328 lines
15 KiB
C
328 lines
15 KiB
C
/*
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interface.h - Lumiera interface macros and structures
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Copyright (C) Lumiera.org
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2008, Christian Thaeter <ct@pipapo.org>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#ifndef LUMIERA_INTERFACE_H
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#define LUMIERA_INTERFACE_H
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#include "lib/luid.h"
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#include "lib/ppmpl.h"
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/* TODO better doxygen formating */
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/**
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* @file
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* Lumiera interface macros and structures.
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*
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* Instead just simple function/library bindings, Lumiera uses a system of
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* versioned interfaces. This interfaces are C-binding compatible and thus
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* can be used by any language which can bind to C. This interfaces are versioned
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* to provide exceptional forward and backward compatibility for both, source and
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* binary deployment of modules. This interfaces play a central role on the Lumiera
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* architecture, other facilities, like serializing sessions and distributed computing
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* will use them extensively.
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*
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* Overview
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*
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* Interfaces are used for two purposes in Lumiera:
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* 1. The core uses them internally and exports its functionality though them.
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* 2. Plugins (effects,...) extend Lumiera by providing interfaces
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*
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* We define some macros here which ease the declaration and definition of interfaces.
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*
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* Declaration of an interface happens in a header and has the form:
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* LUMIERA_INTERFACE_DECLARE(name, version,
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* LUMIERA_INTERFACE_SLOT(ret, name, params),
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* ...
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* )
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* Any code which want to use this interface must then include its declaration.
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*
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* Basic definition of an interface is done by:
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* LUMIERA_INTERFACE_DEFINE(iname, version, name, descriptor, data, acquire, release,
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* LUMIERA_INTERFACE_DEFINE(iname, version, name, descriptor, data, acquire, release,
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* LUMIERA_INTERFACE_MAP (slot, function, luid),
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* ...
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* ),
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* ...
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* )
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*
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* There are 2 ways to define collections of interfaces:
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* LUMIERA_EXPORT(queryfunc,
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* LUMIERA_INTERFACE_DEFINE(...),
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* ...
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* )
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* to export interfaces from the core.
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*
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* LUMIERA_PLUGIN(descriptor, data, acquire, release, luid,
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* LUMIERA_INTERFACE_DEFINE(...),
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* ...
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* )
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* is used to export interfaces from a plugin.
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*
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* Naming and Versioning
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* Interfaces have unique names and a major and minor version. The name and the major version
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* is used to construct a C identifier for the interface, the minor version is implicit defined
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* by the number of functions a interface. Interface instances are not versioned by the
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* interface system, versioning these shall be defined somewhere else.
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*
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* Slot names are normal C identifiers, how these shall be versioned has to be defined somewhere
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* else and is not subject of the interface system. Each function can has its own unique uuid.
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*/
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/*
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Interface declaration macros
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*/
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/**
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* Construct a type identifier for an interface
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* @param name name of the interface
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* @param version major version of this interface
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*/
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#define LUMIERA_INTERFACE_INAME(name, version) lumiera_interface_##name##_##version
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/**
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* Construct a definition identifier for an interface
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* @param iname name of the interface
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* @param dname name for the instance
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* @param version major version of the interface
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*/
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#define LUMIERA_INTERFACE_DNAME(iname, dname, version) lumiera_##dname##_##version##_interface
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/**
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* Construct the type of the interface
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* @param name name of the interface
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* @param version major version of this interface
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*/
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#define LUMIERA_INTERFACE_TYPE(name, version) struct LUMIERA_INTERFACE_INAME(name, version)
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/**
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* Construct a cast to the target interface type
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* Used to cast a generic LumieraInterface to the real type
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* @param name name of the interface
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* @param version major version of this interface
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*/
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#define LUMIERA_INTERFACE_CAST(name, version) (LUMIERA_INTERFACE_TYPE(name, version)*)
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/**
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* Declare an interface.
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* @param name name of the interface
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* @param version major version of this interface declaration. 0 denotes a experimental interface,
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* otherwise this shall be counting from 1 upwards for each new (incompatible) change of an interface.
