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Code Issues Projects Releases Wiki Activity

More utils re-organization

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This commit is contained in:
Alexandre Bury 2018-01-08 12:33:43 +01:00
parent 7ac003c4de
commit c4670e5262
17 changed files with 1059 additions and 1019 deletions
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2
src/printer.rs
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@ -6,7 +6,7 @@ use std::cmp::min;
use std::rc::Rc;
use theme::{BorderStyle, ColorStyle, Effect, Theme};
use unicode_segmentation::UnicodeSegmentation;
use utils::prefix;
use utils::lines::simple::prefix;
use vec::Vec2;
/// Convenient interface to draw on a subset of the screen.

51
src/utils/lines/simple.rs → src/utils/lines/simple/lines_iterator.rs
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@ -1,13 +1,6 @@
//! Compute lines on simple text.
//!
//! The input is a single `&str`.
//!
//! Computed rows will include start/end byte offsets in the input string.
use With;
use unicode_segmentation::UnicodeSegmentation;
use unicode_width::UnicodeWidthStr;
use utils::prefix;
use super::{prefix, Row};
/// Generates rows of text in constrained width.
///
@ -49,41 +42,6 @@ impl<'a> LinesIterator<'a> {
}
}
/// Represents a row of text within a `String`.
///
/// A row is made of offsets into a parent `String`.
/// The corresponding substring should take `width` cells when printed.
#[derive(Debug, Clone, Copy)]
pub struct Row {
/// Beginning of the row in the parent `String`.
pub start: usize,
/// End of the row (excluded)
pub end: usize,
/// Width of the row, in cells.
pub width: usize,
}
impl Row {
/// Shift a row start and end by `offset`.
pub fn shift(&mut self, offset: usize) {
self.start += offset;
self.end += offset;
}
/// Shift a row start and end by `offset`.
///
/// Chainable variant;
pub fn shifted(self, offset: usize) -> Self {
self.with(|s| s.shift(offset))
}
/// Shift back a row start and end by `offset`.
pub fn rev_shift(&mut self, offset: usize) {
self.start -= offset;
self.end -= offset;
}
}
impl<'a> Iterator for LinesIterator<'a> {
type Item = Row;
@ -155,10 +113,3 @@ impl<'a> Iterator for LinesIterator<'a> {
})
}
}
#[cfg(test)]
mod tests {
#[test]
fn test_layout() {}
}

111
src/utils/lines/simple/mod.rs Normal file
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@ -0,0 +1,111 @@
//! Compute lines on simple text.
//!
//! The input is a single `&str`.
//!
//! Computed rows will include start/end byte offsets in the input string.
mod lines_iterator;
mod row;
pub use self::lines_iterator::LinesIterator;
pub use self::row::Row;
use unicode_segmentation::UnicodeSegmentation;
use unicode_width::UnicodeWidthStr;
/// The length and width of a part of a string.
pub struct Span {
/// The length (in bytes) of the string.
pub length: usize,
/// The unicode-width of the string.
pub width: usize,
}
/// Computes a prefix that fits in the given `width`.
///
/// Takes non-breakable elements from `iter`, while keeping the string width
/// under `width` (and adding `delimiter` between each element).
///
/// Given `total_text = iter.collect().join(delimiter)`, the result is the
/// length of the longest prefix of `width` or less cells, without breaking
/// inside an element.
///
/// Example:
///
/// ```
/// # extern crate cursive;
/// extern crate unicode_segmentation;
/// use unicode_segmentation::UnicodeSegmentation;
///
/// # use cursive::utils::prefix;
/// # fn main() {
/// let my_text = "blah...";
/// // This returns the number of bytes for a prefix of `my_text` that
/// // fits within 5 cells.
/// prefix(my_text.graphemes(true), 5, "");
/// # }
/// ```
pub fn prefix<'a, I>(iter: I, available_width: usize, delimiter: &str) -> Span
where
I: Iterator<Item = &'a str>,
{
let delimiter_width = delimiter.width();
let delimiter_len = delimiter.len();
// `current_width` is the width of everything
// before the next token, including any space.
let mut current_width = 0;
let sum: usize = iter.take_while(|token| {
let width = token.width();
if current_width + width > available_width {
false
} else {
// Include the delimiter after this token.
current_width += width;
current_width += delimiter_width;
true
}
}).map(|token| token.len() + delimiter_len)
.sum();
// We counted delimiter once too many times,
// but only if the iterator was non empty.
let length = sum.saturating_sub(delimiter_len);
// `current_width` includes a delimiter after the last token
debug_assert!(current_width <= available_width + delimiter_width);
Span {
length: length,
width: current_width,
}
}
/// Computes the longest suffix that fits in the given `width`.
///
/// Doesn't break inside elements returned by `iter`.
///
/// Returns the number of bytes of the longest
/// suffix from `text` that fits in `width`.
///
/// This is a shortcut for `prefix_length(iter.rev(), width, delimiter)`
pub fn suffix<'a, I>(iter: I, width: usize, delimiter: &str) -> Span
where
I: DoubleEndedIterator<Item = &'a str>,
{
prefix(iter.rev(), width, delimiter)
}
/// Computes the longest suffix that fits in the given `width`.
///
/// Breaks between any two graphemes.
pub fn simple_suffix(text: &str, width: usize) -> Span {
suffix(text.graphemes(true), width, "")
}
/// Computes the longest prefix that fits in the given width.
///
/// Breaks between any two graphemes.
pub fn simple_prefix(text: &str, width: usize) -> Span {
prefix(text.graphemes(true), width, "")
}

37
src/utils/lines/simple/row.rs Normal file
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@ -0,0 +1,37 @@
use With;
/// Represents a row of text within a `String`.
///
/// A row is made of offsets into a parent `String`.
/// The corresponding substring should take `width` cells when printed.
#[derive(Debug, Clone, Copy)]
pub struct Row {
/// Beginning of the row in the parent `String`.
pub start: usize,
/// End of the row (excluded)
pub end: usize,
/// Width of the row, in cells.
pub width: usize,
}
impl Row {
/// Shift a row start and end by `offset`.
pub fn shift(&mut self, offset: usize) {
self.start += offset;
self.end += offset;
}
/// Shift a row start and end by `offset`.
///
/// Chainable variant;
pub fn shifted(self, offset: usize) -> Self {
self.with(|s| s.shift(offset))
}
/// Shift back a row start and end by `offset`.
pub fn rev_shift(&mut self, offset: usize) {
self.start -= offset;
self.end -= offset;
}
}

