Files
markdig/src/Markdig/Extensions/Tables/GridTableParser.cs

382 lines
13 KiB
C#

// Copyright (c) Alexandre Mutel. All rights reserved.
// This file is licensed under the BSD-Clause 2 license.
// See the license.txt file in the project root for more information.
using Markdig.Helpers;
using Markdig.Parsers;
using Markdig.Syntax;
using System.Linq;
namespace Markdig.Extensions.Tables;
public class GridTableParser : BlockParser
{
public GridTableParser()
{
OpeningCharacters = ['+'];
}
public override BlockState TryOpen(BlockProcessor processor)
{
// A grid table cannot start more than an indent
if (processor.IsCodeIndent)
{
return BlockState.None;
}
var line = processor.Line;
GridTableState? tableState = null;
// Match the first row that should be of the minimal form: +---------------
var c = line.CurrentChar;
var lineStart = line.Start;
while (c == '+')
{
var columnStart = line.Start;
line.SkipChar();
line.TrimStart();
// if we have reached the end of the line, exit
c = line.CurrentChar;
if (c == 0)
{
break;
}
// Parse a column alignment
if (!TableHelper.ParseColumnHeader(ref line, '-', out TableColumnAlign? columnAlign, out _))
{
return BlockState.None;
}
tableState ??= new GridTableState(start: processor.Start, expectRow: true);
tableState.AddColumn(columnStart - lineStart, line.Start - lineStart, columnAlign);
c = line.CurrentChar;
}
if (c != 0 || tableState is null)
{
return BlockState.None;
}
// Store the line (if we need later to build a ParagraphBlock because the GridTable was in fact invalid)
tableState.AddLine(ref processor.Line);
var table = new Table(this)
{
Line = processor.LineIndex,
Column = processor.Column,
Span = { Start = lineStart }
};
table.SetData(typeof(GridTableState), tableState);
// Calculate the total width of all columns
int totalWidth = 0;
foreach (var columnSlice in tableState.ColumnSlices!)
{
totalWidth += columnSlice.End - columnSlice.Start - 1;
}
// Store the column width and alignment
foreach (var columnSlice in tableState.ColumnSlices)
{
var columnDefinition = new TableColumnDefinition
{
// Column width proportional to the total width
Width = (float)(columnSlice.End - columnSlice.Start - 1) * 100.0f / totalWidth,
Alignment = columnSlice.Align
};
table.ColumnDefinitions.Add(columnDefinition);
}
processor.NewBlocks.Push(table);
return BlockState.ContinueDiscard;
}
public override BlockState TryContinue(BlockProcessor processor, Block block)
{
var gridTable = (Table)block;
var tableState = (GridTableState)block.GetData(typeof(GridTableState))!;
tableState.AddLine(ref processor.Line);
if (processor.CurrentChar == '+')
{
gridTable.UpdateSpanEnd(processor.Line.End);
return HandleNewRow(processor, tableState, gridTable);
}
if (processor.CurrentChar == '|')
{
gridTable.UpdateSpanEnd(processor.Line.End);
return HandleContents(processor, tableState, gridTable);
}
TerminateCurrentRow(processor, tableState, gridTable, true);
// If the table is not valid we need to remove the grid table,
// and create a ParagraphBlock with the slices
if (!gridTable.IsValid())
{
Undo(processor, tableState, gridTable);
}
return BlockState.Break;
}
private BlockState HandleNewRow(BlockProcessor processor, GridTableState tableState, Table gridTable)
{
var columns = tableState.ColumnSlices!;
SetRowSpanState(columns, processor.Line, out bool isHeaderRow, out bool hasRowSpan);
SetColumnSpanState(columns, processor.Line);
TerminateCurrentRow(processor, tableState, gridTable, false);
if (isHeaderRow)
{
for (int i = 0; i < gridTable.Count; i++)
{
var row = (TableRow)gridTable[i];
row.IsHeader = true;
}
}
tableState.StartRowGroup = gridTable.Count;
if (hasRowSpan)
{
HandleContents(processor, tableState, gridTable);
}
return BlockState.ContinueDiscard;
}
private static void SetRowSpanState(List<GridTableState.ColumnSlice> columns, StringSlice line, out bool isHeaderRow, out bool hasRowSpan)
{
var lineStart = line.Start;
var lineEnd = line.End;
isHeaderRow = line.PeekChar() == '=' || line.PeekChar(2) == '=';
hasRowSpan = false;
foreach (var columnSlice in columns)
{
if (columnSlice.CurrentCell != null)
{
line.Start = lineStart + columnSlice.Start + 1;
line.End = Math.Min(lineStart + columnSlice.End - 1, lineEnd);
line.Trim();
if (line.IsEmptyOrWhitespace() || !IsRowSeparator(line))
{
hasRowSpan = true;
columnSlice.CurrentCell.RowSpan++;
columnSlice.CurrentCell.AllowClose = false;
}
else
{
columnSlice.CurrentCell.AllowClose = true;
}
}
}
}
private static bool IsRowSeparator(StringSlice slice)
{
char c = slice.CurrentChar;
do
{
if (c != '-' && c != '=' && c != ':')
{
return c == '\0';
}
c = slice.NextChar();
}
while (true);
}
private static void TerminateCurrentRow(BlockProcessor processor, GridTableState tableState, Table gridTable, bool isLastRow)
{
var columns = tableState.ColumnSlices;
TableRow? currentRow = null;
for (int i = 0; i < columns!.Count; i++)
{
var columnSlice = columns[i];
if (columnSlice.CurrentCell != null)
{
if (currentRow == null)
{
TableCell firstCell = columns.First(c => c.CurrentCell != null).CurrentCell!;
