servo/components/script/dom/cssstyledeclaration.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::codegen::Bindings::CSSStyleDeclarationBinding::{mod, CSSStyleDeclarationMethods};
use dom::bindings::codegen::InheritTypes::{NodeCast, ElementCast};
use dom::bindings::error::Error;
use dom::bindings::error::ErrorResult;
use dom::bindings::error::Fallible;
use dom::bindings::global::GlobalRef;
use dom::bindings::js::{JS, JSRef, OptionalRootedRootable, Temporary};
use dom::bindings::utils::{Reflector, reflect_dom_object};
use dom::document::DocumentHelpers;
use dom::element::{Element, ElementHelpers, StylePriority};
use dom::htmlelement::HTMLElement;
use dom::node::{window_from_node, document_from_node, NodeDamage, Node};
use dom::window::Window;
use servo_util::str::DOMString;
use string_cache::Atom;
use style::{is_supported_property, longhands_from_shorthand, parse_style_attribute};
use style::PropertyDeclaration;

use std::ascii::AsciiExt;

#[dom_struct]
pub struct CSSStyleDeclaration {
    reflector_: Reflector,
    owner: JS<HTMLElement>,
    readonly: bool,
}

#[deriving(PartialEq)]
pub enum CSSModificationAccess {
    ReadWrite,
    Readonly
}

macro_rules! css_properties(
    ( $([$getter:ident, $setter:ident, $cssprop:expr]),* ) => (
        $(
            fn $getter(self) -> DOMString {
                self.GetPropertyValue($cssprop.into_string())
            }
            fn $setter(self, value: DOMString) {
                self.SetPropertyValue($cssprop.into_string(), value).unwrap();
            }
        )*
    );
)

fn serialize_list(list: &Vec<PropertyDeclaration>) -> DOMString {
    let mut result = String::new();
    for declaration in list.iter() {
        result.push_str(serialize_value(declaration).as_slice());
        result.push_str(" ");
    }
    result
}

fn serialize_value(declaration: &PropertyDeclaration) -> DOMString {
    declaration.value()
}

impl CSSStyleDeclaration {
    pub fn new_inherited(owner: JSRef<HTMLElement>, modification_access: CSSModificationAccess) -> CSSStyleDeclaration {
        CSSStyleDeclaration {
            reflector_: Reflector::new(),
            owner: JS::from_rooted(owner),
            readonly: modification_access == CSSModificationAccess::Readonly,
        }
    }

    pub fn new(global: JSRef<Window>, owner: JSRef<HTMLElement>, modification_access: CSSModificationAccess) -> Temporary<CSSStyleDeclaration> {
        reflect_dom_object(box CSSStyleDeclaration::new_inherited(owner, modification_access),
                           GlobalRef::Window(global),
                           CSSStyleDeclarationBinding::Wrap)
    }
}

trait PrivateCSSStyleDeclarationHelpers {
    fn get_declaration(self, property: &Atom) -> Option<PropertyDeclaration>;
    fn get_important_declaration(self, property: &Atom) -> Option<PropertyDeclaration>;
}

impl<'a> PrivateCSSStyleDeclarationHelpers for JSRef<'a, CSSStyleDeclaration> {
    fn get_declaration(self, property: &Atom) -> Option<PropertyDeclaration> {
        let owner = self.owner.root();
        let element: JSRef<Element> = ElementCast::from_ref(owner.r());
        element.get_inline_style_declaration(property).map(|decl| decl.clone())
    }

    fn get_important_declaration(self, property: &Atom) -> Option<PropertyDeclaration> {
        let owner = self.owner.root();
        let element: JSRef<Element> = ElementCast::from_ref(owner.r());
        element.get_important_inline_style_declaration(property).map(|decl| decl.clone())
    }
}

