fix: Allow custom HttpRules for REST LROs

gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractTransportServiceStubClassComposer.java

@@ -188,6 +188,7 @@ public GapicClass generate(GapicContext context, Service service) {
     Map<String, Message> messageTypes = context.messages();
     List<Statement> classStatements =
         createClassStatements(
+            context,
             service,
             protoMethodNameToDescriptorVarExprs,
             callableClassMemberVarExprs,
@@ -278,6 +279,7 @@ protected List<Statement> createTypeRegistry(Service service) {
   }
 
   protected List<Statement> createClassStatements(
+      GapicContext context,
       Service service,
       Map<String, VariableExpr> protoMethodNameToDescriptorVarExprs,
       Map<String, VariableExpr> callableClassMemberVarExprs,
@@ -298,6 +300,9 @@ protected List<Statement> createClassStatements(
       classStatements.add(EMPTY_LINE_STATEMENT);
     }
 
+    classStatements.addAll(createOperationCustomHttpBindingsMapDeclaration(context));
+    classStatements.add(EMPTY_LINE_STATEMENT);
+
     classStatements.addAll(createClassMemberFieldDeclarations(callableClassMemberVarExprs));
     classStatements.add(EMPTY_LINE_STATEMENT);
 
@@ -307,6 +312,10 @@ protected List<Statement> createClassStatements(
     return classStatements;
   }
 
+  protected List<Statement> createOperationCustomHttpBindingsMapDeclaration(GapicContext context) {
+    return new ArrayList<>();
+  }
+
   protected List<Statement> createMethodDescriptorVariableDecls(
       Service service,
       Map<String, VariableExpr> protoMethodNameToDescriptorVarExprs,
@@ -649,6 +658,7 @@ protected List<MethodDefinition> createConstructorMethods(
     if (generateOperationsStubLogic(service)) {
       secondCtorExprs.addAll(
           createOperationsStubInitExpr(
+              context,
               service,
               thisExpr,
               operationsStubClassVarExpr,
@@ -758,6 +768,7 @@ protected List<MethodDefinition> createConstructorMethods(
   }
 
   protected List<Expr> createOperationsStubInitExpr(
+      GapicContext context,
       Service service,
       Expr thisExpr,
       VariableExpr operationsStubClassVarExpr,

gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/rest/HttpJsonServiceStubClassComposer.java

@@ -14,6 +14,7 @@
 
 package com.google.api.generator.gapic.composer.rest;
 
+import com.google.api.HttpRule;
 import com.google.api.core.InternalApi;
 import com.google.api.gax.httpjson.ApiMethodDescriptor;
 import com.google.api.gax.httpjson.ApiMethodDescriptor.MethodType;
@@ -63,6 +64,7 @@
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.BiMap;
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
 import com.google.protobuf.TypeRegistry;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -90,6 +92,29 @@ public class HttpJsonServiceStubClassComposer extends AbstractTransportServiceSt
                   .build())
           .build();
 
+  private static final VariableExpr OPERATION_CUSTOM_HTTP_BINDINGS =
+      VariableExpr.builder()
+          .setVariable(
+              Variable.builder()
+                  .setName("operationCustomHttpBindings")
+                  .setType(FIXED_REST_TYPESTORE.get(ImmutableMap.class.getSimpleName()))
+                  .build())
+          .build();
+
+  private static final String LRO_LIST_OPERATIONS = "google.longrunning.Operations.ListOperations";
+  private static final String LRO_GET_OPERATION = "google.longrunning.Operations.GetOperation";
+  private static final String LRO_DELETE_OPERATION =
+          "google.longrunning.Operations.DeleteOperation";
+  private static final String LRO_CANCEL_OPERATION =
+          "google.longrunning.Operations.CancelOperation";
+
+  private static final Map<String, Function<HttpRule, String>> HTTP_RULE_OPERATION = ImmutableMap.<String, Function<HttpRule, String>>builder()
+          .put(LRO_LIST_OPERATIONS, HttpRule::getGet)
+          .put(LRO_GET_OPERATION, HttpRule::getGet)
+          .put(LRO_DELETE_OPERATION, HttpRule::getDelete)
+          .put(LRO_CANCEL_OPERATION, HttpRule::getPost).build();
+  private static final String LRO_NAME_PREFIX = "google.longrunning.Operations";
+
   protected HttpJsonServiceStubClassComposer() {
     super(RestContext.instance());
   }
@@ -110,6 +135,7 @@ private static TypeStore createStaticTypes() {
             HttpJsonOperationSnapshot.class,
             HttpJsonStubCallableFactory.class,
             Map.class,
+            ImmutableMap.class,
             ProtoMessageRequestFormatter.class,
             ProtoMessageResponseParser.class,
             ProtoRestSerializer.class,
@@ -121,6 +147,65 @@ protected boolean generateOperationsStubLogic(Service service) {
     return service.hasLroMethods();
   }
 
