Add DefaultInstanceMessageLiteFactory

PiperOrigin-RevId: 734716485

Author: l46kok

common/internal/BUILD.bazel

@@ -57,6 +57,11 @@ java_library(
     exports = ["//common/src/main/java/dev/cel/common/internal:default_instance_message_factory"],
 )
 
+java_library(
+    name = "default_instance_message_lite_factory",
+    exports = ["//common/src/main/java/dev/cel/common/internal:default_instance_message_lite_factory"],
+)
+
 java_library(
     name = "well_known_proto",
     exports = ["//common/src/main/java/dev/cel/common/internal:well_known_proto"],

common/src/main/java/dev/cel/common/internal/BUILD.bazel

@@ -136,13 +136,25 @@ java_library(
     tags = [
     ],
     deps = [
+        ":default_instance_message_lite_factory",
+        ":proto_java_qualified_names",
         "//common/annotations",
-        "@maven//:com_google_guava_guava",
         "@maven//:com_google_protobuf_protobuf_java",
     ],
 )
 
-# keep sorted
+java_library(
+    name = "default_instance_message_lite_factory",
+    srcs = ["DefaultInstanceMessageLiteFactory.java"],
+    tags = [
+    ],
+    deps = [
+        ":reflection_util",
+        "//common/annotations",
+        "@maven//:com_google_guava_guava",
+        "@maven//:com_google_protobuf_protobuf_java",
+    ],
+)
 
 java_library(
     name = "dynamic_proto",
@@ -274,3 +286,22 @@ java_library(
         "@maven//:com_google_re2j_re2j",
     ],
 )
+
+java_library(
+    name = "proto_java_qualified_names",
+    srcs = ["ProtoJavaQualifiedNames.java"],
+    tags = [
+    ],
+    deps = [
+        "@maven//:com_google_guava_guava",
+        "@maven//:com_google_protobuf_protobuf_java",
+    ],
+)
+
+java_library(
+    name = "reflection_util",
+    srcs = ["ReflectionUtil.java"],
+    deps = [
+        "//common/annotations",
+    ],
+)

common/src/main/java/dev/cel/common/internal/DefaultInstanceMessageFactory.java

@@ -14,23 +14,11 @@
 
 package dev.cel.common.internal;
 
-import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.CaseFormat;
-import com.google.common.base.Joiner;
-import com.google.common.base.Strings;
-import com.google.common.io.Files;
-import com.google.protobuf.DescriptorProtos.FileOptions;
 import com.google.protobuf.Descriptors.Descriptor;
-import com.google.protobuf.Descriptors.EnumDescriptor;
-import com.google.protobuf.Descriptors.FileDescriptor;
-import com.google.protobuf.Descriptors.ServiceDescriptor;
 import com.google.protobuf.Message;
+import com.google.protobuf.MessageLite;
 import dev.cel.common.annotations.Internal;
-import java.lang.reflect.InvocationTargetException;
-import java.util.ArrayDeque;
-import java.util.Map;
 import java.util.Optional;
-import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * Singleton factory for creating default messages from a protobuf descriptor.
@@ -39,19 +27,11 @@
  */
 @Internal
 public final class DefaultInstanceMessageFactory {
-
-  // Controls how many times we should recursively inspect a nested message for building fully
-  // qualified java class name before aborting.
-  public static final int SAFE_RECURSE_LIMIT = 50;
-
-  private static final DefaultInstanceMessageFactory instance = new DefaultInstanceMessageFactory();
-
-  private final Map<String, LazyGeneratedMessageDefaultInstance> messageByDescriptorName =
-      new ConcurrentHashMap<>();
+  private static final DefaultInstanceMessageFactory INSTANCE = new DefaultInstanceMessageFactory();
 
   /** Gets a single instance of this MessageFactory */
   public static DefaultInstanceMessageFactory getInstance() {
-    return instance;
+    return INSTANCE;
   }
 
   /**
@@ -63,182 +43,29 @@ public static DefaultInstanceMessageFactory getInstance() {
    *     descriptor class isn't loaded in the binary.
    */
   public Optional<Message> getPrototype(Descriptor descriptor) {
-    String descriptorName = descriptor.getFullName();
-    LazyGeneratedMessageDefaultInstance lazyDefaultInstance =
-        messageByDescriptorName.computeIfAbsent(
-            descriptorName,
-            (unused) ->
-                new LazyGeneratedMessageDefaultInstance(
-                    getFullyQualifiedJavaClassName(descriptor)));
-
-    Message defaultInstance = lazyDefaultInstance.getDefaultInstance();
+    MessageLite defaultInstance =
+        DefaultInstanceMessageLiteFactory.getInstance()
+            .getPrototype(
+                descriptor.getFullName(),
+                ProtoJavaQualifiedNames.getFullyQualifiedJavaClassName(descriptor))
+            .orElse(null);
     if (defaultInstance == null) {
       return Optional.empty();
     }
-    // Reference equality is intended. We want to make sure the descriptors are equal
-    // to guarantee types to be hermetic if linked types is disabled.
-    if (defaultInstance.getDescriptorForType() != descriptor) {
-      return Optional.empty();
-    }
-    return Optional.of(defaultInstance);
-  }
-
-  /**
-   * Retrieves the full Java class name from the given descriptor
-   *
-   * @return fully qualified class name.
-   *     <p>Example 1: dev.cel.expr.Value
-   *     <p>Example 2: com.google.rpc.context.AttributeContext$Resource (Nested classes)
-   *     <p>Example 3: com.google.api.expr.cel.internal.testdata$SingleFileProto$SingleFile$Path
-   *     (Nested class with java multiple files disabled)
-   */
-  private String getFullyQualifiedJavaClassName(Descriptor descriptor) {
-    StringBuilder fullClassName = new StringBuilder();
 
