rune: Make SourceLine and similar APIs public

udoprog · udoprog · commit ab1878a50e74 · 2025-06-07T17:02:49.000+02:00
diff --git a/crates/rune-wasm/src/lib.rs b/crates/rune-wasm/src/lib.rs
@@ -201,11 +201,10 @@ async fn inner_compile(
                             let span = error.span();
 
                             let start = WasmPosition::from(
-                                source.pos_to_utf8_linecol(span.start.into_usize()),
-                            );
-                            let end = WasmPosition::from(
-                                source.pos_to_utf8_linecol(span.end.into_usize()),
+                                source.find_line_column(span.start.into_usize()),
                             );
+                            let end =
+                                WasmPosition::from(source.find_line_column(span.end.into_usize()));
 
                             diagnostics.push(WasmDiagnostic {
                                 kind: WasmDiagnosticKind::Error,
@@ -218,10 +217,10 @@ async fn inner_compile(
                             LinkerError::MissingFunction { hash, spans } => {
                                 for (span, _) in spans {
                                     let start = WasmPosition::from(
-                                        source.pos_to_utf8_linecol(span.start.into_usize()),
+                                        source.find_line_column(span.start.into_usize()),
                                     );
                                     let end = WasmPosition::from(
-                                        source.pos_to_utf8_linecol(span.end.into_usize()),
+                                        source.find_line_column(span.end.into_usize()),
                                     );
 
                                     diagnostics.push(WasmDiagnostic {
@@ -243,8 +242,8 @@ async fn inner_compile(
 
                 if let Some(source) = sources.get(warning.source_id()) {
                     let start =
-                        WasmPosition::from(source.pos_to_utf8_linecol(span.start.into_usize()));
-                    let end = WasmPosition::from(source.pos_to_utf8_linecol(span.end.into_usize()));
+                        WasmPosition::from(source.find_line_column(span.start.into_usize()));
+                    let end = WasmPosition::from(source.find_line_column(span.end.into_usize()));
 
                     diagnostics.push(WasmDiagnostic {
                         kind: WasmDiagnosticKind::Warning,
@@ -323,12 +322,11 @@ async fn inner_compile(
                 if let Some(inst) = debug.instruction_at(ip) {
                     if let Some(source) = sources.get(inst.source_id) {
                         let start = WasmPosition::from(
-                            source.pos_to_utf8_linecol(inst.span.start.into_usize()),
+                            source.find_line_column(inst.span.start.into_usize()),
                         );
 
-                        let end = WasmPosition::from(
-                            source.pos_to_utf8_linecol(inst.span.end.into_usize()),
-                        );
+                        let end =
+                            WasmPosition::from(source.find_line_column(inst.span.end.into_usize()));
 
                         diagnostics.push(WasmDiagnostic {
                             kind: WasmDiagnosticKind::Error,
diff --git a/crates/rune/src/diagnostics/emit.rs b/crates/rune/src/diagnostics/emit.rs
@@ -22,7 +22,7 @@ use crate::hash::Hash;
 use crate::runtime::DebugInfo;
 use crate::runtime::{DebugInst, Protocol, Unit, VmError, VmErrorAt, VmErrorKind};
 use crate::Context;
-use crate::{Diagnostics, Source, SourceId, Sources};
+use crate::{Diagnostics, SourceId, Sources};
 
 struct StackFrame {
     source_id: SourceId,
@@ -419,108 +419,6 @@ impl Unit {
     }
 }
 
