servo_config/
prefs.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
5//! Preferences are the global configuration options that can be changed at runtime.
6
7use std::env::consts::ARCH;
8use std::sync::{RwLock, RwLockReadGuard};
9use std::time::Duration;
10
11use serde::{Deserialize, Serialize};
12use servo_config_macro::ServoPreferences;
13
14pub use crate::pref_util::PrefValue;
15
16static PREFERENCES: RwLock<Preferences> = RwLock::new(Preferences::const_default());
17
18/// A trait to be implemented by components that wish to be notified about runtime changes to the
19/// global preferences for the current process.
20pub trait PreferencesObserver: Send + Sync {
21    /// This method is called when the global preferences have been updated. The argument to the
22    /// method is an array of tuples where the first component is the name of the preference and
23    /// the second component is the new value of the preference.
24    fn prefs_changed(&self, _changes: &[(&'static str, PrefValue)]) {}
25}
26
27static OBSERVERS: RwLock<Vec<Box<dyn PreferencesObserver>>> = RwLock::new(Vec::new());
28
29#[inline]
30/// Get the current set of global preferences for Servo.
31pub fn get() -> RwLockReadGuard<'static, Preferences> {
32    PREFERENCES.read().unwrap()
33}
34
35/// Subscribe to notifications about changes to the global preferences for the current process.
36pub fn add_observer(observer: Box<dyn PreferencesObserver>) {
37    OBSERVERS.write().unwrap().push(observer);
38}
39
40/// Update the values of the global preferences for the current process. This also notifies the
41/// observers previously added using [`add_observer`].
42pub fn set(preferences: Preferences) {
43    // Get list of changes, returning early if the preferences haven't changed.
44    let changed = preferences.diff(&PREFERENCES.read().unwrap());
45    if changed.is_empty() {
46        return;
47    }
48
49    // Map between Stylo preference names and Servo preference names as the This should be
50    // kept in sync with components/script/dom/bindings/codegen/run.py which generates the
51    // DOM CSS style accessors.
52    stylo_static_prefs::set_pref!("layout.unimplemented", preferences.layout_unimplemented);
53    stylo_static_prefs::set_pref!("layout.threads", preferences.layout_threads as i32);
54    stylo_static_prefs::set_pref!("layout.columns.enabled", preferences.layout_columns_enabled);
55    stylo_static_prefs::set_pref!("layout.grid.enabled", preferences.layout_grid_enabled);
56    stylo_static_prefs::set_pref!(
57        "layout.css.alpha-color-function.enabled",
58        preferences.layout_css_alpha_color_function_enabled
59    );
60    stylo_static_prefs::set_pref!(
61        "layout.css.attr.enabled",
62        preferences.layout_css_attr_enabled
63    );
64    stylo_static_prefs::set_pref!(
65        "layout.css.ellipse-corners.enabled",
66        preferences.layout_css_ellipse_corners_enabled
67    );
68    stylo_static_prefs::set_pref!(
69        "layout.css.progress-function.enabled",
70        preferences.layout_css_progress_function_enabled
71    );
72    stylo_static_prefs::set_pref!(
73        "layout.writing-mode.enabled",
74        preferences.layout_writing_mode_enabled
75    );
76    stylo_static_prefs::set_pref!(
77        "layout.container-queries.enabled",
78        preferences.layout_container_queries_enabled
79    );
80    stylo_static_prefs::set_pref!(
81        "layout.variable_fonts.enabled",
82        preferences.layout_variable_fonts_enabled
83    );
84
85    *PREFERENCES.write().unwrap() = preferences;
86
87    for observer in &*OBSERVERS.read().unwrap() {
88        observer.prefs_changed(&changed);
89    }
90}
91
92/// A convenience macro for accessing a preference value using its static path.
93/// Passing an invalid path is a compile-time error.
94#[macro_export]
95macro_rules! pref {
96    ($name: ident) => {
97        $crate::prefs::get().$name.clone()
98    };
99}
100
101/// The set of global preferences supported by Servo.
102///
103/// Each preference has a default value that determines its initial state. These defaults
104/// fall into roughly three categories:
105/// - **Stable**: enabled by default.
106/// - **Experimental**: disabled by default, but intended to be enabled for experimental use.
107/// - **Unstable**: disabled by default.
108///
109/// For a full overview of which preferences are experimental, see the
110/// [experimental features documentation](https://book.servo.org/design-documentation/experimental-features.html).
