@NotNull
public static Nullness checkNullness(
@Nullable final PsiVariable variable, @Nullable final PsiElement context) {
if (variable == null || context == null) return Nullness.UNKNOWN;
final PsiElement codeBlock = DfaPsiUtil.getEnclosingCodeBlock(variable, context);
if (codeBlock == null) {
return Nullness.UNKNOWN;
}
final ValuableInstructionVisitor visitor = new ValuableInstructionVisitor(context);
RunnerResult result = new ValuableDataFlowRunner().analyzeMethod(codeBlock, visitor);
if (result != RunnerResult.OK) {
return Nullness.UNKNOWN;
}
if (visitor.myNulls.contains(variable) && !visitor.myNotNulls.contains(variable))
return Nullness.NULLABLE;
if (visitor.myNotNulls.contains(variable) && !visitor.myNulls.contains(variable))
return Nullness.NOT_NULL;
return Nullness.UNKNOWN;
}
@Nullable("null means DFA analysis has failed (too complex to analyze)")
public static Collection<PsiExpression> getCachedVariableValues(
@Nullable final PsiVariable variable, @Nullable final PsiElement context) {
if (variable == null || context == null) return Collections.emptyList();
CachedValue<MultiValuesMap<PsiVariable, PsiExpression>> cachedValue =
context.getUserData(DFA_VARIABLE_INFO_KEY);
if (cachedValue == null) {
final PsiElement codeBlock = DfaPsiUtil.getEnclosingCodeBlock(variable, context);
cachedValue =
CachedValuesManager.getManager(context.getProject())
.createCachedValue(
new CachedValueProvider<MultiValuesMap<PsiVariable, PsiExpression>>() {
@Override
public Result<MultiValuesMap<PsiVariable, PsiExpression>> compute() {
final MultiValuesMap<PsiVariable, PsiExpression> result;
if (codeBlock == null) {
result = null;
} else {
final ValuableInstructionVisitor visitor =
new ValuableInstructionVisitor(context);
RunnerResult runnerResult =
new ValuableDataFlowRunner().analyzeMethod(codeBlock, visitor);
if (runnerResult == RunnerResult.OK) {
result = visitor.myValues;
} else {
result = TOO_COMPLEX;
}
}
return new Result<MultiValuesMap<PsiVariable, PsiExpression>>(
result, variable);
}
},
false);
context.putUserData(DFA_VARIABLE_INFO_KEY, cachedValue);
}
final MultiValuesMap<PsiVariable, PsiExpression> value = cachedValue.getValue();
if (value == TOO_COMPLEX) return null;
final Collection<PsiExpression> expressions = value == null ? null : value.get(variable);
return expressions == null ? Collections.<PsiExpression>emptyList() : expressions;
}