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package chapter;
import java.util.concurrent.locks.ReentrantLock;
import org.checkerframework.checker.lock.qual.GuardedBy;
import org.checkerframework.checker.lock.qual.GuardedByUnknown;
import org.checkerframework.checker.lock.qual.MayReleaseLocks;
import org.checkerframework.dataflow.qual.Deterministic;
import org.checkerframework.dataflow.qual.Pure;
public class LockExpressionIsFinal {
class MyClass {
Object field = new Object();
}
class C1 {
final C1 field =
new C1(); // Infinite loop. This code is not meant to be executed, only type
// checked.
C1 field2;
@Deterministic
C1 getFieldDeterministic() {
return field;
}
@Pure
C1 getFieldPure(Object param1, Object param2) {
return field;
}
@Pure
C1 getFieldPure2() {
return field;
}
C1 getField() {
return field;
}
}
final C1 c1 = new C1();
// Analogous to testExplicitLockExpressionIsFinal and testGuardedByExpressionIsFinal, but for
// monitor locks acquired in synchronized blocks.
void testSynchronizedExpressionIsFinal(boolean b) {
synchronized (c1) {
}
Object o1 = new Object(); // o1 is effectively final - it is never reassigned
Object o2 = new Object(); // o2 is reassigned later - it is not effectively final
synchronized (o1) {
}
// :: error: (lock.expression.not.final)
synchronized (o2) {
}
o2 = new Object(); // Reassignment that makes o2 not have been effectively final earlier.
// Tests that package names are considered final.
synchronized (java.lang.String.class) {
}
// Test a tree that is not supported by LockVisitor.ensureExpressionIsEffectivelyFinal
// :: error: (lock.expression.possibly.not.final)
synchronized (c1.getFieldPure(b ? c1 : o1, c1)) {
}
synchronized (
c1.field.field.field.getFieldPure(
c1.field, c1.getFieldDeterministic().getFieldPure(c1, c1.field))
.field) {
}
// The following negative test cases are the same as the one above but with one modification
// in each.
synchronized (
// :: error: (lock.expression.not.final)
c1.field.field2.field.getFieldPure(
c1.field, c1.getFieldDeterministic().getFieldPure(c1, c1.field))
.field) {
}
synchronized (
c1.field.field.field.getFieldPure(
// :: error: (lock.expression.not.final)
c1.field, c1.getField().getFieldPure(c1, c1.field))
.field) {
}
}
class C2 extends ReentrantLock {
final C2 field =
new C2(); // Infinite loop. The code is not meant to be executed, only type-checked.
C2 field2;
@Deterministic
C2 getFieldDeterministic() {
return field;
}
@Pure
C2 getFieldPure(Object param1, Object param2) {
return field;
}
C2 getField() {
return field;
}
}
final C2 c2 = new C2();
// Analogous to testSynchronizedExpressionIsFinal and testGuardedByExpressionIsFinal, but for
// explicit locks.
@MayReleaseLocks
void testExplicitLockExpressionIsFinal(boolean b) {
c2.lock();
ReentrantLock rl1 =
new ReentrantLock(); // rl1 is effectively final - it is never reassigned
ReentrantLock rl2 =
new ReentrantLock(); // rl2 is reassigned later - it is not effectively final
rl1.lock();
rl1.unlock();
// :: error: (lock.expression.not.final)
rl2.lock();
// :: error: (lock.expression.not.final)
rl2.unlock();
rl2 = new ReentrantLock(); // Reassignment that makes rl2 not have been effectively final
// earlier.
// Test a tree that is not supported by LockVisitor.ensureExpressionIsEffectivelyFinal
// :: error: (lock.expression.possibly.not.final)
c2.getFieldPure(b ? c2 : rl1, c2).lock();
// :: error: (lock.expression.possibly.not.final)
c2.getFieldPure(b ? c2 : rl1, c2).unlock();
c2.field
.field
.field
.getFieldPure(c2.field, c2.getFieldDeterministic().getFieldPure(c2, c2.field))
.field
.lock();
c2.field
.field
.field
.getFieldPure(c2.field, c2.getFieldDeterministic().getFieldPure(c2, c2.field))
.field
.unlock();
// The following negative test cases are the same as the one above but with one modification
// in each.
c2.field
// :: error: (lock.expression.not.final)
.field2
.field
.getFieldPure(c2.field, c2.getFieldDeterministic().getFieldPure(c2, c2.field))
.field
.lock();
c2.field
// :: error: (lock.expression.not.final)
.field2
.field
.getFieldPure(c2.field, c2.getFieldDeterministic().getFieldPure(c2, c2.field))
.field
.unlock();
c2.field
.field
.field
// :: error: (lock.expression.not.final)
.getFieldPure(c2.field, c2.getField().getFieldPure(c2, c2.field))
.field
.lock();
c2.field
.field
.field
// :: error: (lock.expression.not.final)
.getFieldPure(c2.field, c2.getField().getFieldPure(c2, c2.field))
.field
.unlock();
}
// Analogous to testSynchronizedExpressionIsFinal and testExplicitLockExpressionIsFinal, but for
// expressions in @GuardedBy annotations.
void testGuardedByExpressionIsFinal() {
@GuardedBy("c1") Object guarded1;
final Object o1 = new Object();
Object o2 = new Object();
// reassign so it's not effectively final
o2 = new Object();
@GuardedBy("o1") Object guarded2 = new Object();
// :: error: (lock.expression.not.final)
@GuardedBy("o2") Object guarded3 = new Object();
// Test expressions that are not supported by LockVisitor.ensureExpressionIsEffectivelyFinal
@GuardedBy("java.lang.String.class") Object guarded4;
// :: error: (expression.unparsable.type.invalid)
@GuardedBy("c1.getFieldPure(b ? c1 : o1, c1)") Object guarded5;
@GuardedBy(
"c1.field.field.field.getFieldPure(c1.field, c1.getFieldDeterministic().getFieldPure(c1, c1.field)).field")
Object guarded6;
@GuardedBy("c1.field.field.field.getFieldPure2().getFieldDeterministic().field") Object guarded7;
// The following negative test cases are the same as the one above but with one modification
// in each.
