xi-core-lib 0.3.0

// Copyright 2018 The xi-editor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! Module for searching text.

use std::cmp::{max, min};
use std::iter;

use crate::annotations::{AnnotationRange, AnnotationSlice, AnnotationType, ToAnnotation};
use crate::selection::{InsertDrift, SelRegion, Selection};
use crate::view::View;
use crate::word_boundaries::WordCursor;
use regex::{Regex, RegexBuilder};
use xi_rope::delta::DeltaRegion;
use xi_rope::find::{find, is_multiline_regex, CaseMatching};
use xi_rope::{Cursor, Interval, LinesMetric, Metric, Rope, RopeDelta};

const REGEX_SIZE_LIMIT: usize = 1000000;

/// Information about search queries and number of matches for find
#[derive(Serialize, Deserialize, Debug)]
pub struct FindStatus {
    /// Identifier for the current search query.
    id: usize,

    /// The current search query.
    chars: Option<String>,

    /// Whether the active search is case matching.
    case_sensitive: Option<bool>,

    /// Whether the search query is considered as regular expression.
    is_regex: Option<bool>,

    /// Query only matches whole words.
    whole_words: Option<bool>,

    /// Total number of matches.
    matches: usize,

    /// Line numbers which have find results.
    lines: Vec<usize>,
}

/// Contains logic to search text
pub struct Find {
    /// Uniquely identifies this search query.
    id: usize,

    /// The occurrences, which determine the highlights, have been updated.
    hls_dirty: bool,

    /// The currently active search string.
    search_string: Option<String>,

    /// The case matching setting for the currently active search.
    case_matching: CaseMatching,

    /// The search query should be considered as regular expression.
    regex: Option<Regex>,

    /// Query matches only whole words.
    whole_words: bool,

    /// The set of all known find occurrences (highlights).
    occurrences: Selection,
}

impl Find {
    pub fn new(id: usize) -> Find {
        Find {
            id,
            hls_dirty: true,
            search_string: None,
            case_matching: CaseMatching::CaseInsensitive,
            regex: None,
            whole_words: false,
            occurrences: Selection::new(),
        }
    }

    pub fn id(&self) -> usize {
        self.id
    }

    pub fn occurrences(&self) -> &Selection {
        &self.occurrences
    }

    pub fn hls_dirty(&self) -> bool {
        self.hls_dirty
    }

    pub fn find_status(&self, view: &View, text: &Rope, matches_only: bool) -> FindStatus {
        if matches_only {
            FindStatus {
                id: self.id,
                chars: None,
                case_sensitive: None,
                is_regex: None,
                whole_words: None,
                matches: self.occurrences.len(),
                lines: Vec::new(),
            }
        } else {
            FindStatus {
                id: self.id,
                chars: self.search_string.clone(),
                case_sensitive: Some(self.case_matching == CaseMatching::Exact),
                is_regex: Some(self.regex.is_some()),
                whole_words: Some(self.whole_words),
                matches: self.occurrences.len(),
                lines: self
                    .occurrences
                    .iter()
                    .map(|o| view.offset_to_line_col(text, o.min()).0 + 1)
                    .collect(),
            }
        }
    }

    pub fn set_hls_dirty(&mut self, is_dirty: bool) {
        self.hls_dirty = is_dirty
    }

    pub fn update_highlights(&mut self, text: &Rope, delta: &RopeDelta) {
        // update search highlights for changed regions
        if self.search_string.is_some() {
            // invalidate occurrences around deletion positions
            for DeltaRegion { old_offset, len, .. } in delta.iter_deletions() {
                self.occurrences.delete_range(old_offset, old_offset + len, false);
            }

            self.occurrences = self.occurrences.apply_delta(delta, false, InsertDrift::Default);

            // invalidate occurrences around insert positions
            for DeltaRegion { new_offset, len, .. } in delta.iter_inserts() {
                // also invalidate previous occurrence since it might expand after insertion
                // eg. for regex .* every insertion after match will be part of match
                self.occurrences.delete_range(
                    new_offset.checked_sub(1).unwrap_or(0),
                    new_offset + len,
                    false,
                );
            }