111#[derive(Clone, Deserialize, Serialize, ServoPreferences)]
112pub struct Preferences {
113    pub fonts_default: String,
114    pub fonts_serif: String,
115    pub fonts_sans_serif: String,
116    pub fonts_monospace: String,
117    pub fonts_default_size: i64,
118    pub fonts_default_monospace_size: i64,
119    /// The amount of time that a half cycle of a text caret blink takes in milliseconds.
120    /// If this value is less than or equal to zero, then caret blink is disabled.
121    pub editing_caret_blink_time: i64,
122    pub css_animations_testing_enabled: bool,
123    /// Start the devtools server at startup
124    pub devtools_server_enabled: bool,
125    /// The address:port the devtools server listens to, default to 127.0.0.1:7000.
126    pub devtools_server_listen_address: String,
127    // feature: WebGPU | #24706 | Web/API/WebGPU_API
128    pub dom_webgpu_enabled: bool,
129    /// List of comma-separated backends to be used by wgpu.
130    pub dom_webgpu_wgpu_backend: String,
131    // feature: AbortController | #34866 | Web/API/AbortController
132    pub dom_abort_controller_enabled: bool,
133    // feature: Adopted Stylesheet | #38132 | Web/API/Document/adoptedStyleSheets
134    pub dom_adoptedstylesheet_enabled: bool,
135    pub dom_allow_preloading_module_descendants: bool,
136    // feature: Clipboard API | #36084 | Web/API/Clipboard_API
137    pub dom_async_clipboard_enabled: bool,
138    pub dom_bluetooth_enabled: bool,
139    pub dom_bluetooth_testing_enabled: bool,
140    pub dom_allow_scripts_to_close_windows: bool,
141    // feature: Media Capture and Streams API | #26861 | Web/API/Media_Capture_and_Streams_API
142    pub dom_canvas_capture_enabled: bool,
143    pub dom_canvas_text_enabled: bool,
144    /// Selects canvas backend
145    ///
146    /// Available values:
147    /// - vello
148    /// - Everything else selects vello_cpu
149    pub dom_canvas_backend: String,
150    /// Maximum number of buffered canvas commands before an automatic flush is triggered.
151    ///
152    /// A lower value keeps the paint thread fed with work (better parallelism),
153    /// while a higher value improves batching efficiency (fewer channel operations, lower power).
154    ///
155    /// See <https://github.com/servo/servo/pull/45301> for measurements.
156    pub dom_canvas_msg_buffer_size: u64,
157    pub dom_clipboardevent_enabled: bool,
158    pub dom_composition_event_enabled: bool,
159    // feature: CookieStore | #37674 | Web/API/CookieStore
160    pub dom_cookiestore_enabled: bool,
161    // feature: Credential Management API | #38788 | Web/API/Credential_Management_API
162    pub dom_credential_management_enabled: bool,
163    // feature: WebCrypto API | #40687 | Web/API/Web_Crypto_API
164    pub dom_crypto_subtle_enabled: bool,
165    pub dom_document_dblclick_timeout: i64,
166    pub dom_document_dblclick_dist: i64,
167    // feature: File and Directory Entries API | #45653 | Web/API/File_and_Directory_Entries_API
168    pub dom_entries_api_enabled: bool,
169    // feature: Document.execCommand | #25005 | Web/API/Document/execCommand
170    pub dom_exec_command_enabled: bool,
171    // feature: CSS Font Loading API | #29376 | Web/API/CSS_Font_Loading_API
172    pub dom_fontface_enabled: bool,
173    pub dom_fullscreen_test: bool,
174    // feature: Gamepad API | #10977 | Web/API/Gamepad_API
175    pub dom_gamepad_enabled: bool,
176    // feature: Geolocation API | #38903 | Web/API/Geolocation_API
177    pub dom_geolocation_enabled: bool,
178    // feature: Screen Wake Lock API | #43615 | Web/API/Screen_Wake_Lock_API
179    pub dom_wakelock_enabled: bool,
180    // feature: IndexedDB | #6963 | Web/API/IndexedDB_API
181    pub dom_indexeddb_enabled: bool,
182    // feature: IntersectionObserver | #35767 | Web/API/Intersection_Observer_API
183    pub dom_intersection_observer_enabled: bool,
184    pub dom_microdata_testing_enabled: bool,
185    pub dom_uievent_which_enabled: bool,
186    // feature: MutationObserver | #6633 | Web/API/MutationObserver
187    pub dom_mutation_observer_enabled: bool,
