Fix initial selection of Document in new view

When a new View of a Document is created, a default cursor of 0, 0 is
created, and it does not get normalized to a single width cursor until
at least one movement of the cursor happens. This appears to have no
practical negative effect that I could find, but it makes tests difficult
to work with, since the initial selection is not what you expect it to be.

This changes the initial selection of a new View to be the width of the
first grapheme in the text.

2 files changed, 11 insertions, 13 deletions

diff --git a/helix-core/src/auto_pairs.rs b/helix-core/src/auto_pairs.rs
index bcd47356..1131178e 100644
--- a/helix-core/src/auto_pairs.rs
+++ b/helix-core/src/auto_pairs.rs
@@ -1,9 +1,7 @@
 //! When typing the opening character of one of the possible pairs defined below,
 //! this module provides the functionality to insert the paired closing character.
 
-use crate::{
-    graphemes, movement::Direction, Range, Rope, RopeGraphemes, Selection, Tendril, Transaction,
-};
+use crate::{graphemes, movement::Direction, Range, Rope, Selection, Tendril, Transaction};
 use std::collections::HashMap;
 
 use log::debug;
@@ -149,14 +147,6 @@ fn prev_char(doc: &Rope, pos: usize) -> Option<char> {
     doc.get_char(pos - 1)
 }
 
-fn is_single_grapheme(doc: &Rope, range: &Range) -> bool {
-    let mut graphemes = RopeGraphemes::new(doc.slice(range.from()..range.to()));
-    let first = graphemes.next();
-    let second = graphemes.next();
-    debug!("first: {:#?}, second: {:#?}", first, second);
-    first.is_some() && second.is_none()
-}
-
 /// calculate what the resulting range should be for an auto pair insertion
 fn get_next_range(
     doc: &Rope,
@@ -189,8 +179,8 @@ fn get_next_range(
         );
     }
 
-    let single_grapheme = is_single_grapheme(doc, start_range);
     let doc_slice = doc.slice(..);
+    let single_grapheme = start_range.is_single_grapheme(doc_slice);
 
     // just skip over graphemes
     if len_inserted == 0 {
diff --git a/helix-core/src/selection.rs b/helix-core/src/selection.rs
index 1b2416f5..83bab5e3 100644
--- a/helix-core/src/selection.rs
+++ b/helix-core/src/selection.rs
@@ -8,7 +8,7 @@ use crate::{
         prev_grapheme_boundary,
     },
     movement::Direction,
-    Assoc, ChangeSet, RopeSlice,
+    Assoc, ChangeSet, RopeGraphemes, RopeSlice,
 };
 use smallvec::{smallvec, SmallVec};
 use std::borrow::Cow;
@@ -339,6 +339,14 @@ impl Range {
     pub fn cursor_line(&self, text: RopeSlice) -> usize {
         text.char_to_line(self.cursor(text))
     }
+
+    /// Returns true if this Range covers a single grapheme in the given text
+    pub fn is_single_grapheme(&self, doc: RopeSlice) -> bool {
+        let mut graphemes = RopeGraphemes::new(doc.slice(self.from()..self.to()));
+        let first = graphemes.next();
+        let second = graphemes.next();
+        first.is_some() && second.is_none()
+    }
 }
 
 impl From<(usize, usize)> for Range {