moebius#90: CSS - implement text-justify property

26 files changed, 312 insertions, 9 deletions

diff --git a/devtools/shared/css/generated/properties-db.js b/devtools/shared/css/generated/properties-db.js
index 83b3efafc4..0701674967 100644
--- a/devtools/shared/css/generated/properties-db.js
+++ b/devtools/shared/css/generated/properties-db.js
@@ -3064,6 +3064,7 @@ exports.CSS_PROPERTIES = {
       "text-emphasis-style",
       "-webkit-text-fill-color",
       "text-indent",
+      "text-justify",
       "text-orientation",
       "text-overflow",
       "text-rendering",
@@ -3240,6 +3241,7 @@ exports.CSS_PROPERTIES = {
       "dialog",
       "difference",
       "disabled",
+      "distribute",
       "dotted",
       "double",
       "drag",
@@ -3299,6 +3301,8 @@ exports.CSS_PROPERTIES = {
       "inline-table",
       "inset",
       "inside",
+      "inter-character",
+      "inter-word",
       "intersect",
       "isolate",
       "italic",
@@ -8865,6 +8869,23 @@ exports.CSS_PROPERTIES = {
       "unset"
     ]
   },
+  "text-justify": {
+    "isInherited": true,
+    "subproperties": [
+      "text-justify"
+    ],
+    "supports": [],
+    "values": [
+      "auto",
+      "distribute",
+      "inherit",
+      "initial",
+      "inter-character",
+      "inter-word",
+      "none",
+      "unset"
+    ]
+  },
   "text-orientation": {
     "isInherited": true,
     "subproperties": [
diff --git a/layout/base/nsLayoutUtils.cpp b/layout/base/nsLayoutUtils.cpp
index c8c91b251c..86874f4041 100644
--- a/layout/base/nsLayoutUtils.cpp
+++ b/layout/base/nsLayoutUtils.cpp
@@ -7013,7 +7013,8 @@ nsLayoutUtils::GetTextRunFlagsForStyle(nsStyleContext* aStyleContext,
                                        nscoord aLetterSpacing)
 {
   uint32_t result = 0;
-  if (aLetterSpacing != 0) {
+  if (aLetterSpacing != 0 ||
+      aStyleText->mTextJustify == StyleTextJustify::InterCharacter) {
     result |= gfxTextRunFactory::TEXT_DISABLE_OPTIONAL_LIGATURES;
   }
   if (aStyleText->mControlCharacterVisibility == NS_STYLE_CONTROL_CHARACTER_VISIBILITY_HIDDEN) {
diff --git a/layout/generic/nsTextFrame.cpp b/layout/generic/nsTextFrame.cpp
index 00c0016fd1..fa31443fdd 100644
--- a/layout/generic/nsTextFrame.cpp
+++ b/layout/generic/nsTextFrame.cpp
@@ -2936,22 +2936,40 @@ nsTextFrame::GetTrimmedOffsets(const nsTextFragment* aFrag,
   return offsets;
 }
 
-static bool IsJustifiableCharacter(const nsTextFragment* aFrag, int32_t aPos,
+static bool IsJustifiableCharacter(const nsStyleText* aTextStyle,
+                                   const nsTextFragment* aFrag, int32_t aPos,
                                    bool aLangIsCJ)
 {
   NS_ASSERTION(aPos >= 0, "negative position?!");
+
+  StyleTextJustify justifyStyle = aTextStyle->mTextJustify;
+  if (justifyStyle == StyleTextJustify::None) {
+    return false;
+  }
+
   char16_t ch = aFrag->CharAt(aPos);
-  if (ch == '\n' || ch == '\t' || ch == '\r')
+  if (ch == '\n' || ch == '\t' || ch == '\r') {
     return true;
+  }
   if (ch == ' ' || ch == CH_NBSP) {
     // Don't justify spaces that are combined with diacriticals
-    if (!aFrag->Is2b())
+    if (!aFrag->Is2b()) {
       return true;
+    }
     return !nsTextFrameUtils::IsSpaceCombiningSequenceTail(
-        aFrag->Get2b() + aPos + 1, aFrag->GetLength() - (aPos + 1));
+      aFrag->Get2b() + aPos + 1, aFrag->GetLength() - (aPos + 1));
   }
-  if (ch < 0x2150u)
+
+  if (justifyStyle == StyleTextJustify::InterCharacter) {
+    return true;
