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Liferay Frontend JS Minifier
/*
* 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.refactoring;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import com.google.common.collect.ImmutableList;
import com.google.javascript.jscomp.AbstractCompiler;
import com.google.javascript.jscomp.JSError;
import com.google.javascript.jscomp.NodeTraversal;
import com.google.javascript.jscomp.NodeUtil;
import com.google.javascript.jscomp.lint.CheckProvidesSorted;
import com.google.javascript.jscomp.lint.CheckRequiresSorted;
import com.google.javascript.refactoring.SuggestedFix.ImportType;
import com.google.javascript.rhino.IR;
import com.google.javascript.rhino.JSDocInfo;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.Token;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Maps a {@code JSError} to a list of {@code SuggestedFix}es, if possible.
* TODO(tbreisacher): Move this into the compiler itself (i.e. into the jscomp package). This will
* make it easier for people adding new warnings to also add fixes for them.
*/
public final class ErrorToFixMapper {
private static final Pattern DID_YOU_MEAN = Pattern.compile(".*Did you mean (.*)\\?");
private static final Pattern EARLY_REF =
Pattern.compile("Variable referenced before declaration: (.*)");
private static final Pattern MISSING_REQUIRE =
Pattern.compile("'([^']+)' references a .*", Pattern.DOTALL);
private static final Pattern FULLY_QUALIFIED_NAME =
Pattern.compile("Reference to fully qualified import name '([^']+)'.*");
private static final Pattern USE_SHORT_NAME =
Pattern.compile(".*Please use the short name '(.*)' instead.");
private final AbstractCompiler compiler;
private final LinkedHashMap metadataForEachScript = new LinkedHashMap<>();
public ErrorToFixMapper(AbstractCompiler compiler) {
this.compiler = compiler;
}
public ImmutableList getFixesForJsError(JSError error) {
SuggestedFix fix = getFixForJsError(error);
if (fix != null) {
return ImmutableList.of(fix);
}
switch (error.getType().key) {
case "JSC_IMPLICITLY_NONNULL_JSDOC":
case "JSC_IMPLICITLY_NULLABLE_JSDOC":
case "JSC_MISSING_NULLABILITY_MODIFIER_JSDOC":
case "JSC_NULL_MISSING_NULLABILITY_MODIFIER_JSDOC":
return getFixesForImplicitNullabilityErrors(error);
default:
return ImmutableList.of();
}
}
/**
* Creates a SuggestedFix for the given error. Note that some errors have multiple fixes so
* getFixesForJsError should often be used instead of this.
*/
public SuggestedFix getFixForJsError(JSError error) {
switch (error.getType().key) {
case "JSC_REDECLARED_VARIABLE":
return getFixForRedeclaration(error);
case "JSC_REFERENCE_BEFORE_DECLARE":
return getFixForEarlyReference(error);
case "JSC_MISSING_SEMICOLON":
return getFixForMissingSemicolon(error);
case "JSC_REQUIRES_NOT_SORTED":
return getFixForUnsortedRequires(error);
case "JSC_PROVIDES_NOT_SORTED":
return getFixForUnsortedProvides(error);
case "JSC_DEBUGGER_STATEMENT_PRESENT":
return new SuggestedFix.Builder()
.attachMatchedNodeInfo(error.getNode(), compiler)
.setDescription("Remove debugger statement")
.delete(error.getNode())
.build();
case "JSC_USELESS_EMPTY_STATEMENT":
return removeEmptyStatement(error);
case "JSC_INEXISTENT_PROPERTY_WITH_SUGGESTION":
case "JSC_STRICT_INEXISTENT_PROPERTY_WITH_SUGGESTION":
return getFixForInexistentProperty(error);
case "JSC_MISSING_CALL_TO_SUPER":
return getFixForMissingSuper(error);
case "JSC_INVALID_SUPER_CALL_WITH_SUGGESTION":
return getFixForInvalidSuper(error);
case "JSC_MISSING_REQUIRE":
case "JSC_MISSING_REQUIRE_IN_PROVIDES_FILE":
return getFixForMissingRequire(error, ImportType.REQUIRE);
case "JSC_MISSING_REQUIRE_TYPE":
case "JSC_MISSING_REQUIRE_TYPE_IN_PROVIDES_FILE":
return getFixForMissingRequire(error, ImportType.REQUIRE_TYPE);
case "JSC_EXTRA_REQUIRE_WARNING":
return getFixForExtraRequire(error);
case "JSC_REFERENCE_TO_SHORT_IMPORT_BY_LONG_NAME_INCLUDING_SHORT_NAME":
case "JSC_REFERENCE_TO_FULLY_QUALIFIED_IMPORT_NAME":
return getFixForReferenceToShortImportByLongName(error);
case "JSC_REDUNDANT_NULLABILITY_MODIFIER_JSDOC":
return getFixForRedundantNullabilityModifierJsDoc(error);
