Auto merge of #16779 - behnam:bidi-0.3, r=mbrubeck

[gfx] [layout] [style] Upgrade unicode-bidi to 0.3

Depends on https://github.com/servo/unicode-bidi/pull/27 , which
upgrades `unicode-bidi` crate to `0.3.0`.

Summary of changes:

* Use `unicode_bidi::Level` (instead of `u8`) in all relevant places and
replace magic computations with (inline) method calls to Level API.

* Doing so required adding `unicode-bidi` crate dependency to two more
components here: `style` and `gfx`. IMHO, totally makes sense, as
replaces local integer manipulations/checks with well-tested ones
already available in a common dependency.

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- [X] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable). [N/A]

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- [ ] There are tests for these changes OR
- [X] These changes do not require tests because `unicode-bidi` has its own tests and there's no logic change in this diff.

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components/layout/Cargo.toml

@@ -43,6 +43,6 @@ servo_url = {path = "../url"}
 smallvec = "0.3"
 style = {path = "../style"}
 style_traits = {path = "../style_traits"}
-unicode-bidi = "0.2"
+unicode-bidi = {version = "0.3", features = ["with_serde"]}
 unicode-script = {version = "0.1", features = ["harfbuzz"]}
 webrender_traits = {git = "https://github.com/servo/webrender", features = ["ipc"]}

components/layout/inline.rs

@@ -36,7 +36,7 @@ use style::logical_geometry::{LogicalRect, LogicalSize, WritingMode};
 use style::properties::{longhands, ServoComputedValues};
 use style::servo::restyle_damage::{BUBBLE_ISIZES, REFLOW, REFLOW_OUT_OF_FLOW, REPOSITION, RESOLVE_GENERATED_CONTENT};
 use text;
-use unicode_bidi;
+use unicode_bidi as bidi;
 
 /// `Line`s are represented as offsets into the child list, rather than
 /// as an object that "owns" fragments. Choosing a different set of line
@@ -95,7 +95,7 @@ pub struct Line {
     /// The bidirectional embedding level runs for this line, in visual order.
     ///
     /// Can be set to `None` if the line is 100% left-to-right.
-    pub visual_runs: Option<Vec<(Range<FragmentIndex>, u8)>>,
+    pub visual_runs: Option<Vec<(Range<FragmentIndex>, bidi::Level)>>,
 
     /// The bounds are the exact position and extents of the line with respect
     /// to the parent box.
@@ -293,22 +293,25 @@ impl LineBreaker {
         // (because we split fragments on level run boundaries during flow
         // construction), so we can build a level array with just one entry per
         // fragment.
-        let levels: Vec<u8> = self.new_fragments.iter().map(|fragment| match fragment.specific {
-            SpecificFragmentInfo::ScannedText(ref info) => info.run.bidi_level,
-            _ => para_level
-        }).collect();
+        let levels: Vec<bidi::Level> = self.new_fragments.iter().map(
+            |fragment| match fragment.specific {
+                SpecificFragmentInfo::ScannedText(ref info) => info.run.bidi_level,
+                _ => para_level
+            }
+        ).collect();
 
         let mut lines = mem::replace(&mut self.lines, Vec::new());
 
