nullaway/src/main/java/com/uber/nullaway/handlers/MethodParamNullableInjectorHandler.java

/*
 * Copyright (c) 2022 Uber Technologies, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package com.uber.nullaway.handlers;

import com.uber.nullaway.Config;
import com.uber.nullaway.Nullness;
import com.uber.nullaway.dataflow.AccessPath;
import com.uber.nullaway.dataflow.NullnessStore;
import com.uber.nullaway.fixserialization.FixSerializationConfig;
import java.util.List;
import org.checkerframework.nullaway.dataflow.cfg.UnderlyingAST;
import org.checkerframework.nullaway.dataflow.cfg.node.LocalVariableNode;

/**
 * This handler transforms method parameter's state at index {@link
 * FixSerializationConfig#paramTestIndex} for all methods to {@code @Nullable}. It provides the
 * facility to measure protection of methods against nullability of each argument. This handler is
 * activated only if {@link FixSerializationConfig#methodParamProtectionTestEnabled} is enabled.
 */
public class MethodParamNullableInjectorHandler extends BaseNoOpHandler {

  private final FixSerializationConfig config;

  public MethodParamNullableInjectorHandler(Config config) {
    this.config = config.getSerializationConfig();
  }

  @Override
  public NullnessStore.Builder onDataflowInitialStore(
      UnderlyingAST underlyingAST,
      List<LocalVariableNode> parameters,
      NullnessStore.Builder result) {
    int index = config.paramTestIndex;
    if (index >= parameters.size() || !(underlyingAST instanceof UnderlyingAST.CFGMethod)) {
      return super.onDataflowInitialStore(underlyingAST, parameters, result);
    }
    result.setInformation(AccessPath.fromLocal(parameters.get(index)), Nullness.NULLABLE);
    return result;
  }
}