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-rw-r--r--ext/persist.lv2/persist.h298
-rw-r--r--ext/persist.lv2/persist.ttl4
2 files changed, 156 insertions, 146 deletions
diff --git a/ext/persist.lv2/persist.h b/ext/persist.lv2/persist.h
index 2ac4880..0a8f4f0 100644
--- a/ext/persist.lv2/persist.h
+++ b/ext/persist.lv2/persist.h
@@ -1,24 +1,26 @@
-/* lv2_persist.h - C header file for the LV2 Persist extension.
- * Copyright (C) 2010 Leonard Ritter <paniq@paniq.org>
- *
- * This header is free software; you can redistribute it and/or modify it
- * under the terms of the GNU Lesser General Public License as published
- * by the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This header is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
- * License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public License
- * along with this header; if not, write to the Free Software Foundation,
- * Inc., 59 Temple Place, Suite 330, Boston, MA 01222-1307 USA
- */
+/*
+ Copyright (C) 2010-2011 David Robillard <http://drobilla.net>
+ Copyright (C) 2010 Leonard Ritter <paniq@paniq.org>
+
+ This header is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published
+ by the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This header is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+ License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with this header; if not, write to the Free Software Foundation,
+ Inc., 59 Temple Place, Suite 330, Boston, MA 01222-1307 USA
+*/
-/** @file
- * C header for the LV2 Persist extension <http://lv2plug.in/ns/ext/persist>.
- */
+/**
+ @file
+ C API for the LV2 Persist extension <http://lv2plug.in/ns/ext/persist>.
+*/
#ifndef LV2_PERSIST_H
#define LV2_PERSIST_H
@@ -29,32 +31,34 @@ extern "C" {
#define LV2_PERSIST_URI "http://lv2plug.in/ns/ext/persist"
-/** A host-provided function to store a value under a given key.
- * @param callback_data Must be the callback_data passed to LV2_Persist.save().
- * @param key The URI key (predicate) under which the value is to be stored.
- * @param value Pointer to the value (object) to be stored.
- * @param size The size of the data at @a value in bytes.
- * @param type The type of @a value, as a URI mapped to an integer.
- *
- * The host passes a callback of this type to LV2_Persist.save(). This
- * callback is called repeatedly by the plugin within LV2_Persist.save() to
- * store all the key/value records that describe its current state.
- *
- * Unless @a type is 0, @a value is guaranteed to be POD (i.e. a region
- * of memory that does not contain pointers and can safely be copied
- * and persisted indefinitely with a simple memcpy). If @a type is 0,
- * then @a value is a reference, as defined by the LV2 Atom extension
- * <http://lv2plug.in/ns/ext/atom/>. Hosts are not required to support
- * references: a plugin MUST NOT expect a host to persist references unless
- * the host supports the feature <http://lv2plug.in/ns/ext/atom#blobSupport>.
- * Plugins SHOULD express their state entirely with POD values.
- *
- * Note that @a size MUST be > 0, and @a value MUST point to a valid region of
- * memory @a size bytes long (this is required to make restore unambiguous).
- *
- * The plugin MUST NOT attempt to use this function outside of the
- * LV2_Persist.restore() context.
- */
+/**
+ A host-provided function to store a value under a given key.
+ @param callback_data Must be the callback_data passed to LV2_Persist.save().
+ @param key The URI key (predicate) under which the value is to be stored.
+ @param value Pointer to the value (object) to be stored.
+ @param size The size of the data at @a value in bytes.
+ @param type The type of @a value, as a URI mapped to an integer.
+
+ The host passes a callback of this type to LV2_Persist.save().
+ This callback is called repeatedly by the plugin within
+ LV2_Persist.save() to store all the key/value records that describe
+ its current state.
+
+ Unless @a type is 0, @a value is guaranteed to be POD (i.e. a region
+ of memory that does not contain pointers and can safely be copied
+ and persisted indefinitely with a simple memcpy). If @a type is 0,
+ then @a value is a reference, as defined by the LV2 Atom extension
+ <http://lv2plug.in/ns/ext/atom/>. Hosts are not required to support
+ references: a plugin MUST NOT expect a host to persist references unless
+ the host supports the feature <http://lv2plug.in/ns/ext/atom#blobSupport>.
+ Plugins SHOULD express their state entirely with POD values.
+
+ Note that @a size MUST be > 0, and @a value MUST point to a valid region of
+ memory @a size bytes long (this is required to make restore unambiguous).
+
+ The plugin MUST NOT attempt to use this function outside of the
+ LV2_Persist.restore() context.
+*/
typedef void (*LV2_Persist_Store_Function)(
void* callback_data,
const char* key,
@@ -62,116 +66,122 @@ typedef void (*LV2_Persist_Store_Function)(
size_t size,
uint32_t type);
-/** A host-provided function to retrieve a value under a given key.
- * @param callback_data Must be the callback_data passed to LV2_Persist.restore().
