Move headers to a conventional "include" directory

1 files changed, 1869 insertions, 0 deletions

diff --git a/include/lilv/lilv.h b/include/lilv/lilv.h
new file mode 100644
index 0000000..8c9ee22
--- /dev/null
+++ b/include/lilv/lilv.h
@@ -0,0 +1,1869 @@
+/*
+  Copyright 2007-2019 David Robillard <http://drobilla.net>
+
+  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.
+*/
+
+/**
+   @file lilv.h API for Lilv, a lightweight LV2 host library.
+*/
+
+#ifndef LILV_LILV_H
+#define LILV_LILV_H
+
+#include "lv2/core/lv2.h"
+#include "lv2/urid/urid.h"
+
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#ifdef LILV_SHARED
+#    ifdef _WIN32
+#        define LILV_LIB_IMPORT __declspec(dllimport)
+#        define LILV_LIB_EXPORT __declspec(dllexport)
+#    else
+#        define LILV_LIB_IMPORT __attribute__((visibility("default")))
+#        define LILV_LIB_EXPORT __attribute__((visibility("default")))
+#    endif
+#    ifdef LILV_INTERNAL
+#        define LILV_API LILV_LIB_EXPORT
+#    else
+#        define LILV_API LILV_LIB_IMPORT
+#    endif
+#else
+#    define LILV_API
+#endif
+#if defined(__GNUC__) && (__GNUC__ > 3 || \
+                          (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))
+#    define LILV_DEPRECATED __attribute__((__deprecated__))
+#else
+#    define LILV_DEPRECATED
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#    if defined(__clang__)
+#        pragma clang diagnostic push
+#        pragma clang diagnostic ignored "-Wzero-as-null-pointer-constant"
+#    endif
+#endif
+
+#define LILV_NS_DOAP "http://usefulinc.com/ns/doap#"
+#define LILV_NS_FOAF "http://xmlns.com/foaf/0.1/"
+#define LILV_NS_LILV "http://drobilla.net/ns/lilv#"
+#define LILV_NS_LV2  "http://lv2plug.in/ns/lv2core#"
+#define LILV_NS_OWL  "http://www.w3.org/2002/07/owl#"
+#define LILV_NS_RDF  "http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+#define LILV_NS_RDFS "http://www.w3.org/2000/01/rdf-schema#"
+#define LILV_NS_XSD  "http://www.w3.org/2001/XMLSchema#"
+
+#define LILV_URI_ATOM_PORT    "http://lv2plug.in/ns/ext/atom#AtomPort"
+#define LILV_URI_AUDIO_PORT   "http://lv2plug.in/ns/lv2core#AudioPort"
+#define LILV_URI_CONTROL_PORT "http://lv2plug.in/ns/lv2core#ControlPort"
+#define LILV_URI_CV_PORT      "http://lv2plug.in/ns/lv2core#CVPort"
+#define LILV_URI_EVENT_PORT   "http://lv2plug.in/ns/ext/event#EventPort"
+#define LILV_URI_INPUT_PORT   "http://lv2plug.in/ns/lv2core#InputPort"
+#define LILV_URI_MIDI_EVENT   "http://lv2plug.in/ns/ext/midi#MidiEvent"
+#define LILV_URI_OUTPUT_PORT  "http://lv2plug.in/ns/lv2core#OutputPort"
+#define LILV_URI_PORT         "http://lv2plug.in/ns/lv2core#Port"
+
+struct LilvInstanceImpl;
+
+typedef struct LilvPluginImpl      LilvPlugin;       /**< LV2 Plugin. */
+typedef struct LilvPluginClassImpl LilvPluginClass;  /**< Plugin Class. */
+typedef struct LilvPortImpl        LilvPort;         /**< Port. */
+typedef struct LilvScalePointImpl  LilvScalePoint;   /**< Scale Point. */
+typedef struct LilvUIImpl          LilvUI;           /**< Plugin UI. */
+typedef struct LilvNodeImpl        LilvNode;         /**< Typed Value. */
+typedef struct LilvWorldImpl       LilvWorld;        /**< Lilv World. */
+typedef struct LilvInstanceImpl    LilvInstance;     /**< Plugin instance. */
+typedef struct LilvStateImpl       LilvState;        /**< Plugin state. */
+
+typedef void LilvIter;           /**< Collection iterator */
+typedef void LilvPluginClasses;  /**< set<PluginClass>. */
+typedef void LilvPlugins;        /**< set<Plugin>. */
+typedef void LilvScalePoints;    /**< set<ScalePoint>. */
+typedef void LilvUIs;            /**< set<UI>. */
+typedef void LilvNodes;          /**< set<Node>. */
+
+/**
+   @defgroup lilv Lilv
+
+   A library for discovering and using LV2 plugins.
+
+   For more information about LV2, see <http://lv2plug.in/>.
+
+   @{
+*/
+
+/**
+   Free memory allocated by Lilv.
+
+   This function exists because some systems require memory allocated by a
+   library to be freed by code in the same library.  It is otherwise equivalent
+   to the standard C free() function.
+*/
+LILV_API void
+lilv_free(void* ptr);
+
+/**
+   @name Node
+   @{
+*/
+
+/**
+   Convert a file URI string to a local path string.
+   For example, "file://foo/bar/baz.ttl" returns "/foo/bar/baz.ttl".
+   Return value is shared and must not be deleted by caller.
+   This function does not handle escaping correctly and should not be used for
+   general file URIs.  Use lilv_file_uri_parse() instead.
+   @return `uri` converted to a path, or NULL on failure (URI is not local).
+*/
+LILV_API LILV_DEPRECATED const char*
+lilv_uri_to_path(const char* uri);
+
+/**
+   Convert a file URI string to a local path string.
+   For example, "file://foo/bar%20one/baz.ttl" returns "/foo/bar one/baz.ttl".
+   Return value must be freed by caller with lilv_free().
+   @param uri The file URI to parse.
+   @param hostname If non-NULL, set to the hostname in the URI, if any.
+   @return `uri` converted to a path, or NULL on failure (URI is not local).
+*/
+LILV_API char*
+lilv_file_uri_parse(const char* uri, char** hostname);
+
+/**
+   Create a new URI value.
+   Returned value must be freed by caller with lilv_node_free().
+*/
+LILV_API LilvNode*
+lilv_new_uri(LilvWorld* world, const char* uri);
+
+/**
+   Create a new file URI value.
+   @param world The world.
+   @param host Host name, or NULL.
+   @param path Path on host.
+   @return A new node that must be freed by caller.
+
+   Relative paths are resolved against the current working directory.  Note
+   that this may yield unexpected results if `host` is another machine.
+*/
+LILV_API LilvNode*
+lilv_new_file_uri(LilvWorld* world, const char* host, const char* path);
+
+/**
+   Create a new string value (with no language).
+   Returned value must be freed by caller with lilv_node_free().
+*/
+LILV_API LilvNode*
+lilv_new_string(LilvWorld* world, const char* str);
+
+/**
+   Create a new integer value.
+   Returned value must be freed by caller with lilv_node_free().
+*/
+LILV_API LilvNode*
+lilv_new_int(LilvWorld* world, int val);
+
+/**
+   Create a new floating point value.
+   Returned value must be freed by caller with lilv_node_free().
+*/
+LILV_API LilvNode*
+lilv_new_float(LilvWorld* world, float val);
+
+/**
+   Create a new boolean value.
+   Returned value must be freed by caller with lilv_node_free().
+*/
+LILV_API LilvNode*
+lilv_new_bool(LilvWorld* world, bool val);
+
+/**
+   Free a LilvNode.
+   It is safe to call this function on NULL.
+*/
+LILV_API void
+lilv_node_free(LilvNode* val);
+
+/**
+   Duplicate a LilvNode.
+*/
+LILV_API LilvNode*
+lilv_node_duplicate(const LilvNode* val);
+
+/**
+   Return whether two values are equivalent.
+*/
+LILV_API bool
+lilv_node_equals(const LilvNode* value, const LilvNode* other);
+
+/**
+   Return this value as a Turtle/SPARQL token.
+   Returned value must be freed by caller with lilv_free().
