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ParagraphBlockParser.cs
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ParagraphBlockParser.cs
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// 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.Syntax;
namespace Markdig.Parsers;
/// <summary>
/// Block parser for a <see cref="ParagraphBlock"/>.
/// </summary>
/// <seealso cref="BlockParser" />
public class ParagraphBlockParser : BlockParser
{
public bool ParseSetexHeadings { get; set; } = true;
public override BlockState TryOpen(BlockProcessor processor)
{
if (processor.IsBlankLine)
{
return BlockState.None;
}
// We continue trying to match by default
var paragraph = new ParagraphBlock(this)
{
Column = processor.Column,
Span = new SourceSpan(processor.Line.Start, processor.Line.End),
};
if (processor.TrackTrivia)
{
paragraph.LinesBefore = processor.UseLinesBefore();
paragraph.NewLine = processor.Line.NewLine;
}
processor.NewBlocks.Push(paragraph);
return BlockState.Continue;
}
public override BlockState TryContinue(BlockProcessor processor, Block block)
{
if (processor.IsBlankLine)
{
return BlockState.BreakDiscard;
}
if (!processor.IsCodeIndent && ParseSetexHeadings)
{
return TryParseSetexHeading(processor, block);
}
block.NewLine = processor.Line.NewLine;
block.UpdateSpanEnd(processor.Line.End);
return BlockState.Continue;
}
public override bool Close(BlockProcessor processor, Block block)
{
if (block is ParagraphBlock paragraph)
{
ref var lines = ref paragraph.Lines;
if (processor.TrackTrivia)
{
TryMatchLinkReferenceDefinitionTrivia(ref lines, processor, paragraph);
}
else
{
TryMatchLinkReferenceDefinition(ref lines, processor);
}
int lineCount = lines.Count;
// If Paragraph is empty, we can discard it
if (lineCount == 0)
{
return false;
}
if (!processor.TrackTrivia)
{
for (int i = 0; i < lineCount; i++)
{
lines.Lines[i].Slice.TrimStart();
}
lines.Lines[lineCount - 1].Slice.TrimEnd();
}
}
return true;
}
private BlockState TryParseSetexHeading(BlockProcessor state, Block block)
{
var line = state.Line;
var sourcePosition = line.Start;
int count = 0;
char headingChar = GetHeadingChar(ref line, ref count);
if (headingChar != 0)
{
var paragraph = (ParagraphBlock)block;
bool foundLrd;
if (state.TrackTrivia)
{
foundLrd = TryMatchLinkReferenceDefinitionTrivia(ref paragraph.Lines, state, paragraph);
}
else
{
foundLrd = TryMatchLinkReferenceDefinition(ref paragraph.Lines, state);
}
// If we matched a LinkReferenceDefinition before matching the heading, and the remaining
// lines are empty, we can early exit and remove the paragraph
var parent = block.Parent;
bool isSetTextHeading = !state.IsLazy || paragraph.Column == state.Column || !(parent is QuoteBlock || parent is ListItemBlock);
if (!(foundLrd && paragraph.Lines.Count == 0) && isSetTextHeading)
{
// We discard the paragraph that will be transformed to a heading
state.Discard(paragraph);
while (state.CurrentChar == headingChar)
{
state.NextChar();
}
int level = headingChar == '=' ? 1 : 2;
var heading = new HeadingBlock(this)
{
Column = paragraph.Column,
Span = new SourceSpan(paragraph.Span.Start, line.End),
Level = level,
Lines = paragraph.Lines,
IsSetext = true,
HeaderCharCount = count,
};
if (state.TrackTrivia)
{
heading.LinesBefore = paragraph.LinesBefore;
heading.TriviaBefore = state.UseTrivia(sourcePosition - 1); // remove dashes
heading.TriviaAfter = new StringSlice(state.Line.Text, state.Start, line.End);
heading.NewLine = state.Line.NewLine;
heading.SetextNewline = paragraph.NewLine;
}
else
{
heading.Lines.Trim();
}
// Remove the paragraph as a pending block
state.NewBlocks.Push(heading);
return BlockState.BreakDiscard;
}
}
block.UpdateSpanEnd(state.Line.End);
return BlockState.Continue;
}
private static char GetHeadingChar(ref StringSlice line, ref int count)
{
char headingChar = line.CurrentChar;
