Extract multi_buffer module out of editor (#3170)

Release Notes:

- N/A

crates/multi_buffer/Cargo.toml

@@ -0,0 +1,80 @@
+[package]
+name = "multi_buffer"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[lib]
+path = "src/multi_buffer.rs"
+doctest = false
+
+[features]
+test-support = [
+    "copilot/test-support",
+    "text/test-support",
+    "language/test-support",
+    "gpui/test-support",
+    "util/test-support",
+    "tree-sitter-rust",
+    "tree-sitter-typescript"
+]
+
+[dependencies]
+client = { path = "../client" }
+clock = { path = "../clock" }
+collections = { path = "../collections" }
+context_menu = { path = "../context_menu" }
+git = { path = "../git" }
+gpui = { path = "../gpui" }
+language = { path = "../language" }
+lsp = { path = "../lsp" }
+rich_text = { path = "../rich_text" }
+settings = { path = "../settings" }
+snippet = { path = "../snippet" }
+sum_tree = { path = "../sum_tree" }
+text = { path = "../text" }
+theme = { path = "../theme" }
+util = { path = "../util" }
+
+aho-corasick = "1.1"
+anyhow.workspace = true
+convert_case = "0.6.0"
+futures.workspace = true
+indoc = "1.0.4"
+itertools = "0.10"
+lazy_static.workspace = true
+log.workspace = true
+ordered-float.workspace = true
+parking_lot.workspace = true
+postage.workspace = true
+pulldown-cmark = { version = "0.9.2", default-features = false }
+rand.workspace = true
+schemars.workspace = true
+serde.workspace = true
+serde_derive.workspace = true
+smallvec.workspace = true
+smol.workspace = true
+
+tree-sitter-rust = { workspace = true, optional = true }
+tree-sitter-html = { workspace = true, optional = true }
+tree-sitter-typescript = { workspace = true, optional = true }
+
+[dev-dependencies]
+copilot = { path = "../copilot", features = ["test-support"] }
+text = { path = "../text", features = ["test-support"] }
+language = { path = "../language", features = ["test-support"] }
+lsp = { path = "../lsp", features = ["test-support"] }
+gpui = { path = "../gpui", features = ["test-support"] }
+util = { path = "../util", features = ["test-support"] }
+project = { path = "../project", features = ["test-support"] }
+settings = { path = "../settings", features = ["test-support"] }
+workspace = { path = "../workspace", features = ["test-support"] }
+
+ctor.workspace = true
+env_logger.workspace = true
+rand.workspace = true
+unindent.workspace = true
+tree-sitter.workspace = true
+tree-sitter-rust.workspace = true
+tree-sitter-html.workspace = true
+tree-sitter-typescript.workspace = true

