MSHARED-1285 use an up-to-date scanner instead the newscanner

Currently it could happen that the scanner misses changed files (because
they are not part of the delta) or copies files even if they have not
changed (e.g. because the output has changes).

This uses now a different approach, instead of only handling the delta
files, we scan all inputs and compare if they are up-to-date with the
output.

src/main/java/org/apache/maven/shared/filtering/DefaultMavenResourcesFiltering.java

@@ -37,6 +37,7 @@
 import org.apache.commons.io.FilenameUtils;
 import org.apache.commons.io.IOUtils;
 import org.apache.maven.model.Resource;
+import org.codehaus.plexus.util.DirectoryScanner;
 import org.codehaus.plexus.util.Scanner;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -189,20 +190,44 @@ public void filterResources(MavenResourcesExecution mavenResourcesExecution) thr
             // as destination
             // see MNG-1345
             File outputDirectory = mavenResourcesExecution.getOutputDirectory();
-            boolean outputExists = outputDirectory.exists();
-            if (!outputExists && !outputDirectory.mkdirs()) {
+            if (!outputDirectory.mkdirs() && !outputDirectory.exists()) {
                 throw new MavenFilteringException("Cannot create resource output directory: " + outputDirectory);
             }
 
             if (resource.isFiltering()) {
                 isFilteringUsed = true;
             }
 
-            boolean ignoreDelta = !outputExists
-                    || buildContext.hasDelta(mavenResourcesExecution.getFileFilters())
-                    || buildContext.hasDelta(getRelativeOutputDirectory(mavenResourcesExecution));
-            LOGGER.debug("ignoreDelta " + ignoreDelta);
-            Scanner scanner = buildContext.newScanner(resourceDirectory, ignoreDelta);
+            boolean filtersFileChanges = buildContext.hasDelta(mavenResourcesExecution.getFileFilters());
+            Path resourcePath = resourceDirectory.toPath();
+            DirectoryScanner scanner = new DirectoryScanner() {
+                @Override
+                protected boolean isSelected(String name, File file) {
+                    if (filtersFileChanges) {
+                        // if the file filters file has a change we must assume everything is out of
+                        // date
+                        return true;
+                    }
+                    if (file.isFile()) {
+                        try {
+                            File targetFile = getTargetFile(file);
+                            if (targetFile.isFile() && buildContext.isUptodate(targetFile, file)) {
+                                return false;
+                            }
+                        } catch (MavenFilteringException e) {
+                            // can't really do anything than to assume we must copy the file...
+                        }
+                    }
+                    return true;
+                }
+
+                private File getTargetFile(File file) throws MavenFilteringException {
+                    Path relativize = resourcePath.relativize(file.toPath());
+                    return getDestinationFile(
+                            outputDirectory, targetPath, relativize.toString(), mavenResourcesExecution);
+                }
+            };
+            scanner.setBasedir(resourceDirectory);
 
             setupScanner(resource, scanner, mavenResourcesExecution.isAddDefaultExcludes());
 
@@ -276,13 +301,13 @@ public void filterResources(MavenResourcesExecution mavenResourcesExecution) thr
 
             // deal with deleted source files
 
-            scanner = buildContext.newDeleteScanner(resourceDirectory);
+            Scanner deleteScanner = buildContext.newDeleteScanner(resourceDirectory);
 
-            setupScanner(resource, scanner, mavenResourcesExecution.isAddDefaultExcludes());
+            setupScanner(resource, deleteScanner, mavenResourcesExecution.isAddDefaultExcludes());
 
-            scanner.scan();
+            deleteScanner.scan();
 
-            for (String name : scanner.getIncludedFiles()) {
+            for (String name : deleteScanner.getIncludedFiles()) {
                 File destinationFile = getDestinationFile(outputDirectory, targetPath, name, mavenResourcesExecution);
 
                 destinationFile.delete();