Refactor: parse file meta line

In preparation for #392

src/delta.rs

@@ -62,6 +62,7 @@ where
     let mut painter = Painter::new(writer, config);
     let mut minus_file = "".to_string();
     let mut plus_file = "".to_string();
+    let mut file_event = parse::FileEvent::NoEvent;
     let mut state = State::Unknown;
     let mut source = Source::Unknown;
 
@@ -99,7 +100,11 @@ where
         } else if (state == State::FileMeta || source == Source::DiffUnified)
             && (line.starts_with("--- ") || line.starts_with("rename from "))
         {
-            minus_file = parse::get_file_path_from_file_meta_line(&line, source == Source::GitDiff);
+            let parsed_file_meta_line =
+                parse::parse_file_meta_line(&line, source == Source::GitDiff);
+            minus_file = parsed_file_meta_line.0;
+            file_event = parsed_file_meta_line.1;
+
             if source == Source::DiffUnified {
                 state = State::FileMeta;
                 painter.set_syntax(parse::get_file_extension_from_marker_line(&line));
@@ -111,7 +116,9 @@ where
         } else if (state == State::FileMeta || source == Source::DiffUnified)
             && (line.starts_with("+++ ") || line.starts_with("rename to "))
         {
-            plus_file = parse::get_file_path_from_file_meta_line(&line, source == Source::GitDiff);
+            let parsed_file_meta_line =
+                parse::parse_file_meta_line(&line, source == Source::GitDiff);
+            plus_file = parsed_file_meta_line.0;
             painter.set_syntax(parse::get_file_extension_from_file_meta_line_file_path(
                 &plus_file,
             ));
@@ -125,6 +132,7 @@ where
                     &minus_file,
                     &plus_file,
                     config,
+                    &file_event,
                     source == Source::DiffUnified,
                 )?;
                 handled_file_meta_header_line_file_pair = current_file_pair
@@ -288,10 +296,11 @@ fn handle_file_meta_header_line(
     minus_file: &str,
     plus_file: &str,
     config: &Config,
+    file_event: &parse::FileEvent,
     comparing: bool,
 ) -> std::io::Result<()> {
     let line = parse::get_file_change_description_from_file_paths(
-        minus_file, plus_file, comparing, config,
+        minus_file, plus_file, comparing, file_event, config,
     );
     // FIXME: no support for 'raw'
     handle_generic_file_meta_header_line(painter, &line, &line, config)

src/parse.rs

@@ -19,28 +19,36 @@ pub fn get_file_extension_from_marker_line(line: &str) -> Option<&str> {
         .and_then(|file| file.split('.').last())
 }
 
-pub fn get_file_path_from_file_meta_line(line: &str, git_diff_name: bool) -> String {
+#[derive(Debug, PartialEq)]
+pub enum FileEvent {
+    Change,
+    Rename,
+    NoEvent,
+}
+
+pub fn parse_file_meta_line(line: &str, git_diff_name: bool) -> (String, FileEvent) {
     match line {
         line if line.starts_with("--- ") || line.starts_with("+++ ") => {
             let offset = 4;
-            match &line[offset..] {
+            let file = match &line[offset..] {
                 path if path == "/dev/null" => "/dev/null",
                 path if git_diff_name && DIFF_PREFIXES.iter().any(|s| path.starts_with(s)) => {
                     &path[2..]
                 }
                 path if git_diff_name => &path,
                 path => path.split('\t').next().unwrap_or(""),
             }
+            .to_string();
+            (file, FileEvent::Change)
         }
         line if line.starts_with("rename from ") => {
-            &line[12..] // "rename from ".len()
+            (line[12..].to_string(), FileEvent::Rename) // "rename from ".len()
         }
         line if line.starts_with("rename to ") => {
-            &line[10..] // "rename to ".len()
+            (line[10..].to_string(), FileEvent::Rename) // "rename to ".len()
         }
-        _ => "",
+        _ => ("".to_string(), FileEvent::NoEvent),
     }
-    .to_string()
 }
 
