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-rw-r--r--crates/tt/src/buffer.rs105
1 files changed, 76 insertions, 29 deletions
diff --git a/crates/tt/src/buffer.rs b/crates/tt/src/buffer.rs
index 02c771f70..3606c887d 100644
--- a/crates/tt/src/buffer.rs
+++ b/crates/tt/src/buffer.rs
@@ -1,6 +1,6 @@
1//! FIXME: write short doc here 1//! FIXME: write short doc here
2 2
3use crate::{Subtree, TokenTree}; 3use crate::{Leaf, Subtree, TokenTree};
4 4
5#[derive(Copy, Clone, Debug, Eq, PartialEq)] 5#[derive(Copy, Clone, Debug, Eq, PartialEq)]
6struct EntryId(usize); 6struct EntryId(usize);
@@ -13,7 +13,7 @@ struct EntryPtr(EntryId, usize);
13#[derive(Debug)] 13#[derive(Debug)]
14enum Entry<'t> { 14enum Entry<'t> {
15 // Mimicking types from proc-macro. 15 // Mimicking types from proc-macro.
16 Subtree(&'t TokenTree, EntryId), 16 Subtree(Option<&'t TokenTree>, &'t Subtree, EntryId),
17 Leaf(&'t TokenTree), 17 Leaf(&'t TokenTree),
18 // End entries contain a pointer to the entry from the containing 18 // End entries contain a pointer to the entry from the containing
19 // token tree, or None if this is the outermost level. 19 // token tree, or None if this is the outermost level.
@@ -27,37 +27,64 @@ pub struct TokenBuffer<'t> {
27 buffers: Vec<Box<[Entry<'t>]>>, 27 buffers: Vec<Box<[Entry<'t>]>>,
28} 28}
29 29
30impl<'t> TokenBuffer<'t> { 30trait TokenList<'a> {
31 pub fn new(tokens: &'t [TokenTree]) -> TokenBuffer<'t> { 31 fn entries(&self) -> (Vec<(usize, (&'a Subtree, Option<&'a TokenTree>))>, Vec<Entry<'a>>);
32 let mut buffers = vec![]; 32}
33
34 let idx = TokenBuffer::new_inner(tokens, &mut buffers, None);
35 assert_eq!(idx, 0);
36
37 TokenBuffer { buffers }
38 }
39 33
40 fn new_inner( 34impl<'a> TokenList<'a> for &'a [TokenTree] {
41 tokens: &'t [TokenTree], 35 fn entries(&self) -> (Vec<(usize, (&'a Subtree, Option<&'a TokenTree>))>, Vec<Entry<'a>>) {
42 buffers: &mut Vec<Box<[Entry<'t>]>>,
43 next: Option<EntryPtr>,
44 ) -> usize {
45 // Must contain everything in tokens and then the Entry::End 36 // Must contain everything in tokens and then the Entry::End
46 let start_capacity = tokens.len() + 1; 37 let start_capacity = self.len() + 1;
47 let mut entries = Vec::with_capacity(start_capacity); 38 let mut entries = Vec::with_capacity(start_capacity);
48 let mut children = vec![]; 39 let mut children = vec![];
49 40 for (idx, tt) in self.iter().enumerate() {
50 for (idx, tt) in tokens.iter().enumerate() {
51 match tt { 41 match tt {
52 TokenTree::Leaf(_) => { 42 TokenTree::Leaf(_) => {
53 entries.push(Entry::Leaf(tt)); 43 entries.push(Entry::Leaf(tt));
54 } 44 }
55 TokenTree::Subtree(subtree) => { 45 TokenTree::Subtree(subtree) => {
56 entries.push(Entry::End(None)); 46 entries.push(Entry::End(None));
57 children.push((idx, (subtree, tt))); 47 children.push((idx, (subtree, Some(tt))));
58 } 48 }
59 } 49 }
60 } 50 }
51 (children, entries)
52 }
53}
54
55impl<'a> TokenList<'a> for &'a Subtree {
56 fn entries(&self) -> (Vec<(usize, (&'a Subtree, Option<&'a TokenTree>))>, Vec<Entry<'a>>) {
57 // Must contain everything in tokens and then the Entry::End
58 let mut entries = vec![];
59 let mut children = vec![];
60 entries.push(Entry::End(None));
61 children.push((0usize, (*self, None)));
62 (children, entries)
63 }
64}
65
66impl<'t> TokenBuffer<'t> {
67 pub fn from_tokens(tokens: &'t [TokenTree]) -> TokenBuffer<'t> {
68 Self::new(tokens)
69 }
70
71 pub fn from_subtree(subtree: &'t Subtree) -> TokenBuffer<'t> {
72 Self::new(subtree)
73 }
74
75 fn new<T: TokenList<'t>>(tokens: T) -> TokenBuffer<'t> {
76 let mut buffers = vec![];
77 let idx = TokenBuffer::new_inner(tokens, &mut buffers, None);
78 assert_eq!(idx, 0);
79 TokenBuffer { buffers }
80 }
81
82 fn new_inner<T: TokenList<'t>>(
83 tokens: T,
84 buffers: &mut Vec<Box<[Entry<'t>]>>,
85 next: Option<EntryPtr>,
86 ) -> usize {
87 let (children, mut entries) = tokens.entries();
61 88
62 entries.push(Entry::End(next)); 89 entries.push(Entry::End(next));
