Show file preview in split pane in fuzzy finder (#534)

* Add preview pane for fuzzy finder

* Fix picker preview lag by caching

* Add picker preview for document symbols

* Cache picker preview per document instead of view

* Use line instead of range for preview doc

* Add picker preview for buffer picker

* Fix render bug and refactor picker

* Refactor picker preview rendering

* Split picker and preview and compose

The current selected item is cloned on every event, which is
undesirable

* Refactor out clones in previewed picker

* Retrieve doc from editor if possible in filepicker

* Disable syntax highlight for picker preview

Files already loaded in memory have syntax highlighting enabled

* Ignore directory symlinks in file picker

* Cleanup unnecessary pubs and derives

* Remove unnecessary highlight from file picker

* Reorganize buffer rendering

* Use normal picker for code actions

* Remove unnecessary generics and trait impls

* Remove prepare_for_render and make render mutable

* Skip picker preview if screen small, less padding

3 files changed, 19 insertions, 6 deletions

diff --git a/helix-view/src/document.rs b/helix-view/src/document.rs
index 99faebec..8730bef2 100644
--- a/helix-view/src/document.rs
+++ b/helix-view/src/document.rs
@@ -432,14 +432,14 @@ impl Document {
     /// Create a new document from `path`. Encoding is auto-detected, but it can be manually
     /// overwritten with the `encoding` parameter.
     pub fn open(
-        path: PathBuf,
+        path: &Path,
         encoding: Option<&'static encoding_rs::Encoding>,
         theme: Option<&Theme>,
         config_loader: Option<&syntax::Loader>,
     ) -> Result<Self, Error> {
         let (rope, encoding) = if path.exists() {
             let mut file =
-                std::fs::File::open(&path).context(format!("unable to open {:?}", path))?;
+                std::fs::File::open(path).context(format!("unable to open {:?}", path))?;
             from_reader(&mut file, encoding)?
         } else {
             let encoding = encoding.unwrap_or(encoding_rs::UTF_8);
@@ -449,7 +449,7 @@ impl Document {
         let mut doc = Self::from(rope, Some(encoding));
 
         // set the path and try detecting the language
-        doc.set_path(&path)?;
+        doc.set_path(path)?;
         if let Some(loader) = config_loader {
             doc.detect_language(theme, loader);
         }
@@ -904,6 +904,10 @@ impl Document {
         &self.selections[&view_id]
     }
 
+    pub fn selections(&self) -> &HashMap<ViewId, Selection> {
+        &self.selections
+    }
+
     pub fn relative_path(&self) -> Option<PathBuf> {
         let cwdir = std::env::current_dir().expect("couldn't determine current directory");
 
diff --git a/helix-view/src/editor.rs b/helix-view/src/editor.rs
index 9b7f8429..413b7913 100644
--- a/helix-view/src/editor.rs
+++ b/helix-view/src/editor.rs
@@ -7,7 +7,11 @@ use crate::{
 };
 
 use futures_util::future;
-use std::{path::PathBuf, sync::Arc, time::Duration};
+use std::{
+    path::{Path, PathBuf},
+    sync::Arc,
+    time::Duration,
+};
 
 use slotmap::SlotMap;
 
@@ -222,7 +226,7 @@ impl Editor {
         let id = if let Some(id) = id {
             id
         } else {
-            let mut doc = Document::open(path, None, Some(&self.theme), Some(&self.syn_loader))?;
+            let mut doc = Document::open(&path, None, Some(&self.theme), Some(&self.syn_loader))?;
 
             // try to find a language server based on the language name
             let language_server = doc
@@ -316,6 +320,11 @@ impl Editor {
         self.documents.iter_mut().map(|(_id, doc)| doc)
     }
 
+    pub fn document_by_path<P: AsRef<Path>>(&self, path: P) -> Option<&Document> {
+        self.documents()
+            .find(|doc| doc.path().map(|p| p == path.as_ref()).unwrap_or(false))
+    }
+
     // pub fn current_document(&self) -> Document {
     //     let id = self.view().doc;
     //     let doc = &mut editor.documents[id];
diff --git a/helix-view/src/view.rs b/helix-view/src/view.rs
index 265f7df8..c7309fe9 100644
--- a/helix-view/src/view.rs
+++ b/helix-view/src/view.rs
@@ -10,7 +10,7 @@ use helix_core::{
 
 type Jump = (DocumentId, Selection);
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct JumpList {
     jumps: Vec<Jump>,
     current: usize,