From ffe4642aa5c35cb61801a7bc1d4ee25b84bccd9b Mon Sep 17 00:00:00 2001
From: Robbert van der Helm <mail@robbertvanderhelm.nl>
Date: Sat, 7 May 2022 13:24:17 +0200
Subject: [PATCH] Implement IProcessContextRequirements

This is needed for VST 3.7. We claim to be a VST 3.6.14 plugin, but
implementing this anyways seems like the safe bet. I doubt many hosts
would, but under VST 3.7 hosts are allowed to not send any transport
information unless this interface is implemented.
---
 src/wrapper/vst3/factory.rs |  3 ++-
 src/wrapper/vst3/wrapper.rs | 19 ++++++++++++++++---
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/src/wrapper/vst3/factory.rs b/src/wrapper/vst3/factory.rs
index 17733808..00cc828f 100644
--- a/src/wrapper/vst3/factory.rs
+++ b/src/wrapper/vst3/factory.rs
@@ -13,7 +13,8 @@ use super::wrapper::Wrapper;
 use crate::plugin::Vst3Plugin;
 use crate::wrapper::util::strlcpy;
 
-/// The VST3 SDK version this is roughtly based on.
+/// The VST3 SDK version this is roughtly based on. The bindings include some VST 3.7 things but not
+/// everything, so we'll play it safe.
 const VST3_SDK_VERSION: &str = "VST 3.6.14";
 
 #[doc(hidden)]
diff --git a/src/wrapper/vst3/wrapper.rs b/src/wrapper/vst3/wrapper.rs
index cb49a89c..2f25963a 100644
--- a/src/wrapper/vst3/wrapper.rs
+++ b/src/wrapper/vst3/wrapper.rs
@@ -4,15 +4,16 @@ use std::mem::{self, MaybeUninit};
 use std::ptr;
 use std::sync::atomic::Ordering;
 use std::sync::Arc;
+use vst3_com::vst::IProcessContextRequirementsFlags;
 use vst3_sys::base::{kInvalidArgument, kNoInterface, kResultFalse, kResultOk, tresult, TBool};
 use vst3_sys::base::{IBStream, IPluginBase};
 use vst3_sys::utils::SharedVstPtr;
 use vst3_sys::vst::{
     kNoParamId, kNoParentUnitId, kNoProgramListId, kRootUnitId, Event, EventTypes, IAudioProcessor,
     IComponent, IEditController, IEventList, IMidiMapping, INoteExpressionController,
-    IParamValueQueue, IParameterChanges, IUnitInfo, LegacyMidiCCOutEvent, NoteExpressionTypeInfo,
-    NoteExpressionValueDescription, NoteOffEvent, NoteOnEvent, ParameterFlags, PolyPressureEvent,
-    ProgramListInfo, TChar, UnitInfo,
+    IParamValueQueue, IParameterChanges, IProcessContextRequirements, IUnitInfo,
+    LegacyMidiCCOutEvent, NoteExpressionTypeInfo, NoteExpressionValueDescription, NoteOffEvent,
+    NoteOnEvent, ParameterFlags, PolyPressureEvent, ProgramListInfo, TChar, UnitInfo,
 };
 use vst3_sys::VST3;
 use widestring::U16CStr;
@@ -42,6 +43,7 @@ use vst3_sys as vst3_com;
     IAudioProcessor,
     IMidiMapping,
     INoteExpressionController,
+    IProcessContextRequirements,
     IUnitInfo
 ))]
 pub(crate) struct Wrapper<P: Vst3Plugin> {
@@ -1406,6 +1408,17 @@ impl<P: Vst3Plugin> INoteExpressionController for Wrapper<P> {
     }
 }
 
+impl<P: Vst3Plugin> IProcessContextRequirements for Wrapper<P> {
+    unsafe fn get_process_context_requirements(&self) -> u32 {
+        IProcessContextRequirementsFlags::kNeedProjectTimeMusic
+            | IProcessContextRequirementsFlags::kNeedBarPositionMusic
+            | IProcessContextRequirementsFlags::kNeedCycleMusic
+            | IProcessContextRequirementsFlags::kNeedTimeSignature
+            | IProcessContextRequirementsFlags::kNeedTempo
+            | IProcessContextRequirementsFlags::kNeedTransportState
+    }
+}
+
 impl<P: Vst3Plugin> IUnitInfo for Wrapper<P> {
     unsafe fn get_unit_count(&self) -> i32 {
         self.inner.param_units.len() as i32