com.helger.html.markdown.MarkdownProcessor Maven / Gradle / Ivy
/**
* Copyright (C) 2014-2016 Philip Helger (www.helger.com)
* philip[at]helger[dot]com
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.helger.html.markdown;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.util.Locale;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.annotation.WillClose;
import com.helger.commons.ValueEnforcer;
import com.helger.commons.io.resource.IReadableResource;
import com.helger.commons.io.stream.NonBlockingStringReader;
import com.helger.commons.io.stream.StreamHelper;
import com.helger.commons.string.StringHelper;
/**
* Markdown processor class.
*
* Example usage:
*
*
*
* String result = MarkdownProcessor.process("This is ***TXTMARK***");
*
*
*
* @author René Jeschke <[email protected]>
*/
public class MarkdownProcessor
{
/** The emitter. */
private final Emitter m_aEmitter;
/** The Configuration. */
final MarkdownConfiguration m_aConfig;
/** Extension flag. */
private boolean m_bUseExtensions;
public MarkdownProcessor ()
{
this (MarkdownConfiguration.DEFAULT);
}
/**
* Constructor.
*
* @param aConfig
* The configuration to use. May not be null.
*/
public MarkdownProcessor (@Nonnull final MarkdownConfiguration aConfig)
{
ValueEnforcer.notNull (aConfig, "Config");
m_aConfig = aConfig;
m_bUseExtensions = aConfig.isExtendedProfile ();
m_aEmitter = new Emitter (m_aConfig);
}
/**
* Reads all lines from our reader.
*
* Takes care of markdown link references.
*
*
* @return A Block containing all lines.
* @throws IOException
* If an IO error occurred.
*/
@Nonnull
private Block _readLines (@Nonnull final Reader aReader) throws IOException
{
final Block block = new Block ();
final StringBuilder sb = new StringBuilder (80);
int c = aReader.read ();
LinkRef aLastLinkRef = null;
while (c != -1)
{
sb.setLength (0);
int pos = 0;
boolean eol = false;
while (!eol)
{
switch (c)
{
case -1:
eol = true;
break;
case '\n':
c = aReader.read ();
if (c == '\r')
c = aReader.read ();
eol = true;
break;
case '\r':
c = aReader.read ();
if (c == '\n')
c = aReader.read ();
eol = true;
break;
case '\t':
{
final int np = pos + (4 - (pos & 3));
while (pos < np)
{
sb.append (' ');
pos++;
}
c = aReader.read ();
break;
}
default:
pos++;
sb.append ((char) c);
c = aReader.read ();
break;
}
}
final Line aLine = new Line ();
aLine.m_sValue = sb.toString ();
aLine.init ();
// Check for link definitions
boolean bIsLinkRef = false;
String sID = null, sLink = null, sComment = null;
if (!aLine.m_bIsEmpty && aLine.m_nLeading < 4 && aLine.m_sValue.charAt (aLine.m_nLeading) == '[')
{
aLine.m_nPos = aLine.m_nLeading + 1;
// Read ID up to ']'
sID = aLine.readUntil (']');
// Is ID valid and are there any more characters?
if (sID != null && aLine.m_nPos + 2 < aLine.m_sValue.length ())
{
// Check for ':' ([...]:...)
if (aLine.m_sValue.charAt (aLine.m_nPos + 1) == ':')
{
aLine.m_nPos += 2;
aLine.skipSpaces ();
// Check for link syntax
if (aLine.m_sValue.charAt (aLine.m_nPos) == '<')
{
aLine.m_nPos++;
sLink = aLine.readUntil ('>');
aLine.m_nPos++;
}
else
sLink = aLine.readUntil (' ', '\n');
// Is link valid?
if (sLink != null)
{
// Any non-whitespace characters following?