+  @Override
+  protected List<Statement> createOperationCustomHttpBindingsMapDeclaration(GapicContext context) {
+    VariableExpr operationCustomHttpBindingsVarExpr =
+        VariableExpr.withVariable(
+                Variable.builder()
+                    .setType(
+                        TypeNode.withReference(
+                            ConcreteReference.builder()
+                                .setClazz(Map.class)
+                                .setGenerics(
+                                    Arrays.asList(
+                                        ConcreteReference.withClazz(String.class),
+                                        ConcreteReference.withClazz(String.class)))
+                                .build()))
+                    .setName("operationCustomHttpBindings")
+                    .build())
+            .toBuilder()
+            .setIsDecl(true)
+            .setIsStatic(true)
+            .setScope(ScopeNode.PRIVATE)
+            .setIsFinal(true)
+            .build();
+
+    Expr operationCustomHttpBindingsBuilderExpr =
+        MethodInvocationExpr.builder()
+            .setStaticReferenceType(FIXED_REST_TYPESTORE.get(ImmutableMap.class.getSimpleName()))
+            .setMethodName("builder")
+            .setGenerics(Arrays.asList(TypeNode.STRING.reference(), TypeNode.STRING.reference()))
+            .build();
+
+    for (Map.Entry<String, String> entrySet : parseCustomHttpBindings(context).entrySet()) {
+      String selector = entrySet.getKey();
+      String path = entrySet.getValue();
+      operationCustomHttpBindingsBuilderExpr =
+          MethodInvocationExpr.builder()
+              .setExprReferenceExpr(operationCustomHttpBindingsBuilderExpr)
+              .setMethodName("put")
+              .setArguments(
+                  Arrays.asList(
+                      ValueExpr.withValue(StringObjectValue.withValue(selector)),
+                      ValueExpr.withValue(StringObjectValue.withValue(path))))
+              .build();
+    }
+
+    operationCustomHttpBindingsBuilderExpr =
+        MethodInvocationExpr.builder()
+            .setExprReferenceExpr(operationCustomHttpBindingsBuilderExpr)
+            .setMethodName("build")
+            .setReturnType(FIXED_REST_TYPESTORE.get(ImmutableMap.class.getSimpleName()))
+            .build();
+
+    return Collections.singletonList(
+        ExprStatement.withExpr(
+            AssignmentExpr.builder()
+                .setVariableExpr(operationCustomHttpBindingsVarExpr)
+                .setValueExpr(operationCustomHttpBindingsBuilderExpr)
+                .build()));
+  }
+
   @Override
   protected Statement createMethodDescriptorVariableDecl(
       Service service,
@@ -1075,6 +1160,7 @@ private List<Expr> getMethodTypeExpr(Method protoMethod) {
 