+  } else if (justifyStyle == StyleTextJustify::InterWord) {
+    return false;
+  }
+
+  // text-justify: auto
+  if (ch < 0x2150u) {
     return false;
+  }
   if (aLangIsCJ) {
     if ((0x2150u <= ch && ch <= 0x22ffu) || // Number Forms, Arrows, Mathematical Operators
         (0x2460u <= ch && ch <= 0x24ffu) || // Enclosed Alphanumerics
@@ -3279,7 +3297,7 @@ PropertyProvider::ComputeJustification(
     gfxSkipCharsIterator iter = run.GetPos();
     for (uint32_t i = 0; i < length; ++i) {
       uint32_t offset = originalOffset + i;
-      if (!IsJustifiableCharacter(mFrag, offset, isCJ)) {
+      if (!IsJustifiableCharacter(mTextStyle, mFrag, offset, isCJ)) {
         continue;
       }
 
diff --git a/layout/reftests/w3c-css/submitted/check-for-references.sh b/layout/reftests/w3c-css/submitted/check-for-references.sh
index 977cee3f48..c30e185152 100755
--- a/layout/reftests/w3c-css/submitted/check-for-references.sh
+++ b/layout/reftests/w3c-css/submitted/check-for-references.sh
@@ -15,7 +15,7 @@ do
         else
             echo "Unexpected type $TYPE for $DIRNAME/$TEST"
         fi
-        if grep "rel=\"$REFTYPE\"" "$DIRNAME/$TEST" | head -1 | grep -q "href=\"$REF\""
+        if grep "rel=\(\"$REFTYPE\"\|'$REFTYPE'\)" "$DIRNAME/$TEST" | head -1 | grep -q "href=\(\"$REF\"\|'$REF'\)"
         then
             #echo "Good link for $DIRNAME/$TEST"
             echo -n
diff --git a/layout/reftests/w3c-css/submitted/text3/reftest.list b/layout/reftests/w3c-css/submitted/text3/reftest.list
index 2712e4363b..a1e3d70d0c 100644
--- a/layout/reftests/w3c-css/submitted/text3/reftest.list
+++ b/layout/reftests/w3c-css/submitted/text3/reftest.list
@@ -5,4 +5,9 @@
 == text-align-match-parent-root-ltr.html text-align-match-parent-root-ltr-ref.html
 == text-align-match-parent-root-rtl.html text-align-match-parent-root-rtl-ref.html
 
+pref(layout.css.text-justify.enabled,true) == text-justify-none-001.html text-justify-none-001-ref.html
+pref(layout.css.text-justify.enabled,true) == text-justify-inter-word-001.html text-justify-inter-word-001-ref.html
+pref(layout.css.text-justify.enabled,true) == text-justify-inter-character-001.html text-justify-inter-character-001-ref.html
+pref(layout.css.text-justify.enabled,true) == text-justify-distribute-001.html text-justify-inter-character-001-ref.html
+
 == text-word-spacing-001.html text-word-spacing-ref.html
diff --git a/layout/reftests/w3c-css/submitted/text3/text-justify-distribute-001.html b/layout/reftests/w3c-css/submitted/text3/text-justify-distribute-001.html
new file mode 100644
index 0000000000..4d29f0fee5
--- /dev/null
+++ b/layout/reftests/w3c-css/submitted/text3/text-justify-distribute-001.html
@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Text 7.4. Justification Method: text-justify: distribute</title>
+<link rel="author" title="Chun-Min (Jeremy) Chen" href="mailto:jeremychen@mozilla.com">
+<link rel="author" title="Mozilla" href="https://www.mozilla.org">
+<link rel="help" href="https://drafts.csswg.org/css-text-3/#text-justify-property">
+<link rel='match' href='text-justify-inter-character-001-ref.html'>
+<meta name="assert" content="text-justify:distribute means justification adjusts spacing between each pair of adjacent typographic character units.">
+<style type='text/css'>
+p {
+  font-size: 1.5em;
+  border: 1px solid black;
+  padding: 10px;
+  margin-right: 310px;
+}
+.test {
+  text-align-last: justify;
+  text-justify: distribute;
+}
+</style>
+</head>
+<body>
+<p lang="en" class="test">XX</p>