865
src/utils/lines/spans.rs
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@ -1,865 +0,0 @@
//! Compute lines on multiple spans of text.
//!
//! The input is a list of consecutive text spans.
//!
//! Computed rows will include a list of span segments.
//! Each segment include the source span ID, and start/end byte offsets.
use std::borrow::Cow;
use std::iter::Peekable;
use theme::Style;
use unicode_segmentation::UnicodeSegmentation;
use unicode_width::UnicodeWidthStr;
use xi_unicode::LineBreakLeafIter;
/// Input to the algorithm
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Span<'a> {
text: Cow<'a, str>,
style: Style,
}
/// Refers to a part of a span
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct Segment {
/// ID of the span this segment refers to
pub span_id: usize,
/// Beginning of this segment within the span (included)
pub start: usize,
/// End of this segment within the span (excluded)
pub end: usize,
/// Width of this segment
pub width: usize,
}
impl Segment {
#[cfg(test)]
fn with_text<'a>(self, text: &'a str) -> SegmentWithText<'a> {
SegmentWithText { text, seg: self }
}
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
struct SegmentWithText<'a> {
seg: Segment,
text: &'a str,
}
/// Non-splittable piece of text.
#[derive(Debug, Clone, PartialEq, Eq)]
struct Chunk<'a> {
width: usize,
segments: Vec<SegmentWithText<'a>>,
hard_stop: bool,
ends_with_space: bool,
}
impl<'a> Chunk<'a> {
/// Remove some text from the front.
///
/// We're given the length (number of bytes) and the width.
fn remove_front(&mut self, mut to_remove: ChunkPart) {
// Remove something from each segment until we've removed enough.
for segment in &mut self.segments {
if to_remove.length <= segment.seg.end - segment.seg.start {
// This segment is bigger than what we need to remove
// So just trim the prefix and stop there.
segment.seg.start += to_remove.length;
segment.seg.width -= to_remove.width;
segment.text = &segment.text[to_remove.length..];
break;
} else {
// This segment is too small, so it'll disapear entirely.
to_remove.length -= segment.seg.end - segment.seg.start;
to_remove.width -= segment.seg.width;
// Empty this segment
segment.seg.start = segment.seg.end;
segment.seg.width = 0;
segment.text = &"";
}
}
}
/// Remove the last character from this chunk.
///
/// Usually done to remove a trailing space/newline.
fn remove_last_char(&mut self) {
// We remove the last char in 2 situations:
// * Trailing space.
// * Trailing newline.
// Only in the first case does this affect width.
// (Because newlines have 0 width)
if self.ends_with_space {
// Only reduce the width if the last char was a space.
// Otherwise it's a newline, and we don't want to reduce
// that.
self.width -= 1;
}
// Is the last segment empty after trimming it?
// If yes, just drop it.
let last_empty = {
let last = self.segments.last_mut().unwrap();
last.seg.end -= 1;
if self.ends_with_space {
last.seg.width -= 1;
}
last.seg.start == last.seg.end
};
if last_empty {
self.segments.pop().unwrap();
}
}
}
/// Iterator that returns non-breakable chunks of text.
///
/// Works accross spans of text.
struct ChunkIterator<'a, 'b>
where
'a: 'b,
{
/// Input that we want to split
spans: &'b [Span<'a>],
current_span: usize,
/// How much of the current span has been processed already.
offset: usize,
}
impl<'a, 'b> ChunkIterator<'a, 'b>
where
'a: 'b,
{
fn new(spans: &'b [Span<'a>]) -> Self {
ChunkIterator {
spans,
current_span: 0,
offset: 0,
}
}
}
/// This iterator produces chunks of non-breakable text.
///
/// These chunks may go accross spans (a single word may be broken into more
/// than one span, for instance if parts of it are marked up differently).
impl<'a, 'b> Iterator for ChunkIterator<'a, 'b>
where
'a: 'b,
{
type Item = Chunk<'b>;
fn next(&mut self) -> Option<Self::Item> {
if self.current_span >= self.spans.len() {
return None;
}
let mut span: &Span<'a> = &self.spans[self.current_span];
let mut total_width = 0;
// We'll use an iterator from xi-unicode to detect possible breaks.
let mut iter = LineBreakLeafIter::new(&span.text, self.offset);
// We'll accumulate segments from spans.
let mut segments = Vec::new();
// When we reach the end of a span, xi-unicode returns a break, but it
// actually depends on the next span. Such breaks are "fake" breaks.
// So we'll loop until we find a "true" break
// (a break that doesn't happen an the end of a span).
// Most of the time, it will happen on the first iteration.
loop {
// Look at next possible break
// `hard_stop = true` means that the break is non-optional,
// like after a `\n`.
let (pos, hard_stop) = iter.next(&span.text);
// When xi-unicode reaches the end of a span, it returns a "fake"
// break. To know if it's actually a true break, we need to give
// it the next span. If, given the next span, it returns a break
// at position 0, then the previous one was a true break.
// So when pos = 0, we don't really have a new segment, but we
// can end the current chunk.
let (width, ends_with_space) = if pos == 0 {
// If pos = 0, we had a span before.
let prev_span = &self.spans[self.current_span - 1];
(0, prev_span.text.ends_with(' '))
} else {
// We actually got something.
// Remember its width, and whether it ends with a space.
//
// (When a chunk ends with a space, we may compress it a bit
// near the end of a row, so this information will be useful
// later.)
let text = &span.text[self.offset..pos];
(text.width(), text.ends_with(' '))
};
if pos != 0 {
// If pos != 0, we got an actual segment of a span.
total_width += width;
segments.push(SegmentWithText {
seg: Segment {
span_id: self.current_span,
start: self.offset,
end: pos,
width,
},
text: &span.text[self.offset..pos],
});
}
if pos == span.text.len() {
// If we reached the end of the slice,
// we need to look at the next span first.
self.current_span += 1;
if self.current_span >= self.spans.len() {
// If this was the last chunk, return as is!
return Some(Chunk {
width: total_width,
segments,
hard_stop,
ends_with_space,
});
}
span = &self.spans[self.current_span];
self.offset = 0;
continue;
}
// Remember where we are.
self.offset = pos;
// We found a valid stop, return the current chunk.
return Some(Chunk {
width: total_width,
segments,
hard_stop,
ends_with_space,
});
}
}
}
/// A list of segments representing a row of text
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Row {
/// List of segments
pub segments: Vec<Segment>,
/// Total width for this row
pub width: usize,
}
impl Row {
/// Resolve the row indices into styled spans.
pub fn resolve<'a: 'b, 'b>(&self, spans: &'b [Span<'a>]) -> Vec<Span<'b>> {
self.segments
.iter()
.map(|seg| {
let span: &'b Span<'a> = &spans[seg.span_id];
let text: &'b str = &span.text;
let text: &'b str = &text[seg.start..seg.end];
Span {
text: Cow::Borrowed(text),
style: span.style,
}
})
.collect()
}
}
/// Generates rows of text in constrainted width.
///
/// Works on spans of text.
pub struct SpanLinesIterator<'a, 'b>
where
'a: 'b,
{
iter: Peekable<ChunkIterator<'a, 'b>>,
/// Available width
width: usize,
/// If a chunk wouldn't fit, we had to cut it in pieces.
/// This is how far in the current chunk we are.
chunk_offset: ChunkPart,
}
impl<'a, 'b> SpanLinesIterator<'a, 'b>
where
'a: 'b,
{
/// Creates a new iterator with the given content and width.
pub fn new(spans: &'b [Span<'a>], width: usize) -> Self {
SpanLinesIterator {
iter: ChunkIterator::new(spans).peekable(),
width,
chunk_offset: ChunkPart::default(),
}
}
}
/// Result of a fitness test
///
/// Describes how well a chunk fits in the available space.
enum ChunkFitResult {
/// This chunk can fit as-is
Fits,
/// This chunk fits, but it'll be the last one.
/// Additionally, its last char may need to be removed.
FitsBarely,
/// This chunk doesn't fit. Don't even.
DoesNotFit,
}
/// Look at a chunk, and decide how it could fit.
fn consider_chunk(available: usize, chunk: &Chunk) -> ChunkFitResult {
if chunk.width <= available {
// We fits. No question about it.
if chunk.hard_stop {
// Still, we have to stop here.
// And possibly trim a newline.
ChunkFitResult::FitsBarely
} else {
// Nothing special here.
ChunkFitResult::Fits
}
} else if chunk.width == available + 1 {
// We're just SLIGHTLY too big!
// Can we just pop something?
if chunk.ends_with_space {
// Yay!
ChunkFitResult::FitsBarely
} else {
// Noo(
ChunkFitResult::DoesNotFit
}
} else {
// Can't bargain with me.
ChunkFitResult::DoesNotFit
}
}
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
/// Describes a part of a chunk.
///
/// Includes both length and width to ease some computations.
///
/// This is used to represent how much of a chunk we've already processed.
struct ChunkPart {
width: usize,
length: usize,
}
/// Concatenates chunks as long as they fit in the given width.
fn prefix<'a, I>(
tokens: &mut Peekable<I>, width: usize, offset: &mut ChunkPart
) -> Vec<Chunk<'a>>
where
I: Iterator<Item = Chunk<'a>>,
{
let mut available = width;
let mut chunks = Vec::new();
// Accumulate chunks until it doesn't fit.
loop {
// Look at the next chunk and see if it would fit.
let result = {
let next_chunk = match tokens.peek() {
None => break,
Some(chunk) => chunk,
};
// When considering if the chunk fits, remember that we may
// already have processed part of it.
// So (chunk - width) fits available
// if chunks fits (available + width)
consider_chunk(available + offset.width, next_chunk)
};
match result {
ChunkFitResult::Fits => {
// It fits! Add it and move to the next one.
let mut chunk = tokens.next().unwrap();
// Remember to strip the prefix, in case we took some earlier.
chunk.remove_front(*offset);
// And reset out offset.
offset.length = 0;
offset.width = 0;
available -= chunk.width;
chunks.push(chunk);
continue;
}
ChunkFitResult::FitsBarely => {
// That's it, it's the last one and we're off.
let mut chunk = tokens.next().unwrap();
chunk.remove_front(*offset);
offset.length = 0;
offset.width = 0;
// We know we need to remove the last character.
// Because it's either:
// * A hard stop: there is a newline
// * A compressed chunk: it ends with a space
chunk.remove_last_char();
chunks.push(chunk);
// No need to update `available`,
// as we're ending the line anyway.
break;
}
ChunkFitResult::DoesNotFit => {
break;
}
}
}
chunks
}
impl<'a, 'b> Iterator for SpanLinesIterator<'a, 'b>
where
'a: 'b,
{
type Item = Row;
fn next(&mut self) -> Option<Row> {
// Let's build a beautiful row.
let mut chunks =
prefix(&mut self.iter, self.width, &mut self.chunk_offset);
if chunks.is_empty() {
// Desperate action to make something fit:
// Look at the current chunk. We'll try to return a part of it.
// So now, consider each individual grapheme as a valid chunk.
// Note: it may not be the first time we try to fit this chunk,
// so remember to trim the offset we may have stored.
match self.iter.peek() {
None => return None,
Some(chunk) => {
let mut chunk = chunk.clone();
chunk.remove_front(self.chunk_offset);
// Try to fit part of it?
let graphemes = chunk.segments.iter().flat_map(|seg| {
let mut offset = seg.seg.start;
seg.text.graphemes(true).map(move |g| {
let width = g.width();
let start = offset;
let end = offset + g.len();
offset = end;
Chunk {
width,
segments: vec![
SegmentWithText {
text: g,
seg: Segment {
width,
span_id: seg.seg.span_id,
start,
end,
},
},
],
hard_stop: false,
ends_with_space: false,
}
})
});
chunks = prefix(
&mut graphemes.peekable(),
self.width,
&mut ChunkPart::default(),
);
if chunks.is_empty() {
// Seriously? After everything we did for you?
return None;
}
// We are going to return a part of a chunk.
// So remember what we selected,
// so we can skip it next time.
let width: usize =
chunks.iter().map(|chunk| chunk.width).sum();
let length: usize = chunks
.iter()
.flat_map(|chunk| chunk.segments.iter())
.map(|segment| segment.text.len())
.sum();
self.chunk_offset.width += width;
self.chunk_offset.length += length;
}
}
}
let width = chunks.iter().map(|c| c.width).sum();
assert!(width <= self.width);
// Concatenate all segments
let segments = SegmentMergeIterator::new(
chunks
.into_iter()
.flat_map(|chunk| chunk.segments)
.map(|segment| segment.seg)
.filter(|segment| segment.start != segment.end),
).collect();
// TODO: merge consecutive segments of the same span
Some(Row { segments, width })
}
}
struct SegmentMergeIterator<I> {
current: Option<Segment>,
inner: I,
}
impl<I> SegmentMergeIterator<I> {
fn new(inner: I) -> Self {
SegmentMergeIterator {
inner,
current: None,
}
}
}
impl<I> Iterator for SegmentMergeIterator<I>
where
I: Iterator<Item = Segment>,
{
type Item = Segment;
fn next(&mut self) -> Option<Self::Item> {
if self.current.is_none() {
self.current = self.inner.next();
if self.current.is_none() {
return None;
}
}
loop {
match self.inner.next() {
None => return self.current.take(),
Some(next) => {
if next.span_id == self.current.unwrap().span_id {
let current = self.current.as_mut().unwrap();
current.end = next.end;
current.width += next.width;
} else {
let current = self.current.take();
self.current = Some(next);
return current;
}
}
}
}
}
}
#[cfg(test)]
mod tests {
use super::*;
fn input() -> Vec<Span<'static>> {
vec![
Span {
text: Cow::Borrowed("A beautiful "),
style: Style::none(),
},
Span {
text: Cow::Borrowed("boat"),
style: Style::none(),
},
Span {
text: Cow::Borrowed(" isn't it?\nYes indeed, my "),
style: Style::none(),
},
Span {
text: Cow::Borrowed("Super"),
style: Style::none(),
},
Span {
text: Cow::Borrowed("Captain !"),
style: Style::none(),
},
]
}
#[test]
fn test_lines_iter() {
let input = input();
let iter = SpanLinesIterator::new(&input, 16);
let rows: Vec<Row> = iter.collect();
let spans: Vec<_> =
rows.iter().map(|row| row.resolve(&input)).collect();
assert_eq!(
&spans[..],
&[
vec![
Span {
text: Cow::Borrowed("A beautiful "),
style: Style::none(),
},
Span {
text: Cow::Borrowed("boat"),
style: Style::none(),
}
],
vec![
Span {
text: Cow::Borrowed("isn\'t it?"),
style: Style::none(),
}
],
vec![
Span {
text: Cow::Borrowed("Yes indeed, my "),
style: Style::none(),
}
],
vec![
Span {
text: Cow::Borrowed("Super"),
style: Style::none(),
},
Span {
text: Cow::Borrowed("Captain !"),
style: Style::none(),
}
]
]
);
assert_eq!(
&rows[..],
&[
Row {
segments: vec![
Segment {
span_id: 0,
start: 0,
end: 12,
width: 12,
},
Segment {
span_id: 1,
start: 0,
end: 4,
width: 4,
},
],
width: 16,
},
Row {
segments: vec![
Segment {
span_id: 2,
start: 1,
end: 10,
width: 9,
},
],
width: 9,
},
Row {
segments: vec![
Segment {
span_id: 2,
start: 11,
end: 26,
width: 15,
},
],
width: 15,
},
Row {
segments: vec![
Segment {
span_id: 3,
start: 0,
end: 5,
width: 5,
},
Segment {
span_id: 4,
start: 0,
end: 9,
width: 9,
},
],
width: 14,
}
]
);
}
#[test]
fn test_chunk_iter() {
let input = input();
let iter = ChunkIterator::new(&input);
let chunks: Vec<Chunk> = iter.collect();
assert_eq!(
&chunks[..],
&[
Chunk {
width: 2,
segments: vec![
Segment {
span_id: 0,
start: 0,
end: 2,
width: 2,
}.with_text("A "),
],
hard_stop: false,
ends_with_space: true,
},
Chunk {
width: 10,
segments: vec![
Segment {
span_id: 0,
start: 2,
end: 12,
width: 10,
}.with_text("beautiful "),
],
hard_stop: false,
ends_with_space: true,
},
Chunk {
width: 5,
segments: vec![
Segment {
span_id: 1,
start: 0,
end: 4,
width: 4,
}.with_text("boat"),
Segment {
span_id: 2,
start: 0,
end: 1,
width: 1,
}.with_text(" "),
],
hard_stop: false,
ends_with_space: true,
},
Chunk {
width: 6,
segments: vec![
// "isn't "
Segment {
span_id: 2,
start: 1,
end: 7,
width: 6,
}.with_text("isn't "),
],
hard_stop: false,
ends_with_space: true,
},
Chunk {
width: 3,
segments: vec![
// "it?\n"
Segment {
span_id: 2,
start: 7,
end: 11,
width: 3,
}.with_text("it?\n"),
],
hard_stop: true,
ends_with_space: false,
},
Chunk {
width: 4,
segments: vec![
// "Yes "
Segment {
span_id: 2,
start: 11,
end: 15,
width: 4,
}.with_text("Yes "),
],
hard_stop: false,
ends_with_space: true,
},
Chunk {
width: 8,
segments: vec![
// "indeed, "
Segment {
span_id: 2,
start: 15,
end: 23,
width: 8,
}.with_text("indeed, "),
],
hard_stop: false,
ends_with_space: true,
},
Chunk {
width: 3,
segments: vec![
// "my "
Segment {
span_id: 2,
start: 23,
end: 26,
width: 3,
}.with_text("my "),
],
hard_stop: false,
ends_with_space: true,
},
Chunk {
width: 14,
segments: vec![
// "Super"
Segment {
span_id: 3,
start: 0,
end: 5,
width: 5,
}.with_text("Super"),
// "Captain !"
Segment {
span_id: 4,
start: 0,
end: 9,
width: 9,
}.with_text("Captain !"),
],
hard_stop: false,
ends_with_space: false,
}
]
);
}
}

