Remove duplicates from file-based history search

src/completion/history.rs

@@ -1,8 +1,8 @@
-use std::ops::Deref;
+use std::{collections::HashSet, ops::Deref};
 
 use crate::{
-    history::SearchQuery, menu_functions::parse_selection_char, Completer, History, Span,
-    Suggestion,
+    history::SearchQuery, menu_functions::parse_selection_char, Completer, History, HistoryItem,
+    Result, Span, Suggestion,
 };
 
 const SELECTION_CHAR: char = '!';
@@ -15,33 +15,35 @@ pub(crate) struct HistoryCompleter<'menu>(&'menu dyn History);
 // updating the menu and that must happen in the same thread
 unsafe impl<'menu> Send for HistoryCompleter<'menu> {}
 
+fn search_unique(
+    completer: &HistoryCompleter,
+    line: &str,
+) -> Result<impl Iterator<Item = HistoryItem>> {
+    let parsed = parse_selection_char(line, SELECTION_CHAR);
+    let values = completer.0.search(SearchQuery::all_that_contain_rev(
+        parsed.remainder.to_string(),
+    ))?;
+
+    let mut seen_matching_command_lines = HashSet::new();
+    Ok(values
+        .into_iter()
+        .filter(move |value| seen_matching_command_lines.insert(value.command_line.clone())))
+}
+
 impl<'menu> Completer for HistoryCompleter<'menu> {
     fn complete(&mut self, line: &str, pos: usize) -> Vec<Suggestion> {
-        let parsed = parse_selection_char(line, SELECTION_CHAR);
-        let values = self
-            .0
-            .search(SearchQuery::all_that_contain_rev(
-                parsed.remainder.to_string(),
-            ))
-            .expect("todo: error handling");
-
-        values
-            .into_iter()
-            .map(|value| self.create_suggestion(line, pos, value.command_line.deref()))
-            .collect()
+        match search_unique(self, line) {
+            Err(_) => vec![],
+            Ok(search_results) => search_results
+                .map(|value| self.create_suggestion(line, pos, value.command_line.deref()))
+                .collect(),
+        }
     }
 
     // TODO: Implement `fn partial_complete()`
 
     fn total_completions(&mut self, line: &str, _pos: usize) -> usize {
-        let parsed = parse_selection_char(line, SELECTION_CHAR);
-        let count = self
-            .0
-            .count(SearchQuery::all_that_contain_rev(
-                parsed.remainder.to_string(),
-            ))
-            .expect("todo: error handling");
-        count as usize
+        search_unique(self, line).map(|i| i.count()).unwrap_or(0)
     }
 }
 
@@ -66,3 +68,91 @@ impl<'menu> HistoryCompleter<'menu> {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use rstest::rstest;
+
+    use super::*;
+    use crate::*;
+
+    fn new_history_item(command_line: &str) -> HistoryItem {
+        HistoryItem {
+            id: None,
+            start_timestamp: None,
+            command_line: command_line.to_string(),
+            session_id: None,
+            hostname: None,
+            cwd: None,
+            duration: None,
+            exit_status: None,
+            more_info: None,
+        }
+    }
+
+    #[test]
+    fn duplicates_in_history() -> Result<()> {
+        let command_line_history = vec![
+            "git stash drop",
+            "git add .",
+            "git status | something | else",
+            "git status",
+            "git commit -m 'something'",
+            "ls",
+            "git push",
+            "git status",
+        ];
+        let expected_history_size = command_line_history.len();
+        let mut history = FileBackedHistory::new(command_line_history.len())?;
+        for command_line in command_line_history {
+            history.save(new_history_item(command_line))?;
+        }
+        let input = "git s";
+        let mut sut = HistoryCompleter::new(&history);
+
+        let actual = sut.complete(input, input.len());
+        let num_completions = sut.total_completions(input, input.len());
+
+        assert_eq!(actual[0].value, "git status", "it was the last command");
+        assert_eq!(
+            actual[1].value, "git status | something | else",
+            "next match that is not 'git status' again even though it is next in history"
+        );
+        assert_eq!(actual[2].value, "git stash drop", "last match");
+        assert_eq!(actual.get(3), None);
+        assert_eq!(
+            3, num_completions,
+            "total_completions is consistent with complete"
+        );
+
+        assert_eq!(
+            history.count_all().expect("no error") as usize,
+            expected_history_size,
+            "History contains duplicates."
+        );
+        Ok(())
+    }
+
+    #[rstest]
+    #[case(vec![], "any", vec![])]
+    #[case(vec!["old match","recent match","between","recent match"], "match", vec!["recent match","old match"])]
+    #[case(vec!["a","b","c","a","b","c"], "", vec!["c","b","a"])]
+    fn complete_doesnt_return_duplicates(
+        #[case] history_items: Vec<&str>,
+        #[case] line: &str,
+        #[case] expected: Vec<&str>,
+    ) -> Result<()> {
+        let mut history = FileBackedHistory::new(history_items.len())?;
+        for history_item in history_items {
+            history.save(new_history_item(history_item))?;
+        }
+        let mut sut = HistoryCompleter::new(&history);
+        let actual: Vec<String> = sut
+            .complete(line, line.len())
+            .into_iter()
+            .map(|suggestion| suggestion.value)
+            .collect();
+        assert_eq!(actual, expected);
+        Ok(())
+    }
+}