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diff --git a/lv2/ns/ext/state/state.ttl b/lv2/ns/ext/state/state.ttl deleted file mode 100644 index 6c0656a..0000000 --- a/lv2/ns/ext/state/state.ttl +++ /dev/null @@ -1,359 +0,0 @@ -# LV2 State Extension -# Copyright 2010-2012 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 dcs: <http://ontologi.es/doap-changeset#> . -@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#> . -@prefix state: <http://lv2plug.in/ns/ext/state#> . - -<http://drobilla.net/drobilla#me> - a foaf:Person ; - foaf:name "David Robillard" ; - foaf:homepage <http://drobilla.net/> ; - foaf:mbox <mailto:d@drobilla.net> ; - rdfs:seeAlso <http://drobilla.net/drobilla> . - -<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> ; - doap:release [ - doap:revision "0.5" ; - doap:created "2012-01-29" ; - dcs:blame <http://drobilla.net/drobilla#me> - ] ; - 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 simple mechanism for plugins to save and restore -state across instances, allowing hosts to save and restore a plugin instance's -state at any time. The goal is for an instance's state to be -<em>completely</em> described by port values (as with all LV2 plugins) and a -dictionary.</p> - -<p>The <q>state</q> described by this extension is conceptually a simple -key:value dictionary, where keys are URIDs (URIs mapped to integers) and values -are type-tagged blobs of any type. A single key:value pair is called a -<q>property</q>. To implement state, the plugin provides a state:Interface to -the host. 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 property. The host is free to implement property storage and retrieval -in any way.</p> - -<p>This state model is simple yet has many benefits:</p> -<ul> - <li>URID keys provide both fast performance and RDF compatibility.</li> - <li>Fully extensible, no limitations on keys or value types.</li> - <li>Easy to serialise in many formats (e.g. any RDF syntax, plain - text, JSON, XML, key:value databases, SQL, s-expressions, etc.).</li> - <li>Elegantly described in Turtle, which is useful for describing presets - or default state in LV2 data files (the predicate state:state is provided - for this purpose).</li> - <li>Does not impose any file formats, data structures, or file system - requirements.</li> - <li>Suitable for portable persistent state as well as fast in-memory - snapshots.</li> - <li>Easily stored in a typical <q>map</q> or <q>dictionary</q> data - structure.</li> - <li>Keys may be defined by extensions and used by several plugins, - making state meaningful enabling dynamic state control.</li> -</ul> - -<p>Implementations or further extensions which work with plugin state -(including dynamic plugin control) SHOULD work entirely within this model. -That is, <strong>do not complicate the state model</strong>. <em>All</em> -information required to express an instance's state at any given time can, and -should, be expressed within this model.</p> - -<h3>Plugin Code Example</h3> - -<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> - -<h3>Host Code Example</h3> - -<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> - -<h3>Referring to Existing Files</h3> - -<p>Plugins may need to refer to files (e.g. loaded samples) in their state. -This is done by storing the file's path as a property just like any other -value. However, there are some rules which MUST be followed when storing -paths, see <a href="#mapPath">state:mapPath</a> for details.</p> - -<h3>Creating New Files or Directories</h3> - -<p>Implementations are strongly encouraged to avoid the use of files and simply -store all state as properties whenever possible. However, occasionally the -ability to create files is necessary. The feature <a -href="#newPath">state:newPath</a> makes this possible, if it is provided by the -host.</p> -""" . - -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:State - a rdfs:Class ; - rdfs:label "Plugin Instance State" ; - lv2:documentation """ -<p>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:State as the subject (see <a -href="#state">state:state</a> 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.</p> -""" . - -state:state - a rdf:Property ; - rdfs:range state:State ; - lv2:documentation """ -<p>Predicate to relate a plugin instance to its State. 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:state [ - 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 this extension.</p> -""" . - -state:mapPath - a lv2:Feature ; - rdfs:label "Support for storing paths in files" ; - lv2:documentation """ - -<p>This feature maps absolute paths to/from <q>abstract paths</q> which are -stored in state. To support this feature a host must pass an LV2_Feature with -URI LV2_STATE_MAP_PATH_URI and data pointed to an LV2_State_Map_Path to the -plugin's LV2_State_Interface methods.</p> - -<p>The plugin MUST map <em>all</em> paths stored in its state (including in any -files in its state). This is necessary to enable host to handle file system -references correctly, e.g. for distribution or archival.</p> - -<p>For example, a plugin may write a path to a state file like so:</p> - -<pre class="c-code"> -void write_path(LV2_State_Map_Path* map_path, FILE* myfile, const char* path) -{ - char* abstract_path = map_path->abstract_path(map_path->handle, path); - fprintf(myfile, "%s", abstract_path); - free(abstract_path); -} -</pre> - -<p>Then, later reload the path like so:</p> - -<pre class="c-code"> -char* read_path(LV2_State_Map_Path* map_path, FILE* myfile) -{ - /* Obviously this is not production quality code! */ - char abstract_path[1024]; - fscanf(myfile, "%s", abstract_path); - return map_path->absolute_path(map_path->handle, abstract_path); -} -</pre> -""" . - -state:makePath - a lv2:Feature ; - rdfs:label "Support for creating new files and directories" ; - lv2:documentation """ - -<p>This feature allows plugins to create new files and/or directories. To -support this feature the host passes an LV2_Feature with URI -LV2_STATE_MAKE_PATH_URI and data pointed to an LV2_State_Make_Path to the -plugin. The host may make this feature available only during save by passing -it to LV2_State_Interface::save(), or available any time by passing it to -LV2_Descriptor::instantiate(). If passed to LV2_State_Interface::save(), the -feature MUST NOT be used beyond the scope of that call.</p> - -<p>The plugin is guaranteed a hierarchial namespace unique to that plugin -instance, and may expect the returned path to have the requested path as a -suffix. There is <em>one</em> such namespace, even if the feature is passed to -both LV2_Descriptor::instantiate() <em>and</em> -LV2_State_Interface::save(). Beyond this, the plugin MUST NOT make any -assumptions about the returned paths.</p> - -<p>Like any other paths, the plugin MUST map these paths using <a -href="#mapPath">state:mapPath</a> before storing them in state. The plugin -MUST NOT assume these paths will be available across a save/restore otherwise, -i.e. only mapped paths saved to state are persistent, any other created paths -are temporary.</p> - -<p>For example, a plugin may create a file in a subdirectory like so:</p> - -<pre class="c-code"> -char* save_myfile(LV2_State_Make_Path* make_path) -{ - char* path = make_path->path(make_path->handle, "foo/bar/myfile.txt"); - FILE* myfile = fopen(path, 'w'); - fprintf(myfile, "Hello"); - fclose(myfile); - return path; -} -</pre> -""" . - -state:Path - a rdfs:Class ; - rdfs:label "Path" ; - lv2:documentation """ -<p>A path to a file or directory.</p> - -<p>The format of a state:Path is a C string, possibly escaped or otherwise -restricted in a system-specific manner. This URI (LV2_STATE_PATH_URI), mapped -to an integer, MUST be used as the <code>type</code> parameter for any files -passed to the LV2_State_Store_Function; and will likewise be returned by the -corresponding call to the LV2_State_Retrieve_Function.</p> - -<p>When storing and retrieving a path, the plugin MUST NOT assume the same path -will be restored. However, the restored path will refer to a file with -equivalent contents to the original.</p> -""" . |