closer: "\"",
line_start: " ",
line_end: "\\",
- shape: shape,
+ shape,
trim_end: false,
- config: config,
+ config,
}
}
+
+ /// Returns the maximum number of graphemes that is possible on a line while taking the
+ /// indentation into account.
+ ///
+ /// If we cannot put at least a single character per line, the rewrite won't succeed.
+ fn max_chars_with_indent(&self) -> Option<usize> {
+ Some(
+ self.shape
+ .width
+ .checked_sub(self.opener.len() + self.line_end.len() + 1)?
+ + 1,
+ )
+ }
+
+ /// Like max_chars_with_indent but the indentation is not substracted.
+ /// This allows to fit more graphemes from the string on a line when
+ /// SnippetState::Overflow.
+ fn max_chars_without_indent(&self) -> Option<usize> {
+ Some(self.config.max_width().checked_sub(self.line_end.len())?)
+ }
}
-// FIXME: simplify this!
pub fn rewrite_string<'a>(orig: &str, fmt: &StringFormat<'a>) -> Option<String> {
+ let max_chars_with_indent = fmt.max_chars_with_indent()?;
+ let max_chars_without_indent = fmt.max_chars_without_indent()?;
+ let indent = fmt.shape.indent.to_string_with_newline(fmt.config);
+
// Strip line breaks.
- let re = Regex::new(r"([^\\](\\\\)*)\\[\n\r][[:space:]]*").unwrap();
- let stripped_str = re.replace_all(orig, "$1");
+ // With this regex applied, all remaining whitespaces are significant
+ let strip_line_breaks_re = Regex::new(r"([^\\](\\\\)*)\\[\n\r][[:space:]]*").unwrap();
+ let stripped_str = strip_line_breaks_re.replace_all(orig, "$1");
let graphemes = UnicodeSegmentation::graphemes(&*stripped_str, false).collect::<Vec<&str>>();
- let shape = fmt.shape.visual_indent(0);
- let indent = shape.indent.to_string(fmt.config);
- let punctuation = ":,;.";
// `cur_start` is the position in `orig` of the start of the current line.
let mut cur_start = 0;
);
result.push_str(fmt.opener);
- let ender_length = fmt.line_end.len();
- // If we cannot put at least a single character per line, the rewrite won't
- // succeed.
- let max_chars = try_opt!(shape.width.checked_sub(fmt.opener.len() + ender_length + 1)) + 1;
-
- // Snip a line at a time from `orig` until it is used up. Push the snippet
+ // Snip a line at a time from `stripped_str` until it is used up. Push the snippet
// onto result.
- 'outer: loop {
- // `cur_end` will be where we break the line, as an offset into `orig`.
- // Initialised to the maximum it could be (which may be beyond `orig`).
- let mut cur_end = cur_start + max_chars;
-
- // We can fit the rest of the string on this line, so we're done.
- if cur_end >= graphemes.len() {
- let line = &graphemes[cur_start..].join("");
- result.push_str(line);
- break 'outer;
+ let mut cur_max_chars = max_chars_with_indent;
+ loop {
+ // All the input starting at cur_start fits on the current line
+ if graphemes.len() - cur_start <= cur_max_chars {
+ result.push_str(&graphemes[cur_start..].join(""));
+ break;
}
- // Push cur_end left until we reach whitespace (or the line is too small).
- while !graphemes[cur_end - 1].trim().is_empty() {
- cur_end -= 1;
- if cur_end < cur_start + MIN_STRING {
- // We couldn't find whitespace before the string got too small.
- // So start again at the max length and look for punctuation.
- cur_end = cur_start + max_chars;
- while !punctuation.contains(graphemes[cur_end - 1]) {
- cur_end -= 1;
-
- // If we can't break at whitespace or punctuation, grow the string instead.
- if cur_end < cur_start + MIN_STRING {
- cur_end = cur_start + max_chars;
- while !(punctuation.contains(graphemes[cur_end - 1])
- || graphemes[cur_end - 1].trim().is_empty())
- {
- if cur_end >= graphemes.len() {
- let line = &graphemes[cur_start..].join("");
- result.push_str(line);
- break 'outer;
- }
- cur_end += 1;
- }
- break;
- }
- }
+ // The input starting at cur_start needs to be broken
+ match break_string(cur_max_chars, fmt.trim_end, &graphemes[cur_start..]) {
+ SnippetState::LineEnd(line, len) => {
+ result.push_str(&line);
+ result.push_str(fmt.line_end);
+ result.push_str(&indent);
+ result.push_str(fmt.line_start);
+ cur_max_chars = max_chars_with_indent;
+ cur_start += len;
+ }
+ SnippetState::Overflow(line, len) => {
+ result.push_str(&line);
+ cur_max_chars = max_chars_without_indent;
+ cur_start += len;
+ }
+ SnippetState::EndOfInput(line) => {
+ result.push_str(&line);
break;
}
}
- // Make sure there is no whitespace to the right of the break.
