This is an automated email from the ASF dual-hosted git repository.
desruisseaux pushed a commit to branch geoapi-4.0
in repository https://gitbox.apache.org/repos/asf/sis.git
commit f96f7ad0f81b69506c16b18c44730fb238fd57a8
Author: Martin Desruisseaux <martin.desruisse...@geomatys.com>
AuthorDate: Thu Feb 9 14:55:16 2023 +0100
When the `InputStream` to wrap in a `ChannelDataInput` is backed by an
array,
wrap the underlying array (in read-only mode) instead of copying it.
---
.../sis/internal/sql/postgis/RasterReader.java | 14 ++-
.../sis/internal/storage/io/ChannelDataInput.java | 27 +++--
.../storage/io/InputStreamArrayGetter.java | 135 +++++++++++++++++++++
.../storage/io/InputStreamArrayGetterTest.java | 62 ++++++++++
.../apache/sis/test/suite/StorageTestSuite.java | 1 +
5 files changed, 221 insertions(+), 18 deletions(-)
diff --git
a/storage/sis-sqlstore/src/main/java/org/apache/sis/internal/sql/postgis/RasterReader.java
b/storage/sis-sqlstore/src/main/java/org/apache/sis/internal/sql/postgis/RasterReader.java
index 8b056cbc5a..70c5633727 100644
---
a/storage/sis-sqlstore/src/main/java/org/apache/sis/internal/sql/postgis/RasterReader.java
+++
b/storage/sis-sqlstore/src/main/java/org/apache/sis/internal/sql/postgis/RasterReader.java
@@ -37,7 +37,6 @@ import java.awt.image.DataBufferDouble;
import java.awt.image.WritableRaster;
import java.awt.image.BufferedImage;
import java.awt.image.RasterFormatException;
-import java.nio.channels.Channels;
import org.opengis.referencing.crs.CoordinateReferenceSystem;
import org.apache.sis.coverage.SampleDimension;
import org.apache.sis.coverage.grid.GridCoverage;
@@ -46,6 +45,7 @@ import org.apache.sis.coverage.grid.GridExtent;
import org.apache.sis.coverage.grid.GridGeometry;
import org.apache.sis.internal.coverage.j2d.ColorModelFactory;
import org.apache.sis.internal.referencing.j2d.AffineTransform2D;
+import org.apache.sis.internal.storage.io.InputStreamArrayGetter;
import org.apache.sis.internal.storage.io.ChannelDataInput;
import org.apache.sis.internal.sql.feature.InfoStatements;
import org.apache.sis.internal.util.Constants;
@@ -70,7 +70,7 @@ import static
org.apache.sis.internal.sql.postgis.Band.OPPOSITE_SIGN;
*
* @author Johann Sorel (Geomatys)
* @author Martin Desruisseaux (Geomatys)
- * @version 1.2
+ * @version 1.4
* @since 1.2
*/
public final class RasterReader extends RasterFormat {
@@ -398,9 +398,11 @@ public final class RasterReader extends RasterFormat {
* @throws IOException if an error occurred while reading data from the
input stream.
*/
public ChannelDataInput channel(final InputStream input) throws
IOException {
- if (buffer == null) {
- buffer = ByteBuffer.allocate(8192);
- }
- return new ChannelDataInput("raster", Channels.newChannel(input),
buffer, false);
+ return InputStreamArrayGetter.channel("raster", input, () -> {
+ if (buffer == null) {
+ buffer = ByteBuffer.allocate(8192);
+ }
+ return buffer;
+ });
}
}
diff --git
a/storage/sis-storage/src/main/java/org/apache/sis/internal/storage/io/ChannelDataInput.java
b/storage/sis-storage/src/main/java/org/apache/sis/internal/storage/io/ChannelDataInput.java
index 40eb30dbe9..ec18853ec8 100644
---
a/storage/sis-storage/src/main/java/org/apache/sis/internal/storage/io/ChannelDataInput.java
+++
b/storage/sis-storage/src/main/java/org/apache/sis/internal/storage/io/ChannelDataInput.java
@@ -86,6 +86,9 @@ public class ChannelDataInput extends ChannelData {
* If the buffer already contains some data, then the {@code filled}
argument shall be {@code true}.
* Otherwise (e.g. if it is a newly created buffer), then {@code filled}
shall be {@code false}.
*
+ * <p><b>Tip:</b>
+ * for building a data input from an input stream, see {@link
InputStreamArrayGetter}.</p>
+ *
* @param filename a short identifier (typically a filename without
path) used for formatting error message.
* @param channel the channel from where data are read.
* @param buffer the buffer where to copy the data.
@@ -105,18 +108,6 @@ public class ChannelDataInput extends ChannelData {
}
}
- /**
- * Creates a new input stream from the given {@code ChannelDataInput}.