+   <table>
+   <caption>Example Turtle Tokens</caption>
+   <tr><th>URI</th><td>&lt;http://example.org/foo &gt;</td></tr>
+   <tr><th>QName</th><td>doap:name</td></tr>
+   <tr><th>String</th><td>"this is a string"</td></tr>
+   <tr><th>Float</th><td>1.0</td></tr>
+   <tr><th>Integer</th><td>1</td></tr>
+   <tr><th>Boolean</th><td>true</td></tr>
+   </table>
+*/
+LILV_API char*
+lilv_node_get_turtle_token(const LilvNode* value);
+
+/**
+   Return whether the value is a URI (resource).
+*/
+LILV_API bool
+lilv_node_is_uri(const LilvNode* value);
+
+/**
+   Return this value as a URI string, e.g. "http://example.org/foo".
+   Valid to call only if `lilv_node_is_uri(value)` returns true.
+   Returned value is owned by `value` and must not be freed by caller.
+*/
+LILV_API const char*
+lilv_node_as_uri(const LilvNode* value);
+
+/**
+   Return whether the value is a blank node (resource with no URI).
+*/
+LILV_API bool
+lilv_node_is_blank(const LilvNode* value);
+
+/**
+   Return this value as a blank node identifier, e.g. "genid03".
+   Valid to call only if `lilv_node_is_blank(value)` returns true.
+   Returned value is owned by `value` and must not be freed by caller.
+*/
+LILV_API const char*
+lilv_node_as_blank(const LilvNode* value);
+
+/**
+   Return whether this value is a literal (i.e. not a URI).
+   Returns true if `value` is a string or numeric value.
+*/
+LILV_API bool
+lilv_node_is_literal(const LilvNode* value);
+
+/**
+   Return whether this value is a string literal.
+   Returns true if `value` is a string value (and not numeric).
+*/
+LILV_API bool
+lilv_node_is_string(const LilvNode* value);
+
+/**
+   Return `value` as a string.
+*/
+LILV_API const char*
+lilv_node_as_string(const LilvNode* value);
+
+/**
+   Return the path of a file URI node.
+   Returns NULL if `value` is not a file URI.
+   Returned value must be freed by caller with lilv_free().
+*/
+LILV_API char*
+lilv_node_get_path(const LilvNode* value, char** hostname);
+
+/**
+   Return whether this value is a decimal literal.
+*/
+LILV_API bool
+lilv_node_is_float(const LilvNode* value);
+
+/**
+   Return `value` as a float.
+   Valid to call only if `lilv_node_is_float(value)` or
+   `lilv_node_is_int(value)` returns true.
+*/
+LILV_API float
+lilv_node_as_float(const LilvNode* value);
+
+/**
+   Return whether this value is an integer literal.
+*/
+LILV_API bool
+lilv_node_is_int(const LilvNode* value);
+
+/**
+   Return `value` as an integer.
+   Valid to call only if `lilv_node_is_int(value)` returns true.
+*/
+LILV_API int
+lilv_node_as_int(const LilvNode* value);
+
+/**
+   Return whether this value is a boolean.
+*/
+LILV_API bool
+lilv_node_is_bool(const LilvNode* value);
+
+/**
+   Return `value` as a bool.
+   Valid to call only if `lilv_node_is_bool(value)` returns true.
+*/
+LILV_API bool
+lilv_node_as_bool(const LilvNode* value);
+
+/**
+   @}
+   @name Collections
+   Lilv has several collection types for holding various types of value:
+   <ul>
+   <li>LilvPlugins (function prefix "lilv_plugins_")</li>
+   <li>LilvPluginClasses (function prefix "lilv_plugin_classes_")</li>
+   <li>LilvScalePoints (function prefix "lilv_scale_points_")</li>
+   <li>LilvNodes (function prefix "lilv_nodes_")</li>
+   <li>LilvUIs (function prefix "lilv_uis_")</li>
+   </ul>
+
+   Each collection type supports a similar basic API (except LilvPlugins which
+   is internal and thus lacks a free function):
+   <ul>
+   <li>void PREFIX_free (coll)</li>
+   <li>unsigned PREFIX_size (coll)</li>
+   <li>LilvIter* PREFIX_begin (coll)</li>
+   </ul>
+   @{
+*/
+
+/* Collections */
+
+/**
+   Iterate over each element of a collection.
+   @code
+   LILV_FOREACH(plugin_classes, i, classes) {
+      LilvPluginClass c = lilv_plugin_classes_get(classes, i);
+      // ...
+   }
+   @endcode
+*/
+#define LILV_FOREACH(colltype, iter, collection) \
+	for (LilvIter* iter = lilv_ ## colltype ## _begin(collection); \
+	     !lilv_ ## colltype ## _is_end(collection, iter); \
+	     (iter) = lilv_ ## colltype ## _next(collection, iter))
+
+/* LilvPluginClasses */
+
+LILV_API void
+lilv_plugin_classes_free(LilvPluginClasses* collection);
+
+LILV_API unsigned
+lilv_plugin_classes_size(const LilvPluginClasses* collection);
+
+LILV_API LilvIter*
+lilv_plugin_classes_begin(const LilvPluginClasses* collection);
+
+LILV_API const LilvPluginClass*
+lilv_plugin_classes_get(const LilvPluginClasses* collection, LilvIter* i);
+
+LILV_API LilvIter*
+lilv_plugin_classes_next(const LilvPluginClasses* collection, LilvIter* i);
+
+LILV_API bool
+lilv_plugin_classes_is_end(const LilvPluginClasses* collection, LilvIter* i);
+
+/**
+   Get a plugin class from `classes` by URI.
+   Return value is shared (stored in `classes`) and must not be freed or
+   modified by the caller in any way.
+   @return NULL if no plugin class with `uri` is found in `classes`.
+*/
+LILV_API const LilvPluginClass*
+lilv_plugin_classes_get_by_uri(const LilvPluginClasses* classes,
+                               const LilvNode*          uri);
+
+/* ScalePoints */
+
+LILV_API void
+lilv_scale_points_free(LilvScalePoints* collection);
+
+LILV_API unsigned
+lilv_scale_points_size(const LilvScalePoints* collection);
+
+LILV_API LilvIter*
+lilv_scale_points_begin(const LilvScalePoints* collection);
+
+LILV_API const LilvScalePoint*
+lilv_scale_points_get(const LilvScalePoints* collection, LilvIter* i);
+
+LILV_API LilvIter*
+lilv_scale_points_next(const LilvScalePoints* collection, LilvIter* i);
+
+LILV_API bool
+lilv_scale_points_is_end(const LilvScalePoints* collection, LilvIter* i);
+
+/* UIs */
+
+LILV_API void
+lilv_uis_free(LilvUIs* collection);
+
+LILV_API unsigned
+lilv_uis_size(const LilvUIs* collection);
+
+LILV_API LilvIter*
+lilv_uis_begin(const LilvUIs* collection);
+
+LILV_API const LilvUI*
+lilv_uis_get(const LilvUIs* collection, LilvIter* i);
+
+LILV_API LilvIter*
+lilv_uis_next(const LilvUIs* collection, LilvIter* i);
+
+LILV_API bool
+lilv_uis_is_end(const LilvUIs* collection, LilvIter* i);
+
+/**
+   Get a UI from `uis` by URI.
+   Return value is shared (stored in `uis`) and must not be freed or
+   modified by the caller in any way.
+   @return NULL if no UI with `uri` is found in `list`.
+*/
+LILV_API const LilvUI*
+lilv_uis_get_by_uri(const LilvUIs*  uis,
+                    const LilvNode* uri);
+
+/* Nodes */
+
+LILV_API void
+lilv_nodes_free(LilvNodes* collection);
+
+LILV_API unsigned
+lilv_nodes_size(const LilvNodes* collection);
+
+LILV_API LilvIter*
+lilv_nodes_begin(const LilvNodes* collection);
+
+LILV_API const LilvNode*
+lilv_nodes_get(const LilvNodes* collection, LilvIter* i);
+
+LILV_API LilvIter*
+lilv_nodes_next(const LilvNodes* collection, LilvIter* i);
+
+LILV_API bool
+lilv_nodes_is_end(const LilvNodes* collection, LilvIter* i);
+
+LILV_API LilvNode*
+lilv_nodes_get_first(const LilvNodes* collection);
+
+/**
+   Return whether `values` contains `value`.
