servo/components/script/dom/globalscope.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 http://mozilla.org/MPL/2.0/. */

use devtools_traits::{ScriptToDevtoolsControlMsg, WorkerId};
use dom::bindings::cell::DOMRefCell;
use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
use dom::bindings::error::{ErrorInfo, report_pending_exception};
use dom::bindings::inheritance::Castable;
use dom::bindings::js::{JS, MutNullableHeap, Root};
use dom::bindings::reflector::Reflectable;
use dom::bindings::str::DOMString;
use dom::crypto::Crypto;
use dom::dedicatedworkerglobalscope::DedicatedWorkerGlobalScope;
use dom::errorevent::ErrorEvent;
use dom::event::{Event, EventBubbles, EventCancelable};
use dom::eventdispatcher::EventStatus;
use dom::eventtarget::EventTarget;
use dom::window::Window;
use dom::workerglobalscope::WorkerGlobalScope;
use ipc_channel::ipc::IpcSender;
use js::jsapi::{HandleValue, Evaluate2, JS_GetContext, JS_GetObjectRuntime};
use js::jsapi::{JSAutoCompartment, JSContext, MutableHandleValue};
use js::rust::CompileOptionsWrapper;
use libc;
use msg::constellation_msg::PipelineId;
use net_traits::{CoreResourceThread, ResourceThreads, IpcSend};
use profile_traits::{mem, time};
use script_runtime::{EnqueuedPromiseCallback, ScriptChan};
use script_runtime::{ScriptPort, maybe_take_panic_result};
use script_thread::{MainThreadScriptChan, RunnableWrapper, ScriptThread};
use script_traits::{MsDuration, ScriptMsg as ConstellationMsg, TimerEvent};
use script_traits::{TimerEventId, TimerEventRequest, TimerSource};
use std::cell::Cell;
use std::collections::HashMap;
use std::collections::hash_map::Entry;
use std::ffi::CString;
use std::panic;
use time::{Timespec, get_time};
use timers::{IsInterval, OneshotTimerCallback, OneshotTimerHandle};
use timers::{OneshotTimers, TimerCallback};
use url::Url;

#[dom_struct]
pub struct GlobalScope {
    eventtarget: EventTarget,
    crypto: MutNullableHeap<JS<Crypto>>,
    next_worker_id: Cell<WorkerId>,

    /// Pipeline id associated with this global.
    pipeline_id: PipelineId,

    /// A flag to indicate whether the developer tools has requested
    /// live updates from the worker.
    devtools_wants_updates: Cell<bool>,

    /// Timers used by the Console API.
    console_timers: DOMRefCell<HashMap<DOMString, u64>>,

    /// For providing instructions to an optional devtools server.
    #[ignore_heap_size_of = "channels are hard"]
    devtools_chan: Option<IpcSender<ScriptToDevtoolsControlMsg>>,

    /// For sending messages to the memory profiler.
    #[ignore_heap_size_of = "channels are hard"]
    mem_profiler_chan: mem::ProfilerChan,

    /// For sending messages to the time profiler.
    #[ignore_heap_size_of = "channels are hard"]
    time_profiler_chan: time::ProfilerChan,

    /// A handle for communicating messages to the constellation thread.
    #[ignore_heap_size_of = "channels are hard"]
    constellation_chan: IpcSender<ConstellationMsg>,

    #[ignore_heap_size_of = "channels are hard"]
    scheduler_chan: IpcSender<TimerEventRequest>,

    /// https://html.spec.whatwg.org/multipage/#in-error-reporting-mode
    in_error_reporting_mode: Cell<bool>,

