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Liferay Frontend JS Minifier
/*
* Copyright 2009 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.rhino.JSDocInfo;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.jstype.JSType;
import java.util.HashSet;
/**
* Checks that the code obeys the static restrictions of strict mode:
*
* - No use of "with".
*
- No deleting variables, functions, or arguments.
*
- No re-declarations or assignments of "eval" or arguments.
*
- No use of arguments.callee
*
- No use of arguments.caller
*
- Class: Always under strict mode
*
- In addition, no duplicate class method names
*
*/
class StrictModeCheck extends AbstractPostOrderCallback
implements CompilerPass {
static final DiagnosticType USE_OF_WITH =
DiagnosticType.error(
"JSC_USE_OF_WITH", "The 'with' statement cannot be used in strict mode.");
static final DiagnosticType EVAL_DECLARATION =
DiagnosticType.error("JSC_EVAL_DECLARATION", "\"eval\" cannot be redeclared in strict mode");
static final DiagnosticType EVAL_ASSIGNMENT =
DiagnosticType.error(
"JSC_EVAL_ASSIGNMENT", "the \"eval\" object cannot be reassigned in strict mode");
static final DiagnosticType ARGUMENTS_DECLARATION =
DiagnosticType.error(
"JSC_ARGUMENTS_DECLARATION", "\"arguments\" cannot be redeclared in strict mode");
static final DiagnosticType ARGUMENTS_ASSIGNMENT =
DiagnosticType.error(
"JSC_ARGUMENTS_ASSIGNMENT",
"the \"arguments\" object cannot be reassigned in strict mode");
static final DiagnosticType ARGUMENTS_CALLEE_FORBIDDEN =
DiagnosticType.error(
"JSC_ARGUMENTS_CALLEE_FORBIDDEN", "\"arguments.callee\" cannot be used in strict mode");
static final DiagnosticType ARGUMENTS_CALLER_FORBIDDEN =
DiagnosticType.error(
"JSC_ARGUMENTS_CALLER_FORBIDDEN", "\"arguments.caller\" cannot be used in strict mode");
static final DiagnosticType FUNCTION_CALLER_FORBIDDEN =
DiagnosticType.error(
"JSC_FUNCTION_CALLER_FORBIDDEN",
"A function''s \"caller\" property cannot be used in strict mode");
static final DiagnosticType FUNCTION_ARGUMENTS_PROP_FORBIDDEN =
DiagnosticType.error(
"JSC_FUNCTION_ARGUMENTS_PROP_FORBIDDEN",
"A function''s \"arguments\" property cannot be used in strict mode");
static final DiagnosticType DELETE_VARIABLE =
DiagnosticType.error(
"JSC_DELETE_VARIABLE",
"variables, functions, and arguments cannot be deleted in strict mode");
static final DiagnosticType DUPLICATE_MEMBER =
DiagnosticType.warning(
"JSC_DUPLICATE_MEMBER",
"Class or object literal contains duplicate member \"{0}\". In non-strict code, the last"
+ " duplicate will overwrite the others.");
private final AbstractCompiler compiler;
private final CheckLevel defaultLevel;
StrictModeCheck(AbstractCompiler compiler, CheckLevel defaultLevel) {
this.compiler = compiler;
this.defaultLevel = defaultLevel;
}
@Override
public void process(Node externs, Node root) {
NodeTraversal.traverseRoots(compiler, this, externs, root);
NodeTraversal.traverse(compiler, root, new NonExternChecks());
}
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
if (n.isAssign()) {
checkAssignment(n);
} else if (n.isDelProp()) {
checkDelete(t, n);
} else if (n.isObjectLit()) {
checkObjectLiteralOrClass(n);
} else if (n.isClass()) {
checkObjectLiteralOrClass(n.getLastChild());
} else if (n.isWith()) {
checkWith(n);
}
}
/** Reports a warning for with statements. */
private void checkWith(Node n) {
JSDocInfo info = n.getJSDocInfo();
boolean allowWith = info != null && info.getSuppressions().contains("with");
if (!allowWith) {
this.report(n, USE_OF_WITH);
}
}
/**
* Determines if the given name is a declaration, which can be a declaration
* of a variable, function, or argument.
