summaryrefslogtreecommitdiffstats
path: root/servo/components/style/values/specified/grid.rs
blob: 8bfa4a363bcdf484a75370f96a464b997dcefcd1 (plain)
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
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

//! CSS handling for the computed value of
//! [grids](https://drafts.csswg.org/css-grid/)

use crate::parser::{Parse, ParserContext};
use crate::values::generics::grid::{GridTemplateComponent, ImplicitGridTracks, RepeatCount};
use crate::values::generics::grid::{LineNameList, TrackBreadth, TrackRepeat, TrackSize};
use crate::values::generics::grid::{TrackList, TrackListValue};
use crate::values::specified::{Integer, LengthPercentage};
use crate::values::{CSSFloat, CustomIdent};
use cssparser::{ParseError as CssParseError, Parser, Token};
use std::mem;
use style_traits::{ParseError, StyleParseErrorKind};

/// Parse a single flexible length.
pub fn parse_flex<'i, 't>(input: &mut Parser<'i, 't>) -> Result<CSSFloat, ParseError<'i>> {
    let location = input.current_source_location();
    match *input.next()? {
        Token::Dimension {
            value, ref unit, ..
        } if unit.eq_ignore_ascii_case("fr") && value.is_sign_positive() => Ok(value),
        ref t => Err(location.new_unexpected_token_error(t.clone())),
    }
}

impl<L> TrackBreadth<L> {
    fn parse_keyword<'i, 't>(input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
        #[derive(Parse)]
        enum TrackKeyword {
            Auto,
            MaxContent,
            MinContent,
        }

        Ok(match TrackKeyword::parse(input)? {
            TrackKeyword::Auto => TrackBreadth::Auto,
            TrackKeyword::MaxContent => TrackBreadth::MaxContent,
            TrackKeyword::MinContent => TrackBreadth::MinContent,
        })
    }
}

impl Parse for TrackBreadth<LengthPercentage> {
    fn parse<'i, 't>(
        context: &ParserContext,
        input: &mut Parser<'i, 't>,
    ) -> Result<Self, ParseError<'i>> {
        // FIXME: This and other callers in this file should use
        // NonNegativeLengthPercentage instead.
        //
        // Though it seems these cannot be animated so it's ~ok.
        if let Ok(lp) = input.try_parse(|i| LengthPercentage::parse_non_negative(context, i)) {
            return Ok(TrackBreadth::Breadth(lp));
        }

        if let Ok(f) = input.try_parse(parse_flex) {
            return Ok(TrackBreadth::Fr(f));
        }

        Self::parse_keyword(input)
    }
}

impl Parse for TrackSize<LengthPercentage> {
    fn parse<'i, 't>(
        context: &ParserContext,
        input: &mut Parser<'i, 't>,
    ) -> Result<Self, ParseError<'i>> {
        if let Ok(b) = input.try_parse(|i| TrackBreadth::parse(context, i)) {
            return Ok(TrackSize::Breadth(b));
        }

        if input
            .try_parse(|i| i.expect_function_matching("minmax"))
            .is_ok()
        {
            return input.parse_nested_block(|input| {
                let inflexible_breadth =
                    match input.try_parse(|i| LengthPercentage::parse_non_negative(context, i)) {
                        Ok(lp) => TrackBreadth::Breadth(lp),
                        Err(..) => TrackBreadth::parse_keyword(input)?,
                    };

                input.expect_comma()?;
                Ok(TrackSize::Minmax(
                    inflexible_breadth,
                    TrackBreadth::parse(context, input)?,
                ))
            });
        }

        input.expect_function_matching("fit-content")?;
        let lp = input.parse_nested_block(|i| LengthPercentage::parse_non_negative(context, i))?;
        Ok(TrackSize::FitContent(TrackBreadth::Breadth(lp)))
    }
}

impl Parse for ImplicitGridTracks<TrackSize<LengthPercentage>> {
    fn parse<'i, 't>(
        context: &ParserContext,
        input: &mut Parser<'i, 't>,
    ) -> Result<Self, ParseError<'i>> {
        use style_traits::{Separator, Space};
        let track_sizes = Space::parse(input, |i| TrackSize::parse(context, i))?;
        if track_sizes.len() == 1 && track_sizes[0].is_initial() {
            // A single track with the initial value is always represented by an empty slice.
            return Ok(Default::default());
        }
        return Ok(ImplicitGridTracks(track_sizes.into()));
    }
}

