diff options
Diffstat (limited to 'java/core/src/main/java/com/google/protobuf/ByteBufferWriter.java')
-rw-r--r-- | java/core/src/main/java/com/google/protobuf/ByteBufferWriter.java | 32 |
1 files changed, 14 insertions, 18 deletions
diff --git a/java/core/src/main/java/com/google/protobuf/ByteBufferWriter.java b/java/core/src/main/java/com/google/protobuf/ByteBufferWriter.java index 6157a52f..2cb3ada6 100644 --- a/java/core/src/main/java/com/google/protobuf/ByteBufferWriter.java +++ b/java/core/src/main/java/com/google/protobuf/ByteBufferWriter.java @@ -40,45 +40,40 @@ import java.lang.reflect.Field; import java.nio.ByteBuffer; import java.nio.channels.WritableByteChannel; -/** - * Utility class to provide efficient writing of {@link ByteBuffer}s to {@link OutputStream}s. - */ +/** Utility class to provide efficient writing of {@link ByteBuffer}s to {@link OutputStream}s. */ final class ByteBufferWriter { private ByteBufferWriter() {} /** - * Minimum size for a cached buffer. This prevents us from allocating buffers that are too - * small to be easily reused. + * Minimum size for a cached buffer. This prevents us from allocating buffers that are too small + * to be easily reused. */ // TODO(nathanmittler): tune this property or allow configuration? private static final int MIN_CACHED_BUFFER_SIZE = 1024; /** - * Maximum size for a cached buffer. If a larger buffer is required, it will be allocated - * but not cached. + * Maximum size for a cached buffer. If a larger buffer is required, it will be allocated but not + * cached. */ // TODO(nathanmittler): tune this property or allow configuration? private static final int MAX_CACHED_BUFFER_SIZE = 16 * 1024; - /** - * The fraction of the requested buffer size under which the buffer will be reallocated. - */ + /** The fraction of the requested buffer size under which the buffer will be reallocated. */ // TODO(nathanmittler): tune this property or allow configuration? private static final float BUFFER_REALLOCATION_THRESHOLD = 0.5f; /** - * Keeping a soft reference to a thread-local buffer. This buffer is used for writing a - * {@link ByteBuffer} to an {@link OutputStream} when no zero-copy alternative was available. - * Using a "soft" reference since VMs may keep this reference around longer than "weak" - * (e.g. HotSpot will maintain soft references until memory pressure warrants collection). + * Keeping a soft reference to a thread-local buffer. This buffer is used for writing a {@link + * ByteBuffer} to an {@link OutputStream} when no zero-copy alternative was available. Using a + * "soft" reference since VMs may keep this reference around longer than "weak" (e.g. HotSpot will + * maintain soft references until memory pressure warrants collection). */ private static final ThreadLocal<SoftReference<byte[]>> BUFFER = new ThreadLocal<SoftReference<byte[]>>(); - /** - * This is a hack for GAE, where {@code FileOutputStream} is unavailable. - */ + /** This is a hack for GAE, where {@code FileOutputStream} is unavailable. */ private static final Class<?> FILE_OUTPUT_STREAM_CLASS = safeGetClass("java.io.FileOutputStream"); + private static final long CHANNEL_FIELD_OFFSET = getChannelFieldOffset(FILE_OUTPUT_STREAM_CLASS); /** @@ -100,7 +95,7 @@ final class ByteBufferWriter { // Optimized write for array-backed buffers. // Note that we're taking the risk that a malicious OutputStream could modify the array. output.write(buffer.array(), buffer.arrayOffset() + buffer.position(), buffer.remaining()); - } else if (!writeToChannel(buffer, output)){ + } else if (!writeToChannel(buffer, output)) { // Read all of the data from the buffer to an array. // TODO(nathanmittler): Consider performance improvements for other "known" stream types. final byte[] array = getOrCreateBuffer(buffer.remaining()); @@ -171,6 +166,7 @@ final class ByteBufferWriter { return null; } } + private static long getChannelFieldOffset(Class<?> clazz) { try { if (clazz != null && UnsafeUtil.hasUnsafeArrayOperations()) { |