/*
* Copyright 2008 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.common.base.Preconditions;
import com.google.javascript.jscomp.GlobalNamespace.Name;
import com.google.javascript.jscomp.GlobalNamespace.Ref;
import com.google.javascript.rhino.JSDocInfo;
import com.google.javascript.rhino.Node;
import java.util.HashSet;
import java.util.Set;
/**
* Checks references to undefined properties of global variables.
*
* @author nicksantos@google.com (Nick Santos)
*/
class CheckGlobalNames implements CompilerPass {
private final AbstractCompiler compiler;
private final CodingConvention convention;
private final CheckLevel level;
private GlobalNamespace namespace = null;
private final Set<String> objectPrototypeProps = new HashSet<>();
private final Set<String> functionPrototypeProps = new HashSet<>();
// Warnings
static final DiagnosticType UNDEFINED_NAME_WARNING = DiagnosticType.warning(
"JSC_UNDEFINED_NAME",
"{0} is never defined");
static final DiagnosticType NAME_DEFINED_LATE_WARNING =
DiagnosticType.warning(
"JSC_NAME_DEFINED_LATE",
"{0} defined before its owner. {1} is defined at {2}:{3}");
static final DiagnosticType STRICT_MODULE_DEP_QNAME =
DiagnosticType.disabled(
"JSC_STRICT_MODULE_DEP_QNAME",
// The newline below causes the JS compiler not to complain when the
// referenced module's name changes because, for example, it's a
// synthetic module.
"cannot reference {2} because of a missing module dependency\n"
+ "defined in module {1}, referenced from module {0}");
/**
* Creates a pass to check global name references at the given warning level.
*/
CheckGlobalNames(AbstractCompiler compiler, CheckLevel level) {
this.compiler = compiler;
this.convention = compiler.getCodingConvention();
this.level = level;
}
/**
* Injects a pre-computed global namespace, so that the same namespace
* can be re-used for multiple check passes. Returns this for easy chaining.
*/
CheckGlobalNames injectNamespace(GlobalNamespace namespace) {
Preconditions.checkArgument(namespace.hasExternsRoot());
this.namespace = namespace;
return this;
}
@Override
public void process(Node externs, Node root) {
if (namespace == null) {
namespace = new GlobalNamespace(compiler, externs, root);
}
// Find prototype properties that will affect our analysis.
Preconditions.checkState(namespace.hasExternsRoot());
findPrototypeProps("Object", objectPrototypeProps);
findPrototypeProps("Function", functionPrototypeProps);
objectPrototypeProps.addAll(
convention.getIndirectlyDeclaredProperties());
for (Name name : namespace.getNameForest()) {
// Skip extern names. Externs are often not runnable as real code,
// and will do things like:
// var x;
// x.method;
// which this check forbids.
if (name.inExterns) {
continue;
}
checkDescendantNames(name, name.globalSets + name.localSets > 0);
}
}
private void findPrototypeProps(String type, Set<String> props) {
Name slot = namespace.getSlot(type);
if (slot != null) {
for (Ref ref : slot.getRefs()) {
if (ref.type == Ref.Type.PROTOTYPE_GET) {
Node fullName = ref.getNode().getGrandparent();
if (fullName.isGetProp()) {
props.add(fullName.getLastChild().getString());
}
}
}
}
}
/**
* Checks to make sure all the descendants of a name are defined if they
* are referenced.
*
* @param name A global name.
* @param nameIsDefined If true, {@code name} is defined. Otherwise, it's
* undefined, and any references to descendant names should emit warnings.
*/
private void checkDescendantNames(Name name, boolean nameIsDefined) {
if (name.props != null) {
for (Name prop : name.props) {
// if the ancestor of a property is not defined, then we should emit
// warnings for all references to the property.
boolean propIsDefined = false;
if (nameIsDefined) {
// if the ancestor of a property is defined, then let's check that
// the property is also explicitly defined if it needs to be.
propIsDefined = (!propertyMustBeInitializedByFullName(prop) ||
prop.globalSets + prop.localSets > 0);
}
validateName(prop, propIsDefined);
checkDescendantNames(prop, propIsDefined);
}
}
}
private void validateName(Name name, boolean isDefined) {
// If the name is not defined, emit warnings for each reference. While
// we're looking through each reference, check all the module dependencies.