         // If everything is LTR, don't bother with reordering.
-        let has_rtl = levels.iter().cloned().any(unicode_bidi::is_rtl);
-
-        if has_rtl {
+        if bidi::level::has_rtl(&levels) {
             // Compute and store the visual ordering of the fragments within the
             // line.
             for line in &mut lines {
                 let range = line.range.begin().to_usize()..line.range.end().to_usize();
-                let runs = unicode_bidi::visual_runs(range, &levels);
+                // FIXME: Update to use BidiInfo::visual_runs, as this algorithm needs access to
+                // the original text and original BidiClass of its characters.
+                #[allow(deprecated)]
+                let runs = bidi::deprecated::visual_runs(range, &levels);
                 line.visual_runs = Some(runs.iter().map(|run| {
                     let start = FragmentIndex(run.start as isize);
                     let len = FragmentIndex(run.len() as isize);
@@ -957,11 +960,11 @@ impl InlineFlow {
             let (range, level) = match line.visual_runs {
                 Some(ref runs) if is_ltr => runs[run_idx],
                 Some(ref runs) => runs[run_count - run_idx - 1], // reverse order for RTL runs
-                None => (line.range, 0)
+                None => (line.range, bidi::Level::ltr())
             };
             // If the bidi embedding direction is opposite the layout direction, lay out this
             // run in reverse order.
-            let reverse = unicode_bidi::is_ltr(level) != is_ltr;
+            let reverse = level.is_ltr() != is_ltr;
             let fragment_indices = if reverse {
                 (range.end().get() - 1..range.begin().get() - 1).step_by(-1)
             } else {

components/layout/text.rs

@@ -28,7 +28,7 @@ use style::computed_values::{word_break, white_space};
 use style::logical_geometry::{LogicalSize, WritingMode};
 use style::properties::ServoComputedValues;
 use style::properties::style_structs;
-use unicode_bidi::{is_rtl, process_text};
+use unicode_bidi as bidi;
 use unicode_script::{Script, get_script};
 
 /// Returns the concatenated text of a list of unscanned text fragments.
@@ -74,10 +74,10 @@ impl TextRunScanner {
         // Calculate bidi embedding levels, so we can split bidirectional fragments for reordering.
         let text = text(&fragments);
         let para_level = fragments.front().unwrap().style.writing_mode.to_bidi_level();
-        let bidi_info = process_text(&text, Some(para_level));
+        let bidi_info = bidi::BidiInfo::new(&text, Some(para_level));
 
         // Optimization: If all the text is LTR, don't bother splitting on bidi levels.
-        let bidi_levels = if bidi_info.levels.iter().cloned().any(is_rtl) {
+        let bidi_levels = if bidi_info.has_rtl() {
             Some(&bidi_info.levels[..])
         } else {
             None
@@ -126,7 +126,7 @@ impl TextRunScanner {
                            font_context: &mut FontContext,
                            out_fragments: &mut Vec<Fragment>,
                            paragraph_bytes_processed: &mut usize,
-                           bidi_levels: Option<&[u8]>,
+                           bidi_levels: Option<&[bidi::Level]>,
                            mut last_whitespace: bool)
                            -> bool {
         debug!("TextRunScanner: flushing {} fragments in range", self.clump.len());
@@ -211,7 +211,7 @@ impl TextRunScanner {
 
                     let bidi_level = match bidi_levels {
                         Some(levels) => levels[*paragraph_bytes_processed],
-                        None => 0
+                        None => bidi::Level::ltr(),
                     };
 
                     // Break the run if the new character has a different explicit script than the
@@ -310,7 +310,7 @@ impl TextRunScanner {
             run_info_list.into_iter().map(|run_info| {
                 let mut options = options;
                 options.script = run_info.script;
-                if is_rtl(run_info.bidi_level) {
+                if run_info.bidi_level.is_rtl() {
                     options.flags.insert(RTL_FLAG);
                 }
                 let mut font = fontgroup.fonts.get(run_info.font_index).unwrap().borrow_mut();
@@ -522,7 +522,7 @@ struct RunInfo {
     /// The index of the applicable font in the font group.
     font_index: usize,
     /// The bidirection embedding level of this text run.
-    bidi_level: u8,
+    bidi_level: bidi::Level,
     /// The Unicode script property of this text run.
     script: Script,
 }
@@ -533,7 +533,7 @@ impl RunInfo {
             text: String::new(),
             insertion_point: None,
             font_index: 0,
-            bidi_level: 0,
+            bidi_level: bidi::Level::ltr(),
             script: Script::Common,
         }
     }