Merge "Initialize rule evaluation engine"

package com.android.server.integrity.engine;

import java.util.ArrayList;

import java.util.List;

/**

 * The engine used to evaluate rules against app installs.

 *

 * <p>Every app install is evaluated against rules (pushed by the verifier) by the evaluation engine

 * to allow/block that install.

 */

public final class RuleEvaluation {

public final class RuleEvaluationEngine {

    private static final String TAG = "RuleEvaluation";

    // TODO: Add singleton injection.

    // The engine for loading rules, retrieving metadata for app installs, and evaluating app

    // installs against rules.

    private static RuleEvaluationEngine sRuleEvaluationEngine;

    // The subset of rules loaded to be used to evaluate an app install request.

    // TODO: Load rules relevant to app installs.

    private List<String> mRules;

    private RuleEvaluationEngine() {

        // Initialize rules with the empty rule set.

        mRules = new ArrayList<>();

    }

    /**

     * Provide a singleton instance of the rule evaluation engine.

     */

    public static synchronized RuleEvaluationEngine getRuleEvaluationEngine() {

        if (sRuleEvaluationEngine == null) {

            return new RuleEvaluationEngine();

        }

        return sRuleEvaluationEngine;

    }

}