Files
oak-gpui/crates/edit_prediction_context/src/excerpt.rs
T
42583c1141 Reorganize edit prediction code and remove old experiments (#44187)
Release Notes:

- N/A

---------

Co-authored-by: Agus Zubiaga <agus@zed.dev>
Co-authored-by: Ben Kunkle <ben@zed.dev>
2025-12-04 15:56:57 -08:00

573 lines
20 KiB
Rust

use cloud_llm_client::predict_edits_v3::Line;
use language::{BufferSnapshot, LanguageId, Point, ToOffset as _, ToPoint as _};
use std::ops::Range;
use tree_sitter::{Node, TreeCursor};
use util::RangeExt;
// TODO:
//
// - Test parent signatures
//
// - Decide whether to count signatures against the excerpt size. Could instead defer this to prompt
// planning.
//
// - Still return an excerpt even if the line around the cursor doesn't fit (e.g. for a markdown
// paragraph).
//
// - Truncation of long lines.
//
// - Filter outer syntax layers that don't support edit prediction.
#[derive(Debug, Clone, PartialEq)]
pub struct EditPredictionExcerptOptions {
/// Limit for the number of bytes in the window around the cursor.
pub max_bytes: usize,
/// Minimum number of bytes in the window around the cursor. When syntax tree selection results
/// in an excerpt smaller than this, it will fall back on line-based selection.
pub min_bytes: usize,
/// Target ratio of bytes before the cursor divided by total bytes in the window.
pub target_before_cursor_over_total_bytes: f32,
}
#[derive(Debug, Clone)]
pub struct EditPredictionExcerpt {
pub range: Range<usize>,
pub line_range: Range<Line>,
pub size: usize,
}
#[derive(Debug, Clone)]
pub struct EditPredictionExcerptText {
pub body: String,
pub language_id: Option<LanguageId>,
}
impl EditPredictionExcerpt {
pub fn text(&self, buffer: &BufferSnapshot) -> EditPredictionExcerptText {
let body = buffer
.text_for_range(self.range.clone())
.collect::<String>();
let language_id = buffer.language().map(|l| l.id());
EditPredictionExcerptText { body, language_id }
}
/// Selects an excerpt around a buffer position, attempting to choose logical boundaries based
/// on TreeSitter structure and approximately targeting a goal ratio of bytesbefore vs after the
/// cursor.
///
/// When `index` is provided, the excerpt will include the signatures of parent outline items.
///
/// First tries to use AST node boundaries to select the excerpt, and falls back on line-based
/// expansion.
///
/// Returns `None` if the line around the cursor doesn't fit.
pub fn select_from_buffer(
query_point: Point,
buffer: &BufferSnapshot,
options: &EditPredictionExcerptOptions,
) -> Option<Self> {
if buffer.len() <= options.max_bytes {
log::debug!(
"using entire file for excerpt since source length ({}) <= window max bytes ({})",
buffer.len(),
options.max_bytes
);
let offset_range = 0..buffer.len();
let line_range = Line(0)..Line(buffer.max_point().row);
return Some(EditPredictionExcerpt::new(offset_range, line_range));
}
let query_offset = query_point.to_offset(buffer);
let query_line_range = query_point.row..query_point.row + 1;
let query_range = Point::new(query_line_range.start, 0).to_offset(buffer)
..Point::new(query_line_range.end, 0).to_offset(buffer);
if query_range.len() >= options.max_bytes {
return None;
}
let excerpt_selector = ExcerptSelector {
query_offset,
query_range,
query_line_range: Line(query_line_range.start)..Line(query_line_range.end),
buffer,
options,
};
if let Some(excerpt) = excerpt_selector.select_tree_sitter_nodes() {
if excerpt.size >= options.min_bytes {
return Some(excerpt);
}
log::debug!(
"tree-sitter excerpt was {} bytes, smaller than min of {}, falling back on line-based selection",
excerpt.size,
options.min_bytes
);
} else {
log::debug!(
"couldn't find excerpt via tree-sitter, falling back on line-based selection"
);
}
excerpt_selector.select_lines()
}
fn new(range: Range<usize>, line_range: Range<Line>) -> Self {
Self {
size: range.len(),
range,
line_range,
}
}
fn with_expanded_range(&self, new_range: Range<usize>, new_line_range: Range<Line>) -> Self {
if !new_range.contains_inclusive(&self.range) {
// this is an issue because parent_signature_ranges may be incorrect
log::error!("bug: with_expanded_range called with disjoint range");
}
Self::new(new_range, new_line_range)
}
fn parent_signatures_size(&self) -> usize {
self.size - self.range.len()
}
}
struct ExcerptSelector<'a> {
query_offset: usize,
query_range: Range<usize>,
query_line_range: Range<Line>,
buffer: &'a BufferSnapshot,
options: &'a EditPredictionExcerptOptions,
}
impl<'a> ExcerptSelector<'a> {
/// Finds the largest node that is smaller than the window size and contains `query_range`.
