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Diffstat (limited to 'lv2/lv2_state.h')
| -rw-r--r-- | lv2/lv2_state.h | 354 |
1 files changed, 0 insertions, 354 deletions
diff --git a/lv2/lv2_state.h b/lv2/lv2_state.h deleted file mode 100644 index 3d39012..0000000 --- a/lv2/lv2_state.h +++ /dev/null @@ -1,354 +0,0 @@ -/* - Copyright 2010-2011 David Robillard <http://drobilla.net> - Copyright 2010 Leonard Ritter <paniq@paniq.org> - - Permission to use, copy, modify, and/or distribute this software for any - purpose with or without fee is hereby granted, provided that the above - copyright notice and this permission notice appear in all copies. - - THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES - WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF - MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR - ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES - WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN - ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF - OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. -*/ - -/** - @file - C API for the LV2 State extension <http://lv2plug.in/ns/ext/state>. -*/ - -#ifndef LV2_STATE_H -#define LV2_STATE_H - -#include <stdbool.h> -#include <stddef.h> -#include <stdint.h> - -#include "lv2/lv2plug.in/ns/lv2core/lv2.h" - -#ifdef __cplusplus -extern "C" { -#endif - -#define LV2_STATE_URI "http://lv2plug.in/ns/ext/state" - -#define LV2_STATE_INTERFACE_URI LV2_STATE_URI "#Interface" -#define LV2_STATE_PATH_URI LV2_STATE_URI "#Path" -#define LV2_STATE_MAP_PATH_URI LV2_STATE_URI "#pathMap" -#define LV2_STATE_MAKE_PATH_URI LV2_STATE_URI "#newPath" - -typedef void* LV2_State_Handle; -typedef void* LV2_State_Map_Path_Handle; -typedef void* LV2_State_Make_Path_Handle; - -/** - Flags describing value characteristics. - - These flags are used along with the value's type URI to determine how to - (de-)serialise the value data, or whether it is even possible to do so. -*/ -typedef enum { - - /** - Plain Old Data. - - Values with this flag contain no references to non-stateent or - non-global resources (e.g. pointers, handles, local paths, etc.). It is - safe to copy POD values with a simple memcpy and store them for use at - any time in the future on a machine with a compatible architecture - (e.g. the same endianness and alignment). - - Implementations MUST NOT attempt to copy or serialise a non-POD value if - they do not understand its type (and thus know how to correctly do so). - */ - LV2_STATE_IS_POD = 1, - - /** - Portable (architecture independent) data. - - Values with this flag are in a format that is usable on any - architecture, i.e. if the value is saved on one machine it can safely be - restored on another machine regardless of endianness, alignment, etc. - */ - LV2_STATE_IS_PORTABLE = 1 << 1, - - /** - Native data. - - This flag is used by the host to indicate that the saved data is only - going to be used locally in the currently running process (e.g. for - instance duplication or snapshots), so the plugin should use the most - efficient representation possible and not worry about serialisation - and portability. - */ - LV2_STATE_IS_NATIVE = 1 << 2 - -} LV2_State_Flags; - -/** - A host-provided function to store a property. - @param handle Must be the handle passed to LV2_State_Interface.save(). - @param key The key (predicate) to store @c value under (URI mapped integer). - @param value Pointer to the value (object) to be stored. - @param size The size of the data at @c value in bytes. - @param type The type of @c value (URI). - @param flags LV2_State_Flags for @c value. - @return 0 on success, otherwise a non-zero error code. - - The host passes a callback of this type to LV2_State_Interface.save(). This callback - is called repeatedly by the plugin within LV2_State_Interface.save() to store all - the statements that describe its current state. - - The host MAY fail to store a property if the type is not understood and is - not LV2_STATE_IS_POD and/or LV2_STATE_IS_PORTABLE. Implementations are - encouraged to use POD and portable values (e.g. string literals) wherever - possible, and use common types (e.g. types from - http://lv2plug.in/ns/ext/atom) regardless, since hosts are likely to already - contain the necessary implementation. - - Note that @c size MUST be > 0, and @c value MUST point to a valid region of - memory @c size bytes long (this is required to make restore unambiguous). - - The plugin MUST NOT attempt to use this function outside of the - LV2_State_Interface.restore() context. -*/ -typedef int (*LV2_State_Store_Function)(LV2_State_Handle handle, - uint32_t key, - const void* value, - size_t size, - uint32_t type, - uint32_t flags); - -/** - A host-provided function to retrieve a property. - @param handle Must be the handle passed to - LV2_State_Interface.restore(). - @param key The key (predicate) of the property to retrieve (URI). - @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. - @param flags (Output) If non-NULL, set to the LV2_State_Flags for - the returned value. - @return A pointer to the restored value (object), or NULL if no value - has been stored under @c key. - - A callback of this type is passed by the host to - LV2_State_Interface.restore(). This callback is called repeatedly by the - plugin within LV2_State_Interface.restore() to retrieve any properties it - requires to restore its state. - - The returned value MUST remain valid until LV2_State_Interface.restore() - returns. - - The plugin MUST NOT attempt to use this function, or any value returned from - it, outside of the LV2_State_Interface.restore() context. Returned values - MAY be copied for later use if necessary, assuming the plugin knows how to - do so correctly (e.g. the value is POD, or the plugin understands the type). -*/ -typedef const void* (*LV2_State_Retrieve_Function)(LV2_State_Handle handle, - uint32_t key, - size_t* size, - uint32_t* type, - uint32_t* flags); - -/** - State Extension Data. - - When the plugin's extension_data is called with argument LV2_STATE_URI, - the plugin MUST return an LV2_State 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 ports change incompatibly). 