-impl Source {
-    /// Print formatted diagnostics about a source conveniently.
-    pub fn source_line(&self, span: Span) -> Option<SourceLine<'_>> {
-        let (count, column, line, span) = line_for(self, span)?;
-
-        Some(SourceLine {
-            name: self.name(),
-            count,
-            column,
-            line,
-            span,
-        })
-    }
-}
-
-/// An extracted source line.
-pub struct SourceLine<'a> {
-    name: &'a str,
-    count: usize,
-    column: usize,
-    line: &'a str,
-    span: Span,
-}
-
-impl SourceLine<'_> {
-    /// Write a source line to the given output.
-    pub fn write(&self, o: &mut dyn WriteColor) -> io::Result<()> {
-        let mut highlight = termcolor::ColorSpec::new();
-        highlight.set_fg(Some(termcolor::Color::Yellow));
-
-        let mut new_line = termcolor::ColorSpec::new();
-        new_line.set_fg(Some(termcolor::Color::Red));
-
-        let line = self.line.trim_end();
-        let end = self.span.end.into_usize().min(line.len());
-
-        let before = &line[0..self.span.start.into_usize()].trim_start();
-        let inner = &line[self.span.start.into_usize()..end];
-        let after = &line[end..];
-
-        {
-            let name = self.name;
-            let column = self.count + 1;
-            let start = self.column + 1;
-            let end = start + inner.chars().count();
-            write!(o, "{name}:{column}:{start}-{end}: ")?;
-        }
-
-        write!(o, "{before}")?;
-        o.set_color(&highlight)?;
-        write!(o, "{inner}")?;
-        o.reset()?;
-        write!(o, "{after}")?;
-
-        if self.span.end != end {
-            o.set_color(&new_line)?;
-            write!(o, "\\n")?;
-            o.reset()?;
-        }
-
-        Ok(())
-    }
-}
-
-/// Get the line number and source line for the given source and span.
-pub fn line_for(source: &Source, span: Span) -> Option<(usize, usize, &str, Span)> {
-    let line_starts = source.line_starts();
-
-    let line = match line_starts.binary_search(&span.start.into_usize()) {
-        Ok(n) => n,
-        Err(n) => n.saturating_sub(1),
-    };
-
-    let start = *line_starts.get(line)?;
-    let end = line.checked_add(1)?;
-
-    let s = if let Some(end) = line_starts.get(end) {
-        source.get(start..*end)?
-    } else {
-        source.get(start..)?
-    };
-
-    let line_end = span.start.into_usize().saturating_sub(start);
-    let column = s
-        .get(..line_end)
-        .into_iter()
-        .flat_map(|s| s.chars())
-        .count();
-
-    let start = start.try_into().unwrap();
-
-    Some((
-        line,
-        column,
-        s,
-        Span::new(
-            span.start.saturating_sub(start),
-            span.end.saturating_sub(start),
-        ),
-    ))
-}
-
 /// Helper to emit diagnostics for a warning.
 fn warning_diagnostics_emit<O>(
     this: &WarningDiagnostic,
diff --git a/crates/rune/src/indexing/indexer.rs b/crates/rune/src/indexing/indexer.rs
@@ -384,7 +384,7 @@ impl Indexer<'_, '_> {
             .q
             .sources
             .get(self.source_id)
-            .map(|s| s.pos_to_utf8_linecol(ast.open.span.start.into_usize()))
+            .map(|s| s.find_line_column(ast.open.span.start.into_usize()))
             .unwrap_or_default();
 
         // 1-indexed as that is what most editors will use
diff --git a/crates/rune/src/languageserver/state.rs b/crates/rune/src/languageserver/state.rs
@@ -123,8 +123,8 @@ impl StateEncoding {
     /// Get line column out of source.
     pub(super) fn source_position(&self, source: &Source, at: usize) -> Result<lsp::Position> {
         let (l, c) = match self {
-            StateEncoding::Utf16 => source.pos_to_utf16cu_linecol(at),
-            StateEncoding::Utf8 => source.pos_to_utf8_linecol(at),
+            StateEncoding::Utf16 => source.find_utf16cu_line_column(at),
+            StateEncoding::Utf8 => source.find_line_column(at),
         };
 
         Ok(lsp::Position {
diff --git a/crates/rune/src/source.rs b/crates/rune/src/source.rs
@@ -15,15 +15,18 @@ use core::iter;
 use core::ops::Range;
 use core::slice;
 
+#[cfg(feature = "emit")]
+use std::io;
+
 use crate as rune;
 #[cfg(feature = "std")]
 use crate::alloc::borrow::Cow;
 use crate::alloc::path::Path;
 use crate::alloc::prelude::*;
 use crate::alloc::{self, Box};
-
-#[cfg(feature = "emit")]
 use crate::ast::Span;
+#[cfg(feature = "emit")]
+use crate::termcolor::{self, WriteColor};
 
 /// Error raised when constructing a source.
 #[derive(Debug)]
@@ -176,7 +179,6 @@ impl Source {
     }
 
     /// Access all line starts in the source.
-    #[cfg(feature = "emit")]
     pub(crate) fn line_starts(&self) -> &[usize] {
         &self.line_starts
     }
@@ -219,10 +221,27 @@ impl Source {
         self.path.as_deref()
     }
 
-    /// Convert the given offset to a utf-16 line and character.
-    #[cfg(feature = "languageserver")]
-    pub(crate) fn pos_to_utf16cu_linecol(&self, offset: usize) -> (usize, usize) {
-        let (line, offset, rest) = self.position(offset);
+    /// Convert the given position to a utf-8 line position in code units.
+    ///
+    /// A position is a character offset into the source in utf-8 characters.
+    ///
+    /// Note that utf-8 code units is what you'd count when using the
+    /// [`str::chars()`] iterator.
+    pub fn find_line_column(&self, position: usize) -> (usize, usize) {
+        let (line, offset, rest) = self.position(position);
+        let col = rest.char_indices().take_while(|&(n, _)| n < offset).count();
+        (line, col)
+    }
+
+    /// Convert the given position to a utf-16 code units line and character.
+    ///
+    /// A position is a character offset into the source in utf-16 characters.
+    ///
+    /// Note that utf-16 code units is what you'd count when iterating over the
+    /// string in terms of characters as-if they would have been encoded with
+    /// [`char::encode_utf16()`].
+    pub fn find_utf16cu_line_column(&self, position: usize) -> (usize, usize) {
+        let (line, offset, rest) = self.position(position);
 
         let col = rest
             .char_indices()
@@ -232,11 +251,19 @@ impl Source {
         (line, col)
     }
 
