1 files changed, 520 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/skyframe/ValueOrExceptionUtils.java b/src/main/java/com/google/devtools/build/skyframe/ValueOrExceptionUtils.java
new file mode 100644
index 0000000000..e66f4faac0
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/skyframe/ValueOrExceptionUtils.java
@@ -0,0 +1,520 @@
+// Copyright 2014 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.google.devtools.build.skyframe;
+
+import javax.annotation.Nullable;
+
+/** Utilities for producing and consuming ValueOrException(2|3|4)? instances. */
+class ValueOrExceptionUtils {
+
+  /** The bottom exception type. */
+  class BottomException extends Exception {
+  }
+
+  @Nullable
+  public static SkyValue downcovert(ValueOrException<BottomException> voe) {
+    return voe.getValue();
+  }
+
+  public static <E1 extends Exception> ValueOrException<E1> downcovert(
+      ValueOrException2<E1, BottomException> voe, Class<E1> exceptionClass1) {
+    Exception e = voe.getException();
+    if (e == null) {
+      return new ValueOrExceptionValueImpl<>(voe.getValue());
+    }
+    // Here and below, we use type-safe casts for performance reasons. Another approach would be
+    // cascading try-catch-rethrow blocks, but that has a higher performance penalty.
+    if (exceptionClass1.isInstance(e)) {
+      return new ValueOrExceptionExnImpl<>(exceptionClass1.cast(e));
+    }
+    throw new IllegalStateException("shouldn't reach here " + e.getClass() + " " + exceptionClass1,
+        e);
+  }
+
+  public static <E1 extends Exception, E2 extends Exception> ValueOrException2<E1, E2> downconvert(
+      ValueOrException3<E1, E2, BottomException> voe, Class<E1> exceptionClass1,
+      Class<E2> exceptionClass2) {
+    Exception e = voe.getException();
+    if (e == null) {
+      return new ValueOrException2ValueImpl<>(voe.getValue());
+    }
+    if (exceptionClass1.isInstance(e)) {
+      return new ValueOrException2Exn1Impl<>(exceptionClass1.cast(e));
+    }
+    if (exceptionClass2.isInstance(e)) {
+      return new ValueOrException2Exn2Impl<>(exceptionClass2.cast(e));
+    }
+    throw new IllegalStateException("shouldn't reach here " + e.getClass() + " " + exceptionClass1
+        + " " + exceptionClass2, e);
+  }
+
+  public static <E1 extends Exception, E2 extends Exception, E3 extends Exception>
+      ValueOrException3<E1, E2, E3> downconvert(ValueOrException4<E1, E2, E3, BottomException> voe,
+          Class<E1> exceptionClass1, Class<E2> exceptionClass2, Class<E3> exceptionClass3) {
+    Exception e = voe.getException();
+    if (e == null) {
+      return new ValueOrException3ValueImpl<>(voe.getValue());
+    }
+    if (exceptionClass1.isInstance(e)) {
+      return new ValueOrException3Exn1Impl<>(exceptionClass1.cast(e));
+    }
+    if (exceptionClass2.isInstance(e)) {
+      return new ValueOrException3Exn2Impl<>(exceptionClass2.cast(e));
+    }
+    if (exceptionClass3.isInstance(e)) {
+      return new ValueOrException3Exn3Impl<>(exceptionClass3.cast(e));
+    }
+    throw new IllegalStateException("shouldn't reach here " + e.getClass() + " " + exceptionClass1
+        + " " + exceptionClass2 + " " + exceptionClass3, e);
+  }
+
+  public static <E extends Exception> ValueOrException<E> ofNull() {
+    return ValueOrExceptionValueImpl.ofNull();
+  }
+
+  public static ValueOrUntypedException ofValueUntyped(SkyValue value) {
+    return new ValueOrUntypedExceptionImpl(value);
+  }
+
+  public static <E extends Exception> ValueOrException<E> ofExn(E e) {
+    return new ValueOrExceptionExnImpl<>(e);
+  }
+
+  public static <E1 extends Exception, E2 extends Exception, E3 extends Exception,
+      E4 extends Exception> ValueOrException4<E1, E2, E3, E4> ofNullValue() {
+    return ValueOrException4ValueImpl.ofNullValue();
+  }
+
+  public static <E1 extends Exception, E2 extends Exception, E3 extends Exception,
+      E4 extends Exception> ValueOrException4<E1, E2, E3, E4> ofValue(SkyValue value) {
+    return new ValueOrException4ValueImpl<>(value);
+  }
+
+  public static <E1 extends Exception, E2 extends Exception, E3 extends Exception,
+      E4 extends Exception> ValueOrException4<E1, E2, E3, E4> ofExn1(E1 e) {
+    return new ValueOrException4Exn1Impl<>(e);
+  }
+
+  public static <E1 extends Exception, E2 extends Exception, E3 extends Exception,
+      E4 extends Exception> ValueOrException4<E1, E2, E3, E4> ofExn2(E2 e) {
+    return new ValueOrException4Exn2Impl<>(e);
+  }
+
+  public static <E1 extends Exception, E2 extends Exception, E3 extends Exception,