fn select_tree_sitter_nodes(&self) -> Option<EditPredictionExcerpt> {
let selected_layer_root = self.select_syntax_layer()?;
let mut cursor = selected_layer_root.walk();
loop {
let line_start = node_line_start(cursor.node());
let line_end = node_line_end(cursor.node());
let line_range = Line(line_start.row)..Line(line_end.row);
let excerpt_range =
line_start.to_offset(&self.buffer)..line_end.to_offset(&self.buffer);
if excerpt_range.contains_inclusive(&self.query_range) {
let excerpt = self.make_excerpt(excerpt_range, line_range);
if excerpt.size <= self.options.max_bytes {
return Some(self.expand_to_siblings(&mut cursor, excerpt));
}
} else {
// TODO: Should still be able to handle this case via AST nodes. For example, this
// can happen if the cursor is between two methods in a large class file.
return None;
}
if cursor
.goto_first_child_for_byte(self.query_range.start)
.is_none()
{
return None;
}
}
}
/// Select the smallest syntax layer that exceeds max_len, or the largest if none exceed max_len.
fn select_syntax_layer(&self) -> Option<Node<'_>> {
let mut smallest_exceeding_max_len: Option<Node<'_>> = None;
let mut largest: Option<Node<'_>> = None;
for layer in self
.buffer
.syntax_layers_for_range(self.query_range.start..self.query_range.start, true)
{
let layer_range = layer.node().byte_range();
if !layer_range.contains_inclusive(&self.query_range) {
continue;
}
if layer_range.len() > self.options.max_bytes {
match &smallest_exceeding_max_len {
None => smallest_exceeding_max_len = Some(layer.node()),
Some(existing) => {
if layer_range.len() < existing.byte_range().len() {
smallest_exceeding_max_len = Some(layer.node());
}
}
}
} else {
match &largest {
None => largest = Some(layer.node()),
Some(existing) if layer_range.len() > existing.byte_range().len() => {
largest = Some(layer.node())
}
_ => {}
}
}
}
smallest_exceeding_max_len.or(largest)
}
// motivation for this and `goto_previous_named_sibling` is to avoid including things like
// trailing unnamed "}" in body nodes
fn goto_next_named_sibling(cursor: &mut TreeCursor) -> bool {
while cursor.goto_next_sibling() {
if cursor.node().is_named() {
return true;
}
}
false
}
fn goto_previous_named_sibling(cursor: &mut TreeCursor) -> bool {
while cursor.goto_previous_sibling() {
if cursor.node().is_named() {
return true;
}
}
false
}
fn expand_to_siblings(
&self,
cursor: &mut TreeCursor,
mut excerpt: EditPredictionExcerpt,
) -> EditPredictionExcerpt {
let mut forward_cursor = cursor.clone();
let backward_cursor = cursor;
let mut forward_done = !Self::goto_next_named_sibling(&mut forward_cursor);
let mut backward_done = !Self::goto_previous_named_sibling(backward_cursor);
loop {
if backward_done && forward_done {
break;
}
let mut forward = None;
while !forward_done {
let new_end_point = node_line_end(forward_cursor.node());
let new_end = new_end_point.to_offset(&self.buffer);
if new_end > excerpt.range.end {
let new_excerpt = excerpt.with_expanded_range(
excerpt.range.start..new_end,
excerpt.line_range.start..Line(new_end_point.row),
);
if new_excerpt.size <= self.options.max_bytes {
forward = Some(new_excerpt);
break;
} else {
log::debug!("halting forward expansion, as it doesn't fit");
forward_done = true;
break;
}
}
forward_done = !Self::goto_next_named_sibling(&mut forward_cursor);
}
let mut backward = None;
while !backward_done {
let new_start_point = node_line_start(backward_cursor.node());
let new_start = new_start_point.to_offset(&self.buffer);
if new_start < excerpt.range.start {
let new_excerpt = excerpt.with_expanded_range(
new_start..excerpt.range.end,
Line(new_start_point.row)..excerpt.line_range.end,
