servo/
javascript_evaluator.rs

1/* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
4
5use std::collections::HashMap;
6
7use base::id::WebViewId;
8use constellation_traits::EmbedderToConstellationMessage;
9use embedder_traits::{JSValue, JavaScriptEvaluationError, JavaScriptEvaluationId};
10
11use crate::ConstellationProxy;
12
13struct PendingEvaluation {
14    callback: Box<dyn FnOnce(Result<JSValue, JavaScriptEvaluationError>)>,
15}
16
17pub(crate) struct JavaScriptEvaluator {
18    current_id: JavaScriptEvaluationId,
19    constellation_proxy: ConstellationProxy,
20    pending_evaluations: HashMap<JavaScriptEvaluationId, PendingEvaluation>,
21}
22
23impl JavaScriptEvaluator {
24    pub(crate) fn new(constellation_proxy: ConstellationProxy) -> Self {
25        Self {
26            current_id: JavaScriptEvaluationId(0),
27            constellation_proxy,
28            pending_evaluations: Default::default(),
29        }
30    }
31
32    fn generate_id(&mut self) -> JavaScriptEvaluationId {
33        let next_id = JavaScriptEvaluationId(self.current_id.0 + 1);
34        std::mem::replace(&mut self.current_id, next_id)
35    }
36
37    pub(crate) fn evaluate(
38        &mut self,
39        webview_id: WebViewId,
40        script: String,
41        callback: Box<dyn FnOnce(Result<JSValue, JavaScriptEvaluationError>)>,
42    ) {
43        let evaluation_id = self.generate_id();
44        self.constellation_proxy
45            .send(EmbedderToConstellationMessage::EvaluateJavaScript(
46                webview_id,
47                evaluation_id,
48                script,
49            ));
50        self.pending_evaluations
51            .insert(evaluation_id, PendingEvaluation { callback });
52    }
53
54    pub(crate) fn finish_evaluation(
55        &mut self,
56        evaluation_id: JavaScriptEvaluationId,
57        result: Result<JSValue, JavaScriptEvaluationError>,
58    ) {
59        (self
60            .pending_evaluations
61            .remove(&evaluation_id)
62            .expect("Received request to finish unknown JavaScript evaluation.")
63            .callback)(result)
64    }
65}
servo/javascript_evaluator.rs

servo/
javascript_evaluator.rs