- * @param key The URI key (predicate) under which a value has been stored.
- * @param size (Output) If non-NULL, set to the size of the restored value.
- * @param type (Output) If non-NULL, set to the type of the restored value.
- * @return A pointer to the restored value (object), or NULL if no value
- * has been stored under @a key.
- *
- * A callback of this type is passed by the host to LV2_Persist.restore(). This
- * callback is called repeatedly by the plugin within LV2_Persist.restore() to
- * retrieve the values of any keys it requires to restore its state.
- *
- * The returned value MUST remain valid until LV2_Persist.restore() returns.
- *
- * The plugin MUST NOT attempt to use this function, or any value returned from
- * it, outside of the LV2_Persist.restore() context. Returned values MAY be
- * copied for later use if necessary.
- */
+/**
+ A host-provided function to retrieve a value under a given key.
+ @param callback_data Must be the callback_data passed to LV2_Persist.restore().
+ @param key The URI key (predicate) under which a value has been stored.
+ @param size (Output) If non-NULL, set to the size of the restored value.
+ @param type (Output) If non-NULL, set to the type of the restored value.
+ @return A pointer to the restored value (object), or NULL if no value
+ has been stored under @a key.
+
+ A callback of this type is passed by the host to LV2_Persist.restore(). This
+ callback is called repeatedly by the plugin within LV2_Persist.restore() to
+ retrieve the values of any keys it requires to restore its state.
+
+ The returned value MUST remain valid until LV2_Persist.restore() returns.
+
+ The plugin MUST NOT attempt to use this function, or any value returned from
+ it, outside of the LV2_Persist.restore() context. Returned values MAY be
+ copied for later use if necessary.
+*/
typedef const void* (*LV2_Persist_Retrieve_Function)(
void* callback_data,
const char* key,
size_t* size,
uint32_t* type);
-/** When the plugin's extension_data is called with argument LV2_PERSIST_URI,
- * the plugin MUST return an LV2_Persist structure, which remains valid for
- * the lifetime of the plugin.
- *
- * The host can use the contained function pointers to save and restore the
- * state of a plugin instance at any time (provided the threading restrictions
- * for the given function are met).
- *
- * The typical use case is to save the plugin's state when a project is
- * saved, and to restore the state when a project has been loaded. Other
- * uses are possible (e.g. cloning plugin instances or taking a snapshot
- * of plugin state).
- *
- * Stored data is only guaranteed to be compatible between instances of plugins
- * with the same URI (i.e. if a change to a plugin would cause a fatal error
- * when restoring state saved by a previous version of that plugin, the plugin
- * URI must change just as it must when a plugin's ports change). Plugin
- * authors should consider this possibility, and always store sensible data
- * with meaningful types to avoid such compatibility issues in the future.
- */
+/**
+ Persist Extension Data.
+
+ When the plugin's extension_data is called with argument LV2_PERSIST_URI,
+ the plugin MUST return an LV2_Persist structure, which remains valid for
+ the lifetime of the plugin.
+
+ The host can use the contained function pointers to save and restore the
+ state of a plugin instance at any time (provided the threading restrictions
+ for the given function are met).
+
+ The typical use case is to save the plugin's state when a project is
+ saved, and to restore the state when a project has been loaded. Other
+ uses are possible (e.g. cloning plugin instances or taking a snapshot
+ of plugin state).
+
+ Stored data is only guaranteed to be compatible between instances of plugins
+ with the same URI (i.e. if a change to a plugin would cause a fatal error
+ when restoring state saved by a previous version of that plugin, the plugin
+ URI must change just as it must when a plugin's ports change). Plugin
+ authors should consider this possibility, and always store sensible data
+ with meaningful types to avoid such compatibility issues in the future.
+*/
typedef struct _LV2_Persist {
- /** Save plugin state using a host-provided @a store callback.
- *
- * @param instance The instance handle of the plugin.
- * @param store The host-provided store callback.
- * @param callback_data An opaque pointer to host data, e.g. the map or
- * file where the values are to be stored. If @a store is called,
- * this MUST be passed as its callback_data parameter.
- *
- * The plugin is expected to store everything necessary to completely
- * restore its state later (possibly much later, in a different
- * process, on a completely different machine, etc.)
- *
- * The @a callback_data pointer and @a store function MUST NOT be
- * used beyond the scope of save().
- *
- * This function has its own special threading class: it may not be
- * called concurrently with any "Instantiation" function, but it
- * may be called concurrently with functions in any other class,
- * unless the definition of that class prohibits it (e.g. it may
- * not be called concurrently with a "Discovery" function, but it
- * may be called concurrently with an "Audio" function. The plugin
- * is responsible for any locking or lock-free techniques necessary
- * to make this possible.
- *
- * Note that in the simple case where state is only modified by
- * restore(), there are no synchronization issues since save() is
- * never called concurrently with restore() (though run() may read
- * it during a save).
