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- /**
- * @license Copyright (c) 2003-2020, CKSource - Frederico Knabben. All rights reserved.
- * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
- */
- /**
- * @module table/converters/table-layout-post-fixer
- */
- import TableWalker from './../tablewalker';
- import { createEmptyTableCell, updateNumericAttribute } from '../utils/common';
- /**
- * Injects a table layout post-fixer into the model.
- *
- * The role of the table layout post-fixer is to ensure that the table rows have the correct structure
- * after a {@link module:engine/model/model~Model#change `change()`} block was executed.
- *
- * The correct structure means that:
- *
- * * All table rows have the same size.
- * * None of the table cells extend vertically beyond their section (either header or body).
- * * A table cell has always at least one element as a child.
- *
- * If the table structure is not correct, the post-fixer will automatically correct it in two steps:
- *
- * 1. It will clip table cells that extend beyond their section.
- * 2. It will add empty table cells to the rows that are narrower than the widest table row.
- *
- * ## Clipping overlapping table cells
- *
- * Such situation may occur when pasting a table (or a part of a table) to the editor from external sources.
- *
- * For example, see the following table which has a cell (FOO) with the rowspan attribute (2):
- *
- * <table headingRows="1">
- * <tableRow>
- * <tableCell rowspan="2"><paragraph>FOO</paragraph></tableCell>
- * <tableCell colspan="2"><paragraph>BAR</paragraph></tableCell>
- * </tableRow>
- * <tableRow>
- * <tableCell><paragraph>BAZ</paragraph></tableCell>
- * <tableCell><paragraph>XYZ</paragraph></tableCell>
- * </tableRow>
- * </table>
- *
- * It will be rendered in the view as:
- *
- * <table>
- * <thead>
- * <tr>
- * <td rowspan="2">FOO</td>
- * <td colspan="2">BAR</td>
- * </tr>
- * </thead>
- * <tbody>
- * <tr>
- * <td>BAZ</td>
- * <td>XYZ</td>
- * </tr>
- * </tbody>
- * </table>
- *
- * In the above example the table will be rendered as a table with two rows: one in the header and second one in the body.
- * The table cell (FOO) cannot span over multiple rows as it would extend from the header to the body section.
- * The `rowspan` attribute must be changed to (1). The value (1) is the default value of the `rowspan` attribute
- * so the `rowspan` attribute will be removed from the model.
- *
- * The table cell with BAZ in the content will be in the first column of the table.
- *
- * ## Adding missing table cells
- *
- * The table post-fixer will insert empty table cells to equalize table row sizes (the number of columns).
- * The size of a table row is calculated by counting column spans of table cells, both horizontal (from the same row) and
- * vertical (from the rows above).
- *
- * In the above example, the table row in the body section of the table is narrower then the row from the header: it has two cells
- * with the default colspan (1). The header row has one cell with colspan (1) and the second with colspan (2).
- * The table cell (FOO) does not extend beyond the head section (and as such will be fixed in the first step of this post-fixer).
- * The post-fixer will add a missing table cell to the row in the body section of the table.
- *
- * The table from the above example will be fixed and rendered to the view as below:
- *
- * <table>
- * <thead>
- * <tr>
- * <td rowspan="2">FOO</td>
- * <td colspan="2">BAR</td>
- * </tr>
- * </thead>
- * <tbody>
- * <tr>
- * <td>BAZ</td>
- * <td>XYZ</td>
- * </tr>
- * </tbody>
- * </table>
- *
- * ## Collaboration and undo - Expectations vs post-fixer results
- *
- * The table post-fixer only ensures proper structure without a deeper analysis of the nature of the change. As such, it might lead
- * to a structure which was not intended by the user. In particular, it will also fix undo steps (in conjunction with collaboration)
- * in which the editor content might not return to the original state.
- *
- * This will usually happen when one or more users change the size of the table.
- *
- * As an example see the table below:
- *
- * <table>
- * <tbody>
- * <tr>
- * <td>11</td>
- * <td>12</td>
- * </tr>
- * <tr>
- * <td>21</td>
- * <td>22</td>
- * </tr>
- * </tbody>
- * </table>
- *
- * and the user actions:
- *
- * 1. Both users have a table with two rows and two columns.
- * 2. User A adds a column at the end of the table. This will insert empty table cells to two rows.
- * 3. User B adds a row at the end of the table. This will insert a row with two empty table cells.
