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diff --git a/ns/ext/state/state.ttl b/ns/ext/state/state.ttl deleted file mode 100644 index c79188e..0000000 --- a/ns/ext/state/state.ttl +++ /dev/null @@ -1,231 +0,0 @@ -# LV2 State Extension -# Copyright 2010-2011 David Robillard <d@drobilla.net> -# Copyright 2010 Leonard Ritter <paniq@paniq.org> -# -# 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. -# -# THIS 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. - -@prefix state: <http://lv2plug.in/ns/ext/state#> . -@prefix doap: <http://usefulinc.com/ns/doap#> . -@prefix foaf: <http://xmlns.com/foaf/0.1/> . -@prefix lv2: <http://lv2plug.in/ns/lv2core#> . -@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . -@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> . - -<http://lv2plug.in/ns/ext/state> - a lv2:Specification ; - doap:name "LV2 State" ; - doap:shortdesc "An interface for LV2 plugins to save and restore state." ; - doap:license <http://opensource.org/licenses/isc-license> ; - doap:release [ - doap:revision "0.2" ; - doap:created "2011-11-14" - ] ; - doap:developer [ - a foaf:Person ; - foaf:name "Leonard Ritter" ; - foaf:homepage <http://paniq.org> ; - ] ; - doap:maintainer [ - a foaf:Person ; - foaf:name "David Robillard" ; - foaf:homepage <http://drobilla.net/> ; - rdfs:seeAlso <http://drobilla.net/drobilla.rdf> - ] ; - lv2:documentation """ -<p>This extension provides a mechanism for plugins to save and restore state -across instances, allowing hosts to save, restore, clone, or take a snapshot of -a plugin instance's state at any point in time. The intention is for a plugin -instance's state to be <em>completely</em> described by port values (as with all -LV2 plugins) and a simple dictionary.</p> - -<p>The <q>state</q> described by this extension is conceptually a single -key/value dictionary, where keys are URIDs and values are type-tagged blobs of -any type. The plugin provides an LV2_State_Interface for working with this -state. To save or restore, the host calls LV2_State_Interface::save() or -LV2_State_Interface::restore(), passing a callback to be used for handling a -single key/value pair. The host is free to implement saving and restoring in -any way; the actual mechanism is completely abstract from the plugin's -perspective.</p> - -<p>Because state is a simple dictionary, hosts and plugins can work with it -easily from many languages and protocols. Keys are URIDs for performance -reasons as well as RDF compatibility, which makes it simple to serialise state -in many formats (e.g. any RDF syntax, JSON, XML, key/value databases such as -BDB, etc.). In particular, state can be elegantly described in a plugin's -Turtle description, which is useful for e.g. presets or default state. -Specific keys may be described in Turtle on the fly or in extensions, -allowing plugins to use common well-defined keys.</p> - -<p>This extension defines a conceptual model of state and a mechanism for -saving and restoring it, but no interface for manipulating it dynamically. -While no such mechanism is defined here, dynamic control of plugins SHOULD be -achieved by generic manipulations of the same conceptual state dictionary used -by this extension (e.g. <code>plugin->set(key, value)</code>). Accordingly, -plugins SHOULD use meaningful and well-defined keys wherever possible.</p> - -<p>In pseudo code, a typical use case in a plugin is:</p> -<pre class="c-code"> -#define NS_EG "http://example.org/" -#define NS_ATOM "http://lv2plug.in/ns/ext/atom#" - -LV2_Handle my_instantiate(...) -{ - MyPlugin* plugin = ...; - plugin->uris.atom_String = map_uri(NS_ATOM "String"); - plugin->uris.eg_greeting = map_uri(NS_EG "greeting"); - plugin->state.greeting = strdup("Hello"); - return plugin; -} - -void my_save(LV2_Handle instance, - LV2_State_Store_Function store, - void* handle, - uint32_t flags, - const LV2_Feature *const * features) - -{ - MyPlugin* plugin = (MyPlugin*)instance; - const char* greeting = plugin->state.greeting; - - store(handle, - plugin->uris.eg_greeting, - greeting, - strlen(greeting) + 1, - plugin->uris.atom_String, - LV2_STATE_IS_POD | LV2_STATE_IS_PORTABLE); -} - -void my_restore(LV2_Handle instance, - LV2_State_Retrieve_Function retrieve, - void* handle, - uint32_t flags, - const LV2_Feature *const * features) -{ - MyPlugin* plugin = (MyPlugin*)instance; - - size_t size; - uint32_t type; - uint32_t flags; - const char* greeting = retrieve(handle, - plugin->uris.eg_greeting, - &size, - &type, - &flags); - - if (greeting) { - free(plugin->state->greeting); - plugin->state->greeting = strdup(greeting); - } else { - plugin->state->greeting = strdup("Hello"); - } -} - -const void* my_extension_data(const char* uri) -{ - static const LV2_State_Interface state_iface = { my_save, my_restore }; - if (!strcmp(uri, LV2_STATE_INTERFACE_URI)) { - return &state_iface; - } -} -</pre> - -<p>Similarly, a typical use case in a host is:</p> -<pre class="c-code"> -int store_callback(void* handle, - uint32_t key, - const void* value, - size_t size, - uint32_t type, - uint32_t flags) -{ - if ((flags & LV2_STATE_IS_POD)) { - /* We only care about POD since we're keeping state in memory only. - If this was for disk or network storage/transmission, - LV2_STATE_IS_PORTABLE would have to be checked as well. - */ - Map* state_map = (Map*)handle; - state_map->insert(key, Value(copy(value), size, type, pod)); - return 0; - } else { - return 1; /* Non-POD events are unsupported. */ - } -} - -Map get_plugin_state(LV2_Handle instance) -{ - LV2_State* state = instance.extension_data("http://lv2plug.in/ns/ext/state"); - Map state_map; - /** Request a fast/native/POD save, since we're just copying in memory */ - state.save(instance, store_callback, &state_map, - LV2_STATE_IS_POD|LV2_STATE_IS_NATIVE); - return state_map; -} -</pre> -""" . - -state:Interface - a rdfs:Class ; - rdfs:subClassOf lv2:ExtensionData ; - lv2:documentation """ -<p>A structure (LV2_State_Interface) which contains functions to be called by -the host to save and restore state. In order to support this extension, the -plugin must return a valid LV2_State_Interface from -LV2_Descriptor::extension_data() when it is called with -LV2_STATE_INTERFACE_URI.</p> - -<p>The plugin data file should describe this like so:</p> -<pre class="turtle-code"> -@prefix state: <http://lv2plug.in/ns/ext/state#> . - -<plugin> - a lv2:Plugin ; - lv2:extensionData state:Interface . -</pre> -""" . - -state:InstanceState - a rdfs:Class ; - rdfs:label "Plugin Instance State" ; - rdfs:comment """ -This class is used to express a plugin instance's state in RDF. The key/value -properties of the instance form the predicate/object (respectively) of triples -with a state:InstanceState as the subject (see state:instanceState for an -example). This may be used wherever it is useful to express a plugin instance's -state in RDF (e.g. for serialisation, storing in a model, or transmitting over -a network). Note that this class is provided because it may be useful for -hosts, plugins, or extensions that work with instance state, but its use is not -required to support the LV2 State extension. -""" . - -state:instanceState - a rdf:Property ; - rdfs:range state:InstanceState ; - lv2:documentation """ -<p>Predicate to relate a plugin instance to an InstanceState. This may be used -wherever the state of a particular plugin instance needs to be represented. -Note that the domain of this property is unspecified, since LV2 does not define -any RDF class for plugin instance. This predicate may be used wherever it makes -sense to do so, e.g.:</p> -<pre class="turtle-code"> -@prefix eg: <http://example.org/> . - -<plugininstance> state:instanceState [ - eg:somekey "some value" ; - eg:someotherkey "some other value" ; - eg:favourite-number 2 -] . -</pre> -<p>Note that this property is provided because it may be useful for hosts, -plugins, or extensions that work with instance state, but its use is not -required to support the LV2 State extension.</p> -""" . |