Adds associated functions for NewlineStyle (#1894)

* adds functions and tests for newline style

Author: eureka-cpu

sway-fmt-v2/src/config/whitespace.rs

@@ -1,7 +1,7 @@
 //! Standard system and editor whitespace configuration options. Advanced whitespace options will be deferred to their corresponding sub-classes.
 use serde::{Deserialize, Serialize};
 
-use crate::constants::{DEFAULT_MAX_LINE_WIDTH, DEFAULT_TAB_SPACES};
+use crate::constants::{CARRIAGE_RETURN, DEFAULT_MAX_LINE_WIDTH, DEFAULT_TAB_SPACES, LINE_FEED};
 
 use super::user_opts::WhitespaceOptions;
 
@@ -45,6 +45,16 @@ impl Whitespace {
     }
 }
 
+/// Handling of line indentation for expressions or items.
+#[derive(Serialize, Deserialize, Debug, Copy, Clone)]
+pub enum IndentStyle {
+    /// First line on the same line as the opening brace, all lines aligned with
+    /// the first line.
+    Visual,
+    /// First line is on a new line and all lines align with **block** indent.
+    Block,
+}
+
 /// Handling of which OS new-line style should be applied.
 #[derive(Serialize, Deserialize, Debug, Copy, Clone)]
 pub enum NewlineStyle {
@@ -58,12 +68,43 @@ pub enum NewlineStyle {
     Native,
 }
 
-/// Handling of line indentation for expressions or items.
-#[derive(Serialize, Deserialize, Debug, Copy, Clone)]
-pub enum IndentStyle {
-    /// First line on the same line as the opening brace, all lines aligned with
-    /// the first line.
-    Visual,
-    /// First line is on a new line and all lines align with **block** indent.
-    Block,
+/// The definitive system type for `[NewlineStyle]`.
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+pub enum NewlineSystemType {
+    Windows,
+    Unix,
+}
+
+impl NewlineSystemType {
+    pub fn get_newline_style(newline_style: NewlineStyle, raw_input_text: &str) -> Self {
+        match newline_style {
+            NewlineStyle::Auto => Self::auto_detect_newline_style(raw_input_text),
+            NewlineStyle::Native => Self::native_newline_style(),
+            NewlineStyle::Windows => Self::Windows,
+            NewlineStyle::Unix => Self::Unix,
+        }
+    }
+
+    pub fn auto_detect_newline_style(raw_input_text: &str) -> Self {
+        let first_line_feed_pos = raw_input_text.chars().position(|ch| ch == LINE_FEED);
+        match first_line_feed_pos {
+            Some(first_line_feed_pos) => {
+                let char_before_line_feed_pos = first_line_feed_pos.saturating_sub(1);
+                let char_before_line_feed = raw_input_text.chars().nth(char_before_line_feed_pos);
+                match char_before_line_feed {
+                    Some(CARRIAGE_RETURN) => Self::Windows,
+                    _ => Self::Unix,
+                }
+            }
+            None => Self::native_newline_style(),
+        }
+    }
+
+    fn native_newline_style() -> Self {
+        if cfg!(windows) {
+            Self::Windows
+        } else {
+            Self::Unix
+        }
+    }
 }

sway-fmt-v2/src/constants.rs

@@ -47,3 +47,9 @@ pub const DEFAULT_ENUM_VARIANT_ALIGN_THRESHOLD: usize = 0;
 