case "JSC_MISSING_CONST_ON_CONSTANT_CASE":
return getFixForConstantCaseErrors(error);
default:
return null;
}
}
private SuggestedFix getFixForRedeclaration(JSError error) {
Node name = error.getNode();
checkState(name.isName(), name);
Node parent = name.getParent();
if (!NodeUtil.isNameDeclaration(parent)) {
return null;
}
SuggestedFix.Builder fix = new SuggestedFix.Builder().attachMatchedNodeInfo(name, compiler);
if (!name.hasChildren()) {
Node nodeToDelete = parent.hasOneChild() ? parent : error.getNode();
return fix.setDescription("Remove redundant declaration").delete(nodeToDelete).build();
}
fix.setDescription("Convert redundant declaration to assignment");
Node assign = IR.exprResult(
IR.assign(name.cloneNode(), name.getFirstChild().cloneTree()));
if (parent.hasOneChild()) {
return fix.replace(parent, assign, compiler).build();
}
// Split the var statement into an assignment and up to two var statements.
// var a = 0,
// b = 1, // This is the one we're removing.
// c = 2;
//
// becomes
//
// var a = 0; // This is the "added" var statement.
// b = 1;
// var c = 2; // This is the original var statement.
List childrenOfAddedVarStatement = new ArrayList<>();
for (Node n = parent.getFirstChild(); n != null; n = n.getNext()) {
if (n == name) {
break;
}
childrenOfAddedVarStatement.add(n);
}
if (!childrenOfAddedVarStatement.isEmpty()) {
Node var = new Node(parent.getToken());
for (Node n : childrenOfAddedVarStatement) {
var.addChildToBack(n.cloneTree());
}
// Use a sortKey of "1" to make sure this is applied before the statement below.
fix.insertBefore(parent, var, compiler, "1");
}
if (name.getNext() != null) {
// Keep the original var statement, just remove the names that will be put in the added one.
for (Node n : childrenOfAddedVarStatement) {
fix.delete(n);
}
fix.delete(name);
// Use a sortKey of "2" to make sure this is applied after the statement above.
fix.insertBefore(parent, assign, compiler, "2");
} else {
// Remove the original var statement.
fix.replace(parent, assign, compiler);
}
return fix.build();
}
/**
* This fix is not ideal. It trades one warning (JSC_REFERENCE_BEFORE_DECLARE) for another
* (JSC_REDECLARED_VARIABLE). But after running the fixer once, you can then run it again and
* #getFixForRedeclaration will take care of the JSC_REDECLARED_VARIABLE warning.
*/
private SuggestedFix getFixForEarlyReference(JSError error) {
Matcher m = EARLY_REF.matcher(error.getDescription());
if (m.matches()) {
String name = m.group(1);
Node stmt = NodeUtil.getEnclosingStatement(error.getNode());
return new SuggestedFix.Builder()
.attachMatchedNodeInfo(error.getNode(), compiler)
.setDescription("Insert var declaration statement")
.insertBefore(stmt, "var " + name + ";\n")
.build();
}
return null;
}
private SuggestedFix getFixForReferenceToShortImportByLongName(JSError error) {
SuggestedFix.Builder fix =
new SuggestedFix.Builder().attachMatchedNodeInfo(error.getNode(), compiler);
NodeMetadata metadata = new NodeMetadata(compiler);
Match match = new Match(error.getNode(), metadata);
Node script = compiler.getScriptNode(error.getSourceName());
ScriptMetadata scriptMetadata = this.getMetadataForScript(script);
Matcher fullNameMatcher = FULLY_QUALIFIED_NAME.matcher(error.getDescription());
checkState(fullNameMatcher.matches(), error.getDescription());
String fullName = fullNameMatcher.group(1);
Matcher shortNameMatcher = USE_SHORT_NAME.matcher(error.getDescription());
String shortName;
if (shortNameMatcher.matches()) {
shortName = shortNameMatcher.group(1);
} else {
fix.addGoogRequire(match, fullName, scriptMetadata);
shortName = scriptMetadata.getAlias(fullName);
}
String oldName =
error.getNode().isQualifiedName()
? error.getNode().getQualifiedName()
: error.getNode().getString();
return fix.replace(
error.getNode(),
NodeUtil.newQName(compiler, oldName.replace(fullName, shortName)),
compiler)
.build();
}
private ImmutableList getFixesForImplicitNullabilityErrors(JSError error) {
if (error.getNode().getSourceFileName() == null) {
// If we don't have a source location we can't generate a valid fix.