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* The older interface declarations may still be maintained in parallel (backwards compatibility!).
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* @param ... Slot declarations for the functions provided by this interface @see LUMIERA_INTERFACE_SLOT
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* The number of Slots in an interface defines its 'minor' version.
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* New slots must be added at the end. The prototype and order of existing slots must not be changed.
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* Slots may be renamed, for example a slot 'foo' can be renamed to 'foo_old' when a new 'foo' slot is
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* added. Binary modules will then still use the 'foo_old' slot which was the 'foo' slot at their
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* compile time while compiling modules from source will use the new 'foo' slot. This may be
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* intentionally used to break compilation and force the update of modules to a new api.
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*/
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#define LUMIERA_INTERFACE_DECLARE(name, version, ...) \
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LUMIERA_INTERFACE_TYPE(name, version) \
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{ \
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lumiera_interface interface_header_; \
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PPMPL_FOREACH(_, __VA_ARGS__) \
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}
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/**
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* Declare function slot inside an interface.
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* @param ret return type of the function
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* @param name name of this slot
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* @param params parentized list of parameters for the function
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*/
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#define LUMIERA_INTERFACE_SLOT(ret, name, params) ret (*name) params; lumiera_uid name##_uid;
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#define PPMPL_FOREACH_LUMIERA_INTERFACE_SLOT(ret, name, params) LUMIERA_INTERFACE_SLOT(ret, name, params)
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/*
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Interface definition macros
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*/
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/**
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* Define a interface instance.
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* @param iname name of the interface to instance
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* @param version major version of the interface to instance
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* @param name name of the instance
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* @param descriptor pointer to an interface instance which provides a description of this interface, might be NULL
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* @param data a opaque void* pointer which is passed to the implementation
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* @param acquire a function which is called whenever this interface is opened for using, might be NULL
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* @param release a function which is called whenever this interface is closed after use, might be NULL
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* @param ... map functions to interface slots @see LUMIERA_INTERFACE_MAP
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*/
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#define LUMIERA_INTERFACE_DEFINE(iname, version, name, descriptor, data, acquire, release, ...) \
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LUMIERA_INTERFACE_TYPE(iname, version) LUMIERA_INTERFACE_DNAME(iname, name, version) = \
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{ \
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{ \
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#name, \
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version, \
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sizeof (LUMIERA_INTERFACE_TYPE(iname, version)), \
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descriptor, \
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data, \
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acquire, \
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release \
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}, \
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PPMPL_FOREACH(_, __VA_ARGS__) \
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}
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/**
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* Map a function to a interface slot
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* @param slot name of the slot to be mapped
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* @param function name of the function to be mapped on slot
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* @param luid unique identifier for this function, use the magic word LUIDGEN here and run the
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* lumiera uuid generator tool (to be written) over the source file to generate luid's automatically
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*
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* @note C++ requires that all mappings are in the same order than defined in the interface declaration,
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* this would be good style for C too anyways
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*/
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#ifdef __cplusplus
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#define LUMIERA_INTERFACE_MAP(slot, function, luid) \
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function, LUMIERA_UID_INITIALIZER (uid),
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#else
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#define LUMIERA_INTERFACE_MAP(slot, function, luid) \
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.slot = function, .slot##_uid = LUMIERA_UID_INITIALIZER (luid),
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#endif
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#define PPMPL_FOREACH_LUMIERA_INTERFACE_MAP(slot, function, luid) LUMIERA_INTERFACE_MAP(slot, function, luid)
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#define PPMPL_FOREACH_L1_P1_LUMIERA_INTERFACE_DEFINE(iname, version, name, descriptor, data, acquire, release, ...) \
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LUMIERA_INTERFACE_DEFINE (iname, version, \
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name, \
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descriptor, \
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data, \
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acquire, \
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release, \
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__VA_ARGS__ \
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);
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#define PPMPL_FOREACH_L1_P2_LUMIERA_INTERFACE_DEFINE(iname, version, name, descriptor, data, acquire, release, ...) \
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&LUMIERA_INTERFACE_DNAME(iname, name, version).interface_header_,
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/**
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* Generate interface container suitable for enumerating interfaces.
