/**
* Flattens all references to a collapsible property of a global name except its initial
* definition.
*
* @param n A global property name (e.g. "a.b" or "a.b.c.d")
* @param alias The flattened name (e.g. "a$b" or "a$b$c$d")
*/
private void flattenReferencesTo(Name n, String alias) {
String originalName = n.getFullName();
for (Ref r : n.getRefs()) {
if (r == n.getDeclaration()) {
// Declarations are handled separately.
continue;
}
Node rParent = r.node.getParent();
// There are two cases when we shouldn't flatten a reference:
// 1) Object literal keys, because duplicate keys show up as refs.
// 2) References inside a complex assign. (a = x.y = 0). These are
// called TWIN references, because they show up twice in the
// reference list. Only collapse the set, not the alias.
if (!NodeUtil.isObjectLitKey(r.node) && (r.getTwin() == null || r.isSet())) {
flattenNameRef(alias, r.node, rParent, originalName);
}
}
// Flatten all occurrences of a name as a prefix of its subnames. For
// example, if {@code n} corresponds to the name "a.b", then "a.b" will be
// replaced with "a$b" in all occurrences of "a.b.c", "a.b.c.d", etc.
if (n.props != null) {
for (Name p : n.props) {
flattenPrefixes(alias, p, 1);
}
}
}
/**
* Flattens all occurrences of a name as a prefix of subnames beginning with a particular subname.
*
* @param n A global property name (e.g. "a.b.c.d")
* @param alias A flattened prefix name (e.g. "a$b")
* @param depth The difference in depth between the property name and the prefix name (e.g. 2)
*/
private void flattenPrefixes(String alias, Name n, int depth) {
// Only flatten the prefix of a name declaration if the name being
// initialized is fully qualified (i.e. not an object literal key).
String originalName = n.getFullName();
Ref decl = n.getDeclaration();
if (decl != null && decl.node != null && decl.node.isGetProp()) {
flattenNameRefAtDepth(alias, decl.node, depth, originalName);
}
for (Ref r : n.getRefs()) {
if (r == decl) {
// Declarations are handled separately.
continue;
}
// References inside a complex assign (a = x.y = 0)
// have twins. We should only flatten one of the twins.
if (r.getTwin() == null || r.isSet()) {
flattenNameRefAtDepth(alias, r.node, depth, originalName);
}
}
if (n.props != null) {
for (Name p : n.props) {
flattenPrefixes(alias, p, depth + 1);
}
}
}
/**
* Runs through all namespaces (prefixes of classes and enums), and checks if any of them have
* been used in an unsafe way.
*/
private void checkNamespaces() {
for (Name name : nameMap.values()) {
if (name.isNamespaceObjectLit()
&& (name.aliasingGets > 0
|| name.localSets + name.globalSets > 1
|| name.deleteProps > 0)) {
boolean initialized = name.getDeclaration() != null;
for (Ref ref : name.getRefs()) {
if (ref == name.getDeclaration()) {
continue;
}
if (ref.type == Ref.Type.DELETE_PROP) {
if (initialized) {
warnAboutNamespaceRedefinition(name, ref);
}
} else if (ref.type == Ref.Type.SET_FROM_GLOBAL || ref.type == Ref.Type.SET_FROM_LOCAL) {
if (initialized && !isSafeNamespaceReinit(ref)) {
warnAboutNamespaceRedefinition(name, ref);
}
initialized = true;
} else if (ref.type == Ref.Type.ALIASING_GET) {
warnAboutNamespaceAliasing(name, ref);
}
}
}
}
}
/**
* @param name The Name whose properties references should be updated.
* @param value The value to use when rewriting.
* @param depth The chain depth.
* @param newNodes Expression nodes that have been updated.
*/
private static void rewriteAliasProps(Name name, Node value, int depth, Set<AstChange> newNodes) {
if (name.props == null) {
return;
}
Preconditions.checkState(!value.matchesQualifiedName(name.getFullName()));
for (Name prop : name.props) {
rewriteAliasProps(prop, value, depth + 1, newNodes);
List<Ref> refs = new ArrayList<>(prop.getRefs());
for (Ref ref : refs) {
Node target = ref.node;
for (int i = 0; i <= depth; i++) {
if (target.isGetProp()) {
target = target.getFirstChild();
} else if (NodeUtil.isObjectLitKey(target)) {
// Object literal key definitions are a little trickier, as we
// need to find the assignment target
Node gparent = target.getParent().getParent();
if (gparent.isAssign()) {
target = gparent.getFirstChild();
} else {
Preconditions.checkState(NodeUtil.isObjectLitKey(gparent));
target = gparent;
}
} else {
throw new IllegalStateException("unexpected: " + target);
}
}
Preconditions.checkState(target.isGetProp() || target.isName());
target.getParent().replaceChild(target, value.cloneTree());
prop.removeRef(ref);
// Rescan the expression root.
newNodes.add(new AstChange(ref.module, ref.scope, ref.node));
}
}
}
/**
* Adds global variable "stubs" for any properties of a global name that are only set in a local
* scope or read but never set.