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use super::segment::SegmentWithText;
/// Non-splittable piece of text.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Chunk<'a> {
pub width: usize,
pub segments: Vec<SegmentWithText<'a>>,
pub hard_stop: bool,
pub ends_with_space: bool,
}
impl<'a> Chunk<'a> {
/// Remove some text from the front.
///
/// We're given the length (number of bytes) and the width.
pub fn remove_front(&mut self, mut to_remove: ChunkPart) {
// Remove something from each segment until we've removed enough.
for segment in &mut self.segments {
if to_remove.length <= segment.seg.end - segment.seg.start {
// This segment is bigger than what we need to remove
// So just trim the prefix and stop there.
segment.seg.start += to_remove.length;
segment.seg.width -= to_remove.width;
segment.text = &segment.text[to_remove.length..];
break;
} else {
// This segment is too small, so it'll disapear entirely.
to_remove.length -= segment.seg.end - segment.seg.start;
to_remove.width -= segment.seg.width;
// Empty this segment
segment.seg.start = segment.seg.end;
segment.seg.width = 0;
segment.text = &"";
}
}
}
/// Remove the last character from this chunk.
///
/// Usually done to remove a trailing space/newline.
pub fn remove_last_char(&mut self) {
// We remove the last char in 2 situations:
// * Trailing space.
// * Trailing newline.
// Only in the first case does this affect width.
// (Because newlines have 0 width)
if self.ends_with_space {
// Only reduce the width if the last char was a space.
// Otherwise it's a newline, and we don't want to reduce
// that.
self.width -= 1;
}
// Is the last segment empty after trimming it?
// If yes, just drop it.
let last_empty = {
let last = self.segments.last_mut().unwrap();
last.seg.end -= 1;
if self.ends_with_space {
last.seg.width -= 1;
}
last.seg.start == last.seg.end
};
if last_empty {
self.segments.pop().unwrap();
}
}
}
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
/// Describes a part of a chunk.
///
/// Includes both length and width to ease some computations.
///
/// This is used to represent how much of a chunk we've already processed.
pub struct ChunkPart {
pub width: usize,
pub length: usize,
}

