Defined new trait ParseErrorReporter and added error_reporter member to ParserContext

components/layout/Cargo.toml

@@ -38,6 +38,9 @@ path = "../script_traits"
 [dependencies.style]
 path = "../style"
 
+[dependencies.style_traits]
+path = "../style_traits"
+
 [dependencies.plugins]
 path = "../plugins"
 

components/layout/context.rs

@@ -27,6 +27,7 @@ use std::rc::Rc;
 use std::sync::mpsc::{Sender, channel};
 use std::sync::{Arc, Mutex, RwLock};
 use style::selector_matching::Stylist;
+use style_traits::ParseErrorReporter;
 use url::Url;
 use util::mem::HeapSizeOf;
 use util::opts;
@@ -127,6 +128,9 @@ pub struct SharedLayoutContext {
 
     /// Why is this reflow occurring
     pub goal: ReflowGoal,
+
+    ///The CSS error reporter for all CSS loaded in this layout thread
+    pub error_reporter: Box<ParseErrorReporter + Sync>
 }
 
 pub struct LayoutContext<'a> {

components/layout/css/matching.rs

@@ -27,6 +27,7 @@ use string_cache::{Atom, Namespace};
 use style::node::TElementAttributes;
 use style::properties::{ComputedValues, PropertyDeclaration, cascade};
 use style::selector_matching::{DeclarationBlock, Stylist};
+use style_traits::ParseErrorReporter;
 use util::arc_ptr_eq;
 use util::cache::{LRUCache, SimpleHashCache};
 use util::opts;
@@ -456,7 +457,8 @@ impl<'ln> PrivateMatchMethods for ServoLayoutNode<'ln> {
                                                         applicable_declarations,
                                                         shareable,
                                                         Some(&***parent_style),
-                                                        cached_computed_values);
+                                                        cached_computed_values,
+                                                        layout_context.error_reporter.clone());
                 cacheable = cacheable && is_cacheable;
                 this_style = the_style
             }
@@ -465,7 +467,8 @@ impl<'ln> PrivateMatchMethods for ServoLayoutNode<'ln> {
                                                         applicable_declarations,
                                                         shareable,
                                                         None,
-                                                        None);
+                                                        None,
+                                                        layout_context.error_reporter.clone());
                 cacheable = cacheable && is_cacheable;
                 this_style = the_style
             }

components/layout/layout_task.rs

@@ -49,6 +49,7 @@ use script::layout_interface::Animation;
 use script::layout_interface::{LayoutRPC, OffsetParentResponse};
 use script::layout_interface::{Msg, NewLayoutTaskInfo, Reflow, ReflowGoal, ReflowQueryType};
 use script::layout_interface::{ScriptLayoutChan, ScriptReflow};
+use script::reporter::CSSErrorReporter;
 use script_traits::{ConstellationControlMsg, LayoutControlMsg, OpaqueScriptLayoutChannel};
 use sequential;
 use serde_json;
@@ -64,6 +65,7 @@ use style::computed_values::{filter, mix_blend_mode};
 use style::media_queries::{Device, MediaType};
 use style::selector_matching::{Stylist, USER_OR_USER_AGENT_STYLESHEETS};
 use style::stylesheets::{CSSRuleIteratorExt, Stylesheet};
+use style_traits::ParseErrorReporter;
 use url::Url;
 use util::geometry::MAX_RECT;
 use util::ipc::OptionalIpcSender;
@@ -211,6 +213,10 @@ pub struct LayoutTask {
     ///
     /// All the other elements of this struct are read-only.
     rw_data: Arc<Mutex<LayoutTaskData>>,
+
+    /// The CSS error reporter for all CSS loaded in this layout thread
+    error_reporter: CSSErrorReporter,
+
 }
 
 impl LayoutTaskFactory for LayoutTask {
@@ -438,6 +444,7 @@ impl LayoutTask {
                     resolved_style_response: None,
                     offset_parent_response: OffsetParentResponse::empty(),
               })),
+              error_reporter: CSSErrorReporter,
         }
     }
 
@@ -476,6 +483,7 @@ impl LayoutTask {
             goal: goal,
             running_animations: self.running_animations.clone(),
             expired_animations: self.expired_animations.clone(),
+            error_reporter: self.error_reporter.clone(),
         }
     }
 
@@ -557,7 +565,6 @@ impl LayoutTask {
             goal: ReflowGoal::ForDisplay,
             page_clip_rect: MAX_RECT,
         };
-
         let mut layout_context = self.build_shared_layout_context(&*rw_data,
                                                                   false,
                                                                   &self.url,

components/layout/lib.rs

@@ -53,6 +53,7 @@ extern crate serde_json;
 extern crate smallvec;
 #[macro_use(atom, ns)] extern crate string_cache;
 extern crate style;
+extern crate style_traits;
 extern crate unicode_bidi;
 extern crate unicode_script;
 extern crate url;

components/script/Cargo.toml

@@ -36,6 +36,9 @@ path = "../devtools_traits"
 [dependencies.style]
 path = "../style"
 