Ref declaration = name.getDeclaration();
Name parent = name.parent;
JSModuleGraph moduleGraph = compiler.getModuleGraph();
for (Ref ref : name.getRefs()) {
// Don't worry about global exprs.
boolean isGlobalExpr = ref.getNode().getParent().isExprResult();
if (!isDefined && !isTypedef(ref)) {
if (!isGlobalExpr) {
reportRefToUndefinedName(name, ref);
}
} else if (declaration != null &&
ref.getModule() != declaration.getModule() &&
!moduleGraph.dependsOn(
ref.getModule(), declaration.getModule())) {
reportBadModuleReference(name, ref);
} else {
// Check for late references.
if (ref.scope.isGlobal()) {
// Prototype references are special, because in our reference graph,
// A.prototype counts as a reference to A.
boolean isPrototypeGet = (ref.type == Ref.Type.PROTOTYPE_GET);
Name owner = isPrototypeGet ? name : parent;
boolean singleGlobalParentDecl =
owner != null &&
owner.getDeclaration() != null &&
owner.localSets == 0;
if (singleGlobalParentDecl &&
owner.getDeclaration().preOrderIndex > ref.preOrderIndex) {
String refName = isPrototypeGet
? name.getFullName() + ".prototype"
: name.getFullName();
compiler.report(
JSError.make(ref.node,
NAME_DEFINED_LATE_WARNING,
refName,
owner.getFullName(),
owner.getDeclaration().getSourceFile().getName(),
String.valueOf(owner.getDeclaration().node.getLineno())));
}
}
}
}
}
private static boolean isTypedef(Ref ref) {
// If this is an annotated EXPR-GET, don't do anything.
Node parent = ref.node.getParent();
if (parent.isExprResult()) {
JSDocInfo info = ref.node.getJSDocInfo();
if (info != null && info.hasTypedefType()) {
return true;
}
}
return false;
}
private void reportBadModuleReference(Name name, Ref ref) {
compiler.report(
JSError.make(ref.node, STRICT_MODULE_DEP_QNAME,
ref.getModule().getName(),
name.getDeclaration().getModule().getName(),
name.getFullName()));
}
private void reportRefToUndefinedName(Name name, Ref ref) {
// grab the highest undefined ancestor to output in the warning message.
while (name.parent != null &&
name.parent.globalSets + name.parent.localSets == 0) {
name = name.parent;
}
compiler.report(
JSError.make(ref.node, level,
UNDEFINED_NAME_WARNING, name.getFullName()));
}
/**
* The input name is a property. Check whether this property
* must be initialized with its full qualified name.
*/
private boolean propertyMustBeInitializedByFullName(Name name) {
// If an object or function literal in the global namespace is never
// aliased, then its properties can only come from one of 2 places:
// 1) From its prototype chain, or
// 2) From an assignment to its fully qualified name.
// If we assume #1 is not the case, then #2 implies that its
// properties must all be modeled in the GlobalNamespace as well.
//
// We assume that for global object literals and types (constructors and
// interfaces), we can find all the properties inherited from the prototype
// chain of functions and objects.
if (name.parent == null) {
return false;
}
boolean parentIsAliased = false;
if (name.parent.aliasingGets > 0) {
for (Ref ref : name.parent.getRefs()) {
if (ref.type == Ref.Type.ALIASING_GET) {
Node aliaser = ref.getNode().getParent();
// We don't need to worry about known aliased, because
// they're already covered by the getIndirectlyDeclaredProperties
// call at the top.
boolean isKnownAlias =
aliaser.isCall() &&
(convention.getClassesDefinedByCall(aliaser) != null ||
convention.getSingletonGetterClassName(aliaser) != null);
if (!isKnownAlias) {
parentIsAliased = true;
}
}
}
}
if (parentIsAliased) {
return false;
}
if (objectPrototypeProps.contains(name.getBaseName())) {
return false;
}
if (name.parent.type == Name.Type.OBJECTLIT
|| name.parent.type == Name.Type.CLASS) {
return true;
}
return name.parent.type == Name.Type.FUNCTION && name.parent.isDeclaredType()
&& !functionPrototypeProps.contains(name.getBaseName());
}
}