Move CSS Writing Modes properties behind a new command-line flag.

src/components/main/servo.rs

@@ -94,6 +94,7 @@ pub extern "C" fn android_start(argc: int, argv: **u8) -> int {
 
 #[cfg(not(test))]
 pub fn run(opts: opts::Opts) {
+    ::servo_util::opts::set_experimental_enabled(opts.enable_experimental);
     let mut pool_config = green::PoolConfig::new();
     pool_config.event_loop_factory = rustuv::event_loop;
     let mut pool = green::SchedPool::new(pool_config);

src/components/style/properties/mod.rs.mako

@@ -35,14 +35,15 @@ def to_rust_ident(name):
     return name
 
 class Longhand(object):
-    def __init__(self, name, derived_from=None):
+    def __init__(self, name, derived_from=None, experimental=False):
         self.name = name
         self.ident = to_rust_ident(name)
         self.camel_case, _ = re.subn(
             "_([a-z])",
             lambda m: m.group(1).upper(),
             self.ident.strip("_").capitalize())
         self.style_struct = THIS_STYLE_STRUCT
+        self.experimental = experimental
         if derived_from is None:
             self.derived_from = None
         else:
@@ -94,12 +95,12 @@ pub mod longhands {
         value
     }
 
-    <%def name="raw_longhand(name, no_super=False, derived_from=None)">
+    <%def name="raw_longhand(name, no_super=False, derived_from=None, experimental=False)">
     <%
         if derived_from is not None:
             derived_from = derived_from.split()
 
-        property = Longhand(name, derived_from=derived_from)
+        property = Longhand(name, derived_from=derived_from, experimental=experimental)
         THIS_STYLE_STRUCT.longhands.append(property)
         LONGHANDS.append(property)
         LONGHANDS_BY_NAME[name] = property
@@ -128,8 +129,9 @@ pub mod longhands {
         }
     </%def>
 
-    <%def name="longhand(name, no_super=False, derived_from=None)">
-        <%self:raw_longhand name="${name}" derived_from="${derived_from}">
+    <%def name="longhand(name, no_super=False, derived_from=None, experimental=False)">
+        <%self:raw_longhand name="${name}" derived_from="${derived_from}"
+                            experimental="${experimental}">
             ${caller.body()}
             % if derived_from is None:
                 pub fn parse_specified(_input: &[ComponentValue], _base_url: &Url)
@@ -140,17 +142,18 @@ pub mod longhands {
         </%self:raw_longhand>
     </%def>
 
-    <%def name="single_component_value(name, derived_from=None)">
-        <%self:longhand name="${name}" derived_from="${derived_from}">
+    <%def name="single_component_value(name, derived_from=None, experimental=False)">
+        <%self:longhand name="${name}" derived_from="${derived_from}"
+                        experimental="${experimental}">
             ${caller.body()}
             pub fn parse(input: &[ComponentValue], base_url: &Url) -> Option<SpecifiedValue> {
                 one_component_value(input).and_then(|c| from_component_value(c, base_url))
             }
         </%self:longhand>
     </%def>
 
-    <%def name="single_keyword_computed(name, values)">
-        <%self:single_component_value name="${name}">
+    <%def name="single_keyword_computed(name, values, experimental=False)">
+        <%self:single_component_value name="${name}" experimental="${experimental}">
             ${caller.body()}
             pub mod computed_value {
                 #[allow(non_camel_case_types)]
@@ -179,9 +182,10 @@ pub mod longhands {
         </%self:single_component_value>
     </%def>
 
-    <%def name="single_keyword(name, values)">
+    <%def name="single_keyword(name, values, experimental=False)">
         <%self:single_keyword_computed name="${name}"
-                                       values="${values}">
+                                       values="${values}"
+                                       experimental="${experimental}">
             // The computed value is the same as the specified value.
             pub use to_computed_value = super::computed_as_specified;
         </%self:single_keyword_computed>
@@ -323,7 +327,7 @@ pub mod longhands {
 
     ${new_style_struct("InheritedBox", is_inherited=True)}
 
-    ${single_keyword("direction", "ltr rtl")}
+    ${single_keyword("direction", "ltr rtl", experimental=True)}
 
     // CSS 2.1, Section 10 - Visual formatting model details
 
@@ -1041,11 +1045,11 @@ pub mod longhands {
     // http://dev.w3.org/csswg/css-writing-modes/
     ${switch_to_style_struct("InheritedBox")}
 
