Throw Base64DataException instead of IOException

* Define Base64DataException
* Throw it from Base64InputStream & Base64OutputStream
* This enables callers to disambiguate "bad data" from "broken stream",
  which makes it more possible to do proper retry logic.

Bug: 3365205
Change-Id: I332e7c008f92b333400d1b4dcaef5aedc7c10ef4

3 files changed, 32 insertions, 2 deletions

diff --git a/core/java/android/util/Base64DataException.java b/core/java/android/util/Base64DataException.java
new file mode 100644
index 0000000..de12ee1
--- /dev/null
+++ b/core/java/android/util/Base64DataException.java
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.util;
+
+import java.io.IOException;
+
+/**
+ * This exception is thrown by {@link Base64InputStream} or {@link Base64OutputStream}
+ * when an error is detected in the data being decoded.  This allows problems with the base64 data
+ * to be disambiguated from errors in the underlying streams (e.g. actual connection errors.)
+ */
+public class Base64DataException extends IOException {
+    public Base64DataException(String detailMessage) {
+        super(detailMessage);
+    }
+}
diff --git a/core/java/android/util/Base64InputStream.java b/core/java/android/util/Base64InputStream.java
index e9dac24..9eba5b5 100644
--- a/core/java/android/util/Base64InputStream.java
+++ b/core/java/android/util/Base64InputStream.java
@@ -145,7 +145,7 @@ public class Base64InputStream extends FilterInputStream {
             success = coder.process(inputBuffer, 0, bytesRead, false);
         }
         if (!success) {
-            throw new IOException("bad base-64");
+            throw new Base64DataException("bad base-64");
         }
         outputEnd = coder.op;
         outputStart = 0;
diff --git a/core/java/android/util/Base64OutputStream.java b/core/java/android/util/Base64OutputStream.java
index 30d632d..4535d1c 100644
--- a/core/java/android/util/Base64OutputStream.java
+++ b/core/java/android/util/Base64OutputStream.java
@@ -136,7 +136,7 @@ public class Base64OutputStream extends FilterOutputStream {
     private void internalWrite(byte[] b, int off, int len, boolean finish) throws IOException {
         coder.output = embiggen(coder.output, coder.maxOutputSize(len));
         if (!coder.process(b, off, len, finish)) {
-            throw new IOException("bad base-64");
+            throw new Base64DataException("bad base-64");
         }
         out.write(coder.output, 0, coder.op);
     }