fix(CtElementImpl#toString): fix toString for SniperPrinter (#3147)

src/main/java/spoon/reflect/visitor/DefaultJavaPrettyPrinter.java

@@ -5,6 +5,7 @@
  */
 package spoon.reflect.visitor;
 
+import org.apache.log4j.Logger;
 import spoon.SpoonException;
 import spoon.compiler.Environment;
 import spoon.experimental.CtUnresolvedImport;
@@ -234,6 +235,37 @@ public DefaultJavaPrettyPrinter setLineSeparator(String lineSeparator) {
 		return this;
 	}
 
+
+	protected static final Logger LOGGER = Logger.getLogger(DefaultJavaPrettyPrinter.class);
+	public static final String ERROR_MESSAGE_TO_STRING = "Error in printing the node. One parent isn't initialized!";
+	/**
+	 * Prints an element. This method shall be called by the toString() method of an element.
+	 * It is responsible for any initialization required to print an arbitrary element.
+	 * @param element
+	 * @return A string containing the pretty printed element (and descendants).
+	 */
+	public String printElement(CtElement element) {
+
+		String errorMessage = "";
+		try {
+			// now that pretty-printing can change the model, we only do it on a clone
+			CtElement clone = element.clone();
+
+			// required: in DJPP some decisions are taken based on the content of the parent
+			if (element.isParentInitialized()) {
+				clone.setParent(element.getParent());
+			}
+			applyPreProcessors(clone);
+			scan(clone);
+		} catch (ParentNotInitializedException ignore) {
+			LOGGER.error(ERROR_MESSAGE_TO_STRING, ignore);
+			errorMessage = ERROR_MESSAGE_TO_STRING;
+		}
+		// in line-preservation mode, newlines are added at the beginning to matches the lines
+		// removing them from the toString() representation
+		return toString().replaceFirst("^\\s+", "") + errorMessage;
+	}
+
 	/**
 	 * Enters an expression.
 	 */
@@ -1956,7 +1988,7 @@ public String getResult() {
 	public void reset() {
 		printer.reset();
 		context = new PrintingContext();
-		}
+	}
 
 
 	/**

src/main/java/spoon/reflect/visitor/PrettyPrinter.java

@@ -42,6 +42,14 @@ public interface PrettyPrinter {
 	 */
 	String printTypes(CtType<?>... type);
 
+	/**
+	 * Prints an element. This method shall be called by the toString() method of an element.
+	 * It is responsible for any initialization required to print an arbitrary element.
+	 * @param element
+	 * @return A string containing the pretty printed element (and descendants).
+	 */
+	String printElement(CtElement element);
+
 	/**
 	 * Gets the contents of the compilation unit.
 	 */

src/main/java/spoon/support/reflect/declaration/CtElementImpl.java

@@ -292,26 +292,7 @@ public String toStringDebug() {
 	public String toString() {
 		DefaultJavaPrettyPrinter printer = (DefaultJavaPrettyPrinter) getFactory().getEnvironment().createPrettyPrinter();
 
-		String errorMessage = "";
-		try {
-			// now that pretty-printing can change the model, we only do it on a clone
-			CtElement clone = this.clone();
-
-			// required: in DJPP some decisions are taken based on the content of the parent
-			if (this.isParentInitialized()) {
-				clone.setParent(this.getParent());
-			}
-
-			printer.applyPreProcessors(clone);
-
-			printer.scan(clone);
-		} catch (ParentNotInitializedException ignore) {
-			LOGGER.error(ERROR_MESSAGE_TO_STRING, ignore);
-			errorMessage = ERROR_MESSAGE_TO_STRING;
-		}
-		// in line-preservation mode, newlines are added at the beginning to matches the lines
-		// removing them from the toString() representation
-		return printer.toString().replaceFirst("^\\s+", "") + errorMessage;
+		return printer.printElement(this);
 	}
 