188    // feature: Navigator.registerProtocolHandler() | #40615 | Web/API/Navigator/registerProtocolHandler
189    pub dom_navigator_protocol_handlers_enabled: bool,
190    // feature: Notification API | #34841 | Web/API/Notifications_API
191    pub dom_notification_enabled: bool,
192    // feature: OffscreenCanvas | #34111 | Web/API/OffscreenCanvas
193    pub dom_offscreen_canvas_enabled: bool,
194    pub dom_parallel_css_parsing_enabled: bool,
195    // feature: Permissions API | #31235 | Web/API/Permissions_API
196    pub dom_permissions_enabled: bool,
197    pub dom_permissions_testing_allowed_in_nonsecure_contexts: bool,
198    // feature: ResizeObserver | #39790 | Web/API/ResizeObserver
199    pub dom_resize_observer_enabled: bool,
200    // feature: Sanitizer API | #43948 | Web/API/HTML_Sanitizer_API
201    pub dom_sanitizer_enabled: bool,
202    pub dom_script_asynch: bool,
203    // feature: Storage API | #43976 | Web/API/Storage_API
204    pub dom_storage_manager_api_enabled: bool,
205    // feature: ServiceWorker | #36538 | Web/API/Service_Worker_API
206    pub dom_serviceworker_enabled: bool,
207    pub dom_serviceworker_timeout_seconds: i64,
208    // feature: SharedWorker | #7458 | Web/API/SharedWorker
209    pub dom_sharedworker_enabled: bool,
210    pub dom_servo_helpers_enabled: bool,
211    pub dom_servoparser_async_html_tokenizer_enabled: bool,
212    pub dom_testbinding_enabled: bool,
213    pub dom_testbinding_prefcontrolled_enabled: bool,
214    pub dom_testbinding_prefcontrolled2_enabled: bool,
215    pub dom_testbinding_preference_value_falsy: bool,
216    pub dom_testbinding_preference_value_quote_string_test: String,
217    pub dom_testbinding_preference_value_space_string_test: String,
218    pub dom_testbinding_preference_value_string_empty: String,
219    pub dom_testbinding_preference_value_string_test: String,
220    pub dom_testbinding_preference_value_truthy: bool,
221    pub dom_testing_element_activation_enabled: bool,
222    pub dom_testing_html_input_element_select_files_enabled: bool,
223    pub dom_testperf_enabled: bool,
224    // https://testutils.spec.whatwg.org#availability
225    pub dom_testutils_enabled: bool,
226    /// <https://w3c.github.io/touch-events/#conditionally-exposing-legacy-touch-event-apis>
227    pub dom_touch_events_legacy_apis_enabled: bool,
228    /// <https://html.spec.whatwg.org/multipage/#transient-activation-duration>
229    pub dom_transient_activation_duration_ms: i64,
230    // feature: Web Animations | #36950 | Web/API/Web_Animations_API
231    pub dom_web_animations_enabled: bool,
232    /// Enable WebGL2 APIs.
233    // feature: WebGL2 | #41394 | Web/API/WebGL2RenderingContext
234    pub dom_webgl2_enabled: bool,
235    // feature: WebRTC | #41396 | Web/API/WebRTC_API
236    pub dom_webrtc_enabled: bool,
237    // feature: WebRTC Transceiver | #41396 | Web/API/RTCRtpTransceiver
238    pub dom_webrtc_transceiver_enabled: bool,
239    pub dom_webxr_enabled: bool,
240    pub dom_webxr_test: bool,
241    pub dom_webxr_first_person_observer_view: bool,
242    pub dom_webxr_glwindow_enabled: bool,
243    pub dom_webxr_glwindow_left_right: bool,
244    pub dom_webxr_glwindow_red_cyan: bool,
245    pub dom_webxr_glwindow_spherical: bool,
246    pub dom_webxr_glwindow_cubemap: bool,
247    pub dom_webxr_hands_enabled: bool,
248    // feature: WebXR Layers | #27468 | Web/API/XRCompositionLayer
249    pub dom_webxr_layers_enabled: bool,
250    pub dom_webxr_openxr_enabled: bool,
251    pub dom_webxr_sessionavailable: bool,
252    pub dom_webxr_unsafe_assume_user_intent: bool,
253    pub dom_worklet_enabled: bool,
254    pub dom_worklet_blockingsleep_enabled: bool,
255    pub dom_worklet_testing_enabled: bool,
256    pub dom_worklet_timeout_ms: i64,
257    /// <https://drafts.csswg.org/cssom-view/#the-visualviewport-interface>
258    // feature: VisualViewport | #41341 | Web/API/VisualViewport
259    pub dom_visual_viewport_enabled: bool,
260    /// True to compile all WebRender shaders when Servo initializes. This is mostly
261    /// useful when modifying the shaders, to ensure they all compile after each change is
262    /// made.