+[dependencies.style_traits]
+path = "../style_traits"
+
 [dependencies.canvas]
 path = "../canvas"
 

components/script/dom/cssstyledeclaration.rs

@@ -18,6 +18,7 @@ use std::cell::Ref;
 use string_cache::Atom;
 use style::properties::{PropertyDeclaration, Shorthand};
 use style::properties::{is_supported_property, parse_one_declaration};
+use style_traits::ParseErrorReporter;
 use util::str::{DOMString, str_join};
 
 // http://dev.w3.org/csswg/cssom/#the-cssstyledeclaration-interface
@@ -240,7 +241,7 @@ impl CSSStyleDeclarationMethods for CSSStyleDeclaration {
 
         // Step 6
         let window = window_from_node(&*self.owner);
-        let declarations = parse_one_declaration(&property, &value, &window.get_url());
+        let declarations = parse_one_declaration(&property, &value, &window.get_url(), window.css_error_reporter());
 
         // Step 7
         let declarations = if let Ok(declarations) = declarations {

components/script/dom/element.rs

@@ -80,6 +80,7 @@ use style::properties::longhands::{self, background_image, border_spacing, font_
 use style::properties::{PropertyDeclaration, PropertyDeclarationBlock, parse_style_attribute};
 use style::values::CSSFloat;
 use style::values::specified::{self, CSSColor, CSSRGBA, LengthOrPercentage};
+use style_traits::ParseErrorReporter;
 use url::UrlParser;
 use util::mem::HeapSizeOf;
 use util::str::{DOMString, LengthOrPercentageOrAuto};
@@ -1514,7 +1515,8 @@ impl VirtualMethods for Element {
                 // Modifying the `style` attribute might change style.
                 *self.style_attribute.borrow_mut() =
                     mutation.new_value(attr).map(|value| {
-                        parse_style_attribute(&value, &doc.base_url())
+                        let win = window_from_node(self);
+                        parse_style_attribute(&value, &doc.base_url(), win.css_error_reporter())
                     });
                 if node.is_in_doc() {
                     doc.content_changed(node, NodeDamage::NodeStyleDamaged);

components/script/dom/htmllinkelement.rs

@@ -281,13 +281,17 @@ impl AsyncResponseListener for StylesheetContext {
         let environment_encoding = UTF_8 as EncodingRef;
         let protocol_encoding_label = metadata.charset.as_ref().map(|s| &**s);
         let final_url = metadata.final_url;
+
+        let elem = self.elem.root();
+        let win = window_from_node(&*elem);
+
         let mut sheet = Stylesheet::from_bytes(&data, final_url, protocol_encoding_label,
-                                               Some(environment_encoding), Origin::Author);
+                                               Some(environment_encoding), Origin::Author,
+                                               win.css_error_reporter());
         let media = self.media.take().unwrap();
         sheet.set_media(Some(media));
         let sheet = Arc::new(sheet);
 
-        let elem = self.elem.root();
         let elem = elem.r();
         let document = document_from_node(elem);
         let document = document.r();

components/script/dom/htmlstyleelement.rs

@@ -58,7 +58,7 @@ impl HTMLStyleElement {
         };
 
         let data = node.GetTextContent().expect("Element.textContent must be a string");
-        let mut sheet = Stylesheet::from_str(&data, url, Origin::Author);
+        let mut sheet = Stylesheet::from_str(&data, url, Origin::Author, win.css_error_reporter());
         let mut css_parser = CssParser::new(&mq_str);
         let media = parse_media_query_list(&mut css_parser);
         sheet.set_media(Some(media));

components/script/dom/window.rs

@@ -52,6 +52,7 @@ use net_traits::storage_task::{StorageTask, StorageType};
 use num::traits::ToPrimitive;
 use page::Page;
 use profile_traits::mem;
+use reporter::CSSErrorReporter;
 use rustc_serialize::base64::{FromBase64, STANDARD, ToBase64};
 use script_task::{ScriptChan, ScriptPort, MainThreadScriptMsg, RunnableWrapper};
 use script_task::{SendableMainThreadScriptChan, MainThreadScriptChan};
@@ -70,6 +71,7 @@ use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::mpsc::TryRecvError::{Disconnected, Empty};
 use std::sync::mpsc::{Sender, channel};
 use string_cache::Atom;
+use style_traits::ParseErrorReporter;
 use time;
 use timers::{ActiveTimers, IsInterval, ScheduledCallback, TimerCallback, TimerHandle};
 use url::Url;
@@ -216,6 +218,8 @@ pub struct Window {
     /// A flag to prevent async events from attempting to interact with this window.
     #[ignore_heap_size_of = "defined in std"]
     ignore_further_async_events: Arc<AtomicBool>,
+
+    error_reporter: CSSErrorReporter,
 }
 
 impl Window {
@@ -289,6 +293,10 @@ impl Window {
     pub fn storage_task(&self) -> StorageTask {
         self.storage_task.clone()
     }
+
+    pub fn css_error_reporter(&self) -> Box<ParseErrorReporter + Send> {
+        return self.error_reporter.clone();
+    }
 }
 