);
if new_excerpt.size <= self.options.max_bytes {
backward = Some(new_excerpt);
break;
} else {
log::debug!("halting backward expansion, as it doesn't fit");
backward_done = true;
break;
}
}
backward_done = !Self::goto_previous_named_sibling(backward_cursor);
}
let go_forward = match (forward, backward) {
(Some(forward), Some(backward)) => {
let go_forward = self.is_better_excerpt(&forward, &backward);
if go_forward {
excerpt = forward;
} else {
excerpt = backward;
}
go_forward
}
(Some(forward), None) => {
log::debug!("expanding forward, since backward expansion has halted");
excerpt = forward;
true
}
(None, Some(backward)) => {
log::debug!("expanding backward, since forward expansion has halted");
excerpt = backward;
false
}
(None, None) => break,
};
if go_forward {
forward_done = !Self::goto_next_named_sibling(&mut forward_cursor);
} else {
backward_done = !Self::goto_previous_named_sibling(backward_cursor);
}
}
excerpt
}
fn select_lines(&self) -> Option<EditPredictionExcerpt> {
// early return if line containing query_offset is already too large
let excerpt = self.make_excerpt(self.query_range.clone(), self.query_line_range.clone());
if excerpt.size > self.options.max_bytes {
log::debug!(
"excerpt for cursor line is {} bytes, which exceeds the window",
excerpt.size
);
return None;
}
let signatures_size = excerpt.parent_signatures_size();
let bytes_remaining = self.options.max_bytes.saturating_sub(signatures_size);
let before_bytes =
(self.options.target_before_cursor_over_total_bytes * bytes_remaining as f32) as usize;
let start_line = {
let offset = self.query_offset.saturating_sub(before_bytes);
let point = offset.to_point(self.buffer);
Line(point.row + 1)
};
let start_offset = Point::new(start_line.0, 0).to_offset(&self.buffer);
let end_line = {
let offset = start_offset + bytes_remaining;
let point = offset.to_point(self.buffer);
Line(point.row)
};
let end_offset = Point::new(end_line.0, 0).to_offset(&self.buffer);
// this could be expanded further since recalculated `signature_size` may be smaller, but
// skipping that for now for simplicity
//
// TODO: could also consider checking if lines immediately before / after fit.
let excerpt = self.make_excerpt(start_offset..end_offset, start_line..end_line);
if excerpt.size > self.options.max_bytes {
log::error!(
"bug: line-based excerpt selection has size {}, \
which is {} bytes larger than the max size",
excerpt.size,
excerpt.size - self.options.max_bytes
);
}
return Some(excerpt);
}
fn make_excerpt(&self, range: Range<usize>, line_range: Range<Line>) -> EditPredictionExcerpt {
EditPredictionExcerpt::new(range, line_range)
}
/// Returns `true` if the `forward` excerpt is a better choice than the `backward` excerpt.
fn is_better_excerpt(
&self,
forward: &EditPredictionExcerpt,
backward: &EditPredictionExcerpt,
) -> bool {
let forward_ratio = self.excerpt_range_ratio(forward);
let backward_ratio = self.excerpt_range_ratio(backward);
let forward_delta =
(forward_ratio - self.options.target_before_cursor_over_total_bytes).abs();
let backward_delta =
(backward_ratio - self.options.target_before_cursor_over_total_bytes).abs();
let forward_is_better = forward_delta <= backward_delta;
if forward_is_better {
log::debug!(
"expanding forward since {} is closer than {} to {}",
forward_ratio,
backward_ratio,
self.options.target_before_cursor_over_total_bytes
);
} else {
log::debug!(
"expanding backward since {} is closer than {} to {}",
backward_ratio,
forward_ratio,
self.options.target_before_cursor_over_total_bytes
);
}
forward_is_better
}
/// Returns the ratio of bytes before the cursor over bytes within the range.