141
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use super::Span;
use super::chunk::Chunk;
use super::segment::{Segment, SegmentWithText};
use unicode_width::UnicodeWidthStr;
use xi_unicode::LineBreakLeafIter;
/// Iterator that returns non-breakable chunks of text.
///
/// Works accross spans of text.
pub struct ChunkIterator<'a, 'b>
where
'a: 'b,
{
/// Input that we want to split
spans: &'b [Span<'a>],
current_span: usize,
/// How much of the current span has been processed already.
offset: usize,
}
impl<'a, 'b> ChunkIterator<'a, 'b>
where
'a: 'b,
{
pub fn new(spans: &'b [Span<'a>]) -> Self {
ChunkIterator {
spans,
current_span: 0,
offset: 0,
}
}
}
/// This iterator produces chunks of non-breakable text.
///
/// These chunks may go accross spans (a single word may be broken into more
/// than one span, for instance if parts of it are marked up differently).
impl<'a, 'b> Iterator for ChunkIterator<'a, 'b>
where
'a: 'b,
{
type Item = Chunk<'b>;
fn next(&mut self) -> Option<Self::Item> {
if self.current_span >= self.spans.len() {
return None;
}
let mut span: &Span<'a> = &self.spans[self.current_span];
let mut total_width = 0;
// We'll use an iterator from xi-unicode to detect possible breaks.
let mut iter = LineBreakLeafIter::new(&span.text, self.offset);
// We'll accumulate segments from spans.
let mut segments = Vec::new();
// When we reach the end of a span, xi-unicode returns a break, but it
// actually depends on the next span. Such breaks are "fake" breaks.
// So we'll loop until we find a "true" break
// (a break that doesn't happen an the end of a span).
// Most of the time, it will happen on the first iteration.
loop {
// Look at next possible break
// `hard_stop = true` means that the break is non-optional,
// like after a `\n`.
let (pos, hard_stop) = iter.next(&span.text);
// When xi-unicode reaches the end of a span, it returns a "fake"
// break. To know if it's actually a true break, we need to give
// it the next span. If, given the next span, it returns a break
// at position 0, then the previous one was a true break.
// So when pos = 0, we don't really have a new segment, but we
// can end the current chunk.
let (width, ends_with_space) = if pos == 0 {
// If pos = 0, we had a span before.
let prev_span = &self.spans[self.current_span - 1];
(0, prev_span.text.ends_with(' '))
} else {
// We actually got something.
// Remember its width, and whether it ends with a space.
//
// (When a chunk ends with a space, we may compress it a bit
// near the end of a row, so this information will be useful
// later.)
let text = &span.text[self.offset..pos];
(text.width(), text.ends_with(' '))
};
if pos != 0 {
// If pos != 0, we got an actual segment of a span.
total_width += width;
segments.push(SegmentWithText {
seg: Segment {
span_id: self.current_span,
start: self.offset,
end: pos,
width,
},
text: &span.text[self.offset..pos],
});
}
if pos == span.text.len() {
// If we reached the end of the slice,
// we need to look at the next span first.
self.current_span += 1;
if self.current_span >= self.spans.len() {
// If this was the last chunk, return as is!
return Some(Chunk {
width: total_width,
segments,
hard_stop,
ends_with_space,
});
}
span = &self.spans[self.current_span];
self.offset = 0;
continue;
}
// Remember where we are.
self.offset = pos;
// We found a valid stop, return the current chunk.
return Some(Chunk {
width: total_width,
segments,
hard_stop,
ends_with_space,
});
}
}
}