+<p lang="ja" class="test">文字</p>
+</body>
+</html>
diff --git a/layout/reftests/w3c-css/submitted/text3/text-justify-inter-character-001-ref.html b/layout/reftests/w3c-css/submitted/text3/text-justify-inter-character-001-ref.html
new file mode 100644
index 0000000000..0a42a5cf8c
--- /dev/null
+++ b/layout/reftests/w3c-css/submitted/text3/text-justify-inter-character-001-ref.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Text 7.4. Justification Method: text-justify: inter-character</title>
+<link rel="author" title="Chun-Min (Jeremy) Chen" href="mailto:jeremychen@mozilla.com">
+<link rel="author" title="Mozilla" href="https://www.mozilla.org">
+<style type='text/css'>
+p {
+  font-size: 1.5em;
+  border: 1px solid black;
+  padding: 10px;
+  margin-right: 310px;
+}
+.right {
+  float: right;
+}
+</style>
+</head>
+<body>
+<p lang="en">X<span class="right">X</span></p>
+<p lang="ja">文<span class="right">字</span></p>
+</body>
+</html>
diff --git a/layout/reftests/w3c-css/submitted/text3/text-justify-inter-character-001.html b/layout/reftests/w3c-css/submitted/text3/text-justify-inter-character-001.html
new file mode 100644
index 0000000000..639ab7ecb7
--- /dev/null
+++ b/layout/reftests/w3c-css/submitted/text3/text-justify-inter-character-001.html
@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Text 7.4. Justification Method: text-justify: inter-character</title>
+<link rel="author" title="Chun-Min (Jeremy) Chen" href="mailto:jeremychen@mozilla.com">
+<link rel="author" title="Mozilla" href="https://www.mozilla.org">
+<link rel="help" href="https://drafts.csswg.org/css-text-3/#text-justify-property">
+<link rel='match' href='text-justify-inter-character-001-ref.html'>
+<meta name="assert" content="text-justify:inter-character means justification adjusts spacing between each pair of adjacent typographic character units.">
+<style type='text/css'>
+p {
+  font-size: 1.5em;
+  border: 1px solid black;
+  padding: 10px;
+  margin-right: 310px;
+}
+.test {
+  text-align-last: justify;
+  text-justify: inter-character;
+}
+</style>
+</head>
+<body>
+<p lang="en" class="test">XX</p>
+<p lang="ja" class="test">文字</p>
+</body>
+</html>
diff --git a/layout/reftests/w3c-css/submitted/text3/text-justify-inter-word-001-ref.html b/layout/reftests/w3c-css/submitted/text3/text-justify-inter-word-001-ref.html
new file mode 100644
index 0000000000..687e864e7d
--- /dev/null
+++ b/layout/reftests/w3c-css/submitted/text3/text-justify-inter-word-001-ref.html
@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Text 7.4. Justification Method: text-justify: inter-word</title>
+<link rel="author" title="Chun-Min (Jeremy) Chen" href="mailto:jeremychen@mozilla.com">
+<link rel="author" title="Mozilla" href="https://www.mozilla.org">
+<style type='text/css'>
+p {
+  font-size: 1.5em;
+  border: 1px solid black;
+  padding: 10px;
+  margin-right: 310px;
+}
+.right {
+  float: right;
+}
+</style>
+</head>
+<body>
+<p lang="en">Latin<span class="right">text</span></p>
+<p lang="ja">日本<span class="right">文字</span></p>
+<p lang="th">อักษรไทย<span class="right">อักษรไทย</span></p>
+</body>
+</html>
diff --git a/layout/reftests/w3c-css/submitted/text3/text-justify-inter-word-001.html b/layout/reftests/w3c-css/submitted/text3/text-justify-inter-word-001.html
new file mode 100644
index 0000000000..75aec2f5f6
--- /dev/null
+++ b/layout/reftests/w3c-css/submitted/text3/text-justify-inter-word-001.html
