text: Wrap BufferId into a newtype

crates/text/src/anchor.rs

@@ -1,6 +1,6 @@
 use crate::{
-    locator::Locator, BufferSnapshot, Point, PointUtf16, TextDimension, ToOffset, ToPoint,
-    ToPointUtf16,
+    locator::Locator, BufferId, BufferSnapshot, Point, PointUtf16, TextDimension, ToOffset,
+    ToPoint, ToPointUtf16,
 };
 use anyhow::Result;
 use std::{cmp::Ordering, fmt::Debug, ops::Range};
@@ -11,7 +11,7 @@ pub struct Anchor {
     pub timestamp: clock::Lamport,
     pub offset: usize,
     pub bias: Bias,
-    pub buffer_id: Option<u64>,
+    pub buffer_id: Option<BufferId>,
 }
 
 impl Anchor {

crates/text/src/tests.rs

@@ -18,7 +18,7 @@ fn init_logger() {
 
 #[test]
 fn test_edit() {
-    let mut buffer = Buffer::new(0, 0, "abc".into());
+    let mut buffer = Buffer::new(0, BufferId::new(1).unwrap(), "abc".into());
     assert_eq!(buffer.text(), "abc");
     buffer.edit([(3..3, "def")]);
     assert_eq!(buffer.text(), "abcdef");
@@ -42,7 +42,7 @@ fn test_random_edits(mut rng: StdRng) {
     let mut reference_string = RandomCharIter::new(&mut rng)
         .take(reference_string_len)
         .collect::<String>();
-    let mut buffer = Buffer::new(0, 0, reference_string.clone());
+    let mut buffer = Buffer::new(0, BufferId::new(1).unwrap(), reference_string.clone());
     LineEnding::normalize(&mut reference_string);
 
     buffer.set_group_interval(Duration::from_millis(rng.gen_range(0..=200)));
@@ -164,7 +164,7 @@ fn test_line_endings() {
         LineEnding::Windows
     );
 
-    let mut buffer = Buffer::new(0, 0, "one\r\ntwo\rthree".into());
+    let mut buffer = Buffer::new(0, BufferId::new(1).unwrap(), "one\r\ntwo\rthree".into());
     assert_eq!(buffer.text(), "one\ntwo\nthree");
     assert_eq!(buffer.line_ending(), LineEnding::Windows);
     buffer.check_invariants();
@@ -178,7 +178,7 @@ fn test_line_endings() {
 
 #[test]
 fn test_line_len() {
-    let mut buffer = Buffer::new(0, 0, "".into());
+    let mut buffer = Buffer::new(0, BufferId::new(1).unwrap(), "".into());
     buffer.edit([(0..0, "abcd\nefg\nhij")]);
     buffer.edit([(12..12, "kl\nmno")]);
     buffer.edit([(18..18, "\npqrs\n")]);
@@ -195,7 +195,7 @@ fn test_line_len() {
 #[test]
 fn test_common_prefix_at_position() {
     let text = "a = str; b = δα";
-    let buffer = Buffer::new(0, 0, text.into());
+    let buffer = Buffer::new(0, BufferId::new(1).unwrap(), text.into());
 
     let offset1 = offset_after(text, "str");
     let offset2 = offset_after(text, "δα");
@@ -243,7 +243,11 @@ fn test_common_prefix_at_position() {
 
 #[test]
 fn test_text_summary_for_range() {
-    let buffer = Buffer::new(0, 0, "ab\nefg\nhklm\nnopqrs\ntuvwxyz".into());
+    let buffer = Buffer::new(
+        0,
+        BufferId::new(1).unwrap(),
+        "ab\nefg\nhklm\nnopqrs\ntuvwxyz".into(),
+    );
     assert_eq!(
         buffer.text_summary_for_range::<TextSummary, _>(1..3),
         TextSummary {
@@ -313,7 +317,7 @@ fn test_text_summary_for_range() {
 