*/
private static boolean isDeclaration(Node n) {
switch (n.getParent().getToken()) {
case LET:
case CONST:
case VAR:
case CATCH:
return true;
case FUNCTION:
return n == n.getParent().getFirstChild();
case PARAM_LIST:
return n.getGrandparent().isFunction();
default:
return false;
}
}
/** Checks that an assignment is not to the "arguments" object. */
private void checkAssignment(Node n) {
if (n.getFirstChild().isName()) {
if ("arguments".equals(n.getFirstChild().getString())) {
this.report(n, ARGUMENTS_ASSIGNMENT);
} else if ("eval".equals(n.getFirstChild().getString())) {
// Note that assignment to eval is already illegal because any use of
// that name is illegal.
this.report(n, EVAL_ASSIGNMENT);
}
}
}
/** Checks that variables, functions, and arguments are not deleted. */
private void checkDelete(NodeTraversal t, Node n) {
if (n.getFirstChild().isName()) {
Var v = t.getScope().getVar(n.getFirstChild().getString());
if (v != null) {
this.report(n, DELETE_VARIABLE);
}
}
}
/** Checks that object literal keys or class method names are valid. */
private void checkObjectLiteralOrClass(Node n) {
HashSet getters = new HashSet<>();
HashSet setters = new HashSet<>();
HashSet staticGetters = new HashSet<>();
HashSet staticSetters = new HashSet<>();
/**
* Iterate backwards because the last duplicate is the one that will be used in sloppy or ES6
* code. The earlier duplicates are the ones that should be removed.
*/
for (Node key = n.getLastChild(); key != null; key = key.getPrevious()) {
if (key.isEmpty() || key.isComputedProp() || key.isSpread() || key.isComputedFieldDef()) {
continue;
}
String keyName = key.getString();
if (!key.isSetterDef()) {
// normal property and getter cases
HashSet set = key.isStaticMember() ? staticGetters : getters;
if (!set.add(keyName)) {
this.report(key, DUPLICATE_MEMBER, keyName);
}
}
if (!key.isGetterDef()) {
// normal property and setter cases
HashSet set = key.isStaticMember() ? staticSetters : setters;
if (!set.add(keyName)) {
this.report(key, DUPLICATE_MEMBER, keyName);
}
}
}
}
/** Checks that are performed on non-extern code only. */
private class NonExternChecks extends AbstractPostOrderCallback {
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
if (n.isName() && isDeclaration(n)) {
checkDeclaration(n);
} else if (n.isGetProp()) {
checkGetProp(n);
}
}
/** Checks for illegal declarations. */
private void checkDeclaration(Node n) {
if ("eval".equals(n.getString())) {
report(n, EVAL_DECLARATION);
} else if ("arguments".equals(n.getString())) {
report(n, ARGUMENTS_DECLARATION);
}
}
/** Checks that the arguments.callee is not used. */
private void checkGetProp(Node n) {
Node target = n.getFirstChild();
String name = n.getString();
if (name.equals("callee")) {
if (target.isName() && target.getString().equals("arguments")) {
report(n, ARGUMENTS_CALLEE_FORBIDDEN);
}
} else if (name.equals("caller")) {
if (target.isName() && target.getString().equals("arguments")) {
report(n, ARGUMENTS_CALLER_FORBIDDEN);
} else if (isFunctionType(target)) {
report(n, FUNCTION_CALLER_FORBIDDEN);
}
} else if (name.equals("arguments") && isFunctionType(target)) {
report(n, FUNCTION_ARGUMENTS_PROP_FORBIDDEN);
}
}
}
private static boolean isFunctionType(Node n) {
JSType type = n.getJSType();
return (type != null && type.isFunctionType());
}
private void report(Node n, DiagnosticType diagnostic, String... args) {
this.compiler.report(JSError.make(n, this.defaultLevel, diagnostic, args));
}
}