if (headingChar == '=' || headingChar == '-')
{
count = line.CountAndSkipChar(headingChar);
while (line.CurrentChar.IsSpaceOrTab())
{
line.NextChar();
}
if (line.IsEmpty)
{
return headingChar;
}
}
return (char)0;
}
private static bool TryMatchLinkReferenceDefinition(ref StringLineGroup lines, BlockProcessor state)
{
bool atLeastOneFound = false;
while (true)
{
// If we have found a LinkReferenceDefinition, we can discard the previous paragraph
var iterator = lines.ToCharIterator();
if (LinkReferenceDefinition.TryParse(ref iterator, out LinkReferenceDefinition? linkReferenceDefinition))
{
state.Document.SetLinkReferenceDefinition(linkReferenceDefinition.Label!, linkReferenceDefinition, true);
atLeastOneFound = true;
// Correct the locations of each field
linkReferenceDefinition.Line = lines.Lines[0].Line;
int startPosition = lines.Lines[0].Slice.Start;
linkReferenceDefinition.Span = linkReferenceDefinition.Span .MoveForward(startPosition);
linkReferenceDefinition.LabelSpan = linkReferenceDefinition.LabelSpan .MoveForward(startPosition);
linkReferenceDefinition.UrlSpan = linkReferenceDefinition.UrlSpan .MoveForward(startPosition);
linkReferenceDefinition.TitleSpan = linkReferenceDefinition.TitleSpan .MoveForward(startPosition);
lines = iterator.Remaining();
}
else
{
break;
}
}
return atLeastOneFound;
}
private static bool TryMatchLinkReferenceDefinitionTrivia(ref StringLineGroup lines, BlockProcessor state, ParagraphBlock paragraph)
{
bool atLeastOneFound = false;
while (true)
{
// If we have found a LinkReferenceDefinition, we can discard the previous paragraph
var iterator = lines.ToCharIterator();
if (LinkReferenceDefinition.TryParseTrivia(
ref iterator,
out LinkReferenceDefinition? lrd,
out SourceSpan triviaBeforeLabel,
out SourceSpan labelWithTrivia,
out SourceSpan triviaBeforeUrl,
out SourceSpan unescapedUrl,
out SourceSpan triviaBeforeTitle,
out SourceSpan unescapedTitle,
out SourceSpan triviaAfterTitle))
{
state.Document.SetLinkReferenceDefinition(lrd.Label!, lrd, false);
lrd.Parent = null; // remove LRDG parent from lrd
atLeastOneFound = true;
// Correct the locations of each field
lrd.Line = lines.Lines[0].Line;
var text = lines.Lines[0].Slice.Text;
int startPosition = lines.Lines[0].Slice.Start;
triviaBeforeLabel = triviaBeforeLabel.MoveForward(startPosition);
labelWithTrivia = labelWithTrivia.MoveForward(startPosition);
triviaBeforeUrl = triviaBeforeUrl.MoveForward(startPosition);
unescapedUrl = unescapedUrl.MoveForward(startPosition);
triviaBeforeTitle = triviaBeforeTitle.MoveForward(startPosition);
unescapedTitle = unescapedTitle.MoveForward(startPosition);
triviaAfterTitle = triviaAfterTitle.MoveForward(startPosition);
lrd.Span = lrd.Span.MoveForward(startPosition);
lrd.TriviaBefore = new StringSlice(text, triviaBeforeLabel.Start, triviaBeforeLabel.End);
lrd.LabelSpan = lrd.LabelSpan.MoveForward(startPosition);
lrd.LabelWithTrivia = new StringSlice(text, labelWithTrivia.Start, labelWithTrivia.End);
lrd.TriviaBeforeUrl = new StringSlice(text, triviaBeforeUrl.Start, triviaBeforeUrl.End);
lrd.UrlSpan = lrd.UrlSpan.MoveForward(startPosition);
lrd.UnescapedUrl = new StringSlice(text, unescapedUrl.Start, unescapedUrl.End);
lrd.TriviaBeforeTitle = new StringSlice(text, triviaBeforeTitle.Start, triviaBeforeTitle.End);
lrd.TitleSpan = lrd.TitleSpan.MoveForward(startPosition);
lrd.UnescapedTitle = new StringSlice(text, unescapedTitle.Start, unescapedTitle.End);
lrd.TriviaAfter = new StringSlice(text, triviaAfterTitle.Start, triviaAfterTitle.End);
lrd.LinesBefore = paragraph.LinesBefore;
state.LinesBefore = paragraph.LinesAfter; // ensure closed paragraph with linesafter placed back on stack
lines = iterator.Remaining();
var index = paragraph.Parent!.IndexOf(paragraph);
paragraph.Parent.Insert(index, lrd);
}
else
{
break;
}
}
return atLeastOneFound;
}
}