 // https://html.spec.whatwg.org/multipage/#atob
@@ -1243,7 +1251,7 @@ impl Window {
             lchan.send(Msg::GetRPC(rpc_send)).unwrap();
             rpc_recv.recv().unwrap()
         };
-
+        let error_reporter = CSSErrorReporter;
         let win = box Window {
             eventtarget: EventTarget::new_inherited(),
             script_chan: script_chan,
@@ -1288,8 +1296,8 @@ impl Window {
             devtools_markers: DOMRefCell::new(HashSet::new()),
             devtools_wants_updates: Cell::new(false),
             webdriver_script_chan: DOMRefCell::new(None),
-
             ignore_further_async_events: Arc::new(AtomicBool::new(false)),
+            error_reporter: error_reporter
         };
 
         WindowBinding::Wrap(runtime.cx(), win)

components/script/lib.rs

@@ -42,6 +42,7 @@ extern crate log;
 extern crate profile_traits;
 #[macro_use]
 extern crate style;
+extern crate style_traits;
 #[macro_use]
 extern crate util;
 extern crate angle;
@@ -90,6 +91,7 @@ mod mem;
 mod network_listener;
 pub mod page;
 pub mod parse;
+pub mod reporter;
 #[allow(unsafe_code)]
 pub mod script_task;
 pub mod textinput;

components/script/reporter.rs

@@ -0,0 +1,25 @@
+/* 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 cssparser::{Parser, SourcePosition};
+use log;
+use style_traits::ParseErrorReporter;
+
+#[derive(JSTraceable, HeapSizeOf)]
+pub struct CSSErrorReporter;
+
+impl ParseErrorReporter for CSSErrorReporter {
+     fn report_error(&self, input: &mut Parser, position: SourcePosition, message: &str) {
+         if log_enabled!(log::LogLevel::Info) {
+             let location = input.source_location(position);
+             // TODO eventually this will got into a "web console" or something.
+             info!("{}:{} {}", location.line, location.column, message)
+         }
+     }
+
+     fn clone(&self) -> Box<ParseErrorReporter + Send + Sync> {
+         let error_reporter = box CSSErrorReporter;
+         return error_reporter;
+     }
+}

components/servo/Cargo.lock

@@ -1028,6 +1028,7 @@ dependencies = [
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
+ "style_traits 0.0.1",
  "unicode-bidi 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-script 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.37 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1550,6 +1551,7 @@ dependencies = [
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
+ "style_traits 0.0.1",
  "tendril 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicase 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",

components/style/parser.rs

@@ -6,6 +6,7 @@
 use cssparser::{Parser, SourcePosition};
 use log;
 use selectors::parser::ParserContext as SelectorParserContext;
+use style_traits::ParseErrorReporter;
 use stylesheets::Origin;
 use url::{Url, UrlParser};
 
@@ -13,16 +14,19 @@ pub struct ParserContext<'a> {
     pub stylesheet_origin: Origin,
     pub base_url: &'a Url,
     pub selector_context: SelectorParserContext,
+    pub error_reporter: Box<ParseErrorReporter + Send>
 }
 
 impl<'a> ParserContext<'a> {
-    pub fn new(stylesheet_origin: Origin, base_url: &'a Url) -> ParserContext<'a> {
+    pub fn new(stylesheet_origin: Origin, base_url: &'a Url, error_reporter: Box<ParseErrorReporter + Send>)
+               -> ParserContext<'a> {
         let mut selector_context = SelectorParserContext::new();
         selector_context.in_user_agent_stylesheet = stylesheet_origin == Origin::UserAgent;
         ParserContext {
             stylesheet_origin: stylesheet_origin,
             base_url: base_url,
             selector_context: selector_context,
+            error_reporter: error_reporter,
         }
     }
 }

