garydgregory commented on code in PR #776:
URL: https://github.com/apache/commons-io/pull/776#discussion_r2328895181
##########
src/main/java/org/apache/commons/io/IOUtils.java:
##########
@@ -221,6 +221,21 @@ public class IOUtils {
*/
private static final char[] SCRATCH_CHAR_BUFFER_WO = charArray();
+ /**
+ * The maximum size of an array in many Java VMs.
+ */
+ private static final int MAX_ARRAY_LENGTH = Integer.MAX_VALUE - 8;
Review Comment:
Java 12's `ArraySupport` class calls this `SOFT_MAX_ARRAY_LENGTH`, so I
think we should use the same name.
##########
src/main/java/org/apache/commons/io/IOUtils.java:
##########
@@ -2637,57 +2652,65 @@ public static BufferedReader toBufferedReader(final
Reader reader, final int siz
}
/**
- * Gets the contents of an {@link InputStream} as a {@code byte[]}.
- * <p>
- * This method buffers the input internally, so there is no need to use a
{@link BufferedInputStream}.
- * </p>
+ * Reads all the bytes from an input stream in a byte array.
*
- * @param inputStream the {@link InputStream} to read.
- * @return the requested byte array.
- * @throws NullPointerException if the InputStream is {@code null}.
- * @throws IOException if an I/O error occurs or reading more
than {@link Integer#MAX_VALUE} occurs.
+ * <p>The memory used by this method is <strong>proportional</strong> to
the number
+ * of bytes read, which is only limited by {@link Integer#MAX_VALUE}. This
makes it unsuitable for
+ * processing large input streams, unless sufficient heap space is
available.</p>
+ *
+ * @param inputStream The {@link InputStream} to read; must not be {@code
null}.
+ * @return A new byte array.
+ * @throws IllegalArgumentException If the size of the stream is greater
than the maximum array size.
+ * @throws IOException If an I/O error occurs while reading.
+ * @throws NullPointerException If {@code inputStream} is {@code null}.
*/
public static byte[] toByteArray(final InputStream inputStream) throws
IOException {
- // We use a ThresholdingOutputStream to avoid reading AND writing more
than Integer.MAX_VALUE.
- try (UnsynchronizedByteArrayOutputStream ubaOutput =
UnsynchronizedByteArrayOutputStream.builder().get();
- ThresholdingOutputStream thresholdOutput = new
ThresholdingOutputStream(Integer.MAX_VALUE, os -> {
- throw new IllegalArgumentException(String.format("Cannot
read more than %,d into a byte array", Integer.MAX_VALUE));
- }, os -> ubaOutput)) {
- copy(inputStream, thresholdOutput);
- return ubaOutput.toByteArray();
+ final UnsynchronizedByteArrayOutputStream output =
+ copyToOutputStream(inputStream, MAX_ARRAY_LENGTH + 1,
DEFAULT_CHUNK_SIZE);
+ if (output.size() > MAX_ARRAY_LENGTH) {
+ throw new IllegalArgumentException(
+ String.format("Cannot read more than %,d into a byte
array", MAX_ARRAY_LENGTH));
}
+ return output.toByteArray();
}
/**
- * Gets the contents of an {@link InputStream} as a {@code byte[]}. Use
this method instead of
- * {@link #toByteArray(InputStream)} when {@link InputStream} size is
known.
+ * Reads exactly {@code size} bytes from the given {@link InputStream}
into a new {@code byte[]}.
*
- * @param input the {@link InputStream} to read.
- * @param size the size of {@link InputStream} to read, where 0 <
{@code size} <= length of input stream.
- * @return byte [] of length {@code size}.
- * @throws IOException if an I/O error occurs or {@link InputStream}
length is smaller than parameter {@code size}.
- * @throws IllegalArgumentException if {@code size} is less than zero.
+ * <p>The memory used by this method is <strong>proportional</strong> to
the number
+ * of bytes read and limited by the specified {@code size}. This makes it
suitable for
+ * processing large input streams, provided that
<strong>sufficient</strong> heap space is
+ * available.</p>
+ *
+ * @param input the {@link InputStream} to read; must not be {@code null}.
+ * @param size the exact number of bytes to read; must be {@code >= 0}.
+ * @return a new byte array of length {@code size}.
+ * @throws IllegalArgumentException if {@code size} is negative.
+ * @throws EOFException if the stream ends before {@code size}
bytes are read.
+ * @throws IOException if an I/O error occurs while reading.
+ * @throws NullPointerException if {@code input} is {@code null}.
* @since 2.1
*/
- @SuppressWarnings("resource")
public static byte[] toByteArray(final InputStream input, final int size)
throws IOException {
- return toByteArray(Objects.requireNonNull(input, "input")::read, size);
+ return toByteArray(input, size, DEFAULT_CHUNK_SIZE);
Review Comment:
Woa, this is surprising; now we are double-buffering and slowing down
existing call sites that don't want this new feature? It seems to like we
should _only_ do the double buffering when a call site chooses to use the new
API.
##########
src/main/java/org/apache/commons/io/IOUtils.java:
##########
@@ -221,6 +221,21 @@ public class IOUtils {
*/
private static final char[] SCRATCH_CHAR_BUFFER_WO = charArray();
+ /**
+ * The maximum size of an array in many Java VMs.
