1 files changed, 105 insertions, 0 deletions
diff --git a/src/tools/rustfmt/src/source_file.rs b/src/tools/rustfmt/src/source_file.rs
new file mode 100644
index 000000000..56d4ab400
--- /dev/null
+++ b/src/tools/rustfmt/src/source_file.rs
@@ -0,0 +1,105 @@
+use std::fs;
+use std::io::{self, Write};
+use std::path::Path;
+
+use crate::config::FileName;
+use crate::emitter::{self, Emitter};
+use crate::parse::session::ParseSess;
+use crate::NewlineStyle;
+
+#[cfg(test)]
+use crate::config::Config;
+#[cfg(test)]
+use crate::create_emitter;
+#[cfg(test)]
+use crate::formatting::FileRecord;
+
+use rustc_data_structures::sync::Lrc;
+
+// Append a newline to the end of each file.
+pub(crate) fn append_newline(s: &mut String) {
+    s.push('\n');
+}
+
+#[cfg(test)]
+pub(crate) fn write_all_files<T>(
+    source_file: &[FileRecord],
+    out: &mut T,
+    config: &Config,
+) -> Result<(), io::Error>
+where
+    T: Write,
+{
+    let mut emitter = create_emitter(config);
+
+    emitter.emit_header(out)?;
+    for &(ref filename, ref text) in source_file {
+        write_file(
+            None,
+            filename,
+            text,
+            out,
+            &mut *emitter,
+            config.newline_style(),
+        )?;
+    }
+    emitter.emit_footer(out)?;
+
+    Ok(())
+}
+
+pub(crate) fn write_file<T>(
+    parse_sess: Option<&ParseSess>,
+    filename: &FileName,
+    formatted_text: &str,
+    out: &mut T,
+    emitter: &mut dyn Emitter,
+    newline_style: NewlineStyle,
+) -> Result<emitter::EmitterResult, io::Error>
+where
+    T: Write,
+{
+    fn ensure_real_path(filename: &FileName) -> &Path {
+        match *filename {
+            FileName::Real(ref path) => path,
+            _ => panic!("cannot format `{}` and emit to files", filename),
+        }
+    }
+
+    impl From<&FileName> for rustc_span::FileName {
+        fn from(filename: &FileName) -> rustc_span::FileName {
+            match filename {
+                FileName::Real(path) => {
+                    rustc_span::FileName::Real(rustc_span::RealFileName::LocalPath(path.to_owned()))
+                }
+                FileName::Stdin => rustc_span::FileName::Custom("stdin".to_owned()),
+            }
+        }
+    }
+
+    // SourceFile's in the SourceMap will always have Unix-style line endings
+    // See: https://github.com/rust-lang/rustfmt/issues/3850
+    // So if the user has explicitly overridden the rustfmt `newline_style`
+    // config and `filename` is FileName::Real, then we must check the file system
+    // to get the original file value in order to detect newline_style conflicts.
+    // Otherwise, parse session is around (cfg(not(test))) and newline_style has been
+    // left as the default value, then try getting source from the parse session
+    // source map instead of hitting the file system. This also supports getting
+    // original text for `FileName::Stdin`.
+    let original_text = if newline_style != NewlineStyle::Auto && *filename != FileName::Stdin {
+        Lrc::new(fs::read_to_string(ensure_real_path(filename))?)
+    } else {
+        match parse_sess.and_then(|sess| sess.get_original_snippet(filename)) {
+            Some(ori) => ori,
+            None => Lrc::new(fs::read_to_string(ensure_real_path(filename))?),
+        }
+    };
+
+    let formatted_file = emitter::FormattedFile {
+        filename,
+        original_text: original_text.as_str(),
+        formatted_text,
+    };
+
+    emitter.emit_formatted_file(out, formatted_file)
+}