+      E4 extends Exception> ValueOrException4<E1, E2, E3, E4> ofExn3(E3 e) {
+    return new ValueOrException4Exn3Impl<>(e);
+  }
+
+  public static <E1 extends Exception, E2 extends Exception, E3 extends Exception,
+      E4 extends Exception> ValueOrException4<E1, E2, E3, E4> ofExn4(E4 e) {
+    return new ValueOrException4Exn4Impl<>(e);
+  }
+
+  private static class ValueOrUntypedExceptionImpl extends ValueOrUntypedException {
+    @Nullable
+    private final SkyValue value;
+
+    ValueOrUntypedExceptionImpl(@Nullable SkyValue value) {
+      this.value = value;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue getValue() {
+      return value;
+    }
+
+    @Override
+    public Exception getException() {
+      return null;
+    }
+  }
+
+  private static class ValueOrExceptionValueImpl<E extends Exception> extends ValueOrException<E> {
+    private static final ValueOrExceptionValueImpl<Exception> NULL =
+        new ValueOrExceptionValueImpl<Exception>((SkyValue) null);
+
+    @Nullable
+    private final SkyValue value;
+
+    private ValueOrExceptionValueImpl(@Nullable SkyValue value) {
+      this.value = value;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue get() {
+      return value;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue getValue() {
+      return value;
+    }
+
+    @Override
+    @Nullable
+    public Exception getException() {
+      return null;
+    }
+
+    @SuppressWarnings("unchecked")
+    public static <E extends Exception> ValueOrExceptionValueImpl<E> ofNull() {
+      return (ValueOrExceptionValueImpl<E>) NULL;
+    }
+  }
+
+  private static class ValueOrExceptionExnImpl<E extends Exception> extends ValueOrException<E> {
+    private final E e;
+
+    private ValueOrExceptionExnImpl(E e) {
+      this.e = e;
+    }
+
+    @Override
+    public SkyValue get() throws E {
+      throw e;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue getValue() {
+      return null;
+    }
+
+    @Override
+    public Exception getException() {
+      return e;
+    }
+  }
+
+  private static class ValueOrException2ValueImpl<E1 extends Exception, E2 extends Exception>
+      extends ValueOrException2<E1, E2> {
+    @Nullable
+    private final SkyValue value;
+
+    ValueOrException2ValueImpl(@Nullable SkyValue value) {
+      this.value = value;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue get() throws E1, E2 {
+      return value;
+    }
+
+    @Override
+    @Nullable
+    public Exception getException() {
+      return null;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue getValue() {
+      return value;
+    }
+  }
+
+  private static class ValueOrException2Exn1Impl<E1 extends Exception, E2 extends Exception>
+      extends ValueOrException2<E1, E2> {
+    private final E1 e;
+
+    private ValueOrException2Exn1Impl(E1 e) {
+      this.e = e;
+    }
+
+    @Override
+    public SkyValue get() throws E1 {
+      throw e;
+    }
+
+    @Override
+    public Exception getException() {
+      return e;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue getValue() {
+      return null;
+    }
+  }
+
+  private static class ValueOrException2Exn2Impl<E1 extends Exception, E2 extends Exception>
+      extends ValueOrException2<E1, E2> {
+    private final E2 e;
+
+    private ValueOrException2Exn2Impl(E2 e) {
+      this.e = e;
+    }
+
+    @Override
+    public SkyValue get() throws E2 {
+      throw e;
+    }
+
+    @Override
+    public Exception getException() {
+      return e;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue getValue() {
+      return null;
+    }
+  }
+
+  private static class ValueOrException3ValueImpl<E1 extends Exception, E2 extends Exception,
+      E3 extends Exception> extends ValueOrException3<E1, E2, E3> {
+    @Nullable
+    private final SkyValue value;
+
+    ValueOrException3ValueImpl(@Nullable SkyValue value) {
+      this.value = value;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue get() throws E1, E2 {
+      return value;
+    }
+
+    @Override
+    @Nullable
+    public Exception getException() {
+      return null;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue getValue() {
+      return value;
+    }
+  }
+
+  private static class ValueOrException3Exn1Impl<E1 extends Exception, E2 extends Exception,
+      E3 extends Exception> extends ValueOrException3<E1, E2, E3> {
+    private final E1 e;
+
+    private ValueOrException3Exn1Impl(E1 e) {
+      this.e = e;
+    }
+
+    @Override