- * 4. Both users will have a table as below:
- *
- *
- * <table>
- * <tbody>
- * <tr>
- * <td>11</td>
- * <td>12</td>
- * <td>(empty, inserted by A)</td>
- * </tr>
- * <tr>
- * <td>21</td>
- * <td>22</td>
- * <td>(empty, inserted by A)</td>
- * </tr>
- * <tr>
- * <td>(empty, inserted by B)</td>
- * <td>(empty, inserted by B)</td>
- * </tr>
- * </tbody>
- * </table>
- *
- * The last row is shorter then others so the table post-fixer will add an empty row to the last row:
- *
- * <table>
- * <tbody>
- * <tr>
- * <td>11</td>
- * <td>12</td>
- * <td>(empty, inserted by A)</td>
- * </tr>
- * <tr>
- * <td>21</td>
- * <td>22</td>
- * <td>(empty, inserted by A)</td>
- * </tr>
- * <tr>
- * <td>(empty, inserted by B)</td>
- * <td>(empty, inserted by B)</td>
- * <td>(empty, inserted by the post-fixer)</td>
- * </tr>
- * </tbody>
- * </table>
- *
- * Unfortunately undo does not know the nature of the changes and depending on which user applies the post-fixer changes, undoing them
- * might lead to a broken table. If User B undoes inserting the column to the table, the undo engine will undo only the operations of
- * inserting empty cells to rows from the initial table state (row 1 and 2) but the cell in the post-fixed row will remain:
- *
- * <table>
- * <tbody>
- * <tr>
- * <td>11</td>
- * <td>12</td>
- * </tr>
- * <tr>
- * <td>21</td>
- * <td>22</td>
- * </tr>
- * <tr>
- * <td>(empty, inserted by B)</td>
- * <td>(empty, inserted by B)</td>
- * <td>(empty, inserted by a post-fixer)</td>
- * </tr>
- * </tbody>
- * </table>
- *
- * After undo, the table post-fixer will detect that two rows are shorter than others and will fix the table to:
- *
- * <table>
- * <tbody>
- * <tr>
- * <td>11</td>
- * <td>12</td>
- * <td>(empty, inserted by a post-fixer after undo)</td>
- * </tr>
- * <tr>
- * <td>21</td>
- * <td>22</td>
- * <td>(empty, inserted by a post-fixer after undo)</td>
- * </tr>
- * <tr>
- * <td>(empty, inserted by B)</td>
- * <td>(empty, inserted by B)</td>
- * <td>(empty, inserted by a post-fixer)</td>
- * </tr>
- * </tbody>
- * </table>
- * @param {module:engine/model/model~Model} model
- */
- export default function injectTableLayoutPostFixer( model ) {
- model.document.registerPostFixer( writer => tableLayoutPostFixer( writer, model ) );
- }
- // The table layout post-fixer.
- //
- // @param {module:engine/model/writer~Writer} writer
- // @param {module:engine/model/model~Model} model
- function tableLayoutPostFixer( writer, model ) {
- const changes = model.document.differ.getChanges();
- let wasFixed = false;
- // Do not analyze the same table more then once - may happen for multiple changes in the same table.
- const analyzedTables = new Set();
- for ( const entry of changes ) {
- let table;
- if ( entry.name == 'table' && entry.type == 'insert' ) {
- table = entry.position.nodeAfter;
- }
- // Fix table on adding/removing table cells and rows.
- if ( entry.name == 'tableRow' || entry.name == 'tableCell' ) {
- table = entry.position.findAncestor( 'table' );
- }
- // Fix table on any table's attribute change - including attributes of table cells.
- if ( isTableAttributeEntry( entry ) ) {
- table = entry.range.start.findAncestor( 'table' );
- }
- if ( table && !analyzedTables.has( table ) ) {
- // Step 1: correct rowspans of table cells if necessary.
- // The wasFixed flag should be true if any of tables in batch was fixed - might be more then one.
- wasFixed = fixTableCellsRowspan( table, writer ) || wasFixed;
- // Step 2: fix table rows sizes.
- wasFixed = fixTableRowsSizes( table, writer ) || wasFixed;
- analyzedTables.add( table );
- }
- }
- return wasFixed;
- }
- // Fixes the invalid value of the `rowspan` attribute because a table cell cannot vertically extend beyond the table section it belongs to.
- //
- // @param {module:engine/model/element~Element} table
- // @param {module:engine/model/writer~Writer} writer
- // @returns {Boolean} Returns `true` if the table was fixed.