impl<'a> CSSStyleDeclarationMethods for JSRef<'a, CSSStyleDeclaration> {
    fn Length(self) -> u32 {
        let owner = self.owner.root();
        let elem: JSRef<Element> = ElementCast::from_ref(owner.r());
        let len = match *elem.style_attribute().borrow() {
            Some(ref declarations) => declarations.normal.len() + declarations.important.len(),
            None => 0
        };
        len as u32
    }

    fn Item(self, index: u32) -> DOMString {
        let owner = self.owner.root();
        let elem: JSRef<Element> = ElementCast::from_ref(owner.r());
        let style_attribute = elem.style_attribute().borrow();
        let result = style_attribute.as_ref().and_then(|declarations| {
            if index as uint > declarations.normal.len() {
                declarations.important
                            .get(index as uint - declarations.normal.len())
                            .map(|decl| format!("{} !important", decl))
            } else {
                declarations.normal
                            .get(index as uint)
                            .map(|decl| format!("{}", decl))
            }
        });

        result.unwrap_or("".into_string())
    }

    // http://dev.w3.org/csswg/cssom/#dom-cssstyledeclaration-getpropertyvalue
    fn GetPropertyValue(self, property: DOMString) -> DOMString {
        // Step 1
        let property = Atom::from_slice(property.as_slice().to_ascii_lower().as_slice());

        // Step 2
        let longhand_properties = longhands_from_shorthand(property.as_slice());
        if let Some(longhand_properties) = longhand_properties {
            // Step 2.1
            let mut list = vec!();

            // Step 2.2
            for longhand in longhand_properties.iter() {
                // Step 2.2.1
                let declaration = self.get_declaration(&Atom::from_slice(longhand.as_slice()));

                // Step 2.2.2 & 2.2.3
                match declaration {
                    Some(declaration) => list.push(declaration),
                    None => return "".into_string(),
                }
            }

            // Step 2.3
            return serialize_list(&list);
        }

        // Step 3 & 4
        if let Some(ref declaration) = self.get_declaration(&property) {
            serialize_value(declaration)
        } else {
            "".into_string()
        }
    }

    // http://dev.w3.org/csswg/cssom/#dom-cssstyledeclaration-getpropertypriority
    fn GetPropertyPriority(self, property: DOMString) -> DOMString {
        // Step 1
        let property = Atom::from_slice(property.as_slice().to_ascii_lower().as_slice());

        // Step 2
        let longhand_properties = longhands_from_shorthand(property.as_slice());
        if let Some(longhand_properties) = longhand_properties {
            // Step 2.1 & 2.2 & 2.3
            if longhand_properties.iter()
                                  .map(|longhand| self.GetPropertyPriority(longhand.clone()))
                                  .all(|priority| priority.as_slice() == "important") {

                return "important".into_string();
            }
        // Step 3
        } else if self.get_important_declaration(&property).is_some() {
            return "important".into_string();
        }

        // Step 4
        "".into_string()
    }

    // http://dev.w3.org/csswg/cssom/#dom-cssstyledeclaration-setproperty
    fn SetProperty(self, property: DOMString, value: DOMString,
                   priority: DOMString) -> ErrorResult {
        // Step 1
        if self.readonly {
            return Err(Error::NoModificationAllowedError);
        }

        // Step 2
        let property = property.as_slice().to_ascii_lower();

        // Step 3
        if !is_supported_property(property.as_slice()) {
            return Ok(());
        }

        // Step 4
        if value.is_empty() {
            return self.RemoveProperty(property).map(|_| ());
        }

        // Step 5
        let priority = priority.as_slice().to_ascii_lower();
        if priority.as_slice() != "!important" && !priority.is_empty() {
            return Ok(());
        }

        // Step 6
        let mut synthesized_declaration = String::from_str(property.as_slice());
        synthesized_declaration.push_str(": ");
        synthesized_declaration.push_str(value.as_slice());

        let owner = self.owner.root();
        let window = window_from_node(owner.r()).root();
        let window = window.r();
        let page = window.page();
        let decl_block = parse_style_attribute(synthesized_declaration.as_slice(),
                                               &page.get_url());

