1 files changed, 102 insertions, 0 deletions
diff --git a/rust/src/implementation/passwordmaker/helperthread/message_parsing.rs b/rust/src/implementation/passwordmaker/helperthread/message_parsing.rs
new file mode 100644
index 0000000..4cda572
--- /dev/null
+++ b/rust/src/implementation/passwordmaker/helperthread/message_parsing.rs
@@ -0,0 +1,102 @@
+use std::sync::mpsc::{Receiver, RecvError};
+use super::super::thread_messages::UiToHelper;
+
+pub(super) fn receive_and_get_newest_or_important_command(receiver : &Receiver<UiToHelper>) -> Result<NewestMostImportantCommand, RecvError> {
+    let first_message = receive_and_log_error(receiver)?;
+    Ok(get_newest_or_important_command(first_message, receiver.try_iter()))
+}
+
+pub(super) struct NewestMostImportantCommand(pub UiToHelper);
+
+trait GetNewerOrMoreImportantCommand {
+    type Output;
+    fn get_newer_or_more_important_command(old: Self::Output, new: Self) -> Self::Output;
+    fn convert_first_command(self) -> Self::Output;
+}
+
+impl GetNewerOrMoreImportantCommand for UiToHelper {
+    type Output = NewestMostImportantCommand;
+
+    fn convert_first_command(self) -> Self::Output{
+        NewestMostImportantCommand(self)
+    }
+    fn get_newer_or_more_important_command(old: Self::Output, new: Self) -> Self::Output {
+        match old.0 {
+            UiToHelper::Shutdown => old,
+            UiToHelper::GeneratePassword(_) => NewestMostImportantCommand(new),
+        }
+    }
+}
+
+
+fn get_newest_or_important_command<I, It >(first_message: I, other_messages: It) -> I::Output
+    where I: GetNewerOrMoreImportantCommand,
+    It: Iterator<Item=I> 
+{
+    other_messages.fold(first_message.convert_first_command(), I::get_newer_or_more_important_command)
+}
+
+fn receive_and_log_error(receiver : &Receiver<UiToHelper>) -> Result<UiToHelper, RecvError> {
+    match receiver.recv() {
+        Ok(x) => Ok(x),
+        e => {
+                eprintln!("Connection to UI Thread closed unexpectedly.");
+                e
+             }
+    }
+}
+
+#[cfg(test)]
+mod message_parsing_tests {
+    use super::*;
+
+    #[derive(PartialEq, Debug)]
+    enum TestPrioritizedEnum {
+        Lowest(usize),
+        Highest(usize),
+        Medium(usize)
+    }
+    impl TestPrioritizedEnum{
+        fn get_prio(&self) -> usize{
+            match self {
+                TestPrioritizedEnum::Lowest(_) => 0,
+                TestPrioritizedEnum::Highest(_) => 2,
+                TestPrioritizedEnum::Medium(_) => 1,
+            }
+        }
+    }
+
+    struct TestPrioritizedEnumPrioResult(TestPrioritizedEnum);
+    impl GetNewerOrMoreImportantCommand for TestPrioritizedEnum {
+        type Output = TestPrioritizedEnumPrioResult;
+
+        fn get_newer_or_more_important_command(old: Self::Output, new: Self) -> Self::Output {
+            if old.0.get_prio() > new.get_prio() { old } else { TestPrioritizedEnumPrioResult(new) }
+        }
+
+        fn convert_first_command(self) -> Self::Output {
+            TestPrioritizedEnumPrioResult(self)
+        }
+    }
+
+    #[test]
+    fn test_get_newest_or_important_command_test(){
+        let input1 = vec![TestPrioritizedEnum::Lowest(0), TestPrioritizedEnum::Lowest(1), TestPrioritizedEnum::Lowest(2)];
+        let expected1 = TestPrioritizedEnum::Lowest(2);
+        let input2 = vec![TestPrioritizedEnum::Medium(0), TestPrioritizedEnum::Lowest(1), TestPrioritizedEnum::Lowest(2)];
+        let expected2 = TestPrioritizedEnum::Medium(0);
+        let input3 = vec![TestPrioritizedEnum::Lowest(0), TestPrioritizedEnum::Medium(1), TestPrioritizedEnum::Lowest(2)];
+        let expected3 = TestPrioritizedEnum::Medium(1);
+        let input4 = vec![TestPrioritizedEnum::Medium(0), TestPrioritizedEnum::Lowest(1), TestPrioritizedEnum::Medium(2)];
+        let expected4 = TestPrioritizedEnum::Medium(2);
+        let input5 = vec![TestPrioritizedEnum::Lowest(0), TestPrioritizedEnum::Lowest(1), TestPrioritizedEnum::Highest(2), TestPrioritizedEnum::Medium(3)];
+        let expected5 = TestPrioritizedEnum::Highest(2);
+        let data = vec![(input1, expected1), (input2, expected2), (input3, expected3), (input4, expected4), (input5, expected5)];
+        for (input, expected) in data {
+            let mut it = input.into_iter();
+            let first = it.next().unwrap();
+            let result = get_newest_or_important_command(first,it);
+            assert_eq!(result.0, expected);
+        }
+    }
+}
+\ No newline at end of file