            // update find for the whole delta and everything after
            let (iv, new_len) = delta.summary();

            // get last valid occurrence that was unaffected by the delta
            let start = match self.occurrences.regions_in_range(0, iv.start()).last() {
                Some(reg) => reg.end,
                None => 0,
            };

            // invalidate all search results from the point of the last valid search result until ...
            let is_multiline = LinesMetric::next(self.search_string.as_ref().unwrap(), 0).is_some();

            if is_multiline || self.is_multiline_regex() {
                // ... the end of the file
                self.occurrences.delete_range(iv.start(), text.len(), false);
                self.update_find(text, start, text.len(), false);
            } else {
                // ... the end of the line including line break
                let mut cursor = Cursor::new(&text, iv.end() + new_len);

                let end_of_line = match cursor.next::<LinesMetric>() {
                    Some(end) => end,
                    None if cursor.pos() == text.len() => cursor.pos(),
                    _ => return,
                };

                self.occurrences.delete_range(iv.start(), end_of_line, false);
                self.update_find(text, start, end_of_line, false);
            }
        }
    }

    /// Returns `true` if the search query is a multi-line regex.
    pub(crate) fn is_multiline_regex(&self) -> bool {
        self.regex.is_some() && is_multiline_regex(self.search_string.as_ref().unwrap())
    }

    /// Unsets the search and removes all highlights from the view.
    pub fn unset(&mut self) {
        self.search_string = None;
        self.occurrences = Selection::new();
        self.hls_dirty = true;
    }

    /// Sets find parameters and search query. Returns `true` if parameters have been updated.
    /// Returns `false` to indicate that parameters haven't change.
    pub(crate) fn set_find(
        &mut self,
        search_string: &str,
        case_sensitive: bool,
        is_regex: bool,
        whole_words: bool,
    ) -> bool {
        if search_string.is_empty() {
            self.unset();
        }

        let case_matching =
            if case_sensitive { CaseMatching::Exact } else { CaseMatching::CaseInsensitive };

        if let Some(ref s) = self.search_string {
            if s == search_string
                && case_matching == self.case_matching
                && self.regex.is_some() == is_regex
                && self.whole_words == whole_words
            {
                // search parameters did not change
                return false;
            }
        }

        self.unset();

        self.search_string = Some(search_string.to_string());
        self.case_matching = case_matching;
        self.whole_words = whole_words;

        // create regex from untrusted input
        self.regex = match is_regex {
            false => None,
            true => RegexBuilder::new(search_string)
                .size_limit(REGEX_SIZE_LIMIT)
                .case_insensitive(case_matching == CaseMatching::CaseInsensitive)
                .build()
                .ok(),
        };

        true
    }

    /// Execute the search on the provided text in the range provided by `start` and `end`.
    pub fn update_find(&mut self, text: &Rope, start: usize, end: usize, include_slop: bool) {
        if self.search_string.is_none() {
            return;
        }

        // extend the search by twice the string length (twice, because case matching may increase
        // the length of an occurrence)
        let slop = if include_slop { self.search_string.as_ref().unwrap().len() * 2 } else { 0 };

        let search_string = self.search_string.as_ref().unwrap();

        // expand region to be able to find occurrences around the region's edges
        let expanded_start = max(start, slop) - slop;
        let expanded_end = min(end + slop, text.len());
        let from = text.at_or_prev_codepoint_boundary(expanded_start).unwrap_or(0);
        let to = text.at_or_next_codepoint_boundary(expanded_end).unwrap_or(text.len());
        let mut to_cursor = Cursor::new(&text, to);
        let _ = to_cursor.next_leaf();

        let sub_text = text.subseq(Interval::new(0, to_cursor.pos()));
        let mut find_cursor = Cursor::new(&sub_text, from);

        let mut raw_lines = text.lines_raw(from..to);

        while let Some(start) = find(
            &mut find_cursor,
            &mut raw_lines,
            self.case_matching,
            &search_string,
            self.regex.as_ref(),
        ) {
            let end = find_cursor.pos();