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* This takes a list of interface definitions, instantiates them and places pointers to them
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* into a zero terminated array which address is returned by the a created function.
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* For interfaces generated by he core, the user is responsible to register these at the
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* plugindb dynamically
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* @param queryfunc name of the function to be created.
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* @param ... list of LUMIERA_INTERFACE_DEFINE() for all interfaces this plugin provides.
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*/
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#define LUMIERA_EXPORT(queryfunc, ...) \
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PPMPL_FOREACH_L1(_P1_, __VA_ARGS__) \
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static const LumieraInterface* \
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queryfunc (void) \
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{ \
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static const LumieraInterface interfaces[] = \
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{ \
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PPMPL_FOREACH_L1(_P2_, __VA_ARGS__) \
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NULL \
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}; \
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return interfaces; \
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} \
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/**
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* Generate interface container suitable for a lumiera plugin.
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* This takes a list of interface definitions and places pointers to them into a zero terminated array. Further
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* it instances a local 'plugin interface' which will be picked up by the plugin loader to query the array of
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* provided interfaces.
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* @param descriptor pointer to an interface instance which provides a description of this plugin, might be NULL
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* @param data a opaque void* pointer which is passed to the implementation
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* @param acquire a function which is called whenever the plugin interface is opened for using, might be NULL
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* @param release a function which is called whenever this plugin interface is closed after use, might be NULL
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* @param luid unique identifier for the this plugin interfaces query, use the magic word LUIDGEN here and run the
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* lumiera uuid generator tool (to be written) over the source file to generate luid's automatically
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* @param ... list of LUMIERA_INTERFACE_DEFINE() for all interfaces this plugin provides.
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*/
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#define LUMIERA_PLUGIN(descriptor, data, acquire, release, luid, ...) \
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LUMIERA_EXPORT(plugin_interfaces, __VA_ARGS__) \
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LUMIERA_INTERFACE_DEFINE (plugin, 0, \
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lumiera_plugin, \
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NULL, \
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NULL, \
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NULL, \
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NULL, \
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LUMIERA_INTERFACE_MAP (plugin_interfaces, plugin_interfaces, luid) \
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)
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typedef struct lumiera_interfaceslot_struct lumiera_interfaceslot;
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typedef lumiera_interfaceslot* LumieraInterfaceslot;
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typedef struct lumiera_interface_struct lumiera_interface;
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typedef lumiera_interface* LumieraInterface;
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/**
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* This is just a placeholder for an entry in a interface table.
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* It consists of one here generic, later correctly prototyped function pointer and
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* a unique identifier which is associated with this function.
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*/
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struct lumiera_interfaceslot_struct
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{
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void (*func)(void);
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lumiera_uid uid;
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};
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/**
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* Header for an interface, just the absolute necessary metadata.
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*/
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struct lumiera_interface_struct
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{
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/** name of the interface */
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const char* name;
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/** major version, 0 means experimental */
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unsigned version;
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/** size of the whole interface structure (minor version) */
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size_t size;
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/** metadata descriptor, itself a interface (or NULL) */
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LumieraInterface descriptor;
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/** generic data to be used by the implementation */
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void* data;
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/** must be called before this interface is used, might be nested */
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LumieraInterface (*acquire)(LumieraInterface self);
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/** called when finished with this interface, must match the acquire calls */
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void (*release)(LumieraInterface self);
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#ifndef __cplusplus
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/** placeholder array for the following function slots, C++ doesn't support flexible arrays */
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lumiera_interfaceslot functions[];
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#endif
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};
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#endif /* LUMIERA_INTERFACE_H */
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/*
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// Local Variables:
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// mode: C
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// c-file-style: "gnu"
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// indent-tabs-mode: nil
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// End:
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*/
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