// :: error: (lock.expression.not.final)
@GuardedBy("c1.field.field2.field.getFieldPure2().getFieldDeterministic().field") Object guarded8;
// :: error: (lock.expression.not.final)
@GuardedBy("c1.field.field.field.getField().getFieldDeterministic().field") Object guarded9;
// Additional test cases to test that method parameters (in this case the parameters to
// getFieldPure) are parsed.
@GuardedBy("c1.field.field.field.getFieldPure(c1, c1).getFieldDeterministic().field") Object guarded10;
@GuardedBy("c1.field.field.field.getFieldPure(c1, o1).getFieldDeterministic().field") Object guarded11;
// :: error: (lock.expression.not.final)
@GuardedBy("c1.field.field.field.getFieldPure(c1, o2).getFieldDeterministic().field") Object guarded12;
// Test that @GuardedBy annotations on various tree kinds inside a method are visited
Object guarded13 = (@GuardedBy("o1") Object) guarded2;
// :: error: (lock.expression.not.final)
Object guarded14 = (@GuardedBy("o2") Object) guarded3;
Object guarded15[] = new @GuardedBy("o1") MyClass[3];
// :: error: (lock.expression.not.final)
Object guarded16[] = new @GuardedBy("o2") MyClass[3];
// Tests that the location of the @GB annotation inside a VariableTree does not matter (i.e.
// it does not need to be the leftmost subtree).
Object guarded17 @GuardedBy("o1") [];
// :: error: (lock.expression.not.final)
Object guarded18 @GuardedBy("o2") [];
@GuardedBy("o1") Object guarded19[];
// :: error: (lock.expression.not.final)
@GuardedBy("o2") Object guarded20[];
MyParameterizedClass1<@GuardedBy("o1") Object> m1;
// :: error: (lock.expression.not.final)
MyParameterizedClass1<@GuardedBy("o2") Object> m2;
boolean b = c1 instanceof @GuardedBy("o1") Object;
// instanceof expression have not effect on the type.
// // :: error: (lock.expression.not.final)
b = c1 instanceof @GuardedBy("o2") Object;
// Additional tests just outside of this method below:
}
// Test that @GuardedBy annotations on various tree kinds outside a method are visited
// Test that @GuardedBy annotations on method return types are visited. No need to test method
// receivers and parameters as they are covered by tests above that visit VariableTree.
final Object finalField = new Object();
Object nonFinalField = new Object();
@GuardedBy("finalField") Object testGuardedByExprIsFinal1() {
return null;
}
// :: error: (lock.expression.not.final)
@GuardedBy("nonFinalField") Object testGuardedByExprIsFinal2() {
return null;
}
<T extends @GuardedBy("finalField") Object> T myMethodThatReturnsT_1(T t) {
return t;
}
// :: error: (lock.expression.not.final)
<T extends @GuardedBy("nonFinalField") Object> T myMethodThatReturnsT_2(T t) {
return t;
}
class MyParameterizedClass1<T extends @GuardedByUnknown Object> {};
MyParameterizedClass1<? super @GuardedBy("finalField") Object> m1;
// :: error: (lock.expression.not.final)
MyParameterizedClass1<? super @GuardedBy("nonFinalField") Object> m2;
MyParameterizedClass1<? extends @GuardedBy("finalField") Object> m3;
// :: error: (lock.expression.not.final)
MyParameterizedClass1<? extends @GuardedBy("nonFinalField") Object> m4;
class MyClassContainingALock {
final ReentrantLock finalLock = new ReentrantLock();
ReentrantLock nonFinalLock = new ReentrantLock();
Object field;
}
void testItselfFinalLock() {
final @GuardedBy("<self>.finalLock") MyClassContainingALock m =
new MyClassContainingALock();
// :: error: (lock.not.held)
m.field = new Object();
// Ignore this error: it is expected that an error will be issued for dereferencing 'm' in
// order to take the 'm.finalLock' lock. Typically, the Lock Checker does not support an
// object being guarded by one of its fields, but this is sometimes done in user code with a
// ReentrantLock field guarding its containing object. This unfortunately makes it a bit
// difficult for users since they have to add a @SuppressWarnings for this call while still
// making sure that warnings for other dereferences are not suppressed.
// :: error: (lock.not.held)
m.finalLock.lock();
m.field = new Object();
}
void testItselfNonFinalLock() {
final @GuardedBy("<self>.nonFinalLock") MyClassContainingALock m =
new MyClassContainingALock();
// ::error: (lock.not.held) :: error: (lock.expression.not.final)
m.field = new Object();
// ::error: (lock.not.held) :: error: (lock.expression.not.final)
m.nonFinalLock.lock();
// :: error: (lock.expression.not.final)
m.field = new Object();
}
}
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