diff --git a/spring-core/src/main/java/org/springframework/asm/ClassReader.java b/spring-core/src/main/java/org/springframework/asm/ClassReader.java index 62d00229f60..56b0d2ea3ae 100644 --- a/spring-core/src/main/java/org/springframework/asm/ClassReader.java +++ b/spring-core/src/main/java/org/springframework/asm/ClassReader.java @@ -88,6 +88,9 @@ public class ClassReader { */ static final int EXPAND_ASM_INSNS = 256; + /** The maximum size of array to allocate. */ + private static final int MAX_BUFFER_SIZE = 1024 * 1024; + /** The size of the temporary byte array used to read class input streams chunk by chunk. */ private static final int INPUT_STREAM_DATA_CHUNK_SIZE = 4096; @@ -310,13 +313,19 @@ public class ClassReader { if (inputStream == null) { throw new IOException("Class not found"); } + int bufferSize = calculateBufferSize(inputStream); try (ByteArrayOutputStream outputStream = new ByteArrayOutputStream()) { - byte[] data = new byte[INPUT_STREAM_DATA_CHUNK_SIZE]; + byte[] data = new byte[bufferSize]; int bytesRead; - while ((bytesRead = inputStream.read(data, 0, data.length)) != -1) { + int readCount = 0; + while ((bytesRead = inputStream.read(data, 0, bufferSize)) != -1) { outputStream.write(data, 0, bytesRead); + readCount++; } outputStream.flush(); + if (readCount == 1) { + return data; + } return outputStream.toByteArray(); } finally { if (close) { @@ -325,6 +334,20 @@ public class ClassReader { } } + private static int calculateBufferSize(final InputStream inputStream) throws IOException { + int expectedLength = inputStream.available(); + /* + * Some implementations can return 0 while holding available data + * (e.g. new FileInputStream("/proc/a_file")) + * Also in some pathological cases a very small number might be returned, + * and in this case we use default size + */ + if (expectedLength < 256) { + return INPUT_STREAM_DATA_CHUNK_SIZE; + } + return Math.min(expectedLength, MAX_BUFFER_SIZE); + } + // ----------------------------------------------------------------------------------------------- // Accessors // ----------------------------------------------------------------------------------------------- @@ -3456,7 +3479,6 @@ public class ClassReader { private int[] readBootstrapMethodsAttribute(final int maxStringLength) { char[] charBuffer = new char[maxStringLength]; int currentAttributeOffset = getFirstAttributeOffset(); - int[] currentBootstrapMethodOffsets = null; for (int i = readUnsignedShort(currentAttributeOffset - 2); i > 0; --i) { // Read the attribute_info's attribute_name and attribute_length fields. String attributeName = readUTF8(currentAttributeOffset, charBuffer); @@ -3464,17 +3486,17 @@ public class ClassReader { currentAttributeOffset += 6; if (Constants.BOOTSTRAP_METHODS.equals(attributeName)) { // Read the num_bootstrap_methods field and create an array of this size. - currentBootstrapMethodOffsets = new int[readUnsignedShort(currentAttributeOffset)]; + int[] result = new int[readUnsignedShort(currentAttributeOffset)]; // Compute and store the offset of each 'bootstrap_methods' array field entry. int currentBootstrapMethodOffset = currentAttributeOffset + 2; - for (int j = 0; j < currentBootstrapMethodOffsets.length; ++j) { - currentBootstrapMethodOffsets[j] = currentBootstrapMethodOffset; + for (int j = 0; j < result.length; ++j) { + result[j] = currentBootstrapMethodOffset; // Skip the bootstrap_method_ref and num_bootstrap_arguments fields (2 bytes each), // as well as the bootstrap_arguments array field (of size num_bootstrap_arguments * 2). currentBootstrapMethodOffset += 4 + readUnsignedShort(currentBootstrapMethodOffset + 2) * 2; } - return currentBootstrapMethodOffsets; + return result; } currentAttributeOffset += attributeLength; } diff --git a/spring-core/src/main/java/org/springframework/asm/ClassWriter.java b/spring-core/src/main/java/org/springframework/asm/ClassWriter.java index 8730027263b..de285663ee9 100644 --- a/spring-core/src/main/java/org/springframework/asm/ClassWriter.java +++ b/spring-core/src/main/java/org/springframework/asm/ClassWriter.java @@ -79,7 +79,7 @@ public class ClassWriter extends ClassVisitor { /** * The access_flags field of the JVMS ClassFile structure. This field can contain ASM specific - * access flags, such as {@link Opcodes#ACC_DEPRECATED} or {}@link Opcodes#ACC_RECORD}, which are + * access flags, such as {@link Opcodes#ACC_DEPRECATED} or {@link Opcodes#ACC_RECORD}, which are * removed when generating the ClassFile structure. */ private int accessFlags;