+*/
+LILV_API bool
+lilv_nodes_contains(const LilvNodes* nodes, const LilvNode* value);
+
+/**
+   Return a new LilvNodes that contains all nodes from both `a` and `b`.
+*/
+LILV_API LilvNodes*
+lilv_nodes_merge(const LilvNodes* a, const LilvNodes* b);
+
+/* Plugins */
+
+LILV_API unsigned
+lilv_plugins_size(const LilvPlugins* collection);
+
+LILV_API LilvIter*
+lilv_plugins_begin(const LilvPlugins* collection);
+
+LILV_API const LilvPlugin*
+lilv_plugins_get(const LilvPlugins* collection, LilvIter* i);
+
+LILV_API LilvIter*
+lilv_plugins_next(const LilvPlugins* collection, LilvIter* i);
+
+LILV_API bool
+lilv_plugins_is_end(const LilvPlugins* collection, LilvIter* i);
+
+/**
+   Get a plugin from `plugins` by URI.
+   Return value is shared (stored in `plugins`) and must not be freed or
+   modified by the caller in any way.
+   @return NULL if no plugin with `uri` is found in `plugins`.
+*/
+LILV_API const LilvPlugin*
+lilv_plugins_get_by_uri(const LilvPlugins* plugins,
+                        const LilvNode*    uri);
+
+/**
+   @}
+   @name World
+   The "world" represents all Lilv state, and is used to discover/load/cache
+   LV2 data (plugins, UIs, and extensions).
+   Normal hosts which just need to load plugins by URI should simply use
+   lilv_world_load_all() to discover/load the system's LV2 resources.
+   @{
+*/
+
+/**
+   Initialize a new, empty world.
+   If initialization fails, NULL is returned.
+*/
+LILV_API LilvWorld*
+lilv_world_new(void);
+
+/**
+   Enable/disable language filtering.
+   Language filtering applies to any functions that return (a) value(s).
+   With filtering enabled, Lilv will automatically return the best value(s)
+   for the current LANG.  With filtering disabled, all matching values will
+   be returned regardless of language tag.  Filtering is enabled by default.
+*/
+#define LILV_OPTION_FILTER_LANG "http://drobilla.net/ns/lilv#filter-lang"
+
+/**
+   Enable/disable dynamic manifest support.
+   Dynamic manifest data will only be loaded if this option is true.
+*/
+#define LILV_OPTION_DYN_MANIFEST "http://drobilla.net/ns/lilv#dyn-manifest"
+
+/**
+   Set application-specific LV2_PATH.  This overrides the LV2_PATH from the
+   environment, so that lilv will only look inside the given path.  This can be
+   used to make self-contained applications.
+*/
+#define LILV_OPTION_LV2_PATH "http://drobilla.net/ns/lilv#lv2-path"
+
+/**
+   Set an option option for `world`.
+
+   Currently recognized options:
+   @ref LILV_OPTION_FILTER_LANG
+   @ref LILV_OPTION_DYN_MANIFEST
+   @ref LILV_OPTION_LV2_PATH
+*/
+LILV_API void
+lilv_world_set_option(LilvWorld*      world,
+                      const char*     uri,
+                      const LilvNode* value);
+
+/**
+   Destroy the world, mwahaha.
+   It is safe to call this function on NULL.
+   Note that destroying `world` will destroy all the objects it contains
+   (e.g. instances of LilvPlugin).  Do not destroy the world until you are
+   finished with all objects that came from it.
+*/
+LILV_API void
+lilv_world_free(LilvWorld* world);
+
+/**
+   Load all installed LV2 bundles on the system.
+   This is the recommended way for hosts to load LV2 data.  It implements the
+   established/standard best practice for discovering all LV2 data on the
+   system.  The environment variable LV2_PATH may be used to control where
+   this function will look for bundles.
+
+   Hosts should use this function rather than explicitly load bundles, except
+   in special circumstances (e.g. development utilities, or hosts that ship
+   with special plugin bundles which are installed to a known location).
+*/
+LILV_API void
+lilv_world_load_all(LilvWorld* world);
+
+/**
+   Load a specific bundle.
+   `bundle_uri` must be a fully qualified URI to the bundle directory,
+   with the trailing slash, eg. file:///usr/lib/lv2/foo.lv2/
+
+   Normal hosts should not need this function (use lilv_world_load_all()).
+
+   Hosts MUST NOT attach any long-term significance to bundle paths
+   (e.g. in save files), since there are no guarantees they will remain
+   unchanged between (or even during) program invocations. Plugins (among
+   other things) MUST be identified by URIs (not paths) in save files.
+*/
+LILV_API void
+lilv_world_load_bundle(LilvWorld*      world,
+                       const LilvNode* bundle_uri);
+
+/**
+   Load all specifications from currently loaded bundles.
+
+   This is for hosts that explicitly load specific bundles, its use is not
+   necessary when using lilv_world_load_all().  This function parses the
+   specifications and adds them to the model.
+*/
+LILV_API void
+lilv_world_load_specifications(LilvWorld* world);
+
+/**
+   Load all plugin classes from currently loaded specifications.
+
+   Must be called after lilv_world_load_specifications().  This is for hosts
+   that explicitly load specific bundles, its use is not necessary when using
+   lilv_world_load_all().
+*/
+LILV_API void
+lilv_world_load_plugin_classes(LilvWorld* world);
+
+/**
+   Unload a specific bundle.
+
+   This unloads statements loaded by lilv_world_load_bundle().  Note that this
+   is not necessarily all information loaded from the bundle.  If any resources
+   have been separately loaded with lilv_world_load_resource(), they must be
+   separately unloaded with lilv_world_unload_resource().
+*/
+LILV_API int
+lilv_world_unload_bundle(LilvWorld* world, const LilvNode* bundle_uri);
+
+/**
+   Load all the data associated with the given `resource`.
+   @param world The world.
+   @param resource Must be a subject (i.e. a URI or a blank node).
+   @return The number of files parsed, or -1 on error
+
+   All accessible data files linked to `resource` with rdfs:seeAlso will be
+   loaded into the world model.
+*/
+LILV_API int
+lilv_world_load_resource(LilvWorld*      world,
+                         const LilvNode* resource);
+
+/**
+   Unload all the data associated with the given `resource`.
+   @param world The world.
+   @param resource Must be a subject (i.e. a URI or a blank node).
+
+   This unloads all data loaded by a previous call to
+   lilv_world_load_resource() with the given `resource`.
+*/
+LILV_API int
+lilv_world_unload_resource(LilvWorld*      world,
+                           const LilvNode* resource);
+
+/**
+   Get the parent of all other plugin classes, lv2:Plugin.
+*/
+LILV_API const LilvPluginClass*
+lilv_world_get_plugin_class(const LilvWorld* world);
+
+/**
+   Return a list of all found plugin classes.
+   Returned list is owned by world and must not be freed by the caller.
+*/
+LILV_API const LilvPluginClasses*
+lilv_world_get_plugin_classes(const LilvWorld* world);
+
+/**
+   Return a list of all found plugins.
+   The returned list contains just enough references to query
+   or instantiate plugins.  The data for a particular plugin will not be
+   loaded into memory until a call to an lilv_plugin_* function results in
+   a query (at which time the data is cached with the LilvPlugin so future
+   queries are very fast).
+
+   The returned list and the plugins it contains are owned by `world`
+   and must not be freed by caller.
+*/
+LILV_API const LilvPlugins*
+lilv_world_get_all_plugins(const LilvWorld* world);
+
+/**
+   Find nodes matching a triple pattern.
+   Either `subject` or `object` may be NULL (i.e. a wildcard), but not both.
+   @return All matches for the wildcard field, or NULL.
+*/
+LILV_API LilvNodes*
+lilv_world_find_nodes(LilvWorld*      world,
+                      const LilvNode* subject,
+                      const LilvNode* predicate,
+                      const LilvNode* object);
+
+/**
+   Find a single node that matches a pattern.
