1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199

use super::pos::*;
use super::text_info::*;
use super::tokens::*;
use crate::swc::common::comments::Comment;
use crate::swc::common::comments::SingleThreadedCommentsMapInner;

pub struct CommentContainer<'a> {
  pub leading: &'a SingleThreadedCommentsMapInner,
  pub trailing: &'a SingleThreadedCommentsMapInner,
  tokens: &'a TokenContainer<'a>,
  text_info: &'a SourceTextInfo,
}

impl<'a> CommentContainer<'a> {
  pub fn new(
    leading: &'a SingleThreadedCommentsMapInner,
    trailing: &'a SingleThreadedCommentsMapInner,
    tokens: &'a TokenContainer<'a>,
    text_info: &'a SourceTextInfo,
  ) -> Self {
    CommentContainer {
      leading,
      trailing,
      tokens,
      text_info,
    }
  }

  pub fn all_comments(&'a self) -> CommentsIterator<'a> {
    let approx_cap = self.leading.len() + self.trailing.len();
    let mut v = Vec::with_capacity(approx_cap);
    v.extend(self.leading.values());
    v.extend(self.trailing.values());
    CommentsIterator::new(v)
  }

  pub fn leading_comments(&'a self, start: SourcePos) -> CommentsIterator<'a> {
    let previous_token_hi = self.tokens.get_token_index_at_start(start).map(|index| {
      if index == 0 {
        self.text_info.range().start.as_source_pos()
      } else {
        self.tokens.get_token_at_index(index - 1).unwrap().end()
      }
    });
    let leading = self.get_leading(start);
    if let Some(previous_token_hi) = previous_token_hi {
      let trailing = self.get_trailing(previous_token_hi);
      combine_comment_vecs(trailing, leading)
    } else {
      leading.map(|l| CommentsIterator::new(vec![l])).unwrap_or_default()
    }
  }

  pub fn trailing_comments(&'a self, end: SourcePos) -> CommentsIterator<'a> {
    let next_token_lo = self.tokens.get_token_index_at_end(end).map(|index| {
      self
        .tokens
        .get_token_at_index(index + 1)
        .map(|t| t.start())
        .unwrap_or_else(|| self.text_info.range().end)
    });
    let trailing = self.get_trailing(end);
    if let Some(next_token_lo) = next_token_lo {
      let leading = self.get_leading(next_token_lo);
      combine_comment_vecs(trailing, leading)
    } else {
      trailing.map(|t| CommentsIterator::new(vec![t])).unwrap_or_default()
    }
  }

  fn get_leading(&'a self, start: SourcePos) -> Option<&'a Vec<Comment>> {
    self.leading.get(&start.as_byte_pos())
  }

  fn get_trailing(&'a self, end: SourcePos) -> Option<&'a Vec<Comment>> {
    self.trailing.get(&end.as_byte_pos())
  }
}

fn combine_comment_vecs<'a>(a: Option<&'a Vec<Comment>>, b: Option<&'a Vec<Comment>>) -> CommentsIterator<'a> {
  let length = if a.is_some() { 1 } else { 0 } + if b.is_some() { 1 } else { 0 };
  let mut comment_vecs = Vec::with_capacity(length);
  if let Some(a) = a {
    comment_vecs.push(a);
  }
  if let Some(b) = b {
    comment_vecs.push(b);
  }
  CommentsIterator::new(comment_vecs)
}

#[derive(Clone)]
pub struct CommentsIterator<'a> {
  comment_vecs: Vec<&'a Vec<Comment>>,
  outer_index: usize,
  inner_index: usize,
  outer_index_back: usize,
  inner_index_back: usize,
}

impl<'a> CommentsIterator<'a> {
  pub fn empty() -> Self {
    Self::new(Vec::with_capacity(0))
  }

  pub fn new(comment_vecs: Vec<&'a Vec<Comment>>) -> Self {
    let outer_index_back = comment_vecs.len();
    CommentsIterator {
      comment_vecs,
      outer_index: 0,
      inner_index: 0,
      outer_index_back,
      inner_index_back: 0,
    }
  }

  pub fn reset(&mut self) {
    self.outer_index = 0;
    self.inner_index = 0;
  }

  pub fn extend(&mut self, iterator: CommentsIterator<'a>) {
    self.comment_vecs.extend(iterator.comment_vecs);

    // reset the back iterator
    self.outer_index_back = self.comment_vecs.len();
    self.inner_index_back = 0;
  }

  pub fn is_empty(&self) -> bool {
    for comments in self.comment_vecs.iter() {
      if !comments.is_empty() {
        return false;
      }
    }

    true
  }

  pub fn peek_last_comment(&self) -> Option<&'a Comment> {
    if let Some(comments) = self.comment_vecs.last() {
      comments.last()
    } else {
      None
    }
  }
}

impl<'a> Default for CommentsIterator<'a> {
  fn default() -> Self {
    Self::empty()
  }
}

impl<'a> Iterator for CommentsIterator<'a> {
  type Item = &'a Comment;

  fn next(&mut self) -> Option<&'a Comment> {
    loop {
      if let Some(comments) = self.comment_vecs.get(self.outer_index) {
        if let Some(comment) = comments.get(self.inner_index) {
          self.inner_index += 1;
          return Some(comment);
        } else {
          self.inner_index = 0;
          self.outer_index += 1;
        }
      } else {
        return None;
      }
    }
  }

  fn size_hint(&self) -> (usize, Option<usize>) {
    let mut next_inner_index = self.inner_index;
    let mut count = 0;
    for comment_vec in &self.comment_vecs[self.outer_index..] {
      count += comment_vec.len() - next_inner_index;
      next_inner_index = 0;
    }
    (count, Some(count))
  }
}

impl<'a> DoubleEndedIterator for CommentsIterator<'a> {
  fn next_back(&mut self) -> Option<&'a Comment> {
    if self.inner_index_back == 0 {
      if self.outer_index_back == 0 {
        return None;
      }
      self.outer_index_back -= 1;
      self.inner_index_back = self.comment_vecs.get(self.outer_index_back).unwrap().len() - 1;
    } else {
      self.inner_index_back -= 1;
    }

    self.comment_vecs.get(self.outer_index_back).and_then(|inner| inner.get(self.inner_index_back))
  }
}