if (aLine.skipSpaces ())
{
final char ch = aLine.m_sValue.charAt (aLine.m_nPos);
// Read comment
if (ch == '\"' || ch == '\'' || ch == '(')
{
aLine.m_nPos++;
sComment = aLine.readUntil (ch == '(' ? ')' : ch);
// Valid linkRef only if comment is valid
if (sComment != null)
bIsLinkRef = true;
}
}
else
bIsLinkRef = true;
}
}
}
}
// To make compiler happy: add != null checks
if (bIsLinkRef && sID != null && sLink != null)
{
if (sID.toLowerCase (Locale.US).equals ("$profile$"))
{
m_bUseExtensions = sLink.toLowerCase (Locale.US).equals ("extended");
m_aEmitter.setUseExtensions (m_bUseExtensions);
aLastLinkRef = null;
}
else
{
// Store linkRef and skip line
final LinkRef aLinkRef = new LinkRef (sLink,
sComment,
sComment != null && (sLink.length () == 1 && sLink.charAt (0) == '*'));
m_aEmitter.addLinkRef (sID, aLinkRef);
if (sComment == null)
aLastLinkRef = aLinkRef;
}
}
else
{
sComment = null;
// Check for multi-line linkRef
if (!aLine.m_bIsEmpty && aLastLinkRef != null)
{
aLine.m_nPos = aLine.m_nLeading;
final char ch = aLine.m_sValue.charAt (aLine.m_nPos);
if (ch == '\"' || ch == '\'' || ch == '(')
{
aLine.m_nPos++;
sComment = aLine.readUntil (ch == '(' ? ')' : ch);
}
if (sComment != null)
aLastLinkRef.setTitle (sComment);
aLastLinkRef = null;
}
// No multi-line linkRef, store line
if (sComment == null)
{
aLine.m_nPos = 0;
block.appendLine (aLine);
}
}
}
return block;
}
/**
* Initializes a list block by separating it into list item blocks.
*
* @param aRoot
* The Block to process.
*/
private void _initListBlock (@Nonnull final Block aRoot)
{
Line aLine = aRoot.m_aLines;
aLine = aLine.m_aNext;
while (aLine != null)
{
final ELineType t = aLine.getLineType (m_bUseExtensions);
if (t == ELineType.OLIST ||
t == ELineType.ULIST ||
(!aLine.m_bIsEmpty &&
aLine.m_bPrevEmpty &&
aLine.m_nLeading == 0 &&
!(t == ELineType.OLIST || t == ELineType.ULIST)))
{
aRoot.split (aLine.m_aPrevious).m_eType = EBlockType.LIST_ITEM;
}
aLine = aLine.m_aNext;
}
aRoot.split (aRoot.m_aLineTail).m_eType = EBlockType.LIST_ITEM;
}
/**
* Recursively process the given Block.
*
* @param aRoot
* The Block to process.
* @param listMode
* Flag indicating that we're in a list item block.
*/
private void _recurse (@Nonnull final Block aRoot, final boolean listMode)
{
Block aBlock, list;
Line aLine = aRoot.m_aLines;
if (listMode)
{
aRoot.removeListIndent (m_bUseExtensions);
if (m_bUseExtensions && aRoot.m_aLines != null && aRoot.m_aLines.getLineType (m_bUseExtensions) != ELineType.CODE)
{
aRoot.m_sId = aRoot.m_aLines.stripID ();
}
}
while (aLine != null && aLine.m_bIsEmpty)
aLine = aLine.m_aNext;
if (aLine == null)
return;
while (aLine != null)
{
final ELineType eType = aLine.getLineType (m_bUseExtensions);
switch (eType)
{
case OTHER:
{
final boolean bWasEmpty = aLine.m_bPrevEmpty;
while (aLine != null && !aLine.m_bIsEmpty)
{
final ELineType t = aLine.getLineType (m_bUseExtensions);
if ((listMode || m_bUseExtensions) && (t == ELineType.OLIST || t == ELineType.ULIST))
