HMember: flatten array into fields to reduce memory footprint

java/java-analysis-impl/src/com/intellij/codeInspection/bytecodeAnalysis/BytecodeAnalysisIndex.java

@@ -150,7 +150,7 @@ public class BytecodeAnalysisIndex extends ScalarIndexExtension<HMember> {
 
     @Override
     public void save(@NotNull DataOutput out, HMember value) throws IOException {
-      out.write(value.myBytes);
+      out.write(value.asBytes());
     }
 
     @Override
@@ -279,7 +279,7 @@ public class BytecodeAnalysisIndex extends ScalarIndexExtension<HMember> {
     }
 
     private static void writeKey(@NotNull DataOutput out, EKey key, MessageDigest md) throws IOException {
-      out.write(key.member.hashed(md).myBytes);
+      out.write(key.member.hashed(md).asBytes());
       int rawDirKey = key.negated ? -key.dirKey : key.dirKey;
       DataInputOutputUtil.writeINT(out, rawDirKey);
       out.writeBoolean(key.stable);

java/java-analysis-impl/src/com/intellij/codeInspection/bytecodeAnalysis/HMember.java

@@ -19,8 +19,8 @@ import com.intellij.openapi.vfs.CharsetToolkit;
 import one.util.streamex.IntStreamEx;
 import org.jetbrains.annotations.NotNull;
 
+import java.nio.ByteBuffer;
 import java.security.MessageDigest;
-import java.util.Arrays;
 
 import static com.intellij.codeInspection.bytecodeAnalysis.BytecodeAnalysisConverter.getMessageDigest;
 
@@ -29,41 +29,60 @@ import static com.intellij.codeInspection.bytecodeAnalysis.BytecodeAnalysisConve
  */
 public final class HMember implements MemberDescriptor {
   // how many bytes are taken from class fqn digest
-  private static final int CLASS_HASH_SIZE = 10;
+  private static final int CLASS_HASH_SIZE = Long.BYTES+Short.BYTES;
   // how many bytes are taken from signature digest
-  private static final int SIGNATURE_HASH_SIZE = 4;
+  private static final int SIGNATURE_HASH_SIZE = Integer.BYTES;
   static final int HASH_SIZE = CLASS_HASH_SIZE + SIGNATURE_HASH_SIZE;
 
-  @NotNull
-  final byte[] myBytes;
+  final long myClassHi;
+  final short myClassLo;
+  final int myMethod;
 
   HMember(Member method, MessageDigest md) {
     if (md == null) {
       md = getMessageDigest();
     }
     byte[] classDigest = md.digest(method.internalClassName.getBytes(CharsetToolkit.UTF8_CHARSET));
+    ByteBuffer classBuffer = ByteBuffer.wrap(classDigest);
+    myClassHi = classBuffer.getLong();
+    myClassLo = classBuffer.getShort();
+
     md.update(method.methodName.getBytes(CharsetToolkit.UTF8_CHARSET));
     md.update(method.methodDesc.getBytes(CharsetToolkit.UTF8_CHARSET));
     byte[] sigDigest = md.digest();
-    myBytes = new byte[HASH_SIZE];
-    System.arraycopy(classDigest, 0, myBytes, 0, CLASS_HASH_SIZE);
-    System.arraycopy(sigDigest, 0, myBytes, CLASS_HASH_SIZE, SIGNATURE_HASH_SIZE);
+    myMethod = ByteBuffer.wrap(sigDigest).getInt();
   }
 
   public HMember(@NotNull byte[] bytes) {
-    myBytes = bytes;
+    ByteBuffer buffer = ByteBuffer.wrap(bytes);
+    myClassHi = buffer.getLong();
+    myClassLo = buffer.getShort();
+    myMethod = buffer.getInt();
+  }
+
+  @NotNull
+  byte[] asBytes() {
+    ByteBuffer bytes = ByteBuffer.allocate(HASH_SIZE);
+    bytes.putLong(myClassHi).putShort(myClassLo).putInt(myMethod);
+    return bytes.array();
   }
 
   @Override
   public boolean equals(Object o) {
     if (this == o) return true;
     if (o == null || getClass() != o.getClass()) return false;
-    return Arrays.equals(myBytes, ((HMember)o).myBytes);
+    HMember that = (HMember)o;
+    return that.myClassHi == myClassHi && that.myClassLo == myClassLo && that.myMethod == myMethod;
   }
 
   @Override
   public int hashCode() {
-    return Arrays.hashCode(myBytes);
+    // Must work as Arrays.hashCode(asBytes()) to preserve compatibility with old caches
+    int result = 1;
+    for (int i = Long.BYTES - 1; i >= 0; i--) result = result * 31 + (byte)((myClassHi >>> (i * 8)) & 0xFF);
+    for (int i = Short.BYTES - 1; i >= 0; i--) result = result * 31 + (byte)((myClassLo >>> (i * 8)) & 0xFF);
+    for (int i = Integer.BYTES - 1; i >= 0; i--) result = result * 31 + (byte)((myMethod >>> (i * 8)) & 0xFF);
+    return result;
   }
 
   @NotNull
@@ -73,7 +92,7 @@ public final class HMember implements MemberDescriptor {
   }
 
   public String toString() {
-    return bytesToString(myBytes);
+    return bytesToString(asBytes());
   }
 
   static String bytesToString(byte[] key) {