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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 com.google.javascript.jscomp.NodeTraversal.AbstractPostOrderCallback;
import com.google.javascript.jscomp.parsing.parser.FeatureSet;
import com.google.javascript.jscomp.parsing.parser.FeatureSet.Feature;
import com.google.javascript.rhino.IR;
import com.google.javascript.rhino.Node;
/**
* Injects JS library code that may be needed by the transpiled form of the input source code.
*
* The intention here is to add anything that could be needed and rely on `RemoveUnusedCode` to
* remove the parts that don't end up getting used. This pass should run before type checking so the
* type checking code can add type information to the injected JavaScript for checking and
* optimization purposes.
*
*
This class also reports an error if it finds getters or setters are used and the language
* output level is too low to support them. TODO(bradfordcsmith): The getter/setter check should
* probably be done separately in an earlier pass that only runs when the output language level is
* ES3 and the input language level is ES5 or greater.
*/
public final class Es6InjectRuntimeLibraries extends AbstractPostOrderCallback
implements HotSwapCompilerPass {
private final AbstractCompiler compiler;
private final boolean getterSetterSupported;
// Since there's currently no Feature for Symbol, run this pass if the code has any ES6 features.
private static final FeatureSet requiredForFeatures = FeatureSet.ES6.without(FeatureSet.ES5);
public Es6InjectRuntimeLibraries(AbstractCompiler compiler) {
this.compiler = compiler;
this.getterSetterSupported =
!FeatureSet.ES3.contains(compiler.getOptions().getOutputFeatureSet());
}
@Override
public void process(Node externs, Node root) {
FeatureSet used = FeatureSet.ES3;
for (Node script : root.children()) {
used = used.with(getScriptFeatures(script));
}
FeatureSet mustBeCompiledAway = used.without(compiler.getOptions().getOutputFeatureSet());
// TODO(johnlenz): remove this check for Symbol. Symbol should be handled like the other
// polyfills.
// Check for "Symbol" references before injecting libraries. This prevents conditional checks
// from pulling in 'Symbol'.
TranspilationPasses.processTranspile(compiler, root, requiredForFeatures, this);
// We will need these runtime methods when we transpile, but we want the runtime
// functions to be have JSType applied to it by the type inferrence.
if (mustBeCompiledAway.contains(Feature.FOR_OF)) {
Es6ToEs3Util.preloadEs6RuntimeFunction(compiler, "makeIterator");
}
if (mustBeCompiledAway.contains(Feature.ARRAY_DESTRUCTURING)) {
Es6ToEs3Util.preloadEs6RuntimeFunction(compiler, "makeIterator");
}
if (mustBeCompiledAway.contains(Feature.ARRAY_PATTERN_REST)) {
Es6ToEs3Util.preloadEs6RuntimeFunction(compiler, "arrayFromIterator");
}
if (mustBeCompiledAway.contains(Feature.SPREAD_EXPRESSIONS)) {
Es6ToEs3Util.preloadEs6RuntimeFunction(compiler, "arrayfromiterable");
}
if (mustBeCompiledAway.contains(Feature.CLASS_EXTENDS)) {
Es6ToEs3Util.preloadEs6RuntimeFunction(compiler, "inherits");
}
if (mustBeCompiledAway.contains(Feature.CLASS_GETTER_SETTER)) {
compiler.ensureLibraryInjected("util/global", /* force= */ false);
}
if (mustBeCompiledAway.contains(Feature.GENERATORS)) {
compiler.ensureLibraryInjected("es6/generator_engine", /* force= */ false);
}
if (mustBeCompiledAway.contains(Feature.ASYNC_FUNCTIONS)) {
compiler.ensureLibraryInjected("es6/execute_async_generator", /* force= */ false);
}
if (mustBeCompiledAway.contains(Feature.ASYNC_GENERATORS)) {
compiler.ensureLibraryInjected("es6/async_generator_wrapper", /* force= */ false);
}
if (mustBeCompiledAway.contains(Feature.FOR_AWAIT_OF)) {
compiler.ensureLibraryInjected("es6/util/makeasynciterator", /* force= */ false);
}
}
private static FeatureSet getScriptFeatures(Node script) {
FeatureSet features = NodeUtil.getFeatureSetOfScript(script);
return features != null ? features : FeatureSet.ES3;
}
@Override
public void hotSwapScript(Node scriptRoot, Node originalRoot) {
TranspilationPasses.hotSwapTranspile(compiler, scriptRoot, requiredForFeatures, this);
}
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
switch (n.getToken()) {
// TODO(johnlenz): remove this. Symbol should be handled like the other polyfills.
case NAME:
if (!n.isFromExterns() && isGlobalSymbol(t, n)) {
initSymbolBefore(n);
}
break;
case GETPROP:
if (!n.isFromExterns()) {
visitGetprop(t, n);
}
break;
// TODO(johnlenz): this check doesn't belong here.
case GETTER_DEF:
case SETTER_DEF:
if (!getterSetterSupported) {
Es6ToEs3Util.cannotConvert(
compiler, n, "ES5 getters/setters (consider using --language_out=ES5)");
}
break;
default:
break;
}
}
/** @return Whether {@code n} is a reference to the global "Symbol" function. */
private boolean isGlobalSymbol(NodeTraversal t, Node n) {
if (!n.matchesName("Symbol")) {
return false;
}
Var var = t.getScope().getVar("Symbol");
return var == null || var.isGlobal();
}
/** Inserts a call to $jscomp.initSymbol() before {@code n}. */
private void initSymbolBefore(Node n) {
compiler.ensureLibraryInjected("es6/symbol", false);
Node statement = NodeUtil.getEnclosingStatement(n);
Node initSymbol = IR.exprResult(IR.call(NodeUtil.newQName(compiler, "$jscomp.initSymbol")));
statement.getParent().addChildBefore(initSymbol.useSourceInfoFromForTree(statement), statement);
compiler.reportChangeToEnclosingScope(initSymbol);
}
// TODO(tbreisacher): Do this for all well-known symbols.
private void visitGetprop(NodeTraversal t, Node n) {
Node receiverNode = n.getFirstChild();
String propName = receiverNode.getNext().getString();
if (isGlobalSymbol(t, receiverNode)) {
compiler.ensureLibraryInjected("es6/symbol", false);
Node statement = NodeUtil.getEnclosingStatement(n);
switch (propName) {
case "iterator":
{
Node init =
IR.exprResult(IR.call(NodeUtil.newQName(compiler, "$jscomp.initSymbolIterator")))
.useSourceInfoFromForTree(statement);
statement.getParent().addChildBefore(init, statement);
compiler.reportChangeToEnclosingScope(init);
break;
}
case "asyncIterator":
{
Node init =
IR.exprResult(
IR.call(NodeUtil.newQName(compiler, "$jscomp.initSymbolAsyncIterator")))
.useSourceInfoFromForTree(statement);
statement.getParent().addChildBefore(init, statement);
compiler.reportChangeToEnclosingScope(init);
break;
}
default:
// TODO(bradfordcsmith): Should we warn for unrecognized symbol names?
break;
}
}
}
}