content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to you 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 org.apache.calcite.jdbc;
  
  import org.apache.calcite.DataContext;
  import org.apache.calcite.adapter.java.JavaTypeFactory;
  import org.apache.calcite.avatica.AvaticaParameter;
  import org.apache.calcite.avatica.ColumnMetaData;
  import org.apache.calcite.avatica.Meta;
  import org.apache.calcite.config.CalciteConnectionConfig;
  import org.apache.calcite.linq4j.Enumerable;
  import org.apache.calcite.linq4j.EnumerableDefaults;
  import org.apache.calcite.linq4j.Queryable;
  import org.apache.calcite.linq4j.function.Function0;
  import org.apache.calcite.linq4j.tree.ClassDeclaration;
  import org.apache.calcite.plan.RelOptPlanner;
  import org.apache.calcite.plan.RelOptRule;
  import org.apache.calcite.prepare.CalcitePrepareImpl;
  import org.apache.calcite.rel.RelCollation;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.RelRoot;
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.rel.type.RelDataTypeFactory;
  import org.apache.calcite.rex.RexNode;
  import org.apache.calcite.runtime.ArrayBindable;
  import org.apache.calcite.runtime.Bindable;
  import org.apache.calcite.schema.Table;
  import org.apache.calcite.sql.SqlKind;
  import org.apache.calcite.sql.SqlNode;
  import org.apache.calcite.sql.validate.CyclicDefinitionException;
  import org.apache.calcite.sql.validate.SqlValidator;
  import org.apache.calcite.tools.RelRunner;
  import org.apache.calcite.util.ImmutableIntList;
  import org.apache.calcite.util.TryThreadLocal;
  
  import com.fasterxml.jackson.annotation.JsonIgnore;
  import com.google.common.collect.ImmutableList;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  import java.lang.reflect.Type;
  import java.util.ArrayDeque;
  import java.util.Deque;
  import java.util.List;
  import java.util.Map;
  
  import static com.google.common.base.Preconditions.checkArgument;
  
  import static org.apache.calcite.linq4j.Nullness.castNonNull;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * API for a service that prepares statements for execution.
   */
  public interface CalcitePrepare {
    Function0<CalcitePrepare> DEFAULT_FACTORY = CalcitePrepareImpl::new;
    TryThreadLocal<Deque<Context>> THREAD_CONTEXT_STACK =
        TryThreadLocal.withInitial(ArrayDeque::new);
  
    ParseResult parse(Context context, String sql);
  
    ConvertResult convert(Context context, String sql);
  
    /** Executes a DDL statement.
     *
     * <p>The statement identified itself as DDL in the
     * {@link org.apache.calcite.jdbc.CalcitePrepare.ParseResult#kind} field. */
    void executeDdl(Context context, SqlNode node);
  
    /** Analyzes a view.
     *
     * @param context Context
     * @param sql View SQL
     * @param fail Whether to fail (and throw a descriptive error message) if the
     *             view is not modifiable
     * @return Result of analyzing the view
     */
    AnalyzeViewResult analyzeView(Context context, String sql, boolean fail);
  
    <T> CalciteSignature<T> prepareSql(
        Context context,
        Query<T> query,
        Type elementType,
        long maxRowCount);
  
    <T> CalciteSignature<T> prepareQueryable(
        Context context,
        Queryable<T> queryable);
  
    /** Context for preparing a statement. */
    interface Context {
      JavaTypeFactory getTypeFactory();
  
      /** Returns the root schema for statements that need a read-consistent
       * snapshot. */
      CalciteSchema getRootSchema();
  
      /** Returns the root schema for statements that need to be able to modify
       * schemas and have the results available to other statements. Viz, DDL
       * statements. */
      CalciteSchema getMutableRootSchema();
  
      List<String> getDefaultSchemaPath();
  
      CalciteConnectionConfig config();
  
      /** Returns the spark handler. Never null. */
      SparkHandler spark();
  
      DataContext getDataContext();
  
      /** Returns the path of the object being analyzed, or null.
       *
       * <p>The object is being analyzed is typically a view. If it is already
       * being analyzed further up the stack, the view definition can be deduced
       * to be cyclic. */
      @Nullable List<String> getObjectPath();
  
      /** Gets a runner; it can execute a relational expression. */
      RelRunner getRelRunner();
    }
  
    /** Callback to register Spark as the main engine. */
    interface SparkHandler {
      RelNode flattenTypes(RelOptPlanner planner, RelNode rootRel,
          boolean restructure);
  
      void registerRules(RuleSetBuilder builder);
  
      boolean enabled();
  
      ArrayBindable compile(ClassDeclaration expr, String s);
  