break;
if (m_bUseExtensions && (t == ELineType.CODE || t == ELineType.FENCED_CODE || t == ELineType.PLUGIN))
break;
if (t == ELineType.HEADLINE ||
t == ELineType.HEADLINE1 ||
t == ELineType.HEADLINE2 ||
t == ELineType.HR ||
t == ELineType.BQUOTE ||
t == ELineType.XML ||
t == ELineType.XML_COMMENT)
break;
aLine = aLine.m_aNext;
}
final EBlockType bt;
if (aLine != null && !aLine.m_bIsEmpty)
{
bt = (listMode && !bWasEmpty) ? EBlockType.NONE : EBlockType.PARAGRAPH;
aRoot.split (aLine.m_aPrevious).m_eType = bt;
aRoot.removeLeadingEmptyLines ();
}
else
{
bt = (listMode && (aLine == null || !aLine.m_bIsEmpty) && !bWasEmpty) ? EBlockType.NONE
: EBlockType.PARAGRAPH;
aRoot.split (aLine == null ? aRoot.m_aLineTail : aLine).m_eType = bt;
aRoot.removeLeadingEmptyLines ();
}
aLine = aRoot.m_aLines;
break;
}
case CODE:
while (aLine != null && (aLine.m_bIsEmpty || aLine.m_nLeading > 3))
{
aLine = aLine.m_aNext;
}
aBlock = aRoot.split (aLine != null ? aLine.m_aPrevious : aRoot.m_aLineTail);
aBlock.m_eType = EBlockType.CODE;
aBlock.removeSurroundingEmptyLines ();
break;
case XML:
case XML_COMMENT:
if (aLine.m_aPrevious != null)
{
// FIXME ... this looks wrong
aRoot.split (aLine.m_aPrevious);
}
aRoot.split (aLine.m_aXmlEndLine).m_eType = eType == ELineType.XML ? EBlockType.XML : EBlockType.XML_COMMENT;
aRoot.removeLeadingEmptyLines ();
aLine = aRoot.m_aLines;
break;
case BQUOTE:
while (aLine != null)
{
if (!aLine.m_bIsEmpty &&
aLine.m_bPrevEmpty &&
aLine.m_nLeading == 0 &&
aLine.getLineType (m_bUseExtensions) != ELineType.BQUOTE)
break;
aLine = aLine.m_aNext;
}
aBlock = aRoot.split (aLine != null ? aLine.m_aPrevious : aRoot.m_aLineTail);
aBlock.m_eType = EBlockType.BLOCKQUOTE;
aBlock.removeSurroundingEmptyLines ();
aBlock.removeBlockQuotePrefix ();
_recurse (aBlock, false);
aLine = aRoot.m_aLines;
break;
case HR:
if (aLine.m_aPrevious != null)
{
// FIXME ... this looks wrong
aRoot.split (aLine.m_aPrevious);
}
aRoot.split (aLine).m_eType = EBlockType.RULER;
aRoot.removeLeadingEmptyLines ();
aLine = aRoot.m_aLines;
break;
case FENCED_CODE:
aLine = aLine.m_aNext;
while (aLine != null)
{
if (aLine.getLineType (m_bUseExtensions) == ELineType.FENCED_CODE)
break;
// TODO ... is this really necessary? Maybe add a special
// flag?
aLine = aLine.m_aNext;
}
if (aLine != null)
aLine = aLine.m_aNext;
aBlock = aRoot.split (aLine != null ? aLine.m_aPrevious : aRoot.m_aLineTail);
aBlock.m_eType = EBlockType.FENCED_CODE;
aBlock.m_sMeta = MarkdownHelper.getMetaFromFence (aBlock.m_aLines.m_sValue);
aBlock.m_aLines.setEmpty ();
if (aBlock.m_aLineTail.getLineType (m_bUseExtensions) == ELineType.FENCED_CODE)
aBlock.m_aLineTail.setEmpty ();
aBlock.removeSurroundingEmptyLines ();
break;
case PLUGIN:
aLine = aLine.m_aNext;
while (aLine != null)
{
if (aLine.getLineType (m_bUseExtensions) == ELineType.PLUGIN)
break;
// TODO ... is this really necessary? Maybe add a special
// flag?
