Make path::resolve a method on ExtCtxt

Author: jonas-schievink

src/libsyntax/ext/base.rs

@@ -1,6 +1,6 @@
 use crate::ast::{self, Attribute, Name, PatKind};
 use crate::attr::{HasAttrs, Stability, Deprecation};
-use crate::source_map::{SourceMap, Spanned, respan};
+use crate::source_map::{SourceMap, Spanned, FileName, respan};
 use crate::edition::Edition;
 use crate::ext::expand::{self, AstFragment, Invocation};
 use crate::ext::hygiene::{ExpnId, SyntaxContext, Transparency};
@@ -889,6 +889,31 @@ impl<'a> ExtCtxt<'a> {
     pub fn check_unused_macros(&self) {
         self.resolver.check_unused_macros();
     }
+
+    /// Resolve a path mentioned inside Rust code.
+    ///
+    /// This unifies the logic used for resolving `include_X!`, and `#[doc(include)]` file paths.
+    ///
+    /// Returns an absolute path to the file that `path` refers to.
+    pub fn resolve_path(&self, path: impl Into<PathBuf>, span: Span) -> PathBuf {
+        let path = path.into();
+
+        // Relative paths are resolved relative to the file in which they are found
+        // after macro expansion (that is, they are unhygienic).
+        if !path.is_absolute() {
+            let callsite = span.source_callsite();
+            let mut result = match self.source_map().span_to_unmapped_path(callsite) {
+                FileName::Real(path) => path,
+                FileName::DocTest(path, _) => path,
+                other => panic!("cannot resolve relative path in non-file source `{}`", other),
+            };
+            result.pop();
+            result.push(path);
+            result
+        } else {
+            path
+        }
+    }
 }
 
 /// Extracts a string literal from the macro expanded version of `expr`,

src/libsyntax/ext/expand.rs

@@ -17,7 +17,6 @@ use crate::symbol::{sym, Symbol};
 use crate::tokenstream::{TokenStream, TokenTree};
 use crate::visit::{self, Visitor};
 use crate::util::map_in_place::MapInPlace;
-use crate::util::path;
 
 use errors::{Applicability, FatalError};
 use smallvec::{smallvec, SmallVec};
@@ -1254,7 +1253,7 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
                         return noop_visit_attribute(at, self);
                     }
 
-                    let filename = path::resolve(&*file.as_str(), it.span(), self.cx.source_map());
+                    let filename = self.cx.resolve_path(&*file.as_str(), it.span());
                     match fs::read_to_string(&filename) {
                         Ok(src) => {
                             let src_interned = Symbol::intern(&src);

src/libsyntax/ext/source_util.rs

@@ -6,7 +6,6 @@ use crate::print::pprust;
 use crate::ptr::P;
 use crate::symbol::Symbol;
 use crate::tokenstream;
-use crate::util::path;
 
 use smallvec::SmallVec;
 use syntax_pos::{self, Pos, Span};
@@ -78,7 +77,7 @@ pub fn expand_include<'cx>(cx: &'cx mut ExtCtxt<'_>, sp: Span, tts: &[tokenstrea
         None => return DummyResult::any(sp),
     };
     // The file will be added to the code map by the parser
-    let file = path::resolve(file, sp, cx.source_map());
+    let file = cx.resolve_path(file, sp);
     let directory_ownership = DirectoryOwnership::Owned { relative: None };
     let p = parse::new_sub_parser_from_file(cx.parse_sess(), &file, directory_ownership, None, sp);
 
@@ -115,7 +114,7 @@ pub fn expand_include_str(cx: &mut ExtCtxt<'_>, sp: Span, tts: &[tokenstream::To
         Some(f) => f,
         None => return DummyResult::expr(sp)
     };
-    let file = path::resolve(file, sp, cx.source_map());
+    let file = cx.resolve_path(file, sp);
     match fs::read_to_string(&file) {
         Ok(src) => {
             let interned_src = Symbol::intern(&src);
@@ -143,7 +142,7 @@ pub fn expand_include_bytes(cx: &mut ExtCtxt<'_>, sp: Span, tts: &[tokenstream::
         Some(f) => f,
         None => return DummyResult::expr(sp)
     };
-    let file = path::resolve(file, sp, cx.source_map());
+    let file = cx.resolve_path(file, sp);
     match fs::read(&file) {
         Ok(bytes) => {
             // Add the contents to the source map if it contains UTF-8.

src/libsyntax/lib.rs

@@ -135,7 +135,6 @@ pub mod util {
     #[cfg(test)]
     pub mod parser_testing;
     pub mod map_in_place;
-    pub mod path;
 }
 
 pub mod json;