 /// Default max length of comments.
 pub const DEFAULT_MAX_COMMENT_WIDTH: usize = 80;
+
+/////NEWLINE_STYLE/////
+pub const LINE_FEED: char = '\n';
+pub const CARRIAGE_RETURN: char = '\r';
+pub const WINDOWS_NEWLINE: &str = "\r\n";
+pub const UNIX_NEWLINE: &str = "\n";

sway-fmt-v2/src/lib.rs

@@ -9,6 +9,7 @@ mod constants;
 mod error;
 mod fmt;
 mod items;
+mod newline_style;
 
 pub use crate::fmt::Formatter;
 pub use error::FormatterError;

sway-fmt-v2/src/newline_style.rs

@@ -0,0 +1,208 @@
+//! Functions and tests that determine and apply the user defined [NewlineStyle].
+use crate::{
+    config::whitespace::{NewlineStyle, NewlineSystemType},
+    constants::{CARRIAGE_RETURN, LINE_FEED, UNIX_NEWLINE, WINDOWS_NEWLINE},
+};
+
+/// Apply this newline style to the formatted text. When the style is set
+/// to `Auto`, the `raw_input_text` is used to detect the existing line
+/// endings.
+///
+/// If the style is set to `Auto` and `raw_input_text` contains no
+/// newlines, the `Native` style will be used.
+pub(crate) fn apply_newline_style(
+    newline_style: NewlineStyle,
+    formatted_text: &mut String,
+    raw_input_text: &str,
+) {
+    *formatted_text = match NewlineSystemType::get_newline_style(newline_style, raw_input_text) {
+        NewlineSystemType::Windows => convert_to_windows_newlines(formatted_text),
+        NewlineSystemType::Unix => convert_to_unix_newlines(formatted_text),
+    }
+}
+
+fn convert_to_windows_newlines(formatted_text: &String) -> String {
+    let mut transformed = String::with_capacity(2 * formatted_text.capacity());
+    let mut chars = formatted_text.chars().peekable();
+    while let Some(current_char) = chars.next() {
+        let next_char = chars.peek();
+        match current_char {
+            LINE_FEED => transformed.push_str(WINDOWS_NEWLINE),
+            CARRIAGE_RETURN if next_char == Some(&LINE_FEED) => {}
+            current_char => transformed.push(current_char),
+        }
+    }
+    transformed
+}
+
+fn convert_to_unix_newlines(formatted_text: &str) -> String {
+    formatted_text.replace(WINDOWS_NEWLINE, UNIX_NEWLINE)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn auto_detects_unix_newlines() {
+        assert_eq!(
+            NewlineSystemType::Unix,
+            NewlineSystemType::auto_detect_newline_style("One\nTwo\nThree")
+        );
+    }
+
+    #[test]
+    fn auto_detects_windows_newlines() {
+        assert_eq!(
+            NewlineSystemType::Windows,
+            NewlineSystemType::auto_detect_newline_style("One\r\nTwo\r\nThree")
+        );
+    }
+
+    #[test]
+    fn auto_detects_windows_newlines_with_multibyte_char_on_first_line() {
+        assert_eq!(
+            NewlineSystemType::Windows,
+            NewlineSystemType::auto_detect_newline_style("A 🎢 of a first line\r\nTwo\r\nThree")
+        );
+    }
+
+    #[test]
+    fn falls_back_to_native_newlines_if_no_newlines_are_found() {
+        let expected_newline_style = if cfg!(windows) {
+            NewlineSystemType::Windows
+        } else {
+            NewlineSystemType::Unix
+        };
+        assert_eq!(
+            expected_newline_style,
+            NewlineSystemType::auto_detect_newline_style("One Two Three")
+        );
+    }
+
+    #[test]
+    fn auto_detects_and_applies_unix_newlines() {
+        let formatted_text = "One\nTwo\nThree";
+        let raw_input_text = "One\nTwo\nThree";
+
+        let mut out = String::from(formatted_text);
+        apply_newline_style(NewlineStyle::Auto, &mut out, raw_input_text);
+        assert_eq!("One\nTwo\nThree", &out, "auto should detect 'lf'");
+    }
+
+    #[test]
+    fn auto_detects_and_applies_windows_newlines() {