- * This constructor is invoked when we need to change the implementation
class.
- * The old input should not be used anymore after this constructor has
been invoked.
- *
- * @param input the existing instance from which to takes the channel
and buffer.
- */
- ChannelDataInput(final ChannelDataInput input) {
- super(input);
- channel = input.channel;
- }
-
/**
* Creates a new instance for a buffer filled with the bytes to use.
* This constructor uses an independent, read-only view of the given
buffer.
@@ -130,6 +121,18 @@ public class ChannelDataInput extends ChannelData {
channel = new NullChannel();
}
+ /**
+ * Creates a new input stream from the given {@code ChannelDataInput}.
+ * This constructor is invoked when we need to change the implementation
class.
+ * The old input should not be used anymore after this constructor has
been invoked.
+ *
+ * @param input the existing instance from which to takes the channel
and buffer.
+ */
+ ChannelDataInput(final ChannelDataInput input) {
+ super(input);
+ channel = input.channel;
+ }
+
/**
* Returns the length of the stream (in bytes), or -1 if unknown.
* The length is relative to the channel position at {@linkplain
#ChannelDataInput construction time}.
diff --git
a/storage/sis-storage/src/main/java/org/apache/sis/internal/storage/io/InputStreamArrayGetter.java
b/storage/sis-storage/src/main/java/org/apache/sis/internal/storage/io/InputStreamArrayGetter.java
new file mode 100644
index 0000000000..7432a391a7
--- /dev/null
+++
b/storage/sis-storage/src/main/java/org/apache/sis/internal/storage/io/InputStreamArrayGetter.java
@@ -0,0 +1,135 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.sis.internal.storage.io;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.ByteArrayInputStream;
+import java.nio.ByteBuffer;
+import java.nio.channels.Channels;
+import java.nio.channels.ReadableByteChannel;
+import java.util.function.Supplier;
+import org.apache.sis.util.logging.Logging;
+import org.apache.sis.internal.storage.StoreUtilities;
+
+
+/**
+ * A hack for getting the backing array of an input stream if that array
exists.
+ * This class searches the array in the following locations:
+ *
+ * <ul>
+ * <li>{@link ByteArrayInputStream#buf} together with offset and length.
+ * Those fields have {@code protected} access, so they are committed
Java API.
+ * However as of Java 19, there is no public accessor for them.</li>
+ * </ul>
+ *
+ * @author Martin Desruisseaux (Geomatys)
+ * @version 1.4
+ * @since 1.4
+ */
+public final class InputStreamArrayGetter extends OutputStream {
+ /**
+ * The buffer wrapping the array, or {@code null} if unknown.
+ * This buffer is not read-only, but nevertheless should not be modified.
+ */
+ private ByteBuffer buffer;
+
+ /**
+ * Creates a pseudo output stream to use as a trick for getting the
backing array.
+ */
+ private InputStreamArrayGetter() {
+ }
+
+ /**
+ * Whether it is hopefully safe to apply the trick used by this class for
getting the backing array.
+ * The trick is that the {@link
ByteArrayInputStream#transferTo(OutputStream)} implementation gives
+ * the backing array in argument in a call to {@link
InputStream#write(byte[], int, int)} method.
+ * This is verified by looking at the OpenJDK source code, and presumed
relatively stable because
+ * the code uses only protected fields and public methods, which are
committed API.
+ * But because users could override the {@code transferTo(…)} method in a
subclass,
+ * we rely on this strick only if the method implementation is the one
provided by
+ * the standard {@link ByteArrayInputStream} class.
+ *
+ * @param input the input stream for which to verify the implementation
class.
+ * @return whether the implementation is the OpenJDK one.
+ */
+ private static boolean isKnownImplementation(final InputStream input) {
+ try {
+ return input.getClass().getMethod("transferTo",
OutputStream.class).getDeclaringClass() == ByteArrayInputStream.class;
+ } catch (NoSuchMethodException e) {
+ // Should not happen because we requested a method which should
exist.
+ Logging.unexpectedException(StoreUtilities.LOGGER,
InputStreamArrayGetter.class, "isKnownImplementation", e);
+ return false;
+ }
+ }
+
+ /**
+ * Creates a new data input for the given input stream.
+ * If the input stream is backed by an array, the array will be wrapped in
a read-only mode.
+ *
+ * @param filename a short identifier (typically a filename without
path) used for formatting error message.
+ * @param input the input stream from where data are read.
+ * @param bs supplier of the buffer where to copy the data.
+ * @return the data input using a readable channel.
+ * @throws IOException if an error occurred while reading the input stream.
