From 3a33fab091cb752959728a8f60bbec849775f8b8 Mon Sep 17 00:00:00 2001
From: Antonio Scandurra <me@as-cii.com>
Date: Mon, 12 Apr 2021 17:47:19 +0200
Subject: [PATCH] Generate operation when updating selection set after
 undo/redo

---
 zed/src/editor/buffer/mod.rs  | 55 +++++++++--------------------------
 zed/src/editor/buffer_view.rs | 23 ++++++++++++++-
 2 files changed, 36 insertions(+), 42 deletions(-)

diff --git a/zed/src/editor/buffer/mod.rs b/zed/src/editor/buffer/mod.rs
index c2a6eacad6..b143a4bf33 100644
--- a/zed/src/editor/buffer/mod.rs
+++ b/zed/src/editor/buffer/mod.rs
@@ -22,7 +22,7 @@ use gpui::{AppContext, Entity, ModelContext};
 use lazy_static::lazy_static;
 use rand::prelude::*;
 use std::{
-    cmp::{self, Ordering},
+    cmp,
     hash::BuildHasher,
     iter::{self, Iterator},
     ops::{AddAssign, Range},
@@ -767,10 +767,10 @@ impl Buffer {
 
     pub fn add_selection_set(
         &mut self,
-        selections: Vec<Selection>,
+        selections: impl Into<Arc<[Selection]>>,
         ctx: Option<&mut ModelContext<Self>>,
     ) -> (SelectionSetId, Operation) {
-        let selections = Arc::from(selections);
+        let selections = selections.into();
         let lamport_timestamp = self.lamport_clock.tick();
         self.selections
             .insert(lamport_timestamp, Arc::clone(&selections));
@@ -793,12 +793,11 @@ impl Buffer {
     pub fn update_selection_set(
         &mut self,
         set_id: SelectionSetId,
-        mut selections: Vec<Selection>,
+        selections: impl Into<Arc<[Selection]>>,
         ctx: Option<&mut ModelContext<Self>>,
     ) -> Result<Operation> {
-        self.merge_selections(&mut selections);
-        let selections = Arc::from(selections);
-        self.selections.insert(set_id, Arc::clone(&selections));
+        let selections = selections.into();
+        self.selections.insert(set_id, selections.clone());
 
         let lamport_timestamp = self.lamport_clock.tick();
         self.selections_last_update += 1;
@@ -843,28 +842,6 @@ impl Buffer {
             .ok_or_else(|| anyhow!("invalid selection set id {:?}", set_id))
     }
 
-    fn merge_selections(&mut self, selections: &mut Vec<Selection>) {
-        let mut i = 1;
-        while i < selections.len() {
-            if selections[i - 1]
-                .end
-                .cmp(&selections[i].start, self)
-                .unwrap()
-                >= Ordering::Equal
-            {
-                let removed = selections.remove(i);
-                if removed.start.cmp(&selections[i - 1].start, self).unwrap() < Ordering::Equal {
-                    selections[i - 1].start = removed.start;
-                }
-                if removed.end.cmp(&selections[i - 1].end, self).unwrap() > Ordering::Equal {
-                    selections[i - 1].end = removed.end;
-                }
-            } else {
-                i += 1;
-            }
-        }
-    }
-
     pub fn apply_ops<I: IntoIterator<Item = Operation>>(
         &mut self,
         ops: I,
@@ -1063,21 +1040,19 @@ impl Buffer {
         Ok(())
     }
 
-    pub fn undo(&mut self, ctx: Option<&mut ModelContext<Self>>) -> Vec<Operation> {
+    pub fn undo(&mut self, mut ctx: Option<&mut ModelContext<Self>>) -> Vec<Operation> {
         let was_dirty = self.is_dirty();
         let old_version = self.version.clone();
 
         let mut ops = Vec::new();
         if let Some(transaction) = self.history.pop_undo() {
-            let transaction_selections = transaction.selections_before.clone();
+            let selections = transaction.selections_before.clone();
             for edit_id in transaction.edits.clone() {
                 ops.push(self.undo_or_redo(edit_id).unwrap());
             }
 
-            if let Some((set_id, transaction_selections)) = transaction_selections {
-                if let Some(selections) = self.selections.get_mut(&set_id) {
-                    *selections = transaction_selections;
-                }
+            if let Some((set_id, selections)) = selections {
+                let _ = self.update_selection_set(set_id, selections, ctx.as_deref_mut());
             }
         }
 
@@ -1092,21 +1067,19 @@ impl Buffer {
         ops
     }
 
-    pub fn redo(&mut self, ctx: Option<&mut ModelContext<Self>>) -> Vec<Operation> {
+    pub fn redo(&mut self, mut ctx: Option<&mut ModelContext<Self>>) -> Vec<Operation> {
         let was_dirty = self.is_dirty();
         let old_version = self.version.clone();
 
         let mut ops = Vec::new();
         if let Some(transaction) = self.history.pop_redo() {
-            let transaction_selections = transaction.selections_after.clone();
+            let selections = transaction.selections_after.clone();
             for edit_id in transaction.edits.clone() {
                 ops.push(self.undo_or_redo(edit_id).unwrap());
             }
 
-            if let Some((set_id, transaction_selections)) = transaction_selections {
-                if let Some(selections) = self.selections.get_mut(&set_id) {
-                    *selections = transaction_selections;
-                }
+            if let Some((set_id, selections)) = selections {
+                let _ = self.update_selection_set(set_id, selections, ctx.as_deref_mut());
             }
         }
 
diff --git a/zed/src/editor/buffer_view.rs b/zed/src/editor/buffer_view.rs
index a4d6f15b2c..22cd3f0c9f 100644
--- a/zed/src/editor/buffer_view.rs
+++ b/zed/src/editor/buffer_view.rs
@@ -721,7 +721,28 @@ impl BufferView {
             .unwrap()
     }
 
-    fn update_selections(&self, selections: Vec<Selection>, ctx: &mut ViewContext<Self>) {
+    fn update_selections(&self, mut selections: Vec<Selection>, ctx: &mut ViewContext<Self>) {
+        let buffer = self.buffer.as_ref(ctx);
+        let mut i = 1;
+        while i < selections.len() {
+            if selections[i - 1]
+                .end
+                .cmp(&selections[i].start, buffer)
+                .unwrap()
+                >= Ordering::Equal
+            {
+                let removed = selections.remove(i);
+                if removed.start.cmp(&selections[i - 1].start, buffer).unwrap() < Ordering::Equal {
+                    selections[i - 1].start = removed.start;
+                }
+                if removed.end.cmp(&selections[i - 1].end, buffer).unwrap() > Ordering::Equal {
+                    selections[i - 1].end = removed.end;
+                }
+            } else {
+                i += 1;
+            }
+        }
+
         let op = self.buffer.update(ctx, |buffer, ctx| {
             buffer
                 .update_selection_set(self.selection_set_id, selections, Some(ctx))