ShowCreateViewCommand.java

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// to you under the Apache License, Version 2.0 (the
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//
//   http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.doris.nereids.trees.plans.commands;

import org.apache.doris.catalog.Column;
import org.apache.doris.catalog.DatabaseIf;
import org.apache.doris.catalog.Env;
import org.apache.doris.catalog.MTMV;
import org.apache.doris.catalog.ScalarType;
import org.apache.doris.catalog.TableIf;
import org.apache.doris.catalog.View;
import org.apache.doris.common.AnalysisException;
import org.apache.doris.common.ErrorCode;
import org.apache.doris.common.ErrorReport;
import org.apache.doris.mysql.privilege.PrivPredicate;
import org.apache.doris.nereids.trees.plans.PlanType;
import org.apache.doris.nereids.trees.plans.commands.info.TableNameInfo;
import org.apache.doris.nereids.trees.plans.visitor.PlanVisitor;
import org.apache.doris.qe.ConnectContext;
import org.apache.doris.qe.ShowResultSet;
import org.apache.doris.qe.ShowResultSetMetaData;
import org.apache.doris.qe.StmtExecutor;

import com.google.common.collect.Lists;

import java.util.List;

/**
 * Represents the command for SHOW CREATE VIEW.
 */
public class ShowCreateViewCommand extends ShowCommand {
    private static final ShowResultSetMetaData VIEW_META_DATA =
            ShowResultSetMetaData.builder()
                    .addColumn(new Column("View", ScalarType.createVarchar(20)))
                    .addColumn(new Column("Create View", ScalarType.createVarchar(30)))
                    .addColumn(new Column("character_set_client", ScalarType.createVarchar(30)))
                    .addColumn(new Column("collation_connection", ScalarType.createVarchar(30)))
                    .build();

    private final TableNameInfo tblNameInfo;

    public ShowCreateViewCommand(TableNameInfo tableNameInfo) {
        super(PlanType.SHOW_CREATE_VIEW_COMMAND);
        this.tblNameInfo = tableNameInfo;
    }

    private void validate(ConnectContext ctx) throws AnalysisException {
        tblNameInfo.analyze(ctx);

        TableIf tableIf = Env.getCurrentEnv().getCatalogMgr()
                .getCatalogOrAnalysisException(tblNameInfo.getCtl())
                .getDbOrAnalysisException(tblNameInfo.getDb()).getTableOrAnalysisException(tblNameInfo.getTbl());

        if (tableIf instanceof MTMV) {
            ErrorReport.reportAnalysisException("not support async materialized view, "
                    + "please use `show create materialized view`");
        }

        PrivPredicate wanted;
        if (tableIf instanceof View) {
            wanted = PrivPredicate.SHOW_VIEW;
        } else {
            wanted = PrivPredicate.SHOW;
        }

        if (!Env.getCurrentEnv().getAccessManager().checkTblPriv(ConnectContext.get(),
                tblNameInfo.getCtl(), tblNameInfo.getDb(), tblNameInfo.getTbl(), wanted)) {
            ErrorReport.reportAnalysisException(ErrorCode.ERR_TABLEACCESS_DENIED_ERROR, "SHOW CREATE TABLE",
                                                ConnectContext.get().getQualifiedUser(),
                                                ConnectContext.get().getRemoteIP(),
                                                tblNameInfo.getDb() + ": " + tblNameInfo.getTbl());
        }
    }

    @Override
    public <R, C> R accept(PlanVisitor<R, C> visitor, C context) {
        return visitor.visitShowCreateViewCommand(this, context);
    }

    @Override
    public ShowResultSetMetaData getMetaData() {
        return VIEW_META_DATA;
    }

    @Override
    public ShowResultSet doRun(ConnectContext ctx, StmtExecutor executor) throws Exception {
        validate(ctx);
        // Fetch the catalog, database, and view metadata
        DatabaseIf db = ctx.getEnv().getCatalogMgr().getCatalogOrAnalysisException(tblNameInfo.getCtl())
                        .getDbOrMetaException(tblNameInfo.getDb());
        TableIf view = db.getTableOrMetaException(tblNameInfo.getTbl());

        if (!(view instanceof View)) {
            ErrorReport.reportAnalysisException(ErrorCode.ERR_WRONG_OBJECT, tblNameInfo.getDb(), tblNameInfo.getTbl(),
                        "VIEW", "Use 'SHOW CREATE TABLE '" + tblNameInfo.getTbl());
        }

        List<List<String>> rows = Lists.newArrayList();
        // Lock the view to ensure consistent metadata access
        view.readLock();
        try {
            List<String> createViewStmt = Lists.newArrayList();
            ctx.getEnv().getDdlStmt(null, null, view, createViewStmt, null, null, false, true,
                        false, -1L, false, false);

            if (!createViewStmt.isEmpty()) {
                rows.add(Lists.newArrayList(view.getName(), createViewStmt.get(0), "utf8mb4", "utf8mb4_0900_bin"));
            }
        } finally {
            view.readUnlock();
        }

        // Set the result set and send it using the executor
        return new ShowResultSet(getMetaData(), rows);
    }
}