
- The ReadPolicy defines, wether the socket is readable. It
- may define two members:
+ The ReadPolicy defines, wether the socket is readable. It may define two members:
<table class="senf">
<tr><td>method</td> <td><tt>unsigned read(FileHandle, char * buffer, unsigned size)</tt></td> <td>read data from socket</td></tr>
<tr><td>method</td> <td><tt>unsigned readfrom(FileHandle, char * buffer, unsigned size, Address &)</tt></td> <td>read data from unconnected socket</td></tr>
</table>
- The second member should only be enabled if the communication
- policy is UnconnectedCommunication (otherwise it does not make
- sense since the communication partner is fixed) (see
- AddressingPolicyBase on how to do this).
+ The second member should only be enabled if the communication policy is
+ UnconnectedCommunication (otherwise it does not make sense since the communication partner
+ is fixed) (see AddressingPolicyBase on how to do this).
- \note This Policy only has two meaningful states:
- ReadablePolicy and NotReadablePolicy. It probably does not
- make sense to define new read policy types.
+ \note This Policy only has two meaningful states: ReadablePolicy and NotReadablePolicy. It
+ probably does not make sense to define new read policy types.
\see policy_group
*/
/** \brief Policy defining the writability
- The WritePolicy defines, wether the socket is writable. It may
- define two members:
+ The WritePolicy defines, wether the socket is writable. It may define two members:
<table class="senf">
<tr><td>method</td> <td><tt>unsigned write(FileHandle, char * buffer, unsigned size)</tt></td> <td>read data from socket</td></tr>
<tr><td>method</td> <td><tt>unsigned writeto(FileHandle, char * buffer, unsigned size, Address &)</tt></td> <td>read data from unconnected socket</td></tr>
</table>
- The second member should only be enabled if the communication
- policy is UnconnectedCommunication (otherwise it does not make
- sense since the communication partner is fixed) (see
- AddressingPolicyBase on how to do this).
+ The second member should only be enabled if the communication policy is
+ UnconnectedCommunication (otherwise it does not make sense since the communication partner
+ is fixed) (see AddressingPolicyBase on how to do this).
- \note This Policy only has two meaningful states:
- WritablePolicy and NotWritablePolicy. It probably does not
- make sense to define new write policy types.
+ \note This Policy only has two meaningful states: WritablePolicy and NotWritablePolicy. It
+ probably does not make sense to define new write policy types.
\see policy_group
*/
/** \brief Policy defining the buffering interface
- The BufferingPolicy defines the buffer handling of the
- socket. It may provide the follogin members:
+ The BufferingPolicy defines the buffer handling of the socket. It may provide the follogin
+ members:
\see policy_group
*/
/** \brief Check single policy axis
- This template is an example of the \e Axis \c Is family of
- tempalte metafunctions. It will check, wether \c Trait is a
- valid compatible Policy class of \c SocketPolicy. \c Trait
- must be derived from AddressingPolicyBase (respectively \i
- Policy \c Base).
+ This template is an example of the \e Axis \c Is family of tempalte metafunctions. It will
+ check, wether \c Trait is a valid compatible Policy class of \c SocketPolicy. \c Trait must
+ be derived from AddressingPolicyBase (respectively \i Policy \c Base).
\see \ref policy_group
*/
/** \brief Enable template overload depending on policy value
- This template is an exmaple of the \c If \e Axis \c Is
- family of templates. It is used like <a class="ext"
- href="http://www.boost.org/libs/utility/enable_if.html">Boost.enable_if</a>
- to enable a templated overload only, if the AddressingPolicy
- of \e Axis is compatible with \c Trait (that is the
- AddressingPolicy of \c Policy is derived from \c Trait).
+ This template is an exmaple of the \c If \e Axis \c Is family of templates. It is used like
+ <a href="http://www.boost.org/libs/utility/enable_if.html">Boost.enable_if</a> to enable a
+ templated overload only, if the AddressingPolicy of \e Axis is compatible with \c Trait
+ (that is the AddressingPolicy of \c Policy is derived from \c Trait).
\see policy_group
*/
\internal
- This class provides the baseclass of all socket policies
- (bundles). It serves two purposes:
- \li It allows us to easily identify a socket policy bundle by
- checking a classes baseclass.
