servo/src/components/script/dom/eventtarget.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 dom::bindings::callback::CallbackContainer;
use dom::bindings::codegen::BindingDeclarations::EventHandlerBinding::EventHandlerNonNull;
use dom::bindings::codegen::BindingDeclarations::EventListenerBinding::EventListener;
use dom::bindings::error::{Fallible, InvalidState};
use dom::bindings::js::JSRef;
use dom::bindings::utils::{Reflectable, Reflector};
use dom::event::Event;
use dom::eventdispatcher::dispatch_event;
use dom::node::NodeTypeId;
use dom::xmlhttprequest::XMLHttpRequestId;
use dom::virtualmethods::VirtualMethods;
use js::jsapi::{JS_CompileUCFunction, JS_GetFunctionObject, JS_CloneFunctionObject};
use js::jsapi::{JSContext, JSObject};
use servo_util::str::DOMString;
use libc::{c_char, size_t};
use std::ptr;
use url::Url;

use collections::hashmap::HashMap;

#[deriving(Eq,Encodable)]
pub enum ListenerPhase {
    Capturing,
    Bubbling,
}

#[deriving(Eq,Encodable)]
pub enum EventTargetTypeId {
    NodeTargetTypeId(NodeTypeId),
    WindowTypeId,
    XMLHttpRequestTargetTypeId(XMLHttpRequestId)
}

#[deriving(Eq, Encodable)]
pub enum EventListenerType {
    Additive(EventListener),
    Inline(EventListener),
}

impl EventListenerType {
    fn get_listener(&self) -> EventListener {
        match *self {
            Additive(listener) | Inline(listener) => listener
        }
    }
}

#[deriving(Eq,Encodable)]
pub struct EventListenerEntry {
    pub phase: ListenerPhase,
    pub listener: EventListenerType
}

#[deriving(Encodable)]
pub struct EventTarget {
    pub type_id: EventTargetTypeId,
    pub reflector_: Reflector,
    pub handlers: HashMap<DOMString, Vec<EventListenerEntry>>,
}

impl EventTarget {
    pub fn new_inherited(type_id: EventTargetTypeId) -> EventTarget {
        EventTarget {
            type_id: type_id,
            reflector_: Reflector::new(),
            handlers: HashMap::new(),
        }
    }

    pub fn get_listeners(&self, type_: &str) -> Option<Vec<EventListener>> {
        self.handlers.find_equiv(&type_).map(|listeners| {
            listeners.iter().map(|entry| entry.listener.get_listener()).collect()
        })
    }

    pub fn get_listeners_for(&self, type_: &str, desired_phase: ListenerPhase)
        -> Option<Vec<EventListener>> {
        self.handlers.find_equiv(&type_).map(|listeners| {
            let filtered = listeners.iter().filter(|entry| entry.phase == desired_phase);
            filtered.map(|entry| entry.listener.get_listener()).collect()
        })
    }
}

pub trait EventTargetHelpers {
    fn dispatch_event_with_target<'a>(&self,
                                      target: Option<JSRef<'a, EventTarget>>,
                                      event: &mut JSRef<Event>) -> Fallible<bool>;
    fn set_inline_event_listener(&mut self,
                                 ty: DOMString,
                                 listener: Option<EventListener>);
    fn get_inline_event_listener(&self, ty: DOMString) -> Option<EventListener>;
    fn set_event_handler_uncompiled(&mut self,
                                    cx: *mut JSContext,
                                    url: Url,
                                    scope: *mut JSObject,
                                    ty: &str,
                                    source: DOMString);
    fn set_event_handler_common<T: CallbackContainer>(&mut self, ty: &str,
                                                      listener: Option<T>);
    fn get_event_handler_common<T: CallbackContainer>(&self, ty: &str) -> Option<T>;
}

impl<'a> EventTargetHelpers for JSRef<'a, EventTarget> {
    fn dispatch_event_with_target<'b>(&self,
                                      target: Option<JSRef<'b, EventTarget>>,
                                      event: &mut JSRef<Event>) -> Fallible<bool> {
        if event.deref().dispatching || !event.deref().initialized {
            return Err(InvalidState);
        }
        Ok(dispatch_event(self, target, event))
    }

    fn set_inline_event_listener(&mut self,
                                 ty: DOMString,
                                 listener: Option<EventListener>) {
        let entries = self.handlers.find_or_insert_with(ty, |_| vec!());
        let idx = entries.iter().position(|&entry| {
            match entry.listener {
                Inline(_) => true,
                _ => false,
            }
        });