263    pub gfx_precache_shaders: bool,
264    /// Whether or not antialiasing is enabled for text rendering.
265    pub gfx_text_antialiasing_enabled: bool,
266    /// Whether or not subpixel antialiasing is enabled for text rendering.
267    pub gfx_subpixel_text_antialiasing_enabled: bool,
268    pub gfx_texture_swizzling_enabled: bool,
269    /// The amount of image keys we request per batch for the image cache.
270    pub image_key_batch_size: i64,
271    /// Whether or not the DOM inspector should show shadow roots of user-agent shadow trees
272    pub inspector_show_servo_internal_shadow_roots: bool,
273    /// A locale tag (eg. es-ES) to use for language negotiation instead of the system locale.
274    /// An empty string represents no override.
275    /// TODO: Option<> support in PrefValue
276    pub intl_locale_override: String,
277    pub js_asmjs_enabled: bool,
278    pub js_baseline_interpreter_enabled: bool,
279    /// Whether to disable the jit within SpiderMonkey
280    pub js_disable_jit: bool,
281    pub js_baseline_jit_enabled: bool,
282    pub js_baseline_jit_unsafe_eager_compilation_enabled: bool,
283    pub js_ion_enabled: bool,
284    pub js_ion_unsafe_eager_compilation_enabled: bool,
285    pub js_mem_gc_compacting_enabled: bool,
286    pub js_mem_gc_empty_chunk_count_min: i64,
287    pub js_mem_gc_high_frequency_heap_growth_max: i64,
288    pub js_mem_gc_high_frequency_heap_growth_min: i64,
289    pub js_mem_gc_high_frequency_high_limit_mb: i64,
290    pub js_mem_gc_high_frequency_low_limit_mb: i64,
291    pub js_mem_gc_high_frequency_time_limit_ms: i64,
292    /// Whether or not incremental garbage collection is turned on. This is currently
293    /// turned off by default as pre-barriers are not implemented yet. If turned on, it
294    /// will likely lead to memory corruption.
295    ///
296    /// See <https://github.com/servo/servo/issues/7621>.
297    pub js_mem_gc_incremental_enabled: bool,
298    pub js_mem_gc_incremental_slice_ms: i64,
299    pub js_mem_gc_low_frequency_heap_growth: i64,
300    pub js_mem_gc_per_zone_enabled: bool,
301    pub js_mem_gc_zeal_frequency: i64,
302    pub js_mem_gc_zeal_level: i64,
303    pub js_mem_max: i64,
304    pub js_native_regex_enabled: bool,
305    pub js_offthread_compilation_enabled: bool,
306    pub js_timers_minimum_duration: i64,
307    pub js_wasm_baseline_enabled: bool,
308    pub js_wasm_enabled: bool,
309    pub js_wasm_ion_enabled: bool,
310    // feature: Largest Contentful Paint | #42000 | Web/API/LargestContentfulPaint
311    pub largest_contentful_paint_enabled: bool,
312    pub layout_animations_test_enabled: bool,
313    // feature: CSS Multicol | #22397 | Web/CSS/Guides/Multicol_layout
314    pub layout_columns_enabled: bool,
315    // feature: CSS Grid | #34479 | Web/CSS/Guides/Grid_layout
316    pub layout_grid_enabled: bool,
317    pub layout_container_queries_enabled: bool,
318    pub layout_css_alpha_color_function_enabled: bool,
319    pub layout_css_attr_enabled: bool,
320    pub layout_css_ellipse_corners_enabled: bool,
321    pub layout_css_progress_function_enabled: bool,
322    pub layout_style_sharing_cache_enabled: bool,
323    pub layout_threads: i64,
324    /// The minimum number of parallelizable jobs required before turning on parallelism
325    /// for a set of jobs.
