tauri-runtime-servocat 0.5.0

Servo-replacement runtime for Tauri: wires html-cat, css-cat, dom-cat, layout-cat, paint-cat, net-cat, boa-cat, ecma-runtime-cat, and web-api-cat into a single rendering + scripting pipeline. v0.5.0 adds an IPC bridge so JS scripts can call host commands via `__TAURI__.invoke(cmd, ...args)`, and back-propagates scripted DOM mutations into layout via `web_api_cat::extract_document`. tauri_runtime::Runtime trait impl is the remaining committed deliverable. The Servo no-AI policy disqualifies upstream contribution; this is the AI-built parallel.
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

//! v0.5 integration tests: host command invocation + DOM back-prop.

use boa_cat::Value;
use boa_cat::fuel::Fuel;
use boa_cat::heap::Heap;
use boa_cat::outcome::{EvalResult, Outcome};
use paint_cat::PaintCommand;
use tauri_runtime_servocat::{
    Error, HostCommands, Viewport, run_script_with_backprop, run_script_with_commands,
};

fn fail(_msg: &'static str) -> Error {
    Error::Engine(boa_cat::Error::Unsupported { feature: "test" })
}

#[allow(clippy::needless_pass_by_value, clippy::unnecessary_wraps)]
fn echo_upper(args: Vec<Value>, _this: Value, heap: Heap, fuel: Fuel) -> EvalResult {
    let text = args
        .first()
        .and_then(|first| match first {
            Value::String(s) => Some(s.clone()),
            Value::Undefined
            | Value::Null
            | Value::Boolean(_)
            | Value::Number(_)
            | Value::Object(_)
            | Value::Function(_)
            | Value::Native(_) => None,
        })
        .unwrap_or_default();
    let upper = text.to_uppercase();
    Ok((Outcome::Normal(Value::String(upper)), heap, fuel))
}

#[allow(clippy::needless_pass_by_value, clippy::unnecessary_wraps)]
fn add(args: Vec<Value>, _this: Value, heap: Heap, fuel: Fuel) -> EvalResult {
    let total: f64 = args
        .iter()
        .filter_map(|value| match value {
            Value::Number(n) => Some(*n),
            Value::Undefined
            | Value::Null
            | Value::Boolean(_)
            | Value::String(_)
            | Value::Object(_)
            | Value::Function(_)
            | Value::Native(_) => None,
        })
        .sum();
    Ok((Outcome::Normal(Value::Number(total)), heap, fuel))
}

#[test]
fn host_command_invoked_via_dispatcher() -> Result<(), Error> {
    let commands = HostCommands::new().with("shout", echo_upper);
    let frame = run_script_with_commands(
        "<html><body></body></html>",
        "",
        "__TAURI__.invoke('shout', 'hello')",
        Viewport::new(100, 100),
        &commands,
    )?;
    matches!(frame.script_value(), Value::String(s) if s == "HELLO")
        .then_some(())
        .ok_or_else(|| fail("expected 'HELLO' from __TAURI__.invoke"))
}

#[test]
fn host_command_invoked_as_method() -> Result<(), Error> {
    let commands = HostCommands::new().with("shout", echo_upper);
    let frame = run_script_with_commands(
        "<html><body></body></html>",
        "",
        "__TAURI__.shout('hi there')",
        Viewport::new(100, 100),
        &commands,
    )?;
    matches!(frame.script_value(), Value::String(s) if s == "HI THERE")
        .then_some(())
        .ok_or_else(|| fail("expected 'HI THERE' from __TAURI__.shout"))
}

#[test]
fn host_command_with_multiple_args() -> Result<(), Error> {
    let commands = HostCommands::new().with("add", add);
    let frame = run_script_with_commands(
        "<html><body></body></html>",
        "",
        "__TAURI__.invoke('add', 1, 2, 3, 4)",
        Viewport::new(100, 100),
        &commands,
    )?;
    matches!(frame.script_value(), Value::Number(n) if (*n - 10.0).abs() < 1e-9)
        .then_some(())
        .ok_or_else(|| fail("expected 10 from add(1,2,3,4)"))
}

#[test]
fn unknown_command_returns_null() -> Result<(), Error> {
    let commands = HostCommands::new();
    let frame = run_script_with_commands(
        "<html><body></body></html>",
        "",
        "__TAURI__.invoke('nope', 'x')",
        Viewport::new(100, 100),
        &commands,
    )?;
    matches!(frame.script_value(), Value::Null)
        .then_some(())
        .ok_or_else(|| fail("expected null for unknown command"))
}

#[test]
fn backprop_picks_up_set_attribute_class_change() -> Result<(), Error> {
    let frame = run_script_with_backprop(
        "<html><body><p id='p'>hello</p></body></html>",
        "p { background-color: red; height: 30px; } p.live { background-color: green; }",
        "document.getElementById('p').setAttribute('class', 'live')",
        Viewport::new(200, 100),
        &HostCommands::new(),
    )?;
    let has_green = frame.display_list().commands().iter().any(|cmd| match cmd {
        PaintCommand::FillRect { color, .. } => {
            (color.green() - 0.5).abs() < 0.5
                && color.red() < 0.1
                && color.blue() < 0.1
                && color.green() > 0.4
        }
        PaintCommand::StrokeRect { .. } | PaintCommand::FillText { .. } => false,
    });
    has_green
        .then_some(())
        .ok_or_else(|| fail("expected a green FillRect after class mutation back-prop"))
}

#[test]
fn backprop_falls_back_when_no_mutation() -> Result<(), Error> {
    let frame_no_script = run_script_with_backprop(
        "<html><body><p>hi</p></body></html>",
        "p { background-color: red; height: 20px; }",
        "1",
        Viewport::new(100, 50),
        &HostCommands::new(),
    )?;
    (!frame_no_script.display_list().is_empty())
        .then_some(())
        .ok_or_else(|| fail("expected non-empty display list with no-op script"))
}