            if self.whole_words && !self.is_matching_whole_words(text, start, end) {
                raw_lines = text.lines_raw(find_cursor.pos()..to);
                continue;
            }

            let region = SelRegion::new(start, end);
            let (_, e) = self.occurrences.add_range_distinct(region);
            // in case of ambiguous search results (e.g. search "aba" in "ababa"),
            // the search result closer to the beginning of the file wins
            if e != end {
                // Skip the search result and keep the occurrence that is closer to
                // the beginning of the file. Re-align the cursor to the kept
                // occurrence
                find_cursor.set(e);
                raw_lines = text.lines_raw(find_cursor.pos()..to);
                continue;
            }

            // in case current cursor matches search result (for example query a* matches)
            // all cursor positions, then cursor needs to be increased so that search
            // continues at next position. Otherwise, search will result in overflow since
            // search will always repeat at current cursor position.
            if start == end {
                // determine whether end of text is reached and stop search or increase
                // cursor manually
                if end + 1 >= text.len() {
                    break;
                } else {
                    find_cursor.set(end + 1);
                }
            }

            // update line iterator so that line starts at current cursor position
            raw_lines = text.lines_raw(find_cursor.pos()..to);
        }

        self.hls_dirty = true;
    }

    /// Return the occurrence closest to the provided selection `sel`. If searched is reversed then
    /// the occurrence closest to the start of the selection is returned. `wrapped` indicates that
    /// if the end of the text is reached the search continues from the start.
    pub fn next_occurrence(
        &self,
        text: &Rope,
        reverse: bool,
        wrapped: bool,
        sel: &Selection,
    ) -> Option<SelRegion> {
        if self.occurrences.len() == 0 {
            return None;
        }

        let (sel_start, sel_end) = match sel.last() {
            Some(last) if last.is_caret() =>
            // if last selection is caret then allow the current position to be part of the occurrence
            {
                (last.min(), last.max())
            }
            Some(last) if !last.is_caret() =>
            // if the last selection is not a caret then continue searching after the caret
            {
                (last.min(), last.max() + 1)
            }
            _ => (0, 0),
        };

        if reverse {
            let next_occurrence = match sel_start.checked_sub(1) {
                Some(search_end) => self.occurrences.regions_in_range(0, search_end).last(),
                None => None,
            };

            if next_occurrence.is_none() && !wrapped {
                // get previous unselected occurrence
                return self
                    .occurrences
                    .regions_in_range(0, text.len())
                    .iter()
                    .cloned()
                    .filter(|o| sel.regions_in_range(o.min(), o.max()).is_empty())
                    .collect::<Vec<SelRegion>>()
                    .last()
                    .cloned();
            }

            next_occurrence.cloned()
        } else {
            let next_occurrence = self.occurrences.regions_in_range(sel_end, text.len()).first();

            if next_occurrence.is_none() && !wrapped {
                // get next unselected occurrence
                return self
                    .occurrences
                    .regions_in_range(0, text.len())
                    .iter()
                    .cloned()
                    .filter(|o| sel.regions_in_range(o.min(), o.max()).is_empty())
                    .collect::<Vec<SelRegion>>()
                    .first()
                    .cloned();
            }

            next_occurrence.cloned()
        }
    }

    /// Checks if the start and end of a match is matching whole words.
    fn is_matching_whole_words(&self, text: &Rope, start: usize, end: usize) -> bool {
        let mut word_end_cursor = WordCursor::new(text, end - 1);
        let mut word_start_cursor = WordCursor::new(text, start + 1);

        if let Some(start_boundary) = word_start_cursor.prev_boundary() {
            if start_boundary != start {
                return false;
            }
        }

        if let Some(end_boundary) = word_end_cursor.next_boundary() {
            if end_boundary != end {
                return false;
            }
        }

        true
    }
}

/// Implementing the `ToAnnotation` trait allows to convert finds to annotations.
impl ToAnnotation for Find {
    fn get_annotations(&self, interval: Interval, view: &View, text: &Rope) -> AnnotationSlice {
        let regions = self.occurrences.regions_in_range(interval.start(), interval.end());
        let ranges = regions
            .iter()
            .map(|region| {
                let (start_line, start_col) = view.offset_to_line_col(text, region.min());
                let (end_line, end_col) = view.offset_to_line_col(text, region.max());

