Upgrade to ASM master

Closes gh-27023

Author: jhoeller

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 @@ private static byte[] readStream(final InputStream inputStream, final boolean cl
     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 @@ private static byte[] readStream(final InputStream inputStream, final boolean cl
     }
   }
 
+  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
   // -----------------------------------------------------------------------------------------------
@@ -3456,25 +3479,24 @@ final int getFirstAttributeOffset() {
   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);
       int attributeLength = readInt(currentAttributeOffset + 2);
       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;
     }

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;