From 7c38c56d726a1a1f8119e4e03cc9a07ef720a84d Mon Sep 17 00:00:00 2001 From: David Robillard Date: Sun, 14 Jun 2009 22:38:29 +0000 Subject: Add missing lv2_dyn_manifest.h. Update for dynamic manifest extension to use LV2_Feature directly. git-svn-id: http://svn.drobilla.net/lad/trunk/slv2@2106 a436a847-0d15-0410-975c-d299462d15a1 --- src/lv2_dyn_manifest.h | 246 +++++++++++++++++++++++++++++++++++++++++++++++++ src/slv2_internal.h | 2 +- src/world.c | 7 +- 3 files changed, 250 insertions(+), 5 deletions(-) create mode 100644 src/lv2_dyn_manifest.h (limited to 'src') diff --git a/src/lv2_dyn_manifest.h b/src/lv2_dyn_manifest.h new file mode 100644 index 0000000..f15f6f4 --- /dev/null +++ b/src/lv2_dyn_manifest.h @@ -0,0 +1,246 @@ +/* + * Dynamic manifest specification for LV2 + * Revision 1 + * + * Copyright (C) 2008, 2009 Stefano D'Angelo + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef LV2_DYN_MANIFEST_H_INCLUDED +#define LV2_DYN_MANIFEST_H_INCLUDED + +#include +#include "lv2.h" + +#ifdef __cplusplus +extern "C" { +#endif + + +/* ************************************************************************* */ + + +/** @file lv2_dyn_manifest.h + * + * Revision: 1 + * + * == Overview == + * + * The LV2 API, on its own, cannot be used to write plugin libraries where + * data is dynamically generated at runtime (e.g. API wrappers), since LV2 + * requires needed information to be provided in one or more static data (RDF) + * files. This API adds to the LV2 API and tries to address this limitation. + * + * A host implementing support for this API should first detect that the plugin + * library implements a dynamic manifest generator by examining its static + * manifest file, then fetch data from the shared object file by accessing it as + * usual (dlopen() and family) and using this API. + * + * The host is allowed to request regeneration of the dynamic manifest multiple + * times, and the plugin library is expected to provide updated data if/when + * possible. All data and references provided via this API before the last + * regeneration of the dynamic manifest is to be considered invalid by the + * host, including plugin descriptors whose URIs were discovered using this API. + * + * Furthermore, this API itself is extensible in a similar fashion as the LV2 + * API and contains very limited error-handling. + * + * == Threading rules == + * + * This specification defines threading rule classes, similarly to the LV2 + * specification. + * + * The functions defined by this API belong to: + * + * - Dynamic manifest open class: lv2_dyn_manifest_open() + * - Dynamic manifest close class: lv2_dyn_manifest_close() + * - Dynamic manifest file class: lv2_dyn_manifest_get_subjects(), + * lv2_dyn_manifest_get_data() + * + * The rules that hosts must follow are these: + * + * - When a function from the Dynamic manifest open or the Dynamic manifest + * close class is running, no other functions in the same shared object file + * may run. + * - When a function from the Dynamic manifest file class is called, no other + * functions from the same class may run if they are given at least one + * FILE * argument with the same value. + * - A function from the Dynamic manifest open class may not run after a + * successful call to a function from the same class, in case a function from + * the Dynamic manifest close class was not successfully called in the + * meanwhile. + * - A function from the Dynamic manifest close class may only run after a + * successful call to a function from the Dynamic manifest open class. + * - A function from the Dynamic manifest file class may only run beetween a + * successful call to a function from the Dynamic manifest open class and the + * following successful call to a function from the Dynamic manifest close + * class. + * + * Extensions to this specification which add new functions MUST declare in + * which of these classes the functions belong, or define new classes for them; + * furthermore, classes defined by such extensions MUST only allow calls after + * a successful call to a function from the Dynamic manifest open class and + * before the following successful call to a function from the Dynamic manifest + * close class. + * + * Any simultaneous calls that are not explicitly forbidden by these rules are + * allowed. + */ + + +/* ************************************************************************* */ + + +/** Dynamic manifest generator handle. + * + * This handle indicates a particular status of a dynamic manifest generator. + * The host MUST NOT attempt to interpret it and, unlikely LV2_Handle, it is NOT + * even valid to compare this to NULL. The dynamic manifest generator may use it + * to reference internal data. */ +typedef void * LV2_Dyn_Manifest_Handle; + + +/* ************************************************************************* */ + + +/** Accessing data. + * + * Whenever a host wants to access data using this API, it could: + * + * 1. Call lv2_dyn_manifest_open(); + * 2. Create an empty resource identified by a FILE *; + * 3. Get a "list" of exposed subject URIs using + * lv2_dyn_manifest_get_subjects(); + * 4. Call lv2_dyn_manifest_get_data() for each URI of interest, in order to + * get data related to that URI (either by calling the function subsequently + * with the same FILE * resource, or by creating more FILE * resources to + * perform parallel calls); + * 5. Call lv2_dyn_manifest_close(); + * 6. Parse the content of the FILE * resource(s). + * 7. Free/delete/unlink the FILE * resource(s). + * + * The content of the FILE * resources has to be interpreted by the host as a + * regular file in Turtle syntax. This also