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use super::Span;
use super::chunk::{Chunk, ChunkPart};
use super::chunk_iterator::ChunkIterator;
use super::prefix::prefix;
use super::row::Row;
use super::segment::{Segment, SegmentWithText};
use super::segment_merge_iterator::SegmentMergeIterator;
use std::iter::Peekable;
use unicode_segmentation::UnicodeSegmentation;
use unicode_width::UnicodeWidthStr;
/// Generates rows of text in constrainted width.
///
/// Works on spans of text.
pub struct SpanLinesIterator<'a, 'b>
where
'a: 'b,
{
iter: Peekable<ChunkIterator<'a, 'b>>,
/// Available width
width: usize,
/// If a chunk wouldn't fit, we had to cut it in pieces.
/// This is how far in the current chunk we are.
chunk_offset: ChunkPart,
}
impl<'a, 'b> SpanLinesIterator<'a, 'b>
where
'a: 'b,
{
/// Creates a new iterator with the given content and width.
pub fn new(spans: &'b [Span<'a>], width: usize) -> Self {
SpanLinesIterator {
iter: ChunkIterator::new(spans).peekable(),
width,
chunk_offset: ChunkPart::default(),
}
}
}
impl<'a, 'b> Iterator for SpanLinesIterator<'a, 'b>
where
'a: 'b,
{
type Item = Row;
fn next(&mut self) -> Option<Row> {
// Let's build a beautiful row.
let mut chunks =
prefix(&mut self.iter, self.width, &mut self.chunk_offset);
if chunks.is_empty() {
// Desperate action to make something fit:
// Look at the current chunk. We'll try to return a part of it.
// So now, consider each individual grapheme as a valid chunk.
// Note: it may not be the first time we try to fit this chunk,
// so remember to trim the offset we may have stored.
match self.iter.peek() {
None => return None,
Some(chunk) => {
let mut chunk = chunk.clone();
chunk.remove_front(self.chunk_offset);
// Try to fit part of it?
let graphemes = chunk.segments.iter().flat_map(|seg| {
let mut offset = seg.seg.start;
seg.text.graphemes(true).map(move |g| {
let width = g.width();
let start = offset;
let end = offset + g.len();
offset = end;
Chunk {
width,
segments: vec![
SegmentWithText {
text: g,
seg: Segment {
width,
span_id: seg.seg.span_id,
start,
end,
},
},
],
hard_stop: false,
ends_with_space: false,
}
})
});
chunks = prefix(
&mut graphemes.peekable(),
self.width,
&mut ChunkPart::default(),
);
if chunks.is_empty() {
// Seriously? After everything we did for you?
return None;
}
// We are going to return a part of a chunk.
// So remember what we selected,
// so we can skip it next time.
let width: usize =
chunks.iter().map(|chunk| chunk.width).sum();
let length: usize = chunks
.iter()
.flat_map(|chunk| chunk.segments.iter())
.map(|segment| segment.text.len())
.sum();
self.chunk_offset.width += width;
self.chunk_offset.length += length;
}
}
}
let width = chunks.iter().map(|c| c.width).sum();
assert!(width <= self.width);
// Concatenate all segments
let segments = SegmentMergeIterator::new(
chunks
.into_iter()
.flat_map(|chunk| chunk.segments)
.map(|segment| segment.seg)
.filter(|segment| segment.start != segment.end),
).collect();
// TODO: merge consecutive segments of the same span
Some(Row { segments, width })
}
}