- while cur_end < stripped_str.len() && graphemes[cur_end].trim().is_empty() {
- cur_end += 1;
+ }
+
+ result.push_str(fmt.closer);
+ wrap_str(result, fmt.config.max_width(), fmt.shape)
+}
+
+/// Result of breaking a string so it fits in a line and the state it ended in.
+/// The state informs about what to do with the snippet and how to continue the breaking process.
+#[derive(Debug, PartialEq)]
+enum SnippetState {
+ /// The input could not be broken and so rewriting the string is finished.
+ EndOfInput(String),
+ /// The input could be broken and the returned snippet should be ended with a
+ /// `[StringFormat::line_end]`. The next snippet needs to be indented.
+ LineEnd(String, usize),
+ /// The input could be broken but the returned snippet should not be ended with a
+ /// `[StringFormat::line_end]` because the whitespace is significant. Therefore, the next
+ /// snippet should not be indented.
+ Overflow(String, usize),
+}
+
+/// Break the input string at a boundary character around the offset `max_chars`. A boundary
+/// character is either a punctuation or a whitespace.
+fn break_string(max_chars: usize, trim_end: bool, input: &[&str]) -> SnippetState {
+ let break_at = |index /* grapheme at index is included */| {
+ // Take in any whitespaces to the left/right of `input[index]` and
+ // check if there is a line feed, in which case whitespaces needs to be kept.
+ let mut index_minus_ws = index;
+ for (i, grapheme) in input[0..=index].iter().enumerate().rev() {
+ if !trim_end && is_line_feed(grapheme) {
+ return SnippetState::Overflow(input[0..=i].join("").to_string(), i + 1);
+ } else if !is_whitespace(grapheme) {
+ index_minus_ws = i;
+ break;
+ }
+ }
+ let mut index_plus_ws = index;
+ for (i, grapheme) in input[index + 1..].iter().enumerate() {
+ if !trim_end && is_line_feed(grapheme) {
+ return SnippetState::Overflow(
+ input[0..=index + 1 + i].join("").to_string(),
+ index + 2 + i,
+ );
+ } else if !is_whitespace(grapheme) {
+ index_plus_ws = index + i;
+ break;
+ }
}
- // Make the current line and add it on to result.
- let raw_line = graphemes[cur_start..cur_end].join("");
- let line = if fmt.trim_end {
- raw_line.trim()
+ if trim_end {
+ SnippetState::LineEnd(
+ input[0..=index_minus_ws].join("").to_string(),
+ index_plus_ws + 1,
+ )
} else {
- raw_line.as_str()
- };
-
- result.push_str(line);
- result.push_str(fmt.line_end);
- result.push('\n');
- result.push_str(&indent);
- result.push_str(fmt.line_start);
+ SnippetState::LineEnd(
+ input[0..=index_plus_ws].join("").to_string(),
+ index_plus_ws + 1,
+ )
+ }
+ };
- // The next line starts where the current line ends.
- cur_start = cur_end;
+ // Find the position in input for breaking the string
+ match input[0..max_chars]
+ .iter()
+ .rposition(|grapheme| is_whitespace(grapheme))
+ {
+ // Found a whitespace and what is on its left side is big enough.
+ Some(index) if index >= MIN_STRING => break_at(index),
+ // No whitespace found, try looking for a punctuation instead
+ _ => match input[0..max_chars]
+ .iter()
+ .rposition(|grapheme| is_punctuation(grapheme))
+ {
+ // Found a punctuation and what is on its left side is big enough.
+ Some(index) if index >= MIN_STRING => break_at(index),
+ // Either no boundary character was found to the left of `input[max_chars]`, or the line
+ // got too small. We try searching for a boundary character to the right.
+ _ => match input[max_chars..]
