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-rw-r--r--ext/persist.lv2/persist.h52
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.