components/style/properties.mako.rs

@@ -22,7 +22,7 @@ use euclid::SideOffsets2D;
 use euclid::size::Size2D;
 use fnv::FnvHasher;
 use string_cache::Atom;
-
+use style_traits::ParseErrorReporter;
 use computed_values;
 use parser::{ParserContext, log_css_error};
 use selectors::matching::DeclarationBlock;
@@ -135,6 +135,7 @@ pub mod longhands {
             use properties::{ComputedValues, PropertyDeclaration};
             use std::collections::HashMap;
             use std::sync::Arc;
+            use style_traits::ParseErrorReporter;
             use values::computed::ToComputedValue;
             use values::{computed, specified};
             use string_cache::Atom;
@@ -145,7 +146,8 @@ pub mod longhands {
                                     inherited_style: &ComputedValues,
                                     context: &computed::Context,
                                     seen: &mut PropertyBitField,
-                                    cacheable: &mut bool) {
+                                    cacheable: &mut bool,
+                                    error_reporter: Box<ParseErrorReporter + Send>) {
                 let declared_value = match *declaration {
                     PropertyDeclaration::${property.camel_case}(ref declared_value) => {
                         declared_value
@@ -174,7 +176,7 @@ pub mod longhands {
                                                .${property.ident}
                                                .clone()
                             }
-                        }
+                        }, error_reporter.clone()
                     );
                     Arc::make_mut(&mut style.${THIS_STYLE_STRUCT.ident}).${property.ident} =
                         computed_value;
@@ -186,7 +188,8 @@ pub mod longhands {
                                                 inherited_style,
                                                 context,
                                                 seen,
-                                                cacheable);
+                                                cacheable,
+                                                error_reporter);
                     % endif
                 % else:
                     // Do not allow stylesheets to set derived properties.
@@ -533,7 +536,8 @@ pub mod longhands {
                                    _inherited_style: &ComputedValues,
                                    context: &computed::Context,
                                    _seen: &mut PropertyBitField,
-                                   _cacheable: &mut bool) {
+                                   _cacheable: &mut bool,
+                                   _error_reporter: Box<ParseErrorReporter + Send>) {
             Arc::make_mut(&mut style.box_)._servo_display_for_hypothetical_box =
                 longhands::_servo_display_for_hypothetical_box::derive_from_display(
                     *computed_value,
@@ -2234,7 +2238,8 @@ pub mod longhands {
                                    _inherited_style: &ComputedValues,
                                    context: &computed::Context,
                                    _seen: &mut PropertyBitField,
-                                   _cacheable: &mut bool) {
+                                   _cacheable: &mut bool,
+                                   _error_reporter: Box<ParseErrorReporter + Send>) {
             Arc::make_mut(&mut style.inheritedtext)._servo_text_decorations_in_effect =
                 longhands::_servo_text_decorations_in_effect::derive_from_text_decoration(
                     *computed_value,
@@ -5613,7 +5618,7 @@ mod property_bit_field {
         fn substitute_variables_${property.ident}<F, R>(
             value: &DeclaredValue<longhands::${property.ident}::SpecifiedValue>,
             custom_properties: &Option<Arc<::custom_properties::ComputedValuesMap>>,
-            f: F)
+            f: F, error_reporter: Box<ParseErrorReporter + Send>)
             -> R
             where F: FnOnce(&DeclaredValue<longhands::${property.ident}::SpecifiedValue>) -> R
         {
@@ -5625,7 +5630,7 @@ mod property_bit_field {
                     .and_then(|css| {
                         // As of this writing, only the base URL is used for property values:
                         let context = ParserContext::new(
-                            ::stylesheets::Origin::Author, base_url);
+                            ::stylesheets::Origin::Author, base_url, error_reporter);
                         Parser::new(&css).parse_entirely(|input| {
                             match from_shorthand {
                                 None => {
@@ -5668,15 +5673,15 @@ pub struct PropertyDeclarationBlock {
     pub normal: Arc<Vec<PropertyDeclaration>>,
 }
 
-
+pub fn parse_style_attribute(input: &str, base_url: &Url, error_reporter: Box<ParseErrorReporter + Send>)
-pub fn parse_style_attribute(input: &str, base_url: &Url) -> PropertyDeclarationBlock {
+                             -> PropertyDeclarationBlock {
-    let context = ParserContext::new(Origin::Author, base_url);
+    let context = ParserContext::new(Origin::Author, base_url, error_reporter);
     parse_property_declaration_list(&context, &mut Parser::new(input))
 }
 
-pub fn parse_one_declaration(name: &str, input: &str, base_url: &Url)
+pub fn parse_one_declaration(name: &str, input: &str, base_url: &Url, error_reporter: Box<ParseErrorReporter + Send>)
                              -> Result<Vec<PropertyDeclaration>, ()> {
-    let context = ParserContext::new(Origin::Author, base_url);
+    let context = ParserContext::new(Origin::Author, base_url, error_reporter);
     let mut results = vec![];
     match PropertyDeclaration::parse(name, &context, &mut Parser::new(input), &mut results) {
         PropertyDeclarationParseResult::ValidOrIgnoredDeclaration => Ok(results),
@@ -6389,7 +6394,8 @@ fn cascade_with_cached_declarations(
         parent_style: &ComputedValues,
         cached_style: &ComputedValues,
         custom_properties: Option<Arc<::custom_properties::ComputedValuesMap>>,
-        context: &computed::Context)
+        context: &computed::Context,
+        error_reporter: Box<ParseErrorReporter + Send>)
         -> ComputedValues {
     % for style_struct in STYLE_STRUCTS:
         % if style_struct.inherited:
@@ -6433,7 +6439,7 @@ fn cascade_with_cached_declarations(
                                                             .clone()
                                             }
                                             DeclaredValue::WithVariables { .. } => unreachable!()
-                                        }
+                                        }, error_reporter.clone()
                                     );
                                     Arc::make_mut(&mut style_${style_struct.ident})
                                         .${property.ident} = computed_value;
@@ -6488,7 +6494,8 @@ type CascadePropertyFn = extern "Rust" fn(declaration: &PropertyDeclaration,
                                           inherited_style: &ComputedValues,
                                           context: &computed::Context,
                                           seen: &mut PropertyBitField,
-                                          cacheable: &mut bool);
+                                          cacheable: &mut bool,
+                                          error_reporter: Box<ParseErrorReporter + Send>);
 