 	@Override

src/main/java/spoon/support/sniper/SniperJavaPrettyPrinter.java

@@ -13,6 +13,8 @@
 import spoon.SpoonException;
 import spoon.compiler.Environment;
 import spoon.reflect.code.CtComment;
+import spoon.reflect.cu.CompilationUnit;
+import spoon.reflect.cu.position.NoSourcePosition;
 import spoon.reflect.declaration.CtCompilationUnit;
 import spoon.reflect.declaration.CtElement;
 import spoon.reflect.path.CtRole;
@@ -176,8 +178,65 @@ public void printSourceFragment(SourceFragment fragment, Boolean isModified) {
 	}
 
 
+
+	private static boolean hasImplicitAncestor(CtElement el) {
+		if (el == null) {
+			return false;
+		}
+		if (el == el.getFactory().getModel().getRootPackage()) {
+			return false;
+		} else if (el.isImplicit()) {
+			return true;
+		} else {
+			return hasImplicitAncestor(el.getParent());
+		}
+	}
+
+	/**
+	 * SniperPrettyPrinter does not apply preprocessor to a CtElement when calling toString()
+	 * @param element
+	 * @return
+	 */
+	@Override
+	public String printElement(CtElement element) {
+		if (element != null && !hasImplicitAncestor(element)) {
+			CompilationUnit compilationUnit = element.getPosition().getCompilationUnit();
+			if (compilationUnit != null
+					&& !(compilationUnit instanceof NoSourcePosition.NullCompilationUnit)) {
+
+				//use line separator of origin source file
+				setLineSeparator(detectLineSeparator(compilationUnit.getOriginalSourceCode()));
+
+				CtRole role = getRoleInCompilationUnit(element);
+				ElementSourceFragment esf = element.getOriginalSourceFragment();
+
+				runInContext(
+					new SourceFragmentContextList(mutableTokenWriter,
+						element,
+						Collections.singletonList(esf),
+						new ChangeResolver(getChangeCollector(), element)),
+					() -> onPrintEvent(new ElementPrinterEvent(role, element) {
+						@Override
+						public void print(Boolean muted) {
+							superScanInContext(element, SourceFragmentContextPrettyPrint.INSTANCE, muted);
+						}
+
+						@Override
+						public void printSourceFragment(SourceFragment fragment, Boolean isModified) {
+							scanInternal(role, element, fragment, isModified);
+						}
+					})
+				);
+			}
+		}
+
+		return toString().replaceFirst("^\\s+", "");
+	}
+
+
 	/**
 	 * Called whenever {@link DefaultJavaPrettyPrinter} scans/prints an element
+	 * Warning: DO not call on a cloned element. Use scanClone instead.
 	 */
 	@Override
 	public SniperJavaPrettyPrinter scan(CtElement element) {

src/main/java/spoon/support/visitor/equals/CloneHelper.java

@@ -95,7 +95,7 @@ public <T extends CtElement> Map<String, T> clone(Map<String, T> elements) {
 	}
 
 	/**
-	 * clones a element and adds it's clone as value into targetCollection
+	 * clones an element and adds it's clone as value into targetCollection
 	 * @param targetCollection - the collection which will receive a clone of element
 	 * @param element to be cloned element
 	 */

src/test/java/spoon/test/prettyprinter/TestSniperPrinter.java

@@ -18,20 +18,31 @@
 
 import org.junit.Test;
 import spoon.Launcher;
+import spoon.SpoonException;
+import spoon.compiler.Environment;
+import spoon.processing.AbstractProcessor;
 import spoon.processing.Processor;
+import spoon.processing.ProcessorProperties;
+import spoon.processing.TraversalStrategy;
+import spoon.reflect.CtModel;
 import spoon.reflect.code.CtStatement;
 import spoon.reflect.declaration.CtClass;
-import spoon.reflect.declaration.CtCompilationUnit;
 import spoon.reflect.declaration.CtElement;
 import spoon.reflect.declaration.CtField;
 import spoon.reflect.declaration.CtMethod;
+import spoon.reflect.declaration.CtModule;
+import spoon.reflect.declaration.CtPackage;
 import spoon.reflect.declaration.CtType;
 import spoon.reflect.declaration.ModifierKind;
 import spoon.reflect.factory.Factory;
+import spoon.reflect.reference.CtPackageReference;
 import spoon.reflect.reference.CtTypeReference;
+import spoon.reflect.visitor.CtScanner;
 import spoon.reflect.visitor.ImportCleaner;
 import spoon.reflect.visitor.ImportConflictDetector;
+import spoon.reflect.visitor.filter.TypeFilter;
 import spoon.support.modelobs.ChangeCollector;
+import spoon.support.modelobs.SourceFragmentCreator;
 import spoon.support.sniper.SniperJavaPrettyPrinter;
 import spoon.test.prettyprinter.testclasses.ToBeChanged;
 