+   Exactly one of `subject`, `predicate`, `object` must be NULL.
+   This function is equivalent to
+   lilv_nodes_get_first(lilv_world_find_nodes(...)) but simplifies the common
+   case of only wanting a single value.
+   @return the first matching node, or NULL if no matches are found.
+*/
+LILV_API LilvNode*
+lilv_world_get(LilvWorld*      world,
+               const LilvNode* subject,
+               const LilvNode* predicate,
+               const LilvNode* object);
+
+/**
+   Return true iff a statement matching a certain pattern exists.
+
+   This is useful for checking if particular statement exists without having to
+   bother with collections and memory management.
+
+   @param world The world.
+   @param subject Subject of statement, or NULL for anything.
+   @param predicate Predicate (key) of statement, or NULL for anything.
+   @param object Object (value) of statement, or NULL for anything.
+*/
+LILV_API bool
+lilv_world_ask(LilvWorld*      world,
+               const LilvNode* subject,
+               const LilvNode* predicate,
+               const LilvNode* object);
+
+/**
+   Get an LV2 symbol for some subject.
+
+   This will return the lv2:symbol property of the subject if it is given
+   explicitly, and otherwise will attempt to derive a symbol from the URI.
+   @return A string node that is a valid LV2 symbol, or NULL on error.
+*/
+LILV_API LilvNode*
+lilv_world_get_symbol(LilvWorld* world, const LilvNode* subject);
+
+/**
+   @}
+   @name Plugin
+   @{
+*/
+
+/**
+   Check if `plugin` is valid.
+   This is not a rigorous validator, but can be used to reject some malformed
+   plugins that could cause bugs (e.g. plugins with missing required fields).
+
+   Note that normal hosts do NOT need to use this - lilv does not
+   load invalid plugins into plugin lists.  This is included for plugin
+   testing utilities, etc.
+   @return true iff `plugin` is valid.
+*/
+LILV_API bool
+lilv_plugin_verify(const LilvPlugin* plugin);
+
+/**
+   Get the URI of `plugin`.
+   Any serialization that refers to plugins should refer to them by this.
+   Hosts SHOULD NOT save any filesystem paths, plugin indexes, etc. in saved
+   files; save only the URI.
+
+   The URI is a globally unique identifier for one specific plugin.  Two
+   plugins with the same URI are compatible in port signature, and should
+   be guaranteed to work in a compatible and consistent way.  If a plugin
+   is upgraded in an incompatible way (eg if it has different ports), it
+   MUST have a different URI than it's predecessor.
+
+   @return A shared URI value which must not be modified or freed.
+*/
+LILV_API const LilvNode*
+lilv_plugin_get_uri(const LilvPlugin* plugin);
+
+/**
+   Get the (resolvable) URI of the plugin's "main" bundle.
+   This returns the URI of the bundle where the plugin itself was found.  Note
+   that the data for a plugin may be spread over many bundles, that is,
+   lilv_plugin_get_data_uris() may return URIs which are not within this
+   bundle.
+
+   Typical hosts should not need to use this function.
+   Note this always returns a fully qualified URI.  If you want a local
+   filesystem path, use lilv_file_uri_parse().
+   @return a shared string which must not be modified or freed.
+*/
+LILV_API const LilvNode*
+lilv_plugin_get_bundle_uri(const LilvPlugin* plugin);
+
+/**
+   Get the (resolvable) URIs of the RDF data files that define a plugin.
+   Typical hosts should not need to use this function.
+   Note this always returns fully qualified URIs.  If you want local
+   filesystem paths, use lilv_file_uri_parse().
+   @return a list of complete URLs eg. "file:///foo/ABundle.lv2/aplug.ttl",
+   which is shared and must not be modified or freed.
+*/
+LILV_API const LilvNodes*
+lilv_plugin_get_data_uris(const LilvPlugin* plugin);
+
+/**
+   Get the (resolvable) URI of the shared library for `plugin`.
+   Note this always returns a fully qualified URI.  If you want a local
+   filesystem path, use lilv_file_uri_parse().
+   @return a shared string which must not be modified or freed.
+*/
+LILV_API const LilvNode*
+lilv_plugin_get_library_uri(const LilvPlugin* plugin);
+
+/**
+   Get the name of `plugin`.
+   This returns the name (doap:name) of the plugin.  The name may be
+   translated according to the current locale, this value MUST NOT be used
+   as a plugin identifier (use the URI for that).
+   Returned value must be freed by the caller.
+*/
+LILV_API LilvNode*
+lilv_plugin_get_name(const LilvPlugin* plugin);
+
+/**
+   Get the class this plugin belongs to (e.g. Filters).
+*/
+LILV_API const LilvPluginClass*
+lilv_plugin_get_class(const LilvPlugin* plugin);
+
+/**
+   Get a value associated with the plugin in a plugin's data files.
+   `predicate` must be either a URI or a QName.
+
+   Returns the ?object of all triples found of the form:
+
+   <code>&lt;plugin-uri&gt; predicate ?object</code>
+
+   May return NULL if the property was not found, or if object(s) is not
+   sensibly represented as a LilvNodes (e.g. blank nodes).
+   Return value must be freed by caller with lilv_nodes_free().
+*/
+LILV_API LilvNodes*
+lilv_plugin_get_value(const LilvPlugin* plugin,
+                      const LilvNode*   predicate);
+
+/**
+   Return whether a feature is supported by a plugin.
+   This will return true if the feature is an optional or required feature
+   of the plugin.
+*/
+LILV_API bool
+lilv_plugin_has_feature(const LilvPlugin* plugin,
+                        const LilvNode*   feature);
+
+/**
+   Get the LV2 Features supported (required or optionally) by a plugin.
+   A feature is "supported" by a plugin if it is required OR optional.
+
+   Since required features have special rules the host must obey, this function
+   probably shouldn't be used by normal hosts.  Using lilv_plugin_get_optional_features()
+   and lilv_plugin_get_required_features() separately is best in most cases.
+
+   Returned value must be freed by caller with lilv_nodes_free().
+*/
+LILV_API LilvNodes*
+lilv_plugin_get_supported_features(const LilvPlugin* plugin);
+
+/**
+   Get the LV2 Features required by a plugin.
+   If a feature is required by a plugin, hosts MUST NOT use the plugin if they do not
+   understand (or are unable to support) that feature.
+
+   All values returned here MUST be passed to the plugin's instantiate method
+   (along with data, if necessary, as defined by the feature specification)
+   or plugin instantiation will fail.
+
+   Return value must be freed by caller with lilv_nodes_free().
+*/
+LILV_API LilvNodes*
+lilv_plugin_get_required_features(const LilvPlugin* plugin);
+
+/**
+   Get the LV2 Features optionally supported by a plugin.
+   Hosts MAY ignore optional plugin features for whatever reasons.  Plugins
+   MUST operate (at least somewhat) if they are instantiated without being
+   passed optional features.
+
+   Return value must be freed by caller with lilv_nodes_free().
+*/
+LILV_API LilvNodes*
+lilv_plugin_get_optional_features(const LilvPlugin* plugin);
+
+/**
+   Return whether or not a plugin provides a specific extension data.
+*/
+LILV_API bool
+lilv_plugin_has_extension_data(const LilvPlugin* plugin,
+                               const LilvNode*   uri);
+
+/**
+   Get a sequence of all extension data provided by a plugin.
+   This can be used to find which URIs lilv_instance_get_extension_data()
+   will return a value for without instantiating the plugin.
+*/
+LILV_API LilvNodes*
+lilv_plugin_get_extension_data(const LilvPlugin* plugin);
+
+/**
+   Get the number of ports on this plugin.
+*/
+LILV_API uint32_t
+lilv_plugin_get_num_ports(const LilvPlugin* plugin);
+
+/**
+   Get the port ranges (minimum, maximum and default values) for all ports.
+   `min_values`, `max_values` and `def_values` must either point to an array
+   of N floats, where N is the value returned by lilv_plugin_get_num_ports()
+   for this plugin, or NULL.  The elements of the array will be set to the
+   the minimum, maximum and default values of the ports on this plugin,
+   with array index corresponding to port index.  If a port doesn't have a
+   minimum, maximum or default value, or the port's type is not float, the
+   corresponding array element will be set to NAN.
