WIP: Save splits on quit and automatically load it at startup.

With this patch, Helix will automatically save the splits before
quitting and then load it when starting.

TODO: Unit testing?

book/src/editor.md

@@ -475,6 +475,7 @@ The state is formatted with bincode, and stored in files in the state directory
 | `commands` | whether to persist command history between sessions | `false` |
 | `search` | whether to persist search history between sessions | `false` |
 | `clipboard` | whether to persist helix's internal clipboard between sessions | `false` |
+| `autostart-splits` | Set to `true` to automatically save the last split before quitting and load it when starting. | `false` |
 | `old-files-exclusions` | a list of regexes defining file paths to exclude from persistence | `[".*/\.git/.*", ".*/COMMIT_EDITMSG"]` |
 | `old-files-trim` | number of old-files entries to keep when helix trims the state files at startup | `100` |
 | `commands-trim` | number of command history entries to keep when helix trims the state files at startup | `100` |

helix-term/src/application.rs

@@ -248,6 +248,11 @@ impl Application {
             }
         } else if stdin().is_tty() || cfg!(feature = "integration") {
             editor.new_file(Action::VerticalSplit);
+            if persistence_config.autostart_splits {
+                if editor.load_split("".to_string()).is_err() {
+                    editor.set_error("Unable to load default split. First time using it?");
+                }
+            }
         } else {
             editor
                 .new_file_from_stdin(Action::VerticalSplit)

helix-term/src/commands/typed.rs

@@ -797,7 +797,9 @@ fn quit_all_impl(cx: &mut compositor::Context, force: bool) -> anyhow::Result<()
     }
 
     // save split in default before quitting
-    cx.editor.save_split("".to_string());
+    if cx.editor.config().persistence.autostart_splits {
+        cx.editor.save_split("".to_string());
+    }
 
     // close all views
     let views: Vec<_> = cx.editor.tree.views().map(|(view, _)| view.id).collect();

helix-view/src/editor.rs

@@ -973,6 +973,7 @@ pub struct PersistenceConfig {
     pub commands: bool,
     pub search: bool,
     pub clipboard: bool,
+    pub autostart_splits: bool,
     pub old_files_exclusions: Vec<EqRegex>,
     pub old_files_trim: usize,
     pub commands_trim: usize,
@@ -988,6 +989,7 @@ impl Default for PersistenceConfig {
             commands: false,
             search: false,
             clipboard: false,
+            autostart_splits: false,
             // TODO: any more defaults we should add here?
             old_files_exclusions: [r".*/\.git/.*", r".*/COMMIT_EDITMSG"]
                 .iter()