source/includes/lv2/dynmanifest.h

   1 /*
   2   Dynamic manifest specification for LV2
   3   Copyright 2008-2011 Stefano D'Angelo <zanga.mail@gmail.com>
   4
   5   Permission to use, copy, modify, and/or distribute this software for any
   6   purpose with or without fee is hereby granted, provided that the above
   7   copyright notice and this permission notice appear in all copies.
   8
   9   THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  10   WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11   MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  12   ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13   WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14   ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  15   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16 */
  17
  18 /**
  19    @defgroup dynmanifest Dynamic Manifest
  20
  21    Support for dynamic data generation, see
  22    <http://lv2plug.in/ns/ext/dynmanifest> for details.
  23
  24    @{
  25 */
  26
  27 #ifndef LV2_DYN_MANIFEST_H_INCLUDED
  28 #define LV2_DYN_MANIFEST_H_INCLUDED
  29
  30 #include <stdio.h>
  31
  32 #include "lv2.h"
  33
  34 #define LV2_DYN_MANIFEST_URI    "http://lv2plug.in/ns/ext/dynmanifest"  ///< http://lv2plug.in/ns/ext/dynmanifest
  35 #define LV2_DYN_MANIFEST_PREFIX LV2_DYN_MANIFEST_URI "#"                ///< http://lv2plug.in/ns/ext/dynmanifest#
  36
  37 #ifdef __cplusplus
  38 extern "C" {
  39 #endif
  40
  41 /**
  42    Dynamic manifest generator handle.
  43
  44    This handle indicates a particular status of a dynamic manifest generator.
  45    The host MUST NOT attempt to interpret it and, unlikely LV2_Handle, it is
  46    NOT even valid to compare this to NULL. The dynamic manifest generator MAY
  47    use it to reference internal data.
  48 */
  49 typedef void * LV2_Dyn_Manifest_Handle;
  50
  51 /**
  52    Generate the dynamic manifest.
  53
  54    @param handle Pointer to an uninitialized dynamic manifest generator handle.
  55
  56    @param features NULL terminated array of LV2_Feature structs which represent
  57    the features the host supports. The dynamic manifest generator may refuse to
  58    (re)generate the dynamic manifest if required features are not found here
  59    (however hosts SHOULD NOT use this as a discovery mechanism, instead of
  60    reading the static manifest file). This array must always exist; if a host
  61    has no features, it MUST pass a single element array containing NULL.
  62
  63    @return 0 on success, otherwise a non-zero error code. The host SHOULD
  64    evaluate the result of the operation by examining the returned value and
  65    MUST NOT try to interpret the value of handle.
  66 */
  67 int lv2_dyn_manifest_open(LV2_Dyn_Manifest_Handle *  handle,
  68                           const LV2_Feature *const * features);
  69
  70 /**
  71    Fetch a "list" of subject URIs described in the dynamic manifest.
  72
  73    The dynamic manifest generator has to fill the resource only with the needed
  74    triples to make the host aware of the "objects" it wants to expose. For
  75    example, if the plugin library exposes a regular LV2 plugin, it should
  76    output only a triple like the following:
  77
  78    <http://www.example.com/plugin/uri> a lv2:Plugin .
  79
  80    The objects that are elegible for exposure are those that would need to be
  81    represented by a subject node in a static manifest.
  82
  83    @param handle Dynamic manifest generator handle.
  84
  85    @param fp FILE * identifying the resource the host has to set up for the
  86    dynamic manifest generator. The host MUST pass a writable, empty resource to
  87    this function, and the dynamic manifest generator MUST ONLY perform write
  88    operations on it at the end of the stream (e.g., using only fprintf(),
  89    fwrite() and similar).
  90
  91    @return 0 on success, otherwise a non-zero error code.
  92 */
  93 int lv2_dyn_manifest_get_subjects(LV2_Dyn_Manifest_Handle handle,
  94                                   FILE *                  fp);
  95
  96 /**
  97    Function that fetches data related to a specific URI.
  98
  99    The dynamic manifest generator has to fill the resource with data related to
 100    object represented by the given URI. For example, if the library exposes a
 101    regular LV2 plugin whose URI, as retrieved by the host using
 102    lv2_dyn_manifest_get_subjects() is http://www.example.com/plugin/uri, it
 103    should output something like:
 104
 105    <pre>
 106    <http://www.example.com/plugin/uri>
 107        a lv2:Plugin ;
 108        doap:name "My Plugin" ;
 109        lv2:binary <mylib.so> ;
 110        etc:etc "..." .
 111    </pre>
 112
 113    @param handle Dynamic manifest generator handle.
 114
 115    @param fp FILE * identifying the resource the host has to set up for the
 116    dynamic manifest generator. The host MUST pass a writable resource to this
 117    function, and the dynamic manifest generator MUST ONLY perform write
 118    operations on it at the current position of the stream (e.g. using only
 119    fprintf(), fwrite() and similar).
 120
 121    @param uri URI to get data about (in the "plain" form, i.e., absolute URI
 122    without Turtle prefixes).
 123
 124    @return 0 on success, otherwise a non-zero error code.
 125 */
 126 int lv2_dyn_manifest_get_data(LV2_Dyn_Manifest_Handle handle,
 127                               FILE *                  fp,
 128                               const char *            uri);
 129
 130 /**
 131    Function that ends the operations on the dynamic manifest generator.
 132
 133    This function SHOULD be used by the dynamic manifest generator to perform
 134    cleanup operations, etc.
 135
 136    Once this function is called, referring to handle will cause undefined
 137    behavior.
 138
 139    @param handle Dynamic manifest generator handle.
 140 */
 141 void lv2_dyn_manifest_close(LV2_Dyn_Manifest_Handle handle);
 142
 143 #ifdef __cplusplus
 144 }
 145 #endif
 146
 147 #endif /* LV2_DYN_MANIFEST_H_INCLUDED */
 148
 149 /**
 150    @}
 151 */