+ */
+ public static ChannelDataInput channel(final String filename, final
InputStream input, final Supplier<ByteBuffer> bs)
+ throws IOException
+ {
+ if (isKnownImplementation(input)) {
+ final InputStreamArrayGetter getter = new InputStreamArrayGetter();
+ input.transferTo(getter);
+ if (getter.buffer != null) {
+ return new ChannelDataInput(filename, getter.buffer);
+ }
+ }
+ final ReadableByteChannel channel = Channels.newChannel(input);
+ return new ChannelDataInput(filename, channel, bs.get(), false);
+ }
+
+ /**
+ * Invoked by {@link ByteArrayInputStream#transferTo(OutputStream)}.
+ * We use this method as a callback for getting the underlying array.
+ *
+ * @param array the data.
+ * @param offset the start offset in the array.
+ * @param length the number of valid bytes in the array.
+ * @throws IOException if this method is invoked more than once.
+ */
+ @Override
+ public void write(final byte[] array, final int offset, final int length)
throws IOException {
+ if (buffer == null) {
+ buffer = ByteBuffer.wrap(array, offset, length);
+ } else {
+ super.write(array, offset, length);
+ }
+ }
+
+ /**
+ * Should never be invoked. If this method is nevertheless invoked,
+ * then the {@link ByteArrayInputStream#transferTo(OutputStream)}
+ * implementation is not what we expected.
+ *
+ * @param b ignored.
+ * @throws IOException always thrown.
+ */
+ @Override
+ public void write(int b) throws IOException {
+ throw new IOException("Unexpected implementation.");
+ }
+}
diff --git
a/storage/sis-storage/src/test/java/org/apache/sis/internal/storage/io/InputStreamArrayGetterTest.java
b/storage/sis-storage/src/test/java/org/apache/sis/internal/storage/io/InputStreamArrayGetterTest.java
new file mode 100644
index 0000000000..ae4ea03579
--- /dev/null
+++
b/storage/sis-storage/src/test/java/org/apache/sis/internal/storage/io/InputStreamArrayGetterTest.java
@@ -0,0 +1,62 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.sis.internal.storage.io;
+
+import java.io.IOException;
+import java.io.ByteArrayInputStream;
+import org.apache.sis.test.TestCase;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+
+/**
+ * Tests the {@link InputStreamArrayGetter} class.
+ *
+ * @author Martin Desruisseaux (Geomatys)
+ * @version 1.4
+ * @since 1.4
+ */
+public final class InputStreamArrayGetterTest extends TestCase {
+ /**
+ * Tests the creation of a channel data input which uses directly the
array.
+ *
+ * @throws IOException if an error occurred while creating the channel
data input.
+ */
+ @Test
+ public void testDirectChannel() throws IOException {
+ final var array = new byte[20];
+ for (int i=0; i<array.length; i++) {
+ array[i] = (byte) ((i ^ 5772) * 37);
+ }
+ final int offset = 7;
+ final var input = new ByteArrayInputStream(array, offset, 9);
+ final ChannelDataInput data = InputStreamArrayGetter.channel("Test",
input, () -> {
+ throw new AssertionError("Should not create new buffer.");
+ });
+ /*
+ * Replace a few values in the backing array AFTER the
`ChannelDataInput` creation.
+ * If the data input does not wrap the array, the changes below would
be unnoticed.
+ */
+ array[offset + 1] = 99; // Replace 20.
+ array[offset + 4] = 100; // Replace -125.
+ final byte[] expected = {23, 99, 57, 94, 100, -128};
+ for (int i=0; i<expected.length; i++) {
+ assertEquals(expected[i], data.readByte());
+ }
+ }
+}
diff --git
a/storage/sis-storage/src/test/java/org/apache/sis/test/suite/StorageTestSuite.java
b/storage/sis-storage/src/test/java/org/apache/sis/test/suite/StorageTestSuite.java
index 8a8556ede6..e84a691f07 100644
---
a/storage/sis-storage/src/test/java/org/apache/sis/test/suite/StorageTestSuite.java
+++
b/storage/sis-storage/src/test/java/org/apache/sis/test/suite/StorageTestSuite.java
@@ -40,6 +40,7 @@ import org.junit.BeforeClass;
org.apache.sis.internal.storage.io.HyperRectangleReaderTest.class,
org.apache.sis.internal.storage.io.RewindableLineReaderTest.class,
org.apache.sis.internal.storage.io.FileCacheByteChannelTest.class,
+ org.apache.sis.internal.storage.io.InputStreamArrayGetterTest.class,
org.apache.sis.internal.storage.MetadataBuilderTest.class,
org.apache.sis.internal.storage.RangeArgumentTest.class,
org.apache.sis.internal.storage.MemoryGridResourceTest.class,
