Add SPI method to process endpoint properties

This will allow extracting things like auth schemes and other AWS
specific properties.

Author: mtdowling

client/client-rulesengine/src/main/java/software/amazon/smithy/java/client/rulesengine/RulesCompiler.java

@@ -34,6 +34,7 @@
 
 final class RulesCompiler {
 
+    private final List<RulesExtension> extensions;
     private final EndpointRuleSet rules;
 
     private final Map<Object, Integer> constantPool = new LinkedHashMap<>();
@@ -66,11 +67,13 @@ final class RulesCompiler {
     private int temporaryRegisters = 0;
 
     RulesCompiler(
+            List<RulesExtension> extensions,
             EndpointRuleSet rules,
             Map<String, RulesFunction> functions,
             BiFunction<String, Context, Object> builtinProvider,
             boolean performOptimizations
     ) {
+        this.extensions = extensions;
         this.rules = rules;
         this.builtinProvider = builtinProvider;
         this.performOptimizations = performOptimizations;
@@ -433,6 +436,7 @@ RulesProgram buildProgram() {
         var constPool = new Object[this.constantPool.size()];
         constantPool.keySet().toArray(constPool);
         return new RulesProgram(
+                extensions,
                 this.instructions,
                 0,
                 instructionSize,

client/client-rulesengine/src/main/java/software/amazon/smithy/java/client/rulesengine/RulesEngine.java

@@ -30,6 +30,7 @@ public final class RulesEngine {
         }
     }
 
+    private final List<RulesExtension> extensions = new ArrayList<>();
     private final Map<String, RulesFunction> functions = new LinkedHashMap<>();
     private final List<BiFunction<String, Context, Object>> builtinProviders = new ArrayList<>();
     private boolean performOptimizations = true;
@@ -82,6 +83,7 @@ public RulesEngine addBuiltinProvider(BiFunction<String, Context, Object> builti
      * @return the RulesEngine.
      */
     public RulesEngine addExtension(RulesExtension extension) {
+        extensions.add(extension);
         addBuiltinProvider(extension.getBuiltinProvider());
         for (var f : extension.getFunctions()) {
             addFunction(f);
@@ -120,7 +122,7 @@ private BiFunction<String, Context, Object> createBuiltinProvider() {
      * @return the compiled program.
      */
     public RulesProgram compile(EndpointRuleSet rules) {
-        return new RulesCompiler(rules, functions, createBuiltinProvider(), performOptimizations).compile();
+        return new RulesCompiler(extensions, rules, functions, createBuiltinProvider(), performOptimizations).compile();
     }
 
     /**
@@ -191,6 +193,7 @@ public RulesProgram build() {
             }
 
             return new RulesProgram(
+                    extensions,
                     bytecode.array(),
                     bytecode.arrayOffset() + bytecode.position(),
                     bytecode.remaining(),

client/client-rulesengine/src/main/java/software/amazon/smithy/java/client/rulesengine/RulesExtension.java

@@ -6,7 +6,9 @@
 package software.amazon.smithy.java.client.rulesengine;
 
 import java.util.List;
+import java.util.Map;
 import java.util.function.BiFunction;
+import software.amazon.smithy.java.client.core.endpoint.Endpoint;
 import software.amazon.smithy.java.context.Context;
 
 /**
@@ -30,4 +32,21 @@ default BiFunction<String, Context, Object> getBuiltinProvider() {
     default List<RulesFunction> getFunctions() {
         return List.of();
     }
+
+    /**
+     * Allows processing a resolved endpoint, extracting properties, and updating the endpoint builder.
+     *
+     * @param builder The endpoint being created. Modify this based on properties and headers.
+     * @param context The context provided when resolving the endpoint. The endpoint has its own context properties.
+     * @param properties The raw properties returned from the endpoint resolver. Process these to update the builder.
+     * @param headers The headers returned from the endpoint resolver. Process these if needed.
+     */
+    default void extractEndpointProperties(
+            Endpoint.Builder builder,
+            Context context,
+            Map<String, Object> properties,
+            Map<String, List<String>> headers
+    ) {
+        // by default does nothing.
+    }
 }

client/client-rulesengine/src/main/java/software/amazon/smithy/java/client/rulesengine/RulesProgram.java

@@ -147,6 +147,7 @@ public final class RulesProgram {
      */
     static final byte RETURN_VALUE = 17;
 
+    final List<RulesExtension> extensions;
     final Object[] constantPool;
     final byte[] instructions;
     final int instructionOffset;
@@ -157,6 +158,7 @@ public final class RulesProgram {
     private final int paramCount; // number of provided params.
 
     RulesProgram(
+            List<RulesExtension> extensions,
             byte[] instructions,
             int instructionOffset,
             int instructionSize,
@@ -165,6 +167,7 @@ public final class RulesProgram {
             BiFunction<String, Context, Object> builtinProvider,
             final Object[] constantPool
     ) {
+        this.extensions = extensions;
         this.instructions = instructions;
         this.instructionOffset = instructionOffset;
         this.instructionSize = instructionSize;

client/client-rulesengine/src/main/java/software/amazon/smithy/java/client/rulesengine/RulesVm.java

@@ -32,6 +32,7 @@ protected boolean removeEldestEntry(Map.Entry<String, URI> eldest) {
         };
     });
 
+    private final Context context;
     private final RulesProgram program;
     private final Object[] registers;
     private final BiFunction<String, Context, Object> builtinProvider;
@@ -46,6 +47,7 @@ protected boolean removeEldestEntry(Map.Entry<String, URI> eldest) {
             Map<String, Object> parameters,
             BiFunction<String, Context, Object> builtinProvider
     ) {
+        this.context = context;
         this.program = program;
         this.instructions = program.instructions;
         this.builtinProvider = builtinProvider;
@@ -258,11 +260,10 @@ private Endpoint setEndpoint(boolean hasProperties, boolean hasHeaders) {
             builder.putProperty(Endpoint.HEADERS, headers);
         }
 
-        for (var _e : properties.entrySet()) {
-            // TODO: map properties to endpoint properties.
+        for (var extension : program.extensions) {
+            extension.extractEndpointProperties(builder, context, properties, headers);
         }
 
-        // TODO: Add auth schemes and figure out how to map properties there too.
         return builder.build();
     }