servo/components/script/init.rs

/* 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/. */

use js::jsapi::JSObject;

use crate::dom::bindings::codegen::RegisterBindings;
use crate::dom::bindings::conversions::is_dom_proxy;
use crate::dom::bindings::proxyhandler;
use crate::dom::bindings::utils::is_platform_object_static;
use crate::script_runtime::JSEngineSetup;

#[cfg(target_os = "linux")]
#[allow(unsafe_code)]
fn perform_platform_specific_initialization() {
    // 4096 is default max on many linux systems
    const MAX_FILE_LIMIT: libc::rlim_t = 4096;

    // Bump up our number of file descriptors to save us from impending doom caused by an onslaught
    // of iframes.
    unsafe {
        let mut rlim = libc::rlimit {
            rlim_cur: 0,
            rlim_max: 0,
        };
        match libc::getrlimit(libc::RLIMIT_NOFILE, &mut rlim) {
            0 => {
                if rlim.rlim_cur >= MAX_FILE_LIMIT {
                    // we have more than enough
                    return;
                }

                rlim.rlim_cur = match rlim.rlim_max {
                    libc::RLIM_INFINITY => MAX_FILE_LIMIT,
                    _ => {
                        if rlim.rlim_max < MAX_FILE_LIMIT {
                            rlim.rlim_max
                        } else {
                            MAX_FILE_LIMIT
                        }
                    },
                };
                match libc::setrlimit(libc::RLIMIT_NOFILE, &rlim) {
                    0 => (),
                    _ => warn!("Failed to set file count limit"),
                };
            },
            _ => warn!("Failed to get file count limit"),
        };
    }
}

#[cfg(not(target_os = "linux"))]
fn perform_platform_specific_initialization() {}

#[allow(unsafe_code)]
unsafe extern "C" fn is_dom_object(obj: *mut JSObject) -> bool {
    !obj.is_null() && (is_platform_object_static(obj) || is_dom_proxy(obj))
}

#[allow(unsafe_code)]
pub fn init() -> JSEngineSetup {
    unsafe {
        proxyhandler::init();

        // Create the global vtables used by the (generated) DOM
        // bindings to implement JS proxies.
        RegisterBindings::RegisterProxyHandlers();

        js::glue::InitializeMemoryReporter(Some(is_dom_object));
    }

    perform_platform_specific_initialization();

    JSEngineSetup::new()
}