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Keep comments in .flattened-pom.xml mojohaus#270
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ca-stefan-cordes authored and slawekjaranowski committed Aug 15, 2022
1 parent 13c9a58 commit a940cb1
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32 changes: 27 additions & 5 deletions src/main/java/org/codehaus/mojo/flatten/FlattenMojo.java
Original file line number Diff line number Diff line change
Expand Up @@ -369,6 +369,16 @@ public class FlattenMojo
@Parameter( defaultValue = "${session}", readonly = true, required = true )
private MavenSession session;

/**
* The core maven model readers/writers are discarding the comments of the pom.xml.
* By setting keepCommentsInPom to true the current comments are moved to the flattened pom.xml.
* Default value is false (= not re-adding comments).
*
* @since 1.3.0
*/
@Parameter( property = "flatten.dependency.keepComments", required = false , defaultValue = "false")
private boolean keepCommentsInPom;

@Component
private DependencyResolver dependencyResolver;

Expand Down Expand Up @@ -399,19 +409,25 @@ public void execute()
getLog().info( "Generating flattened POM of project " + this.project.getId() + "..." );

File originalPomFile = this.project.getFile();
KeepCommentsInPom commentsOfOriginalPomFile = null;
if (keepCommentsInPom) {
commentsOfOriginalPomFile = KeepCommentsInPom.create(getLog(), originalPomFile);
}
Model flattenedPom = createFlattenedPom( originalPomFile );
String headerComment = extractHeaderComment( originalPomFile );

File flattenedPomFile = getFlattenedPomFile();
writePom( flattenedPom, flattenedPomFile, headerComment );
writePom( flattenedPom, flattenedPomFile, headerComment , commentsOfOriginalPomFile);

if ( isUpdatePomFile() )
{
this.project.setPomFile( flattenedPomFile );
}
}

/**


/**
* This method extracts the XML header comment if available.
*
* @param xmlFile is the XML {@link File} to parse.
Expand Down Expand Up @@ -447,7 +463,7 @@ protected String extractHeaderComment( File xmlFile )
* before root tag). May be <code>null</code> if not present and to be omitted in target POM.
* @throws MojoExecutionException if the operation failed (e.g. due to an {@link IOException}).
*/
protected void writePom( Model pom, File pomFile, String headerComment )
protected void writePom( Model pom, File pomFile, String headerComment, KeepCommentsInPom anOriginalCommentsPath )
throws MojoExecutionException
{

Expand Down Expand Up @@ -485,10 +501,16 @@ protected void writePom( Model pom, File pomFile, String headerComment )
getLog().warn( "POM XML post-processing failed: no project tag found!" );
}
}
writeStringToFile( buffer.toString(), pomFile, pom.getModelEncoding() );
String xmlString;
if (anOriginalCommentsPath == null) {
xmlString = buffer.toString();
} else {
xmlString = anOriginalCommentsPath.restoreOriginalComments(buffer.toString(), pom.getModelEncoding());
}
writeStringToFile( xmlString, pomFile, pom.getModelEncoding() );
}

/**
/**
* Writes the given <code>data</code> to the given <code>file</code> using the specified <code>encoding</code>.
*
* @param data is the {@link String} to write.
Expand Down
269 changes: 269 additions & 0 deletions src/main/java/org/codehaus/mojo/flatten/KeepCommentsInPom.java
Original file line number Diff line number Diff line change
@@ -0,0 +1,269 @@
package org.codehaus.mojo.flatten;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.function.BiConsumer;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugin.logging.Log;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.bootstrap.DOMImplementationRegistry;
import org.w3c.dom.ls.DOMImplementationLS;
import org.w3c.dom.ls.LSOutput;
import org.w3c.dom.ls.LSSerializer;
import org.xml.sax.SAXException;

/**
* Helper class to keep the comments how they have been in the original pom.xml While reading with
* {@link org.apache.maven.model.io.xpp3.MavenXpp3Writer} the comments are not placed into the
* {@link org.apache.maven.model.Model} and so {@link org.apache.maven.model.io.xpp3.MavenXpp3Writer} is not able to
* re-write those comments.
*
* Workaround (maybe until core is fixed) is to remember all the comments and restore them after MavenXpp3Writer has
* created the new flattened pom.xml.
*
* Current restriction on non-unique child nodes is that this class finds the node back due to the position in the file,
* that may lead to mis-re-added comments e.g. on multiple added dependencies (but for e.g. resolveCiFriendliesOnly the
* nodes keep stable)
*
*/
class KeepCommentsInPom
{

