/**
* Returns a sequence that creates an object of type compatible the given class. Wraps the object
* in a list, and returns the list.
*
* <p>CURRENTLY, will return a sequence (i.e. a non-empty list) only if cls is an array.
*/
public static SimpleList<Sequence> createSequence(ComponentManager components, Class<?> cls) {
// Class<?> cls = statement.getInputTypes().get(i);
if (!cls.isArray()) {
return new ArrayListSimpleList<Sequence>();
}
Sequence s = null;
if (cls.getComponentType().isPrimitive()) {
s = randPrimitiveArray(cls.getComponentType());
} else {
SimpleList<Sequence> candidates =
components.getSequencesForType(cls.getComponentType(), false);
if (candidates.isEmpty()) {
if (GenInputsAbstract.forbid_null) {
// No sequences that produce appropriate component values found, and null forbidden.
// Return the empty array.
ArrayDeclaration decl = new ArrayDeclaration(cls.getComponentType(), 0);
s = new Sequence();
s = s.extend(decl);
} else {
// No sequences that produce appropriate component values found, and null allowed.
// TODO: We should also randomly return the empty array--it's a perfectly good case
// even if null is allowed.
// Return the array [ null ].
ArrayDeclaration decl = new ArrayDeclaration(cls.getComponentType(), 1);
s = new Sequence();
s = s.extend(PrimitiveOrStringOrNullDecl.nullOrZeroDecl(cls.getComponentType()));
List<Variable> ins = new ArrayList<Variable>();
ins.add(s.getVariable(0));
s = s.extend(decl, ins);
}
} else {
// Return the array [ x ] where x is the last value in the sequence.
ArrayDeclaration decl = new ArrayDeclaration(cls.getComponentType(), 1);
s = candidates.get(Randomness.nextRandomInt(candidates.size()));
List<Variable> ins = new ArrayList<Variable>();
// XXX IS THIS OLD COMMENT TRUE? : this assumes that last statement will have such a var,
// which I know is currently true because of SequenceCollection implementation.
ins.add(
s.randomVariableForTypeLastStatement(cls.getComponentType(), Match.COMPATIBLE_TYPE));
s = s.extend(decl, ins);
}
}
assert s != null;
ArrayListSimpleList<Sequence> l = new ArrayListSimpleList<Sequence>();
l.add(s);
return l;
}
// This method is responsible for doing two things:
//
// 1. Selecting at random a collection of sequences that can be used to
// create input values for the given statement, and
//
// 2. Selecting at random valid indices to the above sequence specifying
// the values to be used as input to the statement.
//
// The selected sequences and indices are wrapped in an InputsAndSuccessFlag
// object and returned. If an appropriate collection of sequences and indices
// was not found (e.g. because there are no sequences in the componentManager
// that create values of some type required by the statement), the success flag
// of the returned object is false.
@SuppressWarnings("unchecked")
private InputsAndSuccessFlag selectInputs(StatementKind statement) {
Tracer.trace("selectInputs");
// Variable inputTypes containsthe values required as input to the
// statement given as a parameter to the selectInputs method.
List<Class<?>> inputTypes = statement.getInputTypes();
// The rest of the code in this method will attempt to create
// a sequence that creates at least one value of type T for
// every type T in inputTypes, and thus can be used to create all the
// inputs for the statement.
// We denote this goal sequence as "S". We don't create S explicitly, but
// define it as the concatenation of the following list of sequences.
// In other words, S = sequences[0] + ... + sequences[sequences.size()-1].
// (This representation choice is for efficiency: it is cheaper to perform
// a single concatenation of the subsequences in the end than repeatedly
// extending S.)
List<Sequence> sequences = new ArrayList<Sequence>();
// We store the total size of S in the following variable.
int totStatements = 0;
// The method also returns a list of randomly-selected variables to
// be used as inputs to the statement, represented as indices into S.
// For example, given as statement a method M(T1)/T2 that takes as input
// a value of type T1 and returns a value of type T2, this method might
// return, for example, the sequence
//
// T0 var0 = new T0(); T1 var1 = var0.getT1()"
//
// and the singleton list [0] that represents variable var1. The variable
// indices are stored in the following list. Upon successful completion
// of this method, variables will contain inputTypes.size() variables.
// Note additionally that for every i in variables, 0 <= i < |S|.
