JDK14/Java14源码在线阅读
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* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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*
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package jdk.jshell;
import java.util.EnumSet;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.function.Function;
import javax.lang.model.element.Element;
import javax.lang.model.element.ElementKind;
import javax.lang.model.element.VariableElement;
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.IdentifierTree;
import com.sun.source.tree.MethodInvocationTree;
import com.sun.source.tree.MethodTree;
import com.sun.source.tree.NewClassTree;
import com.sun.source.tree.Tree;
import com.sun.source.tree.Tree.Kind;
import com.sun.source.tree.VariableTree;
import com.sun.source.util.TreePath;
import com.sun.source.util.TreePathScanner;
import com.sun.source.util.TreeScanner;
import com.sun.tools.javac.code.Flags;
import com.sun.tools.javac.code.Symbol;
import com.sun.tools.javac.code.Symbol.TypeSymbol;
import com.sun.tools.javac.code.Symtab;
import com.sun.tools.javac.code.Type;
import com.sun.tools.javac.code.Types;
import com.sun.tools.javac.tree.JCTree.JCClassDecl;
import com.sun.tools.javac.tree.TreeInfo;
import com.sun.tools.javac.util.List;
import com.sun.tools.javac.util.ListBuffer;
import jdk.jshell.ExpressionToTypeInfo.ExpressionInfo.AnonymousDescription;
import jdk.jshell.ExpressionToTypeInfo.ExpressionInfo.AnonymousDescription.VariableDesc;
import jdk.jshell.TaskFactory.AnalyzeTask;
import jdk.jshell.TypePrinter.AnonymousTypeKind;
/**
* 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 boolean computeEnhancedInfo;
final boolean enhancedTypesAccessible;
final Symtab syms;
final Types types;
final Map<TypeSymbol, String> anon2Name = new HashMap<>();
private ExpressionToTypeInfo(AnalyzeTask at, CompilationUnitTree cu, JShell state,
boolean computeEnhancedInfo, boolean enhancedTypesAccessible) {
this.at = at;
this.cu = cu;
this.state = state;
this.computeEnhancedInfo = computeEnhancedInfo;
this.enhancedTypesAccessible = enhancedTypesAccessible;
this.syms = Symtab.instance(at.context);
this.types = Types.instance(at.context);
}
public static class ExpressionInfo {
ExpressionTree tree;
boolean isPrimitiveType;
String typeName;
String accessibleTypeName;
/* In result of localVariableTypeForInitializer, the type that should be used
* as a declaration type of the field. This does not include intersection types,
* but does contain references to anonymous types converted to member types.
*/
String declareTypeName;
/* In result of localVariableTypeForInitializer, the apparent/infered type of
* the variable. This includes intersection types, and references to anonymous
* types converted to member types.
*/
String fullTypeName;
/* In result of localVariableTypeForInitializer, the human readable type of
* the variable. This includes intersection types, and human readable descriptions
* of anonymous types.
*/
String displayTypeName;
boolean isNonVoid;
/* In result of localVariableTypeForInitializer, description of important anonymous
* classes.
*/
List<AnonymousDescription> anonymousClasses = List.nil();
/* A description of an anonymous class. */
static class AnonymousDescription {
/* Parameter types of the invoked super constructor.*/
List<String> parameterTypes;
/* Type of the base/enclosing expression, if any.*/
String enclosingInstanceType;
/* The denotable name of the supertype.*/
String superTypeName;
/* The human-readable name of this class.*/
String declareTypeName;
/* If the supertype of this anonymous is a class. */
boolean isClass;
/* Variables captured by this anonymous class*/
List<VariableDesc> capturedVariables;
static class VariableDesc {
String type;
String name;
public VariableDesc(String type, String name) {
this.type = type;
this.name = name;
}
}
}
}
// return mechanism and other general structure from TreePath.getPath()
private static class Result extends Error {
static final long serialVersionUID = -5942088234594905629L;
@SuppressWarnings("serial") // Not statically typed as Serializable
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;
}
}
@Override
public TreePath visitVariable(VariableTree node, Boolean isTargetContext) {
if (isTargetContext) {
throw new Result(getCurrentPath());
} 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;
}
OuterWrap codeWrap = state.outerMap.wrapInTrialClass(Wrap.methodReturnWrap(code));
try {
return state.taskFactory.analyze(codeWrap, at -> {
CompilationUnitTree cu = at.firstCuTree();
if (at.hasErrors() || cu == null) {
return null;
}
return new ExpressionToTypeInfo(at, cu, state, false, false).typeOfExpression();
});
} catch (Exception ex) {
return null;
}
}
/**
* Entry method: get expression info corresponding to a local variable declaration if its type
* has been inferred automatically from the given initializer.
* @param code the initializer as a string
* @param state a JShell instance
* @return type information
*/
public static ExpressionInfo localVariableTypeForInitializer(String code, JShell state, boolean onlyAccessible) {
if (code == null || code.isEmpty()) {
return null;
}
try {
OuterWrap codeWrap = state.outerMap.wrapInTrialClass(Wrap.methodWrap("var $$$ = " + code));
return state.taskFactory.analyze(codeWrap, at -> {
CompilationUnitTree cu = at.firstCuTree();
if (at.hasErrors() || cu == null) {
return null;
}
return new ExpressionToTypeInfo(at, cu, state, true, onlyAccessible)
.typeOfExpression();
});
} catch (Exception ex) {
return null;
}
}
/**List (in a stable order) all NewClassTree instances under {@code from} that should be
* converted to member classes
*
* @param from tree to inspect
* @return NewClassTree instances that should be converted to member classes
*/
public static List<NewClassTree> listAnonymousClassesToConvert(Tree from) {
ListBuffer<NewClassTree> classes = new ListBuffer<>();
new TreeScanner<Void, Void>() {
@Override
public Void visitNewClass(NewClassTree node, Void p) {
if (node.getClassBody() != null) {
classes.append(node);
return null;
}
return super.visitNewClass(node, p);
}
}.scan(from, null);
return classes.toList();
}
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;
}
/**
* A type is accessible if it is public or if it is package-private and is a
* type defined in JShell. Additionally, all its type arguments must be
* accessible
*
* @param type the type to check for accessibility
* @return true if the type name can be referenced
*/
private boolean isAccessible(Type type) {
Symbol.TypeSymbol tsym = type.asElement();
return ((tsym.flags() & Flags.PUBLIC) != 0 ||
((tsym.flags() & Flags.PRIVATE) == 0 &&
Util.isInJShellClass(tsym.flatName().toString()))) &&
type.getTypeArguments().stream()
.allMatch(this::isAccessible);
}
/**
* Return the superclass.