+    public SkyValue get() throws E1 {
+      throw e;
+    }
+
+    @Override
+    public Exception getException() {
+      return e;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue getValue() {
+      return null;
+    }
+  }
+
+  private static class ValueOrException3Exn2Impl<E1 extends Exception, E2 extends Exception,
+      E3 extends Exception> extends ValueOrException3<E1, E2, E3> {
+    private final E2 e;
+
+    private ValueOrException3Exn2Impl(E2 e) {
+      this.e = e;
+    }
+
+    @Override
+    public SkyValue get() throws E2 {
+      throw e;
+    }
+
+    @Override
+    public Exception getException() {
+      return e;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue getValue() {
+      return null;
+    }
+  }
+
+  private static class ValueOrException3Exn3Impl<E1 extends Exception, E2 extends Exception,
+      E3 extends Exception> extends ValueOrException3<E1, E2, E3> {
+    private final E3 e;
+
+    private ValueOrException3Exn3Impl(E3 e) {
+      this.e = e;
+    }
+
+    @Override
+    public SkyValue get() throws E3 {
+      throw e;
+    }
+
+    @Override
+    public Exception getException() {
+      return e;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue getValue() {
+      return null;
+    }
+  }
+
+  private static class ValueOrException4ValueImpl<E1 extends Exception, E2 extends Exception,
+      E3 extends Exception, E4 extends Exception> extends ValueOrException4<E1, E2, E3, E4> {
+    private static final ValueOrException4ValueImpl<Exception, Exception, Exception,
+        Exception> NULL = new ValueOrException4ValueImpl<>((SkyValue) null);
+
+    @Nullable
+    private final SkyValue value;
+
+    ValueOrException4ValueImpl(@Nullable SkyValue value) {
+      this.value = value;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue get() throws E1, E2 {
+      return value;
+    }
+
+    @Override
+    @Nullable
+    public Exception getException() {
+      return null;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue getValue() {
+      return value;
+    }
+
+    @SuppressWarnings("unchecked")
+    private static <E1 extends Exception, E2 extends Exception, E3 extends Exception,
+        E4 extends Exception>ValueOrException4ValueImpl<E1, E2, E3, E4> ofNullValue() {
+      return (ValueOrException4ValueImpl<E1, E2, E3, E4>) NULL;
+    }
+  }
+
+  private static class ValueOrException4Exn1Impl<E1 extends Exception, E2 extends Exception,
+      E3 extends Exception, E4 extends Exception> extends ValueOrException4<E1, E2, E3, E4> {
+    private final E1 e;
+
+    private ValueOrException4Exn1Impl(E1 e) {
+      this.e = e;
+    }
+
+    @Override
+    public SkyValue get() throws E1 {
+      throw e;
+    }
+
+    @Override
+    public Exception getException() {
+      return e;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue getValue() {
+      return null;
+    }
+  }
+
+  private static class ValueOrException4Exn2Impl<E1 extends Exception, E2 extends Exception,
+      E3 extends Exception, E4 extends Exception> extends ValueOrException4<E1, E2, E3, E4> {
+    private final E2 e;
+
+    private ValueOrException4Exn2Impl(E2 e) {
+      this.e = e;
+    }
+
+    @Override
+    public SkyValue get() throws E2 {
+      throw e;
+    }
+
+    @Override
+    public Exception getException() {
+      return e;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue getValue() {
+      return null;
+    }
+  }
+
+  private static class ValueOrException4Exn3Impl<E1 extends Exception, E2 extends Exception,
+      E3 extends Exception, E4 extends Exception> extends ValueOrException4<E1, E2, E3, E4> {
+    private final E3 e;
+
+    private ValueOrException4Exn3Impl(E3 e) {
+      this.e = e;
+    }
+
+    @Override
+    public SkyValue get() throws E3 {
+      throw e;
+    }
+
+    @Override
+    public Exception getException() {
+      return e;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue getValue() {
+      return null;
+    }
+  }
+
+  private static class ValueOrException4Exn4Impl<E1 extends Exception, E2 extends Exception,
+      E3 extends Exception, E4 extends Exception> extends ValueOrException4<E1, E2, E3, E4> {
+    private final E4 e;
+
+    private ValueOrException4Exn4Impl(E4 e) {
+      this.e = e;
+    }
+
+    @Override
+    public SkyValue get() throws E4 {
+      throw e;
+    }
+
+    @Override
+    public Exception getException() {
+      return e;
+    }
+
+    @Override
+    @Nullable
+    public SkyValue getValue() {
+      return null;
+    }
+  }
+}