326    ///
327    /// When deciding whether or not to parallelize layout, this is the minimum number of
328    /// jobs that must be larger than [`Self::layout_parallelism_job_size_minimum`] to
329    /// turn on parallelism. An exception is when doing box tree layout, where Servo does
330    /// not know the depth of the tree. In that case any task that has more jobs than this
331    /// value will be parallelized.
332    ///
333    /// The goal of these two values is to allow tuning Servo's parallelism for both wide
334    /// and deep trees.
335    pub layout_parallelism_job_count_minimum: u64,
336    /// The minimum size of a layout job to be considered for parallelization.
337    ///
338    /// When deciding whether or not to parallelize layout, jobs greater than this size
339    /// are counted when considering the [`Self::layout_parallelism_job_count_minimum`]
340    /// threshold for turning on parallelism. Generally the size of the job is based on
341    /// the number of tasks to process in the subtree. For instance, this might be the
342    /// number of boxes to process in a box tree subtree.
343    ///
344    /// The goal of these two values is to allow tuning Servo's parallelism for both wide
345    /// and deep trees.
346    pub layout_parallelism_job_size_minimum: u64,
347    pub layout_unimplemented: bool,
348    // feature: Variable fonts | #38800 | Web/CSS/Guides/Fonts/Variable_fonts
349    pub layout_variable_fonts_enabled: bool,
350    // feature: CSS writing modes | #2560 | Web/CSS/Guides/Writing_modes
351    pub layout_writing_mode_enabled: bool,
352    /// Enable hardware acceleration for video playback.
353    pub media_glvideo_enabled: bool,
354    /// Enable a non-standard event handler for verifying behavior of media elements during tests.
355    pub media_testing_enabled: bool,
356    /// The default timeout set for establishing a network connection in seconds. This amount
357    /// if for the entire process of connecting to an address. For instance, if a particular host is
358    /// associated with multiple IP addresses, this timeout will be divided equally among
359    /// each IP address.
360    pub network_connection_timeout: u64,
361    pub network_enforce_tls_enabled: bool,
362    pub network_enforce_tls_localhost: bool,
363    pub network_enforce_tls_onion: bool,
364    pub network_http_cache_disabled: bool,
365    /// A url for a http proxy. We treat an empty string as no proxy.
366    pub network_http_proxy_uri: String,
367    /// A url for a https proxy. We treat an empty string as no proxy.
368    pub network_https_proxy_uri: String,
369    /// The domains for which we will not have a proxy. No effect if `network_http_proxy_uri` is not set.
370    /// The exact behavior is given by
371    /// <https://docs.rs/hyper-util/latest/hyper_util/client/proxy/matcher/struct.Builder.html#method.no>
372    pub network_http_no_proxy: String,
373    /// The weight of the http memory cache
374    /// Notice that this is not equal to the number of different urls in the cache.
375    pub network_http_cache_size: u64,
376    pub network_local_directory_listing_enabled: bool,
377    /// Force the use of `rust-webpki` verification for CA roots. If this is false (the
378    /// default), then `rustls-platform-verifier` will be used, except on Android where
379    /// `rust-webpki` is always used.
380    pub network_use_webpki_roots: bool,
381    /// The maximum content size we will forward for preallocation, defaults to 5MB
382    pub network_max_content_length: u64,
383    /// The length of the session history, in navigations, for each `WebView. Back-forward
384    /// cache entries that are more than `session_history_max_length` steps in the future or
385    /// `session_history_max_length` steps in the past will be discarded. Navigating forward
386    /// or backward to that entry will cause the entire page to be reloaded.
387    pub session_history_max_length: i64,
388    /// The background color of shell's viewport. This will be used by OpenGL's `glClearColor`.
389    pub shell_background_color_rgba: [f64; 4],
390    pub webgl_testing_context_creation_error: bool,
391    /// Maximum number of workers for the main thread pool
392    pub thread_pool_workers_max: u64,
393    /// Number of workers per thread pool, if we fail to detect how much
394    /// parallelism is available at runtime.
395    pub thread_pool_fallback_workers: u64,
396    /// Maximum number of workers for the asynchronous networking runtime thread pool
397    pub thread_pool_async_runtime_workers_max: u64,
398    /// Maximum number of workers for WebRender
399    pub thread_pool_webrender_workers_max: u64,
400    /// The user-agent to use for Servo. This can also be set via [`UserAgentPlatform`] in
401    /// order to set the value to the default value for the given platform.