*
* @param n An object representing a global name (e.g. "a", "a.b.c")
* @param alias The flattened name of the object whose properties we are adding stubs for (e.g.
* "a$b$c")
* @param parent The node to which new global variables should be added as children
* @param addAfter The child of after which new variables should be added
* @return The number of variables added
*/
private int addStubsForUndeclaredProperties(Name n, String alias, Node parent, Node addAfter) {
Preconditions.checkState(n.canCollapseUnannotatedChildNames());
Preconditions.checkArgument(NodeUtil.isStatementBlock(parent));
Preconditions.checkNotNull(addAfter);
if (n.props == null) {
return 0;
}
int numStubs = 0;
for (Name p : n.props) {
if (p.needsToBeStubbed()) {
String propAlias = appendPropForAlias(alias, p.getBaseName());
Node nameNode = IR.name(propAlias);
Node newVar = IR.var(nameNode).useSourceInfoIfMissingFromForTree(addAfter);
parent.addChildAfter(newVar, addAfter);
addAfter = newVar;
numStubs++;
compiler.reportCodeChange();
// Determine if this is a constant var by checking the first
// reference to it. Don't check the declaration, as it might be null.
if (p.getRefs().get(0).node.getLastChild().getBooleanProp(Node.IS_CONSTANT_NAME)) {
nameNode.putBooleanProp(Node.IS_CONSTANT_NAME, true);
}
}
}
return numStubs;
}
/** Flattens a stub declaration. This is mostly a hack to support legacy users. */
private void flattenSimpleStubDeclaration(Name name, String alias) {
Ref ref = Iterables.getOnlyElement(name.getRefs());
Node nameNode = NodeUtil.newName(compiler, alias, ref.node, name.getFullName());
Node varNode = IR.var(nameNode).useSourceInfoIfMissingFrom(nameNode);
Preconditions.checkState(ref.node.getParent().isExprResult());
Node parent = ref.node.getParent();
Node grandparent = parent.getParent();
grandparent.replaceChild(parent, varNode);
compiler.reportCodeChange();
}
/**
* Attempt to inline an global alias of a global name. This requires that the name is well
* defined: assigned unconditionally, assigned exactly once. It is assumed that, the name for
* which it is an alias must already meet these same requirements.
*
* @param alias The alias to inline
* @return Whether the alias was inlined.
*/
private boolean inlineGlobalAliasIfPossible(Name name, Ref alias, GlobalNamespace namespace) {
// Ensure that the alias is assigned to global name at that the
// declaration.
Node aliasParent = alias.node.getParent();
if (aliasParent.isAssign() && NodeUtil.isExecutedExactlyOnce(aliasParent)
// We special-case for constructors here, to inline constructor aliases
// more aggressively in global scope.
// We do this because constructor properties are always collapsed,
// so we want to inline the aliases also to avoid breakages.
|| aliasParent.isName() && name.isConstructor()) {
Node lvalue = aliasParent.isName() ? aliasParent : aliasParent.getFirstChild();
if (!lvalue.isQualifiedName()) {
return false;
}
name = namespace.getSlot(lvalue.getQualifiedName());
if (name != null && name.isInlinableGlobalAlias()) {
Set<AstChange> newNodes = new LinkedHashSet<>();
List<Ref> refs = new ArrayList<>(name.getRefs());
for (Ref ref : refs) {
switch (ref.type) {
case SET_FROM_GLOBAL:
continue;
case DIRECT_GET:
case ALIASING_GET:
Node newNode = alias.node.cloneTree();
Node node = ref.node;
node.getParent().replaceChild(node, newNode);
newNodes.add(new AstChange(ref.module, ref.scope, newNode));
name.removeRef(ref);
break;
default:
throw new IllegalStateException();
}
}
rewriteAliasProps(name, alias.node, 0, newNodes);
// just set the original alias to null.
aliasParent.replaceChild(alias.node, IR.nullNode());
compiler.reportCodeChange();
// Inlining the variable may have introduced new references
// to descendants of {@code name}. So those need to be collected now.
namespace.scanNewNodes(newNodes);
return true;
}
}
return false;
}
/**
* For each qualified name N in the global scope, we check if: (a) No ancestor of N is ever
* aliased or assigned an unknown value type. (If N = "a.b.c", "a" and "a.b" are never aliased).
* (b) N has exactly one write, and it lives in the global scope. (c) N is aliased in a local
* scope. (d) N is aliased in global scope
*
* <p>If (a) is true, then GlobalNamespace must know all the writes to N. If (a) and (b) are true,
* then N cannot change during the execution of a local scope. If (a) and (b) and (c) are true,
* then the alias can be inlined if the alias obeys the usual rules for how we decide whether a
* variable is inlineable. If (a) and (b) and (d) are true, then inline the alias if possible (if
* it is assigned exactly once unconditionally).
*
* @see InlineVariables
*/
private void inlineAliases(GlobalNamespace namespace) {
// Invariant: All the names in the worklist meet condition (a).