List<Integer> variables = new ArrayList<Integer>();
// [Optimization]
// The following two variables are used in the loop below only when
// an alias ratio is present (GenInputsAbstract.alias_ratio != null).
// Their purpose is purely to improve efficiency. For a given loop iteration
// i, "types" contains the types of all variables in S, and "typesToVars"
// maps each type to all variable indices of the given type.
SubTypeSet types = new SubTypeSet(false);
MultiMap<Class<?>, Integer> typesToVars = new MultiMap<Class<?>, Integer>();
for (int i = 0; i < inputTypes.size(); i++) {
Class<?> t = inputTypes.get(i);
// TODO Does this ever happen?
if (!Reflection.isVisible(t)) return new InputsAndSuccessFlag(false, null, null);
// true if statement st represents an instance method, and we are currently
// selecting a value to act as the receiver for the method.
boolean isReceiver =
(i == 0 && (statement instanceof RMethod) && (!((RMethod) statement).isStatic()));
// If alias ratio is given, attempt with some probability to use a variable already in S.
if (GenInputsAbstract.alias_ratio != 0
&& Randomness.weighedCoinFlip(GenInputsAbstract.alias_ratio)) {
Tracer.trace("alias_ratio@selectInputs");
// candidateVars will store the indices that can serve as input to the i-th input in st.
List<SimpleList<Integer>> candidateVars = new ArrayList<SimpleList<Integer>>();
// For each type T in S compatible with inputTypes[i], add all the indices in S of type T.
for (Class<?> match : types.getMatches(t)) {
// Sanity check: the domain of typesToVars contains all the types in variable types.
assert typesToVars.keySet().contains(match);
candidateVars.add(
new ArrayListSimpleList<Integer>(
new ArrayList<Integer>(typesToVars.getValues(match))));
}
// If any type-compatible variables found, pick one at random as the i-th input to st.
SimpleList<Integer> candidateVars2 = new ListOfLists<Integer>(candidateVars);
if (candidateVars2.size() > 0) {
int randVarIdx = Randomness.nextRandomInt(candidateVars2.size());
Integer randVar = candidateVars2.get(randVarIdx);
variables.add(randVar);
continue;
}
}
Tracer.trace("NO alias_ratio@selectInputs");
// If we got here, it means we will not attempt to use a value already defined in S,
// so we will have to augment S with new statements that yield a value of type inputTypes[i].
// We will do this by assembling a list of candidate sequences n(stored in the list declared
// immediately below) that create one or more values of the appropriate type,
// randomly selecting a single sequence from this list, and appending it to S.
SimpleList<Sequence> l = null;
// We use one of three ways to gather candidate sequences, but the third case below
// is by far the most common.
if (GenInputsAbstract.always_use_ints_as_objects && t.equals(Object.class)) {
Tracer.trace("always_use_ints_as_objects@selectInputs");
// 1. OBSCURE, applicable only for branch-directed generation project. Get all
// sequences that create one or more integer. Applicable only when inputTypes[i]
// is "Object" and always_use_ints_as_objects option is specified.
if (Log.isLoggingOn()) Log.logLine("Integer-as-object heuristic: will use random Integer.");
l = componentManager.getSequencesForType(int.class, false);
} else if (t.isArray()) {
// 2. If T=inputTypes[i] is an array type, ask the component manager for all sequences
// of type T (list l1), but also try to directly build some sequences that create arrays
// (list l2).
SimpleList<Sequence> l1 = componentManager.getSequencesForType(statement, i);
if (Log.isLoggingOn())
Log.logLine("Array creation heuristic: will create helper array of type " + t);
SimpleList<Sequence> l2 = HelperSequenceCreator.createSequence(componentManager, t);
l = new ListOfLists<Sequence>(l1, l2);
} else {
// 3. COMMON CASE: ask the component manager for all sequences that yield the required type.
if (Log.isLoggingOn()) Log.logLine("Will query component set for objects of type" + t);
l = componentManager.getSequencesForType(statement, i);
}
assert l != null;
if (Log.isLoggingOn()) Log.logLine("components: " + l.size());
// If we were not able to find (or create) any sequences of type inputTypes[i], and we are
// allowed the use null values, use null. If we're not allowed, then return with failure.