 // This is a thread-local rather than a lazy static to avoid atomic operations when cascading
 // properties.
@@ -6533,7 +6540,8 @@ pub fn cascade(viewport_size: Size2D<Au>,
                applicable_declarations: &[DeclarationBlock<Vec<PropertyDeclaration>>],
                shareable: bool,
                parent_style: Option< &ComputedValues >,
-               cached_style: Option< &ComputedValues >)
+               cached_style: Option< &ComputedValues >,
+               error_reporter: Box<ParseErrorReporter + Send>)
                -> (ComputedValues, bool) {
     let initial_values = &*INITIAL_VALUES;
     let (is_root_element, inherited_style) = match parent_style {
@@ -6588,7 +6596,7 @@ pub fn cascade(viewport_size: Size2D<Au>,
 
     // This assumes that the computed and specified values have the same Rust type.
     macro_rules! get_specified(
-        ($style_struct_getter: ident, $property: ident, $declared_value: expr) => {
+        ($style_struct_getter: ident, $property: ident, $declared_value: expr, $error_reporter: expr) => {
             concat_idents!(substitute_variables_, $property)(
                 $declared_value, &custom_properties, |value| match *value {
                     DeclaredValue::Value(specified_value) => specified_value,
@@ -6597,7 +6605,7 @@ pub fn cascade(viewport_size: Size2D<Au>,
                         inherited_style.$style_struct_getter().$property.clone()
                     }
                     DeclaredValue::WithVariables { .. } => unreachable!()
-                }
+                }, $error_reporter.clone()
             )
         };
     );
@@ -6636,7 +6644,7 @@ pub fn cascade(viewport_size: Size2D<Au>,
                             DeclaredValue::Initial => longhands::font_size::get_initial_value(),
                             DeclaredValue::Inherit => context.inherited_font_size,
                             DeclaredValue::WithVariables { .. } => unreachable!(),
-                        }
+                        }, error_reporter.clone()
                     );
                 }
                 PropertyDeclaration::Color(ref value) => {
@@ -6648,35 +6656,35 @@ pub fn cascade(viewport_size: Size2D<Au>,
                             DeclaredValue::Initial => longhands::color::get_initial_value(),
                             DeclaredValue::Inherit => inherited_style.get_color().color.clone(),
                             DeclaredValue::WithVariables { .. } => unreachable!(),
-                        }
+                        }, error_reporter.clone()
                     );
                 }
                 PropertyDeclaration::Display(ref value) => {
-                    context.display = get_specified!(get_box, display, value);
+                    context.display = get_specified!(get_box, display, value, error_reporter.clone());
                 }
                 PropertyDeclaration::Position(ref value) => {
-                    context.positioned = match get_specified!(get_box, position, value) {
+                    context.positioned = match get_specified!(get_box, position, value, error_reporter.clone()) {
                         longhands::position::SpecifiedValue::absolute |
                         longhands::position::SpecifiedValue::fixed => true,
                         _ => false,
                     }
                 }
                 PropertyDeclaration::OverflowX(ref value) => {
-                    context.overflow_x = get_specified!(get_box, overflow_x, value);
+                    context.overflow_x = get_specified!(get_box, overflow_x, value, error_reporter.clone());
                 }
                 PropertyDeclaration::OverflowY(ref value) => {
-                    context.overflow_y = get_specified!(get_box, overflow_y, value);
+                    context.overflow_y = get_specified!(get_box, overflow_y, value, error_reporter.clone());
                 }
                 PropertyDeclaration::Float(ref value) => {
-                    context.floated = get_specified!(get_box, float, value)
+                    context.floated = get_specified!(get_box, float, value, error_reporter.clone())
                                       != longhands::float::SpecifiedValue::none;
                 }
                 PropertyDeclaration::TextDecoration(ref value) => {
-                    context.text_decoration = get_specified!(get_text, text_decoration, value);
+                    context.text_decoration = get_specified!(get_text, text_decoration, value, error_reporter.clone());
                 }
                 PropertyDeclaration::OutlineStyle(ref value) => {
                     context.outline_style_present =
-                        match get_specified!(get_outline, outline_style, value) {
+                        match get_specified!(get_outline, outline_style, value, error_reporter.clone()) {
                             BorderStyle::none => false,
                             _ => true,
                         };
@@ -6684,7 +6692,7 @@ pub fn cascade(viewport_size: Size2D<Au>,
                 % for side in ["top", "right", "bottom", "left"]:
                     PropertyDeclaration::Border${side.capitalize()}Style(ref value) => {
                         context.border_${side}_present =
-                            match get_specified!(get_border, border_${side}_style, value) {
+                            match get_specified!(get_border, border_${side}_style, value, error_reporter.clone()) {
                                 BorderStyle::none | BorderStyle::hidden => false,
                                 _ => true,
                             };
@@ -6702,7 +6710,8 @@ pub fn cascade(viewport_size: Size2D<Au>,
                                                      parent_style,
                                                      cached_style,
                                                      custom_properties,
-                                                     &context), false)
+                                                     &context,
+                                                     error_reporter), false)
         }
         (_, _) => {}
     }
@@ -6746,7 +6755,8 @@ pub fn cascade(viewport_size: Size2D<Au>,
                                                           inherited_style,
                                                           &context,
                                                           &mut seen,
-                                                          &mut cacheable);
+                                                          &mut cacheable,
+                                                          error_reporter.clone());
             }
         }
     });