+
+   This is a convenience method for the common case of getting the range of
+   all float ports on a plugin, and may be significantly faster than
+   repeated calls to lilv_port_get_range().
+*/
+LILV_API void
+lilv_plugin_get_port_ranges_float(const LilvPlugin* plugin,
+                                  float*            min_values,
+                                  float*            max_values,
+                                  float*            def_values);
+
+/**
+   Get the number of ports on this plugin that are members of some class(es).
+   Note that this is a varargs function so ports fitting any type 'profile'
+   desired can be found quickly.  REMEMBER TO TERMINATE THE PARAMETER LIST
+   OF THIS FUNCTION WITH NULL OR VERY NASTY THINGS WILL HAPPEN.
+*/
+LILV_API uint32_t
+lilv_plugin_get_num_ports_of_class(const LilvPlugin* plugin,
+                                   const LilvNode*   class_1, ...);
+
+/**
+   Variant of lilv_plugin_get_num_ports_of_class() that takes a va_list.
+
+   This function calls va_arg() on `args` but does not call va_end().
+*/
+LILV_API uint32_t
+lilv_plugin_get_num_ports_of_class_va(const LilvPlugin* plugin,
+                                      const LilvNode*   class_1,
+                                      va_list           args);
+
+/**
+   Return whether or not the plugin introduces (and reports) latency.
+   The index of the latency port can be found with
+   lilv_plugin_get_latency_port() ONLY if this function returns true.
+*/
+LILV_API bool
+lilv_plugin_has_latency(const LilvPlugin* plugin);
+
+/**
+   Return the index of the plugin's latency port.
+   It is a fatal error to call this on a plugin without checking if the port
+   exists by first calling lilv_plugin_has_latency().
+
+   Any plugin that introduces unwanted latency that should be compensated for
+   (by hosts with the ability/need) MUST provide this port, which is a control
+   rate output port that reports the latency for each cycle in frames.
+*/
+LILV_API uint32_t
+lilv_plugin_get_latency_port_index(const LilvPlugin* plugin);
+
+/**
+   Get a port on `plugin` by `index`.
+*/
+LILV_API const LilvPort*
+lilv_plugin_get_port_by_index(const LilvPlugin* plugin,
+                              uint32_t          index);
+
+/**
+   Get a port on `plugin` by `symbol`.
+   Note this function is slower than lilv_plugin_get_port_by_index(),
+   especially on plugins with a very large number of ports.
+*/
+LILV_API const LilvPort*
+lilv_plugin_get_port_by_symbol(const LilvPlugin* plugin,
+                               const LilvNode*   symbol);
+
+/**
+   Get a port on `plugin` by its lv2:designation.
+
+   The designation of a port describes the meaning, assignment, allocation or
+   role of the port, e.g. "left channel" or "gain".  If found, the port with
+   matching `port_class` and `designation` is be returned, otherwise NULL is
+   returned.  The `port_class` can be used to distinguish the input and output
+   ports for a particular designation.  If `port_class` is NULL, any port with
+   the given designation will be returned.
+*/
+LILV_API const LilvPort*
+lilv_plugin_get_port_by_designation(const LilvPlugin* plugin,
+                                    const LilvNode*   port_class,
+                                    const LilvNode*   designation);
+
+/**
+   Get the project the plugin is a part of.
+
+   More information about the project can be read via lilv_world_find_nodes(),
+   typically using properties from DOAP (e.g. doap:name).
+*/
+LILV_API LilvNode*
+lilv_plugin_get_project(const LilvPlugin* plugin);
+
+/**
+   Get the full name of the plugin's author.
+   Returns NULL if author name is not present.
+   Returned value must be freed by caller.
+*/
+LILV_API LilvNode*
+lilv_plugin_get_author_name(const LilvPlugin* plugin);
+
+/**
+   Get the email address of the plugin's author.
+   Returns NULL if author email address is not present.
+   Returned value must be freed by caller.
+*/
+LILV_API LilvNode*
+lilv_plugin_get_author_email(const LilvPlugin* plugin);
+
+/**
+   Get the address of the plugin author's home page.
+   Returns NULL if author homepage is not present.
+   Returned value must be freed by caller.
+*/
+LILV_API LilvNode*
+lilv_plugin_get_author_homepage(const LilvPlugin* plugin);
+
+/**
+   Return true iff `plugin` has been replaced by another plugin.
+
+   The plugin will still be usable, but hosts should hide them from their
+   user interfaces to prevent users from using deprecated plugins.
+*/
+LILV_API bool
+lilv_plugin_is_replaced(const LilvPlugin* plugin);
+
+/**
+   Write the Turtle description of `plugin` to `plugin_file`.
+
+   This function is particularly useful for porting plugins in conjunction with
+   an LV2 bridge such as NASPRO.
+*/
+LILV_API void
+lilv_plugin_write_description(LilvWorld*        world,
+                              const LilvPlugin* plugin,
+                              const LilvNode*   base_uri,
+                              FILE*             plugin_file);
+
+/**
+   Write a manifest entry for `plugin` to `manifest_file`.
+
+   This function is intended for use with lilv_plugin_write_description() to
+   write a complete description of a plugin to a bundle.
+*/
+LILV_API void
+lilv_plugin_write_manifest_entry(LilvWorld*        world,
+                                 const LilvPlugin* plugin,
+                                 const LilvNode*   base_uri,
+                                 FILE*             manifest_file,
+                                 const char*       plugin_file_path);
+
+/**
+   Get the resources related to `plugin` with lv2:appliesTo.
+
+   Some plugin-related resources are not linked directly to the plugin with
+   rdfs:seeAlso and thus will not be automatically loaded along with the plugin
+   data (usually for performance reasons).  All such resources of the given @c
+   type related to `plugin` can be accessed with this function.
+
+   If `type` is NULL, all such resources will be returned, regardless of type.
+
+   To actually load the data for each returned resource, use
+   lilv_world_load_resource().
+*/
+LILV_API LilvNodes*
+lilv_plugin_get_related(const LilvPlugin* plugin, const LilvNode* type);
+
+/**
+   @}
+   @name Port
+   @{
+*/
+
+/**
+   Get the RDF node of `port`.
+
+   Ports nodes may be may be URIs or blank nodes.
+
+   @return A shared node which must not be modified or freed.
+*/
+LILV_API const LilvNode*
+lilv_port_get_node(const LilvPlugin* plugin,
+                   const LilvPort*   port);
+
+/**
+   Port analog of lilv_plugin_get_value().
+*/
+LILV_API LilvNodes*
+lilv_port_get_value(const LilvPlugin* plugin,
+                    const LilvPort*   port,
+                    const LilvNode*   predicate);
+
+/**
+   Get a single property value of a port.
+
+   This is equivalent to lilv_nodes_get_first(lilv_port_get_value(...)) but is
+   simpler to use in the common case of only caring about one value.  The
+   caller is responsible for freeing the returned node.
+*/
+LILV_API LilvNode*
+lilv_port_get(const LilvPlugin* plugin,
+              const LilvPort*   port,
+              const LilvNode*   predicate);
+
+/**
+   Return the LV2 port properties of a port.
+*/
+LILV_API LilvNodes*
+lilv_port_get_properties(const LilvPlugin* plugin,
+                         const LilvPort*   port);
+
+/**
+   Return whether a port has a certain property.
+*/
+LILV_API bool
+lilv_port_has_property(const LilvPlugin* plugin,
+                       const LilvPort*   port,
+                       const LilvNode*   property);
+
+/**
+   Return whether a port supports a certain event type.
+
+   More precisely, this returns true iff the port has an atom:supports or an
+   ev:supportsEvent property with `event_type` as the value.
+*/
+LILV_API bool
+lilv_port_supports_event(const LilvPlugin* plugin,
+                         const LilvPort*   port,
+                         const LilvNode*   event_type);
+
+/**
+   Get the index of a port.
+   The index is only valid for the life of the plugin and may change between
+   versions.  For a stable identifier, use the symbol.
+*/
+LILV_API uint32_t
+lilv_port_get_index(const LilvPlugin* plugin,
+                    const LilvPort*   port);
+
+/**
+   Get the symbol of a port.
