From a45145ae3d8c0b6522ee2bc8f2e16564ea396cce Mon Sep 17 00:00:00 2001
From: Marc Durdin <marc@durdin.net>
Date: Wed, 23 Nov 2022 09:25:11 +1100
Subject: [PATCH] fix(mac): Caps processing was not consistent with core

Fixes #7632.

If Caps Lock was on, rules that did not specify Caps Lock state were
not matched, for example:

```
+ [K_SLASH] > 'foo'
```

The truth table for matches is:

Event    |    Rule     | Result
---------|-------------|-----------
NCAPS    |    0        | match
NCAPS    |    CAPS     | no match
NCAPS    |    NCAPS    | match
CAPS     |    0        | match
CAPS     |    CAPS     | match
CAPS     |    NCAPS    | no match

(Internally, Keyman for Mac currently maps 0 to NCAPS on the event for
simplicity.)

The fix is to ignore the Event Caps Lock state if the rule specifies
neither `CAPS` nor `NCAPS`. If the rule specifies either of these
state masks, then the Caps component of the state mask must match.
---
 .../KeymanEngine4Mac/KME/KMBinaryFileFormat.h            | 1 +
 mac/KeymanEngine4Mac/KeymanEngine4Mac/KME/KMEngine.m     | 9 ++++++---
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/mac/KeymanEngine4Mac/KeymanEngine4Mac/KME/KMBinaryFileFormat.h b/mac/KeymanEngine4Mac/KeymanEngine4Mac/KME/KMBinaryFileFormat.h
index 60d394be71..17483dabd2 100644
--- a/mac/KeymanEngine4Mac/KeymanEngine4Mac/KME/KMBinaryFileFormat.h
+++ b/mac/KeymanEngine4Mac/KeymanEngine4Mac/KME/KMBinaryFileFormat.h
@@ -144,6 +144,7 @@ struct COMP_STORE {
 #define ISVIRTUALKEY    0x4000      // It is a Virtual Key Sequence
 #define VIRTUALCHARKEY  0x8000      // Keyman 6.0: Virtual Key Cap Sequence
 #define K_MODIFIERFLAG  0x007F
+#define K_CAPITALMASK (CAPITALFLAG|NOTCAPITALFLAG)
 
 struct COMP_KEY {
     WORD Key;  // Windows VK code or character value (VIRTUALCHARKEY, ISVIRTUALKEY)
diff --git a/mac/KeymanEngine4Mac/KeymanEngine4Mac/KME/KMEngine.m b/mac/KeymanEngine4Mac/KeymanEngine4Mac/KME/KMEngine.m
index 293799915a..40ad2678f2 100644
--- a/mac/KeymanEngine4Mac/KeymanEngine4Mac/KME/KMEngine.m
+++ b/mac/KeymanEngine4Mac/KeymanEngine4Mac/KME/KMEngine.m
@@ -278,8 +278,7 @@ const NSString* kEasterEggKmxName = @"EnglishSpanish.kmx";
                 DWORD kMask = mask;
                 if (self.debugMode)
                     NSLog(@"Has shift flags: %X", key.shiftFlags);
-                //DWORD flags = key.shiftFlags & 0x0FFF;
-                if ((key.shiftFlags & NOTCAPITALFLAG) && !(kMask & CAPITALFLAG))
+                if ((kMask & CAPITALFLAG) == 0)
                     kMask |= NOTCAPITALFLAG;
                 if ((key.shiftFlags & K_CTRLFLAG) && (kMask & LCTRLFLAG)) {
                     kMask |= K_CTRLFLAG;
@@ -305,7 +304,11 @@ const NSString* kEasterEggKmxName = @"EnglishSpanish.kmx";
                     NSLog(@"mFlag = %X", mFlag);
                     NSLog(@"mMask = %X", mMask);
                 }
-                if ((kMask & CAPITALFLAG && key.shiftFlags & CAPITALFLAG) || (!(kMask & CAPITALFLAG) && !(key.shiftFlags & CAPITALFLAG))) {
+                // If key.shiftFlags has neither CAPITALMASK nor NOTCAPITALMASK,
+                // we ignore Caps state, otherwise Caps state must match
+                // precisely
+                if ((key.shiftFlags & K_CAPITALMASK) == 0 || 
+                        (key.shiftFlags & K_CAPITALMASK) == (kMask & K_CAPITALMASK)) {
                     if (mMask == mFlag) {
                         if (!key.context.length) {
                             mKey = key;