Introduce CelValue. Implement CelValues for primitive types.

PiperOrigin-RevId: 576690957

common/src/main/java/dev/cel/common/values/BUILD.bazel

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+package(
+    default_applicable_licenses = [
+        "//:license",
+    ],
+    default_visibility = [
+        "//common/values:__pkg__",
+    ],
+)
+
+# keep sorted
+CEL_VALUES_SOURCES = [
+    "BoolValue.java",
+    "BytesValue.java",
+    "DoubleValue.java",
+    "DurationValue.java",
+    "EnumValue.java",
+    "IntValue.java",
+    "NullValue.java",
+    "StringValue.java",
+    "TimestampValue.java",
+    "UintValue.java",
+]
+
+java_library(
+    name = "cel_value",
+    srcs = ["CelValue.java"],
+    tags = [
+    ],
+    deps = [
+        "//common/annotations",
+        "@maven//:com_google_errorprone_error_prone_annotations",
+    ],
+)
+
+java_library(
+    name = "values",
+    srcs = CEL_VALUES_SOURCES,
+    tags = [
+    ],
+    deps = [
+        ":cel_byte_string",
+        ":cel_value",
+        "//:auto_value",
+        "@maven//:com_google_errorprone_error_prone_annotations",
+        "@maven//:com_google_guava_guava",
+    ],
+)
+
+java_library(
+    name = "cel_byte_string",
+    srcs = ["CelByteString.java"],
+    tags = [
+    ],
+    deps = [
+        "@maven//:com_google_errorprone_error_prone_annotations",
+        "@maven//:com_google_guava_guava",
+    ],
+)

common/src/main/java/dev/cel/common/values/BoolValue.java

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+// Copyright 2023 Google LLC
+//
+// 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
+//
+//      https://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 dev.cel.common.values;
+
+import com.google.auto.value.AutoValue;
+import com.google.errorprone.annotations.Immutable;
+
+/** BoolValue is a simple CelValue wrapper around Java booleans. */
+@AutoValue
+@Immutable
+public abstract class BoolValue extends CelValue {
+
+  @Override
+  public abstract Boolean value();
+
+  @Override
+  public boolean isZeroValue() {
+    return !value();
+  }
+
+  public static BoolValue create(Boolean value) {
+    return new AutoValue_BoolValue(value);
+  }
+}

common/src/main/java/dev/cel/common/values/BytesValue.java

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+// Copyright 2023 Google LLC
+//
+// 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
+//
+//      https://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 dev.cel.common.values;
+
+import com.google.auto.value.AutoValue;
+import com.google.errorprone.annotations.Immutable;
+
+/** BytesValue is a simple CelValue wrapper around CelByteString (immutable byte string). */
+@AutoValue
+@Immutable
+public abstract class BytesValue extends CelValue {
+
+  @Override
+  public abstract CelByteString value();
+
+  @Override
+  public boolean isZeroValue() {
+    return value().isEmpty();
+  }
+
+  public static BytesValue create(CelByteString value) {
+    return new AutoValue_BytesValue(value);
+  }
+}

