diff options
Diffstat (limited to 'lv2/state')
| -rw-r--r-- | lv2/state/state.h | 441 |
1 files changed, 220 insertions, 221 deletions
diff --git a/lv2/state/state.h b/lv2/state/state.h index 0de3ee4..55db43b 100644 --- a/lv2/state/state.h +++ b/lv2/state/state.h @@ -55,10 +55,13 @@ extern "C" { #endif -typedef void* LV2_State_Handle; ///< Opaque handle for state save/restore -typedef void* LV2_State_Free_Path_Handle; ///< Opaque handle for state:freePath feature -typedef void* LV2_State_Map_Path_Handle; ///< Opaque handle for state:mapPath feature -typedef void* LV2_State_Make_Path_Handle; ///< Opaque handle for state:makePath feature +typedef void* LV2_State_Handle; ///< Opaque handle for state save/restore +typedef void* + LV2_State_Free_Path_Handle; ///< Opaque handle for state:freePath feature +typedef void* + LV2_State_Map_Path_Handle; ///< Opaque handle for state:mapPath feature +typedef void* + LV2_State_Make_Path_Handle; ///< Opaque handle for state:makePath feature /** Flags describing value characteristics. @@ -67,52 +70,52 @@ typedef void* LV2_State_Make_Path_Handle; ///< Opaque handle for state:makePath (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 pointers or references to other areas - of memory. It is safe to copy POD values with a simple memcpy and store - them for the duration of the process. A POD value is not necessarily - safe to trasmit between processes or machines (for example, filenames - are POD), see LV2_STATE_IS_PORTABLE for details. - - 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. A portable value saved on one machine can be restored on - another machine regardless of architecture. The format of portable - values MUST NOT depend on architecture-specific properties like - endianness or alignment. Portable values MUST NOT contain filenames. - */ - 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 (for things - like 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 + /** + Plain Old Data. + + Values with this flag contain no pointers or references to other areas + of memory. It is safe to copy POD values with a simple memcpy and store + them for the duration of the process. A POD value is not necessarily + safe to trasmit between processes or machines (for example, filenames + are POD), see LV2_STATE_IS_PORTABLE for details. + + 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. A portable value saved on one machine can be restored on + another machine regardless of architecture. The format of portable + values MUST NOT depend on architecture-specific properties like + endianness or alignment. Portable values MUST NOT contain filenames. + */ + 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 (for things + like 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 status code for state functions. */ typedef enum { - LV2_STATE_SUCCESS = 0, /**< Completed successfully. */ - LV2_STATE_ERR_UNKNOWN = 1, /**< Unknown error. */ - LV2_STATE_ERR_BAD_TYPE = 2, /**< Failed due to unsupported type. */ - LV2_STATE_ERR_BAD_FLAGS = 3, /**< Failed due to unsupported flags. */ - LV2_STATE_ERR_NO_FEATURE = 4, /**< Failed due to missing features. */ - LV2_STATE_ERR_NO_PROPERTY = 5, /**< Failed due to missing property. */ - LV2_STATE_ERR_NO_SPACE = 6 /**< Failed due to insufficient space. */ + LV2_STATE_SUCCESS = 0, /**< Completed successfully. */ + LV2_STATE_ERR_UNKNOWN = 1, /**< Unknown error. */ + LV2_STATE_ERR_BAD_TYPE = 2, /**< Failed due to unsupported type. */ + LV2_STATE_ERR_BAD_FLAGS = 3, /**< Failed due to unsupported flags. */ + LV2_STATE_ERR_NO_FEATURE = 4, /**< Failed due to missing features. */ + LV2_STATE_ERR_NO_PROPERTY = 5, /**< Failed due to missing property. */ + LV2_STATE_ERR_NO_SPACE = 6 /**< Failed due to insufficient space. */ } LV2_State_Status; /** @@ -148,13 +151,12 @@ typedef enum { The plugin MUST NOT attempt to use this function outside of the LV2_State_Interface.restore() context. */ -typedef LV2_State_Status (*LV2_State_Store_Function)( - LV2_State_Handle handle, - uint32_t key, - const void* value, - size_t size, - uint32_t type, - uint32_t flags); +typedef LV2_State_Status (*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. @@ -174,12 +176,11 @@ typedef LV2_State_Status (*LV2_State_Store_Function)( returns. The plugin MUST NOT attempt to use this function, or any value returned from it, outside of the LV2_State_Interface.restore() context. */ -typedef const void* (*LV2_State_Retrieve_Function)( - LV2_State_Handle handle, - uint32_t key, - size_t* size, - uint32_t* type, - uint32_t* flags); +typedef const void* (*LV2_State_Retrieve_Function)(LV2_State_Handle handle, + uint32_t key, + size_t* size, + uint32_t* type, + uint32_t* flags); /** LV2 Plugin State Interface. @@ -200,186 +201,184 @@ typedef const void* (*LV2_State_Retrieve_Function)( with meaningful types to avoid such problems in the future. */ typedef struct { - /** - Save plugin state using a host-provided `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 which MUST be passed as the - handle parameter to `store` if it is called. - @param flags Flags describing desired properties of this save. These - flags may be used to determine the most appropriate values to store. - @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. Plugins SHOULD store simple POD data whenever - possible, and consider the possibility of state being restored much - later on a different machine. - - The `handle` pointer and `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 (for example, 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. - */ - LV2_State_Status (*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 `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 which MUST be passed as the - handle parameter to `retrieve` if it is called. - @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 `handle` pointer and `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. - */ - LV2_State_Status (*restore)(LV2_Handle instance, - LV2_State_Retrieve_Function retrieve, - LV2_State_Handle handle, - uint32_t flags, - const LV2_Feature *const * features); + /** + Save plugin state using a host-provided `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 which MUST be passed as the + handle parameter to `store` if it is called. + @param flags Flags describing desired properties of this save. These + flags may be used to determine the most appropriate values to store. + @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. Plugins SHOULD store simple POD data whenever + possible, and consider the possibility of state being restored much + later on a different machine. + + The `handle` pointer and `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 (for example, 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. + */ + LV2_State_Status (*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 `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 which MUST be passed as the + handle parameter to `retrieve` if it is called. + @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 `handle` pointer and `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. + */ + LV2_State_Status (*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:mapPath (@ref LV2_STATE__mapPath). */ 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 `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 plugin state. The returned value is an abstract path which MAY not - be an actual file system path; absolute_path() MUST be used to map - it to an actual path in order to use the file. - - Plugins MUST NOT make any assumptions about abstract paths except that - they can be mapped back to the absolute path of the "same" file (though - not necessarily the same original path) using absolute_path(). - - This function may only be called within the context of - LV2_State_Interface methods. The caller must free the returned value - with LV2_State_Free_Path.free_path(). - */ - 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 `handle` member of this struct. - @param abstract_path An abstract path (typically from plugin state). - @return An absolute file system path. - - The plugin MUST use this function in order to actually open or otherwise - use any paths loaded from plugin state. - - This function may only be called within the context of - LV2_State_Interface methods. The caller must free the returned value - with LV2_State_Free_Path.free_path(). - */ - char* (*absolute_path)(LV2_State_Map_Path_Handle handle, - const char* abstract_path); + /** + 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 `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 plugin state. The returned value is an abstract path which MAY not + be an actual file system path; absolute_path() MUST be used to map + it to an actual path in order to use the file. + + Plugins MUST NOT make any assumptions about abstract paths except that + they can be mapped back to the absolute path of the "same" file (though + not necessarily the same original path) using absolute_path(). + + This function may only be called within the context of + LV2_State_Interface methods. The caller must free the returned value + with LV2_State_Free_Path.free_path(). + */ + 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 `handle` member of this struct. + @param abstract_path An abstract path (typically from plugin state). + @return An absolute file system path. + + The plugin MUST use this function in order to actually open or otherwise + use any paths loaded from plugin state. + + This function may only be called within the context of + LV2_State_Interface methods. The caller must free the returned value + with LV2_State_Free_Path.free_path(). + */ + 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__makePath). */ 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 `handle` member of this struct. - @param path The path of the new file within 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 (for example, 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 must free the returned value with - LV2_State_Free_Path.free_path(). - */ - char* (*path)(LV2_State_Make_Path_Handle handle, - const char* path); + /** + 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 `handle` member of this struct. + @param path The path of the new file within 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 (for example, 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 must free the returned value with + LV2_State_Free_Path.free_path(). + */ + char* (*path)(LV2_State_Make_Path_Handle handle, const char* path); } LV2_State_Make_Path; /** Feature data for state:freePath (@ref LV2_STATE__freePath). */ typedef struct { - /** - Opaque host data. - */ - LV2_State_Free_Path_Handle handle; - - /** - Free a path returned by a state feature. - - @param handle MUST be the `handle` member of this struct. - @param path The path previously returned by a state feature. - - This function can be used by plugins to free paths allocated by the host - and returned by state features (LV2_State_Map_Path.abstract_path(), - LV2_State_Map_Path.absolute_path(), and LV2_State_Make_Path.path()). - */ - void (*free_path)(LV2_State_Free_Path_Handle handle, - char* path); + /** + Opaque host data. + */ + LV2_State_Free_Path_Handle handle; + + /** + Free a path returned by a state feature. + + @param handle MUST be the `handle` member of this struct. + @param path The path previously returned by a state feature. + + This function can be used by plugins to free paths allocated by the host + and returned by state features (LV2_State_Map_Path.abstract_path(), + LV2_State_Map_Path.absolute_path(), and LV2_State_Make_Path.path()). + */ + void (*free_path)(LV2_State_Free_Path_Handle handle, char* path); } LV2_State_Free_Path; #ifdef __cplusplus |