402    pub user_agent: String,
403    /// Whether or not the viewport meta tag is enabled.
404    pub viewport_meta_enabled: bool,
405    pub log_filter: String,
406    /// Whether the accessibility code is enabled.
407    pub accessibility_enabled: bool,
408    /// Whether to run accessibility tree integrity checks, and any other expensive checks.
409    /// This should only be true in tests.
410    pub expensive_accessibility_test_assertions_enabled: bool,
411    /// Exposes internal JS API functions that are usually restricted to `about:...` pages
412    /// Useful if you want to get memory report or force GC in a test page
413    pub expose_servointernals_globally: bool,
414}
415
416impl Preferences {
417    const fn const_default() -> Self {
418        Self {
419            css_animations_testing_enabled: false,
420            editing_caret_blink_time: 600,
421            devtools_server_enabled: false,
422            devtools_server_listen_address: String::new(),
423            dom_abort_controller_enabled: true,
424            dom_adoptedstylesheet_enabled: false,
425            dom_allow_preloading_module_descendants: false,
426            dom_allow_scripts_to_close_windows: false,
427            dom_async_clipboard_enabled: false,
428            dom_bluetooth_enabled: false,
429            dom_bluetooth_testing_enabled: false,
430            dom_canvas_capture_enabled: false,
431            dom_canvas_text_enabled: true,
432            dom_canvas_backend: String::new(),
433            dom_canvas_msg_buffer_size: 16,
434            dom_clipboardevent_enabled: true,
435            dom_composition_event_enabled: false,
436            dom_cookiestore_enabled: false,
437            dom_credential_management_enabled: false,
438            dom_crypto_subtle_enabled: true,
439            dom_document_dblclick_dist: 1,
440            dom_document_dblclick_timeout: 300,
441            dom_entries_api_enabled: false,
442            dom_exec_command_enabled: false,
443            dom_fontface_enabled: false,
444            dom_fullscreen_test: false,
445            dom_gamepad_enabled: true,
446            dom_geolocation_enabled: false,
447            dom_wakelock_enabled: false,
448            dom_indexeddb_enabled: false,
449            dom_intersection_observer_enabled: false,
450            dom_microdata_testing_enabled: false,
451            dom_uievent_which_enabled: true,
452            dom_mutation_observer_enabled: true,
453            dom_navigator_protocol_handlers_enabled: false,
454            dom_notification_enabled: false,
455            dom_parallel_css_parsing_enabled: true,
456            dom_offscreen_canvas_enabled: false,
457            dom_permissions_enabled: false,
458            dom_permissions_testing_allowed_in_nonsecure_contexts: false,
459            dom_resize_observer_enabled: true,
460            dom_sanitizer_enabled: false,
461            dom_script_asynch: true,
462            dom_storage_manager_api_enabled: false,
463            dom_serviceworker_enabled: false,
464            dom_serviceworker_timeout_seconds: 60,
465            dom_sharedworker_enabled: true,
466            dom_servo_helpers_enabled: false,
467            dom_servoparser_async_html_tokenizer_enabled: false,
468            dom_testbinding_enabled: false,
469            dom_testbinding_prefcontrolled2_enabled: false,
470            dom_testbinding_prefcontrolled_enabled: false,
471            dom_testbinding_preference_value_falsy: false,
472            dom_testbinding_preference_value_quote_string_test: String::new(),
473            dom_testbinding_preference_value_space_string_test: String::new(),
474            dom_testbinding_preference_value_string_empty: String::new(),
475            dom_testbinding_preference_value_string_test: String::new(),
476            dom_testbinding_preference_value_truthy: false,
477            dom_testing_element_activation_enabled: false,
478            dom_testing_html_input_element_select_files_enabled: false,
479            dom_testperf_enabled: false,
480            dom_testutils_enabled: false,
481            // Following Firefox and Chrome, we are enabling the touch events legacy APIs for android.
482            // Additionally, enabling it in ohos for compatibility as well.