   @Override
   protected List<Expr> createOperationsStubInitExpr(
+      GapicContext context,
       Service service,
       Expr thisExpr,
       VariableExpr operationsStubClassVarExpr,
@@ -1088,6 +1174,7 @@ protected List<Expr> createOperationsStubInitExpr(
     if (standardOpStub.equals(operationsStubType.reference().fullName())) {
       arguments.add(TYPE_REGISTRY_VAR_EXPR);
     }
+    arguments.add(OPERATION_CUSTOM_HTTP_BINDINGS);
 
     return Collections.singletonList(
         AssignmentExpr.builder()
@@ -1103,6 +1190,20 @@ protected List<Expr> createOperationsStubInitExpr(
             .build());
   }
 
+  private Map<String, String> parseCustomHttpBindings(GapicContext context) {
+    Map<String, String> customHttpBindings = new HashMap<>();
+    com.google.api.Service service = context.serviceYamlProto();
+    if (service != null && service.getHttp() != null) {
+      for (HttpRule httpRule : service.getHttp().getRulesList()) {
+        String selector = httpRule.getSelector();
+        if (selector.contains(LRO_NAME_PREFIX)) {
+          customHttpBindings.put(selector, HTTP_RULE_OPERATION.get(selector).apply(httpRule));
+        }
+      }
+    }
+    return customHttpBindings;
+  }
+
   @Override
   protected List<Statement> createLongRunningClient(Service service, TypeStore typeStore) {
     Method pollingMethod = service.operationPollingMethod();

gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/HttpJsonEchoStub.golden

@@ -21,6 +21,7 @@ import com.google.api.gax.rpc.ClientContext;
 import com.google.api.gax.rpc.OperationCallable;
 import com.google.api.gax.rpc.ServerStreamingCallable;
 import com.google.api.gax.rpc.UnaryCallable;
+import com.google.common.collect.ImmutableMap;
 import com.google.longrunning.Operation;
 import com.google.protobuf.TypeRegistry;
 import com.google.showcase.grpcrest.v1beta1.BlockRequest;
@@ -330,6 +331,9 @@ public class HttpJsonEchoStub extends EchoStub {
                   .build())
           .build();
 
+  private static final Map<String, String> operationCustomHttpBindings =
+      ImmutableMap.<String, String>builder().build();
+
   private final UnaryCallable<EchoRequest, EchoResponse> echoCallable;
   private final ServerStreamingCallable<ExpandRequest, EchoResponse> expandCallable;
   private final UnaryCallable<PagedExpandRequest, PagedExpandResponse> pagedExpandCallable;
@@ -382,7 +386,8 @@ public class HttpJsonEchoStub extends EchoStub {
       throws IOException {
     this.callableFactory = callableFactory;
     this.httpJsonOperationsStub =
-        HttpJsonOperationsStub.create(clientContext, callableFactory, typeRegistry);
+        HttpJsonOperationsStub.create(
+            clientContext, callableFactory, typeRegistry, operationCustomHttpBindings);
 
     HttpJsonCallSettings<EchoRequest, EchoResponse> echoTransportSettings =
         HttpJsonCallSettings.<EchoRequest, EchoResponse>newBuilder()

gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonComplianceStub.golden

@@ -12,6 +12,7 @@ import com.google.api.gax.httpjson.ProtoMessageResponseParser;
 import com.google.api.gax.httpjson.ProtoRestSerializer;
 import com.google.api.gax.rpc.ClientContext;
 import com.google.api.gax.rpc.UnaryCallable;
+import com.google.common.collect.ImmutableMap;
 import com.google.protobuf.TypeRegistry;
 import com.google.showcase.v1beta1.EnumRequest;
 import com.google.showcase.v1beta1.EnumResponse;
@@ -350,6 +351,9 @@ public class HttpJsonComplianceStub extends ComplianceStub {
                   .build())
           .build();
 
+  private static final Map<String, String> operationCustomHttpBindings =
+      ImmutableMap.<String, String>builder().build();
+
   private final UnaryCallable<RepeatRequest, RepeatResponse> repeatDataBodyCallable;
   private final UnaryCallable<RepeatRequest, RepeatResponse> repeatDataBodyInfoCallable;
   private final UnaryCallable<RepeatRequest, RepeatResponse> repeatDataQueryCallable;