throw IOException instead of InvalidProtocolBufferException when appropriate

3 files changed, 80 insertions, 4 deletions

diff --git a/java/core/src/main/java/com/google/protobuf/GeneratedMessage.java b/java/core/src/main/java/com/google/protobuf/GeneratedMessage.java
index d84fa75c..ceb97a4e 100644
--- a/java/core/src/main/java/com/google/protobuf/GeneratedMessage.java
+++ b/java/core/src/main/java/com/google/protobuf/GeneratedMessage.java
@@ -36,15 +36,13 @@ import com.google.protobuf.Descriptors.EnumValueDescriptor;
 import com.google.protobuf.Descriptors.FieldDescriptor;
 import com.google.protobuf.Descriptors.FileDescriptor;
 import com.google.protobuf.Descriptors.OneofDescriptor;
-import com.google.protobuf.GeneratedMessageLite.ExtendableMessage;
-import com.google.protobuf.GeneratedMessageLite.GeneratedExtension;
 
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.ObjectStreamException;
 import java.io.Serializable;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
-import java.lang.reflect.Type;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Iterator;
@@ -276,6 +274,60 @@ public abstract class GeneratedMessage extends AbstractMessage
     return unknownFields.mergeFieldFrom(tag, input);
   }
 
+  protected static <M extends Message> M parseWithIOException(Parser<M> parser, InputStream input)
+      throws IOException {
+    try {
+      return parser.parseFrom(input);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  protected static <M extends Message> M parseWithIOException(Parser<M> parser, InputStream input,
+      ExtensionRegistryLite extensions) throws IOException {
+    try {
+      return parser.parseFrom(input, extensions);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  protected static <M extends Message> M parseWithIOException(Parser<M> parser,
+      CodedInputStream input) throws IOException {
+    try {
+      return parser.parseFrom(input);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  protected static <M extends Message> M parseWithIOException(Parser<M> parser,
+      CodedInputStream input, ExtensionRegistryLite extensions) throws IOException {
+    try {
+      return parser.parseFrom(input, extensions);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  protected static <M extends Message> M parseDelimitedWithIOException(Parser<M> parser,
+      InputStream input) throws IOException {
+    try {
+      return parser.parseDelimitedFrom(input);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
+  protected static <M extends Message> M parseDelimitedWithIOException(Parser<M> parser,
+      InputStream input, ExtensionRegistryLite extensions) throws IOException {
+    try {
+      return parser.parseDelimitedFrom(input, extensions);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.unwrapIOException();
+    }
+  }
+
   @Override
   public void writeTo(final CodedOutputStream output) throws IOException {
     MessageReflection.writeMessageTo(this, getAllFieldsRaw(), output, false);
@@ -667,7 +719,7 @@ public abstract class GeneratedMessage extends AbstractMessage
           "No map fields found in " + getClass().getName());
     }
 
-    /** Like {@link internalGetMapField} but return a mutable version. */
+    /** Like {@link #internalGetMapField} but return a mutable version. */
     @SuppressWarnings({"unused", "rawtypes"})
     protected MapField internalGetMutableMapField(int fieldNumber) {
       // Note that we can't use descriptor names here because this method will
diff --git a/java/core/src/main/java/com/google/protobuf/InvalidProtocolBufferException.java b/java/core/src/main/java/com/google/protobuf/InvalidProtocolBufferException.java
index 0a761052..85ce7b24 100644
--- a/java/core/src/main/java/com/google/protobuf/InvalidProtocolBufferException.java
+++ b/java/core/src/main/java/com/google/protobuf/InvalidProtocolBufferException.java
@@ -46,6 +46,10 @@ public class InvalidProtocolBufferException extends IOException {
     super(description);
   }
 
+  public InvalidProtocolBufferException(IOException e) {
+    super(e.getMessage(), e);
+  }
+
   /**
    * Attaches an unfinished message to the exception to support best-effort
    * parsing in {@code Parser} interface.
@@ -66,6 +70,14 @@ public class InvalidProtocolBufferException extends IOException {
     return unfinishedMessage;
   }
 
+  /**
+   * Unwraps the underlying {@link IOException} if this exception was caused by an I/O
+   * problem. Otherwise, returns {@code this}.
+   */
+  public IOException unwrapIOException() {
+    return getCause() instanceof IOException ? (IOException) getCause() : this;
+  }
+
   static InvalidProtocolBufferException truncatedMessage() {
     return new InvalidProtocolBufferException(
       "While parsing a protocol message, the input ended unexpectedly " +
diff --git a/java/core/src/main/java/com/google/protobuf/Parser.java b/java/core/src/main/java/com/google/protobuf/Parser.java
index 227c02b7..3fa11c3b 100644
--- a/java/core/src/main/java/com/google/protobuf/Parser.java
+++ b/java/core/src/main/java/com/google/protobuf/Parser.java
@@ -30,6 +30,7 @@
 
 package com.google.protobuf;
 
+import java.io.IOException;
 import java.io.InputStream;
 
 /**
@@ -37,9 +38,20 @@ import java.io.InputStream;
  *
  * The implementation should be stateless and thread-safe.
  *
+ * <p>All methods may throw {@link InvalidProtocolBufferException}. In the event of invalid data,
+ * like an encoding error, the cause of the thrown exception will be {@code null}. However, if an
+ * I/O problem occurs, an exception is thrown with an {@link IOException} cause.
+ *
  * @author liujisi@google.com (Pherl Liu)
  */
 public interface Parser<MessageType> {
+
+  // NB(jh): Other parts of the protobuf API that parse messages distinguish between an I/O problem
+  // (like failure reading bytes from a socket) and invalid data (encoding error) via the type of
+  // thrown exception. But it would be source-incompatible to make the methods in this interface do
+  // so since they were originally spec'ed to only throw InvalidProtocolBufferException. So callers
+  // must inspect the cause of the exception to distinguish these two cases.
+
   /**
    * Parses a message of {@code MessageType} from the input.
    *