40
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//! Compute lines on multiple spans of text.
//!
//! The input is a list of consecutive text spans.
//!
//! Computed rows will include a list of span segments.
//! Each segment include the source span ID, and start/end byte offsets.
mod lines_iterator;
mod chunk_iterator;
mod segment_merge_iterator;
mod row;
mod prefix;
mod chunk;
mod segment;
#[cfg(test)]
mod tests;
use std::borrow::Cow;
use theme::Style;
pub use self::lines_iterator::SpanLinesIterator;
pub use self::row::Row;
pub use self::segment::Segment;
/// Input to the algorithm
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Span<'a> {
/// Text for this span.
///
/// It can be either a reference to some input text,
/// or an owned string.
///
/// The owned string is mostly useful when parsing marked-up text that
/// contains escape codes.
pub text: Cow<'a, str>,
/// Style to apply to this span of text.
pub style: Style,
}

112
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use super::chunk::{Chunk, ChunkPart};
use std::iter::Peekable;
/// Concatenates chunks as long as they fit in the given width.
pub fn prefix<'a, I>(
tokens: &mut Peekable<I>, width: usize, offset: &mut ChunkPart
) -> Vec<Chunk<'a>>
where
I: Iterator<Item = Chunk<'a>>,
{
let mut available = width;
let mut chunks = Vec::new();
// Accumulate chunks until it doesn't fit.
loop {
// Look at the next chunk and see if it would fit.
let result = {
let next_chunk = match tokens.peek() {
None => break,
Some(chunk) => chunk,
};
// When considering if the chunk fits, remember that we may
// already have processed part of it.
// So (chunk - width) fits available
// if chunks fits (available + width)
consider_chunk(available + offset.width, next_chunk)
};
match result {
ChunkFitResult::Fits => {
// It fits! Add it and move to the next one.
let mut chunk = tokens.next().unwrap();
// Remember to strip the prefix, in case we took some earlier.
chunk.remove_front(*offset);
// And reset out offset.
offset.length = 0;
offset.width = 0;
available -= chunk.width;
chunks.push(chunk);
continue;
}
ChunkFitResult::FitsBarely => {
// That's it, it's the last one and we're off.
let mut chunk = tokens.next().unwrap();
chunk.remove_front(*offset);
offset.length = 0;
offset.width = 0;
// We know we need to remove the last character.
// Because it's either:
// * A hard stop: there is a newline
// * A compressed chunk: it ends with a space
chunk.remove_last_char();
chunks.push(chunk);
// No need to update `available`,
// as we're ending the line anyway.
break;
}
ChunkFitResult::DoesNotFit => {
break;
}
}
}
chunks
}
/// Result of a fitness test
///
/// Describes how well a chunk fits in the available space.
enum ChunkFitResult {
/// This chunk can fit as-is
Fits,
/// This chunk fits, but it'll be the last one.
/// Additionally, its last char may need to be removed.
FitsBarely,
/// This chunk doesn't fit. Don't even.
DoesNotFit,
}
/// Look at a chunk, and decide how it could fit.
fn consider_chunk(available: usize, chunk: &Chunk) -> ChunkFitResult {
if chunk.width <= available {
// We fits. No question about it.
if chunk.hard_stop {
// Still, we have to stop here.
// And possibly trim a newline.
ChunkFitResult::FitsBarely
} else {
// Nothing special here.
ChunkFitResult::Fits
}
} else if chunk.width == available + 1 {
// We're just SLIGHTLY too big!
// Can we just pop something?
if chunk.ends_with_space {
// Yay!
ChunkFitResult::FitsBarely
} else {
// Noo(
ChunkFitResult::DoesNotFit
}
} else {
// Can't bargain with me.
ChunkFitResult::DoesNotFit
}
}

