Add general interfaces for instantiating a CelOptimizer

PiperOrigin-RevId: 563878390

optimizer/BUILD.bazel

@@ -0,0 +1,26 @@
+package(
+    default_applicable_licenses = ["//:license"],
+    default_visibility = ["//visibility:public"],  # TODO: Expose to public
+)
+
+java_library(
+    name = "optimizer",
+    exports = ["//optimizer/src/main/java/dev/cel/optimizer"],
+)
+
+java_library(
+    name = "optimizer_builder",
+    exports = ["//optimizer/src/main/java/dev/cel/optimizer:optimizer_builder"],
+)
+
+java_library(
+    name = "ast_optimizer",
+    exports = ["//optimizer/src/main/java/dev/cel/optimizer:ast_optimizer"],
+)
+
+java_library(
+    name = "optimizer_impl",
+    testonly = 1,
+    visibility = ["//optimizer/src/test/java/dev/cel/optimizer:__pkg__"],
+    exports = ["//optimizer/src/main/java/dev/cel/optimizer:optimizer_impl"],
+)

optimizer/src/main/java/dev/cel/optimizer/BUILD.bazel

@@ -0,0 +1,71 @@
+package(
+    default_applicable_licenses = ["//:license"],
+    default_visibility = [
+        "//visibility:public",
+    ],
+)
+
+java_library(
+    name = "optimizer",
+    srcs = [
+        "CelOptimizerFactory.java",
+    ],
+    tags = [
+    ],
+    deps = [
+        ":optimizer_impl",
+        "//bundle:cel",
+        "//checker:checker_builder",
+        "//compiler",
+        "//compiler:compiler_builder",
+        "//optimizer:optimizer_builder",
+        "//parser:parser_builder",
+        "//runtime",
+    ],
+)
+
+java_library(
+    name = "optimizer_builder",
+    srcs = [
+        "CelOptimizer.java",
+        "CelOptimizerBuilder.java",
+    ],
+    tags = [
+    ],
+    deps = [
+        ":ast_optimizer",
+        "//common",
+        "//common:compiler_common",
+        "@maven//:com_google_errorprone_error_prone_annotations",
+    ],
+)
+
+java_library(
+    name = "optimizer_impl",
+    srcs = [
+        "CelOptimizerImpl.java",
+    ],
+    tags = [
+    ],
+    deps = [
+        ":ast_optimizer",
+        ":optimizer_builder",
+        "//bundle:cel",
+        "//common",
+        "//common:compiler_common",
+        "//common/navigation",
+        "@maven//:com_google_guava_guava",
+    ],
+)
+
+java_library(
+    name = "ast_optimizer",
+    srcs = ["CelAstOptimizer.java"],
+    tags = [
+    ],
+    deps = [
+        "//bundle:cel",
+        "//common",
+        "//common/navigation",
+    ],
+)

optimizer/src/main/java/dev/cel/optimizer/CelAstOptimizer.java

@@ -0,0 +1,28 @@
+// 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.optimizer;
+
+import dev.cel.bundle.Cel;
+import dev.cel.common.CelAbstractSyntaxTree;
+import dev.cel.common.navigation.CelNavigableAst;
+
+/** Public interface for performing a single, custom optimization on an AST. */
+public interface CelAstOptimizer {
+
+  /**
+   * Optimizes a single AST.
+   **/
+  CelAbstractSyntaxTree optimize(CelNavigableAst navigableAst, Cel cel);
+}

optimizer/src/main/java/dev/cel/optimizer/CelOptimizer.java

@@ -0,0 +1,38 @@
+// 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.optimizer;
+
+import dev.cel.common.CelAbstractSyntaxTree;
+import dev.cel.common.CelValidationException;
+
+/** Public interface for optimizing an AST. */
+public interface CelOptimizer {
+
+  /**
+   * Performs custom optimization of the provided AST.
+   *
+   * <p>This invokes all the AST optimizers present in this CelOptimizer instance via {@link
+   * CelOptimizerBuilder#addAstOptimizers} in their added order. Any exceptions thrown within the
+   * AST optimizer will be propagated to the caller and will abort the optimization process.
+   *
+   * <p>Note that the produced expression string from unparsing an optimized AST will likely not be
+   * equal to the original expression.
+   *
+   * @param ast A type-checked AST.
+   * @throws CelValidationException If the optimized AST fails to type-check after a single
+   *     optimization pass.
+   */
+  CelAbstractSyntaxTree optimize(CelAbstractSyntaxTree ast) throws CelValidationException;
+}

optimizer/src/main/java/dev/cel/optimizer/CelOptimizerBuilder.java

@@ -0,0 +1,34 @@
+// 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.optimizer;
+
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
+import com.google.errorprone.annotations.CheckReturnValue;
+
+/** Interface for building an instance of CelOptimizer. */
+public interface CelOptimizerBuilder {
+
+  /** Adds one or more optimizer to perform custom AST optimizations. */
+  @CanIgnoreReturnValue
+  CelOptimizerBuilder addAstOptimizers(CelAstOptimizer... astOptimizers);
+
+  /** Adds one or more optimizer to perform custom AST optimizations. */
+  @CanIgnoreReturnValue
+  CelOptimizerBuilder addAstOptimizers(Iterable<CelAstOptimizer> astOptimizers);
+
+  /** Build a new instance of the {@link CelOptimizer}. */
+  @CheckReturnValue
+  CelOptimizer build();
+}