return ImmutableList.of();
}
SuggestedFix qmark =
new SuggestedFix.Builder()
.attachMatchedNodeInfo(error.getNode(), compiler)
.insertBefore(error.getNode(), "?")
.setDescription("Make nullability explicit")
.build();
SuggestedFix bang =
new SuggestedFix.Builder()
.attachMatchedNodeInfo(error.getNode(), compiler)
.insertBefore(error.getNode(), "!")
.setDescription("Make type non-nullable")
.build();
switch (error.getType().key) {
case "JSC_NULL_MISSING_NULLABILITY_MODIFIER_JSDOC":
// When initializer was null, we can be confident about nullability
return ImmutableList.of(qmark);
case "JSC_MISSING_NULLABILITY_MODIFIER_JSDOC":
// Otherwise, the linter should assume ! is preferred over ?.
return ImmutableList.of(bang, qmark);
case "JSC_IMPLICITLY_NULLABLE_JSDOC":
// The type-based check prefers ? over ! since it only warns for names that are nullable.
return ImmutableList.of(qmark, bang);
case "JSC_IMPLICITLY_NONNULL_JSDOC":
// Using type-information, we can also be confident about ! for enums and typedefs.
return ImmutableList.of(bang);
default:
throw new IllegalArgumentException("Unexpected JSError Type: " + error.getType().key);
}
}
private SuggestedFix removeEmptyStatement(JSError error) {
return new SuggestedFix.Builder()
.attachMatchedNodeInfo(error.getNode(), compiler)
.setDescription("Remove empty statement")
.deleteWithoutRemovingWhitespace(error.getNode())
.build();
}
private SuggestedFix getFixForMissingSemicolon(JSError error) {
return new SuggestedFix.Builder()
.attachMatchedNodeInfo(error.getNode(), compiler)
.insertAfter(error.getNode(), ";")
.build();
}
private SuggestedFix getFixForMissingSuper(JSError error) {
Node constructorFunction = error.getNode().getFirstChild();
Node body = NodeUtil.getFunctionBody(constructorFunction);
return new SuggestedFix.Builder()
.attachMatchedNodeInfo(error.getNode(), compiler)
.addChildToFront(body, "super();")
.build();
}
private SuggestedFix getFixForInvalidSuper(JSError error) {
Matcher m = DID_YOU_MEAN.matcher(error.getDescription());
if (m.matches()) {
String superDotSuggestion = checkNotNull(m.group(1));
return new SuggestedFix.Builder()
.attachMatchedNodeInfo(error.getNode(), compiler)
.setDescription("Call '" + superDotSuggestion + "' instead")
.replace(error.getNode(), NodeUtil.newQName(compiler, superDotSuggestion), compiler)
.build();
}
return null;
}
private SuggestedFix getFixForInexistentProperty(JSError error) {
Matcher m = DID_YOU_MEAN.matcher(error.getDescription());
if (m.matches()) {
String suggestedPropName = m.group(1);
return new SuggestedFix.Builder()
.attachMatchedNodeInfo(error.getNode(), compiler)
.setDescription("Change property name to '" + suggestedPropName + "'")
.rename(error.getNode(), suggestedPropName)
.build();
}
return null;
}
private SuggestedFix getFixForMissingRequire(JSError error, ImportType importType) {
Matcher regexMatcher = MISSING_REQUIRE.matcher(error.getDescription());
checkState(regexMatcher.matches(), "Unexpected error description: %s", error.getDescription());
String namespaceToRequire = regexMatcher.group(1);
String qName =
error.getNode().isQualifiedName()
? error.getNode().getQualifiedName()
: error.getNode().getString();
checkState(
qName.startsWith(namespaceToRequire),
"Expected error location %s to start with namespace <%s>",
error.getNode(),
namespaceToRequire);
Node script = compiler.getScriptNode(error.getSourceName());
ScriptMetadata scriptMetadata = this.getMetadataForScript(script);
NodeMetadata metadata = new NodeMetadata(compiler);
Match match = new Match(error.getNode(), metadata);
SuggestedFix.Builder fix =
new SuggestedFix.Builder()
.attachMatchedNodeInfo(error.getNode(), compiler)
