@Override
public String get() {
return nameGenerator.generateNextName();
}
/** Determines which new names to substitute for the original names. */
private void assignNames(Set<Assignment> varsToRename) {
NameGenerator globalNameGenerator =
new NameGenerator(reservedNames, prefix, reservedCharacters);
// Local variables never need a prefix.
NameGenerator localNameGenerator =
prefix.isEmpty()
? globalNameGenerator
: new NameGenerator(reservedNames, "", reservedCharacters);
// Generated names and the assignments for non-local vars.
List<Assignment> pendingAssignments = new ArrayList<Assignment>();
List<String> generatedNamesForAssignments = new ArrayList<String>();
for (Assignment a : varsToRename) {
if (a.newName != null) {
continue;
}
if (externNames.contains(a.oldName)) {
continue;
}
String newName;
if (a.oldName.startsWith(LOCAL_VAR_PREFIX)) {
// For local variable, we make the assignment right away.
newName = localNameGenerator.generateNextName();
finalizeNameAssignment(a, newName);
} else {
// For non-local variable, delay finalizing the name assignment
// until we know how many new names we'll have of length 2, 3, etc.
newName = globalNameGenerator.generateNextName();
pendingAssignments.add(a);
generatedNamesForAssignments.add(newName);
}
reservedNames.add(newName);
}
// Now that we have a list of generated names, and a list of variable
// Assignment objects, we assign the generated names to the vars as
// follows:
// 1) The most frequent vars get the shorter names.
// 2) If N number of vars are going to be assigned names of the same
// length, we assign the N names based on the order at which the vars
// first appear in the source. This makes the output somewhat less
// random, because symbols declared close together are assigned names
// that are quite similar. With this heuristic, the output is more
// compressible.
// For instance, the output may look like:
// var da = "..", ea = "..";
// function fa() { .. } function ga() { .. }
int numPendingAssignments = generatedNamesForAssignments.size();
for (int i = 0; i < numPendingAssignments; ) {
SortedSet<Assignment> varsByOrderOfOccurrence =
new TreeSet<Assignment>(ORDER_OF_OCCURRENCE_COMPARATOR);
// Add k number of Assignment to the set, where k is the number of
// generated names of the same length.
int len = generatedNamesForAssignments.get(i).length();
for (int j = i;
j < numPendingAssignments && generatedNamesForAssignments.get(j).length() == len;
j++) {
varsByOrderOfOccurrence.add(pendingAssignments.get(j));
}
// Now, make the assignments
for (Assignment a : varsByOrderOfOccurrence) {
finalizeNameAssignment(a, generatedNamesForAssignments.get(i));
++i;
}
}
}