-    fullClassName.append(getJavaPackageName(descriptor));
-
-    String javaOuterClass = getJavaOuterClassName(descriptor);
-    if (!Strings.isNullOrEmpty(javaOuterClass)) {
-      fullClassName.append(javaOuterClass).append("$");
-    }
-
-    // Recursively build the target class name in case if the message is nested.
-    ArrayDeque<String> classNames = new ArrayDeque<>();
-    Descriptor d = descriptor;
-
-    int recurseCount = 0;
-    while (d != null) {
-      classNames.push(d.getName());
-      d = d.getContainingType();
-      recurseCount++;
-      if (recurseCount >= SAFE_RECURSE_LIMIT) {
-        throw new IllegalStateException(
-            String.format(
-                "Recursion limit of %d hit while inspecting descriptor: %s",
-                SAFE_RECURSE_LIMIT, descriptor.getFullName()));
-      }
-    }
-
-    Joiner.on("$").appendTo(fullClassName, classNames);
-
-    return fullClassName.toString();
-  }
-
-  /**
-   * Gets the java package name from the descriptor. See
-   * https://developers.google.com/protocol-buffers/docs/reference/java-generated#package for rules
-   * on package name generation
-   */
-  private String getJavaPackageName(Descriptor descriptor) {
-    FileOptions options = descriptor.getFile().getOptions();
-    StringBuilder javaPackageName = new StringBuilder();
-    if (options.hasJavaPackage()) {
-      javaPackageName.append(descriptor.getFile().getOptions().getJavaPackage()).append(".");
-    } else {
-      javaPackageName
-          // CEL-Internal-1
-          .append(descriptor.getFile().getPackage())
-          .append(".");
+    if (!(defaultInstance instanceof Message)) {
+      throw new IllegalArgumentException(
+          "Expected a full protobuf message, but got: " + defaultInstance.getClass());
     }
 
-    // CEL-Internal-2
+    Message fullMessage = (Message) defaultInstance;
 
-    return javaPackageName.toString();
-  }
-
-  /**
-   * Gets a wrapping outer class name from the descriptor. The outer class name differs depending on
-   * the proto options set. See
-   * https://developers.google.com/protocol-buffers/docs/reference/java-generated#invocation
-   */
-  private String getJavaOuterClassName(Descriptor descriptor) {
-    FileOptions options = descriptor.getFile().getOptions();
-
-    if (options.getJavaMultipleFiles()) {
-      // If java_multiple_files is enabled, protoc does not generate a wrapper outer class
-      return "";
-    }
-
-    if (options.hasJavaOuterClassname()) {
-      return options.getJavaOuterClassname();
-    } else {
-      // If an outer class name is not explicitly set, the name is converted into
-      // Pascal case based on the snake cased file name
-      // Ex: messages_proto.proto becomes MessagesProto
-      String protoFileNameWithoutExtension =
-          Files.getNameWithoutExtension(descriptor.getFile().getFullName());
-      String outerClassName =
-          CaseFormat.LOWER_UNDERSCORE.to(CaseFormat.UPPER_CAMEL, protoFileNameWithoutExtension);
-      if (hasConflictingClassName(descriptor.getFile(), outerClassName)) {
-        outerClassName += "OuterClass";
-      }
-      return outerClassName;
-    }
-  }
-
-  private boolean hasConflictingClassName(FileDescriptor file, String name) {
-    for (EnumDescriptor enumDesc : file.getEnumTypes()) {
-      if (name.equals(enumDesc.getName())) {
-        return true;
-      }
-    }
-    for (ServiceDescriptor serviceDesc : file.getServices()) {
-      if (name.equals(serviceDesc.getName())) {
-        return true;
-      }
-    }
-    for (Descriptor messageDesc : file.getMessageTypes()) {
-      if (name.equals(messageDesc.getName())) {
-        return true;
-      }
-    }
-    return false;
-  }
-
-  /** A placeholder to lazily load the generated messages' defaultInstances. */
-  private static final class LazyGeneratedMessageDefaultInstance {
-    private final String fullClassName;
-    private volatile Message defaultInstance = null;
-    private volatile boolean loaded = false;
-
-    public LazyGeneratedMessageDefaultInstance(String fullClassName) {
-      this.fullClassName = fullClassName;
-    }
-
-    public Message getDefaultInstance() {
-      if (!loaded) {
-        synchronized (this) {
-          if (!loaded) {
-            loadDefaultInstance();
-            loaded = true;
-          }
-        }
-      }
-      return defaultInstance;
-    }
-
-    private void loadDefaultInstance() {
-      try {
-        defaultInstance =
-            (Message) Class.forName(fullClassName).getMethod("getDefaultInstance").invoke(null);
-      } catch (IllegalAccessException | InvocationTargetException e) {
-        throw new LinkageError(
-            String.format("getDefaultInstance for class: %s failed.", fullClassName), e);
-      } catch (NoSuchMethodException e) {
-        throw new LinkageError(
-            String.format("getDefaultInstance method does not exist in class: %s.", fullClassName),
-            e);
-      } catch (ClassNotFoundException e) {
-        // The class may not exist in some instances (Ex: evaluating a checked expression from a
-        // cached source).
-      }
+    // Reference equality is intended. We want to make sure the descriptors are equal
+    // to guarantee types to be hermetic if linked types is disabled.
+    if (fullMessage.getDescriptorForType() != descriptor) {
+      return Optional.empty();
     }
-  }
-
-  /** Clears the descriptor map. This should not be used outside testing. */
-  @VisibleForTesting
-  void resetDescriptorMapForTesting() {
-    messageByDescriptorName.clear();
+    return Optional.of(fullMessage);
   }
 
   private DefaultInstanceMessageFactory() {}