+   The 'symbol' is a short string, a valid C identifier.
+   Returned value is owned by `port` and must not be freed.
+*/
+LILV_API const LilvNode*
+lilv_port_get_symbol(const LilvPlugin* plugin,
+                     const LilvPort*   port);
+
+/**
+   Get the name of a port.
+   This is guaranteed to return the untranslated name (the doap:name in the
+   data file without a language tag).  Returned value must be freed by
+   the caller.
+*/
+LILV_API LilvNode*
+lilv_port_get_name(const LilvPlugin* plugin,
+                   const LilvPort*   port);
+
+/**
+   Get all the classes of a port.
+   This can be used to determine if a port is an input, output, audio,
+   control, midi, etc, etc, though it's simpler to use lilv_port_is_a().
+   The returned list does not include lv2:Port, which is implied.
+   Returned value is shared and must not be destroyed by caller.
+*/
+LILV_API const LilvNodes*
+lilv_port_get_classes(const LilvPlugin* plugin,
+                      const LilvPort*   port);
+
+/**
+   Determine if a port is of a given class (input, output, audio, etc).
+   For convenience/performance/extensibility reasons, hosts are expected to
+   create a LilvNode for each port class they "care about".  Well-known type
+   URI strings are defined (e.g. LILV_URI_INPUT_PORT) for convenience, but
+   this function is designed so that Lilv is usable with any port types
+   without requiring explicit support in Lilv.
+*/
+LILV_API bool
+lilv_port_is_a(const LilvPlugin* plugin,
+               const LilvPort*   port,
+               const LilvNode*   port_class);
+
+/**
+   Get the default, minimum, and maximum values of a port.
+
+   `def`, `min`, and `max` are outputs, pass pointers to uninitialized
+   LilvNode* variables.  These will be set to point at new values (which must
+   be freed by the caller using lilv_node_free()), or NULL if the value does
+   not exist.
+*/
+LILV_API void
+lilv_port_get_range(const LilvPlugin* plugin,
+                    const LilvPort*   port,
+                    LilvNode**        def,
+                    LilvNode**        min,
+                    LilvNode**        max);
+
+/**
+   Get the scale points (enumeration values) of a port.
+   This returns a collection of 'interesting' named values of a port
+   (e.g. appropriate entries for a UI selector associated with this port).
+   Returned value may be NULL if `port` has no scale points, otherwise it
+   must be freed by caller with lilv_scale_points_free().
+*/
+LILV_API LilvScalePoints*
+lilv_port_get_scale_points(const LilvPlugin* plugin,
+                           const LilvPort*   port);
+
+/**
+   @}
+   @name Plugin State
+   @{
+*/
+
+/**
+   Load a state snapshot from the world RDF model.
+   This function can be used to load the default state of a plugin by passing
+   the plugin URI as the `subject` parameter.
+   @param world The world.
+   @param map URID mapper.
+   @param node The subject of the state description (e.g. a preset URI).
+   @return A new LilvState which must be freed with lilv_state_free(), or NULL.
+*/
+LILV_API LilvState*
+lilv_state_new_from_world(LilvWorld*      world,
+                          LV2_URID_Map*   map,
+                          const LilvNode* node);
+
+/**
+   Load a state snapshot from a file.
+   @param world The world.
+   @param map URID mapper.
+   @param subject The subject of the state description (e.g. a preset URI).
+   @param path The path of the file containing the state description.
+   @return A new LilvState which must be freed with lilv_state_free().
+
+   If `subject` is NULL, it is taken to be the URI of the file (i.e.
+   "<>" in Turtle).
+
+   This function parses the file separately to create the state, it does not
+   parse the file into the world model, i.e. the returned state is the only
+   new memory consumed once this function returns.
+*/
+LILV_API LilvState*
+lilv_state_new_from_file(LilvWorld*      world,
+                         LV2_URID_Map*   map,
+                         const LilvNode* subject,
+                         const char*     path);
+
+/**
+   Load a state snapshot from a string made by lilv_state_to_string().
+*/
+LILV_API LilvState*
+lilv_state_new_from_string(LilvWorld*    world,
+                           LV2_URID_Map* map,
+                           const char*   str);
+
+/**
+   Function to get a port value.
+   @param port_symbol The symbol of the port.
+   @param user_data The user_data passed to lilv_state_new_from_instance().
+   @param size (Output) The size of the returned value.
+   @param type (Output) The URID of the type of the returned value.
+   @return A pointer to the port value.
+
+   This function MUST set `size` and `type` appropriately.
+*/
+typedef const void* (*LilvGetPortValueFunc)(const char* port_symbol,
+                                            void*       user_data,
+                                            uint32_t*   size,
+                                            uint32_t*   type);
+
+/**
+   Create a new state snapshot from a plugin instance.
+
+   @param plugin The plugin this state applies to.
+
+   @param instance An instance of `plugin`.
+
+   @param map The map to use for mapping URIs in state.
+
+   @param scratch_dir Directory of files created by the plugin earlier, or
+   NULL.  This is for hosts that support file creation at any time with state
+   state:makePath.  These files will be copied as necessary to `copy_dir` and
+   not be referred to directly in state (a temporary directory is appropriate).
+
+   @param copy_dir Directory of copies of files in `scratch_dir`, or NULL.
+   This directory will have the same structure as `scratch_dir` but with
+   possibly modified file names to distinguish revisions.  This allows the
+   saved state to contain the exact contents of the scratch file at save time,
+   so that the state is not ruined if the file is later modified (for example,
+   by the plugin continuing to record).  This can be the same as `save_dir` to
+   create a copy in the state bundle, but can also be a separate directory
+   which allows multiple state snapshots to share a single copy if the file has
+   not changed.
+
+   @param link_dir Directory of links to external files, or NULL.  A link will
+   be made in this directory to any external files referred to in plugin state.
+   In turn, links will be created in the save directory to these links (e.g.
+   save_dir/file => link_dir/file => /foo/bar/file).  This allows many state
+   snapshots to share a single link to an external file, so archival (e.g. with
+   tar -h) will not create several copies of the file.  If this is not
+   required, it can be the same as `save_dir`.
+
+   @param save_dir Directory of files created by plugin during save (or NULL).
+   This is typically the bundle directory later passed to lilv_state_save().
+
+   @param get_value Function to get port values (or NULL).  If NULL, the
+   returned state will not represent port values.  This should only be NULL in
+   hosts that save and restore port values via some other mechanism.
+
+   @param user_data User data to pass to `get_value`.
+
+   @param flags Bitwise OR of LV2_State_Flags values.
+
+   @param features Features to pass LV2_State_Interface.save().
+
+   @return A new LilvState which must be freed with lilv_state_free().
+
+   This function may be called simultaneously with any instance function
+   (except discovery functions) unless the threading class of that function
+   explicitly disallows this.
+
+   To support advanced file functionality, there are several directory
+   parameters.  The multiple parameters are necessary to support saving an
+   instance's state many times, or saving states from multiple instances, while
+   avoiding any duplication of data.  For example, a host could pass the same
+   `copy_dir` and `link_dir` for all plugins in a session (for example
+   `session/shared/copy/` `session/shared/link/`), while the `save_dir` would
+   be unique to each plugin instance (for example `session/states/state1.lv2`
+   for one instance and `session/states/state2.lv2` for another instance).
+   Simple hosts that only wish to save a single plugin's state once may simply
+   use the same directory for all of them, or pass NULL to not support files at
+   all.
+
+   If supported (via state:makePath passed to LV2_Descriptor::instantiate()),
+   `scratch_dir` should be the directory where any files created by the plugin
+   (for example during instantiation or while running) are stored.  Any files
+   here that are referred to in the state will be copied to preserve their
+   contents at the time of the save.  Lilv will assume any files within this
+   directory (recursively) are created by the plugin and that all other files
+   are immutable.  Note that this function does not completely save the state,
+   use lilv_state_save() for that.
+
+   See <a href="http://lv2plug.in/ns/ext/state/state.h">state.h</a> from the
+   LV2 State extension for details on the `flags` and `features` parameters.
