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[3.7.5] Module Info and Plug-in Compatibility

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Introduction

A new moduleinfo.json file added to the plug-in bundle (in the Resources folder) describes the contents of the plug-in in a JSON5 compatible format. This includes a compatibility list which allows, for example, a VST 3 plug-in to replace a given VST 2 plug-in (check here, to learn how to create UID for old VST 1/VST 2 plug-ins).

  • [plug imp]
  • [released: 3.7.5]

Plug-in’s module info file: moduleinfo.json

Check moduleinfo.json for more information about the content of this file.

IPluginCompatibility

If the plug-in could not deliver the moduleinfo.json because it is not organized as a bundle-like package, it is possible to add the new interface IPluginCompatibility to the plug-in factory.

ⓘ Note
If the compatibility feature is required, it is recommended to use either moduleinfo.json or IPluginCompatibility.

ⓘ Note
It is not recommended to implement IPluginCompatibility if you do not provide compatibility with any previous plug-in version. If you expose this object, the host expects you to provide compatibility information with it; otherwise, it is useless.

Example

In plugentry.cpp:

//------------------------------------------------------------------------
class PluginCompatibility : public FObject, public IPluginCompatibility
{
  public:
    //...
    tresult PLUGIN_API getCompatibilityJSON (IBStream* stream) override
    {
        // here plug-in with UID BD58B550F9E5634E9D2EFF39EA0927B1 could replace 
        // plug-in with UID AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA and
        // plug-in with UID BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
      /* write the JSON compatibility array into the stream
      [
          {
              "New": "BD58B550F9E5634E9D2EFF39EA0927B1",
              "Old": [
                  "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
                  "BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB",
              ],
          }
      ]
      */
	    return kResultTrue;
    }
    //... 
};

//------------------------------------------------------------------------
static FUnknown* createCompatibilityInstance (void* context)
{
	return (IPluginCompatibility*)new PluginCompatibility;
}

//------------------------------------------------------------------------
BEGIN_FACTORY_DEF (stringCompanyName, stringCompanyWeb, stringCompanyEmail)

    //...
    DEF_CLASS2 (INLINE_UID_FROM_FUID(PluginCompatibilityUID),
				PClassInfo::kManyInstances,
				kPluginCompatibilityClass,
				stringPluginName,
				Vst::kDistributable,
				"",
				FULL_VERSION_STR,
				kVstVersionString,
				createCompatibilityInstance)

Example of host implementation

Check function void Validator::testModule in public.sdk/samples/vst-hosting/validator/source/validator.cpp.

plugCompatibility = factory.createInstance<IPluginCompatibility> (classInfo.ID ());