      Object sparkContext();
  
      /** Allows Spark to declare the rules it needs. */
      interface RuleSetBuilder {
        void addRule(RelOptRule rule);
        void removeRule(RelOptRule rule);
      }
    }
  
    /** Namespace that allows us to define non-abstract methods inside an
     * interface. */
    class Dummy {
      private static @Nullable SparkHandler sparkHandler;
  
      private Dummy() {}
  
      /** Returns a spark handler. Returns a trivial handler, for which
       * {@link SparkHandler#enabled()} returns {@code false}, if {@code enable}
       * is {@code false} or if Spark is not on the class path. Never returns
       * null. */
      public static synchronized SparkHandler getSparkHandler(boolean enable) {
        if (sparkHandler == null) {
          sparkHandler = enable ? createHandler() : new TrivialSparkHandler();
        }
        return sparkHandler;
      }
  
      private static SparkHandler createHandler() {
        try {
          final Class<?> clazz =
              Class.forName("org.apache.calcite.adapter.spark.SparkHandlerImpl");
          Method method = clazz.getMethod("instance");
          return (CalcitePrepare.SparkHandler) requireNonNull(
              method.invoke(null),
              () -> "non-null SparkHandler expected from " + method);
        } catch (ClassNotFoundException e) {
          return new TrivialSparkHandler();
        } catch (IllegalAccessException
            | ClassCastException
            | InvocationTargetException
            | NoSuchMethodException e) {
          throw new RuntimeException(e);
        }
      }
  
      public static void push(Context context) {
        final Deque<Context> stack = THREAD_CONTEXT_STACK.get();
        final List<String> path = context.getObjectPath();
        if (path != null) {
          for (Context context1 : stack) {
            final List<String> path1 = context1.getObjectPath();
            if (path.equals(path1)) {
              throw new CyclicDefinitionException(stack.size(), path);
            }
          }
        }
        stack.push(context);
      }
  
      public static Context peek() {
        final Deque<Context> stack = THREAD_CONTEXT_STACK.get();
        return castNonNull(stack.peek());
      }
  
      public static void pop(Context context) {
        final Deque<Context> stack = THREAD_CONTEXT_STACK.get();
        Context x = castNonNull(stack).pop();
        assert x == context;
      }
  
      /** Implementation of {@link SparkHandler} that either does nothing or
       * throws for each method. Use this if Spark is not installed. */
      private static class TrivialSparkHandler implements SparkHandler {
        @Override public RelNode flattenTypes(RelOptPlanner planner, RelNode rootRel,
            boolean restructure) {
          return rootRel;
        }
  
        @Override public void registerRules(RuleSetBuilder builder) {
        }
  
        @Override public boolean enabled() {
          return false;
        }
  
        @Override public ArrayBindable compile(ClassDeclaration expr, String s) {
          throw new UnsupportedOperationException();
        }
  
        @Override public Object sparkContext() {
          throw new UnsupportedOperationException();
        }
      }
  
    }
  
    /** The result of parsing and validating a SQL query. */
    class ParseResult {
      public final CalcitePrepareImpl prepare;
      public final String sql; // for debug
      public final SqlNode sqlNode;
      public final RelDataType rowType;
      public final RelDataTypeFactory typeFactory;
  
      public ParseResult(CalcitePrepareImpl prepare, SqlValidator validator,
          String sql,
          SqlNode sqlNode, RelDataType rowType) {
        super();
        this.prepare = prepare;
        this.sql = sql;
        this.sqlNode = sqlNode;
        this.rowType = rowType;
        this.typeFactory = validator.getTypeFactory();
      }
  
      /** Returns the kind of statement.
       *
       * <p>Possibilities include:
       *
       * <ul>
       *   <li>Queries: usually {@link SqlKind#SELECT}, but
       *   other query operators such as {@link SqlKind#UNION} and
       *   {@link SqlKind#ORDER_BY} are possible
       *   <li>DML statements: {@link SqlKind#INSERT}, {@link SqlKind#UPDATE} etc.
       *   <li>Session control statements: {@link SqlKind#COMMIT}
       *   <li>DDL statements: {@link SqlKind#CREATE_TABLE},
       *   {@link SqlKind#DROP_INDEX}
       * </ul>
       *
       * @return Kind of statement, never null
       */
      public SqlKind kind() {
        return sqlNode.getKind();
      }
    }
  
    /** The result of parsing and validating a SQL query and converting it to
     * relational algebra. */
    class ConvertResult extends ParseResult {
      public final RelRoot root;
  
      public ConvertResult(CalcitePrepareImpl prepare, SqlValidator validator,
          String sql, SqlNode sqlNode, RelDataType rowType, RelRoot root) {
        super(prepare, validator, sql, sqlNode, rowType);
        this.root = root;
      }
    }
  