.addImport(match, namespaceToRequire, importType, scriptMetadata);
String alias = scriptMetadata.getAlias(namespaceToRequire);
if (alias != null) {
fix.replace(
error.getNode(),
NodeUtil.newQName(compiler, qName.replace(namespaceToRequire, alias)),
compiler);
}
return fix.build();
}
private SuggestedFix getFixForExtraRequire(JSError error) {
Node node = error.getNode();
SuggestedFix.Builder fix = new SuggestedFix.Builder().attachMatchedNodeInfo(node, compiler);
boolean destructuring = NodeUtil.getEnclosingType(node, Token.OBJECT_PATTERN) != null;
if (destructuring) {
fix.setDescription("Delete unused symbol");
if (node.isStringKey()) {
fix.delete(node);
} else {
checkState(node.getParent().isStringKey(), node.getParent());
fix.delete(node.getParent());
}
} else {
fix.setDescription("Delete extra require");
fix.deleteWithoutRemovingWhitespaceBefore(NodeUtil.getEnclosingStatement(node));
}
return fix.build();
}
private SuggestedFix getFixForUnsortedRequires(JSError error) {
// TODO(tjgq): Encode enough information in the error to avoid the need to run a traversal in
// order to produce the fix.
Node script = NodeUtil.getEnclosingScript(error.getNode());
CheckRequiresSorted callback = new CheckRequiresSorted(CheckRequiresSorted.Mode.COLLECT_ONLY);
NodeTraversal.traverse(compiler, script, callback);
if (!callback.needsFix()) {
return null;
}
return new SuggestedFix.Builder()
.attachMatchedNodeInfo(callback.getFirstNode(), compiler)
.replaceRange(callback.getFirstNode(), callback.getLastNode(), callback.getReplacement())
.build();
}
private SuggestedFix getFixForUnsortedProvides(JSError error) {
// TODO(tjgq): Encode enough information in the error to avoid the need to run a traversal in
// order to produce the fix.
Node script = NodeUtil.getEnclosingScript(error.getNode());
CheckProvidesSorted callback = new CheckProvidesSorted(CheckProvidesSorted.Mode.COLLECT_ONLY);
NodeTraversal.traverse(compiler, script, callback);
if (!callback.needsFix()) {
return null;
}
return new SuggestedFix.Builder()
.attachMatchedNodeInfo(callback.getFirstNode(), compiler)
.replaceRange(callback.getFirstNode(), callback.getLastNode(), callback.getReplacement())
.build();
}
private SuggestedFix getFixForRedundantNullabilityModifierJsDoc(JSError error) {
return new SuggestedFix.Builder()
.attachMatchedNodeInfo(error.getNode(), compiler)
.replaceText(error.getNode(), 1, "")
.build();
}
/**
* Suggests a fix for a constant case error.
*
* If the variable is in a let clause, suggest adding a const. If the variable is not, suggest
* adding a @const annotation. Don't try to adjust the JSDoc, because that can produce invalid
* output.
*/
private SuggestedFix getFixForConstantCaseErrors(JSError error) {
Node n = error.getNode();
Node parent = n.getParent();
if (!n.isName() || !NodeUtil.isNameDeclaration(parent)) {
return null;
}
if (parent.isLet()) {
// Convert to a `const` declaration
return new SuggestedFix.Builder()
.setDescription("Make explicitly constant")
.attachMatchedNodeInfo(parent, compiler)
.replaceText(parent, 3, "const")
.build();
}
// Don't convert a `var` to a `const` to avoid breaking variable scoping.
checkState(parent.isVar(), parent);
JSDocInfo info = parent.getJSDocInfo();
if (info == null) {
return new SuggestedFix.Builder()
.setDescription("Make explicitly constant")
.attachMatchedNodeInfo(parent, compiler)
.addOrReplaceJsDoc(parent, "/** @const */\n")
.build();
}
return null;
}
private ScriptMetadata getMetadataForScript(Node script) {
checkArgument(script.isScript());
return this.metadataForEachScript.computeIfAbsent(
script, (s) -> ScriptMetadata.create(s, this.compiler));
}
}