aLine = aLine.m_aNext;
}
if (aLine != null)
aLine = aLine.m_aNext;
aBlock = aRoot.split (aLine != null ? aLine.m_aPrevious : aRoot.m_aLineTail);
aBlock.m_eType = EBlockType.PLUGIN;
aBlock.m_sMeta = MarkdownHelper.getMetaFromFence (aBlock.m_aLines.m_sValue);
aBlock.m_aLines.setEmpty ();
if (aBlock.m_aLineTail.getLineType (m_bUseExtensions) == ELineType.PLUGIN)
aBlock.m_aLineTail.setEmpty ();
aBlock.removeSurroundingEmptyLines ();
break;
case HEADLINE:
case HEADLINE1:
case HEADLINE2:
if (aLine.m_aPrevious != null)
aRoot.split (aLine.m_aPrevious);
if (eType != ELineType.HEADLINE)
aLine.m_aNext.setEmpty ();
aBlock = aRoot.split (aLine);
aBlock.m_eType = EBlockType.HEADLINE;
if (eType != ELineType.HEADLINE)
aBlock.m_nHeadlineDepth = eType == ELineType.HEADLINE1 ? 1 : 2;
if (m_bUseExtensions)
aBlock.m_sId = aBlock.m_aLines.stripID ();
aBlock.transfromHeadline ();
aRoot.removeLeadingEmptyLines ();
aLine = aRoot.m_aLines;
break;
case OLIST:
case ULIST:
while (aLine != null)
{
final ELineType e = aLine.getLineType (m_bUseExtensions);
if (!aLine.m_bIsEmpty &&
(aLine.m_bPrevEmpty && aLine.m_nLeading == 0 && !(e == ELineType.OLIST || e == ELineType.ULIST)))
break;
aLine = aLine.m_aNext;
}
list = aRoot.split (aLine != null ? aLine.m_aPrevious : aRoot.m_aLineTail);
list.m_eType = eType == ELineType.OLIST ? EBlockType.ORDERED_LIST : EBlockType.UNORDERED_LIST;
list.m_aLines.m_bPrevEmpty = false;
list.removeSurroundingEmptyLines ();
list.m_aLines.m_bPrevEmpty = false;
_initListBlock (list);
aBlock = list.m_aBlocks;
while (aBlock != null)
{
_recurse (aBlock, true);
aBlock = aBlock.m_aNext;
}
list.expandListParagraphs ();
break;
default:
aLine = aLine.m_aNext;
break;
}
}
}
@Nonnull
public MarkdownProcessingResult process (@Nonnull final IReadableResource aRes) throws IOException
{
ValueEnforcer.notNull (aRes, "Resource");
return process (aRes.getReader (m_aConfig.getEncoding ()));
}
@Nonnull
public MarkdownProcessingResult process (@Nonnull final InputStream aIS) throws IOException
{
ValueEnforcer.notNull (aIS, "InputStream");
return process (StreamHelper.getBuffered (StreamHelper.createReader (aIS, m_aConfig.getEncoding ())));
}
@Nonnull
public MarkdownProcessingResult process (@Nullable final String sText) throws IOException
{
return process (new NonBlockingStringReader (StringHelper.getNotNull (sText)));
}
/**
* Does all the processing.
*
* @param aReader
* The reader to read from
* @return The processing result.
* @throws IOException
* If an IO error occurred.
*/
@Nonnull
public MarkdownProcessingResult process (@Nonnull @WillClose final Reader aReader) throws IOException
{
try
{
final Block aParent = _readLines (aReader);
aParent.removeSurroundingEmptyLines ();
_recurse (aParent, false);
final MarkdownHCStack aOut = new MarkdownHCStack ();
Block aBlock = aParent.m_aBlocks;
while (aBlock != null)
{
m_aEmitter.emit (aOut, aBlock);
aBlock = aBlock.m_aNext;
}
return new MarkdownProcessingResult (aOut);
}
finally
{
StreamHelper.close (aReader);
}
}
}
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