Provide readAllBytes(InputStream) helper to other modules

Author: mcculls

utils/src/main/java/datadog/instrument/glue/Glue.java

@@ -7,16 +7,14 @@
 package datadog.instrument.glue;
 
 import static java.nio.charset.StandardCharsets.UTF_16BE;
+import static java.util.Objects.requireNonNull;
 
 import datadog.instrument.utils.JVM;
-import java.io.ByteArrayOutputStream;
 import java.io.InputStream;
 import java.util.MissingResourceException;
-import java.util.Objects;
 
 /** Methods for loading instrumentation glue bytecode from string literals and resource files. */
 public final class Glue {
-
   private static final String GLUE_RESOURCE_PREFIX = "/datadog/instrument/glue/";
 
   private static final int BUFFER_SIZE = 8192;
@@ -41,22 +39,10 @@ public static byte[] unpackBytecode(String bytecode) {
    * @return the glue bytecode
    * @throws MissingResourceException if the bytecode cannot be read
    */
-  @SuppressWarnings({"Since15"})
   public static byte[] loadBytecode(Class<?> host, String glueName) {
     String glueResource = GLUE_RESOURCE_PREFIX + glueName;
-    try (InputStream is = Objects.requireNonNull(host.getResourceAsStream(glueResource))) {
-      if (JVM.atLeastJava(9)) {
-        return is.readAllBytes();
-      } else {
-        try (ByteArrayOutputStream os = new ByteArrayOutputStream()) {
-          int bytesRead;
-          byte[] buf = new byte[BUFFER_SIZE];
-          while ((bytesRead = is.read(buf, 0, BUFFER_SIZE)) != -1) {
-            os.write(buf, 0, bytesRead);
-          }
-          return os.toByteArray();
-        }
-      }
+    try (InputStream is = requireNonNull(host.getResourceAsStream(glueResource))) {
+      return JVM.readAllBytes(is);
     } catch (Throwable e) {
       String detail = "Cannot load " + glueResource + " from " + host + ": " + e;
       throw new MissingResourceException(detail, host.getName(), glueResource);

utils/src/main/java/datadog/instrument/utils/JVM.java

@@ -6,7 +6,11 @@
 
 package datadog.instrument.utils;
 
-/** Provides information about the JVM; used to select the best injection approach. */
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+/** Assorted JVM helpers; uses the best approach for the current JVM. */
 public final class JVM {
   private static final int JAVA_VERSION = getMajorJavaVersion();
 
@@ -53,4 +57,29 @@ private static int parseMajorJavaVersion(String str) {
     }
     return value;
   }
+
+  private static final int BUFFER_SIZE = 8192;
+
+  /**
+   * Reads all remaining bytes from the given input stream.
+   *
+   * @param is the input stream
+   * @return a byte array containing the bytes read from the input stream
+   * @throws IOException if an I/O error occurs
+   */
+  @SuppressWarnings("Since15")
+  public static byte[] readAllBytes(InputStream is) throws IOException {
+    if (JVM.atLeastJava(9)) {
+      return is.readAllBytes();
+    } else {
+      try (ByteArrayOutputStream os = new ByteArrayOutputStream()) {
+        int bytesRead;
+        byte[] buf = new byte[BUFFER_SIZE];
+        while ((bytesRead = is.read(buf, 0, BUFFER_SIZE)) != -1) {
+          os.write(buf, 0, bytesRead);
+        }
+        return os.toByteArray();
+      }
+    }
+  }
 }