helix-term: implement buffer completer

In order to implement this completer, the completion function needs to
be able to access the compositor's context (to allow it to get the
list of buffers currently open in the context's editor).

1 files changed, 41 insertions, 6 deletions

diff --git a/helix-term/src/ui/mod.rs b/helix-term/src/ui/mod.rs
index 7f6d9f7c..263342b7 100644
--- a/helix-term/src/ui/mod.rs
+++ b/helix-term/src/ui/mod.rs
@@ -30,7 +30,7 @@ pub fn regex_prompt(
     cx: &mut crate::commands::Context,
     prompt: std::borrow::Cow<'static, str>,
     history_register: Option<char>,
-    completion_fn: impl FnMut(&str) -> Vec<prompt::Completion> + 'static,
+    completion_fn: impl FnMut(&crate::compositor::Context, &str) -> Vec<prompt::Completion> + 'static,
     fun: impl Fn(&mut View, &mut Document, Regex, PromptEvent) + 'static,
 ) -> Prompt {
     let (view, doc) = current!(cx.editor);
@@ -168,18 +168,53 @@ pub fn file_picker(root: PathBuf, config: &helix_view::editor::Config) -> FilePi
 }
 
 pub mod completers {
+    use crate::compositor::Context;
     use crate::ui::prompt::Completion;
     use fuzzy_matcher::skim::SkimMatcherV2 as Matcher;
     use fuzzy_matcher::FuzzyMatcher;
+    use helix_view::document::SCRATCH_BUFFER_NAME;
     use helix_view::editor::Config;
     use helix_view::theme;
     use once_cell::sync::Lazy;
     use std::borrow::Cow;
     use std::cmp::Reverse;
 
-    pub type Completer = fn(&str) -> Vec<Completion>;
+    pub type Completer = fn(&Context, &str) -> Vec<Completion>;
 
-    pub fn theme(input: &str) -> Vec<Completion> {
+    pub fn none(_cx: &Context, _input: &str) -> Vec<Completion> {
+        Vec::new()
+    }
+
+    pub fn buffer(cx: &Context, input: &str) -> Vec<Completion> {
+        let mut names: Vec<_> = cx
+            .editor
+            .documents
+            .iter()
+            .map(|(_id, doc)| {
+                let name = doc
+                    .relative_path()
+                    .map(|p| p.display().to_string())
+                    .unwrap_or_else(|| String::from(SCRATCH_BUFFER_NAME));
+                ((0..), Cow::from(name))
+            })
+            .collect();
+
+        let matcher = Matcher::default();
+
+        let mut matches: Vec<_> = names
+            .into_iter()
+            .filter_map(|(_range, name)| {
+                matcher.fuzzy_match(&name, input).map(|score| (name, score))
+            })
+            .collect();
+
+        matches.sort_unstable_by_key(|(_file, score)| Reverse(*score));
+        names = matches.into_iter().map(|(name, _)| ((0..), name)).collect();
+
+        names
+    }
+
+    pub fn theme(_cx: &Context, input: &str) -> Vec<Completion> {
         let mut names = theme::Loader::read_names(&helix_core::runtime_dir().join("themes"));
         names.extend(theme::Loader::read_names(
             &helix_core::config_dir().join("themes"),
@@ -207,7 +242,7 @@ pub mod completers {
         names
     }
 
-    pub fn setting(input: &str) -> Vec<Completion> {
+    pub fn setting(_cx: &Context, input: &str) -> Vec<Completion> {
         static KEYS: Lazy<Vec<String>> = Lazy::new(|| {
             serde_json::to_value(Config::default())
                 .unwrap()
@@ -232,7 +267,7 @@ pub mod completers {
             .collect()
     }
 
-    pub fn filename(input: &str) -> Vec<Completion> {
+    pub fn filename(_cx: &Context, input: &str) -> Vec<Completion> {
         filename_impl(input, |entry| {
             let is_dir = entry.file_type().map_or(false, |entry| entry.is_dir());
 
@@ -244,7 +279,7 @@ pub mod completers {
         })
     }
 
-    pub fn directory(input: &str) -> Vec<Completion> {
+    pub fn directory(_cx: &Context, input: &str) -> Vec<Completion> {
         filename_impl(input, |entry| {
             let is_dir = entry.file_type().map_or(false, |entry| entry.is_dir());