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

3 files changed, 250 insertions, 5 deletions

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 <zanga.mail@gmail.com>
+ * 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 <stdio.h>
+#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:
+ *
+ *   <http://www.example.com/plugin/uri> 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:
+ *
+ *   <http://www.example.com/plugin/uri> a lv2:Plugin;
+ *       lv2:binary <mylib.so>;
+ *       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 : <http://lv2plug.in/ns/lv2core#>\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*);