Merge "Improve DataSource interface." (ce4c9d71) · Commits · e / os / android_build

tools/apksigner/core/src/com/android/apksigner/core/internal/util/ByteBufferDataSource.java

+53 −21

Original line number	Diff line number	Diff line
		@@ -28,7 +28,7 @@ import java.nio.ByteBuffer;
		public class ByteBufferDataSource implements DataSource {

		private final ByteBuffer mBuffer;
		private final long mSize;
		private final int mSize;

		/**
		* Constructs a new {@code ByteBufferDigestSource} based on the data contained in the provided
		@@ -45,29 +45,39 @@ public class ByteBufferDataSource implements DataSource {
		}

		@Override
		public void feed(long offset, int size, DataSink sink) throws IOException {
		if (offset < 0) {
		throw new IllegalArgumentException("offset: " + offset);
		public ByteBufferDataSource slice(long offset, long size) {
		if ((offset == 0) && (size == mSize)) {
		return this;
		}
		if (size < 0) {
		throw new IllegalArgumentException("size: " + size);
		}
		if (offset > mSize) {
		throw new IllegalArgumentException(
		"offset (" + offset + ") > source size (" + mSize + ")");
		}
		long endOffset = offset + size;
		if (endOffset < offset) {
		throw new IllegalArgumentException(
		"offset (" + offset + ") + size (" + size + ") overflow");
		checkChunkValid(offset, size);

		// checkChunkValid ensures that it's OK to cast offset and size to int.
		int chunkPosition = (int) offset;
		int chunkLimit = (int) (chunkPosition + size);
		// Creating a slice of ByteBuffer modifies the state of the source ByteBuffer (position
		// and limit fields, to be more specific). We thus use synchronization around these
		// state-changing operations to make instances of this class thread-safe.
		synchronized (mBuffer) {
		// ByteBuffer.limit(int) and .position(int) check that that the position >= limit
		// invariant is not broken. Thus, the only way to safely change position and limit
		// without caring about their current values is to first set position to 0 or set the
		// limit to capacity.
		mBuffer.position(0);

		mBuffer.limit(chunkLimit);
		mBuffer.position(chunkPosition);
		// Create a ByteBufferDataSource for the slice of the buffer between limit and position.
		return new ByteBufferDataSource(mBuffer);
		}
		if (endOffset > mSize) {
		throw new IllegalArgumentException(
		"offset (" + offset + ") + size (" + size + ") > source size (" + mSize +")");
		}

		int chunkPosition = (int) offset; // safe to downcast because mSize <= Integer.MAX_VALUE
		int chunkLimit = (int) endOffset; // safe to downcast because mSize <= Integer.MAX_VALUE
		@Override
		public void feed(long offset, long size, DataSink sink) throws IOException {
		checkChunkValid(offset, size);

		// checkChunkValid ensures that it's OK to cast offset and size to int.
		int chunkPosition = (int) offset;
		int chunkLimit = (int) (chunkPosition + size);
		ByteBuffer chunk;
		// Creating a slice of ByteBuffer modifies the state of the source ByteBuffer (position
		// and limit fields, to be more specific). We thus use synchronization around these
		@@ -86,4 +96,26 @@ public class ByteBufferDataSource implements DataSource {

		sink.consume(chunk);
		}

		private void checkChunkValid(long offset, long size) {
		if (offset < 0) {
		throw new IllegalArgumentException("offset: " + offset);
		}
		if (size < 0) {
		throw new IllegalArgumentException("size: " + size);
		}
		if (offset > mSize) {
		throw new IllegalArgumentException(
		"offset (" + offset + ") > source size (" + mSize + ")");
		}
		long endOffset = offset + size;
		if (endOffset < offset) {
		throw new IllegalArgumentException(
		"offset (" + offset + ") + size (" + size + ") overflow");
		}
		if (endOffset > mSize) {
		throw new IllegalArgumentException(
		"offset (" + offset + ") + size (" + size + ") > source size (" + mSize +")");
		}
		}
		}

tools/apksigner/core/src/com/android/apksigner/core/util/DataSource.java

+7 −1

Original line number	Diff line number	Diff line
		@@ -43,5 +43,11 @@ public interface DataSource {
		* @param offset index (in bytes) at which the chunk starts inside data source
		* @param size size (in bytes) of the chunk
		*/
		void feed(long offset, int size, DataSink sink) throws IOException;
		void feed(long offset, long size, DataSink sink) throws IOException;

		/**
		* Returns a data source representing the specified region of data of this data source. Changes
		* to data represented by this data source will also be visible in the returned data source.
		*/
		DataSource slice(long offset, long size);
		}

tools/apksigner/core/src/com/android/apksigner/core/util/DataSources.java

+2 −1

Original line number	Diff line number	Diff line
		@@ -12,7 +12,8 @@ public abstract class DataSources {

		/**
		* Returns a {@link DataSource} backed by the provided {@link ByteBuffer}. The data source
		* represents the data contained between the position and limit of the buffer.
		* represents the data contained between the position and limit of the buffer. Changes to the
		* buffer's contents will be visible in the data source.
		*/
		public static DataSource asDataSource(ByteBuffer buffer) {
		if (buffer == null) {