                AnnotationRange { start_line, start_col, end_line, end_col }
            })
            .collect::<Vec<AnnotationRange>>();

        let payload = iter::repeat(json!({"id": self.id})).take(ranges.len()).collect::<Vec<_>>();

        AnnotationSlice::new(AnnotationType::Find, ranges, Some(payload))
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use xi_rope::DeltaBuilder;

    #[test]
    fn find() {
        let base_text = Rope::from("hello world");
        let mut find = Find::new(1);
        find.set_find("world", false, false, false);
        find.update_find(&base_text, 0, base_text.len(), false);
        assert_eq!(find.occurrences().len(), 1);
        assert_eq!(find.occurrences().first(), Some(&SelRegion::new(6, 11)));
    }

    #[test]
    fn find_whole_words() {
        let base_text = Rope::from("hello world\n many worlds");
        let mut find = Find::new(1);
        find.set_find("world", false, false, true);
        find.update_find(&base_text, 0, base_text.len(), false);
        assert_eq!(find.occurrences().len(), 1);
        assert_eq!(find.occurrences().first(), Some(&SelRegion::new(6, 11)));
    }

    #[test]
    fn find_case_sensitive() {
        let base_text = Rope::from("hello world\n HELLO WORLD");
        let mut find = Find::new(1);
        find.set_find("world", true, false, false);
        find.update_find(&base_text, 0, base_text.len(), false);
        assert_eq!(find.occurrences().len(), 1);
        assert_eq!(find.occurrences().first(), Some(&SelRegion::new(6, 11)));
    }

    #[test]
    fn find_multiline() {
        let base_text = Rope::from("hello world\n HELLO WORLD");
        let mut find = Find::new(1);
        find.set_find("hello world\n HELLO", true, false, false);
        find.update_find(&base_text, 0, base_text.len(), false);
        assert_eq!(find.occurrences().len(), 1);
        assert_eq!(find.occurrences().first(), Some(&SelRegion::new(0, 18)));
    }

    #[test]
    fn find_regex() {
        let base_text = Rope::from("hello world\n HELLO WORLD");
        let mut find = Find::new(1);
        find.set_find("hello \\w+", false, true, false);
        find.update_find(&base_text, 0, base_text.len(), false);
        assert_eq!(find.occurrences().len(), 2);
        assert_eq!(find.occurrences().first(), Some(&SelRegion::new(0, 11)));

        find.set_find("h.llo", true, true, false);
        find.update_find(&base_text, 0, base_text.len(), false);
        assert_eq!(find.occurrences().len(), 1);
        assert_eq!(find.occurrences().first(), Some(&SelRegion::new(0, 5)));

        find.set_find(".*", false, true, false);
        find.update_find(&base_text, 0, base_text.len(), false);
        assert_eq!(find.occurrences().len(), 3);
        assert_eq!(find.occurrences().first(), Some(&SelRegion::new(0, 11)));
    }

    #[test]
    fn find_regex_multiline() {
        let base_text = Rope::from("hello world\n HELLO WORLD");
        let mut find = Find::new(1);
        find.set_find("(.*\n.*)+", true, true, false);
        find.update_find(&base_text, 0, base_text.len(), false);
        assert_eq!(find.occurrences().len(), 1);
        assert_eq!(find.occurrences().first(), Some(&SelRegion::new(0, 12)));
    }

    #[test]
    fn find_multiline_regex() {
        let mut find = Find::new(1);
        find.set_find("a", true, true, false);
        assert_eq!(find.is_multiline_regex(), false);
        find.set_find(".*", true, true, false);
        assert_eq!(find.is_multiline_regex(), false);
        find.set_find("\\n", true, true, false);
        assert_eq!(find.is_multiline_regex(), true);
    }

