diff options
Diffstat (limited to 'ext/persist.lv2/persist.h')
| -rw-r--r-- | ext/persist.lv2/persist.h | 52 |
1 files changed, 26 insertions, 26 deletions
diff --git a/ext/persist.lv2/persist.h b/ext/persist.lv2/persist.h index 36600bf..b9ac8e5 100644 --- a/ext/persist.lv2/persist.h +++ b/ext/persist.lv2/persist.h @@ -1,17 +1,17 @@ /* 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 @@ -38,12 +38,12 @@ extern "C" { @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, @@ -52,10 +52,10 @@ extern "C" { 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. */ @@ -74,13 +74,13 @@ typedef void (*LV2_Persist_Store_Function)( @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. @@ -97,16 +97,16 @@ typedef const void* (*LV2_Persist_Retrieve_Function)( 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 @@ -115,23 +115,23 @@ typedef const void* (*LV2_Persist_Retrieve_Function)( 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, @@ -140,12 +140,12 @@ typedef struct _LV2_Persist { 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 @@ -161,23 +161,23 @@ typedef struct _LV2_Persist { /** 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 + 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. |