Remove AuthProperties and just use Context

Rather than essentially recreate Context for Auth and Identity related
properties, we can just use Context. AuthProperties already used
Context.Key, but recreated most of Context in order to be immutable.
This isn't strictly necessary given Context can be made immutable using
Context.unmodifiableView(ctx).

In order to make this change, we needed to add a few missing methods to
Context that are good additions: merge (merge two contexts and return a
new context), getOrDefault, and Context.empty (return an immutable and
empty context).

Author: mtdowling

Diff for: auth-api/src/main/java/software/amazon/smithy/java/auth/api/AuthProperties.java

@@ -7,6 +7,7 @@
 
 import java.util.concurrent.CompletableFuture;
 import software.amazon.smithy.java.auth.api.identity.Identity;
+import software.amazon.smithy.java.context.Context;
 
 /**
  * A signer that does nothing.
@@ -30,7 +31,7 @@ private NullSigner() {}
      * @return the request as-is.
      */
     @Override
-    public CompletableFuture<Object> sign(Object request, Identity identity, AuthProperties properties) {
+    public CompletableFuture<Object> sign(Object request, Identity identity, Context properties) {
         return CompletableFuture.completedFuture(request);
     }
 }

Diff for: auth-api/src/main/java/software/amazon/smithy/java/auth/api/NullSigner.java

@@ -7,6 +7,7 @@
 
 import java.util.concurrent.CompletableFuture;
 import software.amazon.smithy.java.auth.api.identity.Identity;
+import software.amazon.smithy.java.context.Context;
 
 /**
  * Signs the given request using the given identity and returns a signed request.
@@ -24,7 +25,7 @@ public interface Signer<RequestT, IdentityT extends Identity> extends AutoClosea
      * @param properties Signing properties.
      * @return the signed request.
      */
-    CompletableFuture<RequestT> sign(RequestT request, IdentityT identity, AuthProperties properties);
+    CompletableFuture<RequestT> sign(RequestT request, IdentityT identity, Context properties);
 
     @SuppressWarnings("unchecked")
     static <RequestT, IdentityT extends Identity> Signer<RequestT, IdentityT> nullSigner() {

Diff for: auth-api/src/main/java/software/amazon/smithy/java/auth/api/Signer.java

@@ -7,7 +7,7 @@
 
 import java.util.List;
 import java.util.concurrent.CompletableFuture;
-import software.amazon.smithy.java.auth.api.AuthProperties;
+import software.amazon.smithy.java.context.Context;
 
 /**
  * Interface for loading {@link Identity} that is used for authentication.
@@ -22,7 +22,7 @@ public interface IdentityResolver<IdentityT extends Identity> {
      * @param requestProperties The request properties used to resolve an Identity.
      * @return a CompletableFuture for the resolved identity result.
      */
-    CompletableFuture<IdentityResult<IdentityT>> resolveIdentity(AuthProperties requestProperties);
+    CompletableFuture<IdentityResult<IdentityT>> resolveIdentity(Context requestProperties);
 
     /**
      * Retrieve the class of the identity resolved by this identity resolver.

Diff for: auth-api/src/main/java/software/amazon/smithy/java/auth/api/identity/IdentityResolver.java

@@ -9,7 +9,7 @@
 import java.util.List;
 import java.util.Objects;
 import java.util.concurrent.CompletableFuture;
-import software.amazon.smithy.java.auth.api.AuthProperties;
+import software.amazon.smithy.java.context.Context;
 
 final class IdentityResolverChain<IdentityT extends Identity> implements IdentityResolver<IdentityT> {
     private final Class<IdentityT> identityClass;
@@ -29,14 +29,14 @@ public Class<IdentityT> identityType() {
     }
 
     @Override
-    public CompletableFuture<IdentityResult<IdentityT>> resolveIdentity(AuthProperties requestProperties) {
+    public CompletableFuture<IdentityResult<IdentityT>> resolveIdentity(Context requestProperties) {
         List<IdentityResult<?>> errors = new ArrayList<>();
         return executeChain(resolvers.get(0), requestProperties, errors, 0);
     }
 
     private CompletableFuture<IdentityResult<IdentityT>> executeChain(
             IdentityResolver<IdentityT> resolver,
-            AuthProperties requestProperties,
+            Context requestProperties,
             List<IdentityResult<?>> errors,
             int idx
     ) {

Diff for: auth-api/src/main/java/software/amazon/smithy/java/auth/api/identity/IdentityResolverChain.java

@@ -7,7 +7,7 @@
 
 import java.util.Objects;
 import java.util.concurrent.CompletableFuture;
-import software.amazon.smithy.java.auth.api.AuthProperties;
+import software.amazon.smithy.java.context.Context;
 
 final class StaticIdentityResolver<IdentityT extends Identity> implements IdentityResolver<IdentityT> {
 