 pub fn get_file_extension_from_file_meta_line_file_path(path: &str) -> Option<&str> {
@@ -55,6 +63,7 @@ pub fn get_file_change_description_from_file_paths(
     minus_file: &str,
     plus_file: &str,
     comparing: bool,
+    file_event: &FileEvent,
     config: &Config,
 ) -> String {
     if comparing {
@@ -92,7 +101,10 @@ pub fn get_file_change_description_from_file_paths(
             ),
             (minus_file, plus_file) => format!(
                 "{}{} ⟶   {}",
-                format_label(&config.file_renamed_label),
+                format_label(match file_event {
+                    FileEvent::Rename => &config.file_renamed_label,
+                    _ => "",
+                }),
                 format_file(minus_file),
                 format_file(plus_file)
             ),
@@ -224,74 +236,77 @@ mod tests {
     #[test]
     fn test_get_file_path_from_git_file_meta_line() {
         assert_eq!(
-            get_file_path_from_file_meta_line("--- /dev/null", true),
-            "/dev/null"
+            parse_file_meta_line("--- /dev/null", true),
+            ("/dev/null".to_string(), FileEvent::Change)
         );
         for prefix in &DIFF_PREFIXES {
             assert_eq!(
-                get_file_path_from_file_meta_line(&format!("--- {}src/delta.rs", prefix), true),
-                "src/delta.rs"
+                parse_file_meta_line(&format!("--- {}src/delta.rs", prefix), true),
+                ("src/delta.rs".to_string(), FileEvent::Change)
             );
         }
         assert_eq!(
-            get_file_path_from_file_meta_line("--- src/delta.rs", true),
-            "src/delta.rs"
+            parse_file_meta_line("--- src/delta.rs", true),
+            ("src/delta.rs".to_string(), FileEvent::Change)
         );
         assert_eq!(
-            get_file_path_from_file_meta_line("+++ src/delta.rs", true),
-            "src/delta.rs"
+            parse_file_meta_line("+++ src/delta.rs", true),
+            ("src/delta.rs".to_string(), FileEvent::Change)
         );
     }
 
     #[test]
     fn test_get_file_path_from_git_file_meta_line_containing_spaces() {
         assert_eq!(
-            get_file_path_from_file_meta_line("+++ a/my src/delta.rs", true),
-            "my src/delta.rs"
+            parse_file_meta_line("+++ a/my src/delta.rs", true),
+            ("my src/delta.rs".to_string(), FileEvent::Change)
         );
         assert_eq!(
-            get_file_path_from_file_meta_line("+++ my src/delta.rs", true),
-            "my src/delta.rs"
+            parse_file_meta_line("+++ my src/delta.rs", true),
+            ("my src/delta.rs".to_string(), FileEvent::Change)
         );
         assert_eq!(
-            get_file_path_from_file_meta_line("+++ a/src/my delta.rs", true),
-            "src/my delta.rs"
+            parse_file_meta_line("+++ a/src/my delta.rs", true),
+            ("src/my delta.rs".to_string(), FileEvent::Change)
         );
         assert_eq!(
-            get_file_path_from_file_meta_line("+++ a/my src/my delta.rs", true),
-            "my src/my delta.rs"
+            parse_file_meta_line("+++ a/my src/my delta.rs", true),
+            ("my src/my delta.rs".to_string(), FileEvent::Change)
         );
         assert_eq!(
-            get_file_path_from_file_meta_line("+++ b/my src/my enough/my delta.rs", true),
-            "my src/my enough/my delta.rs"
+            parse_file_meta_line("+++ b/my src/my enough/my delta.rs", true),
+            (
+                "my src/my enough/my delta.rs".to_string(),
+                FileEvent::Change
+            )
         );
     }
 
     #[test]
     fn test_get_file_path_from_git_file_meta_line_rename() {
         assert_eq!(
-            get_file_path_from_file_meta_line("rename from nospace/file2.el", true),
-            "nospace/file2.el"
+            parse_file_meta_line("rename from nospace/file2.el", true),
+            ("nospace/file2.el".to_string(), FileEvent::Rename)
         );
     }
 
     #[test]
     fn test_get_file_path_from_git_file_meta_line_rename_containing_spaces() {
         assert_eq!(
-            get_file_path_from_file_meta_line("rename from with space/file1.el", true),
-            "with space/file1.el"
+            parse_file_meta_line("rename from with space/file1.el", true),
+            ("with space/file1.el".to_string(), FileEvent::Rename)
         );
     }
 
     #[test]
-    fn test_get_file_path_from_file_meta_line() {
+    fn test_parse_file_meta_line() {
         assert_eq!(
-            get_file_path_from_file_meta_line("--- src/delta.rs", false),
-            "src/delta.rs"
+            parse_file_meta_line("--- src/delta.rs", false),
+            ("src/delta.rs".to_string(), FileEvent::Change)
         );
         assert_eq!(
-            get_file_path_from_file_meta_line("+++ src/delta.rs", false),
-            "src/delta.rs"
+            parse_file_meta_line("+++ src/delta.rs", false),
+            ("src/delta.rs".to_string(), FileEvent::Change)
         );
     }