Rename get_source_text to get_source_range. Add new get_source_text which returns a displayable string-like type.

clippy_lints/src/matches/single_match.rs

@@ -22,7 +22,7 @@ use super::{MATCH_BOOL, SINGLE_MATCH, SINGLE_MATCH_ELSE};
 /// span, e.g. a string literal `"//"`, but we know that this isn't the case for empty
 /// match arms.
 fn empty_arm_has_comment(cx: &LateContext<'_>, span: Span) -> bool {
-    if let Some(ff) = span.get_source_text(cx)
+    if let Some(ff) = span.get_source_range(cx)
         && let Some(text) = ff.as_str()
     {
         text.as_bytes().windows(2).any(|w| w == b"//" || w == b"/*")

clippy_utils/src/consts.rs

@@ -687,7 +687,7 @@ impl<'tcx> ConstEvalCtxt<'tcx> {
                 if let Some(expr_span) = walk_span_to_context(expr.span, span.ctxt)
                     && let expr_lo = expr_span.lo()
                     && expr_lo >= span.lo
-                    && let Some(src) = (span.lo..expr_lo).get_source_text(&self.tcx)
+                    && let Some(src) = (span.lo..expr_lo).get_source_range(&self.tcx)
                     && let Some(src) = src.as_str()
                 {
                     use rustc_lexer::TokenKind::{BlockComment, LineComment, OpenBrace, Semi, Whitespace};

clippy_utils/src/hir_utils.rs

@@ -1191,9 +1191,9 @@ fn eq_span_tokens(
     pred: impl Fn(TokenKind) -> bool,
 ) -> bool {
     fn f(cx: &LateContext<'_>, left: Range<BytePos>, right: Range<BytePos>, pred: impl Fn(TokenKind) -> bool) -> bool {
-        if let Some(lsrc) = left.get_source_text(cx)
+        if let Some(lsrc) = left.get_source_range(cx)
             && let Some(lsrc) = lsrc.as_str()
-            && let Some(rsrc) = right.get_source_text(cx)
+            && let Some(rsrc) = right.get_source_range(cx)
             && let Some(rsrc) = rsrc.as_str()
         {
             let pred = |t: &(_, _)| pred(t.0);

clippy_utils/src/source.rs

@@ -16,7 +16,7 @@ use rustc_span::{
 };
 use std::borrow::Cow;
 use std::fmt;
-use std::ops::Range;
+use std::ops::{Deref, Range};
 
 pub trait HasSession {
     fn sess(&self) -> &Session;
@@ -94,10 +94,16 @@ impl IntoSpan for Range<BytePos> {
 }
 
 pub trait SpanRangeExt: SpanRange {
+    /// Attempts to get a handle to the source text. Returns `None` if either the span is malformed,
+    /// or the source text is not accessible.
+    fn get_source_text(self, cx: &impl HasSession) -> Option<SourceText> {
+        get_source_range(cx.sess().source_map(), self.into_range()).and_then(SourceText::new)
+    }
+
     /// Gets the source file, and range in the file, of the given span. Returns `None` if the span
     /// extends through multiple files, or is malformed.
-    fn get_source_text(self, cx: &impl HasSession) -> Option<SourceFileRange> {
-        get_source_text(cx.sess().source_map(), self.into_range())
+    fn get_source_range(self, cx: &impl HasSession) -> Option<SourceFileRange> {
+        get_source_range(cx.sess().source_map(), self.into_range())
     }
 
     /// Calls the given function with the source text referenced and returns the value. Returns
@@ -144,21 +150,49 @@ pub trait SpanRangeExt: SpanRange {
     fn trim_start(self, cx: &impl HasSession) -> Range<BytePos> {
         trim_start(cx.sess().source_map(), self.into_range())
     }
-
-    /// Writes the referenced source text to the given writer. Will return `Err` if the source text
-    /// could not be retrieved.
-    fn write_source_text_to(self, cx: &impl HasSession, dst: &mut impl fmt::Write) -> fmt::Result {
-        write_source_text_to(cx.sess().source_map(), self.into_range(), dst)
-    }
-
-    /// Extracts the referenced source text as an owned string.
-    fn source_text_to_string(self, cx: &impl HasSession) -> Option<String> {
-        self.with_source_text(cx, ToOwned::to_owned)
-    }
 }
 impl<T: SpanRange> SpanRangeExt for T {}
 
