Determine whether to use a margin of 0 or 1 when uncommenting (#476)

* Implement `margin` calculation for uncommenting

* Move `margin` calculation to `find_line_comment`

* Fix comment bug with multiple selections on a line

* Fix `find_line_comment` test for new return type

* Generate a single vec of lines for comment toggle

`toggle_line_comments` collects the lines covered by all selections into
a `Vec`, skipping duplicates. `find_line_comment` now returns the lines
to operate on, instead of returning the lines to skip.

* Fix test for `find_line_comment`

* Reserve length of `to_change` instead of `lines`

The length of `lines` includes blank lines which will be skipped, and as
such do not need space for a change reserved for them. `to_change`
includes only the lines which will be changed.

* Use `token.chars().count()` for token char length

* Create `changes` with capacity instead of reserving

* Remove unnecessary clones in `test_find_line_comment`

* Add test case for 0 margin comments

* Add comments explaining `find_line_comment`
This commit is contained in:
Omnikar 2021-07-25 22:00:58 -04:00 committed by GitHub
parent e07e42dcfb
commit 112ae5cffe
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@ -1,17 +1,27 @@
use crate::{
find_first_non_whitespace_char, Change, Rope, RopeSlice, Selection, Tendril, Transaction,
};
use core::ops::Range;
use std::borrow::Cow;
/// Given text, a comment token, and a set of line indices, returns the following:
/// - Whether the given lines should be considered commented
/// - If any of the lines are uncommented, all lines are considered as such.
/// - The lines to change for toggling comments
/// - This is all provided lines excluding blanks lines.
/// - The column of the comment tokens
/// - Column of existing tokens, if the lines are commented; column to place tokens at otherwise.
/// - The margin to the right of the comment tokens
/// - Defaults to `1`. If any existing comment token is not followed by a space, changes to `0`.
fn find_line_comment(
token: &str,
text: RopeSlice,
lines: Range<usize>,
) -> (bool, Vec<usize>, usize) {
lines: impl IntoIterator<Item = usize>,
) -> (bool, Vec<usize>, usize, usize) {
let mut commented = true;
let mut skipped = Vec::new();
let mut to_change = Vec::new();
let mut min = usize::MAX; // minimum col for find_first_non_whitespace_char
let mut margin = 1;
let token_len = token.chars().count();
for line in lines {
let line_slice = text.line(line);
if let Some(pos) = find_first_non_whitespace_char(line_slice) {
@ -29,47 +39,53 @@ fn find_line_comment(
// considered uncommented.
commented = false;
}
} else {
// blank line
skipped.push(line);
// determine margin of 0 or 1 for uncommenting; if any comment token is not followed by a space,
// a margin of 0 is used for all lines.
if matches!(line_slice.get_char(pos + token_len), Some(c) if c != ' ') {
margin = 0;
}
// blank lines don't get pushed.
to_change.push(line);
}
}
(commented, skipped, min)
(commented, to_change, min, margin)
}
#[must_use]
pub fn toggle_line_comments(doc: &Rope, selection: &Selection, token: Option<&str>) -> Transaction {
let text = doc.slice(..);
let mut changes: Vec<Change> = Vec::new();
let token = token.unwrap_or("//");
let comment = Tendril::from(format!("{} ", token));
let mut lines: Vec<usize> = Vec::new();
let mut min_next_line = 0;
for selection in selection {
let start = text.char_to_line(selection.from());
let end = text.char_to_line(selection.to());
let lines = start..end + 1;
let (commented, skipped, min) = find_line_comment(&token, text, lines.clone());
let start = text.char_to_line(selection.from()).max(min_next_line);
let end = text.char_to_line(selection.to()) + 1;
lines.extend(start..end);
min_next_line = end + 1;
}
changes.reserve((end - start).saturating_sub(skipped.len()));
let (commented, to_change, min, margin) = find_line_comment(&token, text, lines);
for line in lines {
if skipped.contains(&line) {
continue;
}
let mut changes: Vec<Change> = Vec::with_capacity(to_change.len());
let pos = text.line_to_char(line) + min;
for line in to_change {
let pos = text.line_to_char(line) + min;
if !commented {
// comment line
changes.push((pos, pos, Some(comment.clone())))
} else {
// uncomment line
let margin = 1; // TODO: margin is hardcoded 1 but could easily be 0
changes.push((pos, pos + token.len() + margin, None))
}
if !commented {
// comment line
changes.push((pos, pos, Some(comment.clone())));
} else {
// uncomment line
changes.push((pos, pos + token.len() + margin, None));
}
}
Transaction::change(doc, changes.into_iter())
}
@ -91,23 +107,32 @@ mod test {
let text = state.doc.slice(..);
let res = find_line_comment("//", text, 0..3);
// (commented = true, skipped = [line 1], min = col 2)
assert_eq!(res, (false, vec![1], 2));
// (commented = true, to_change = [line 0, line 2], min = col 2, margin = 1)
assert_eq!(res, (false, vec![0, 2], 2, 1));
// comment
let transaction = toggle_line_comments(&state.doc, &state.selection, None);
transaction.apply(&mut state.doc);
state.selection = state.selection.clone().map(transaction.changes());
state.selection = state.selection.map(transaction.changes());
assert_eq!(state.doc, " // 1\n\n // 2\n // 3");
// uncomment
let transaction = toggle_line_comments(&state.doc, &state.selection, None);
transaction.apply(&mut state.doc);
state.selection = state.selection.clone().map(transaction.changes());
state.selection = state.selection.map(transaction.changes());
assert_eq!(state.doc, " 1\n\n 2\n 3");
// 0 margin comments
state.doc = Rope::from(" //1\n\n //2\n //3");
// reset the selection.
state.selection = Selection::single(0, state.doc.len_chars() - 1);
let transaction = toggle_line_comments(&state.doc, &state.selection, None);
transaction.apply(&mut state.doc);
state.selection = state.selection.map(transaction.changes());
assert_eq!(state.doc, " 1\n\n 2\n 3");
// TODO: account for no margin after comment
// TODO: account for uncommenting with uneven comment indentation
}
}