--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.jshell/share/classes/jdk/jshell/ExpressionToTypeInfo.java Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,216 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.jshell;
+
+import com.sun.source.tree.ReturnTree;
+import com.sun.source.tree.ClassTree;
+import com.sun.source.tree.CompilationUnitTree;
+import com.sun.source.tree.ConditionalExpressionTree;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MethodTree;
+import com.sun.source.tree.Tree;
+import com.sun.source.util.TreePath;
+import com.sun.source.util.TreePathScanner;
+import com.sun.tools.javac.code.Symtab;
+import com.sun.tools.javac.code.Type;
+import com.sun.tools.javac.code.Types;
+import jdk.jshell.TaskFactory.AnalyzeTask;
+
+/**
+ * Compute information about an expression string, particularly its type name.
+ */
+class ExpressionToTypeInfo {
+
+ private static final String OBJECT_TYPE_NAME = "Object";
+
+ final AnalyzeTask at;
+ final CompilationUnitTree cu;
+ final JShell state;
+ final Symtab syms;
+ final Types types;
+
+ private ExpressionToTypeInfo(AnalyzeTask at, CompilationUnitTree cu, JShell state) {
+ this.at = at;
+ this.cu = cu;
+ this.state = state;
+ this.syms = Symtab.instance(at.context);
+ this.types = Types.instance(at.context);
+ }
+
+ public static class ExpressionInfo {
+ ExpressionTree tree;
+ String typeName;
+ boolean isNonVoid;
+ }
+
+ // return mechanism and other general structure from TreePath.getPath()
+ private static class Result extends Error {
+
+ static final long serialVersionUID = -5942088234594905629L;
+ final TreePath expressionPath;
+
+ Result(TreePath path) {
+ this.expressionPath = path;
+ }
+ }
+
+ private static class PathFinder extends TreePathScanner<TreePath, Boolean> {
+
+ // Optimize out imports etc
+ @Override
+ public TreePath visitCompilationUnit(CompilationUnitTree node, Boolean isTargetContext) {
+ return scan(node.getTypeDecls(), isTargetContext);
+ }
+
+ // Only care about members
+ @Override
+ public TreePath visitClass(ClassTree node, Boolean isTargetContext) {
+ return scan(node.getMembers(), isTargetContext);
+ }
+
+ // Only want the doit method where the code is
+ @Override
+ public TreePath visitMethod(MethodTree node, Boolean isTargetContext) {
+ if (Util.isDoIt(node.getName())) {
+ return scan(node.getBody(), true);
+ } else {
+ return null;
+ }
+ }
+
+ @Override
+ public TreePath visitReturn(ReturnTree node, Boolean isTargetContext) {
+ ExpressionTree tree = node.getExpression();
+ TreePath tp = new TreePath(getCurrentPath(), tree);
+ if (isTargetContext) {
+ throw new Result(tp);
+ } else {
+ return null;
+ }
+ }
+ }
+
+ private Type pathToType(TreePath tp) {
+ return (Type) at.trees().getTypeMirror(tp);
+ }
+
+ private Type pathToType(TreePath tp, Tree tree) {
+ if (tree instanceof ConditionalExpressionTree) {
+ // Conditionals always wind up as Object -- this corrects
+ ConditionalExpressionTree cet = (ConditionalExpressionTree) tree;
+ Type tmt = pathToType(new TreePath(tp, cet.getTrueExpression()));
+ Type tmf = pathToType(new TreePath(tp, cet.getFalseExpression()));
+ if (!tmt.isPrimitive() && !tmf.isPrimitive()) {
+ Type lub = types.lub(tmt, tmf);
+ // System.err.printf("cond ? %s : %s -- lub = %s\n",
+ // varTypeName(tmt), varTypeName(tmf), varTypeName(lub));
+ return lub;
+ }
+ }
+ return pathToType(tp);
+ }
+
+ /**
+ * Entry method: get expression info
+ * @param code the expression as a string
+ * @param state a JShell instance
+ * @return type information
+ */
+ public static ExpressionInfo expressionInfo(String code, JShell state) {
+ if (code == null || code.isEmpty()) {
+ return null;
+ }
+ try {
+ OuterWrap codeWrap = state.outerMap.wrapInTrialClass(Wrap.methodReturnWrap(code));
+ AnalyzeTask at = state.taskFactory.new AnalyzeTask(codeWrap);
+ CompilationUnitTree cu = at.firstCuTree();
+ if (at.hasErrors() || cu == null) {
+ return null;
+ }
+ return new ExpressionToTypeInfo(at, cu, state).typeOfExpression();
+ } catch (Exception ex) {
+ return null;
+ }
+ }
+
+ private ExpressionInfo typeOfExpression() {
+ return treeToInfo(findExpressionPath());
+ }
+
+ private TreePath findExpressionPath() {
+ try {
+ new PathFinder().scan(new TreePath(cu), false);
+ } catch (Result result) {
+ return result.expressionPath;
+ }
+ return null;
+ }
+
+ private ExpressionInfo treeToInfo(TreePath tp) {
+ if (tp != null) {
+ Tree tree = tp.getLeaf();
+ if (tree instanceof ExpressionTree) {
+ ExpressionInfo ei = new ExpressionInfo();
+ ei.tree = (ExpressionTree) tree;
+ Type type = pathToType(tp, tree);
+ if (type != null) {
+ switch (type.getKind()) {
+ case VOID:
+ case NONE:
+ case ERROR:
+ case OTHER:
+ break;
+ case NULL:
+ ei.isNonVoid = true;
+ ei.typeName = OBJECT_TYPE_NAME;
+ break;
+ default: {
+ ei.isNonVoid = true;
+ ei.typeName = varTypeName(type);
+ if (ei.typeName == null) {
+ ei.typeName = OBJECT_TYPE_NAME;
+ }
+ break;
+ }
+ }
+ }
+ return ei;
+ }
+ }
+ return null;
+ }
+
+ private String varTypeName(Type type) {
+ try {
+ TypePrinter tp = new VarTypePrinter(at.messages(),
+ state.maps::fullClassNameAndPackageToClass, syms, types);
+ return tp.toString(type);
+ } catch (Exception ex) {
+ return null;
+ }
+ }
+
+}