    /// Associated resource threads for use by DOM objects like XMLHttpRequest,
    /// including resource_thread, filemanager_thread and storage_thread
    resource_threads: ResourceThreads,

    timers: OneshotTimers,
}

impl GlobalScope {
    pub fn new_inherited(
            pipeline_id: PipelineId,
            devtools_chan: Option<IpcSender<ScriptToDevtoolsControlMsg>>,
            mem_profiler_chan: mem::ProfilerChan,
            time_profiler_chan: time::ProfilerChan,
            constellation_chan: IpcSender<ConstellationMsg>,
            scheduler_chan: IpcSender<TimerEventRequest>,
            resource_threads: ResourceThreads,
            timer_event_chan: IpcSender<TimerEvent>)
            -> Self {
        GlobalScope {
            eventtarget: EventTarget::new_inherited(),
            crypto: Default::default(),
            next_worker_id: Cell::new(WorkerId(0)),
            pipeline_id: pipeline_id,
            devtools_wants_updates: Default::default(),
            console_timers: DOMRefCell::new(Default::default()),
            devtools_chan: devtools_chan,
            mem_profiler_chan: mem_profiler_chan,
            time_profiler_chan: time_profiler_chan,
            constellation_chan: constellation_chan,
            scheduler_chan: scheduler_chan.clone(),
            in_error_reporting_mode: Default::default(),
            resource_threads: resource_threads,
            timers: OneshotTimers::new(timer_event_chan, scheduler_chan),
        }
    }

    #[allow(unsafe_code)]
    pub fn get_cx(&self) -> *mut JSContext {
        unsafe {
            let runtime = JS_GetObjectRuntime(
                self.reflector().get_jsobject().get());
            assert!(!runtime.is_null());
            let context = JS_GetContext(runtime);
            assert!(!context.is_null());
            context
        }
    }

    pub fn crypto(&self) -> Root<Crypto> {
        self.crypto.or_init(|| Crypto::new(self))
    }

    /// Get next worker id.
    pub fn get_next_worker_id(&self) -> WorkerId {
        let worker_id = self.next_worker_id.get();
        let WorkerId(id_num) = worker_id;
        self.next_worker_id.set(WorkerId(id_num + 1));
        worker_id
    }

    pub fn live_devtools_updates(&self) -> bool {
        self.devtools_wants_updates.get()
    }

    pub fn set_devtools_wants_updates(&self, value: bool) {
        self.devtools_wants_updates.set(value);
    }

    pub fn time(&self, label: DOMString) -> Result<(), ()> {
        let mut timers = self.console_timers.borrow_mut();
        if timers.len() >= 10000 {
            return Err(());
        }
        match timers.entry(label) {
            Entry::Vacant(entry) => {
                entry.insert(timestamp_in_ms(get_time()));
                Ok(())
            },
            Entry::Occupied(_) => Err(()),
        }
    }

    pub fn time_end(&self, label: &str) -> Result<u64, ()> {
        self.console_timers.borrow_mut().remove(label).ok_or(()).map(|start| {
            timestamp_in_ms(get_time()) - start
        })
    }

    /// Get an `&IpcSender<ScriptToDevtoolsControlMsg>` to send messages
    /// to the devtools thread when available.
    pub fn devtools_chan(&self) -> Option<&IpcSender<ScriptToDevtoolsControlMsg>> {
        self.devtools_chan.as_ref()
    }

    /// Get a sender to the memory profiler thread.
    pub fn mem_profiler_chan(&self) -> &mem::ProfilerChan {
        &self.mem_profiler_chan
    }

    /// Get a sender to the time profiler thread.
    pub fn time_profiler_chan(&self) -> &time::ProfilerChan {
        &self.time_profiler_chan
    }

    /// Get a sender to the constellation thread.
    pub fn constellation_chan(&self) -> &IpcSender<ConstellationMsg> {
        &self.constellation_chan
    }

    pub fn scheduler_chan(&self) -> &IpcSender<TimerEventRequest> {
        &self.scheduler_chan
    }

    /// Get the `PipelineId` for this global scope.
    pub fn pipeline_id(&self) -> PipelineId {
        self.pipeline_id
    }