- function fixTableCellsRowspan( table, writer ) {
- let wasFixed = false;
- const cellsToTrim = findCellsToTrim( table );
- if ( cellsToTrim.length ) {
- // @if CK_DEBUG_TABLE // console.log( `Post-fixing table: trimming cells row-spans (${ cellsToTrim.length }).` );
- wasFixed = true;
- for ( const data of cellsToTrim ) {
- updateNumericAttribute( 'rowspan', data.rowspan, data.cell, writer, 1 );
- }
- }
- return wasFixed;
- }
- // Makes all table rows in a table the same size.
- //
- // @param {module:engine/model/element~Element} table
- // @param {module:engine/model/writer~Writer} writer
- // @returns {Boolean} Returns `true` if the table was fixed.
- function fixTableRowsSizes( table, writer ) {
- let wasFixed = false;
- const rowsLengths = getRowsLengths( table );
- const rowsToRemove = [];
- // Find empty rows.
- for ( const [ rowIndex, size ] of rowsLengths.entries() ) {
- if ( !size ) {
- rowsToRemove.push( rowIndex );
- }
- }
- // Remove empty rows.
- if ( rowsToRemove.length ) {
- // @if CK_DEBUG_TABLE // console.log( `Post-fixing table: remove empty rows (${ rowsToRemove.length }).` );
- wasFixed = true;
- for ( const rowIndex of rowsToRemove.reverse() ) {
- writer.remove( table.getChild( rowIndex ) );
- rowsLengths.splice( rowIndex, 1 );
- }
- }
- // Verify if all the rows have the same number of columns.
- const tableSize = rowsLengths[ 0 ];
- const isValid = rowsLengths.every( length => length === tableSize );
- if ( !isValid ) {
- // @if CK_DEBUG_TABLE // console.log( 'Post-fixing table: adding missing cells.' );
- // Find the maximum number of columns.
- const maxColumns = rowsLengths.reduce( ( prev, current ) => current > prev ? current : prev, 0 );
- for ( const [ rowIndex, size ] of rowsLengths.entries() ) {
- const columnsToInsert = maxColumns - size;
- if ( columnsToInsert ) {
- for ( let i = 0; i < columnsToInsert; i++ ) {
- createEmptyTableCell( writer, writer.createPositionAt( table.getChild( rowIndex ), 'end' ) );
- }
- wasFixed = true;
- }
- }
- }
- return wasFixed;
- }
- // Searches for table cells that extend beyond the table section to which they belong to. It will return an array of objects
- // that stores table cells to be trimmed and the correct value of the `rowspan` attribute to set.
- //
- // @param {module:engine/model/element~Element} table
- // @returns {Array.<{{cell, rowspan}}>}
- function findCellsToTrim( table ) {
- const headingRows = parseInt( table.getAttribute( 'headingRows' ) || 0 );
- const maxRows = table.childCount;
- const cellsToTrim = [];
- for ( const { row, cell, cellHeight } of new TableWalker( table ) ) {
- // Skip cells that do not expand over its row.
- if ( cellHeight < 2 ) {
- continue;
- }
- const isInHeader = row < headingRows;
- // Row limit is either end of header section or whole table as table body is after the header.
- const rowLimit = isInHeader ? headingRows : maxRows;
- // If table cell expands over its limit reduce it height to proper value.
- if ( row + cellHeight > rowLimit ) {
- const newRowspan = rowLimit - row;
- cellsToTrim.push( { cell, rowspan: newRowspan } );
- }
- }
- return cellsToTrim;
- }
- // Returns an array with lengths of rows assigned to the corresponding row index.
- //
- // @param {module:engine/model/element~Element} table
- // @returns {Array.<Number>}
- function getRowsLengths( table ) {
- // TableWalker will not provide items for the empty rows, we need to pre-fill this array.
- const lengths = new Array( table.childCount ).fill( 0 );
- for ( const { row } of new TableWalker( table, { includeAllSlots: true } ) ) {
- lengths[ row ]++;
- }
- return lengths;
- }
- // Checks if the differ entry for an attribute change is one of the table's attributes.
- //
- // @param entry
- // @returns {Boolean}
- function isTableAttributeEntry( entry ) {
- const isAttributeType = entry.type === 'attribute';
- const key = entry.attributeKey;
- return isAttributeType && ( key === 'headingRows' || key === 'colspan' || key === 'rowspan' );
- }
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