    #[test]
    fn find_slop() {
        let base_text = Rope::from("aaa bbb aaa bbb aaa x");
        let mut find = Find::new(1);
        find.set_find("aaa", true, true, false);
        find.update_find(&base_text, 2, base_text.len(), false);
        assert_eq!(find.occurrences().len(), 2);
        assert_eq!(find.occurrences().first(), Some(&SelRegion::new(8, 11)));

        find.update_find(&base_text, 3, base_text.len(), true);
        assert_eq!(find.occurrences().len(), 3);
        assert_eq!(find.occurrences().first(), Some(&SelRegion::new(0, 3)));
    }

    #[test]
    fn find_next_occurrence() {
        let base_text = Rope::from("aaa bbb aaa bbb aaa x");
        let mut find = Find::new(1);
        find.set_find("aaa", true, true, false);
        find.update_find(&base_text, 0, base_text.len(), false);
        assert_eq!(find.occurrences().len(), 3);
        assert_eq!(
            find.next_occurrence(&base_text, false, false, &Selection::new()),
            Some(SelRegion::new(0, 3))
        );

        let mut prev_selection = Selection::new();
        prev_selection.add_region(SelRegion::new(0, 3));
        assert_eq!(
            find.next_occurrence(&base_text, false, false, &prev_selection),
            Some(SelRegion::new(8, 11))
        );

        let mut prev_selection = Selection::new();
        prev_selection.add_region(SelRegion::new(19, 19));
        assert_eq!(
            find.next_occurrence(&base_text, false, true, &prev_selection),
            Some(SelRegion::new(16, 19))
        );

        let mut prev_selection = Selection::new();
        prev_selection.add_region(SelRegion::new(20, 20));
        assert_eq!(
            find.next_occurrence(&base_text, false, false, &prev_selection),
            Some(SelRegion::new(0, 3))
        );
    }

    #[test]
    fn find_previous_occurrence() {
        let base_text = Rope::from("aaa bbb aaa bbb aaa x");
        let mut find = Find::new(1);
        find.set_find("aaa", true, true, false);
        find.update_find(&base_text, 0, base_text.len(), false);
        assert_eq!(find.occurrences().len(), 3);
        assert_eq!(
            find.next_occurrence(&base_text, true, false, &Selection::new()),
            Some(SelRegion::new(16, 19))
        );

        let mut prev_selection = Selection::new();
        prev_selection.add_region(SelRegion::new(20, 20));
        assert_eq!(find.next_occurrence(&base_text, true, true, &Selection::new()), None);
    }

    #[test]
    fn unset_find() {
        let base_text = Rope::from("aaa bbb aaa bbb aaa x");
        let mut find = Find::new(1);
        find.set_find("aaa", true, true, false);
        find.update_find(&base_text, 0, base_text.len(), false);
        assert_eq!(find.occurrences().len(), 3);
        find.unset();
        assert_eq!(find.occurrences().len(), 0);
    }

    #[test]
    fn update_find_edit() {
        let base_text = Rope::from("a b a c");
        let mut find = Find::new(1);
        find.set_find("a", false, false, false);
        find.update_find(&base_text, 0, base_text.len(), false);
        let mut builder = DeltaBuilder::new(base_text.len());
        builder.replace(0..0, "a ".into());

        assert_eq!(find.occurrences().len(), 2);
        assert_eq!(find.occurrences().first(), Some(&SelRegion::new(0, 1)));
        assert_eq!(find.occurrences().last(), Some(&SelRegion::new(4, 5)));
    }

    #[test]
    fn update_find_multiline_edit() {
        let base_text = Rope::from("x\n a\n b\n a\n c");
        let mut find = Find::new(1);
        find.set_find("a", false, false, false);
        find.update_find(&base_text, 0, base_text.len(), false);
        let mut builder = DeltaBuilder::new(base_text.len());
        builder.replace(2..2, " a\n b\n a\n".into());

        assert_eq!(find.occurrences().len(), 2);
        assert_eq!(find.occurrences().first(), Some(&SelRegion::new(3, 4)));
        assert_eq!(find.occurrences().last(), Some(&SelRegion::new(9, 10)));
    }
}