 #[test]
 fn test_chars_at() {
-    let mut buffer = Buffer::new(0, 0, "".into());
+    let mut buffer = Buffer::new(0, BufferId::new(1).unwrap(), "".into());
     buffer.edit([(0..0, "abcd\nefgh\nij")]);
     buffer.edit([(12..12, "kl\nmno")]);
     buffer.edit([(18..18, "\npqrs")]);
@@ -335,7 +339,7 @@ fn test_chars_at() {
     assert_eq!(chars.collect::<String>(), "PQrs");
 
     // Regression test:
-    let mut buffer = Buffer::new(0, 0, "".into());
+    let mut buffer = Buffer::new(0, BufferId::new(1).unwrap(), "".into());
     buffer.edit([(0..0, "[workspace]\nmembers = [\n    \"xray_core\",\n    \"xray_server\",\n    \"xray_cli\",\n    \"xray_wasm\",\n]\n")]);
     buffer.edit([(60..60, "\n")]);
 
@@ -345,7 +349,7 @@ fn test_chars_at() {
 
 #[test]
 fn test_anchors() {
-    let mut buffer = Buffer::new(0, 0, "".into());
+    let mut buffer = Buffer::new(0, BufferId::new(1).unwrap(), "".into());
     buffer.edit([(0..0, "abc")]);
     let left_anchor = buffer.anchor_before(2);
     let right_anchor = buffer.anchor_after(2);
@@ -463,7 +467,7 @@ fn test_anchors() {
 
 #[test]
 fn test_anchors_at_start_and_end() {
-    let mut buffer = Buffer::new(0, 0, "".into());
+    let mut buffer = Buffer::new(0, BufferId::new(1).unwrap(), "".into());
     let before_start_anchor = buffer.anchor_before(0);
     let after_end_anchor = buffer.anchor_after(0);
 
@@ -486,7 +490,7 @@ fn test_anchors_at_start_and_end() {
 
 #[test]
 fn test_undo_redo() {
-    let mut buffer = Buffer::new(0, 0, "1234".into());
+    let mut buffer = Buffer::new(0, BufferId::new(1).unwrap(), "1234".into());
     // Set group interval to zero so as to not group edits in the undo stack.
     buffer.set_group_interval(Duration::from_secs(0));
 
@@ -523,7 +527,7 @@ fn test_undo_redo() {
 #[test]
 fn test_history() {
     let mut now = Instant::now();
-    let mut buffer = Buffer::new(0, 0, "123456".into());
+    let mut buffer = Buffer::new(0, BufferId::new(1).unwrap(), "123456".into());
     buffer.set_group_interval(Duration::from_millis(300));
 
     let transaction_1 = buffer.start_transaction_at(now).unwrap();
@@ -590,7 +594,7 @@ fn test_history() {
 #[test]
 fn test_finalize_last_transaction() {
     let now = Instant::now();
-    let mut buffer = Buffer::new(0, 0, "123456".into());
+    let mut buffer = Buffer::new(0, BufferId::new(1).unwrap(), "123456".into());
 
     buffer.start_transaction_at(now);
     buffer.edit([(2..4, "cd")]);
@@ -625,7 +629,7 @@ fn test_finalize_last_transaction() {
 #[test]
 fn test_edited_ranges_for_transaction() {
     let now = Instant::now();
-    let mut buffer = Buffer::new(0, 0, "1234567".into());
+    let mut buffer = Buffer::new(0, BufferId::new(1).unwrap(), "1234567".into());
 
     buffer.start_transaction_at(now);
     buffer.edit([(2..4, "cd")]);
@@ -664,9 +668,9 @@ fn test_edited_ranges_for_transaction() {
 fn test_concurrent_edits() {
     let text = "abcdef";
 