+*/
+LILV_API LilvState*
+lilv_state_new_from_instance(const LilvPlugin*          plugin,
+                             LilvInstance*              instance,
+                             LV2_URID_Map*              map,
+                             const char*                scratch_dir,
+                             const char*                copy_dir,
+                             const char*                link_dir,
+                             const char*                save_dir,
+                             LilvGetPortValueFunc       get_value,
+                             void*                      user_data,
+                             uint32_t                   flags,
+                             const LV2_Feature *const * features);
+
+/**
+   Free `state`.
+*/
+LILV_API void
+lilv_state_free(LilvState* state);
+
+/**
+   Return true iff `a` is equivalent to `b`.
+*/
+LILV_API bool
+lilv_state_equals(const LilvState* a, const LilvState* b);
+
+/**
+   Return the number of properties in `state`.
+*/
+LILV_API unsigned
+lilv_state_get_num_properties(const LilvState* state);
+
+/**
+   Get the URI of the plugin `state` applies to.
+*/
+LILV_API const LilvNode*
+lilv_state_get_plugin_uri(const LilvState* state);
+
+/**
+   Get the URI of `state`.
+
+   This may return NULL if the state has not been saved and has no URI.
+*/
+LILV_API const LilvNode*
+lilv_state_get_uri(const LilvState* state);
+
+/**
+   Get the label of `state`.
+*/
+LILV_API const char*
+lilv_state_get_label(const LilvState* state);
+
+/**
+   Set the label of `state`.
+*/
+LILV_API void
+lilv_state_set_label(LilvState*  state,
+                     const char* label);
+
+/**
+   Set a metadata property on `state`.
+   @param state The state to set the metadata for.
+   @param key The key to store `value` under (URID).
+   @param value Pointer to the value to be stored.
+   @param size The size of `value` in bytes.
+   @param type The type of `value` (URID).
+   @param flags LV2_State_Flags for `value`.
+   @return 0 on success.
+
+   This is a generic version of lilv_state_set_label(), which sets metadata
+   properties visible to hosts, but not plugins.  This allows storing useful
+   information such as comments or preset banks.
+*/
+LILV_API int
+lilv_state_set_metadata(LilvState*  state,
+                        uint32_t    key,
+                        const void* value,
+                        size_t      size,
+                        uint32_t    type,
+                        uint32_t    flags);
+
+/**
+   Function to set a port value.
+   @param port_symbol The symbol of the port.
+   @param user_data The user_data passed to lilv_state_restore().
+   @param size The size of `value`.
+   @param type The URID of the type of `value`.
+   @param value A pointer to the port value.
+*/
+typedef void (*LilvSetPortValueFunc)(const char* port_symbol,
+                                     void*       user_data,
+                                     const void* value,
+                                     uint32_t    size,
+                                     uint32_t    type);
+
+/**
+   Enumerate the port values in a state snapshot.
+   @param state The state to retrieve port values from.
+   @param set_value A function to receive port values.
+   @param user_data User data to pass to `set_value`.
+
+   This function is a subset of lilv_state_restore() that only fires the
+   `set_value` callback and does not directly affect a plugin instance.  This
+   is useful in hosts that need to retrieve the port values in a state snapshot
+   for special handling.
+*/
+LILV_API void
+lilv_state_emit_port_values(const LilvState*     state,
+                            LilvSetPortValueFunc set_value,
+                            void*                user_data);
+
+/**
+   Restore a plugin instance from a state snapshot.
+   @param state The state to restore, which must apply to the correct plugin.
+   @param instance An instance of the plugin `state` applies to, or NULL.
+   @param set_value A function to set a port value (may be NULL).
+   @param user_data User data to pass to `set_value`.
+   @param flags Bitwise OR of LV2_State_Flags values.
+   @param features Features to pass LV2_State_Interface.restore().
+
+   This will set all the properties of `instance`, if given, to the values
+   stored in `state`.  If `set_value` is provided, it will be called (with the
+   given `user_data`) to restore each port value, otherwise the host must
+   restore the port values itself (using lilv_state_get_port_value()) in order
+   to completely restore `state`.
+
+   If the state has properties and `instance` is given, this function is in
+   the "instantiation" threading class, i.e. it MUST NOT be called
+   simultaneously with any function on the same plugin instance.  If the state
+   has no properties, only port values are set via `set_value`.
+
+   See <a href="http://lv2plug.in/ns/ext/state/state.h">state.h</a> from the
+   LV2 State extension for details on the `flags` and `features` parameters.
+*/
+LILV_API void
+lilv_state_restore(const LilvState*           state,
+                   LilvInstance*              instance,
+                   LilvSetPortValueFunc       set_value,
+                   void*                      user_data,
+                   uint32_t                   flags,
+                   const LV2_Feature *const * features);
+
+/**
+   Save state to a file.
+   @param world The world.
+   @param map URID mapper.
+   @param unmap URID unmapper.
+   @param state State to save.
+   @param uri URI of state, may be NULL.
+   @param dir Path of the bundle directory to save into.
+   @param filename Path of the state file relative to `dir`.
+
+   The format of state on disk is compatible with that defined in the LV2
+   preset extension, i.e. this function may be used to save presets which can
+   be loaded by any host.
+
+   If `uri` is NULL, the preset URI will be a file URI, but the bundle
+   can safely be moved (i.e. the state file will use "<>" as the subject).
+*/
+LILV_API int
+lilv_state_save(LilvWorld*                 world,
+                LV2_URID_Map*              map,
+                LV2_URID_Unmap*            unmap,
+                const LilvState*           state,
+                const char*                uri,
+                const char*                dir,
+                const char*                filename);
+
+/**
+   Save state to a string.  This function does not use the filesystem.
+
+   @param world The world.
+   @param map URID mapper.
+   @param unmap URID unmapper.
+   @param state The state to serialize.
+   @param uri URI for the state description (mandatory).
+   @param base_uri Base URI for serialisation.  Unless you know what you are
+   doing, pass NULL for this, otherwise the state may not be restorable via
+   lilv_state_new_from_string().
+*/
+LILV_API char*
+lilv_state_to_string(LilvWorld*       world,
+                     LV2_URID_Map*    map,
+                     LV2_URID_Unmap*  unmap,
+                     const LilvState* state,
+                     const char*      uri,
+                     const char*      base_uri);
+
+/**
+   Unload a state from the world and delete all associated files.
+   @param world The world.
+   @param state State to remove from the system.
+
+   This function DELETES FILES/DIRECTORIES FROM THE FILESYSTEM!  It is intended
+   for removing user-saved presets, but can delete any state the user has
+   permission to delete, including presets shipped with plugins.
+
+   The rdfs:seeAlso file for the state will be removed.  The entry in the
+   bundle's manifest.ttl is removed, and if this results in an empty manifest,
+   then the manifest file is removed.  If this results in an empty bundle, then
+   the bundle directory is removed as well.
+*/
+LILV_API int
+lilv_state_delete(LilvWorld*       world,
+                  const LilvState* state);
+
+/**
+   @}
+   @name Scale Point
+   @{
+*/
+
+/**
+   Get the label of this scale point (enumeration value)
+   Returned value is owned by `point` and must not be freed.
+*/
+LILV_API const LilvNode*
+lilv_scale_point_get_label(const LilvScalePoint* point);
+
+/**
+   Get the value of this scale point (enumeration value)
+   Returned value is owned by `point` and must not be freed.
+*/
+LILV_API const LilvNode*
+lilv_scale_point_get_value(const LilvScalePoint* point);
+
+/**
+   @}
+   @name Plugin Class
+   @{
+*/
+
+/**
+   Get the URI of this class' superclass.
+   Returned value is owned by `plugin_class` and must not be freed by caller.
+   Returned value may be NULL, if class has no parent.
+*/
+LILV_API const LilvNode*
+lilv_plugin_class_get_parent_uri(const LilvPluginClass* plugin_class);
+
+/**
+   Get the URI of this plugin class.
+   Returned value is owned by `plugin_class` and must not be freed by caller.
+*/
+LILV_API const LilvNode*
+lilv_plugin_class_get_uri(const LilvPluginClass* plugin_class);
+
+/**
+   Get the label of this plugin class, ie "Oscillators".