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_State_Interface { - - /** - Save plugin state using a host-provided @c store callback. - - @param instance The instance handle of the plugin. - @param store The host-provided store callback. - @param handle An opaque pointer to host data, e.g. the map or - file where the values are to be stored. If @c store is called, this MUST - be passed as its handle parameter. - @param flags Flags describing desires properties of this save. The - plugin SHOULD use these values to determine the most appropriate and/or - efficient serialisation, but is not required to do so. - @param features Extensible parameter for passing any additional - features to be used for this save. - - 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 @c handle pointer and @c 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. - */ - void (*save)(LV2_Handle instance, - LV2_State_Store_Function store, - LV2_State_Handle handle, - uint32_t flags, - const LV2_Feature *const * features); - - - /** - Restore plugin state using a host-provided @c retrieve callback. - - @param instance The instance handle of the plugin. - @param retrieve The host-provided retrieve callback. - @param handle An opaque pointer to host data, e.g. the map or - file from which the values are to be restored. If @c retrieve is - called, this MUST be passed as its handle parameter. - @param flags Currently unused. - @param features Extensible parameter for passing any additional - features to be used for this restore. - - The plugin MAY assume a restored value was set by a previous call to - LV2_State_Interface.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 @c handle pointer and @c 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_State_Retrieve_Function retrieve, - LV2_State_Handle handle, - uint32_t flags, - const LV2_Feature *const * features); - -} LV2_State_Interface; - -/** - Feature data for state:pathMap (LV2_STATE_MAP_PATH_URI). -*/ -typedef struct { - - /** - Opaque host data. - */ - LV2_State_Map_Path_Handle handle; - - /** - Map an absolute path to an abstract path for use in plugin state. - @param handle MUST be the @a handle member of this struct. - @param absolute_path The absolute path of a file. - @return An abstract path suitable for use in plugin state. - - The plugin MUST use this function to map any paths that will be stored - in files in plugin state. The returned value is an abstract path which - MAY not be an actual file system path; @ref absolute_path MUST be used - to map it to an actual path in order to use the file. - - Hosts MAY map paths in any way (e.g. by creating symbolic links within - the plugin's state directory or storing a list of referenced files - elsewhere). Plugins MUST NOT make any assumptions about abstract paths - except that they can be mapped back to an absolute path using @ref - absolute_path. - - This function may only be called within the context of - LV2_State_Interface.save() or LV2_State_Interface.restore(). The caller - is responsible for freeing the returned value. - */ - char* (*abstract_path)(LV2_State_Map_Path_Handle handle, - const char* absolute_path); - - /** - Map an abstract path from plugin state to an absolute path. - @param handle MUST be the @a handle member of this struct. - @param abstract_path An abstract path (e.g. a path from plugin state). - @return An absolute file system path. - - Since abstract paths are not necessarily actual file paths (or at least - not necessarily absolute paths), this function MUST be used in order to - actually open or otherwise use the file referred to by an abstract path. - - This function may only be called within the context of - LV2_State_Interface.save() or LV2_State_Interface.restore(). The caller - is responsible for freeing the returned value. - */ - char* (*absolute_path)(LV2_State_Map_Path_Handle handle, - const char* abstract_path); - -} LV2_State_Map_Path; - -/** - Feature data for state:makePath (@ref LV2_STATE_MAKE_PATH_URI). -*/ -typedef struct { - - /** - Opaque host data. - */ - LV2_State_Make_Path_Handle handle; - - /** - Return a path the plugin may use to create a new file. - @param handle MUST be the @a handle member of this struct. - @param path The path of the new file relative to a namespace unique - to this plugin instance. - @return The absolute path to use for the new file. - - This function can be used by plugins to create files and directories, - either at state saving time (if this feature is passed to - LV2_State_Interface.save()) or any time (if this feature is passed to - LV2_Descriptor.instantiate()). - - The host must do whatever is necessary for the plugin to be able to - create a file at the returned path (e.g. using fopen), including - creating any leading directories. - - If this function is passed to LV2_Descriptor.instantiate(), it may be - called from any non-realtime context. If it is passed to - LV2_State_Interface.save(), it may only be called within the dynamic - scope of that function call. - - The caller is responsible for freeing the returned value with free(). - */ - char* (*path)(LV2_State_Make_Path_Handle handle, - const char* path); - -} LV2_State_Make_Path; - -#ifdef __cplusplus -} /* extern "C" */ -#endif - -#endif /* LV2_STATE_H */ |