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/*
* Copyright 2014 The Closure Compiler Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.javascript.jscomp;
import static com.google.common.base.Preconditions.checkState;
import static com.google.javascript.jscomp.AstFactory.type;
import static com.google.javascript.jscomp.TranspilationUtil.CANNOT_CONVERT_YET;
import com.google.javascript.jscomp.parsing.parser.FeatureSet;
import com.google.javascript.jscomp.parsing.parser.FeatureSet.Feature;
import com.google.javascript.rhino.JSDocInfo;
import com.google.javascript.rhino.Node;
/**
* Converts {@code super.method()} calls and adds constructors to any classes that lack them.
*
* This has to run before the main {@link Es6RewriteClass} pass. The super() constructor calls
* are not converted here, but rather in {@link Es6ConvertSuperConstructorCalls}, which runs later.
*/
public final class Es6ConvertSuper extends NodeTraversal.AbstractPostOrderCallback
implements CompilerPass {
private final AbstractCompiler compiler;
private final AstFactory astFactory;
private final SynthesizeExplicitConstructors constructorSynthesizer;
private static final FeatureSet transpiledFeatures = FeatureSet.BARE_MINIMUM.with(Feature.SUPER);
public Es6ConvertSuper(AbstractCompiler compiler) {
this.compiler = compiler;
this.astFactory = compiler.createAstFactory();
this.constructorSynthesizer = new SynthesizeExplicitConstructors(compiler);
}
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
if (n.isClass()) {
constructorSynthesizer.synthesizeClassConstructorIfMissing(t, n);
} else if (n.isSuper()) {
visitSuper(n, parent);
}
}
private boolean isInterface(Node classNode) {
JSDocInfo classJsDocInfo = NodeUtil.getBestJSDocInfo(classNode);
return classJsDocInfo != null && classJsDocInfo.isInterface();
}
private void visitSuper(Node node, Node parent) {
checkState(node.isSuper());
Node exprRoot = node;
if (exprRoot.getParent().isGetElem() || exprRoot.getParent().isGetProp()) {
exprRoot = exprRoot.getParent();
}
Node enclosingMemberDef =
NodeUtil.getEnclosingNode(
exprRoot,
(Node n) -> {
switch (n.getToken()) {
case MEMBER_FUNCTION_DEF:
case GETTER_DEF:
case SETTER_DEF:
case COMPUTED_PROP:
return true;
default:
return false;
}
});
if (parent.isCall()) {
// super(...)
visitSuperCall(node, parent, enclosingMemberDef);
} else if (parent.isGetProp() || parent.isGetElem()) {
if (parent.getFirstChild() == node) {
if (parent.getParent().isCall() && NodeUtil.isInvocationTarget(parent)) {
// super.something(...) or super['something'](..)
visitSuperPropertyCall(node, parent, enclosingMemberDef);
} else {
// super.something or super['something']
visitSuperPropertyAccess(node, parent, enclosingMemberDef);
}
} else {
// super.something used in some other way
compiler.report(
JSError.make(
node,
CANNOT_CONVERT_YET,
"Only calls to super or to a method of super are supported."));
}
} else if (parent.isNew()) {
throw new IllegalStateException("This should never happen. Did Es6SuperCheck fail to run?");
} else {
// some other use of super we don't support yet
compiler.report(
JSError.make(
node,
CANNOT_CONVERT_YET,
"Only calls to super or to a method of super are supported."));
}
}
private void visitSuperCall(Node node, Node parent, Node enclosingMemberDef) {
checkState(parent.isCall(), parent);
checkState(node.isSuper(), node);
Node clazz = NodeUtil.getEnclosingClass(node);
Node superName = clazz.getSecondChild();
if (!superName.isQualifiedName()) {
// This will be reported as an error in Es6ToEs3Converter.
return;
}
if (NodeUtil.isEs6ConstructorMemberFunctionDef(enclosingMemberDef)) {
// Calls to super() constructors will be transpiled by Es6ConvertSuperConstructorCalls later.
if (node.isFromExterns() || isInterface(clazz)) {
// If a class is defined in an externs file or as an interface, it's only a stub, not an
// implementation that should be instantiated.