    /// Get the [base url](https://html.spec.whatwg.org/multipage/#api-base-url)
    /// for this global scope.
    pub fn api_base_url(&self) -> Url {
        if let Some(window) = self.downcast::<Window>() {
            // https://html.spec.whatwg.org/multipage/#script-settings-for-browsing-contexts:api-base-url
            return window.Document().base_url();
        }
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            // https://html.spec.whatwg.org/multipage/#script-settings-for-workers:api-base-url
            return worker.get_url().clone();
        }
        unreachable!();
    }

    /// Get the URL for this global scope.
    pub fn get_url(&self) -> Url {
        if let Some(window) = self.downcast::<Window>() {
            return window.get_url();
        }
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            return worker.get_url().clone();
        }
        unreachable!();
    }

    /// Extract a `Window`, panic if the global object is not a `Window`.
    pub fn as_window(&self) -> &Window {
        self.downcast::<Window>().expect("expected a Window scope")
    }

    /// https://html.spec.whatwg.org/multipage/#report-the-error
    pub fn report_an_error(&self, error_info: ErrorInfo, value: HandleValue) {
        // Step 1.
        if self.in_error_reporting_mode.get() {
            return;
        }

        // Step 2.
        self.in_error_reporting_mode.set(true);

        // Steps 3-12.
        // FIXME(#13195): muted errors.
        let event = ErrorEvent::new(self,
                                    atom!("error"),
                                    EventBubbles::DoesNotBubble,
                                    EventCancelable::Cancelable,
                                    error_info.message.as_str().into(),
                                    error_info.filename.as_str().into(),
                                    error_info.lineno,
                                    error_info.column,
                                    value);

        // Step 13.
        let event_status = event.upcast::<Event>().fire(self.upcast::<EventTarget>());

        // Step 15
        if event_status == EventStatus::NotCanceled {
            if let Some(dedicated) = self.downcast::<DedicatedWorkerGlobalScope>() {
                dedicated.forward_error_to_worker_object(error_info);
            }
        }

        // Step 14
        self.in_error_reporting_mode.set(false);
    }

    /// Get the `&ResourceThreads` for this global scope.
    pub fn resource_threads(&self) -> &ResourceThreads {
        &self.resource_threads
    }

    /// Get the `CoreResourceThread` for this global scope.
    pub fn core_resource_thread(&self) -> CoreResourceThread {
        self.resource_threads().sender()
    }

    /// `ScriptChan` to send messages to the event loop of this global scope.
    pub fn script_chan(&self) -> Box<ScriptChan + Send> {
        if let Some(window) = self.downcast::<Window>() {
            return MainThreadScriptChan(window.main_thread_script_chan().clone()).clone();
        }
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            return worker.script_chan();
        }
        unreachable!();
    }

    /// `ScriptChan` to send messages to the networking task source of
    /// this of this global scope.
    pub fn networking_task_source(&self) -> Box<ScriptChan + Send> {
        if let Some(window) = self.downcast::<Window>() {
            return window.networking_task_source();
        }
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            return worker.script_chan();
        }
        unreachable!();
    }

    /// Evaluate JS code on this global scope.
    pub fn evaluate_js_on_global_with_result(
            &self, code: &str, rval: MutableHandleValue) {
        self.evaluate_script_on_global_with_result(code, "", rval)
    }

    /// Evaluate a JS script on this global scope.
    #[allow(unsafe_code)]
    pub fn evaluate_script_on_global_with_result(
            &self, code: &str, filename: &str, rval: MutableHandleValue) {
        let metadata = time::TimerMetadata {
            url: if filename.is_empty() {
                self.get_url().as_str().into()
            } else {
                filename.into()
            },
            iframe: time::TimerMetadataFrameType::RootWindow,
            incremental: time::TimerMetadataReflowType::FirstReflow,
        };
        time::profile(
            time::ProfilerCategory::ScriptEvaluate,
            Some(metadata),
            self.time_profiler_chan().clone(),
            || {
                let cx = self.get_cx();
                let globalhandle = self.reflector().get_jsobject();
                let code: Vec<u16> = code.encode_utf16().collect();
                let filename = CString::new(filename).unwrap();