components/style/selector_matching.rs

@@ -2,6 +2,8 @@
  * 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 cssparser::{Parser, SourcePosition};
+use log;
 use media_queries::{Device, MediaType};
 use node::TElementAttributes;
 use properties::{PropertyDeclaration, PropertyDeclarationBlock};
@@ -14,6 +16,7 @@ use selectors::parser::PseudoElement;
 use selectors::states::*;
 use smallvec::VecLike;
 use std::process;
+use style_traits::ParseErrorReporter;
 use style_traits::viewport::ViewportConstraints;
 use stylesheets::{CSSRuleIteratorExt, Origin, Stylesheet};
 use url::Url;
@@ -24,6 +27,20 @@ use viewport::{MaybeNew, ViewportRuleCascade};
 
 pub type DeclarationBlock = GenericDeclarationBlock<Vec<PropertyDeclaration>>;
 
+struct StdoutErrorReporter;
+
+impl ParseErrorReporter for StdoutErrorReporter {
+    fn report_error(&self, input: &mut Parser, position: SourcePosition, message: &str) {
+         if log_enabled!(log::LogLevel::Info) {
+             let location = input.source_location(position);
+             info!("{}:{} {}", location.line, location.column, message)
+         }
+    }
+
+    fn clone(&self) -> Box<ParseErrorReporter + Send + Sync> {
+        box StdoutErrorReporter
+    }
+}
 
 lazy_static! {
     pub static ref USER_OR_USER_AGENT_STYLESHEETS: Vec<Stylesheet> = {
@@ -38,7 +55,8 @@ lazy_static! {
                         Url::parse(&format!("chrome:///{:?}", filename)).unwrap(),
                         None,
                         None,
-                        Origin::UserAgent);
+                        Origin::UserAgent,
+                        box StdoutErrorReporter);
                     stylesheets.push(ua_stylesheet);
                 }
                 Err(..) => {
@@ -49,7 +67,7 @@ lazy_static! {
         }
         for &(ref contents, ref url) in &opts::get().user_stylesheets {
             stylesheets.push(Stylesheet::from_bytes(
-                &contents, url.clone(), None, None, Origin::User));
+                &contents, url.clone(), None, None, Origin::User, box StdoutErrorReporter));
         }
         stylesheets
     };
@@ -64,7 +82,8 @@ lazy_static! {
                     url!("chrome:///quirks-mode.css"),
                     None,
                     None,
-                    Origin::UserAgent)
+                    Origin::UserAgent,
+                    box StdoutErrorReporter)
             },
             Err(..) => {
                 error!("Stylist failed to load 'quirks-mode.css'!");

components/style/stylesheets.rs

@@ -16,10 +16,12 @@ use std::cell::Cell;
 use std::iter::Iterator;
 use std::slice;
 use string_cache::{Atom, Namespace};
+use style_traits::ParseErrorReporter;
 use url::Url;
 use util::mem::HeapSizeOf;
 use viewport::ViewportRule;
 
