Add last modified file (gm) (#1093)

6 files changed, 45 insertions, 6 deletions

diff --git a/book/src/keymap.md b/book/src/keymap.md
index 865a700b..59353db9 100644
--- a/book/src/keymap.md
+++ b/book/src/keymap.md
@@ -165,13 +165,14 @@ Jumps to various locations.
 | `l`   | Go to the end of the line                        | `goto_line_end`            |
 | `s`   | Go to first non-whitespace character of the line | `goto_first_nonwhitespace` |
 | `t`   | Go to the top of the screen                      | `goto_window_top`          |
-| `m`   | Go to the middle of the screen                   | `goto_window_middle`       |
+| `c`   | Go to the middle of the screen                   | `goto_window_center`       |
 | `b`   | Go to the bottom of the screen                   | `goto_window_bottom`       |
 | `d`   | Go to definition (**LSP**)                       | `goto_definition`          |
 | `y`   | Go to type definition (**LSP**)                  | `goto_type_definition`     |
 | `r`   | Go to references (**LSP**)                       | `goto_reference`           |
 | `i`   | Go to implementation (**LSP**)                   | `goto_implementation`      |
 | `a`   | Go to the last accessed/alternate file           | `goto_last_accessed_file`  |
+| `m`   | Go to the last modified/alternate file           | `goto_last_modified_file`  |
 | `n`   | Go to next buffer                                | `goto_next_buffer`         |
 | `p`   | Go to previous buffer                            | `goto_previous_buffer`     |
 | `.`   | Go to last modification in current file          | `goto_last_modification`   |
diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index 4a389429..a50b16f3 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -264,9 +264,10 @@ impl Command {
         goto_file_vsplit, "Goto files in the selection in vertical splits",
         goto_reference, "Goto references",
         goto_window_top, "Goto window top",
-        goto_window_middle, "Goto window middle",
+        goto_window_center, "Goto window center",
         goto_window_bottom, "Goto window bottom",
         goto_last_accessed_file, "Goto last accessed file",
+        goto_last_modified_file, "Goto last modified file",
         goto_last_modification, "Goto last modification",
         goto_line, "Goto line",
         goto_last_line, "Goto last line",
@@ -763,7 +764,7 @@ fn goto_window_top(cx: &mut Context) {
     goto_window(cx, Align::Top)
 }
 
-fn goto_window_middle(cx: &mut Context) {
+fn goto_window_center(cx: &mut Context) {
     goto_window(cx, Align::Center)
 }
 
@@ -3610,6 +3611,20 @@ fn goto_last_modification(cx: &mut Context) {
     }
 }
 
+fn goto_last_modified_file(cx: &mut Context) {
+    let view = view!(cx.editor);
+    let alternate_file = view
+        .last_modified_docs
+        .into_iter()
+        .flatten()
+        .find(|&id| id != view.doc);
+    if let Some(alt) = alternate_file {
+        cx.editor.switch(alt, Action::Replace);
+    } else {
+        cx.editor.set_error("no last modified buffer".to_owned())
+    }
+}
+
 fn select_mode(cx: &mut Context) {
     let (view, doc) = current!(cx.editor);
     let text = doc.text().slice(..);
diff --git a/helix-term/src/keymap.rs b/helix-term/src/keymap.rs
index 06639dcd..73cb15f8 100644
--- a/helix-term/src/keymap.rs
+++ b/helix-term/src/keymap.rs
@@ -521,9 +521,10 @@ impl Default for Keymaps {
                 "r" => goto_reference,
                 "i" => goto_implementation,
                 "t" => goto_window_top,
-                "m" => goto_window_middle,
+                "c" => goto_window_center,
                 "b" => goto_window_bottom,
                 "a" => goto_last_accessed_file,
+                "m" => goto_last_modified_file,
                 "n" => goto_next_buffer,
                 "p" => goto_previous_buffer,
                 "." => goto_last_modification,
diff --git a/helix-view/src/document.rs b/helix-view/src/document.rs
index 76b19a07..2cb33fe3 100644
--- a/helix-view/src/document.rs
+++ b/helix-view/src/document.rs
@@ -104,6 +104,7 @@ pub struct Document {
 
     last_saved_revision: usize,
     version: i32, // should be usize?
+    pub(crate) modified_since_accessed: bool,
 
     diagnostics: Vec<Diagnostic>,
     language_server: Option<Arc<helix_lsp::Client>>,
@@ -127,6 +128,7 @@ impl fmt::Debug for Document {
             // .field("history", &self.history)
             .field("last_saved_revision", &self.last_saved_revision)
             .field("version", &self.version)
+            .field("modified_since_accessed", &self.modified_since_accessed)
             .field("diagnostics", &self.diagnostics)
             // .field("language_server", &self.language_server)
             .finish()
@@ -344,6 +346,7 @@ impl Document {
             history: Cell::new(History::default()),
             savepoint: None,
             last_saved_revision: 0,
+            modified_since_accessed: false,
             language_server: None,
         }
     }
@@ -639,6 +642,9 @@ impl Document {
                     selection.clone().ensure_invariants(self.text.slice(..)),
                 );
             }
+
+            // set modified since accessed
+            self.modified_since_accessed = true;
         }
 
         if !transaction.changes().is_empty() {
diff --git a/helix-view/src/editor.rs b/helix-view/src/editor.rs
index d5913a51..9034d12c 100644
--- a/helix-view/src/editor.rs
+++ b/helix-view/src/editor.rs
@@ -369,7 +369,8 @@ impl Editor {
                         .tree
                         .traverse()
                         .any(|(_, v)| v.doc == doc.id && v.id != view.id);
-                let view = view_mut!(self);
+
+                let (view, doc) = current!(self);
                 if remove_empty_scratch {
                     // Copy `doc.id` into a variable before calling `self.documents.remove`, which requires a mutable
                     // borrow, invalidating direct access to `doc.id`.
@@ -378,7 +379,16 @@ impl Editor {
                 } else {
                     let jump = (view.doc, doc.selection(view.id).clone());
                     view.jumps.push(jump);
-                    view.last_accessed_doc = Some(view.doc);
+                    // Set last accessed doc if it is a different document
+                    if doc.id != id {
+                        view.last_accessed_doc = Some(view.doc);
+                        // Set last modified doc if modified and last modified doc is different
+                        if std::mem::take(&mut doc.modified_since_accessed)
+                            && view.last_modified_docs[0] != Some(id)
+                        {
+                            view.last_modified_docs = [Some(view.doc), view.last_modified_docs[0]];
+                        }
+                    }
                 }
 
                 let view_id = view.id;
diff --git a/helix-view/src/view.rs b/helix-view/src/view.rs
index 217a4940..94d67acd 100644
--- a/helix-view/src/view.rs
+++ b/helix-view/src/view.rs
@@ -75,6 +75,11 @@ pub struct View {
     pub jumps: JumpList,
     /// the last accessed file before the current one
     pub last_accessed_doc: Option<DocumentId>,
+    /// the last modified files before the current one
+    /// ordered from most frequent to least frequent
+    // uses two docs because we want to be able to swap between the
+    // two last modified docs which we need to manually keep track of
+    pub last_modified_docs: [Option<DocumentId>; 2],
 }
 
 impl View {
@@ -86,6 +91,7 @@ impl View {
             area: Rect::default(), // will get calculated upon inserting into tree
             jumps: JumpList::new((doc, Selection::point(0))), // TODO: use actual sel
             last_accessed_doc: None,
+            last_modified_docs: [None, None],
         }
     }