common/src/main/java/dev/cel/common/values/CelByteString.java

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+// Copyright 2023 Google LLC
+//
+// 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
+//
+//      https://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 dev.cel.common.values;
+
+import com.google.common.base.Preconditions;
+import com.google.errorprone.annotations.Immutable;
+import java.util.Arrays;
+
+/** CelByteString is an immutable sequence of a byte array. */
+@Immutable
+@SuppressWarnings("Immutable") // We make defensive copies on the byte array.
+public final class CelByteString {
+  private static final byte[] EMPTY_BYTE_ARRAY = new byte[0];
+  public static final CelByteString EMPTY = new CelByteString(EMPTY_BYTE_ARRAY);
+
+  private final byte[] data;
+
+  private volatile int hash = 0;
+
+  public static CelByteString of(byte[] buffer) {
+    Preconditions.checkNotNull(buffer);
+    if (buffer.length == 0) {
+      return EMPTY;
+    }
+    return new CelByteString(buffer);
+  }
+
+  public int size() {
+    return data.length;
+  }
+
+  public boolean isEmpty() {
+    return data.length == 0;
+  }
+
+  public byte[] toByteArray() {
+    int size = size();
+    if (size == 0) {
+      return EMPTY_BYTE_ARRAY;
+    }
+
+    return Arrays.copyOf(data, size);
+  }
+
+  private CelByteString(byte[] buffer) {
+    data = Arrays.copyOf(buffer, buffer.length);
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (o == this) {
+      return true;
+    }
+
+    if (!(o instanceof CelByteString)) {
+      return false;
+    }
+
+    return Arrays.equals(data, ((CelByteString) o).data);
+  }
+
+  /**
+   * Note that we do not use Arrays.hashCode directly due to its implementation using 31 as an odd
+   * prime, which is outdated and is more prone to hash collisions. This code is very similar to
+   * what AutoValue generates.
+   */
+  @Override
+  public int hashCode() {
+    if (hash == 0) {
+      int h = 1;
+      h *= 1000003;
+      h ^= Arrays.hashCode(data);
+      if (h == 0) {
+        h = 1;
+      }
+      hash = h;
+    }
+
+    return hash;
+  }
+}

common/src/main/java/dev/cel/common/values/CelValue.java

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+// Copyright 2023 Google LLC
+//
+// 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
+//
+//      https://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 dev.cel.common.values;
+
+import com.google.errorprone.annotations.Immutable;
+import dev.cel.common.annotations.Internal;
+
+/**
+ * A representation of a CEL value for the runtime. Clients should never directly extend from
+ * CelValue. Clients may extend some subclasses of CelValue, such as StructValue if it has been
+ * explicitly designed and documented for extension.
+ */
+@Immutable
+@Internal
+public abstract class CelValue {
+
+  /**
+   * The underlying value. This is typically the Java native value or a derived instance of CelValue
+   * (ex: an element in lists or key/value pair in maps).
+   */
+  public abstract Object value();
+
+  /** Returns true if the {@link #value()} is a zero value for its type. */
+  public abstract boolean isZeroValue();
+
+  public CelValue() {}
+}

common/src/main/java/dev/cel/common/values/DoubleValue.java

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+// Copyright 2023 Google LLC
+//
+// 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
+//
+//      https://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 dev.cel.common.values;
+
+import com.google.errorprone.annotations.Immutable;
+
+/** DoubleValue is a simple CelValue wrapper around Java doubles. */
+@Immutable
+public final class DoubleValue extends CelValue {
+  private final double value;
+
+  @Override
+  public Double value() {
+    return value;
+  }
+
+  public double doubleValue() {
+    return value;
+  }
+
+  @Override
+  public boolean isZeroValue() {
+    return value() == 0;
+  }
+
+  public static DoubleValue create(double value) {
+    return new DoubleValue(value);
+  }
+
+  @Override
+  public int hashCode() {
+    int h = 1;
+    h *= 1000003;
+    h ^= Double.hashCode(value);
+    return h;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (o == this) {
+      return true;
+    }
+
+    if (!(o instanceof DoubleValue)) {
+      return false;
+    }
+
+    return Double.doubleToLongBits(((DoubleValue) o).doubleValue())
+        == Double.doubleToLongBits(this.doubleValue());
+  }
+
+  private DoubleValue(double value) {
+    this.value = value;
+  }
+}

common/src/main/java/dev/cel/common/values/DurationValue.java

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+// Copyright 2023 Google LLC
+//
+// 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
+//
+//      https://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 dev.cel.common.values;
+
+import com.google.auto.value.AutoValue;
+import com.google.errorprone.annotations.Immutable;
+import java.time.Duration;
+
+/** DurationValue is a simple CelValue wrapper around {@link java.time.Duration} */
+@AutoValue
+@Immutable
+public abstract class DurationValue extends CelValue {
+
+  @Override
+  public abstract Duration value();
+
+  @Override
+  public boolean isZeroValue() {
+    return Duration.ZERO.equals(value());
+  }
+
+  public static DurationValue create(Duration value) {
+    return new AutoValue_DurationValue(value);
+  }
+}