// A call to super() shouldn't actually exist for these cases and is problematic to
// transpile, so just drop it.
Node enclosingStatement = NodeUtil.getEnclosingStatement(node);
Node enclosingStatementParent = enclosingStatement.getParent();
enclosingStatement.detach();
compiler.reportChangeToEnclosingScope(enclosingStatementParent);
}
// Calls to super() constructors will be transpiled by Es6ConvertSuperConstructorCalls
// later.
return;
} else {
// super can only be directly called in a constructor
throw new IllegalStateException("This should never happen. Did Es6SuperCheck fail to run?");
}
}
private void visitSuperPropertyCall(Node node, Node parent, Node enclosingMemberDef) {
checkState(parent.isGetProp() || parent.isGetElem(), parent);
checkState(node.isSuper(), node);
Node grandparent = parent.getParent();
checkState(grandparent.isCall());
Node clazz = NodeUtil.getEnclosingClass(node);
Node superName = clazz.getSecondChild();
if (!superName.isQualifiedName()) {
// This will be reported as an error in Es6ToEs3Converter.
return;
}
Node callTarget = parent;
if (enclosingMemberDef.isStaticMember()) {
Node expandedSuper = superName.cloneTree().srcrefTree(node);
expandedSuper.setOriginalName("super");
node.replaceWith(expandedSuper);
callTarget = astFactory.createGetPropWithUnknownType(callTarget.detach(), "call");
grandparent.addChildToFront(callTarget);
Node thisNode = astFactory.createThis(type(clazz));
thisNode.makeNonIndexable(); // no direct correlation with original source
thisNode.insertAfter(callTarget);
grandparent.srcrefTreeIfMissing(parent);
} else {
// Replace super node to give
// super.method(...) -> SuperClass.prototype.method(...)
Node expandedSuper = astFactory.createPrototypeAccess(superName.cloneTree()).srcrefTree(node);
expandedSuper.setOriginalName("super");
node.replaceWith(expandedSuper);
// Set the 'this' object correctly for the call
// SuperClass.prototype.method(...) -> SuperClass.prototype.method.call(this, ...)
callTarget = astFactory.createGetPropWithUnknownType(callTarget.detach(), "call");
grandparent.addChildToFront(callTarget);
Node thisNode = astFactory.createThisForEs6Class(clazz);
thisNode.makeNonIndexable(); // no direct correlation with original source
thisNode.insertAfter(callTarget);
grandparent.putBooleanProp(Node.FREE_CALL, false);
grandparent.srcrefTreeIfMissing(parent);
}
compiler.reportChangeToEnclosingScope(grandparent);
}
private void visitSuperPropertyAccess(Node node, Node parent, Node enclosingMemberDef) {
checkState(parent.isGetProp() || parent.isGetElem(), parent);
checkState(node.isSuper(), node);
Node grandparent = parent.getParent();
if (NodeUtil.isLValue(parent)) {
// We don't support assigning to a super property
compiler.report(JSError.make(parent, CANNOT_CONVERT_YET, "assigning to a super property"));
return;
}
Node clazz = NodeUtil.getEnclosingClass(node);
Node superName = clazz.getSecondChild();
if (!superName.isQualifiedName()) {
// This will be reported as an error in Es6ToEs3Converter.
return;
}
if (enclosingMemberDef.isStaticMember()) {
// super.prop -> SuperClass.prop
Node expandedSuper = superName.cloneTree().srcrefTree(node);
expandedSuper.setOriginalName("super");
node.replaceWith(expandedSuper);
} else {
// super.prop -> SuperClass.prototype.prop
Node newprop = astFactory.createPrototypeAccess(superName.cloneTree()).srcrefTree(node);
newprop.setOriginalName("super");
node.replaceWith(newprop);
}
compiler.reportChangeToEnclosingScope(grandparent);
}
@Override
public void process(Node externs, Node root) {
// Might need to synthesize constructors for ambient classes in .d.ts externs
TranspilationPasses.processTranspile(compiler, externs, transpiledFeatures, this);
TranspilationPasses.processTranspile(compiler, root, transpiledFeatures, this);
}
}