+ */
+ private static final int MAX_ARRAY_LENGTH = Integer.MAX_VALUE - 8;
+
+ /*
+ * Default maximum chunk size used when copying large streams into a byte
array.
+ * <p>
+ * This value is somewhat arbitrary, currently aligned with the value used
by
+ * <a
href="https://github.com/python/cpython/blob/3.14/Lib/_pyio.py";>Python</a>
Review Comment:
CPython is completely irrelevant here; it should not be mentioned, as we
certainly do not want to give the impression that we are aligning anything with
CPython. I also like to mention the value with `{@value}` in this kind of
Javadoc.
##########
src/main/java/org/apache/commons/io/IOUtils.java:
##########
@@ -2697,6 +2720,69 @@ public static byte[] toByteArray(final InputStream
input, final long size) throw
return toByteArray(input, (int) size);
}
+ /**
+ * Reads exactly {@code size} bytes from the given {@link InputStream}
into a new {@code byte[]}.
+ *
+ * <p>The memory used by this method is <strong>proportional</strong> to
the number
+ * of bytes read and limited by the specified {@code size}. This makes it
suitable for
+ * processing large input streams, provided that
<strong>sufficient</strong> heap space is
+ * available.</p>
+ *
+ * <p>This method processes the input stream in successive chunks of up to
+ * {@code chunkSize} bytes.</p>
+ *
+ * @param input the {@link InputStream} to read; must not be {@code
null}.
+ * @param size the exact number of bytes to read; must be {@code >=
0}.
+ * The actual bytes read are validated to equal {@code
size}.
+ * @param chunkSize The chunk size for incremental reading; must be
{@code > 0}.
+ * @return a new byte array of length {@code size}.
+ * @throws IllegalArgumentException if {@code size} is negative or {@code
chunkSize <= 0}.
+ * @throws EOFException if the stream ends before {@code size}
bytes are read.
+ * @throws IOException if an I/O error occurs while reading.
+ * @throws NullPointerException if {@code input} is {@code null}.
+ * @since 2.21.0
+ */
+ public static byte[] toByteArray(final InputStream input, final int size,
final int chunkSize) throws IOException {
+ Objects.requireNonNull(input, "input");
+ if (chunkSize <= 0) {
+ throw new IllegalArgumentException("Chunk size must be greater
than zero: " + chunkSize);
+ }
+ if (size <= chunkSize) {
+ // throws if size < 0
+ return toByteArray(input::read, size);
+ }
+ final UnsynchronizedByteArrayOutputStream output =
copyToOutputStream(input, size, chunkSize);
+ if (output.size() != size) {
+ throw new EOFException("Unexpected read size, current: " +
output.size() + ", expected: " + size);
+ }
+ return output.toByteArray();
+ }
+
+ /**
+ * Copies up to {@code size} bytes from the given {@link InputStream} into
a new {@link UnsynchronizedByteArrayOutputStream}.
+ *
Review Comment:
Could you remove extra line?
##########
src/main/java/org/apache/commons/io/IOUtils.java:
##########
@@ -2637,57 +2652,65 @@ public static BufferedReader toBufferedReader(final
Reader reader, final int siz
}
/**
- * Gets the contents of an {@link InputStream} as a {@code byte[]}.
- * <p>
- * This method buffers the input internally, so there is no need to use a
{@link BufferedInputStream}.
- * </p>
+ * Reads all the bytes from an input stream in a byte array.
*
- * @param inputStream the {@link InputStream} to read.
- * @return the requested byte array.
- * @throws NullPointerException if the InputStream is {@code null}.
- * @throws IOException if an I/O error occurs or reading more
than {@link Integer#MAX_VALUE} occurs.
+ * <p>The memory used by this method is <strong>proportional</strong> to
the number
+ * of bytes read, which is only limited by {@link Integer#MAX_VALUE}. This
makes it unsuitable for
+ * processing large input streams, unless sufficient heap space is
available.</p>
+ *
+ * @param inputStream The {@link InputStream} to read; must not be {@code
null}.
+ * @return A new byte array.
+ * @throws IllegalArgumentException If the size of the stream is greater
than the maximum array size.
+ * @throws IOException If an I/O error occurs while reading.
+ * @throws NullPointerException If {@code inputStream} is {@code null}.
*/
public static byte[] toByteArray(final InputStream inputStream) throws
IOException {
- // We use a ThresholdingOutputStream to avoid reading AND writing more
than Integer.MAX_VALUE.
- try (UnsynchronizedByteArrayOutputStream ubaOutput =
UnsynchronizedByteArrayOutputStream.builder().get();
- ThresholdingOutputStream thresholdOutput = new
ThresholdingOutputStream(Integer.MAX_VALUE, os -> {
- throw new IllegalArgumentException(String.format("Cannot
read more than %,d into a byte array", Integer.MAX_VALUE));
- }, os -> ubaOutput)) {
- copy(inputStream, thresholdOutput);
- return ubaOutput.toByteArray();
+ final UnsynchronizedByteArrayOutputStream output =
+ copyToOutputStream(inputStream, MAX_ARRAY_LENGTH + 1,
DEFAULT_CHUNK_SIZE);
Review Comment:
You can use line lengths up to 160 per our Checkstyle, so the code doesn't
end up reading like a newspaper 😉
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