crates/multi_buffer/src/anchor.rs

@@ -0,0 +1,138 @@
+use super::{ExcerptId, MultiBufferSnapshot, ToOffset, ToOffsetUtf16, ToPoint};
+use language::{OffsetUtf16, Point, TextDimension};
+use std::{
+    cmp::Ordering,
+    ops::{Range, Sub},
+};
+use sum_tree::Bias;
+
+#[derive(Clone, Copy, Eq, PartialEq, Debug, Hash)]
+pub struct Anchor {
+    pub buffer_id: Option<u64>,
+    pub excerpt_id: ExcerptId,
+    pub text_anchor: text::Anchor,
+}
+
+impl Anchor {
+    pub fn min() -> Self {
+        Self {
+            buffer_id: None,
+            excerpt_id: ExcerptId::min(),
+            text_anchor: text::Anchor::MIN,
+        }
+    }
+
+    pub fn max() -> Self {
+        Self {
+            buffer_id: None,
+            excerpt_id: ExcerptId::max(),
+            text_anchor: text::Anchor::MAX,
+        }
+    }
+
+    pub fn cmp(&self, other: &Anchor, snapshot: &MultiBufferSnapshot) -> Ordering {
+        let excerpt_id_cmp = self.excerpt_id.cmp(&other.excerpt_id, snapshot);
+        if excerpt_id_cmp.is_eq() {
+            if self.excerpt_id == ExcerptId::min() || self.excerpt_id == ExcerptId::max() {
+                Ordering::Equal
+            } else if let Some(excerpt) = snapshot.excerpt(self.excerpt_id) {
+                self.text_anchor.cmp(&other.text_anchor, &excerpt.buffer)
+            } else {
+                Ordering::Equal
+            }
+        } else {
+            excerpt_id_cmp
+        }
+    }
+
+    pub fn bias(&self) -> Bias {
+        self.text_anchor.bias
+    }
+
+    pub fn bias_left(&self, snapshot: &MultiBufferSnapshot) -> Anchor {
+        if self.text_anchor.bias != Bias::Left {
+            if let Some(excerpt) = snapshot.excerpt(self.excerpt_id) {
+                return Self {
+                    buffer_id: self.buffer_id,
+                    excerpt_id: self.excerpt_id.clone(),
+                    text_anchor: self.text_anchor.bias_left(&excerpt.buffer),
+                };
+            }
+        }
+        self.clone()
+    }
+
+    pub fn bias_right(&self, snapshot: &MultiBufferSnapshot) -> Anchor {
+        if self.text_anchor.bias != Bias::Right {
+            if let Some(excerpt) = snapshot.excerpt(self.excerpt_id) {
+                return Self {
+                    buffer_id: self.buffer_id,
+                    excerpt_id: self.excerpt_id.clone(),
+                    text_anchor: self.text_anchor.bias_right(&excerpt.buffer),
+                };
+            }
+        }
+        self.clone()
+    }
+
+    pub fn summary<D>(&self, snapshot: &MultiBufferSnapshot) -> D
+    where
+        D: TextDimension + Ord + Sub<D, Output = D>,
+    {
+        snapshot.summary_for_anchor(self)
+    }
+
+    pub fn is_valid(&self, snapshot: &MultiBufferSnapshot) -> bool {
+        if *self == Anchor::min() || *self == Anchor::max() {
+            true
+        } else if let Some(excerpt) = snapshot.excerpt(self.excerpt_id) {
+            excerpt.contains(self)
+                && (self.text_anchor == excerpt.range.context.start
+                    || self.text_anchor == excerpt.range.context.end
+                    || self.text_anchor.is_valid(&excerpt.buffer))
+        } else {
+            false
+        }
+    }
+}
+
+impl ToOffset for Anchor {
+    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize {
+        self.summary(snapshot)
+    }
+}
+
+impl ToOffsetUtf16 for Anchor {
+    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
+        self.summary(snapshot)
+    }
+}
+
+impl ToPoint for Anchor {
+    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
+        self.summary(snapshot)
+    }
+}
+
+pub trait AnchorRangeExt {
+    fn cmp(&self, b: &Range<Anchor>, buffer: &MultiBufferSnapshot) -> Ordering;
+    fn to_offset(&self, content: &MultiBufferSnapshot) -> Range<usize>;
+    fn to_point(&self, content: &MultiBufferSnapshot) -> Range<Point>;
+}
+
+impl AnchorRangeExt for Range<Anchor> {
+    fn cmp(&self, other: &Range<Anchor>, buffer: &MultiBufferSnapshot) -> Ordering {
+        match self.start.cmp(&other.start, buffer) {
+            Ordering::Equal => other.end.cmp(&self.end, buffer),
+            ord => ord,
+        }
+    }
+
+    fn to_offset(&self, content: &MultiBufferSnapshot) -> Range<usize> {
+        self.start.to_offset(content)..self.end.to_offset(content)
+    }
+
+    fn to_point(&self, content: &MultiBufferSnapshot) -> Range<Point> {
+        self.start.to_point(content)..self.end.to_point(content)
+    }
+}