if (l.size() == 0) {
Tracer.trace("selectinputs-evalforbid");
if (isReceiver || GenInputsAbstract.forbid_null) {
if (!isReceiver) {
if (GenInputsAbstract.forbid_null) {
Tracer.trace("forbid_null@selectinputs-evalforbid");
}
}
if (Log.isLoggingOn())
Log.logLine("forbid-null option is true. Failed to create new sequence.");
return new InputsAndSuccessFlag(false, null, null);
} else {
if (!GenInputsAbstract.forbid_null) {
Tracer.trace("NOT forbid_null@selectinputs-evalforbid");
}
if (Log.isLoggingOn()) Log.logLine("Will use null as " + i + "-th input");
StatementKind st = PrimitiveOrStringOrNullDecl.nullOrZeroDecl(t);
Sequence seq = new Sequence().extend(st, new ArrayList<Variable>());
variables.add(totStatements);
sequences.add(seq);
assert seq.size() == 1;
totStatements++;
// Null is not an interesting value to add to the set of
// possible values to reuse, so we don't update typesToVars or types.
continue;
}
}
// At this point, we have one or more sequences that create non-null values of type
// inputTypes[i].
// However, the user may have requested that we use null values as inputs with some given
// frequency.
// If this is the case, then use null instead with some probability.
Tracer.trace("selectinputs-null-ratio");
if (!isReceiver
&& GenInputsAbstract.null_ratio != 0
&& Randomness.weighedCoinFlip(GenInputsAbstract.null_ratio)) {
Tracer.trace("null_ratio@selectinputs-null-ratio");
if (Log.isLoggingOn())
Log.logLine("null-ratio option given. Randomly decided to use null as input.");
StatementKind st = PrimitiveOrStringOrNullDecl.nullOrZeroDecl(t);
Sequence seq = new Sequence().extend(st, new ArrayList<Variable>());
variables.add(totStatements);
sequences.add(seq);
assert seq.size() == 1;
totStatements++;
continue;
}
Tracer.trace("NOT null_ratio@selectinputs-null-ratio");
// At this point, we have a list of candidate sequences and need to select a
// randomly-chosen sequence from the list.
Sequence chosenSeq = null;
Tracer.trace("selectInputs-smalltests");
if (GenInputsAbstract.small_tests) {
Tracer.trace("small_tests@selectInputs-smalltests");
chosenSeq = Randomness.randomMemberWeighted(l);
} else {
Tracer.trace("NO small_tests@selectInputs-smalltests");
chosenSeq = Randomness.randomMember(l);
}
// Now, find values that satisfy the constraint set.
Match m = Match.COMPATIBLE_TYPE;
// if (i == 0 && statement.isInstanceMethod()) m = Match.EXACT_TYPE;
Variable randomVariable = chosenSeq.randomVariableForTypeLastStatement(t, m);
// We are not done yet: we have chosen a sequence that yields a value of the required
// type inputTypes[i], but there may be more than one such value. Our last random
// selection step is to select from among all possible values.
// if (i == 0 && statement.isInstanceMethod()) m = Match.EXACT_TYPE;
if (randomVariable == null) {
throw new BugInRandoopException("type: " + t + ", sequence: " + chosenSeq);
}
// If we were unlucky and selected a null value as the receiver
// for a method call, return with failure.
if (i == 0
&& (statement instanceof RMethod)
&& (!((RMethod) statement).isStatic())
&& chosenSeq.getCreatingStatement(randomVariable) instanceof PrimitiveOrStringOrNullDecl)
return new InputsAndSuccessFlag(false, null, null);
// [Optimization.] Update optimization-related variables "types" and "typesToVars".
Tracer.trace("selectinputs-alias");
if (GenInputsAbstract.alias_ratio != 0) {
Tracer.trace("alias_ratio@selectinputs-alias");
// Update types and typesToVars.
for (int j = 0; j < chosenSeq.size(); j++) {
StatementKind stk = chosenSeq.getStatementKind(j);
if (stk instanceof PrimitiveOrStringOrNullDecl)
continue; // Prim decl not an interesting candidate for multiple uses.
Class<?> outType = stk.getOutputType();
types.add(outType);
typesToVars.add(outType, totStatements + j);
}
}
Tracer.trace("NOT alias_ratio@selectinputs-alias");
variables.add(totStatements + randomVariable.index);
sequences.add(chosenSeq);
totStatements += chosenSeq.size();
}
return new InputsAndSuccessFlag(true, sequences, variables);
}