Deque<Name> workList = new ArrayDeque<>(namespace.getNameForest());
while (!workList.isEmpty()) {
Name name = workList.pop();
// Don't attempt to inline a getter or setter property as a variable.
if (name.type == Name.Type.GET || name.type == Name.Type.SET) {
continue;
}
if (!name.inExterns && name.globalSets == 1 && name.localSets == 0 && name.aliasingGets > 0) {
// {@code name} meets condition (b). Find all of its local aliases
// and try to inline them.
List<Ref> refs = new ArrayList<>(name.getRefs());
for (Ref ref : refs) {
if (ref.type == Type.ALIASING_GET && ref.scope.isLocal()) {
// {@code name} meets condition (c). Try to inline it.
// TODO(johnlenz): consider picking up new aliases at the end
// of the pass instead of immediately like we do for global
// inlines.
if (inlineAliasIfPossible(name, ref, namespace)) {
name.removeRef(ref);
}
} else if (ref.type == Type.ALIASING_GET
&& ref.scope.isGlobal()
&& ref.getTwin() == null) { // ignore aliases in chained assignments
if (inlineGlobalAliasIfPossible(name, ref, namespace)) {
name.removeRef(ref);
}
}
}
}
// Check if {@code name} has any aliases left after the
// local-alias-inlining above.
if ((name.type == Name.Type.OBJECTLIT || name.type == Name.Type.FUNCTION)
&& name.aliasingGets == 0
&& name.props != null) {
// All of {@code name}'s children meet condition (a), so they can be
// added to the worklist.
workList.addAll(name.props);
}
}
}
/**
* Extracts all Behaviors from an array recursively. The array must be an array literal whose
* value is known at compile-time. Entries in the array can be object literals or array literals
* (of other behaviors). Behavior names must be global, fully qualified names.
*
* @see https://github.com/Polymer/polymer/blob/0.8-preview/PRIMER.md#behaviors
* @return A list of all {@code BehaviorDefinitions} in the array.
*/
private List<BehaviorDefinition> extractBehaviors(Node behaviorArray) {
if (behaviorArray == null) {
return ImmutableList.of();
}
if (!behaviorArray.isArrayLit()) {
compiler.report(JSError.make(behaviorArray, POLYMER_INVALID_BEHAVIOR_ARRAY));
return ImmutableList.of();
}
ImmutableList.Builder<BehaviorDefinition> behaviors = ImmutableList.builder();
for (Node behaviorName : behaviorArray.children()) {
if (behaviorName.isObjectLit()) {
this.switchDollarSignPropsToBrackets(behaviorName);
this.quoteListenerAndHostAttributeKeys(behaviorName);
behaviors.add(
new BehaviorDefinition(
extractProperties(behaviorName),
getBehaviorFunctionsToCopy(behaviorName),
getNonPropertyMembersToCopy(behaviorName),
!NodeUtil.isInFunction(behaviorName)));
continue;
}
Name behaviorGlobalName = globalNames.getSlot(behaviorName.getQualifiedName());
boolean isGlobalDeclaration = true;
if (behaviorGlobalName == null) {
compiler.report(JSError.make(behaviorName, POLYMER_UNQUALIFIED_BEHAVIOR));
continue;
}
Ref behaviorDeclaration = behaviorGlobalName.getDeclaration();
// Use any set as a backup declaration, even if it's local.
if (behaviorDeclaration == null) {
List<Ref> behaviorRefs = behaviorGlobalName.getRefs();
for (Ref ref : behaviorRefs) {
if (ref.isSet()) {
isGlobalDeclaration = false;
behaviorDeclaration = ref;
break;
}
}
}
if (behaviorDeclaration == null) {
compiler.report(JSError.make(behaviorName, POLYMER_UNQUALIFIED_BEHAVIOR));
continue;
}
Node behaviorDeclarationNode = behaviorDeclaration.getNode();
JSDocInfo behaviorInfo = NodeUtil.getBestJSDocInfo(behaviorDeclarationNode);
if (behaviorInfo == null || !behaviorInfo.isPolymerBehavior()) {
compiler.report(JSError.make(behaviorDeclarationNode, POLYMER_UNANNOTATED_BEHAVIOR));
}
Node behaviorValue = NodeUtil.getRValueOfLValue(behaviorDeclarationNode);
if (behaviorValue == null) {
compiler.report(JSError.make(behaviorName, POLYMER_UNQUALIFIED_BEHAVIOR));
} else if (behaviorValue.isArrayLit()) {
// Individual behaviors can also be arrays of behaviors. Parse them recursively.
behaviors.addAll(extractBehaviors(behaviorValue));
} else if (behaviorValue.isObjectLit()) {
this.switchDollarSignPropsToBrackets(behaviorValue);
this.quoteListenerAndHostAttributeKeys(behaviorValue);
behaviors.add(
new BehaviorDefinition(
extractProperties(behaviorValue),
getBehaviorFunctionsToCopy(behaviorValue),
getNonPropertyMembersToCopy(behaviorValue),
isGlobalDeclaration));
} else {
compiler.report(JSError.make(behaviorName, POLYMER_UNQUALIFIED_BEHAVIOR));
}
}
return behaviors.build();
}