        match idx {
            Some(idx) => {
                match listener {
                    Some(listener) => entries.get_mut(idx).listener = Inline(listener),
                    None => {
                        entries.remove(idx);
                    }
                }
            }
            None => {
                if listener.is_some() {
                    entries.push(EventListenerEntry {
                        phase: Bubbling,
                        listener: Inline(listener.unwrap()),
                    });
                }
            }
        }
    }

    fn get_inline_event_listener(&self, ty: DOMString) -> Option<EventListener> {
        let entries = self.handlers.find(&ty);
        entries.and_then(|entries| entries.iter().find(|entry| {
            match entry.listener {
                Inline(_) => true,
                _ => false,
            }
        }).map(|entry| entry.listener.get_listener()))
    }

    fn set_event_handler_uncompiled(&mut self,
                                    cx: *mut JSContext,
                                    url: Url,
                                    scope: *mut JSObject,
                                    ty: &str,
                                    source: DOMString) {
        let url = url.to_str().to_c_str();
        let name = ty.to_c_str();
        let lineno = 0; //XXXjdm need to get a real number here

        let nargs = 1; //XXXjdm not true for onerror
        static arg_name: [c_char, ..6] =
            ['e' as c_char, 'v' as c_char, 'e' as c_char, 'n' as c_char, 't' as c_char, 0];
        static arg_names: [*c_char, ..1] = [&arg_name as *c_char];

        let source = source.to_utf16();
        let handler =
            name.with_ref(|name| {
            url.with_ref(|url| { unsafe {
                let fun = JS_CompileUCFunction(cx, ptr::mut_null(), name,
                                               nargs, &arg_names as **i8 as *mut *i8, source.as_ptr(),
                                               source.len() as size_t,
                                               url, lineno);
                assert!(fun.is_not_null());
                JS_GetFunctionObject(fun)
            }})});
        let funobj = unsafe { JS_CloneFunctionObject(cx, handler, scope) };
        assert!(funobj.is_not_null());
        self.set_event_handler_common(ty, Some(EventHandlerNonNull::new(funobj)))
    }

    fn set_event_handler_common<T: CallbackContainer>(
        &mut self, ty: &str, listener: Option<T>)
    {
        let event_listener = listener.map(|listener|
                                          EventListener::new(listener.callback()));
        self.set_inline_event_listener(ty.to_owned(), event_listener);
    }

    fn get_event_handler_common<T: CallbackContainer>(&self, ty: &str) -> Option<T> {
        let listener = self.get_inline_event_listener(ty.to_owned());
        listener.map(|listener| CallbackContainer::new(listener.parent.callback()))
    }
}

pub trait EventTargetMethods {
    fn AddEventListener(&mut self,
                        ty: DOMString,
                        listener: Option<EventListener>,
                        capture: bool);
    fn RemoveEventListener(&mut self,
                           ty: DOMString,
                           listener: Option<EventListener>,
                           capture: bool);
    fn DispatchEvent(&self, event: &mut JSRef<Event>) -> Fallible<bool>;
}

impl<'a> EventTargetMethods for JSRef<'a, EventTarget> {
    fn AddEventListener(&mut self,
                        ty: DOMString,
                        listener: Option<EventListener>,
                        capture: bool) {
        for &listener in listener.iter() {
            let entry = self.handlers.find_or_insert_with(ty.clone(), |_| vec!());
            let phase = if capture { Capturing } else { Bubbling };
            let new_entry = EventListenerEntry {
                phase: phase,
                listener: Additive(listener)
            };
            if entry.as_slice().position_elem(&new_entry).is_none() {
                entry.push(new_entry);
            }
        }
    }

    fn RemoveEventListener(&mut self,
                           ty: DOMString,
                           listener: Option<EventListener>,
                           capture: bool) {
        for &listener in listener.iter() {
            let mut entry = self.handlers.find_mut(&ty);
            for entry in entry.mut_iter() {
                let phase = if capture { Capturing } else { Bubbling };
                let old_entry = EventListenerEntry {
                    phase: phase,
                    listener: Additive(listener)
                };
                let position = entry.as_slice().position_elem(&old_entry);
                for &position in position.iter() {
                    entry.remove(position);
                }
            }
        }
    }

    fn DispatchEvent(&self, event: &mut JSRef<Event>) -> Fallible<bool> {
        self.dispatch_event_with_target(None, event)
    }
}

impl Reflectable for EventTarget {
    fn reflector<'a>(&'a self) -> &'a Reflector {
        &self.reflector_
    }

    fn mut_reflector<'a>(&'a mut self) -> &'a mut Reflector {
        &mut self.reflector_
    }
}

impl<'a> VirtualMethods for JSRef<'a, EventTarget> {
    fn super_type<'a>(&'a mut self) -> Option<&'a mut VirtualMethods:> {
        None
    }
}