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
/* 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/. */

//! Value information for devtools.

use std::ops::Range;
use std::sync::Arc as StdArc;

use servo_arc::Arc;

use crate::arc_slice::ArcSlice;
use crate::owned_slice::OwnedSlice;

/// Type of value that a property supports. This is used by Gecko's
/// devtools to make sense about value it parses, and types listed
/// here should match InspectorPropertyType in InspectorUtils.webidl.
///
/// XXX This should really be a bitflags rather than a namespace mod,
/// but currently we cannot use bitflags in const.
#[allow(non_snake_case)]
pub mod CssType {
    /// <color>
    pub const COLOR: u8 = 1 << 0;
    /// <gradient>
    pub const GRADIENT: u8 = 1 << 1;
    /// <timing-function>
    pub const TIMING_FUNCTION: u8 = 1 << 2;
}

/// See SpecifiedValueInfo::collect_completion_keywords.
pub type KeywordsCollectFn<'a> = &'a mut dyn FnMut(&[&'static str]);

/// Information of values of a given specified value type.
///
/// This trait is derivable with `#[derive(SpecifiedValueInfo)]`.
///
/// The algorithm traverses the type definition. For `SUPPORTED_TYPES`,
/// it puts an or'ed value of `SUPPORTED_TYPES` of all types it finds.
/// For `collect_completion_keywords`, it recursively invokes this
/// method on types found, and lists all keyword values and function
/// names following the same rule as `ToCss` in that method.
///
/// Some attributes of `ToCss` can affect the behavior, specifically:
/// * If `#[css(function)]` is found, the content inside the annotated
///   variant (or the whole type) isn't traversed, only the function
///   name is listed in `collect_completion_keywords`.
/// * If `#[css(skip)]` is found, the content inside the variant or
///   field is ignored.
/// * Values listed in `#[css(if_empty)]`, `#[parse(aliases)]`, and
///   `#[css(keyword)]` are added into `collect_completion_keywords`.
///
/// In addition to `css` attributes, it also has `value_info` helper
/// attributes, including:
/// * `#[value_info(ty = "TYPE")]` can be used to specify a constant
///   from `CssType` to `SUPPORTED_TYPES`.
/// * `#[value_info(other_values = "value1,value2")]` can be used to
///   add other values related to a field, variant, or the type itself
///   into `collect_completion_keywords`.
/// * `#[value_info(starts_with_keyword)]` can be used on variants to
///   add the name of a non-unit variant (serialized like `ToCss`) into
///   `collect_completion_keywords`.
pub trait SpecifiedValueInfo {
    /// Supported CssTypes by the given value type.
    ///
    /// XXX This should be typed CssType when that becomes a bitflags.
    /// Currently we cannot do so since bitflags cannot be used in constant.
    const SUPPORTED_TYPES: u8 = 0;

    /// Collect value starting words for the given specified value type.
    /// This includes keyword and function names which can appear at the
    /// beginning of a value of this type.
    ///
    /// Caller should pass in a callback function to accept the list of
    /// values. The callback function can be called multiple times, and
    /// some values passed to the callback may be duplicate.
    fn collect_completion_keywords(_f: KeywordsCollectFn) {}
}

impl SpecifiedValueInfo for bool {}
impl SpecifiedValueInfo for f32 {}
impl SpecifiedValueInfo for i8 {}
impl SpecifiedValueInfo for i32 {}
impl SpecifiedValueInfo for u8 {}
impl SpecifiedValueInfo for u16 {}
impl SpecifiedValueInfo for u32 {}
impl SpecifiedValueInfo for usize {}
impl SpecifiedValueInfo for str {}
impl SpecifiedValueInfo for String {}
impl SpecifiedValueInfo for crate::owned_str::OwnedStr {}

#[cfg(feature = "servo")]
impl SpecifiedValueInfo for ::servo_atoms::Atom {}
#[cfg(feature = "servo")]
impl SpecifiedValueInfo for ::servo_url::ServoUrl {}

impl<T: SpecifiedValueInfo + ?Sized> SpecifiedValueInfo for Box<T> {
    const SUPPORTED_TYPES: u8 = T::SUPPORTED_TYPES;
    fn collect_completion_keywords(f: KeywordsCollectFn) {
        T::collect_completion_keywords(f);
    }
}

impl<T: SpecifiedValueInfo> SpecifiedValueInfo for [T] {
    const SUPPORTED_TYPES: u8 = T::SUPPORTED_TYPES;
    fn collect_completion_keywords(f: KeywordsCollectFn) {
        T::collect_completion_keywords(f);
    }
}

macro_rules! impl_generic_specified_value_info {
    ($ty:ident<$param:ident>) => {
        impl<$param: SpecifiedValueInfo> SpecifiedValueInfo for $ty<$param> {
            const SUPPORTED_TYPES: u8 = $param::SUPPORTED_TYPES;
            fn collect_completion_keywords(f: KeywordsCollectFn) {
                $param::collect_completion_keywords(f);
            }
        }
    };
}
impl_generic_specified_value_info!(Option<T>);
impl_generic_specified_value_info!(OwnedSlice<T>);
impl_generic_specified_value_info!(Vec<T>);
impl_generic_specified_value_info!(Arc<T>);
impl_generic_specified_value_info!(StdArc<T>);
impl_generic_specified_value_info!(ArcSlice<T>);
impl_generic_specified_value_info!(Range<Idx>);

impl<T1, T2> SpecifiedValueInfo for (T1, T2)
where
    T1: SpecifiedValueInfo,
    T2: SpecifiedValueInfo,
{
    const SUPPORTED_TYPES: u8 = T1::SUPPORTED_TYPES | T2::SUPPORTED_TYPES;

    fn collect_completion_keywords(f: KeywordsCollectFn) {
        T1::collect_completion_keywords(f);
        T2::collect_completion_keywords(f);
    }
}