/**
* Create an instance with collected current comments of the passed pom.xml file.
*/
static KeepCommentsInPom create(Log aLog, File aOriginalPomFile) throws MojoExecutionException
{
KeepCommentsInPom tempKeepCommentsInPom = new KeepCommentsInPom();
tempKeepCommentsInPom.setLog(aLog);
tempKeepCommentsInPom.loadComments(aOriginalPomFile);
return tempKeepCommentsInPom;
}

private Log log;

/**
* The unique path list for an original node (the comments are stored via the referenced previousSibling)
*/
private Map<String, Node> commentsPaths;

/**
*
*/
KeepCommentsInPom()
{
super();
}

/**
* load all current comments and text fragments from xml file
*
* @param anOriginalPomFile the pom.xml
*/
private void loadComments(File anOriginalPomFile) throws MojoExecutionException
{
commentsPaths = new HashMap<>();
DocumentBuilderFactory tempDBF = DocumentBuilderFactory.newInstance();
DocumentBuilder tempDB;
try
{
tempDB = tempDBF.newDocumentBuilder();
Document tempPom = tempDB.parse(anOriginalPomFile);
Node tempNode = tempPom.getDocumentElement();
walkOverNodes(tempNode, ".", (node, nodePath) ->
{
// collectNodesByPathNames
commentsPaths.put(nodePath, node);
});
} catch (ParserConfigurationException | SAXException | IOException e)
{
throw new MojoExecutionException("Cannot load comments from " + anOriginalPomFile, e);
}
}

/**
* Walk over the pom hierarchy of the Document.
*
* @param Node the current Node
* @param String the unique path in the parent
* @param aConsumer Function to be called with the toBeCollected/found node.
*/
private void walkOverNodes(Node aNode, String aParentPath, BiConsumer<Node, String> aConsumer)
{
String tempNodeName = aNode.getNodeName();
if (log.isDebugEnabled())
{
log.debug("walkOverNodes: aParentPath=" + aParentPath + " tempNodeName=" + tempNodeName);
}
String tempNodePath = aParentPath + "\t" + tempNodeName;
aConsumer.accept(aNode, tempNodePath);
NodeList tempChilds = aNode.getChildNodes();
// Copy the childs as aConsumer may change the node sequence (add a comment)
List<Node> tempCopiedChilds = new ArrayList<>();
Map<String, Integer> tempChildWithSameName = new HashMap<>();
for (int i = 0; i < tempChilds.getLength(); i++)
{
Node tempItem = tempChilds.item(i);
if (tempItem.getNodeType() != Node.TEXT_NODE && tempItem.getNodeType() != Node.COMMENT_NODE)
{
// Take real nodes to find them back by number
String tempChildNodeName = tempItem.getNodeName();
Integer tempChildWithSameNameCount = tempChildWithSameName.get(tempChildNodeName);
if (tempChildWithSameNameCount == null)
{
tempChildWithSameNameCount = 1;
} else
{
tempChildWithSameNameCount += 1;
}
tempChildWithSameName.put(tempChildNodeName, tempChildWithSameNameCount);
tempCopiedChilds.add(tempItem);
}
}
Map<String, Integer> tempChildWithSameNameCounters = new HashMap<>();
for (int i = 0; i < tempCopiedChilds.size(); i++)
{
Node tempCopiedChild = tempCopiedChilds.get(i);
String tempChildNodeName = tempCopiedChild.getNodeName();
if (tempChildWithSameName.get(tempChildNodeName) > 1)
{
Integer tempChildWithSameNameCounter = tempChildWithSameNameCounters.get(tempChildNodeName);
if (tempChildWithSameNameCounter == null)
{
tempChildWithSameNameCounter = 1;
} else
{
tempChildWithSameNameCounter += 1;
}
tempChildWithSameNameCounters.put(tempChildNodeName, tempChildWithSameNameCounter);
// add a counter to find back the correct node.
walkOverNodes(tempCopiedChild, tempNodePath + "\t" + tempChildWithSameNameCounter, aConsumer);
} else
{
// unique child names
walkOverNodes(tempCopiedChild, tempNodePath, aConsumer);
}
}
}

