Hide node layout of BDD and move domain to trait

Rather than have the Bdd class contain Condition, Results, Parameters,
etc, it now just deals with nodes. It also now hides the implementation
detail of how the BDD nodes are laid out internally. BDD evaluation
is internalized to the BDD as well rather than a separate BddEvaluator.
This change provides faster evaluation, makes it possible to change
the internal node data layout if necessary, and cleans up all the
interacts we had with BddTrait (no need to always reach into Bdd).

Author: mtdowling

smithy-aws-endpoints/src/main/java/software/amazon/smithy/rulesengine/aws/validators/RuleSetAwsBuiltInValidator.java

@@ -14,7 +14,7 @@
 import software.amazon.smithy.model.validation.ValidationEvent;
 import software.amazon.smithy.rulesengine.aws.language.functions.AwsBuiltIns;
 import software.amazon.smithy.rulesengine.language.syntax.parameters.Parameter;
-import software.amazon.smithy.rulesengine.traits.BddTrait;
+import software.amazon.smithy.rulesengine.logic.bdd.BddTrait;
 import software.amazon.smithy.rulesengine.traits.EndpointRuleSetTrait;
 import software.amazon.smithy.utils.SetUtils;
 
@@ -39,7 +39,7 @@ public List<ValidationEvent> validate(Model model) {
         }
 
         for (ServiceShape s : model.getServiceShapesWithTrait(BddTrait.class)) {
-            validateRuleSetAwsBuiltIns(events, s, s.expectTrait(BddTrait.class).getBdd().getParameters());
+            validateRuleSetAwsBuiltIns(events, s, s.expectTrait(BddTrait.class).getParameters());
         }
 
         return events;

smithy-rules-engine/src/main/java/software/amazon/smithy/rulesengine/language/evaluation/RuleEvaluator.java

@@ -27,7 +27,7 @@
 import software.amazon.smithy.rulesengine.language.syntax.rule.RuleValueVisitor;
 import software.amazon.smithy.rulesengine.logic.RuleBasedConditionEvaluator;
 import software.amazon.smithy.rulesengine.logic.bdd.Bdd;
-import software.amazon.smithy.rulesengine.logic.bdd.BddEvaluator;
+import software.amazon.smithy.rulesengine.logic.bdd.BddTrait;
 import software.amazon.smithy.utils.SmithyUnstableApi;
 
 /**
@@ -50,34 +50,57 @@ public static Value evaluate(EndpointRuleSet ruleset, Map<Identifier, Value> par
         return new RuleEvaluator().evaluateRuleSet(ruleset, parameterArguments);
     }
 
+    /**
+     * Initializes a new {@link RuleEvaluator} instances, and evaluates the provided BDD and parameter arguments.
+     *
+     * @param trait The trait to evaluate.
+     * @param args The rule-set parameter identifiers and values to evaluate the BDD against.
+     * @return The resulting value from the final matched rule.
+     */
+    public static Value evaluate(BddTrait trait, Map<Identifier, Value> args) {
+        return evaluate(trait.getBdd(), trait.getParameters(), trait.getConditions(), trait.getResults(), args);
+    }
+
     /**
      * Initializes a new {@link RuleEvaluator} instances, and evaluates the provided BDD and parameter arguments.
      *
      * @param bdd The endpoint bdd.
      * @param parameterArguments The rule-set parameter identifiers and values to evaluate the BDD against.
      * @return The resulting value from the final matched rule.
      */
-    public static Value evaluate(Bdd bdd, Map<Identifier, Value> parameterArguments) {
-        return new RuleEvaluator().evaluateBdd(bdd, parameterArguments);
+    public static Value evaluate(
+            Bdd bdd,
+            Parameters parameters,
+            List<Condition> conditions,
+            List<Rule> results,
+            Map<Identifier, Value> parameterArguments
+    ) {
+        return new RuleEvaluator().evaluateBdd(bdd, parameters, conditions, results, parameterArguments);
     }
 
-    private Value evaluateBdd(Bdd bdd, Map<Identifier, Value> parameterArguments) {
+    private Value evaluateBdd(
+            Bdd bdd,
+            Parameters parameters,
+            List<Condition> conditions,
+            List<Rule> results,
+            Map<Identifier, Value> parameterArguments
+    ) {
         return scope.inScope(() -> {
-            for (Parameter parameter : bdd.getParameters()) {
+            for (Parameter parameter : parameters) {
                 parameter.getDefault().ifPresent(value -> scope.insert(parameter.getName(), value));
             }
 
             parameterArguments.forEach(scope::insert);
-            BddEvaluator evaluator = BddEvaluator.from(bdd);
-            Condition[] conds = bdd.getConditions().toArray(new Condition[0]);
+
+            Condition[] conds = conditions.toArray(new Condition[0]);
             RuleBasedConditionEvaluator conditionEvaluator = new RuleBasedConditionEvaluator(this, conds);
-            int result = evaluator.evaluate(conditionEvaluator);
+            int result = bdd.evaluate(conditionEvaluator);
 
-            if (result <= 0) {
+            if (result < 0) {
                 throw new RuntimeException("No BDD result matched");
             }
 
-            Rule rule = bdd.getResults().get(result);
+            Rule rule = results.get(result);
             if (rule instanceof EndpointRule) {
                 return resolveEndpoint(this, ((EndpointRule) rule).getEndpoint());
             } else if (rule instanceof ErrorRule) {

smithy-rules-engine/src/main/java/software/amazon/smithy/rulesengine/language/evaluation/TestEvaluator.java

@@ -13,7 +13,7 @@
 import software.amazon.smithy.rulesengine.language.evaluation.value.EndpointValue;
 import software.amazon.smithy.rulesengine.language.evaluation.value.Value;
 import software.amazon.smithy.rulesengine.language.syntax.Identifier;
-import software.amazon.smithy.rulesengine.logic.bdd.Bdd;
+import software.amazon.smithy.rulesengine.logic.bdd.BddTrait;
 import software.amazon.smithy.rulesengine.traits.EndpointTestCase;
 import software.amazon.smithy.rulesengine.traits.EndpointTestExpectation;
 import software.amazon.smithy.rulesengine.traits.ExpectedEndpoint;
@@ -40,12 +40,12 @@ public static void evaluate(EndpointRuleSet ruleset, EndpointTestCase testCase)
     }
 
     /**
-     * Evaluate the given rule-set and test case. Throws an exception in the event the test case does not pass.
+     * Evaluate the given BDD and test case. Throws an exception in the event the test case does not pass.
      *
-     * @param bdd      The BDD to be tested.
+     * @param bdd      The BDD trait to be tested.
      * @param testCase The test case.
      */
-    public static void evaluate(Bdd bdd, EndpointTestCase testCase) {
+    public static void evaluate(BddTrait bdd, EndpointTestCase testCase) {
         Value result = RuleEvaluator.evaluate(bdd, createParams(testCase));
         processResult(result, testCase);
     }