@@ -0,0 +1,29 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Text 7.4. Justification Method: text-justify: inter-word</title>
+<link rel="author" title="Chun-Min (Jeremy) Chen" href="mailto:jeremychen@mozilla.com">
+<link rel="author" title="Mozilla" href="https://www.mozilla.org">
+<link rel="help" href="https://drafts.csswg.org/css-text-3/#text-justify-property">
+<link rel='match' href='text-justify-inter-word-001-ref.html'>
+<meta name="assert" content="text-justify:inter-word means justification adjusts spacing at word separators only.">
+<style type='text/css'>
+p {
+  font-size: 1.5em;
+  border: 1px solid black;
+  padding: 10px;
+  margin-right: 310px;
+}
+.test {
+  text-align-last: justify;
+  text-justify: inter-word;
+}
+</style>
+</head>
+<body>
+<p lang="en" class="test">Latin text</p>
+<p lang="ja" class="test">日本 文字</p>
+<p lang="th" class="test">อักษรไทย อักษรไทย</p>
+</body>
+</html>
diff --git a/layout/reftests/w3c-css/submitted/text3/text-justify-none-001-ref.html b/layout/reftests/w3c-css/submitted/text3/text-justify-none-001-ref.html
new file mode 100644
index 0000000000..c8500ac9f3
--- /dev/null
+++ b/layout/reftests/w3c-css/submitted/text3/text-justify-none-001-ref.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Text 7.4. Justification Method: text-justify: none</title>
+<link rel="author" title="Chun-Min (Jeremy) Chen" href="mailto:jeremychen@mozilla.com">
+<link rel="author" title="Mozilla" href="https://www.mozilla.org">
+<style type='text/css'>
+p {
+  font-size: 1.5em;
+  border: 1px solid black;
+  padding: 10px;
+  margin-right: 310px;
+}
+</style>
+</head>
+<body>
+<p lang="en">Latin text</p>
+<p lang="ja">日本 文字</p>
+<p lang="th">อักษรไทย อักษรไทย</p>
+</body>
+</html>
diff --git a/layout/reftests/w3c-css/submitted/text3/text-justify-none-001.html b/layout/reftests/w3c-css/submitted/text3/text-justify-none-001.html
new file mode 100644
index 0000000000..2b55111954
--- /dev/null
+++ b/layout/reftests/w3c-css/submitted/text3/text-justify-none-001.html
@@ -0,0 +1,29 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Text 7.4. Justification Method: text-justify: none</title>
+<link rel="author" title="Chun-Min (Jeremy) Chen" href="mailto:jeremychen@mozilla.com">
+<link rel="author" title="Mozilla" href="https://www.mozilla.org">
+<link rel="help" href="https://drafts.csswg.org/css-text-3/#text-justify-property">
+<link rel='match' href='text-justify-none-001-ref.html'>
+<meta name="assert" content="text-justify:none means justification is disabled: there are no justification opportunities within the text.">
+<style type='text/css'>
+p {
+  font-size: 1.5em;
+  border: 1px solid black;
+  padding: 10px;
+  margin-right: 310px;
+}
+.test {
+  text-align-last: justify;
+  text-justify: none;
+}
+</style>
+</head>
+<body>
+<p lang="en" class="test">Latin text</p>
+<p lang="ja" class="test">日本 文字</p>
+<p lang="th" class="test">อักษรไทย อักษรไทย</p>
+</body>
+</html>
diff --git a/layout/style/nsCSSKeywordList.h b/layout/style/nsCSSKeywordList.h
index 933ff6e7b6..94968faca3 100644
--- a/layout/style/nsCSSKeywordList.h
+++ b/layout/style/nsCSSKeywordList.h
@@ -238,6 +238,7 @@ CSS_KEY(disc, disc)
 CSS_KEY(disclosure-closed, disclosure_closed)
 CSS_KEY(disclosure-open, disclosure_open)
 CSS_KEY(discretionary-ligatures, discretionary_ligatures)
+CSS_KEY(distribute, distribute)
 CSS_KEY(dot, dot)
 CSS_KEY(dotted, dotted)
 CSS_KEY(double, double)
@@ -333,7 +334,8 @@ CSS_KEY(inline-start, inline_start)
 CSS_KEY(inline-table, inline_table)
 CSS_KEY(inset, inset)
