Tell a wrapped plugin which format it is in, and which host

[baconpaul]

A CLAP inside clap-wrapper can't currently tell that it is wrapped, or as what. host->name only half answers who the host is: it carries a (CLAP-as-VST3) style suffix, the Apple formats add a version, and an AUv3 gets the name of its own appex.

This adds a host extension, clap-wrapper.host-information/0 in include/clapwrapper/wrapper_host.h, which every wrapper now provides:

auto *cwh = (const clap_wrapper_host_information_t *)host->get_extension(
    host, CLAP_WRAPPER_HOST_INFORMATION);
if (cwh)
{
  if (strcmp(cwh->get_wrapper_flavor(host), CLAP_WRAPPER_HOST_FLAVOR_AUV2) == 0)
    ...
  const char *name = cwh->get_underlying_host_name(host); // "REAPER", or null
}

A null extension means a real CLAP host.

get_wrapper_flavor

One of CLAP_WRAPPER_HOST_FLAVOR_AUV2, _AUV3, _AAX, _VST3, _STANDALONE. Clap::IHost::wrapper_flavor() is pure virtual, so a new wrapper has to answer. The AAX scan-time microhost answers aax too.

get_underlying_host_name

The host's own name without the wrapper suffix, or null when it can't be known.

Wrapper	Answer
VST3	IHostApplication::getName
AAX	AAX_IController::GetHostName; null in the scan-time microhost
AUv2 / AUv3	the name of the process the plugin was loaded into; null when that is an XPC service (AUHostingService for an out of process AUv2, the appex for an AUv3)
Standalone	Wrapper Mac Standalone / Wrapper Windows Standalone / Wrapper Linux Standalone

Each wrapper stores the name before creating the plugin and never changes it, so the call is thread-safe.

host->name is deliberately unchanged. REAPER as a native CLAP host also calls itself REAPER, and a plugin special-casing that would start doing so inside the VST3. VST3 and AAX now build host->name from the stored name, so the two can't disagree.

Example

The clap-first distortion example logs its flavor (comparing against a few of the constants) and the underlying host name.

Testing

• Builds on macOS: VST3, AUv2, standalone and AAX with Ninja, AUv3 with Xcode. clang-format clean.
• VST3 validator: 47/47, and the example logs Wrapped as a VST3 / Underlying host is 'vstvalidator'.
• Not run: AUv2, AUv3, AAX or standalone at runtime, including the XPC check. Not built on Windows or Linux.

[baconpaul]

@defiantnerd as discussed. A way to tell if you are wrapped by a host query.