servo: Merge #12839 - Fix a cached style cascade bug that only manifested in sequential mode (from notriddle:11818_sequential_layout_bug); r=emilio

When copying cached styles, keep the `writing_mode` up to date.

---

- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #11818 (github issue number if applicable).
- [X] There are tests for these changes

EDIT: The test is now working. I ran it with the first commit (the actual fix) reverted and it failed.

Source-Repo: https://github.com/servo/servo
Source-Revision: 700bb911fcd8b34dcc5fbce22adcd8117cbf60d2

servo/components/constellation/pipeline.rs

@@ -162,7 +162,7 @@ impl Pipeline {
                     pipeline_port: pipeline_port,
                     layout_to_constellation_chan: state.layout_to_constellation_chan.clone(),
                     content_process_shutdown_chan: layout_content_process_shutdown_chan.clone(),
-                    layout_threads: opts::get().layout_threads,
+                    layout_threads: PREFS.get("layout.threads").as_u64().expect("count") as usize,
                 };
 
                 if let Err(e) = script_chan.send(ConstellationControlMsg::AttachLayout(new_layout_info)) {
@@ -474,7 +474,8 @@ impl UnprivilegedPipelineContent {
                     self.mem_profiler_chan,
                     self.layout_content_process_shutdown_chan,
                     self.webrender_api_sender,
-                    opts::get().layout_threads);
+                    self.prefs.get("layout.threads").expect("exists").value()
+                        .as_u64().expect("count") as usize);
 
         if wait_for_completion {
             let _ = self.script_content_process_shutdown_port.recv();

servo/components/style/properties/properties.mako.rs

@@ -1716,6 +1716,9 @@ fn cascade_with_cached_declarations(
         context.mutate_style().mutate_font().compute_font_hash();
     }
 
+    let mode = get_writing_mode(context.style.get_inheritedbox());
+    context.style.set_writing_mode(mode);
+
     context.style
 }
 

servo/components/util/opts.rs

@@ -55,10 +55,6 @@ pub struct Opts {
     /// and cause it to produce output on that interval (`-m`).
     pub mem_profiler_period: Option<f64>,
 
-    /// The number of threads to use for layout (`-y`). Defaults to 1, which results in a recursive
-    /// sequential algorithm.
-    pub layout_threads: usize,
-
     pub nonincremental_layout: bool,
 
     /// Where to load userscripts from, if any. An empty string will load from
@@ -481,7 +477,6 @@ pub fn default_opts() -> Opts {
         time_profiling: None,
         time_profiler_trace_path: None,
         mem_profiler_period: None,
-        layout_threads: 1,
         nonincremental_layout: false,
         userscripts: None,
         user_stylesheets: Vec::new(),
@@ -671,7 +666,7 @@ pub fn from_cmdline_args(args: &[String]) -> ArgumentParsingResult {
                 Ok(interval) => Some(OutputOptions::Stdout(interval)) ,
                 Err(_) => Some(OutputOptions::FileName(argument)),
             },
-            None => Some(OutputOptions::Stdout(5 as f64)),
+            None => Some(OutputOptions::Stdout(5.0 as f64)),
         }
     } else {
         // if the p option doesn't exist:
@@ -691,11 +686,11 @@ pub fn from_cmdline_args(args: &[String]) -> ArgumentParsingResult {
         period.parse().unwrap_or_else(|err| args_fail(&format!("Error parsing option: -m ({})", err)))
     });
 
-    let mut layout_threads: usize = match opt_match.opt_str("y") {
-        Some(layout_threads_str) => layout_threads_str.parse()
-            .unwrap_or_else(|err| args_fail(&format!("Error parsing option: -y ({})", err))),
-        None => cmp::max(num_cpus::get() * 3 / 4, 1),
-    };
+    let mut layout_threads: Option<usize> = opt_match.opt_str("y")
+        .map(|layout_threads_str| {
+            layout_threads_str.parse()
+                .unwrap_or_else(|err| args_fail(&format!("Error parsing option: -y ({})", err)))
+        });
 
     let nonincremental_layout = opt_match.opt_present("i");
 
@@ -714,7 +709,7 @@ pub fn from_cmdline_args(args: &[String]) -> ArgumentParsingResult {
     let mut bubble_inline_sizes_separately = debug_options.bubble_widths;
     if debug_options.trace_layout {
         paint_threads = 1;
-        layout_threads = 1;
+        layout_threads = Some(1);
         bubble_inline_sizes_separately = true;
     }
 
@@ -786,7 +781,6 @@ pub fn from_cmdline_args(args: &[String]) -> ArgumentParsingResult {
         time_profiling: time_profiling,
         time_profiler_trace_path: opt_match.opt_str("profiler-trace-path"),
         mem_profiler_period: mem_profiler_period,
-        layout_threads: layout_threads,
         nonincremental_layout: nonincremental_layout,
         userscripts: opt_match.opt_default("userscripts", ""),
         user_stylesheets: user_stylesheets,
@@ -855,6 +849,15 @@ pub fn from_cmdline_args(args: &[String]) -> ArgumentParsingResult {
         };
     }
 
+    if let Some(layout_threads) = layout_threads {
+        PREFS.set("layout.threads", PrefValue::Number(layout_threads as f64));
+    } else if let Some(layout_threads) = PREFS.get("layout.threads").as_string() {
+        PREFS.set("layout.threads", PrefValue::Number(layout_threads.parse::<f64>().unwrap()));
+    } else if *PREFS.get("layout.threads") == PrefValue::Missing {
+        let layout_threads = cmp::max(num_cpus::get() * 3 / 4, 1);
+        PREFS.set("layout.threads", PrefValue::Number(layout_threads as f64));
+    }
+
     ArgumentParsingResult::ChromeProcess
 }
 

servo/ports/cef/core.rs

@@ -69,7 +69,6 @@ pub extern "C" fn cef_initialize(args: *const cef_main_args_t,
 
     let mut temp_opts = opts::default_opts();
     temp_opts.paint_threads = rendering_threads;
-    temp_opts.layout_threads = rendering_threads;
     temp_opts.headless = false;
     temp_opts.hard_fail = false;
     temp_opts.enable_text_antialiasing = true;