+
 /// Each style rule has an origin, which determines where it enters the cascade.
 ///
 /// http://dev.w3.org/csswg/css-cascade/#cascading-origins
@@ -80,31 +82,33 @@ pub struct StyleRule {
 impl Stylesheet {
     pub fn from_bytes_iter<I: Iterator<Item=Vec<u8>>>(
             input: I, base_url: Url, protocol_encoding_label: Option<&str>,
-            environment_encoding: Option<EncodingRef>, origin: Origin) -> Stylesheet {
+            environment_encoding: Option<EncodingRef>, origin: Origin,
+            error_reporter: Box<ParseErrorReporter + Send>) -> Stylesheet {
         let mut bytes = vec![];
         // TODO: incremental decoding and tokenization/parsing
         for chunk in input {
             bytes.push_all(&chunk)
         }
         Stylesheet::from_bytes(&bytes, base_url, protocol_encoding_label,
-                               environment_encoding, origin)
+                               environment_encoding, origin, error_reporter)
     }
 
     pub fn from_bytes(bytes: &[u8],
                       base_url: Url,
                       protocol_encoding_label: Option<&str>,
                       environment_encoding: Option<EncodingRef>,
-                      origin: Origin)
+                      origin: Origin, error_reporter: Box<ParseErrorReporter + Send>)
                       -> Stylesheet {
         // TODO: bytes.as_slice could be bytes.container_as_bytes()
         let (string, _) = decode_stylesheet_bytes(
             bytes, protocol_encoding_label, environment_encoding);
-        Stylesheet::from_str(&string, base_url, origin)
+        Stylesheet::from_str(&string, base_url, origin, error_reporter)
     }
 
-    pub fn from_str(css: &str, base_url: Url, origin: Origin) -> Stylesheet {
+    pub fn from_str(css: &str, base_url: Url, origin: Origin,
+                    error_reporter: Box<ParseErrorReporter + Send>) -> Stylesheet {
         let rule_parser = TopLevelRuleParser {
-            context: ParserContext::new(origin, &base_url),
+            context: ParserContext::new(origin, &base_url, error_reporter),
             state: Cell::new(State::Start),
         };
         let mut input = Parser::new(css);

components/style_traits/lib.rs

@@ -24,3 +24,9 @@ extern crate util;
 #[macro_use]
 pub mod values;
 pub mod viewport;
+
+use cssparser::{Parser, SourcePosition};
+pub trait ParseErrorReporter {
+    fn report_error(&self, input: &mut Parser, position: SourcePosition, message: &str);
+    fn clone(&self) -> Box<ParseErrorReporter + Send + Sync>;
+}

ports/cef/Cargo.lock

@@ -977,6 +977,7 @@ dependencies = [
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
+ "style_traits 0.0.1",
  "unicode-bidi 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-script 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.37 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1464,6 +1465,7 @@ dependencies = [
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
+ "style_traits 0.0.1",
  "tendril 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicase 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",

ports/gonk/Cargo.lock

@@ -957,6 +957,7 @@ dependencies = [
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
+ "style_traits 0.0.1",
  "unicode-bidi 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-script 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.37 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1444,6 +1445,7 @@ dependencies = [
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
+ "style_traits 0.0.1",
  "tendril 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicase 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",

tests/unit/style/media_queries.rs

@@ -3,16 +3,28 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use app_units::Au;
+use cssparser::{Parser, SourcePosition};
 use euclid::size::Size2D;
 use std::borrow::ToOwned;
 use style::media_queries::*;
 use style::stylesheets::{Origin, Stylesheet, CSSRuleIteratorExt};
 use style::values::specified;
+use style_traits::ParseErrorReporter;
 
+pub struct CSSErrorReporterTest;
+
+impl ParseErrorReporter for CSSErrorReporterTest {
+     fn report_error(&self, _input: &mut Parser, _position: SourcePosition, _message: &str) {
+     }
+     fn clone(&self) -> Box<ParseErrorReporter + Send + Sync> {
+         let error_reporter = Box::new(CSSErrorReporterTest);
+         return error_reporter;
+     }
+}
 
 fn test_media_rule<F>(css: &str, callback: F) where F: Fn(&MediaQueryList, &str) {
     let url = url!("http://localhost");
-    let stylesheet = Stylesheet::from_str(css, url, Origin::Author);
+    let stylesheet = Stylesheet::from_str(css, url, Origin::Author, Box::new(CSSErrorReporterTest));
     let mut rule_count = 0;
     for rule in stylesheet.rules().media() {
         rule_count += 1;
@@ -23,7 +35,7 @@ fn test_media_rule<F>(css: &str, callback: F) where F: Fn(&MediaQueryList, &str)
 
 fn media_query_test(device: &Device, css: &str, expected_rule_count: usize) {
     let url = url!("http://localhost");
-    let ss = Stylesheet::from_str(css, url, Origin::Author);
+    let ss = Stylesheet::from_str(css, url, Origin::Author, Box::new(CSSErrorReporterTest));
     let rule_count = ss.effective_rules(device).style().count();
     assert!(rule_count == expected_rule_count, css.to_owned());
 }

tests/unit/style/stylesheets.rs

@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use cssparser;
+use media_queries::CSSErrorReporterTest;
 use selectors::parser::*;
 use std::borrow::ToOwned;
 use std::sync::Arc;
@@ -10,7 +11,6 @@ use string_cache::Atom;
 use style::properties::{PropertyDeclaration, PropertyDeclarationBlock, DeclaredValue, longhands};
 use style::stylesheets::{CSSRule, StyleRule, Origin, Stylesheet};
 