                let _ac = JSAutoCompartment::new(cx, globalhandle.get());
                let options = CompileOptionsWrapper::new(cx, filename.as_ptr(), 1);
                unsafe {
                    if !Evaluate2(cx, options.ptr, code.as_ptr(),
                                  code.len() as libc::size_t,
                                  rval) {
                        debug!("error evaluating JS string");
                        report_pending_exception(cx, true);
                    }
                }

                if let Some(error) = maybe_take_panic_result() {
                    panic::resume_unwind(error);
                }
            }
        )
    }

    pub fn schedule_callback(
            &self, callback: OneshotTimerCallback, duration: MsDuration)
            -> OneshotTimerHandle {
        self.timers.schedule_callback(callback, duration, self.timer_source())
    }

    pub fn unschedule_callback(&self, handle: OneshotTimerHandle) {
        self.timers.unschedule_callback(handle);
    }

    pub fn set_timeout_or_interval(
            &self,
            callback: TimerCallback,
            arguments: Vec<HandleValue>,
            timeout: i32,
            is_interval: IsInterval)
            -> i32 {
        self.timers.set_timeout_or_interval(
            self, callback, arguments, timeout, is_interval, self.timer_source())
    }

    pub fn clear_timeout_or_interval(&self, handle: i32) {
        self.timers.clear_timeout_or_interval(self, handle)
    }

    pub fn fire_timer(&self, handle: TimerEventId) {
        self.timers.fire_timer(handle, self)
    }

    pub fn resume(&self) {
        self.timers.resume()
    }

    pub fn suspend(&self) {
        self.timers.suspend()
    }

    pub fn slow_down_timers(&self) {
        self.timers.slow_down()
    }

    pub fn speed_up_timers(&self) {
        self.timers.speed_up()
    }

    fn timer_source(&self) -> TimerSource {
        if self.is::<Window>() {
            return TimerSource::FromWindow(self.pipeline_id());
        }
        if self.is::<WorkerGlobalScope>() {
            return TimerSource::FromWorker;
        }
        unreachable!();
    }

    /// Returns a wrapper for runnables to ensure they are cancelled if
    /// the global scope is being destroyed.
    pub fn get_runnable_wrapper(&self) -> RunnableWrapper {
        if let Some(window) = self.downcast::<Window>() {
            return window.get_runnable_wrapper();
        }
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            return worker.get_runnable_wrapper();
        }
        unreachable!();
    }

    /// Start the process of executing the pending promise callbacks. They will be invoked
    /// in FIFO order, synchronously, at some point in the future.
    pub fn flush_promise_jobs(&self) {
        if self.is::<Window>() {
            return ScriptThread::flush_promise_jobs(self);
        }
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            return worker.flush_promise_jobs();
        }
        unreachable!();
    }

    /// Enqueue a promise callback for subsequent execution.
    pub fn enqueue_promise_job(&self, job: EnqueuedPromiseCallback) {
        if self.is::<Window>() {
            return ScriptThread::enqueue_promise_job(job, self);
        }
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            return worker.enqueue_promise_job(job);
        }
        unreachable!();
    }

    /// Create a new sender/receiver pair that can be used to implement an on-demand
    /// event loop. Used for implementing web APIs that require blocking semantics
    /// without resorting to nested event loops.
    pub fn new_script_pair(&self) -> (Box<ScriptChan + Send>, Box<ScriptPort + Send>) {
        if let Some(window) = self.downcast::<Window>() {
            return window.new_script_pair();
        }
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            return worker.new_script_pair();
        }
        unreachable!();
    }
}

fn timestamp_in_ms(time: Timespec) -> u64 {
    (time.sec * 1000 + (time.nsec / 1000000) as i64) as u64
}