-fn get_source_text(sm: &SourceMap, sp: Range<BytePos>) -> Option<SourceFileRange> {
+/// Handle to a range of text in a source file.
+pub struct SourceText(SourceFileRange);
+impl SourceText {
+    /// Takes ownership of the source file handle if the source text is accessible.
+    pub fn new(text: SourceFileRange) -> Option<Self> {
+        if text.as_str().is_some() {
+            Some(Self(text))
+        } else {
+            None
+        }
+    }
+
+    /// Gets the source text.
+    pub fn as_str(&self) -> &str {
+        self.0.as_str().unwrap()
+    }
+
+    /// Converts this into an owned string.
+    pub fn to_owned(&self) -> String {
+        self.as_str().to_owned()
+    }
+}
+impl Deref for SourceText {
+    type Target = str;
+    fn deref(&self) -> &Self::Target {
+        self.as_str()
+    }
+}
+impl AsRef<str> for SourceText {
+    fn as_ref(&self) -> &str {
+        self.as_str()
+    }
+}
+impl fmt::Display for SourceText {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.as_str().fmt(f)
+    }
+}
+
+fn get_source_range(sm: &SourceMap, sp: Range<BytePos>) -> Option<SourceFileRange> {
     let start = sm.lookup_byte_offset(sp.start);
     let end = sm.lookup_byte_offset(sp.end);
     if !Lrc::ptr_eq(&start.sf, &end.sf) || start.pos > end.pos {
@@ -169,7 +203,7 @@ fn get_source_text(sm: &SourceMap, sp: Range<BytePos>) -> Option<SourceFileRange
 }
 
 fn with_source_text<T>(sm: &SourceMap, sp: Range<BytePos>, f: impl for<'a> FnOnce(&'a str) -> T) -> Option<T> {
-    if let Some(src) = get_source_text(sm, sp)
+    if let Some(src) = get_source_range(sm, sp)
         && let Some(src) = src.as_str()
     {
         Some(f(src))
@@ -183,7 +217,7 @@ fn with_source_text_and_range<T>(
     sp: Range<BytePos>,
     f: impl for<'a> FnOnce(&'a str, Range<usize>) -> T,
 ) -> Option<T> {
-    if let Some(src) = get_source_text(sm, sp)
+    if let Some(src) = get_source_range(sm, sp)
         && let Some(text) = &src.sf.src
     {
         Some(f(text, src.range))
@@ -198,7 +232,7 @@ fn map_range(
     sp: Range<BytePos>,
     f: impl for<'a> FnOnce(&'a str, Range<usize>) -> Option<Range<usize>>,
 ) -> Option<Range<BytePos>> {
-    if let Some(src) = get_source_text(sm, sp.clone())
+    if let Some(src) = get_source_range(sm, sp.clone())
         && let Some(text) = &src.sf.src
         && let Some(range) = f(text, src.range.clone())
     {
@@ -232,13 +266,6 @@ fn trim_start(sm: &SourceMap, sp: Range<BytePos>) -> Range<BytePos> {
     .unwrap_or(sp)
 }
 
-fn write_source_text_to(sm: &SourceMap, sp: Range<BytePos>, dst: &mut impl fmt::Write) -> fmt::Result {
-    match with_source_text(sm, sp, |src| dst.write_str(src)) {
-        Some(x) => x,
-        None => Err(fmt::Error),
-    }
-}
-
 pub struct SourceFileRange {
     pub sf: Lrc<SourceFile>,
     pub range: Range<usize>,