Change StdWeightedScheduler API (#712)

* change

* fmt

fuzzers/fuzzbench_weighted/src/lib.rs

@@ -318,9 +318,9 @@ fn fuzz(
     let power = StdPowerMutationalStage::new(mutator, &edges_observer);
 
     // A minimization+queue policy to get testcasess from the corpus
-    let scheduler = IndexesLenTimeMinimizerScheduler::new(StdWeightedScheduler::new(Some(
+    let scheduler = IndexesLenTimeMinimizerScheduler::new(StdWeightedScheduler::with_schedule(
         PowerSchedule::EXPLORE,
-    )));
+    ));
 
     // A fuzzer with feedbacks and a corpus scheduler
     let mut fuzzer = StdFuzzer::new(scheduler, feedback, objective);

fuzzers/libfuzzer_libpng/src/lib.rs

@@ -141,8 +141,9 @@ fn fuzz(corpus_dirs: &[PathBuf], objective_dir: PathBuf, broker_port: u16) -> Re
     let mut stages = tuple_list!(calibration, power);
 
     // A minimization+queue policy to get testcasess from the corpus
-    let scheduler =
+    let scheduler = IndexesLenTimeMinimizerScheduler::new(StdWeightedScheduler::with_schedule(
-        IndexesLenTimeMinimizerScheduler::new(StdWeightedScheduler::new(Some(PowerSchedule::FAST)));
+        PowerSchedule::FAST,
+    ));
 
     // A fuzzer with feedbacks and a corpus scheduler
     let mut fuzzer = StdFuzzer::new(scheduler, feedback, objective);

libafl/src/schedulers/weighted.rs

@@ -93,17 +93,37 @@ pub struct WeightedScheduler<F, I, S> {
     phantom: PhantomData<(F, I, S)>,
 }
 
+impl<F, I, S> Default for WeightedScheduler<F, I, S>
+where
+    F: TestcaseScore<I, S>,
+    I: Input,
+    S: HasCorpus<I> + HasMetadata + HasRand,
+{
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl<F, I, S> WeightedScheduler<F, I, S>
 where
     F: TestcaseScore<I, S>,
     I: Input,
     S: HasCorpus<I> + HasMetadata + HasRand,
 {
+    /// Create a new [`WeightedScheduler`] without any scheduling strategy
+    #[must_use]
+    pub fn new() -> Self {
+        Self {
+            strat: None,
+            phantom: PhantomData,
+        }
+    }
+
     /// Create a new [`WeightedScheduler`]
     #[must_use]
-    pub fn new(strat: Option<PowerSchedule>) -> Self {
+    pub fn with_schedule(strat: PowerSchedule) -> Self {
         Self {
-            strat,
+            strat: Some(strat),
             phantom: PhantomData,
         }
     }