means that each FILE * resource + * should also contain needed prefix definitions, in case any are used. + * + * Each call to lv2_dyn_manifest_open() automatically implies the (re)generation + * of the dynamic manifest on the library side. + * + * When such calls are made, data fetched from the involved library using this + * API before such call is to be considered no more valid. + * + * In case the library uses this same API to access other dynamic manifests, it + * MUST implement some mechanism to avoid potentially endless loops (such as A + * loads B, B loads A, etc.) in functions from the Dynamic manifest open class + * (the open-like operation MUST fail). For this purpose, use of a static + * boolean flag is suggested. + */ + +/** Function that (re)generates the dynamic manifest. + * + * handle is a pointer to an uninitialized dynamic manifest generator handle. + * + * features is a NULL terminated array of LV2_Feature structs which + * represent the features the host supports. The dynamic manifest geenrator may + * refuse to (re)generate the dynamic manifest if required features are not + * found here (however hosts SHOULD NOT use this as a discovery mechanism, + * instead of reading the static manifest file). This array must always exist; + * if a host has no features, it MUST pass a single element array containing + * NULL. + * + * This function MUST return 0 on success, otherwise a non-zero error code, and + * the host SHOULD evaluate the result of the operation by examining the + * returned value, rather than try to interpret the value of handle. + */ +int lv2_dyn_manifest_open(LV2_Dyn_Manifest_Handle * handle, + const LV2_Feature *const * features); + +/** Function that fetches a "list" of subject URIs exposed by the dynamic + * manifest generator. + * + * handle is the dynamic manifest generator handle. + * + * fp is the FILE * identifying the resource the host has to set up for the + * dynamic manifest generator. The host MUST pass a writable, empty resource to + * this function, and the dynamic manifest generator MUST ONLY perform write + * operations on it at the end of the stream (e.g. use only fprintf(), fwrite() + * and similar). + * + * The dynamic manifest generator has to fill the resource only with the needed + * triples to make the host aware of the "objects" it wants to expose. For + * example, if the library exposes a regular LV2 plugin, it should output only a + * triple like the following: + * + * a lv2:Plugin; + * + * This function MUST return 0 on success, otherwise a non-zero error code. + */ +int lv2_dyn_manifest_get_subjects(LV2_Dyn_Manifest_Handle handle, + FILE * fp); + +/** Function that fetches data related to a specific URI. + * + * handle is the dynamic manifest generator handle. + * + * fp is the FILE * identifying the resource the host has to set up for the + * dynamic manifest generator. The host MUST pass a writable resource to this + * function, and the dynamic manifest generator MUST ONLY perform write + * operations on it at the current position of the stream (e.g. use only + * fprintf(), fwrite() and similar). + * + * uri is the URI to get data about (in the "plain" form, a.k.a. without RDF + * prefixes). + * + * The dynamic manifest generator has to fill the resource with data related to + * the URI. For example, if the library exposes a regular LV2 plugin whose URI, + * as retrieved by the host using lv2_dyn_manifest_get_subjects() is + * http://www.example.com/plugin/uri, it should output something like: + * + * a lv2:Plugin; + * lv2:binary ; + * doap:name "My Plugin"; + * ... etc... + * + * This function MUST return 0 on success, otherwise a non-zero error code. + */ +int lv2_dyn_manifest_get_data(LV2_Dyn_Manifest_Handle handle, + FILE * fp, + const char * uri); + +/** Function that ends the operations on the dynamic manifest generator. + * + * handle is the dynamic manifest generator handle. + * + * This function should be used by the dynamic manifest generator to perform + * cleanup operations, etc. + */ +void lv2_dyn_manifest_close(LV2_Dyn_Manifest_Handle handle); + +#ifdef __cplusplus +} +#endif + +#endif /* LV2_DYN_MANIFEST_H_INCLUDED */ + diff --git a/src/slv2_internal.h b/src/slv2_internal.h index 1b2c785..4202b92 100644 --- a/src/slv2_internal.h +++ b/src/slv2_internal.h @@ -257,7 +257,7 @@ char* slv2_get_lang(); /* ********* Dynamic Manifest ********* */ #ifdef SLV2_DYN_MANIFEST -static const LV2_Dyn_Manifest_Feature* const dman_features = { NULL }; +static const LV2_Feature* const dman_features = { NULL }; #endif #define SLV2_ERROR(str) fprintf(stderr, "ERROR: %s: " str, __func__) diff --git a/src/world.c b/src/world.c index b99ee35..4d004d9 100644 --- a/src/world.c +++ b/src/world.c @@ -207,8 +207,7 @@ slv2_world_load_bundle(SLV2World world, SLV2Value bundle_uri) manifest_model); #ifdef SLV2_DYN_MANIFEST - LV2_Dyn_Manifest_Handle handle = NULL; - const LV2_Dyn_Manifest_Feature* const features = { NULL }; + LV2_Dyn_Manifest_Handle handle = NULL; const unsigned char* const query_str = (const unsigned char* const) "PREFIX : \n" @@ -236,10 +235,10 @@ slv2_world_load_bundle(SLV2World world, SLV2Value bundle_uri) continue; // Open dynamic manifest - typedef int (*OpenFunc)(LV2_Dyn_Manifest_Handle*, const LV2_Dyn_Manifest_Feature *const *); + typedef int (*OpenFunc)(LV2_Dyn_Manifest_Handle*, const LV2_Feature *const *); OpenFunc open_func = (OpenFunc)dlsym(lib, "lv2_dyn_manifest_open"); if (open_func) - open_func(&handle, &features); + open_func(&handle, &dman_features); // Get subjects (the data that would be in manifest.ttl) typedef int (*GetSubjectsFunc)(LV2_Dyn_Manifest_Handle, FILE*); -- cgit v1.2.1