-    ${single_keyword("writing-mode", "horizontal-tb vertical-rl vertical-lr")}
+    ${single_keyword("writing-mode", "horizontal-tb vertical-rl vertical-lr", experimental=True)}
 
     // FIXME(SimonSapin): Add 'mixed' and 'upright' (needs vertical text support)
     // FIXME(SimonSapin): initial (first) value should be 'mixed', when that's implemented
-    ${single_keyword("text-orientation", "sideways sideways-left sideways-right")}
+    ${single_keyword("text-orientation", "sideways sideways-left sideways-right", experimental=True)}
 }
 
 
@@ -1436,6 +1440,10 @@ pub fn parse_property_declaration_list<I: Iterator<Node>>(input: I, base_url: &U
                 match PropertyDeclaration::parse(n.as_slice(), v.as_slice(), list, base_url, seen) {
                     UnknownProperty => log_css_error(l, format!(
                         "Unsupported property: {}:{}", n, v.iter().to_css()).as_slice()),
+                    ExperimentalProperty => log_css_error(l, format!(
+                        "Experimental property, use `servo --enable_experimental` \
+                         or `servo -e` to enable: {}:{}",
+                        n, v.iter().to_css()).as_slice()),
                     InvalidValue => log_css_error(l, format!(
                         "Invalid value: {}:{}", n, v.iter().to_css()).as_slice()),
                     ValidOrIgnoredDeclaration => (),
@@ -1486,6 +1494,7 @@ pub enum PropertyDeclaration {
 
 pub enum PropertyDeclarationParseResult {
     UnknownProperty,
+    ExperimentalProperty,
     InvalidValue,
     ValidOrIgnoredDeclaration,
 }
@@ -1502,6 +1511,11 @@ impl PropertyDeclaration {
             % for property in LONGHANDS:
                 % if property.derived_from is None:
                     "${property.name}" => {
+                        % if property.experimental:
+                            if !::servo_util::opts::experimental_enabled() {
+                                return ExperimentalProperty
+                            }
+                        % endif
                         if seen.get_${property.ident}() {
                             return ValidOrIgnoredDeclaration
                         }

src/components/util/opts.rs

@@ -45,10 +45,13 @@ pub struct Opts {
     /// cause it to produce output on that interval (`-p`).
     pub time_profiler_period: Option<f64>,
 
-    /// `None` to disable the memory profiler or `Some` with an interval in seconds to enable it 
+    /// `None` to disable the memory profiler or `Some` with an interval in seconds to enable it
     /// and cause it to produce output on that interval (`-m`).
     pub memory_profiler_period: Option<f64>,
 
+    /// Enable experimental web features (`-e`).
+    pub enable_experimental: bool,
+
     /// The number of threads to use for layout (`-y`). Defaults to 1, which results in a recursive
     /// sequential algorithm.
     pub layout_threads: uint,
@@ -87,6 +90,7 @@ pub fn from_cmdline_args(args: &[String]) -> Option<Opts> {
         getopts::optopt("r", "rendering", "Rendering backend", "direct2d|core-graphics|core-graphics-accelerated|cairo|skia."),
         getopts::optopt("s", "size", "Size of tiles", "512"),
         getopts::optopt("", "device-pixel-ratio", "Device pixels per px", ""),
+        getopts::optflag("e", "experimental", "Enable experimental web features"),
         getopts::optopt("t", "threads", "Number of render threads", "1"),
         getopts::optflagopt("p", "profile", "Profiler flag and output interval", "10"),
         getopts::optflagopt("m", "memory-profile", "Memory profiler flag and output interval", "10"),
@@ -176,6 +180,7 @@ pub fn from_cmdline_args(args: &[String]) -> Option<Opts> {
         device_pixels_per_px: device_pixels_per_px,
         time_profiler_period: time_profiler_period,
         memory_profiler_period: memory_profiler_period,
+        enable_experimental: opt_match.opt_present("e"),
         layout_threads: layout_threads,
         exit_after_load: opt_match.opt_present("x"),
         output_file: opt_match.opt_str("o"),
@@ -184,3 +189,17 @@ pub fn from_cmdline_args(args: &[String]) -> Option<Opts> {
         bubble_widths_separately: opt_match.opt_present("b"),
     })
 }
+
+static mut EXPERIMENTAL_ENABLED: bool = false;
+
+pub fn set_experimental_enabled(new_value: bool) {
+    unsafe {
+        EXPERIMENTAL_ENABLED = new_value;
+    }
+}
+
+pub fn experimental_enabled() -> bool {
+    unsafe {
+        EXPERIMENTAL_ENABLED
+    }
+}