fn excerpt_range_ratio(&self, excerpt: &EditPredictionExcerpt) -> f32 {
let Some(bytes_before_cursor) = self.query_offset.checked_sub(excerpt.range.start) else {
log::error!("bug: edit prediction cursor offset is not outside the excerpt");
return 0.0;
};
bytes_before_cursor as f32 / excerpt.range.len() as f32
}
}
fn node_line_start(node: Node) -> Point {
Point::new(node.start_position().row as u32, 0)
}
fn node_line_end(node: Node) -> Point {
Point::new(node.end_position().row as u32 + 1, 0)
}
#[cfg(test)]
mod tests {
use super::*;
use gpui::{AppContext, TestAppContext};
use language::{Buffer, Language, LanguageConfig, LanguageMatcher, tree_sitter_rust};
use util::test::{generate_marked_text, marked_text_offsets_by};
fn create_buffer(text: &str, cx: &mut TestAppContext) -> BufferSnapshot {
let buffer = cx.new(|cx| Buffer::local(text, cx).with_language(rust_lang().into(), cx));
buffer.read_with(cx, |buffer, _| buffer.snapshot())
}
fn rust_lang() -> Language {
Language::new(
LanguageConfig {
name: "Rust".into(),
matcher: LanguageMatcher {
path_suffixes: vec!["rs".to_string()],
..Default::default()
},
..Default::default()
},
Some(tree_sitter_rust::LANGUAGE.into()),
)
.with_outline_query(include_str!("../../languages/src/rust/outline.scm"))
.unwrap()
}
fn cursor_and_excerpt_range(text: &str) -> (String, usize, Range<usize>) {
let (text, offsets) = marked_text_offsets_by(text, vec!['ˇ', '«', '»']);
(text, offsets[&'ˇ'][0], offsets[&'«'][0]..offsets[&'»'][0])
}
fn check_example(options: EditPredictionExcerptOptions, text: &str, cx: &mut TestAppContext) {
let (text, cursor, expected_excerpt) = cursor_and_excerpt_range(text);
let buffer = create_buffer(&text, cx);
let cursor_point = cursor.to_point(&buffer);
let excerpt = EditPredictionExcerpt::select_from_buffer(cursor_point, &buffer, &options)
.expect("Should select an excerpt");
pretty_assertions::assert_eq!(
generate_marked_text(&text, std::slice::from_ref(&excerpt.range), false),
generate_marked_text(&text, &[expected_excerpt], false)
);
assert!(excerpt.size <= options.max_bytes);
assert!(excerpt.range.contains(&cursor));
}
#[gpui::test]
fn test_ast_based_selection_current_node(cx: &mut TestAppContext) {
zlog::init_test();
let text = r#"
fn main() {
let x = 1;
« let ˇy = 2;
» let z = 3;
}"#;
let options = EditPredictionExcerptOptions {
max_bytes: 20,
min_bytes: 10,
target_before_cursor_over_total_bytes: 0.5,
};
check_example(options, text, cx);
}
#[gpui::test]
fn test_ast_based_selection_parent_node(cx: &mut TestAppContext) {
zlog::init_test();
let text = r#"
fn foo() {}
«fn main() {
let x = 1;
let ˇy = 2;
let z = 3;
}
»
fn bar() {}"#;
let options = EditPredictionExcerptOptions {
max_bytes: 65,
min_bytes: 10,
target_before_cursor_over_total_bytes: 0.5,
};
check_example(options, text, cx);
}
#[gpui::test]
fn test_ast_based_selection_expands_to_siblings(cx: &mut TestAppContext) {
zlog::init_test();
let text = r#"
fn main() {
« let x = 1;
let ˇy = 2;
let z = 3;
»}"#;
let options = EditPredictionExcerptOptions {
max_bytes: 50,
min_bytes: 10,
target_before_cursor_over_total_bytes: 0.5,
};
check_example(options, text, cx);
}
#[gpui::test]
fn test_line_based_selection(cx: &mut TestAppContext) {
zlog::init_test();
let text = r#"
fn main() {
let x = 1;
« if true {
let ˇy = 2;
}
let z = 3;
»}"#;
let options = EditPredictionExcerptOptions {
max_bytes: 60,
min_bytes: 45,
target_before_cursor_over_total_bytes: 0.5,
};
check_example(options, text, cx);
}
#[gpui::test]
fn test_line_based_selection_with_before_cursor_ratio(cx: &mut TestAppContext) {
zlog::init_test();
let text = r#"
fn main() {
« let a = 1;
let b = 2;
let c = 3;
let ˇd = 4;
let e = 5;
let f = 6;
»
let g = 7;
}"#;
let options = EditPredictionExcerptOptions {
max_bytes: 120,
min_bytes: 10,
target_before_cursor_over_total_bytes: 0.6,
};
check_example(options, text, cx);
}
}