483            dom_touch_events_legacy_apis_enabled: cfg!(target_os = "android") |
484                cfg!(target_env = "ohos"),
485            dom_transient_activation_duration_ms: 5000,
486            dom_web_animations_enabled: false,
487            dom_webgl2_enabled: false,
488            dom_webgpu_enabled: false,
489            dom_webgpu_wgpu_backend: String::new(),
490            dom_webrtc_enabled: false,
491            dom_webrtc_transceiver_enabled: false,
492            dom_webxr_enabled: true,
493            dom_webxr_first_person_observer_view: false,
494            dom_webxr_glwindow_cubemap: false,
495            dom_webxr_glwindow_enabled: true,
496            dom_webxr_glwindow_left_right: false,
497            dom_webxr_glwindow_red_cyan: false,
498            dom_webxr_glwindow_spherical: false,
499            dom_webxr_hands_enabled: true,
500            dom_webxr_layers_enabled: false,
501            dom_webxr_openxr_enabled: true,
502            dom_webxr_sessionavailable: false,
503            dom_webxr_test: false,
504            dom_webxr_unsafe_assume_user_intent: false,
505            dom_worklet_blockingsleep_enabled: false,
506            dom_worklet_enabled: false,
507            dom_worklet_testing_enabled: false,
508            dom_worklet_timeout_ms: 10,
509            dom_visual_viewport_enabled: false,
510            accessibility_enabled: false,
511            expensive_accessibility_test_assertions_enabled: false,
512            fonts_default: String::new(),
513            fonts_default_monospace_size: 13,
514            fonts_default_size: 16,
515            fonts_monospace: String::new(),
516            fonts_sans_serif: String::new(),
517            fonts_serif: String::new(),
518            gfx_precache_shaders: false,
519            gfx_text_antialiasing_enabled: true,
520            gfx_subpixel_text_antialiasing_enabled: true,
521            gfx_texture_swizzling_enabled: true,
522            image_key_batch_size: 10,
523            inspector_show_servo_internal_shadow_roots: false,
524            intl_locale_override: String::new(),
525            js_asmjs_enabled: true,
526            js_baseline_interpreter_enabled: true,
527            js_baseline_jit_enabled: true,
528            js_baseline_jit_unsafe_eager_compilation_enabled: false,
529            js_disable_jit: false,
530            js_ion_enabled: true,
531            js_ion_unsafe_eager_compilation_enabled: false,
532            js_mem_gc_compacting_enabled: true,
533            js_mem_gc_empty_chunk_count_min: 1,
534            js_mem_gc_high_frequency_heap_growth_max: 300,
535            js_mem_gc_high_frequency_heap_growth_min: 150,
536            js_mem_gc_high_frequency_high_limit_mb: 500,
537            js_mem_gc_high_frequency_low_limit_mb: 100,
538            js_mem_gc_high_frequency_time_limit_ms: 1000,
539            js_mem_gc_incremental_enabled: false,
540            js_mem_gc_incremental_slice_ms: 10,
541            js_mem_gc_low_frequency_heap_growth: 150,
542            js_mem_gc_per_zone_enabled: false,
543            js_mem_gc_zeal_frequency: 100,
544            js_mem_gc_zeal_level: 0,
545            js_mem_max: -1,
546            js_native_regex_enabled: true,
547            js_offthread_compilation_enabled: true,
548            js_timers_minimum_duration: 1000,
549            js_wasm_baseline_enabled: true,
550            js_wasm_enabled: true,
551            js_wasm_ion_enabled: true,
552            largest_contentful_paint_enabled: false,
553            layout_animations_test_enabled: false,
554            layout_columns_enabled: false,
555            layout_container_queries_enabled: false,
556            layout_css_alpha_color_function_enabled: false,
557            layout_css_attr_enabled: false,
558            layout_css_ellipse_corners_enabled: false,
559            layout_css_progress_function_enabled: false,
560            layout_grid_enabled: false,
561            layout_style_sharing_cache_enabled: true,
562            // TODO(mrobinson): This should likely be based on the number of processors.
563            layout_threads: 3,
564            layout_parallelism_job_count_minimum: 4,
565            layout_parallelism_job_size_minimum: 16,
566            layout_unimplemented: false,
567            layout_variable_fonts_enabled: false,
568            layout_writing_mode_enabled: false,
569            media_glvideo_enabled: false,
570            media_testing_enabled: false,
571            network_connection_timeout: 15,
572            network_enforce_tls_enabled: false,
573            network_enforce_tls_localhost: false,
574            network_enforce_tls_onion: false,
575            network_http_cache_disabled: false,
576            network_http_proxy_uri: String::new(),
577            network_https_proxy_uri: String::new(),
578            network_http_no_proxy: String::new(),
579            network_http_cache_size: 5000,
580            network_local_directory_listing_enabled: true,
581            network_use_webpki_roots: false,
582            network_max_content_length: 5 * 1024 * 1024,
583            session_history_max_length: 20,
584            shell_background_color_rgba: [1.0, 1.0, 1.0, 1.0],
585            log_filter: String::new(),
586            thread_pool_workers_max: 4,
587            thread_pool_async_runtime_workers_max: 6,
588            thread_pool_fallback_workers: 3,
589            thread_pool_webrender_workers_max: 4,
590            webgl_testing_context_creation_error: false,
591            user_agent: String::new(),
592            viewport_meta_enabled: false,
593            expose_servointernals_globally: false,
594        }
595    }
596
597    /// The amount of time that a half cycle of a text caret blink takes. If blinking is disabled
598    /// this returns `None`.