-    /// Convert the given offset to a utf-16 line and character.
-    pub fn pos_to_utf8_linecol(&self, offset: usize) -> (usize, usize) {
-        let (line, offset, rest) = self.position(offset);
-        let col = rest.char_indices().take_while(|&(n, _)| n < offset).count();
-        (line, col)
+    /// Fetch [`SourceLine`] information for the given span.
+    pub fn source_line(&self, span: Span) -> Option<SourceLine<'_>> {
+        let (line, column, text, _span) = line_for(self, span)?;
+
+        Some(SourceLine {
+            #[cfg(feature = "emit")]
+            name: self.name(),
+            line,
+            column,
+            text,
+            #[cfg(feature = "emit")]
+            span: _span,
+        })
     }
 
     /// Get the line index for the given byte.
@@ -265,7 +292,7 @@ impl Source {
     #[cfg(feature = "emit")]
     pub(crate) fn line(&self, span: Span) -> Option<(usize, usize, [&str; 3])> {
         let from = span.range();
-        let (lin, col) = self.pos_to_utf8_linecol(from.start);
+        let (lin, col) = self.find_line_column(from.start);
         let line = self.line_range(lin)?;
 
         let start = from.start.checked_sub(line.start)?;
@@ -320,6 +347,61 @@ impl fmt::Debug for Source {
     }
 }
 
+/// An extracted source line.
+pub struct SourceLine<'a> {
+    #[cfg(feature = "emit")]
+    name: &'a str,
+    /// The line number in the source.
+    pub line: usize,
+    /// The column number in the source.
+    pub column: usize,
+    /// The text of the span.
+    pub text: &'a str,
+    #[cfg(feature = "emit")]
+    span: Span,
+}
+
+impl SourceLine<'_> {
+    /// Pretty write a source line to the given output.
+    #[cfg(feature = "emit")]
+    pub(crate) fn write(&self, o: &mut dyn WriteColor) -> io::Result<()> {
+        let mut highlight = termcolor::ColorSpec::new();
+        highlight.set_fg(Some(termcolor::Color::Yellow));
+
+        let mut new_line = termcolor::ColorSpec::new();
+        new_line.set_fg(Some(termcolor::Color::Red));
+
+        let text = self.text.trim_end();
+        let end = self.span.end.into_usize().min(text.len());
+
+        let before = &text[0..self.span.start.into_usize()].trim_start();
+        let inner = &text[self.span.start.into_usize()..end];
+        let after = &text[end..];
+
+        {
+            let name = self.name;
+            let line = self.line + 1;
+            let start = self.column + 1;
+            let end = start + inner.chars().count();
+            write!(o, "{name}:{line}:{start}-{end}: ")?;
+        }
+
+        write!(o, "{before}")?;
+        o.set_color(&highlight)?;
+        write!(o, "{inner}")?;
+        o.reset()?;
+        write!(o, "{after}")?;
+
+        if self.span.end != end {
+            o.set_color(&new_line)?;
+            write!(o, "\\n")?;
+            o.reset()?;
+        }
+
+        Ok(())
+    }
+}
+
 /// Holder for the name of a source.
 #[derive(Default, Debug, TryClone, PartialEq, Eq)]
 enum SourceName {
@@ -331,6 +413,46 @@ enum SourceName {
     Name(Box<str>),
 }
 
+#[inline(always)]
 fn line_starts(source: &str) -> impl Iterator<Item = usize> + '_ {
     iter::once(0).chain(source.match_indices('\n').map(|(i, _)| i + 1))
 }
+
+/// Get the line number and source line for the given source and span.
+fn line_for(source: &Source, span: Span) -> Option<(usize, usize, &str, Span)> {
+    let line_starts = source.line_starts();
+
+    let line = match line_starts.binary_search(&span.start.into_usize()) {
+        Ok(n) => n,
+        Err(n) => n.saturating_sub(1),
+    };
+
+    let start = *line_starts.get(line)?;
+    let end = line.checked_add(1)?;
+
+    let s = if let Some(end) = line_starts.get(end) {
+        source.get(start..*end)?
+    } else {
+        source.get(start..)?
+    };
+
+    let line_end = span.start.into_usize().saturating_sub(start);
+
+    let column = s
+        .get(..line_end)
+        .into_iter()
+        .flat_map(|s| s.chars())
+        .count();
+
+    let start = start.try_into().unwrap();
+
+    Some((
+        line,
+        column,
+        s,
+        Span::new(
+            span.start.saturating_sub(start),
+            span.end.saturating_sub(start),
+        ),
+    ))
+}
diff --git a/crates/rune/src/worker/mod.rs b/crates/rune/src/worker/mod.rs
