Bug 1722833 - Add nsCocoaFeatures::OnMontereyOrLater(). r=mac-reviewers,spohl

Depends on D128616

Differential Revision: https://phabricator.services.mozilla.com/D128785

toolkit/xre/MacRunFromDmgUtils.mm

@@ -425,7 +425,7 @@ bool IsAppRunningFromDmg() {
     return false;
   }
   const char* imageClass =
-      nsCocoaFeatures::macOSVersionMajor() >= 12 ? "AppleDiskImageDevice" : "IOHDIXHDDrive";
+      nsCocoaFeatures::OnMontereyOrLater() ? "AppleDiskImageDevice" : "IOHDIXHDDrive";
   for (imageDrive = media; imageDrive; imageDrive = IOIteratorNext(iter)) {
     if (IOObjectConformsTo(imageDrive, imageClass)) {
       break;

widget/cocoa/nsCocoaFeatures.h

@@ -23,6 +23,7 @@ class nsCocoaFeatures {
   static bool OnMojaveOrLater();
   static bool OnCatalinaOrLater();
   static bool OnBigSurOrLater();
+  static bool OnMontereyOrLater();
 
   static bool IsAtLeastVersion(int32_t aMajor, int32_t aMinor,
                                int32_t aBugFix = 0);

widget/cocoa/nsCocoaFeatures.mm

@@ -24,6 +24,7 @@
 #define MACOS_VERSION_10_15_HEX 0x000A0F00
 #define MACOS_VERSION_10_16_HEX 0x000A1000
 #define MACOS_VERSION_11_0_HEX 0x000B0000
+#define MACOS_VERSION_12_0_HEX 0x000C0000
 
 #include "nsCocoaFeatures.h"
 #include "nsCocoaUtils.h"
@@ -165,12 +166,29 @@ bool Gecko_OnSierraExactly() { return nsCocoaFeatures::OnSierraExactly(); }
 }
 
 /* static */ bool nsCocoaFeatures::OnBigSurOrLater() {
-  // Account for the version being 10.16 (which occurs when the
-  // application is linked with an older SDK) or 11.0 on Big Sur.
+  // Account for the version being 10.16 or 11.0 on Big Sur.
+  // The version is reported as 10.16 if SYSTEM_VERSION_COMPAT is set to 1,
+  // or if SYSTEM_VERSION_COMPAT is not set and the application is linked
+  // with a pre-Big Sur SDK.
+  // Firefox sets SYSTEM_VERSION_COMPAT to 0 in its Info.plist, so it'll
+  // usually see the correct 11.* version, despite being linked against an
+  // old SDK. However, it still sees the 10.16 compatibility version when
+  // launched from the command line, see bug 1727624. (This only applies to
+  // the Intel build - the arm64 build is linked against a Big Sur SDK and
+  // always sees the correct version.)
   return ((macOSVersion() >= MACOS_VERSION_10_16_HEX) ||
           (macOSVersion() >= MACOS_VERSION_11_0_HEX));
 }
 
+/* static */ bool nsCocoaFeatures::OnMontereyOrLater() {
+  // This check only works if SYSTEM_VERSION_COMPAT is off, otherwise
+  // Monterey pretends to be 10.16 and is indistinguishable from Big Sur.
+  // In practice, this means that an Intel Firefox build can return false
+  // from this function if it's launched from the command line, see bug 1727624.
+  // This will not be an issue anymore once we link against the Big Sur SDK.
+  return (macOSVersion() >= MACOS_VERSION_12_0_HEX);
+}
+
 /* static */ bool nsCocoaFeatures::IsAtLeastVersion(int32_t aMajor, int32_t aMinor,
                                                     int32_t aBugFix) {
   return macOSVersion() >= GetVersion(aMajor, aMinor, aBugFix);