- *
- * Plugins that dynamically modify state while running, however,
- * must take care to do so in such a way that a concurrent call to
- * save() will save a consistent representation of plugin state for a
- * single instant in time. The simplest way to do this is to modify a
- * copy of the state map and atomically swap a pointer to the entire
- * map once the changes are complete (for very large state maps,
- * a purely functional map data structure may be more appropriate
- * since a complete copy is not necessary).
- */
+ /**
+ Save plugin state using a host-provided @a store callback.
+
+ @param instance The instance handle of the plugin.
+ @param store The host-provided store callback.
+ @param callback_data An opaque pointer to host data, e.g. the map or
+ file where the values are to be stored. If @a store is called,
+ this MUST be passed as its callback_data parameter.
+
+ The plugin is expected to store everything necessary to completely
+ restore its state later (possibly much later, in a different
+ process, on a completely different machine, etc.)
+
+ The @a callback_data pointer and @a store function MUST NOT be
+ used beyond the scope of save().
+
+ This function has its own special threading class: it may not be
+ called concurrently with any "Instantiation" function, but it
+ may be called concurrently with functions in any other class,
+ unless the definition of that class prohibits it (e.g. it may
+ not be called concurrently with a "Discovery" function, but it
+ may be called concurrently with an "Audio" function. The plugin
+ is responsible for any locking or lock-free techniques necessary
+ to make this possible.
+
+ Note that in the simple case where state is only modified by
+ restore(), there are no synchronization issues since save() is
+ never called concurrently with restore() (though run() may read
+ it during a save).
+
+ Plugins that dynamically modify state while running, however,
+ must take care to do so in such a way that a concurrent call to
+ save() will save a consistent representation of plugin state for a
+ single instant in time. The simplest way to do this is to modify a
+ copy of the state map and atomically swap a pointer to the entire
+ map once the changes are complete (for very large state maps,
+ a purely functional map data structure may be more appropriate
+ since a complete copy is not necessary).
+ */
void (*save)(LV2_Handle instance,
LV2_Persist_Store_Function store,
void* callback_data);
- /** Restore plugin state using a host-provided @a retrieve callback.
- *
- * @param instance The instance handle of the plugin.
- * @param retrieve The host-provided retrieve callback.
- * @param callback_data An opaque pointer to host data, e.g. the map or
- * file from which the values are to be restored. If @a retrieve is
- * called, this MUST be passed as its callback_data parameter.
- *
- * The plugin MAY assume a restored value was set by a previous call to
- * LV2_Persist.save() by a plugin with the same URI.
- *
- * The plugin MUST gracefully fall back to a default value when a
- * value can not be retrieved. This allows the host to reset the
- * plugin state with an empty map.
- *
- * The @a callback_data pointer and @a store function MUST NOT be used
- * beyond the scope of restore().
- *
- * This function is in the "Instantiation" threading class as defined
- * by LV2. This means it MUST NOT be called concurrently with any other
- * function on the same plugin instance.
- */
+ /**
+ Restore plugin state using a host-provided @a retrieve callback.
+
+ @param instance The instance handle of the plugin.
+ @param retrieve The host-provided retrieve callback.
+ @param callback_data An opaque pointer to host data, e.g. the map or
+ file from which the values are to be restored. If @a retrieve is
+ called, this MUST be passed as its callback_data parameter.
+
+ The plugin MAY assume a restored value was set by a previous call to
+ LV2_Persist.save() by a plugin with the same URI.
+
+ The plugin MUST gracefully fall back to a default value when a
+ value can not be retrieved. This allows the host to reset the
+ plugin state with an empty map.
+
+ The @a callback_data pointer and @a store function MUST NOT be used
+ beyond the scope of restore().
+
+ This function is in the "Instantiation" threading class as defined
+ by LV2. This means it MUST NOT be called concurrently with any other
+ function on the same plugin instance.
+ */
void (*restore)(LV2_Handle instance,
LV2_Persist_Retrieve_Function retrieve,
void* callback_data);
diff --git a/ext/persist.lv2/persist.ttl b/ext/persist.lv2/persist.ttl
index 64e217e..aa6a92c 100644
--- a/ext/persist.lv2/persist.ttl
+++ b/ext/persist.lv2/persist.ttl
@@ -29,7 +29,7 @@
@prefix xsd: <http://www.w3.org/2001/XMLSchema> .
<http://lv2plug.in/ns/ext/persist>
- a lv2:Specification ;
+ a lv2:Specification ;
doap:name "LV2 Persist" ;
doap:developer [
a foaf:Person ;
@@ -42,7 +42,7 @@
foaf:homepage <http://drobilla.net/> ;
rdfs:seeAlso <http://drobilla.net/drobilla.rdf>
] ;
- lv2:documentation """
+ lv2:documentation """
<p>This extension provides a mechanism for plugins to save and restore state
across instances, allowing hosts to save configuration/state/data with a
project or fully clone (i.e. make a deep copy of) a plugin instance.</p>