63 let res = buffers.len(); 90 let res = buffers.len();
@@ -65,11 +92,11 @@ impl<'t> TokenBuffer<'t> {
65 92
66 for (child_idx, (subtree, tt)) in children { 93 for (child_idx, (subtree, tt)) in children {
67 let idx = TokenBuffer::new_inner( 94 let idx = TokenBuffer::new_inner(
68 &subtree.token_trees, 95 subtree.token_trees.as_slice(),
69 buffers, 96 buffers,
70 Some(EntryPtr(EntryId(res), child_idx + 1)), 97 Some(EntryPtr(EntryId(res), child_idx + 1)),
71 ); 98 );
72 buffers[res].as_mut()[child_idx] = Entry::Subtree(tt, EntryId(idx)); 99 buffers[res].as_mut()[child_idx] = Entry::Subtree(tt, subtree, EntryId(idx));
73 } 100 }
74 101
75 res 102 res
@@ -87,6 +114,24 @@ impl<'t> TokenBuffer<'t> {
87 } 114 }
88} 115}
89 116
117#[derive(Debug)]
118pub enum TokenTreeRef<'a> {
119 Subtree(&'a Subtree, Option<&'a TokenTree>),
120 Leaf(&'a Leaf, &'a TokenTree),
121}
122
123impl<'a> TokenTreeRef<'a> {
124 pub fn cloned(&self) -> TokenTree {
125 match &self {
126 TokenTreeRef::Subtree(subtree, tt) => match tt {
127 Some(it) => (*it).clone(),
128 None => (*subtree).clone().into(),
129 },
130 TokenTreeRef::Leaf(_, tt) => (*tt).clone(),
131 }
132 }
133}
134
90/// A safe version of `Cursor` from `syn` crate https://github.com/dtolnay/syn/blob/6533607f91686545cb034d2838beea338d9d0742/src/buffer.rs#L125 135/// A safe version of `Cursor` from `syn` crate https://github.com/dtolnay/syn/blob/6533607f91686545cb034d2838beea338d9d0742/src/buffer.rs#L125
91#[derive(Copy, Clone, Debug)] 136#[derive(Copy, Clone, Debug)]
92pub struct Cursor<'a> { 137pub struct Cursor<'a> {
@@ -114,12 +159,11 @@ impl<'a> Cursor<'a> {
114 match self.entry() { 159 match self.entry() {
115 Some(Entry::End(Some(ptr))) => { 160 Some(Entry::End(Some(ptr))) => {
116 let idx = ptr.1; 161 let idx = ptr.1;
117 if let Some(Entry::Subtree(TokenTree::Subtree(subtree), _)) = 162 if let Some(Entry::Subtree(_, subtree, _)) =
118 self.buffer.entry(&EntryPtr(ptr.0, idx - 1)) 163 self.buffer.entry(&EntryPtr(ptr.0, idx - 1))
119 { 164 {
120 return Some(subtree); 165 return Some(subtree);
121 } 166 }
122
123 None 167 None
124 } 168 }
125 _ => None, 169 _ => None,
@@ -134,7 +178,7 @@ impl<'a> Cursor<'a> {
134 /// a cursor into that subtree 178 /// a cursor into that subtree
135 pub fn subtree(self) -> Option<Cursor<'a>> { 179 pub fn subtree(self) -> Option<Cursor<'a>> {
136 match self.entry() { 180 match self.entry() {
137 Some(Entry::Subtree(_, entry_id)) => { 181 Some(Entry::Subtree(_, _, entry_id)) => {
138 Some(Cursor::create(self.buffer, EntryPtr(*entry_id, 0))) 182 Some(Cursor::create(self.buffer, EntryPtr(*entry_id, 0)))
139 } 183 }
140 _ => None, 184 _ => None,
@@ -142,10 +186,13 @@ impl<'a> Cursor<'a> {
142 } 186 }
143 187
144 /// If the cursor is pointing at a `TokenTree`, returns it 188 /// If the cursor is pointing at a `TokenTree`, returns it
145 pub fn token_tree(self) -> Option<&'a TokenTree> { 189 pub fn token_tree(self) -> Option<TokenTreeRef<'a>> {
146 match self.entry() { 190 match self.entry() {
147 Some(Entry::Leaf(tt)) => Some(tt), 191 Some(Entry::Leaf(tt)) => match tt {
148 Some(Entry::Subtree(tt, _)) => Some(tt), 192 TokenTree::Leaf(leaf) => Some(TokenTreeRef::Leaf(leaf, *tt)),
193 TokenTree::Subtree(subtree) => Some(TokenTreeRef::Subtree(subtree, Some(tt))),
194 },
195 Some(Entry::Subtree(tt, subtree, _)) => Some(TokenTreeRef::Subtree(subtree, *tt)),
149 Some(Entry::End(_)) => None, 196 Some(Entry::End(_)) => None,
150 None => None, 197 None => None,
151 } 198 }
@@ -172,7 +219,7 @@ impl<'a> Cursor<'a> {
172 /// a cursor into that subtree 219 /// a cursor into that subtree
173 pub fn bump_subtree(self) -> Cursor<'a> { 220 pub fn bump_subtree(self) -> Cursor<'a> {
174 match self.entry() { 221 match self.entry() {
175 Some(Entry::Subtree(_, _)) => self.subtree().unwrap(), 222 Some(Entry::Subtree(_, _, _)) => self.subtree().unwrap(),
176 _ => self.bump(), 223 _ => self.bump(),
177 } 224 }
178 } 225 }