*
* @param type the type
* @return the superclass, or Object on error
*/
private Type supertype(Type type) {
Type sup = types.supertype(type);
if (sup == Type.noType || sup == null) {
return syms.objectType;
}
return sup;
}
/**
* Find an accessible supertype.
*
* @param type the type
* @return the type, if it is accessible, otherwise a superclass or
* interface which is
*/
private List<Type> findAccessibleSupertypes(Type type) {
List<Type> accessible = List.nil();
Type accessibleSuper = syms.objectType;
// Iterate up the superclasses, see if any are accessible
for (Type sup = type; !types.isSameType(sup, syms.objectType); sup = supertype(sup)) {
if (isAccessible(sup)) {
accessible = accessible.prepend(sup);
accessibleSuper = sup;
break;
}
}
// then look through superclasses for accessible interfaces
for (Type sup = type; !types.isSameType(sup, accessibleSuper); sup = supertype(sup)) {
for (Type itf : types.interfaces(sup)) {
if (isAccessible(itf)) {
accessible = accessible.prepend(itf);
}
}
}
if (accessible.isEmpty()) {
// Punt, use Object which is the supertype of everything
accessible = accessible.prepend(syms.objectType);
}
return accessible.reverse();
}
private ExpressionInfo treeToInfo(TreePath tp) {
if (tp != null) {
Tree tree = tp.getLeaf();
boolean isExpression = tree instanceof ExpressionTree;
if (isExpression || tree.getKind() == Kind.VARIABLE) {
ExpressionInfo ei = new ExpressionInfo();
if (isExpression)
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;
ei.accessibleTypeName = OBJECT_TYPE_NAME;
break;
default: {
ei.isNonVoid = true;
ei.isPrimitiveType = type.isPrimitive();
ei.typeName = varTypeName(type, false, AnonymousTypeKind.SUPER);
List<Type> accessibleTypes = findAccessibleSupertypes(type);
ei.accessibleTypeName =
varTypeName(accessibleTypes.head, false, AnonymousTypeKind.SUPER);
if (computeEnhancedInfo) {
Type accessibleType = accessibleTypes.size() == 1 ? accessibleTypes.head
: types.makeIntersectionType(accessibleTypes);
ei.declareTypeName =
varTypeName(accessibleType, false, AnonymousTypeKind.DECLARE);
ei.fullTypeName =
varTypeName(enhancedTypesAccessible ? accessibleType : type,
true, AnonymousTypeKind.DECLARE);
ei.displayTypeName =
varTypeName(type, true, AnonymousTypeKind.DISPLAY);
}
break;
}
}
}
if (tree.getKind() == Tree.Kind.VARIABLE && computeEnhancedInfo) {
Tree init = ((VariableTree) tree).getInitializer();
for (NewClassTree node : listAnonymousClassesToConvert(init)) {
Set<VariableElement> captured = capturedVariables(at,
tp.getCompilationUnit(),
node);
JCClassDecl clazz = (JCClassDecl) node.getClassBody();
MethodInvocationTree superCall =
clazz.getMembers()
.stream()
.map(TreeInfo::firstConstructorCall)
.findAny()
.get();
TreePath superCallPath
= at.trees().
getPath(tp.getCompilationUnit(), superCall.
getMethodSelect());
Type constrType = pathToType(superCallPath);
AnonymousDescription desc = new AnonymousDescription();
desc.parameterTypes = constrType.getParameterTypes().
stream().
map(t -> varTypeName(t, false, AnonymousTypeKind.DECLARE)).
collect(List.collector());
if (node.getEnclosingExpression() != null) {
TreePath enclPath = new TreePath(tp,
node.getEnclosingExpression());
desc.enclosingInstanceType = varTypeName(pathToType(enclPath),
false,
AnonymousTypeKind.DECLARE);
}
TreePath currentPath = at.trees()
.getPath(tp.getCompilationUnit(),
node);
Type nodeType = pathToType(currentPath, node);
desc.superTypeName = varTypeName(nodeType,
false,
AnonymousTypeKind.SUPER);
desc.declareTypeName = varTypeName(nodeType,
true, AnonymousTypeKind.DECLARE);
desc.capturedVariables =
captured.stream()
.map(ve -> new VariableDesc(varTypeName((Type) ve.asType(),
false,
AnonymousTypeKind.DECLARE),
ve.getSimpleName().toString()))
.collect(List.collector());
desc.isClass = at.task.getTypes().directSupertypes(nodeType).size() == 1;
ei.anonymousClasses = ei.anonymousClasses.prepend(desc);
}
ei.anonymousClasses = ei.anonymousClasses.reverse();
}
return ei;
}
}
return null;
}
//where:
private static Set<VariableElement> capturedVariables(AnalyzeTask at,
CompilationUnitTree topLevel,
Tree tree) {
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