85 lines
3.5 KiB
Turtle
85 lines
3.5 KiB
Turtle
@prefix dman: <http://lv2plug.in/ns/ext/dynmanifest#> .
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@prefix lv2: <http://lv2plug.in/ns/lv2core#> .
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@prefix owl: <http://www.w3.org/2002/07/owl#> .
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@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
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@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
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@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
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<http://lv2plug.in/ns/ext/dynmanifest>
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a lv2:Specification ;
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rdfs:seeAlso <dynmanifest.h> ,
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<lv2-dynmanifest.doap.ttl> ;
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lv2:documentation """
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<p>The LV2 API, on its own, cannot be used to write plugin libraries where data
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is dynamically generated at runtime (e.g. API wrappers), since LV2 requires
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needed information to be provided in one or more static data (RDF) files. This
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API addresses this limitation by extending the LV2 API.</p>
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<p>To detect that a plugin library implements a dynamic manifest generator,
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the host checks its static manifest for a description like:</p>
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<pre class="turtle-code">
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<http://example.org/my-dynamic-manifest>
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a dman:DynManifest ;
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lv2:binary <mydynmanifest.so> .
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</pre>
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<p>To load the data, the host loads the library
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(e.g. <code>mydynmanifest.so</code>) as usual and fetches the dynamic Turtle
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data from it using this API.</p>
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<p>The host is allowed to request regeneration of the dynamic manifest multiple
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times, and the plugin library is expected to provide updated data if/when
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possible. All data and references provided via this API before the last
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regeneration of the dynamic manifest is to be considered invalid by the host,
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including plugin descriptors whose URIs were discovered using this API.</p>
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<h3>Accessing Data</h3>
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<p>Whenever a host wants to access data using this API, it could:</p>
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<ol>
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<li>Call lv2_dyn_manifest_open().</li>
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<li>Create a FILE for functions to write data to (e.g. using tmpfile()).</li>
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<li>Get a <q>list</q> of exposed subject URIs using
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lv2_dyn_manifest_get_subjects().</li>
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<li>Call lv2_dyn_manifest_get_data() for each URI of interest to
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get the data related to that URI (which can be written to any FILE).</li>
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<li>Call lv2_dyn_manifest_close().</li>
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<li>Parse the content of the FILE(s).</li>
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<li>Free/delete/unlink the FILE(s).</li>
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</ol>
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<p>Each call to the above mentioned dynamic manifest functions MUST write a
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complete, valid Turtle document (including all needed prefix definitions) to
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the output FILE.</p>
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<p>Each call to lv2_dyn_manifest_open() causes the (re)generation of the
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dynamic manifest data, and invalidates all data fetched before the call.</p>
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<p>In case the plugin library uses this same API to access other dynamic
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manifests, it MUST implement some mechanism to avoid potentially endless loops
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(such as A loads B, B loads A, etc.) and, in case such a loop is detected, the
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operation MUST fail. For this purpose, use of a static boolean flag is
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suggested.</p>
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<h3>Threading Rules</h3>
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<p>All of the functions defined by this specification belong to the Discovery
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class.</p>
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""" .
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dman:DynManifest
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a rdfs:Class ;
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rdfs:label "Dynamic Manifest" ;
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rdfs:subClassOf [
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a owl:Restriction ;
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owl:onProperty lv2:binary ;
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owl:minCardinality 1 ;
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rdfs:comment "A DynManifest MUST have at least 1 lv2:binary, which MUST implement all the functions defined in dynmanifest.h."
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] ;
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rdfs:comment """The class which represents a dynamic manifest generator.
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There MUST NOT be any instances of dman:DynManifest in the generated manifest.
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All relative URIs in the generated data MUST be relative to the base path that would be used to parse a normal LV2 manifest (the bundle path).""" .
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