33
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use std::borrow::Cow;
use super::{Span, Segment};
/// A list of segments representing a row of text
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Row {
/// List of segments
pub segments: Vec<Segment>,
/// Total width for this row
pub width: usize,
}
impl Row {
/// Resolve the row indices into styled spans.
pub fn resolve<'a: 'b, 'b>(&self, spans: &'b [Span<'a>]) -> Vec<Span<'b>> {
self.segments
.iter()
.map(|seg| {
let span: &'b Span<'a> = &spans[seg.span_id];
let text: &'b str = &span.text;
let text: &'b str = &text[seg.start..seg.end];
Span {
text: Cow::Borrowed(text),
style: span.style,
}
})
.collect()
}
}

28
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/// Refers to a part of a span
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct Segment {
/// ID of the span this segment refers to
pub span_id: usize,
/// Beginning of this segment within the span (included)
pub start: usize,
/// End of this segment within the span (excluded)
pub end: usize,
/// Width of this segment
pub width: usize,
}
impl Segment {
#[cfg(test)]
fn with_text<'a>(self, text: &'a str) -> SegmentWithText<'a> {
SegmentWithText { text, seg: self }
}
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct SegmentWithText<'a> {
pub seg: Segment,
pub text: &'a str,
}

50
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use super::Segment;
pub struct SegmentMergeIterator<I> {
current: Option<Segment>,
inner: I,
}
impl<I> SegmentMergeIterator<I> {
pub fn new(inner: I) -> Self {
SegmentMergeIterator {
inner,
current: None,
}
}
}
impl<I> Iterator for SegmentMergeIterator<I>
where
I: Iterator<Item = Segment>,
{
type Item = Segment;
fn next(&mut self) -> Option<Self::Item> {
if self.current.is_none() {
self.current = self.inner.next();
if self.current.is_none() {
return None;
}
}
loop {
match self.inner.next() {
None => return self.current.take(),
Some(next) => {
if next.span_id == self.current.unwrap().span_id {
let current = self.current.as_mut().unwrap();
current.end = next.end;
current.width += next.width;
} else {
let current = self.current.take();
self.current = Some(next);
return current;
}
}
}
}
}
}

285
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use super::*;
fn input() -> Vec<Span<'static>> {
vec![
Span {
text: Cow::Borrowed("A beautiful "),
style: Style::none(),
},
Span {
text: Cow::Borrowed("boat"),
style: Style::none(),
},
Span {
text: Cow::Borrowed(" isn't it?\nYes indeed, my "),
style: Style::none(),
},
Span {
text: Cow::Borrowed("Super"),
style: Style::none(),
},
Span {
text: Cow::Borrowed("Captain !"),
style: Style::none(),
},
]
}
#[test]
fn test_lines_iter() {
let input = input();
let iter = SpanLinesIterator::new(&input, 16);
let rows: Vec<Row> = iter.collect();
let spans: Vec<_> = rows.iter().map(|row| row.resolve(&input)).collect();
assert_eq!(
&spans[..],
&[
vec![
Span {
text: Cow::Borrowed("A beautiful "),
style: Style::none(),
},
Span {
text: Cow::Borrowed("boat"),
style: Style::none(),
},
],
vec![
Span {
text: Cow::Borrowed("isn\'t it?"),
style: Style::none(),
},
],
vec![
Span {
text: Cow::Borrowed("Yes indeed, my "),
style: Style::none(),
},
],
vec![
Span {
text: Cow::Borrowed("Super"),
style: Style::none(),
},
Span {
text: Cow::Borrowed("Captain !"),
style: Style::none(),
},
]
]
);
assert_eq!(
&rows[..],
&[
Row {
segments: vec![
Segment {
span_id: 0,
start: 0,
end: 12,
width: 12,
},
Segment {
span_id: 1,
start: 0,
end: 4,
width: 4,
},
],
width: 16,
},
Row {
segments: vec![
Segment {
span_id: 2,
start: 1,
end: 10,
width: 9,
},
],
width: 9,
},
Row {
segments: vec![
Segment {
span_id: 2,
start: 11,
end: 26,
width: 15,
},
],
width: 15,
},
Row {
segments: vec![
Segment {
span_id: 3,
start: 0,
end: 5,
width: 5,
},
Segment {
span_id: 4,
start: 0,
end: 9,
width: 9,
},
],
width: 14,
}
]
);
}
#[test]
fn test_chunk_iter() {
let input = input();
let iter = ChunkIterator::new(&input);
let chunks: Vec<Chunk> = iter.collect();
assert_eq!(
&chunks[..],
&[
Chunk {
width: 2,
segments: vec![
Segment {
span_id: 0,
start: 0,
end: 2,
width: 2,
}.with_text("A "),
],
hard_stop: false,
ends_with_space: true,
},
Chunk {
width: 10,
segments: vec![
Segment {
span_id: 0,
start: 2,
end: 12,
width: 10,
}.with_text("beautiful "),
],
hard_stop: false,
ends_with_space: true,
},
Chunk {
width: 5,
segments: vec![
Segment {
span_id: 1,
start: 0,
end: 4,
width: 4,
}.with_text("boat"),
Segment {
span_id: 2,
start: 0,
end: 1,
width: 1,
}.with_text(" "),
],
hard_stop: false,
ends_with_space: true,
},
Chunk {
width: 6,
segments: vec![
// "isn't "
Segment {
span_id: 2,
start: 1,
end: 7,
width: 6,
}.with_text("isn't "),
],
hard_stop: false,
ends_with_space: true,
},
Chunk {
width: 3,
segments: vec![
// "it?\n"
Segment {
span_id: 2,
start: 7,
end: 11,
width: 3,
}.with_text("it?\n"),
],
hard_stop: true,
ends_with_space: false,
},
Chunk {
width: 4,
segments: vec![
// "Yes "
Segment {
span_id: 2,
start: 11,
end: 15,
width: 4,
}.with_text("Yes "),
],
hard_stop: false,
ends_with_space: true,
},
Chunk {
width: 8,
segments: vec![
// "indeed, "
Segment {
span_id: 2,
start: 15,
end: 23,
width: 8,
}.with_text("indeed, "),
],
hard_stop: false,
ends_with_space: true,
},
Chunk {
width: 3,
segments: vec![
// "my "
Segment {
span_id: 2,
start: 23,
end: 26,
width: 3,
}.with_text("my "),
],
hard_stop: false,
ends_with_space: true,
},
Chunk {
width: 14,
segments: vec![
// "Super"
Segment {
span_id: 3,
start: 0,
end: 5,
width: 5,
}.with_text("Super"),
// "Captain !"
Segment {
span_id: 4,
start: 0,
end: 9,
width: 9,
}.with_text("Captain !"),
],
hard_stop: false,
ends_with_space: false,
}
]
);
}

