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
|
//! This module defines `AssistCtx` -- the API surface that is exposed to assists.
use hir::{db::HirDatabase, InFile, SourceAnalyzer};
use ra_db::FileRange;
use ra_fmt::{leading_indent, reindent};
use ra_syntax::{
algo::{self, find_covering_element, find_node_at_offset},
AstNode, SourceFile, SyntaxElement, SyntaxKind, SyntaxNode, SyntaxToken, TextRange, TextUnit,
TokenAtOffset,
};
use ra_text_edit::TextEditBuilder;
use crate::{AssistAction, AssistId, AssistLabel};
#[derive(Clone, Debug)]
pub(crate) enum Assist {
Unresolved { label: AssistLabel },
Resolved { label: AssistLabel, action: AssistAction },
}
/// `AssistCtx` allows to apply an assist or check if it could be applied.
///
/// Assists use a somewhat over-engineered approach, given the current needs. The
/// assists workflow consists of two phases. In the first phase, a user asks for
/// the list of available assists. In the second phase, the user picks a
/// particular assist and it gets applied.
///
/// There are two peculiarities here:
///
/// * first, we ideally avoid computing more things then necessary to answer
/// "is assist applicable" in the first phase.
/// * second, when we are applying assist, we don't have a guarantee that there
/// weren't any changes between the point when user asked for assists and when
/// they applied a particular assist. So, when applying assist, we need to do
/// all the checks from scratch.
///
/// To avoid repeating the same code twice for both "check" and "apply"
/// functions, we use an approach reminiscent of that of Django's function based
/// views dealing with forms. Each assist receives a runtime parameter,
/// `should_compute_edit`. It first check if an edit is applicable (potentially
/// computing info required to compute the actual edit). If it is applicable,
/// and `should_compute_edit` is `true`, it then computes the actual edit.
///
/// So, to implement the original assists workflow, we can first apply each edit
/// with `should_compute_edit = false`, and then applying the selected edit
/// again, with `should_compute_edit = true` this time.
///
/// Note, however, that we don't actually use such two-phase logic at the
/// moment, because the LSP API is pretty awkward in this place, and it's much
/// easier to just compute the edit eagerly :-)
#[derive(Debug)]
pub(crate) struct AssistCtx<'a, DB> {
pub(crate) db: &'a DB,
pub(crate) frange: FileRange,
source_file: SourceFile,
should_compute_edit: bool,
}
impl<'a, DB> Clone for AssistCtx<'a, DB> {
fn clone(&self) -> Self {
AssistCtx {
db: self.db,
frange: self.frange,
source_file: self.source_file.clone(),
should_compute_edit: self.should_compute_edit,
}
}
}
impl<'a, DB: HirDatabase> AssistCtx<'a, DB> {
pub(crate) fn with_ctx<F, T>(db: &DB, frange: FileRange, should_compute_edit: bool, f: F) -> T
where
F: FnOnce(AssistCtx<DB>) -> T,
{
let parse = db.parse(frange.file_id);
let ctx = AssistCtx { db, frange, source_file: parse.tree(), should_compute_edit };
f(ctx)
}
pub(crate) fn add_assist(
self,
id: AssistId,
label: impl Into<String>,
f: impl FnOnce(&mut AssistBuilder),
) -> Option<Assist> {
let label = AssistLabel { label: label.into(), id };
assert!(label.label.chars().nth(0).unwrap().is_uppercase());
let assist = if self.should_compute_edit {
let action = {
let mut edit = AssistBuilder::default();
f(&mut edit);
edit.build()
};
Assist::Resolved { label, action }
} else {
Assist::Unresolved { label }
};
Some(assist)
}
pub(crate) fn token_at_offset(&self) -> TokenAtOffset<SyntaxToken> {
self.source_file.syntax().token_at_offset(self.frange.range.start())
}
pub(crate) fn find_token_at_offset(&self, kind: SyntaxKind) -> Option<SyntaxToken> {
self.token_at_offset().find(|it| it.kind() == kind)
}
pub(crate) fn find_node_at_offset<N: AstNode>(&self) -> Option<N> {
find_node_at_offset(self.source_file.syntax(), self.frange.range.start())
}
pub(crate) fn covering_element(&self) -> SyntaxElement {
find_covering_element(self.source_file.syntax(), self.frange.range)
}
pub(crate) fn source_analyzer(
&self,
node: &SyntaxNode,
offset: Option<TextUnit>,
) -> SourceAnalyzer {
SourceAnalyzer::new(self.db, InFile::new(self.frange.file_id.into(), node), offset)
}
pub(crate) fn covering_node_for_range(&self, range: TextRange) -> SyntaxElement {
find_covering_element(self.source_file.syntax(), range)
}
}
#[derive(Default)]
pub(crate) struct AssistBuilder {
edit: TextEditBuilder,
cursor_position: Option<TextUnit>,
target: Option<TextRange>,
}
impl AssistBuilder {
/// Replaces specified `range` of text with a given string.
pub(crate) fn replace(&mut self, range: TextRange, replace_with: impl Into<String>) {
self.edit.replace(range, replace_with.into())
}
/// Replaces specified `node` of text with a given string, reindenting the
/// string to maintain `node`'s existing indent.
// FIXME: remove in favor of ra_syntax::edit::IndentLevel::increase_indent
pub(crate) fn replace_node_and_indent(
&mut self,
node: &SyntaxNode,
replace_with: impl Into<String>,
) {
let mut replace_with = replace_with.into();
if let Some(indent) = leading_indent(node) {
replace_with = reindent(&replace_with, &indent)
}
self.replace(node.text_range(), replace_with)
}
/// Remove specified `range` of text.
#[allow(unused)]
pub(crate) fn delete(&mut self, range: TextRange) {
self.edit.delete(range)
}
/// Append specified `text` at the given `offset`
pub(crate) fn insert(&mut self, offset: TextUnit, text: impl Into<String>) {
self.edit.insert(offset, text.into())
}
/// Specify desired position of the cursor after the assist is applied.
pub(crate) fn set_cursor(&mut self, offset: TextUnit) {
self.cursor_position = Some(offset)
}
/// Specify that the assist should be active withing the `target` range.
///
/// Target ranges are used to sort assists: the smaller the target range,
/// the more specific assist is, and so it should be sorted first.
pub(crate) fn target(&mut self, target: TextRange) {
self.target = Some(target)
}
/// Get access to the raw `TextEditBuilder`.
pub(crate) fn text_edit_builder(&mut self) -> &mut TextEditBuilder {
&mut self.edit
}
pub(crate) fn replace_ast<N: AstNode>(&mut self, old: N, new: N) {
algo::diff(old.syntax(), new.syntax()).into_text_edit(&mut self.edit)
}
fn build(self) -> AssistAction {
AssistAction {
edit: self.edit.finish(),
cursor_position: self.cursor_position,
target: self.target,
}
}
}
|
