@Override
public void process(Node externs, Node root) {
assignmentLog = new StringBuilder();
// Do variable reference counting.
NodeTraversal.traverse(compiler, externs, new ProcessVars(true));
NodeTraversal.traverse(compiler, root, new ProcessVars(false));
// Make sure that new names don't overlap with extern names.
reservedNames.addAll(externNames);
// Rename vars, sorted by frequency of occurrence to minimize code size.
SortedSet<Assignment> varsByFrequency = new TreeSet<Assignment>(FREQUENCY_COMPARATOR);
varsByFrequency.addAll(assignments.values());
if (shouldShadow) {
new ShadowVariables(compiler, assignments, varsByFrequency, pseudoNameMap)
.process(externs, root);
}
// First try to reuse names from an earlier compilation.
if (prevUsedRenameMap != null) {
reusePreviouslyUsedVariableMap();
}
// Assign names, sorted by descending frequency to minimize code size.
assignNames(varsByFrequency);
boolean changed = false;
// Rename the globals!
for (Node n : globalNameNodes) {
String newName = getNewGlobalName(n);
// Note: if newName is null, then oldName is an extern.
if (newName != null) {
n.setString(newName);
changed = true;
}
}
// Rename the locals!
int count = 0;
for (Node n : localNameNodes) {
String newName = getNewLocalName(n);
if (newName != null) {
n.setString(newName);
changed = true;
}
count++;
}
if (changed) {
compiler.reportCodeChange();
}
// Lastly, write the name assignments to the debug log.
compiler.addToDebugLog("JS var assignments:\n" + assignmentLog);
assignmentLog = null;
}
/**
* Removes any vars in the scope that were not referenced. Removes any assignments to those
* variables as well.
*/
private void removeUnreferencedVars() {
CodingConvention convention = codingConvention;
for (Iterator<Var> it = maybeUnreferenced.iterator(); it.hasNext(); ) {
Var var = it.next();
// Remove calls to inheritance-defining functions where the unreferenced
// class is the subclass.
for (Node exprCallNode : inheritsCalls.get(var)) {
NodeUtil.removeChild(exprCallNode.getParent(), exprCallNode);
compiler.reportCodeChange();
}
// Regardless of what happens to the original declaration,
// we need to remove all assigns, because they may contain references
// to other unreferenced variables.
removeAllAssigns(var);
compiler.addToDebugLog("Unreferenced var: " + var.name);
Node nameNode = var.nameNode;
Node toRemove = nameNode.getParent();
Node parent = toRemove.getParent();
Preconditions.checkState(
toRemove.getType() == Token.VAR
|| toRemove.getType() == Token.FUNCTION
|| toRemove.getType() == Token.LP && parent.getType() == Token.FUNCTION,
"We should only declare vars and functions and function args");
if (toRemove.getType() == Token.LP && parent.getType() == Token.FUNCTION) {
// Don't remove function arguments here. That's a special case
// that's taken care of in removeUnreferencedFunctionArgs.
} else if (NodeUtil.isFunctionExpression(toRemove)) {
if (!preserveFunctionExpressionNames) {
toRemove.getFirstChild().setString("");
compiler.reportCodeChange();
}
// Don't remove bleeding functions.
} else if (parent != null && parent.getType() == Token.FOR && parent.getChildCount() < 4) {
// foreach iterations have 3 children. Leave them alone.
} else if (toRemove.getType() == Token.VAR
&& nameNode.hasChildren()
&& NodeUtil.mayHaveSideEffects(nameNode.getFirstChild())) {
// If this is a single var declaration, we can at least remove the
// declaration itself and just leave the value, e.g.,
// var a = foo(); => foo();
if (toRemove.getChildCount() == 1) {
parent.replaceChild(toRemove, new Node(Token.EXPR_RESULT, nameNode.removeFirstChild()));
compiler.reportCodeChange();
}
} else if (toRemove.getType() == Token.VAR && toRemove.getChildCount() > 1) {
// For var declarations with multiple names (i.e. var a, b, c),
// only remove the unreferenced name
toRemove.removeChild(nameNode);
compiler.reportCodeChange();
} else if (parent != null) {
NodeUtil.removeChild(parent, toRemove);
compiler.reportCodeChange();
}
}
}
