AST: Move AvailabilityConstraint implementation to a separate file.

lib/AST/AvailabilityConstraint.cpp

@@ -0,0 +1,53 @@
+//===--- AvailabilityConstraint.cpp - Swift Availability Constraints ------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/AST/AvailabilityConstraint.h"
+#include "swift/AST/ASTContext.h"
+
+using namespace swift;
+
+PlatformKind AvailabilityConstraint::getPlatform() const {
+  return getAttr().getPlatform();
+}
+
+std::optional<AvailabilityRange>
+AvailabilityConstraint::getRequiredNewerAvailabilityRange(
+    ASTContext &ctx) const {
+  switch (getKind()) {
+  case Kind::AlwaysUnavailable:
+  case Kind::RequiresVersion:
+  case Kind::Obsoleted:
+    return std::nullopt;
+  case Kind::IntroducedInNewerVersion:
+    return getAttr().getIntroducedRange(ctx);
+  }
+}
+
+bool AvailabilityConstraint::isConditionallySatisfiable() const {
+  switch (getKind()) {
+  case Kind::AlwaysUnavailable:
+  case Kind::RequiresVersion:
+  case Kind::Obsoleted:
+    return false;
+  case Kind::IntroducedInNewerVersion:
+    return true;
+  }
+}
+
+bool AvailabilityConstraint::isActiveForRuntimeQueries(ASTContext &ctx) const {
+  if (getAttr().getPlatform() == PlatformKind::none)
+    return true;
+
+  return swift::isPlatformActive(getAttr().getPlatform(), ctx.LangOpts,
+                                 /*forTargetVariant=*/false,
+                                 /*forRuntimeQuery=*/true);
+}