/// Parse the grid line names into a vector of owned strings.
///
/// <https://drafts.csswg.org/css-grid/#typedef-line-names>
pub fn parse_line_names<'i, 't>(
    input: &mut Parser<'i, 't>,
) -> Result<crate::OwnedSlice<CustomIdent>, ParseError<'i>> {
    input.expect_square_bracket_block()?;
    input.parse_nested_block(|input| {
        let mut values = vec![];
        while let Ok((loc, ident)) = input.try_parse(|i| -> Result<_, CssParseError<()>> {
            Ok((i.current_source_location(), i.expect_ident_cloned()?))
        }) {
            let ident = CustomIdent::from_ident(loc, &ident, &["span", "auto"])?;
            values.push(ident);
        }

        Ok(values.into())
    })
}

/// The type of `repeat` function (only used in parsing).
///
/// <https://drafts.csswg.org/css-grid/#typedef-track-repeat>
#[derive(Clone, Copy, Debug, PartialEq, SpecifiedValueInfo)]
#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
enum RepeatType {
    /// [`<auto-repeat>`](https://drafts.csswg.org/css-grid/#typedef-auto-repeat)
    Auto,
    /// [`<track-repeat>`](https://drafts.csswg.org/css-grid/#typedef-track-repeat)
    Normal,
    /// [`<fixed-repeat>`](https://drafts.csswg.org/css-grid/#typedef-fixed-repeat)
    Fixed,
}

impl TrackRepeat<LengthPercentage, Integer> {
    fn parse_with_repeat_type<'i, 't>(
        context: &ParserContext,
        input: &mut Parser<'i, 't>,
    ) -> Result<(Self, RepeatType), ParseError<'i>> {
        input
            .try_parse(|i| i.expect_function_matching("repeat").map_err(|e| e.into()))
            .and_then(|_| {
                input.parse_nested_block(|input| {
                    let count = RepeatCount::parse(context, input)?;
                    input.expect_comma()?;

                    let is_auto = count == RepeatCount::AutoFit || count == RepeatCount::AutoFill;
                    let mut repeat_type = if is_auto {
                        RepeatType::Auto
                    } else {
                        // <fixed-size> is a subset of <track-size>, so it should work for both
                        RepeatType::Fixed
                    };

                    let mut names = vec![];
                    let mut values = vec![];
                    let mut current_names;

                    loop {
                        current_names = input.try_parse(parse_line_names).unwrap_or_default();
                        if let Ok(track_size) = input.try_parse(|i| TrackSize::parse(context, i)) {
                            if !track_size.is_fixed() {
                                if is_auto {
                                    // should be <fixed-size> for <auto-repeat>
                                    return Err(input
                                        .new_custom_error(StyleParseErrorKind::UnspecifiedError));
                                }

                                if repeat_type == RepeatType::Fixed {
                                    repeat_type = RepeatType::Normal // <track-size> for sure
                                }
                            }

                            values.push(track_size);
                            names.push(current_names);
                        } else {
                            if values.is_empty() {
                                // expecting at least one <track-size>
                                return Err(
                                    input.new_custom_error(StyleParseErrorKind::UnspecifiedError)
                                );
                            }

                            names.push(current_names); // final `<line-names>`
                            break; // no more <track-size>, breaking
                        }
                    }

                    let repeat = TrackRepeat {
                        count,
                        track_sizes: values.into(),
                        line_names: names.into(),
                    };

                    Ok((repeat, repeat_type))
                })
            })
    }
}

impl Parse for TrackList<LengthPercentage, Integer> {
    fn parse<'i, 't>(
        context: &ParserContext,
        input: &mut Parser<'i, 't>,
    ) -> Result<Self, ParseError<'i>> {
        let mut current_names = vec![];
        let mut names = vec![];
        let mut values = vec![];