/**
* @param String the XML written by {@link org.apache.maven.model.io.xpp3.MavenXpp3Writer}
*/
public String restoreOriginalComments(String anXml, String aModelEncoding) throws MojoExecutionException
{
DocumentBuilderFactory tempDBF = DocumentBuilderFactory.newInstance();
DocumentBuilder tempDB;
try
{
tempDB = tempDBF.newDocumentBuilder();
String tempEncoding = aModelEncoding == null ? "UTF-8" : aModelEncoding; // default encoding UTF-8 when
// nothing in pom model.
Document tempPom = tempDB.parse(new ByteArrayInputStream(anXml.getBytes(tempEncoding)));
Node tempNode = tempPom.getDocumentElement();
walkOverNodes(tempNode, ".", (newNode, nodePath) ->
{
Node tempOriginalNode = commentsPaths.get(nodePath);
if (tempOriginalNode != null)
{
String tempOriginalNodeName = tempOriginalNode.getNodeName();
if (tempOriginalNodeName.equals(newNode.getNodeName()))
{
// found matching node
Node tempRefChild = newNode;
Node tempPotentialCommentOrText = tempOriginalNode.getPreviousSibling();
while (tempPotentialCommentOrText != null
&& tempPotentialCommentOrText.getNodeType() == Node.TEXT_NODE)
{
// skip text in the original xml node
tempPotentialCommentOrText = tempPotentialCommentOrText.getPreviousSibling();
}
while (tempPotentialCommentOrText != null
&& tempPotentialCommentOrText.getNodeType() == Node.COMMENT_NODE)
{
// copy the node to be able to call previoussibling for next element
Node tempRefPrevious = tempRefChild.getPreviousSibling();
String tempWhitespaceTextBeforeRefNode = null;
if (tempRefPrevious != null && tempRefPrevious.getNodeType() == Node.TEXT_NODE)
{
tempWhitespaceTextBeforeRefNode = tempRefPrevious.getNodeValue();
}
Node tempNewComment;
tempNewComment = tempPom.createComment(tempPotentialCommentOrText.getNodeValue());
tempRefChild.getParentNode().insertBefore(tempNewComment, tempRefChild);
// copy the whitespaces between comment and refNode
if (tempWhitespaceTextBeforeRefNode != null)
{
tempRefChild.getParentNode().insertBefore(
tempPom.createTextNode(tempWhitespaceTextBeforeRefNode), tempRefChild);
}

tempRefChild = tempNewComment;

tempPotentialCommentOrText = tempPotentialCommentOrText.getPreviousSibling();
while (tempPotentialCommentOrText != null
&& tempPotentialCommentOrText.getNodeType() == Node.TEXT_NODE)
{
// skip text in the original xml node
tempPotentialCommentOrText = tempPotentialCommentOrText.getPreviousSibling();
}
}
}
}
});
return writeDocumentToString(tempPom);
} catch (ParserConfigurationException | SAXException | IOException | ClassNotFoundException
| InstantiationException | IllegalAccessException | ClassCastException e)
{
throw new MojoExecutionException("Cannot add comments", e);
}
}

/**
* Use an LSSerializer to keep whitespaces added by MavenXpp3Writer
*
* @param Document the pom to write to String.
*/
private String writeDocumentToString(Document aPom)
throws ClassNotFoundException, InstantiationException, IllegalAccessException
{
DOMImplementationRegistry registry = DOMImplementationRegistry.newInstance();
DOMImplementationLS impl = (DOMImplementationLS) registry.getDOMImplementation("LS");
LSOutput output = impl.createLSOutput();
output.setEncoding("UTF-8");
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
output.setByteStream(outStream);
LSSerializer writer = impl.createLSSerializer();
writer.write(aPom, output);
return new String(outStream.toByteArray());
}

/**
* @see #log
*/
public Log getLog()
{
return log;
}

/**
* @see #log
*/
public void setLog(Log aLog)
{
log = aLog;
}

}
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