-    let mut buffer1 = Buffer::new(1, 0, text.into());
-    let mut buffer2 = Buffer::new(2, 0, text.into());
-    let mut buffer3 = Buffer::new(3, 0, text.into());
+    let mut buffer1 = Buffer::new(1, BufferId::new(1).unwrap(), text.into());
+    let mut buffer2 = Buffer::new(2, BufferId::new(1).unwrap(), text.into());
+    let mut buffer3 = Buffer::new(3, BufferId::new(1).unwrap(), text.into());
 
     let buf1_op = buffer1.edit([(1..2, "12")]);
     assert_eq!(buffer1.text(), "a12cdef");
@@ -705,7 +709,7 @@ fn test_random_concurrent_edits(mut rng: StdRng) {
     let mut network = Network::new(rng.clone());
 
     for i in 0..peers {
-        let mut buffer = Buffer::new(i as ReplicaId, 0, base_text.clone());
+        let mut buffer = Buffer::new(i as ReplicaId, BufferId::new(1).unwrap(), base_text.clone());
         buffer.history.group_interval = Duration::from_millis(rng.gen_range(0..=200));
         buffers.push(buffer);
         replica_ids.push(i as u16);

crates/text/src/text.rs

@@ -26,6 +26,7 @@ pub use selection::*;
 use std::{
     borrow::Cow,
     cmp::{self, Ordering, Reverse},
+    fmt::Display,
     future::Future,
     iter::Iterator,
     ops::{self, Deref, Range, Sub},
@@ -59,10 +60,39 @@ pub struct Buffer {
     wait_for_version_txs: Vec<(clock::Global, oneshot::Sender<()>)>,
 }
 
+#[repr(transparent)]
+#[derive(Clone, Copy, Debug, Default, Hash, PartialEq, PartialOrd, Ord, Eq)]
+pub struct BufferId(u64);
+
+impl Display for BufferId {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+
+impl BufferId {
+    /// Returns Err if `id` is outside of BufferId domain.
+    pub fn new(id: u64) -> anyhow::Result<Self> {
+        Ok(Self(id))
+    }
+    /// Increments this buffer id, returning the old value.
+    /// So that's a post-increment operator in disguise.
+    pub fn next(&mut self) -> Self {
+        let old = *self;
+        self.0 += 1;
+        old
+    }
+}
+impl From<BufferId> for u64 {
+    fn from(id: BufferId) -> Self {
+        id.0
+    }
+}
+
 #[derive(Clone)]
 pub struct BufferSnapshot {
     replica_id: ReplicaId,
-    remote_id: u64,
+    remote_id: BufferId,
     visible_text: Rope,
     deleted_text: Rope,
     line_ending: LineEnding,
@@ -369,7 +399,7 @@ struct Edits<'a, D: TextDimension, F: FnMut(&FragmentSummary) -> bool> {
     old_end: D,
     new_end: D,
     range: Range<(&'a Locator, usize)>,
-    buffer_id: u64,
+    buffer_id: BufferId,
 }
 
 #[derive(Clone, Debug, Default, Eq, PartialEq)]
@@ -478,7 +508,7 @@ pub struct UndoOperation {
 }
 
 impl Buffer {
-    pub fn new(replica_id: u16, remote_id: u64, mut base_text: String) -> Buffer {
+    pub fn new(replica_id: u16, remote_id: BufferId, mut base_text: String) -> Buffer {
         let line_ending = LineEnding::detect(&base_text);
         LineEnding::normalize(&mut base_text);
 
@@ -545,7 +575,7 @@ impl Buffer {
         self.lamport_clock.replica_id
     }
 
-    pub fn remote_id(&self) -> u64 {
+    pub fn remote_id(&self) -> BufferId {
         self.remote_id
     }
 
@@ -1590,7 +1620,7 @@ impl BufferSnapshot {
         &self.visible_text
     }
 
-    pub fn remote_id(&self) -> u64 {
+    pub fn remote_id(&self) -> BufferId {
         self.remote_id
     }