+        let formatted_text = "One\nTwo\nThree";
+        let raw_input_text = "One\r\nTwo\r\nThree";
+
+        let mut out = String::from(formatted_text);
+        apply_newline_style(NewlineStyle::Auto, &mut out, raw_input_text);
+        assert_eq!("One\r\nTwo\r\nThree", &out, "auto should detect 'crlf'");
+    }
+
+    #[test]
+    fn auto_detects_and_applies_native_newlines() {
+        let formatted_text = "One\nTwo\nThree";
+        let raw_input_text = "One Two Three";
+
+        let mut out = String::from(formatted_text);
+        apply_newline_style(NewlineStyle::Auto, &mut out, raw_input_text);
+
+        if cfg!(windows) {
+            assert_eq!(
+                "One\r\nTwo\r\nThree", &out,
+                "auto-native-windows should detect 'crlf'"
+            );
+        } else {
+            assert_eq!(
+                "One\nTwo\nThree", &out,
+                "auto-native-unix should detect 'lf'"
+            );
+        }
+    }
+
+    #[test]
+    fn applies_unix_newlines() {
+        test_newlines_are_applied_correctly(
+            "One\r\nTwo\nThree",
+            "One\nTwo\nThree",
+            NewlineStyle::Unix,
+        );
+    }
+
+    #[test]
+    fn applying_unix_newlines_changes_nothing_for_unix_newlines() {
+        let formatted_text = "One\nTwo\nThree";
+        test_newlines_are_applied_correctly(formatted_text, formatted_text, NewlineStyle::Unix);
+    }
+
+    #[test]
+    fn applies_unix_newlines_to_string_with_unix_and_windows_newlines() {
+        test_newlines_are_applied_correctly(
+            "One\r\nTwo\r\nThree\nFour",
+            "One\nTwo\nThree\nFour",
+            NewlineStyle::Unix,
+        );
+    }
+
+    #[test]
+    fn applies_windows_newlines_to_string_with_unix_and_windows_newlines() {
+        test_newlines_are_applied_correctly(
+            "One\nTwo\nThree\r\nFour",
+            "One\r\nTwo\r\nThree\r\nFour",
+            NewlineStyle::Windows,
+        );
+    }
+
+    #[test]
+    fn applying_windows_newlines_changes_nothing_for_windows_newlines() {
+        let formatted_text = "One\r\nTwo\r\nThree";
+        test_newlines_are_applied_correctly(formatted_text, formatted_text, NewlineStyle::Windows);
+    }
+
+    #[test]
+    fn keeps_carriage_returns_when_applying_windows_newlines_to_str_with_unix_newlines() {
+        test_newlines_are_applied_correctly(
+            "One\nTwo\nThree\rDrei",
+            "One\r\nTwo\r\nThree\rDrei",
+            NewlineStyle::Windows,
+        );
+    }
+
+    #[test]
+    fn keeps_carriage_returns_when_applying_unix_newlines_to_str_with_unix_newlines() {
+        test_newlines_are_applied_correctly(
+            "One\nTwo\nThree\rDrei",
+            "One\nTwo\nThree\rDrei",
+            NewlineStyle::Unix,
+        );
+    }
+
+    #[test]
+    fn keeps_carriage_returns_when_applying_windows_newlines_to_str_with_windows_newlines() {
+        test_newlines_are_applied_correctly(
+            "One\r\nTwo\r\nThree\rDrei",
+            "One\r\nTwo\r\nThree\rDrei",
+            NewlineStyle::Windows,
+        );
+    }
+
+    #[test]
+    fn keeps_carriage_returns_when_applying_unix_newlines_to_str_with_windows_newlines() {
+        test_newlines_are_applied_correctly(
+            "One\r\nTwo\r\nThree\rDrei",
+            "One\nTwo\nThree\rDrei",
+            NewlineStyle::Unix,
+        );
+    }
+
+    fn test_newlines_are_applied_correctly(
+        input: &str,
+        expected: &str,
+        newline_style: NewlineStyle,
+    ) {
+        let mut out = String::from(input);
+        apply_newline_style(newline_style, &mut out, input);
+        assert_eq!(expected, &out);
+    }
+}