Resolved issue: NETTY-258 (Make DynamicChannelBuffer.ensureWritableBytes() public)

* Added ChannelBuffer.ensureWritableBytes(int)

src/main/java/org/jboss/netty/buffer/AbstractChannelBuffer.java

@@ -116,6 +116,12 @@ public abstract class AbstractChannelBuffer implements ChannelBuffer {
         readerIndex = 0;
     }
 
+    public void ensureWritableBytes(int writableBytes) {
+        if (writableBytes > writableBytes()) {
+            throw new IndexOutOfBoundsException();
+        }
+    }
+
     public short getUnsignedByte(int index) {
         return (short) (getByte(index) & 0xFF);
     }

src/main/java/org/jboss/netty/buffer/ChannelBuffer.java

@@ -413,6 +413,28 @@ public interface ChannelBuffer extends Comparable<ChannelBuffer> {
      */
     void discardReadBytes();
 
+    /**
+     * Makes sure the number of {@linkplain #writableBytes() the writable bytes}
+     * is equal to or greater than the specified value.  If there is enough
+     * writable bytes in this buffer, this method returns with no side effect.
+     * Otherwise:
+     * <ul>
+     * <li>a non-dynamic buffer will throw an {@link IndexOutOfBoundsException}.</li>
+     * <li>a dynamic buffer will expand its capacity so that the number of the
+     *     {@link #writableBytes() writable bytes} becomes equal to or greater
+     *     than the specified value. The expansion involves the reallocation of
+     *     the internal buffer and consequently memory copy.</li>
+     * </ul>
+     *
+     * @param writableBytes
+     *        the expected minimum number of writable bytes
+     * @throws IndexOutOfBoundsException
+     *         if {@linkplain #writableBytes() the writable bytes} of this
+     *         buffer is less than the specified value and the capacity of the
+     *         buffer cannot be expanded
+     */
+    void ensureWritableBytes(int writableBytes);
+
     /**
      * Gets a byte at the specified absolute {@code index} in this buffer.
      * This method does not modify {@code readerIndex} or {@code writerIndex} of

src/main/java/org/jboss/netty/buffer/DynamicChannelBuffer.java

@@ -64,6 +64,28 @@ public class DynamicChannelBuffer extends AbstractChannelBuffer {
         buffer = factory.getBuffer(order(), estimatedLength);
     }
 
+    @Override
+    public void ensureWritableBytes(int minWritableBytes) {
+        if (minWritableBytes <= writableBytes()) {
+            return;
+        }
+
+        int newCapacity;
+        if (capacity() == 0) {
+            newCapacity = 1;
+        } else {
+            newCapacity = capacity();
+        }
+        int minNewCapacity = writerIndex() + minWritableBytes;
+        while (newCapacity < minNewCapacity) {
+            newCapacity <<= 1;
+        }
+
+        ChannelBuffer newBuffer = factory().getBuffer(order(), newCapacity);
+        newBuffer.writeBytes(buffer, 0, writerIndex());
+        buffer = newBuffer;
+    }
+
     public ChannelBufferFactory factory() {
         return factory;
     }
@@ -271,25 +293,4 @@ public class DynamicChannelBuffer extends AbstractChannelBuffer {
     public String toString(int index, int length, String charsetName) {
         return buffer.toString(index, length, charsetName);
     }
-
-    private void ensureWritableBytes(int requestedBytes) {
-        if (requestedBytes <= writableBytes()) {
-            return;
-        }
-
-        int newCapacity;
-        if (capacity() == 0) {
-            newCapacity = 1;
-        } else {
-            newCapacity = capacity();
-        }
-        int minNewCapacity = writerIndex() + requestedBytes;
-        while (newCapacity < minNewCapacity) {
-            newCapacity <<= 1;
-        }
-
-        ChannelBuffer newBuffer = factory().getBuffer(order(), newCapacity);
-        newBuffer.writeBytes(buffer, 0, writerIndex());
-        buffer = newBuffer;
-    }
 }

src/main/java/org/jboss/netty/handler/codec/replay/ReplayingDecoderBuffer.java

@@ -95,6 +95,10 @@ class ReplayingDecoderBuffer implements ChannelBuffer {
         throw new UnreplayableOperationException();
     }
 
+    public void ensureWritableBytes(int writableBytes) {
+        throw new UnreplayableOperationException();
+    }
+
     public ChannelBuffer duplicate() {
         throw new UnreplayableOperationException();
     }