optimizer/src/main/java/dev/cel/optimizer/CelOptimizerFactory.java

@@ -0,0 +1,47 @@
+// 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.optimizer;
+
+import dev.cel.bundle.Cel;
+import dev.cel.bundle.CelFactory;
+import dev.cel.checker.CelChecker;
+import dev.cel.compiler.CelCompiler;
+import dev.cel.compiler.CelCompilerFactory;
+import dev.cel.parser.CelParser;
+import dev.cel.runtime.CelRuntime;
+
+/** Factory class for constructing an {@link CelOptimizer} instance. */
+public final class CelOptimizerFactory {
+
+  /** Create a new builder for constructing a {@link CelOptimizer} instance. */
+  public static CelOptimizerBuilder standardCelOptimizerBuilder(Cel cel) {
+    return CelOptimizerImpl.newBuilder(cel);
+  }
+
+  /** Create a new builder for constructing a {@link CelOptimizer} instance. */
+  public static CelOptimizerBuilder standardCelOptimizerBuilder(
+      CelCompiler celCompiler, CelRuntime celRuntime) {
+    return standardCelOptimizerBuilder(CelFactory.combine(celCompiler, celRuntime));
+  }
+
+  /** Create a new builder for constructing a {@link CelOptimizer} instance. */
+  public static CelOptimizerBuilder standardCelOptimizerBuilder(
+      CelParser celParser, CelChecker celChecker, CelRuntime celRuntime) {
+    return standardCelOptimizerBuilder(
+        CelCompilerFactory.combine(celParser, celChecker), celRuntime);
+  }
+
+  private CelOptimizerFactory() {}
+}

optimizer/src/main/java/dev/cel/optimizer/CelOptimizerImpl.java

@@ -0,0 +1,84 @@
+// 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.optimizer;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import com.google.common.collect.ImmutableSet;
+import dev.cel.bundle.Cel;
+import dev.cel.common.CelAbstractSyntaxTree;
+import dev.cel.common.CelValidationException;
+import dev.cel.common.navigation.CelNavigableAst;
+import java.util.Arrays;
+
+final class CelOptimizerImpl implements CelOptimizer {
+  private final Cel cel;
+  private final ImmutableSet<CelAstOptimizer> astOptimizers;
+
+  CelOptimizerImpl(Cel cel, ImmutableSet<CelAstOptimizer> astOptimizers) {
+    this.cel = cel;
+    this.astOptimizers = astOptimizers;
+  }
+
+  @Override
+  public CelAbstractSyntaxTree optimize(CelAbstractSyntaxTree ast) throws CelValidationException {
+    if (!ast.isChecked()) {
+      throw new IllegalArgumentException("AST must be type-checked.");
+    }
+
+    CelAbstractSyntaxTree optimizedAst = ast;
+    for (CelAstOptimizer optimizer : astOptimizers) {
+      CelNavigableAst navigableAst = CelNavigableAst.fromAst(ast);
+      optimizedAst = optimizer.optimize(navigableAst, cel);
+      optimizedAst = cel.check(optimizedAst).getAst();
+    }
+
+    return optimizedAst;
+  }
+
+  /** Create a new builder for constructing a {@link CelOptimizer} instance. */
+  static CelOptimizerImpl.Builder newBuilder(Cel cel) {
+    return new CelOptimizerImpl.Builder(cel);
+  }
+
+  /** Builder class for {@link CelOptimizerImpl}. */
+  static final class Builder implements CelOptimizerBuilder {
+    private final Cel cel;
+    private final ImmutableSet.Builder<CelAstOptimizer> astOptimizers;
+
+    private Builder(Cel cel) {
+      this.cel = cel;
+      this.astOptimizers = ImmutableSet.builder();
+    }
+
+    @Override
+    public CelOptimizerBuilder addAstOptimizers(CelAstOptimizer... astOptimizers) {
+      checkNotNull(astOptimizers);
+      return addAstOptimizers(Arrays.asList(astOptimizers));
+    }
+
+    @Override
+    public CelOptimizerBuilder addAstOptimizers(Iterable<CelAstOptimizer> astOptimizers) {
+      checkNotNull(astOptimizers);
+      this.astOptimizers.addAll(astOptimizers);
+      return this;
+    }
+
+    @Override
+    public CelOptimizer build() {
+      return new CelOptimizerImpl(cel, astOptimizers.build());
+    }
+  }
+}

optimizer/src/test/java/dev/cel/optimizer/BUILD.bazel

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+load("//:testing.bzl", "junit4_test_suites")
+
+package(default_applicable_licenses = ["//:license"])
+
+java_library(
+    name = "tests",
+    testonly = 1,
+    srcs = glob(["*.java"]),
+    deps = [
+        "//:java_truth",
+        "//bundle:cel",
+        "//common",
+        "//common:compiler_common",
+        "//common/ast",
+        "//compiler",
+        "//optimizer",
+        "//optimizer:optimizer_builder",
+        "//optimizer:optimizer_impl",
+        "//parser",
+        "//runtime",
+        "@maven//:junit_junit",
+    ],
+)
+
+junit4_test_suites(
+    name = "test_suites",
+    sizes = [
+        "small",
+    ],
+    src_dir = "src/test/java",
+    deps = [":tests"],
+)