capnprotols 0.1.3

Language server and formatter (capnpfmt) for Cap'n Proto schema files
Documentation 
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use std::sync::Arc;

use dashmap::DashMap;
use ropey::Rope;
use tower_lsp::lsp_types::{
  Position,
  Range,
  TextDocumentContentChangeEvent,
  Url,
};

#[derive(Debug, Clone)]
pub struct Document {
  pub version: i32,
  pub rope:    Rope,
  /// Whether `.capnpfmtignore` excludes this file. Computed once at open
  /// time; intentionally not refreshed on edit so the decision is stable
  /// for the lifetime of the open buffer (mirrors how most LSPs treat
  /// project-level config).
  pub ignored: bool,
}

impl Document {
  pub fn new(text: String, version: i32, ignored: bool) -> Self {
    Self {
      version,
      rope: Rope::from_str(&text),
      ignored,
    }
  }

  pub fn text(&self) -> String {
    self.rope.to_string()
  }

  /// Apply an LSP incremental change. If `range` is None, replace the whole buffer.
  pub fn apply_change(&mut self, change: TextDocumentContentChangeEvent) {
    match change.range {
      None => {
        self.rope = Rope::from_str(&change.text);
      }
      Some(range) => {
        let start = position_to_char(&self.rope, range.start);
        let end = position_to_char(&self.rope, range.end);
        self.rope.remove(start..end);
        self.rope.insert(start, &change.text);
      }
    }
  }
}

fn position_to_char(rope: &Rope, pos: Position) -> usize {
  let line = (pos.line as usize).min(rope.len_lines().saturating_sub(1));
  let line_start = rope.line_to_char(line);
  let line_slice = rope.line(line);
  // LSP uses UTF-16 code units; for ASCII schemas this matches chars. Approximate with chars
  // for now; fix to UTF-16 when we hit non-ASCII identifiers.
  let col = (pos.character as usize).min(line_slice.len_chars());
  line_start + col
}

#[allow(dead_code)]
pub fn range_to_chars(rope: &Rope, range: Range) -> std::ops::Range<usize> {
  position_to_char(rope, range.start)..position_to_char(rope, range.end)
}

#[derive(Debug, Default, Clone)]
pub struct DocumentStore {
  inner: Arc<DashMap<Url, Document>>,
}

impl DocumentStore {
  pub fn new() -> Self {
    Self::default()
  }

  pub fn open(&self, uri: Url, text: String, version: i32, ignored: bool) {
    self
      .inner
      .insert(uri, Document::new(text, version, ignored));
  }

  pub fn is_ignored(&self, uri: &Url) -> bool {
    self.inner.get(uri).map(|d| d.ignored).unwrap_or(false)
  }

  pub fn close(&self, uri: &Url) {
    self.inner.remove(uri);
  }

  pub fn update(
    &self,
    uri: &Url,
    version: i32,
    changes: Vec<TextDocumentContentChangeEvent>,
  ) -> Option<String> {
    let mut entry = self.inner.get_mut(uri)?;
    for change in changes {
      entry.apply_change(change);
    }
    entry.version = version;
    Some(entry.text())
  }

  pub fn get_text(&self, uri: &Url) -> Option<String> {
    self.inner.get(uri).map(|d| d.text())
  }
}