+   Returned value is owned by `plugin_class` and must not be freed by caller.
+*/
+LILV_API const LilvNode*
+lilv_plugin_class_get_label(const LilvPluginClass* plugin_class);
+
+/**
+   Get the subclasses of this plugin class.
+   Returned value must be freed by caller with lilv_plugin_classes_free().
+*/
+LILV_API LilvPluginClasses*
+lilv_plugin_class_get_children(const LilvPluginClass* plugin_class);
+
+/**
+   @}
+   @name Plugin Instance
+   @{
+*/
+
+/**
+   @cond LILV_DOCUMENT_INSTANCE_IMPL
+*/
+
+/* Instance of a plugin.
+   This is exposed in the ABI to allow inlining of performance critical
+   functions like lilv_instance_run() (simple wrappers of functions in lv2.h).
+   This is for performance reasons, user code should not use this definition
+   in any way (which is why it is not machine documented).
+   Truly private implementation details are hidden via `pimpl`.
+*/
+struct LilvInstanceImpl {
+	const LV2_Descriptor* lv2_descriptor;
+	LV2_Handle            lv2_handle;
+	void*                 pimpl;
+};
+
+/**
+   @endcond
+*/
+
+/**
+   Instantiate a plugin.
+   The returned value is a lightweight handle for an LV2 plugin instance,
+   it does not refer to `plugin`, or any other Lilv state.  The caller must
+   eventually free it with lilv_instance_free().
+   `features` is a NULL-terminated array of features the host supports.
+   NULL may be passed if the host supports no additional features.
+   @return NULL if instantiation failed.
+*/
+LILV_API LilvInstance*
+lilv_plugin_instantiate(const LilvPlugin*        plugin,
+                        double                   sample_rate,
+                        const LV2_Feature*const* features);
+
+/**
+   Free a plugin instance.
+   It is safe to call this function on NULL.
+   `instance` is invalid after this call.
+*/
+LILV_API void
+lilv_instance_free(LilvInstance* instance);
+
+#ifndef LILV_INTERNAL
+
+/**
+   Get the URI of the plugin which `instance` is an instance of.
+   Returned string is shared and must not be modified or deleted.
+*/
+static inline const char*
+lilv_instance_get_uri(const LilvInstance* instance)
+{
+	return instance->lv2_descriptor->URI;
+}
+
+/**
+   Connect a port to a data location.
+   This may be called regardless of whether the plugin is activated,
+   activation and deactivation does not destroy port connections.
+*/
+static inline void
+lilv_instance_connect_port(LilvInstance* instance,
+                           uint32_t      port_index,
+                           void*         data_location)
+{
+	instance->lv2_descriptor->connect_port
+		(instance->lv2_handle, port_index, data_location);
+}
+
+/**
+   Activate a plugin instance.
+   This resets all state information in the plugin, except for port data
+   locations (as set by lilv_instance_connect_port()).  This MUST be called
+   before calling lilv_instance_run().
+*/
+static inline void
+lilv_instance_activate(LilvInstance* instance)
+{
+	if (instance->lv2_descriptor->activate) {
+		instance->lv2_descriptor->activate(instance->lv2_handle);
+	}
+}
+
+/**
+   Run `instance` for `sample_count` frames.
+   If the hint lv2:hardRTCapable is set for this plugin, this function is
+   guaranteed not to block.
+*/
+static inline void
+lilv_instance_run(LilvInstance* instance,
+                  uint32_t      sample_count)
+{
+	instance->lv2_descriptor->run(instance->lv2_handle, sample_count);
+}
+
+/**
+   Deactivate a plugin instance.
+   Note that to run the plugin after this you must activate it, which will
+   reset all state information (except port connections).
+*/
+static inline void
+lilv_instance_deactivate(LilvInstance* instance)
+{
+	if (instance->lv2_descriptor->deactivate) {
+		instance->lv2_descriptor->deactivate(instance->lv2_handle);
+	}
+}
+
+/**
+   Get extension data from the plugin instance.
+   The type and semantics of the data returned is specific to the particular
+   extension, though in all cases it is shared and must not be deleted.
+*/
+static inline const void*
+lilv_instance_get_extension_data(const LilvInstance* instance,
+                                 const char*         uri)
+{
+	if (instance->lv2_descriptor->extension_data) {
+		return instance->lv2_descriptor->extension_data(uri);
+	} else {
+		return NULL;
+	}
+}
+
+/**
+   Get the LV2_Descriptor of the plugin instance.
+   Normally hosts should not need to access the LV2_Descriptor directly,
+   use the lilv_instance_* functions.
+
+   The returned descriptor is shared and must not be deleted.
+*/
+static inline const LV2_Descriptor*
+lilv_instance_get_descriptor(const LilvInstance* instance)
+{
+	return instance->lv2_descriptor;
+}
+
+/**
+   Get the LV2_Handle of the plugin instance.
+   Normally hosts should not need to access the LV2_Handle directly,
+   use the lilv_instance_* functions.
+
+   The returned handle is shared and must not be deleted.
+*/
+static inline LV2_Handle
+lilv_instance_get_handle(const LilvInstance* instance)
+{
+	return instance->lv2_handle;
+}
+
+#endif /* LILV_INTERNAL */
+
+/**
+   @}
+   @name Plugin UI
+   @{
+*/
+
+/**
+   Get all UIs for `plugin`.
+   Returned value must be freed by caller using lilv_uis_free().
+*/
+LILV_API LilvUIs*
+lilv_plugin_get_uis(const LilvPlugin* plugin);
+
+/**
+   Get the URI of a Plugin UI.
+   @param ui The Plugin UI
+   @return a shared value which must not be modified or freed.
+*/
+LILV_API const LilvNode*
+lilv_ui_get_uri(const LilvUI* ui);
+
+/**
+   Get the types (URIs of RDF classes) of a Plugin UI.
+   @param ui The Plugin UI
+   @return a shared value which must not be modified or freed.
+
+   Note that in most cases lilv_ui_is_supported() should be used, which avoids
+   the need to use this function (and type specific logic).
+*/
+LILV_API const LilvNodes*
+lilv_ui_get_classes(const LilvUI* ui);
+
+/**
+   Check whether a plugin UI has a given type.
+   @param ui        The Plugin UI
+   @param class_uri The URI of the LV2 UI type to check this UI against
+*/
+LILV_API bool
+lilv_ui_is_a(const LilvUI* ui, const LilvNode* class_uri);
+
+/**
+   Function to determine whether a UI type is supported.
+
+   This is provided by the user and must return non-zero iff using a UI of type
+   `ui_type_uri` in a container of type `container_type_uri` is supported.
+*/
+typedef unsigned (*LilvUISupportedFunc)(const char* container_type_uri,
+                                        const char* ui_type_uri);
+
+/**
+   Return true iff a Plugin UI is supported as a given widget type.
+   @param ui The Plugin UI
+   @param supported_func User provided supported predicate.
+   @param container_type The widget type to host the UI within.
+   @param ui_type (Output) If non-NULL, set to the native type of the UI
+   which is owned by `ui` and must not be freed by the caller.
+   @return The embedding quality level returned by `supported_func`.
+*/
+LILV_API unsigned
+lilv_ui_is_supported(const LilvUI*       ui,
+                     LilvUISupportedFunc supported_func,
+                     const LilvNode*     container_type,
+                     const LilvNode**    ui_type);
+
+/**
+   Get the URI for a Plugin UI's bundle.
+   @param ui The Plugin UI
+   @return a shared value which must not be modified or freed.
+*/
+LILV_API const LilvNode*
+lilv_ui_get_bundle_uri(const LilvUI* ui);
+
+/**
+   Get the URI for a Plugin UI's shared library.
+   @param ui The Plugin UI
+   @return a shared value which must not be modified or freed.
+*/
+LILV_API const LilvNode*
+lilv_ui_get_binary_uri(const LilvUI* ui);
+
+/**
+   @}
+   @}
+*/
+
+#ifdef __cplusplus
+#    if defined(__clang__)
+#        pragma clang diagnostic pop
+#    endif
+} /* extern "C" */
+#endif
+
+#endif /* LILV_LILV_H */