    /** The result of analyzing a view. */
    class AnalyzeViewResult extends ConvertResult {
      /** Not null if and only if the view is modifiable. */
      public final @Nullable Table table;
      public final @Nullable ImmutableList<String> tablePath;
      public final @Nullable RexNode constraint;
      public final @Nullable ImmutableIntList columnMapping;
      public final boolean modifiable;
  
      public AnalyzeViewResult(CalcitePrepareImpl prepare,
          SqlValidator validator, String sql, SqlNode sqlNode,
          RelDataType rowType, RelRoot root, @Nullable Table table,
          @Nullable ImmutableList<String> tablePath, @Nullable RexNode constraint,
          @Nullable ImmutableIntList columnMapping, boolean modifiable) {
        super(prepare, validator, sql, sqlNode, rowType, root);
        this.table = table;
        this.tablePath = tablePath;
        this.constraint = constraint;
        this.columnMapping = columnMapping;
        this.modifiable = modifiable;
        checkArgument(modifiable == (table != null));
      }
    }
  
    /** The result of preparing a query. It gives the Avatica driver framework
     * the information it needs to create a prepared statement, or to execute a
     * statement directly, without an explicit prepare step.
     *
     * @param <T> element type */
    class CalciteSignature<T> extends Meta.Signature {
      @JsonIgnore public final @Nullable RelDataType rowType;
      @JsonIgnore public final @Nullable CalciteSchema rootSchema;
      @JsonIgnore private final List<RelCollation> collationList;
      private final long maxRowCount;
      private final @Nullable Bindable<T> bindable;
  
      @Deprecated // to be removed before 2.0
      public CalciteSignature(String sql, List<AvaticaParameter> parameterList,
          Map<String, Object> internalParameters, RelDataType rowType,
          List<ColumnMetaData> columns, Meta.CursorFactory cursorFactory,
          CalciteSchema rootSchema, List<RelCollation> collationList,
          long maxRowCount, Bindable<T> bindable) {
        this(sql, parameterList, internalParameters, rowType, columns,
            cursorFactory, rootSchema, collationList, maxRowCount, bindable,
            castNonNull(null));
      }
  
      public CalciteSignature(@Nullable String sql,
          List<AvaticaParameter> parameterList,
          Map<String, Object> internalParameters,
          @Nullable RelDataType rowType,
          List<ColumnMetaData> columns,
          Meta.CursorFactory cursorFactory,
          @Nullable CalciteSchema rootSchema,
          List<RelCollation> collationList,
          long maxRowCount,
          @Nullable Bindable<T> bindable,
          Meta.StatementType statementType) {
        super(columns, sql, parameterList, internalParameters, cursorFactory,
            statementType);
        this.rowType = rowType;
        this.rootSchema = rootSchema;
        this.collationList = collationList;
        this.maxRowCount = maxRowCount;
        this.bindable = bindable;
      }
  
      public Enumerable<T> enumerable(DataContext dataContext) {
        Enumerable<T> enumerable = castNonNull(bindable).bind(dataContext);
        if (maxRowCount >= 0) {
          // Apply limit. In JDBC 0 means "no limit". But for us, -1 means
          // "no limit", and 0 is a valid limit.
          enumerable = EnumerableDefaults.take(enumerable, maxRowCount);
        }
        return enumerable;
      }
  
      public List<RelCollation> getCollationList() {
        return collationList;
      }
    }
  
    /** A union type of the three possible ways of expressing a query: as a SQL
     * string, a {@link Queryable} or a {@link RelNode}. Exactly one must be
     * provided.
     *
     * @param <T> element type */
    class Query<T> {
      public final @Nullable String sql;
      public final @Nullable Queryable<T> queryable;
      public final @Nullable RelNode rel;
  
      private Query(@Nullable String sql, @Nullable Queryable<T> queryable, @Nullable RelNode rel) {
        this.sql = sql;
        this.queryable = queryable;
        this.rel = rel;
  
        assert (sql == null ? 0 : 1)
            + (queryable == null ? 0 : 1)
            + (rel == null ? 0 : 1) == 1;
      }
  
      public static <T> Query<T> of(String sql) {
        return new Query<>(sql, null, null);
      }
  
      public static <T> Query<T> of(Queryable<T> queryable) {
        return new Query<>(null, queryable, null);
      }
  
      public static <T> Query<T> of(RelNode rel) {
        return new Query<>(null, null, rel);
      }
    }
  }
  