- \li It provides an abstract (virtual) interface to access the
- policy axes
+ This class provides the baseclass of all socket policies (bundles). It serves two purposes:
+ \li It allows us to easily identify a socket policy bundle by checking a classes baseclass.
+ \li It provides an abstract (virtual) interface to access the policy axes
\see policy_group
*/
{
/** \brief Polymorphic access to policy axes
- This is an example of a policy axes accessor. It returns a
- reference to the policy axes used by the conrecte protocol
- bundle. This reference can then be checked using RTTI
+ This is an example of a policy axes accessor. It returns a reference to the policy axes
+ used by the conrecte protocol bundle. This reference can then be checked using RTTI
information.
*/
AddressingPolicyBase const & theAddressingPolicy() const = 0;
/** \brief Collection of policy classes
- The SocketPolicy template defines the complete Policy used by
- the socket library. It contains one policy class for each
- policy axis. This template takes one policy from each axis as
- it's template arguments (this example implementation only has
- AddressingPolicy as an argument).
+ The SocketPolicy template defines the complete Policy used by the socket library. It
+ contains one policy class for each policy axis. This template takes one policy from each
+ axis as it's template arguments (this example implementation only has AddressingPolicy as an
+ argument).
- A SocketPolicy can be complete or incomplete. An incomplete
- SocketPolicy will have at least one axis set to \c Undefined
- \e Axis (or a generic derived class which is used to group
- some other policies but does not (completely) define the
- policy behavior). A complete SocketPolicy will have a
- concrete definition of the desired behavior for each policy
- axis.
+ A SocketPolicy can be complete or incomplete. An incomplete SocketPolicy will have at least
+ one axis set to \c Undefined \e Axis (or a generic derived class which is used to group some
+ other policies but does not (completely) define the policy behavior). A complete
+ SocketPolicy will have a concrete definition of the desired behavior for each policy axis.
\see policy_group
*/
{
/** \brief Check dynamic policy compatibility
- This method will check the socket policy \a other against
- this policy. It will check, wether \a other is a base
- policy (or the same) of this policy. This check is done
- against the \e dynamic type of \a other using RTTI. It
- will throw \c std::bad_cast, if the policy is not
- compatible.
+ This method will check the socket policy \a other against this policy. It will check,
+ wether \a other is a base policy (or the same) of this policy. This check is done
+ against the \e dynamic type of \a other using RTTI. It will throw \c std::bad_cast, if
+ the policy is not compatible.
\param[in] other SocketPolicy to check
- \throws std::bad_cast if \a other is not a compatible
- policy
+ \throws std::bad_cast if \a other is not a compatible policy
*/
static void checkBaseOf(SocketPolicyBase const & other);
};
/** \brief Metafunction to create SocketPolicy
- This template metafunction simplifies the creation of a
- SocketPolicy instantiation. It takes any number (that is up to
- 6) of Policy classes as arguments in any Order. It will create
- a SocketPolicy from these policy classes. Any axis not
- specified will be left as \c Unspecified \e Axis.
+ This template metafunction simplifies the creation of a SocketPolicy instantiation. It takes
+ any number (that is up to 6) of Policy classes as arguments in any Order. It will create a
+ SocketPolicy from these policy classes. Any axis not specified will be left as \c
+ Unspecified \e Axis.
\see policy_group
*/
/** \brief Check policy compatibility
- This tempalte metafunction checks, wether the SocketPolicy \c
- Derived is more specialized than \c Base (and therefore a
- SocketHandle with policy \c Derived is convertible to a
+ This tempalte metafunction checks, wether the SocketPolicy \c Derived is more specialized
+ than \c Base (and therefore a SocketHandle with policy \c Derived is convertible to a
SocketHandle with policy \c Base).
- The metafunction will return true (that is inherits from \c
- boost::true_type, see the <a class="ext"
- href="http://www.boost.org/libs/mpl/doc/index.html">Boost.MPL</a>
- library documentation for more information) if each policy
- class in \c Base is a baseclass of (or the same as) the
+ The metafunction will return true (that is inherits from \c boost::true_type, see the <a
+ href="http://www.boost.org/libs/mpl/doc/index.html">Boost.MPL</a> library documentation for
+ more information) if each policy class in \c Base is a baseclass of (or the same as) the
corresponding policy class in \c Derived.
\see policy_group
projects / senf.git / commitdiff