        // Whether we've parsed an `<auto-repeat>` value.
        let mut auto_repeat_index = None;
        // assume that everything is <fixed-size>. This flag is useful when we encounter <auto-repeat>
        let mut at_least_one_not_fixed = false;
        loop {
            current_names
                .extend_from_slice(&mut input.try_parse(parse_line_names).unwrap_or_default());
            if let Ok(track_size) = input.try_parse(|i| TrackSize::parse(context, i)) {
                if !track_size.is_fixed() {
                    at_least_one_not_fixed = true;
                    if auto_repeat_index.is_some() {
                        // <auto-track-list> only accepts <fixed-size> and <fixed-repeat>
                        return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError));
                    }
                }

                let vec = mem::replace(&mut current_names, vec![]);
                names.push(vec.into());
                values.push(TrackListValue::TrackSize(track_size));
            } else if let Ok((repeat, type_)) =
                input.try_parse(|i| TrackRepeat::parse_with_repeat_type(context, i))
            {
                match type_ {
                    RepeatType::Normal => {
                        at_least_one_not_fixed = true;
                        if auto_repeat_index.is_some() {
                            // only <fixed-repeat>
                            return Err(
                                input.new_custom_error(StyleParseErrorKind::UnspecifiedError)
                            );
                        }
                    },
                    RepeatType::Auto => {
                        if auto_repeat_index.is_some() || at_least_one_not_fixed {
                            // We've either seen <auto-repeat> earlier, or there's at least one non-fixed value
                            return Err(
                                input.new_custom_error(StyleParseErrorKind::UnspecifiedError)
                            );
                        }
                        auto_repeat_index = Some(values.len());
                    },
                    RepeatType::Fixed => {},
                }

                let vec = mem::replace(&mut current_names, vec![]);
                names.push(vec.into());
                values.push(TrackListValue::TrackRepeat(repeat));
            } else {
                if values.is_empty() && auto_repeat_index.is_none() {
                    return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError));
                }

                names.push(current_names.into());
                break;
            }
        }

        Ok(TrackList {
            auto_repeat_index: auto_repeat_index.unwrap_or(std::usize::MAX),
            values: values.into(),
            line_names: names.into(),
        })
    }
}

#[cfg(feature = "gecko")]
#[inline]
fn allow_grid_template_subgrids() -> bool {
    true
}

#[cfg(feature = "servo")]
#[inline]
fn allow_grid_template_subgrids() -> bool {
    false
}

#[cfg(feature = "gecko")]
#[inline]
fn allow_grid_template_masonry() -> bool {
    static_prefs::pref!("layout.css.grid-template-masonry-value.enabled")
}

#[cfg(feature = "servo")]
#[inline]
fn allow_grid_template_masonry() -> bool {
    false
}

impl Parse for GridTemplateComponent<LengthPercentage, Integer> {
    fn parse<'i, 't>(
        context: &ParserContext,
        input: &mut Parser<'i, 't>,
    ) -> Result<Self, ParseError<'i>> {
        if input.try_parse(|i| i.expect_ident_matching("none")).is_ok() {
            return Ok(GridTemplateComponent::None);
        }

        Self::parse_without_none(context, input)
    }
}

impl GridTemplateComponent<LengthPercentage, Integer> {
    /// Parses a `GridTemplateComponent<LengthPercentage>` except `none` keyword.
    pub fn parse_without_none<'i, 't>(
        context: &ParserContext,
        input: &mut Parser<'i, 't>,
    ) -> Result<Self, ParseError<'i>> {
        if allow_grid_template_subgrids() {
            if let Ok(t) = input.try_parse(|i| LineNameList::parse(context, i)) {
                return Ok(GridTemplateComponent::Subgrid(Box::new(t)));
            }
        }
        if allow_grid_template_masonry() {
            if input
                .try_parse(|i| i.expect_ident_matching("masonry"))
                .is_ok()
            {
                return Ok(GridTemplateComponent::Masonry);
            }
        }
        let track_list = TrackList::parse(context, input)?;
        Ok(GridTemplateComponent::TrackList(Box::new(track_list)))
    }
}