599    pub fn editing_caret_blink_time(&self) -> Option<Duration> {
600        if self.editing_caret_blink_time > 0 {
601            Some(Duration::from_millis(self.editing_caret_blink_time as u64))
602        } else {
603            None
604        }
605    }
606}
607
608impl Default for Preferences {
609    fn default() -> Self {
610        let mut preferences = Self::const_default();
611        preferences.user_agent = UserAgentPlatform::default().to_user_agent_string();
612        if let Ok(proxy_uri) = std::env::var("http_proxy").or_else(|_| std::env::var("HTTP_PROXY"))
613        {
614            preferences.network_http_proxy_uri = proxy_uri;
615        }
616        if let Ok(proxy_uri) =
617            std::env::var("https_proxy").or_else(|_| std::env::var("HTTPS_PROXY"))
618        {
619            preferences.network_https_proxy_uri = proxy_uri;
620        }
621        if let Ok(no_proxy) = std::env::var("no_proxy").or_else(|_| std::env::var("NO_PROXY")) {
622            preferences.network_http_no_proxy = no_proxy
623        }
624
625        preferences
626    }
627}
628
629pub enum UserAgentPlatform {
630    Desktop,
631    Android,
632    OpenHarmony,
633    Ios,
634}
635
636impl UserAgentPlatform {
637    /// Return the default `UserAgentPlatform` for this platform. This is
638    /// not an implementation of `Default` so that it can be `const`.
639    pub const fn default() -> Self {
640        if cfg!(target_os = "android") {
641            Self::Android
642        } else if cfg!(target_env = "ohos") {
643            Self::OpenHarmony
644        } else if cfg!(target_os = "ios") {
645            Self::Ios
646        } else {
647            Self::Desktop
648        }
649    }
650}
651
652impl UserAgentPlatform {
653    /// Convert this [`UserAgentPlatform`] into its corresponding `String` value, ie the
654    /// default user-agent to use for this platform.
655    pub fn to_user_agent_string(&self) -> String {
656        const SERVO_VERSION: &str = env!("CARGO_PKG_VERSION");
657        match self {
658            UserAgentPlatform::Desktop
659                if cfg!(all(target_os = "windows", target_arch = "x86_64")) =>
660            {
661                format!(
662                    "Mozilla/5.0 (Windows NT 10.0; Win64; {ARCH}rv:140.0) Servo/{SERVO_VERSION} Firefox/140.0"
663                )
664            },
665            UserAgentPlatform::Desktop if cfg!(target_os = "macos") => {
666                format!(
667                    "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:140.0) Servo/{SERVO_VERSION} Firefox/140.0"
668                )
669            },
670            UserAgentPlatform::Desktop => {
671                format!(
672                    "Mozilla/5.0 (X11; Linux {ARCH}; rv:140.0) Servo/{SERVO_VERSION} Firefox/140.0"
673                )
674            },
675            UserAgentPlatform::Android => {
676                format!(
677                    "Mozilla/5.0 (Android 10; Mobile; rv:140.0) Servo/{SERVO_VERSION} Firefox/140.0"
678                )
679            },
680            UserAgentPlatform::OpenHarmony => format!(
681                "Mozilla/5.0 (OpenHarmony; Mobile; rv:140.0) Servo/{SERVO_VERSION} Firefox/140.0"
682            ),
683            UserAgentPlatform::Ios => format!(
684                "Mozilla/5.0 (iPhone; CPU iPhone OS 18_6 like Mac OS X; rv:140.0) Servo/{SERVO_VERSION} Firefox/140.0"
685            ),
686        }
687    }
688}
servo_config/prefs.rs

servo_config/
prefs.rs