-
 #[test]
 fn test_parse_stylesheet() {
     let css = r"
@@ -21,7 +21,7 @@ fn test_parse_stylesheet() {
         #d1 > .ok { background: blue; }
     ";
     let url = url!("about::test");
-    let stylesheet = Stylesheet::from_str(css, url, Origin::UserAgent);
+    let stylesheet = Stylesheet::from_str(css, url, Origin::UserAgent, Box::new(CSSErrorReporterTest));
     assert_eq!(stylesheet, Stylesheet {
         origin: Origin::UserAgent,
         media: None,

tests/unit/style/viewport.rs

@@ -5,6 +5,7 @@
 use cssparser::Parser;
 use euclid::scale_factor::ScaleFactor;
 use euclid::size::Size2D;
+use media_queries::CSSErrorReporterTest;
 use style::media_queries::{Device, MediaType};
 use style::parser::ParserContext;
 use style::stylesheets::{Origin, Stylesheet, CSSRuleIteratorExt};
@@ -12,11 +13,12 @@ use style::values::specified::Length::{self, ViewportPercentage};
 use style::values::specified::LengthOrPercentageOrAuto::{self, Auto};
 use style::values::specified::ViewportPercentageLength::Vw;
 use style::viewport::*;
+use style_traits::ParseErrorReporter;
 use style_traits::viewport::*;
 
 macro_rules! stylesheet {
-    ($css:expr, $origin:ident) => {
+    ($css:expr, $origin:ident, $error_reporter:expr) => {
-        Stylesheet::from_str($css, url!("http://localhost"), Origin::$origin);
+        Stylesheet::from_str($css, url!("http://localhost"), Origin::$origin, $error_reporter);
     }
 }
 
@@ -27,8 +29,7 @@ fn test_viewport_rule<F>(css: &str,
 {
     ::util::prefs::set_pref("layout.viewport.enabled",
                             ::util::prefs::PrefValue::Boolean(true));
-
+    let stylesheet = stylesheet!(css, Author, Box::new(CSSErrorReporterTest));
-    let stylesheet = stylesheet!(css, Author);
     let mut rule_count = 0;
     for rule in stylesheet.effective_rules(&device).viewport() {
         rule_count += 1;
@@ -244,11 +245,11 @@ fn multiple_stylesheets_cascading() {
     ::util::prefs::set_pref("layout.viewport.enabled",
                             ::util::prefs::PrefValue::Boolean(true));
     let device = Device::new(MediaType::Screen, Size2D::typed(800., 600.));
-
+    let error_reporter = CSSErrorReporterTest;
     let stylesheets = vec![
-        stylesheet!("@viewport { min-width: 100px; min-height: 100px; zoom: 1; }", UserAgent),
+        stylesheet!("@viewport { min-width: 100px; min-height: 100px; zoom: 1; }", UserAgent, error_reporter.clone()),
-        stylesheet!("@viewport { min-width: 200px; min-height: 200px; }", User),
+        stylesheet!("@viewport { min-width: 200px; min-height: 200px; }", User, error_reporter.clone()),
-        stylesheet!("@viewport { min-width: 300px; }", Author)];
+        stylesheet!("@viewport { min-width: 300px; }", Author, error_reporter.clone())];
 
     let declarations = stylesheets.iter()
         .flat_map(|s| s.effective_rules(&device).viewport())
@@ -260,11 +261,11 @@ fn multiple_stylesheets_cascading() {
     assert_decl_eq!(&declarations[2], Author, MinWidth: viewport_length!(300., px));
 
     let stylesheets = vec![
-        stylesheet!("@viewport { min-width: 100px !important; }", UserAgent),
+        stylesheet!("@viewport { min-width: 100px !important; }", UserAgent, error_reporter.clone()),
-        stylesheet!("@viewport { min-width: 200px !important; min-height: 200px !important; }", User),
+        stylesheet!("@viewport { min-width: 200px !important; min-height: 200px !important; }",
-        stylesheet!(
+        User, error_reporter.clone()),
-            "@viewport { min-width: 300px !important; min-height: 300px !important; zoom: 3 !important; }", Author)];
+        stylesheet!("@viewport { min-width: 300px !important; min-height: 300px !important; zoom: 3 !important; }",
-
+        Author, error_reporter.clone())];
     let declarations = stylesheets.iter()
         .flat_map(|s| s.effective_rules(&device).viewport())
         .cascade()
@@ -278,7 +279,7 @@ fn multiple_stylesheets_cascading() {
 #[test]
 fn constrain_viewport() {
     let url = url!("http://localhost");
-    let context = ParserContext::new(Origin::Author, &url);
+    let context = ParserContext::new(Origin::Author, &url, Box::new(CSSErrorReporterTest));
 
     macro_rules! from_css {
         ($css:expr) => {