TableUtil.h

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// # TableUtil.h: Utility functions for tables
// # Copyright (C) 2022
// # Associated Universities, Inc. Washington DC, USA.
// #
// # This library is free software; you can redistribute it and/or modify it
// # under the terms of the GNU Library General Public License as published by
// # the Free Software Foundation; either version 2 of the License, or (at your
// # option) any later version.
// #
// # This library is distributed in the hope that it will be useful, but WITHOUT
// # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
// # License for more details.
// #
// # You should have receied a copy of the GNU Library General Public License
// # along with this library; if not, write to the Free Software Foundation,
// # Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
// #
// # Correspondence concerning AIPS++ should be addressed as follows:
// #        Internet email: casa-feedback@nrao.edu.
// #        Postal address: AIPS++ Project Office
// #                        National Radio Astronomy Observatory
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#ifndef TABLES_TABLEUTIL_H
#define TABLES_TABLEUTIL_H
 
#include <casacore/casa/aips.h>
#include <casacore/tables/Tables/Table.h>
#include <casacore/tables/Tables/TableLock.h>
#include <casacore/tables/DataMan/TSMOption.h>
#include <casacore/casa/Containers/Record.h>
#include <casacore/casa/Utilities/DataType.h>
 
namespace casacore {
 
// The TableUtil namespace contains several convenience functions operating
// on Table objects. They make it very convenient to open, close or delete
// main tables and subtables.
// <p>
// The function <src>openTable</src> makes it possible to open a subtable
// of a table in a convenient way, even if the table is only a reference
// to another table (e.g., a selection). The name can be given with colons as
// 'maintab::subtab1::subtab2' meaning that subtab2 is opened and returned.
// Of course, it can also be used to open a main table such as 'my.tab'.
//
// Similar to <src>openTable</src>, the function <src>createTable</src>
// can be used to create a (sub)table, possibly using the :: notation.
// <br><src>deleteTable</src> is similar to delete a (sub)table.
 
namespace TableUtil {
 
// Try to open a table. The name of the table can contain subtable names
// using :: as separator. In this way it is possible to directly open a
// subtable of a RefTable or ConcatTable, which is not possible if the
// table name is specified with slashes.
// <br>The open process is as follows:
// <ul>
//  <li> It is tried to open the table with the given name.
//  <li> If unsuccessful, the name is split into its parts using ::
//       The first part is the main table which will be opened temporarily.
//       The other parts are the successive subtable names (usually one).
//       Each subtable is opened by looking it up in the keywords of the
//       table above. The final subtable is returned.
// </ul>
// <br>An exception is thrown if the table cannot be opened.
// <example>
// Open the ANTENNA subtable of an MS which might be a selection of
// a real MS.
// <srcblock>
// Table tab(Table::openTable ("sel.ms::ANTENNA");
// </srcblock>
// </example>
// <group>
Table openTable(const String& tableName, Table::TableOption = Table::Old,
                const TSMOption& = TSMOption());
Table openTable(const String& tableName, const TableLock& lockOptions,
                Table::TableOption = Table::Old, const TSMOption& = TSMOption());
// </group>
 
// Create a table with the given name and description.
// Datamanager information can be given in the Record.
// The table name can be given with the :: notation meaning that a subtable
// of the previous part is created. Depending on the TableOption, that subtable
// can or cannot exist yet.
// It defines the subtable keyword in the parent table.
// <br>An exception is thrown if one of the parts cannot be opened.
// <example>
// Create the ANT subtable of an MS with some description and create the
// table keyword ANT in sel.ms referring to the subtable.
// It is replaced if already existing (not if TableOption::NewNoReplace is given).
// <srcblock>
// Table tab(Table::createTable ("sel.ms::ANT", someDesc, TableOption::New));
// </srcblock>
// </example>
Table createTable(const String& tableName, const TableDesc&, Table::TableOption,
                  Table::TableType = Table::Plain, const StorageOption& = StorageOption(),
                  const Record& dmInfo = Record(), const TableLock& lockOptions = TableLock(),
                  rownr_t nrrow = 0, Bool initialize = False,
                  Table::EndianFormat = Table::AipsrcEndian, const TSMOption& = TSMOption());
Table createSubTable(Table& parent, const String& subtableName, const TableDesc& desc,
                     Table::TableOption, const StorageOption& = StorageOption(),
                     const Record& dmInfo = Record(), const TableLock& lockOptions = TableLock(),
                     rownr_t nrrow = 0, Bool initialize = False,
                     Table::EndianFormat = Table::AipsrcEndian, const TSMOption& = TSMOption());
 
// Can the table be deleted?
// If true, function deleteTable can safely be called.
// If not, message contains the reason why (e.g. 'table is not writable').
// It checks if the table is writable, is not open in this process
// and is not open in another process.
// If <src>splitColons=True</src> the table name can contain :: to
// denote subtables.
// <br>If <src>checkSubTables</src> is set, it also checks if
// a subtable is not open in another process.
// <br> <src>canDeleteSubTable</src> can be used to check a subtable of the
// given parent.
// <group>
Bool canDeleteTable(const String& tableName, Bool checkSubTables = False);
Bool canDeleteTable(String& message, const String& tableName, Bool checkSubTables = False,
                    Bool splitColons = True);
Bool canDeleteSubTable(String& message, const Table& parent, const String& subtableName,
                       Bool checkSubTables = False);
// </group>
 
// Delete the table.
// An exception is thrown if the table cannot be deleted because
// its is not writable or because it is still open in this or
// another process.
// <br>If <src>checkSubTables</src> is set, it is also checked if
// a subtable is used in another process.
// <br> <src>deleteSubTable</src> can be used to delete a subtable of the
// given parent.
void deleteTable(const String& tableName, Bool checkSubTables = False);
void deleteSubTable(Table& parent, const String& subtableName, Bool checkSubTables = False);
 
// Return the layout of a table (i.e. description and #rows).
// This function has the advantage that only the minimal amount of
// information required is read from the table, thus it is
// faster than a normal table open. The table name can be a subtable using ::.
// <br> The number of rows is returned. The description of the table
// is stored in desc (its contents will be overwritten).
// <br> An exception is thrown if the table does not exist.
rownr_t getLayout(TableDesc& desc, const String& tableName);
 
// Get the table info of the table with the given name.
// An empty object is returned if the table is unknown.
// The table name can be a subtable using ::.
TableInfo tableInfo(const String& tableName);
 
// Get the full name (absolute path) of the given table name, which can
// be a subtable specification using ::.
String getFullName(const String& tableName);
 
// Find the parent table of the last subtable in a table name containing
// :: to indicate subtables.
// It returns the Table object of that parent table and the name of
// the last subtable. An empty Table is returned if the table name does
// not contain subtable names.
// In case of an error, an exception is thrown.
std::pair<Table, String> findParentTable(const String& fullName,
                                         const TableLock& lockOptions = TableLock(),
                                         Table::TableOption option = Table::Old,
                                         const TSMOption& tsmOption = TSMOption());
 
}  // namespace TableUtil
}  // namespace casacore
 
#endif