@@ -20,7 +20,7 @@ public StaticIdentityResolver(IdentityT identity) {
     }
 
     @Override
-    public CompletableFuture<IdentityResult<IdentityT>> resolveIdentity(AuthProperties requestProperties) {
+    public CompletableFuture<IdentityResult<IdentityT>> resolveIdentity(Context requestProperties) {
         return result;
     }
 

Diff for: auth-api/src/main/java/software/amazon/smithy/java/auth/api/identity/StaticIdentityResolver.java

@@ -22,9 +22,9 @@
 import org.openjdk.jmh.annotations.Scope;
 import org.openjdk.jmh.annotations.Setup;
 import org.openjdk.jmh.annotations.State;
-import software.amazon.smithy.java.auth.api.AuthProperties;
 import software.amazon.smithy.java.auth.api.Signer;
 import software.amazon.smithy.java.aws.auth.api.identity.AwsCredentialsIdentity;
+import software.amazon.smithy.java.context.Context;
 import software.amazon.smithy.java.http.api.HttpHeaders;
 import software.amazon.smithy.java.http.api.HttpRequest;
 import software.amazon.smithy.java.http.api.HttpVersion;
@@ -38,10 +38,15 @@ public class SigV4SignerTrials {
     private static final AwsCredentialsIdentity TEST_IDENTITY = AwsCredentialsIdentity.create(
             "access-key",
             "secret-key");
-    private static final AuthProperties TEST_PROPERTIES = AuthProperties.builder()
-            .put(SigV4Settings.SIGNING_NAME, "service")
-            .put(SigV4Settings.REGION, "us-east-1")
-            .build();
+
+    private static final Context TEST_PROPERTIES;
+    static {
+        var ctx = Context.create();
+        ctx.put(SigV4Settings.SIGNING_NAME, "service");
+        ctx.put(SigV4Settings.REGION, "us-east-1");
+        TEST_PROPERTIES = Context.unmodifiableView(ctx);
+    }
+
     private static final Map<String, HttpRequest> CASES = Map.ofEntries(
             Map.entry(
                     "put_no_headers_no_query_no_body",

Diff for: aws/aws-sigv4/src/jmh/java/software/amazon/smithy/java/aws/client/auth/scheme/sigv4/SigV4SignerTrials.java

@@ -6,7 +6,6 @@
 package software.amazon.smithy.java.aws.client.auth.scheme.sigv4;
 
 import software.amazon.smithy.aws.traits.auth.SigV4Trait;
-import software.amazon.smithy.java.auth.api.AuthProperties;
 import software.amazon.smithy.java.auth.api.Signer;
 import software.amazon.smithy.java.aws.auth.api.identity.AwsCredentialsIdentity;
 import software.amazon.smithy.java.client.core.auth.scheme.AuthScheme;
@@ -57,15 +56,15 @@ public Class<AwsCredentialsIdentity> identityClass() {
     }
 
     @Override
-    public AuthProperties getSignerProperties(Context context) {
-        var builder = AuthProperties.builder()
-                .put(SigV4Settings.SIGNING_NAME, signingName)
-                .put(SigV4Settings.REGION, context.expect(SigV4Settings.REGION));
+    public Context getSignerProperties(Context context) {
+        var ctx = Context.create();
+        ctx.put(SigV4Settings.SIGNING_NAME, signingName);
+        ctx.put(SigV4Settings.REGION, context.expect(SigV4Settings.REGION));
         var clock = context.get(SigV4Settings.CLOCK);
         if (clock != null) {
-            builder.put(SigV4Settings.CLOCK, clock);
+            ctx.put(SigV4Settings.CLOCK, clock);
         }
-        return builder.build();
+        return Context.unmodifiableView(ctx);
     }
 
     @Override

Diff for: aws/aws-sigv4/src/main/java/software/amazon/smithy/java/aws/client/auth/scheme/sigv4/SigV4AuthScheme.java

@@ -25,9 +25,9 @@
 import java.util.concurrent.CompletableFuture;
 import javax.crypto.Mac;
 import javax.crypto.spec.SecretKeySpec;
-import software.amazon.smithy.java.auth.api.AuthProperties;
 import software.amazon.smithy.java.auth.api.Signer;
 import software.amazon.smithy.java.aws.auth.api.identity.AwsCredentialsIdentity;
+import software.amazon.smithy.java.context.Context;
 import software.amazon.smithy.java.http.api.HttpHeaders;
 import software.amazon.smithy.java.http.api.HttpRequest;
 import software.amazon.smithy.java.io.datastream.DataStream;
@@ -101,7 +101,7 @@ public void close() {
     public CompletableFuture<HttpRequest> sign(
             HttpRequest request,
             AwsCredentialsIdentity identity,
-            AuthProperties properties
+            Context properties
     ) {
         var region = properties.expect(SigV4Settings.REGION);
         var name = properties.expect(SigV4Settings.SIGNING_NAME);