error handling

src/corpus/mod.rs

@@ -117,7 +117,7 @@ impl<RandT: Rand> Corpus for QueueCorpus<'_, RandT> {
     /// Gets the next entry
     fn get(&mut self) -> Result<&Box<dyn Testcase>, AflError> {
         if self.count() == 0 {
-            return Err(AflError::Unknown); // TODO(andrea) why unknown? use EmptyContainerError or similar
+            return Err(AflError::Empty("Testcases".to_string()));
         }
         self.pos = self.pos + 1;
         if self.pos >= self.count() {
@@ -156,7 +156,7 @@ pub struct SimpleTestcase {
 impl Testcase for SimpleTestcase {
     fn load_input(&mut self) -> Result<&Box<dyn Input>, AflError> {
         // TODO: Implement
-        Err(AflError::Unknown)
+        Err(AflError::NotImplemented("load_input".to_string()))
     }
 
     fn is_on_disk(&self) -> bool {

src/executors/mod.rs

@@ -124,7 +124,7 @@ impl Executor for InMemoryExecutor {
     fn run_target(&mut self) -> Result<ExitKind, AflError> {
         let bytes = match self.base.cur_input.as_ref() {
             Some(i) => i.serialize(),
-            None => return Err(AflError::Unknown),
+            None => return Err(AflError::Empty("cur_input".to_string())),
         };
         unsafe {
             CURRENT_INMEMORY_EXECUTOR_PTR = self as *const InMemoryExecutor;
@@ -203,10 +203,10 @@ mod tests {
 
     impl Observer for Nopserver {
         fn reset(&mut self) -> Result<(), AflError> {
-            Err(AflError::Unknown)
+            Err(AflError::Unknown("Nop reset, testing only".to_string()))
         }
         fn post_exec(&mut self) -> Result<(), AflError> {
-            Err(AflError::Unknown)
+            Err(AflError::Unknown("Nop exec, testing only".to_string()))
         }
 
         fn as_any(&self) -> &dyn Any {

src/lib.rs

@@ -20,9 +20,13 @@ pub enum AflError {
     File(#[from] io::Error),
     #[error("Key `{0}` not in Corpus")]
     KeyNotFound(String),
-    #[error("Unknown error")]
-    Unknown,
-}
+    #[error("No items in {0}")]
+    Empty(String),
+    #[error("Not implemented: {0}")]
+    NotImplemented(String),
+    #[error("Unknown error: {0}")]
+    Unknown(String),
+   }
 
 #[cfg(test)]
 mod tests {

src/stages/mutational.rs

@@ -10,7 +10,7 @@ impl Stage for MutationalStage {
 
     fn Perform(&mut self, input: &Input, entry: &mut Entry) -> Result<(), AflError> {
         // TODO: Implement me
-        Err(AflError::Unknown);
+        Err(AflError::NotImplemented("Stage does not perform yet"));
     }
 
 }