100
src/utils/mod.rs
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@ -1,110 +1,10 @@
//! Toolbox to make text layout easier.
use unicode_segmentation::UnicodeSegmentation;
use unicode_width::UnicodeWidthStr;
mod reader;
pub mod lines;
pub use self::reader::ProgressReader;
/// The length and width of a part of a string.
pub struct Span {
/// The length (in bytes) of the string.
pub length: usize,
/// The unicode-width of the string.
pub width: usize,
}
/// Computes a prefix that fits in the given `width`.
///
/// Takes non-breakable elements from `iter`, while keeping the string width
/// under `width` (and adding `delimiter` between each element).
///
/// Given `total_text = iter.collect().join(delimiter)`, the result is the
/// length of the longest prefix of `width` or less cells, without breaking
/// inside an element.
///
/// Example:
///
/// ```
/// # extern crate cursive;
/// extern crate unicode_segmentation;
/// use unicode_segmentation::UnicodeSegmentation;
///
/// # use cursive::utils::prefix;
/// # fn main() {
/// let my_text = "blah...";
/// // This returns the number of bytes for a prefix of `my_text` that
/// // fits within 5 cells.
/// prefix(my_text.graphemes(true), 5, "");
/// # }
/// ```
pub fn prefix<'a, I>(iter: I, available_width: usize, delimiter: &str) -> Span
where
I: Iterator<Item = &'a str>,
{
let delimiter_width = delimiter.width();
let delimiter_len = delimiter.len();
// `current_width` is the width of everything
// before the next token, including any space.
let mut current_width = 0;
let sum: usize = iter.take_while(|token| {
let width = token.width();
if current_width + width > available_width {
false
} else {
// Include the delimiter after this token.
current_width += width;
current_width += delimiter_width;
true
}
}).map(|token| token.len() + delimiter_len)
.sum();
// We counted delimiter once too many times,
// but only if the iterator was non empty.
let length = sum.saturating_sub(delimiter_len);
// `current_width` includes a delimiter after the last token
debug_assert!(current_width <= available_width + delimiter_width);
Span {
length: length,
width: current_width,
}
}
/// Computes the longest suffix that fits in the given `width`.
///
/// Doesn't break inside elements returned by `iter`.
///
/// Returns the number of bytes of the longest
/// suffix from `text` that fits in `width`.
///
/// This is a shortcut for `prefix_length(iter.rev(), width, delimiter)`
pub fn suffix<'a, I>(iter: I, width: usize, delimiter: &str) -> Span
where
I: DoubleEndedIterator<Item = &'a str>,
{
prefix(iter.rev(), width, delimiter)
}
/// Computes the longest suffix that fits in the given `width`.
///
/// Breaks between any two graphemes.
pub fn simple_suffix(text: &str, width: usize) -> Span {
suffix(text.graphemes(true), width, "")
}
/// Computes the longest prefix that fits in the given width.
///
/// Breaks between any two graphemes.
pub fn simple_prefix(text: &str, width: usize) -> Span {
prefix(text.graphemes(true), width, "")
}
#[cfg(test)]
mod tests {
use utils;

2
src/views/edit_view.rs
View File

@ -6,7 +6,7 @@ use std::rc::Rc;
use theme::{ColorStyle, Effect};
use unicode_segmentation::UnicodeSegmentation;
use unicode_width::UnicodeWidthStr;
use utils::{simple_prefix, simple_suffix};
use utils::lines::simple::{simple_prefix, simple_suffix};
use vec::Vec2;
use view::View;

3
src/views/text_area.rs
View File

@ -5,8 +5,7 @@ use std::cmp::min;
use theme::{ColorStyle, Effect};
use unicode_segmentation::UnicodeSegmentation;
use unicode_width::UnicodeWidthStr;
use utils::{prefix, simple_prefix};
use utils::lines::simple::{LinesIterator, Row};
use utils::lines::simple::{prefix, simple_prefix, LinesIterator, Row};
use vec::Vec2;
use view::{ScrollBase, SizeCache, View};