+ .iter()
+ .position(|grapheme| is_whitespace(grapheme) || is_punctuation(grapheme))
+ {
+ // A boundary was found after the line limit
+ Some(index) => break_at(max_chars + index),
+ // No boundary to the right, the input cannot be broken
+ None => SnippetState::EndOfInput(input.join("").to_string()),
+ },
+ },
}
+}
- result.push_str(fmt.closer);
- wrap_str(result, fmt.config.max_width(), fmt.shape)
+fn is_line_feed(grapheme: &str) -> bool {
+ grapheme.as_bytes()[0] == b'\n'
+}
+
+fn is_whitespace(grapheme: &str) -> bool {
+ grapheme.chars().all(|c| c.is_whitespace())
+}
+
+fn is_punctuation(grapheme: &str) -> bool {
+ match grapheme.as_bytes()[0] {
+ b':' | b',' | b';' | b'.' => true,
+ _ => false,
+ }
}
#[cfg(test)]
mod test {
- use super::{rewrite_string, StringFormat};
+ use super::{break_string, rewrite_string, SnippetState, StringFormat};
use shape::{Indent, Shape};
+ use unicode_segmentation::UnicodeSegmentation;
#[test]
fn issue343() {
let fmt = StringFormat::new(Shape::legacy(2, Indent::empty()), &config);
rewrite_string("eq_", &fmt);
}
+
+ #[test]
+ fn should_break_on_whitespace() {
+ let string = "Placerat felis. Mauris porta ante sagittis purus.";
+ let graphemes = UnicodeSegmentation::graphemes(&*string, false).collect::<Vec<&str>>();
+ assert_eq!(
+ break_string(20, false, &graphemes[..]),
+ SnippetState::LineEnd("Placerat felis. ".to_string(), 16)
+ );
+ assert_eq!(
+ break_string(20, true, &graphemes[..]),
+ SnippetState::LineEnd("Placerat felis.".to_string(), 16)
+ );
+ }
+
+ #[test]
+ fn should_break_on_punctuation() {
+ let string = "Placerat_felis._Mauris_porta_ante_sagittis_purus.";
+ let graphemes = UnicodeSegmentation::graphemes(&*string, false).collect::<Vec<&str>>();
+ assert_eq!(
+ break_string(20, false, &graphemes[..]),
+ SnippetState::LineEnd("Placerat_felis.".to_string(), 15)
+ );
+ }
+
+ #[test]
+ fn should_break_forward() {
+ let string = "Venenatis_tellus_vel_tellus. Aliquam aliquam dolor at justo.";
+ let graphemes = UnicodeSegmentation::graphemes(&*string, false).collect::<Vec<&str>>();
+ assert_eq!(
+ break_string(20, false, &graphemes[..]),
+ SnippetState::LineEnd("Venenatis_tellus_vel_tellus. ".to_string(), 29)
+ );
+ assert_eq!(
+ break_string(20, true, &graphemes[..]),
+ SnippetState::LineEnd("Venenatis_tellus_vel_tellus.".to_string(), 29)
+ );
+ }
+
+ #[test]
+ fn nothing_to_break() {
+ let string = "Venenatis_tellus_vel_tellus";
+ let graphemes = UnicodeSegmentation::graphemes(&*string, false).collect::<Vec<&str>>();
+ assert_eq!(
+ break_string(20, false, &graphemes[..]),
+ SnippetState::EndOfInput("Venenatis_tellus_vel_tellus".to_string())
+ );
+ }
+
+ #[test]
+ fn significant_whitespaces() {
+ let string = "Neque in sem. \n Pellentesque tellus augue.";
+ let graphemes = UnicodeSegmentation::graphemes(&*string, false).collect::<Vec<&str>>();
+ assert_eq!(
+ break_string(15, false, &graphemes[..]),
+ SnippetState::Overflow("Neque in sem. \n".to_string(), 20)
+ );
+ assert_eq!(
+ break_string(25, false, &graphemes[..]),
+ SnippetState::Overflow("Neque in sem. \n".to_string(), 20)
+ );
+ // if `StringFormat::line_end` is true, then the line feed does not matter anymore
+ assert_eq!(
+ break_string(15, true, &graphemes[..]),
+ SnippetState::LineEnd("Neque in sem.".to_string(), 26)
+ );
+ assert_eq!(
+ break_string(25, true, &graphemes[..]),
+ SnippetState::LineEnd("Neque in sem.".to_string(), 26)
+ );
+ }
+
+ #[test]
+ fn big_whitespace() {
+ let string = "Neque in sem. Pellentesque tellus augue.";
+ let graphemes = UnicodeSegmentation::graphemes(&*string, false).collect::<Vec<&str>>();
+ assert_eq!(
+ break_string(20, false, &graphemes[..]),
+ SnippetState::LineEnd("Neque in sem. ".to_string(), 25)
+ );
+ assert_eq!(
+ break_string(20, true, &graphemes[..]),
+ SnippetState::LineEnd("Neque in sem.".to_string(), 25)
+ );
+ }
}
projects / rust.git / blobdiff