@@ -40,14 +51,23 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.UnsupportedEncodingException;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Paths;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Set;
 import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 public class TestSniperPrinter {
 
@@ -263,4 +283,51 @@ private String sourceWithoutImports(String source) {
 		}
 		return source.substring(lastImportEnd).trim();
 	}
+
+	private static String fileAsString(String path, Charset encoding)
+			throws IOException
+	{
+		byte[] encoded = Files.readAllBytes(Paths.get(path));
+		return new String(encoded, encoding);
+	}
+
+	public void testToStringWithSniperPrinter(String inputSourcePath) throws Exception {
+
+		final Launcher launcher = new Launcher();
+		launcher.addInputResource(inputSourcePath);
+		String originalContent = fileAsString(inputSourcePath, StandardCharsets.UTF_8).replace("\t","");
+		CtModel model = launcher.buildModel();
+
+		new SourceFragmentCreator().attachTo(launcher.getFactory().getEnvironment());
+
+		launcher.getEnvironment().setPrettyPrinterCreator(
+				() -> {
+					SniperJavaPrettyPrinter sp = new SniperJavaPrettyPrinter(launcher.getEnvironment());
+					sp.setIgnoreImplicit(true);
+					return sp;
+				}
+		);
+		List<CtElement> ops = model.getElements(new TypeFilter<>(CtElement.class));
+
+
+		ops.stream()
+				.filter(el -> !(el instanceof spoon.reflect.CtModelImpl.CtRootPackage) &&
+						!(el instanceof spoon.reflect.factory.ModuleFactory.CtUnnamedModule)
+				).forEach(el -> {
+			try {
+				//Contract, calling toString on unmodified AST elements should draw only from original.
+				assertTrue("ToString() on element (" + el.getClass().getName() + ") =  \"" + el + "\" is not in original content",
+						originalContent.contains(el.toString().replace("\t","")));
+			} catch (UnsupportedOperationException | SpoonException e) {
+				//Printer should not throw exception on printable element. (Unless there is a bug in the printer...)
+				fail("ToString() on Element (" + el.getClass().getName() + "): at " + el.getPath() + " lead to an exception: " + e);
+			}
+		});
+	}
+
+	@Test
+	public void testToStringWithSniperOnElementScan() throws Exception {
+		testToStringWithSniperPrinter("src/test/java/spoon/test/prettyprinter/testclasses/ElementScan.java");
+	}
+
 }

src/test/java/spoon/test/prettyprinter/testclasses/ElementScan.java

@@ -0,0 +1,23 @@
+package spoon.test.prettyprinter.testclasses;
+
+/**
+ * Copyright (C) 2006-2019 INRIA and contributors
+ *
+ * Spoon is available either under the terms of the MIT License (see LICENSE-MIT.txt) of the Cecill-C License (see LICENSE-CECILL-C.txt). You as the user are entitled to choose the terms under which to adopt Spoon.
+ */
+import spoon.reflect.cu.SourcePositionHolder;
+import spoon.reflect.declaration.CtElement;
+import spoon.reflect.visitor.EarlyTerminatingScanner;
+
+public class ElementScan {
+
+	public void isElementExists(SourcePositionHolder element) {
+		EarlyTerminatingScanner<Boolean> scanner = new EarlyTerminatingScanner<Boolean>() {
+			@Override
+			protected void enter(CtElement e) {
+				if (element == e) {
+				}
+			}
+		};
+	}
+}