        // Step 7
        if decl_block.normal.len() == 0 {
            return Ok(());
        }

        let owner = self.owner.root();
        let element: JSRef<Element> = ElementCast::from_ref(owner.r());

        // Step 8
        for decl in decl_block.normal.iter() {
            // Step 9
            let style_priority = if priority.is_empty() { StylePriority::Normal } else { StylePriority::Important };
            element.update_inline_style(decl.clone(), style_priority);
        }

        let document = document_from_node(element).root();
        let node: JSRef<Node> = NodeCast::from_ref(element);
        document.r().content_changed(node, NodeDamage::NodeStyleDamaged);
        Ok(())
    }

    // http://dev.w3.org/csswg/cssom/#dom-cssstyledeclaration-setpropertypriority
    fn SetPropertyPriority(self, property: DOMString, priority: DOMString) -> ErrorResult {
        // Step 1
        if self.readonly {
            return Err(Error::NoModificationAllowedError);
        }

        // Step 2
        let property = property.as_slice().to_ascii_lower();

        // Step 3
        if !is_supported_property(property.as_slice()) {
            return Ok(());
        }

        // Step 4
        let priority = priority.as_slice().to_ascii_lower();
        if priority.as_slice() != "important" && !priority.is_empty() {
            return Ok(());
        }

        let owner = self.owner.root();
        let window = window_from_node(owner.r()).root();
        let window = window.r();
        let page = window.page();
        let decl_block = parse_style_attribute(property.as_slice(),
                                               &page.get_url());
        let element: JSRef<Element> = ElementCast::from_ref(owner.r());

        // Step 5
        for decl in decl_block.normal.iter() {
            // Step 6
            let style_priority = if priority.is_empty() { StylePriority::Normal } else { StylePriority::Important };
            element.update_inline_style(decl.clone(), style_priority);
        }

        let document = document_from_node(element).root();
        let node: JSRef<Node> = NodeCast::from_ref(element);
        document.r().content_changed(node, NodeDamage::NodeStyleDamaged);
        Ok(())
    }

    // http://dev.w3.org/csswg/cssom/#dom-cssstyledeclaration-setpropertyvalue
    fn SetPropertyValue(self, property: DOMString, value: DOMString) -> ErrorResult {
        self.SetProperty(property, value, "".into_string())
    }

    // http://dev.w3.org/csswg/cssom/#dom-cssstyledeclaration-removeproperty
    fn RemoveProperty(self, property: DOMString) -> Fallible<DOMString> {
        // Step 1
        if self.readonly {
            return Err(Error::NoModificationAllowedError);
        }

        // Step 2
        let property = property.as_slice().to_ascii_lower();

        // Step 3
        let value = self.GetPropertyValue(property.clone());

        let longhand_properties = longhands_from_shorthand(property.as_slice());
        match longhand_properties {
            Some(longhands) => {
                // Step 4
                for longhand in longhands.iter() {
                    try!(self.RemoveProperty(longhand.clone()));
                }
            }

            None => {
                // Step 5
                let owner = self.owner.root();
                let elem: JSRef<Element> = ElementCast::from_ref(owner.r());
                elem.remove_inline_style_property(property)
            }
        }

        // Step 6
        Ok(value)
    }

    // http://dev.w3.org/csswg/cssom/#dom-cssstyledeclaration-cssfloat
    fn CssFloat(self) -> DOMString {
        self.GetPropertyValue("float".into_string())
    }

    // http://dev.w3.org/csswg/cssom/#dom-cssstyledeclaration-cssfloat
    fn SetCssFloat(self, value: DOMString) -> ErrorResult {
        self.SetPropertyValue("float".into_string(), value)
    }

    fn IndexedGetter(self, index: u32, found: &mut bool) -> DOMString {
        let rval = self.Item(index);
        *found = index < self.Length();
        rval
    }

    css_properties_accessors!(css_properties)
}