TableCell lastCell = columns.Last(c => c.CurrentCell != null).CurrentCell!;
currentRow ??= new TableRow()
{
Span = new SourceSpan(firstCell.Span.Start, lastCell.Span.End),
Line = firstCell.Line
};
}
// If this cell does not already belong to a row
if (columnSlice.CurrentCell.Parent is null)
{
currentRow.Add(columnSlice.CurrentCell);
}
// If the cell is not going to span through to the next row
if (columnSlice.CurrentCell.AllowClose)
{
columnSlice.BlockProcessor!.Close(columnSlice.CurrentCell);
}
}
// Renew the block parser processor (or reset it for the last row)
if (columnSlice.BlockProcessor != null && (columnSlice.CurrentCell is null || columnSlice.CurrentCell.AllowClose))
{
columnSlice.BlockProcessor.ReleaseChild();
columnSlice.BlockProcessor = isLastRow ? null : processor.CreateChild();
}
// Create or erase the cell
if (isLastRow || columnSlice.CurrentColumnSpan == 0 || (columnSlice.CurrentCell != null && columnSlice.CurrentCell.AllowClose))
{
// We don't need the cell anymore if we have a last row
// Or the cell has a columnspan == 0
// And the cell does not have to be kept open to span rows
columnSlice.CurrentCell = null;
}
}
if (currentRow is { Count: > 0 })
{
gridTable.Add(currentRow);
}
}
private BlockState HandleContents(BlockProcessor processor, GridTableState tableState, Table gridTable)
{
var isRowLine = processor.CurrentChar == '+';
var columns = tableState.ColumnSlices!;
var line = processor.Line;
SetColumnSpanState(columns, line);
if (!isRowLine && !CanContinueRow(columns))
{
TerminateCurrentRow(processor, tableState, gridTable, false);
}
for (int i = 0; i < columns.Count;)
{
var columnSlice = columns[i];
var nextColumnIndex = i + columnSlice.CurrentColumnSpan;
// If the span is 0, we exit
if (nextColumnIndex == i)
{
break;
}
var nextColumn = nextColumnIndex < columns.Count ? columns[nextColumnIndex] : null;
var sliceForCell = line;
sliceForCell.Start = line.Start + columnSlice.Start + 1;
if (nextColumn != null)
{
sliceForCell.End = line.Start + nextColumn.Start - 1;
}
else
{
var columnEnd = columns[columns.Count - 1].End;
var columnEndChar = line.PeekCharExtra(columnEnd);
// If there is a `|` (or a `+` in the case that we are dealing with a row line
// with spanned contents) exactly at the expected end of the table row, we cut the line
// otherwise we allow to have the last cell of a row to be open for longer cell content
if (columnEndChar == '|' || (isRowLine && columnEndChar == '+'))
{
sliceForCell.End = line.Start + columnEnd - 1;
}
else if (line.PeekCharExtra(line.End - line.Start) == '|')
{
sliceForCell.End = line.End - 1;
}
}
sliceForCell.TrimEnd();
if (!isRowLine || !IsRowSeparator(sliceForCell))
{
if (columnSlice.CurrentCell is null)
{
columnSlice.CurrentCell = new TableCell(this)
{
ColumnSpan = columnSlice.CurrentColumnSpan,
ColumnIndex = i,
Column = columnSlice.Start,
Line = processor.LineIndex,
Span = new SourceSpan(line.Start + columnSlice.Start, line.Start + columnSlice.End)
};
columnSlice.BlockProcessor ??= processor.CreateChild();
// Ensure that the BlockParser is aware that the TableCell is the top-level container
columnSlice.BlockProcessor.Open(columnSlice.CurrentCell);
}
// Process the content of the cell
columnSlice.BlockProcessor!.LineIndex = processor.LineIndex;
columnSlice.BlockProcessor.ProcessLine(sliceForCell, sliceForCell.Start - line.Start);
}
// Go to next column
i = nextColumnIndex;
}
return BlockState.ContinueDiscard;
}
private static void SetColumnSpanState(List<GridTableState.ColumnSlice> columns, StringSlice line)
{
foreach (var columnSlice in columns)
{
columnSlice.PreviousColumnSpan = columnSlice.CurrentColumnSpan;
columnSlice.CurrentColumnSpan = 0;
}
// | ------------- | ------------ | ---------------------------------------- |
// Calculate the colspan for the new row
int columnIndex = -1;
for (int i = 0; i < columns.Count; i++)
{
var columnSlice = columns[i];
var peek = line.PeekChar(columnSlice.Start);
if (peek == '|' || peek == '+')
{
columnIndex = i;
}
if (columnIndex >= 0)
{
columns[columnIndex].CurrentColumnSpan++;
}
}
}
private static bool CanContinueRow(List<GridTableState.ColumnSlice> columns)
{
foreach (var columnSlice in columns)
{
if (columnSlice.PreviousColumnSpan != columnSlice.CurrentColumnSpan)
{
return false;
}
}
return true;
}
private static void Undo(BlockProcessor processor, GridTableState tableState, Table gridTable)
{
var parser = processor.Parsers.FindExact<ParagraphBlockParser>();
// Discard the grid table
var parent = gridTable.Parent!;
processor.Discard(gridTable);
var paragraphBlock = new ParagraphBlock(parser)
{
Lines = tableState.Lines,
};
parent.Add(paragraphBlock);
processor.Open(paragraphBlock);
}
public override bool Close(BlockProcessor processor, Block block)
{
// Work only on Table, not on TableCell
var gridTable = block as Table;
if (gridTable != null)
{
var tableState = (GridTableState)block.GetData(typeof(GridTableState))!;
TerminateCurrentRow(processor, tableState, gridTable, true);
if (!gridTable.IsValid())
{
Undo(processor, tableState, gridTable);
}
}
return true;
}
}