 CSS_KEY(inside, inside)
-// CSS_KEY(inter-character, inter_character) // TODO see bug 1055672
+CSS_KEY(inter-character, inter_character)
+CSS_KEY(inter-word, inter_word)
 CSS_KEY(interpolatematrix, interpolatematrix)
 CSS_KEY(intersect, intersect)
 CSS_KEY(isolate, isolate)
diff --git a/layout/style/nsCSSPropList.h b/layout/style/nsCSSPropList.h
index 6931d8c2b4..b04921dcb5 100644
--- a/layout/style/nsCSSPropList.h
+++ b/layout/style/nsCSSPropList.h
@@ -4027,6 +4027,17 @@ CSS_PROP_TEXT(
     nullptr,
     offsetof(nsStyleText, mTextIndent),
     eStyleAnimType_Coord)
+CSS_PROP_TEXT(
+    text-justify,
+    text_justify,
+    TextJustify,
+    CSS_PROPERTY_PARSE_VALUE |
+        CSS_PROPERTY_APPLIES_TO_PLACEHOLDER,
+    "layout.css.text-justify.enabled",
+    VARIANT_HK,
+    kTextJustifyKTable,
+    CSS_PROP_NO_OFFSET,
+    eStyleAnimType_Discrete)
 CSS_PROP_VISIBILITY(
     text-orientation,
     text_orientation,
diff --git a/layout/style/nsCSSProps.cpp b/layout/style/nsCSSProps.cpp
index f3a7f898de..9805eae14e 100644
--- a/layout/style/nsCSSProps.cpp
+++ b/layout/style/nsCSSProps.cpp
@@ -2035,6 +2035,17 @@ KTableEntry nsCSSProps::kTextAlignLastKTable[] = {
   { eCSSKeyword_UNKNOWN, -1 }
 };
 
+const KTableEntry nsCSSProps::kTextJustifyKTable[] = {
+  { eCSSKeyword_none, StyleTextJustify::None },
+  { eCSSKeyword_auto, StyleTextJustify::Auto },
+  { eCSSKeyword_inter_word, StyleTextJustify::InterWord },
+  { eCSSKeyword_inter_character, StyleTextJustify::InterCharacter },
+  // For legacy reasons, UAs must also support the keyword "distribute" with
+  // the exact same meaning and behavior as "inter-character".
+  { eCSSKeyword_distribute, StyleTextJustify::InterCharacter },
+  { eCSSKeyword_UNKNOWN, -1 }
+};
+
 const KTableEntry nsCSSProps::kTextCombineUprightKTable[] = {
   { eCSSKeyword_none, NS_STYLE_TEXT_COMBINE_UPRIGHT_NONE },
   { eCSSKeyword_all, NS_STYLE_TEXT_COMBINE_UPRIGHT_ALL },
diff --git a/layout/style/nsCSSProps.h b/layout/style/nsCSSProps.h
index ab78e61741..dfe35afd82 100644
--- a/layout/style/nsCSSProps.h
+++ b/layout/style/nsCSSProps.h
@@ -869,6 +869,7 @@ public:
   static const KTableEntry kTextEmphasisPositionKTable[];
   static const KTableEntry kTextEmphasisStyleFillKTable[];
   static const KTableEntry kTextEmphasisStyleShapeKTable[];
+  static const KTableEntry kTextJustifyKTable[];
   static const KTableEntry kTextOrientationKTable[];
   static const KTableEntry kTextOverflowKTable[];
   static const KTableEntry kTextTransformKTable[];
diff --git a/layout/style/nsComputedDOMStyle.cpp b/layout/style/nsComputedDOMStyle.cpp
index 4eb24b76b9..4f8d3edf66 100644
--- a/layout/style/nsComputedDOMStyle.cpp
+++ b/layout/style/nsComputedDOMStyle.cpp
@@ -3875,6 +3875,16 @@ nsComputedDOMStyle::DoGetTextIndent()
 }
 
 already_AddRefed<CSSValue>
+nsComputedDOMStyle::DoGetTextJustify()
+{
+  RefPtr<nsROCSSPrimitiveValue> val = new nsROCSSPrimitiveValue;
+  val->SetIdent(
+    nsCSSProps::ValueToKeywordEnum(StyleText()->mTextJustify,
+                                   nsCSSProps::kTextJustifyKTable));
+  return val.forget();
+}
+
+already_AddRefed<CSSValue>
 nsComputedDOMStyle::DoGetTextOrientation()
 {
   RefPtr<nsROCSSPrimitiveValue> val = new nsROCSSPrimitiveValue;
diff --git a/layout/style/nsComputedDOMStyle.h b/layout/style/nsComputedDOMStyle.h
index 223b29a141..27e2086e92 100644
--- a/layout/style/nsComputedDOMStyle.h
+++ b/layout/style/nsComputedDOMStyle.h
@@ -421,6 +421,7 @@ private:
   already_AddRefed<CSSValue> DoGetTextEmphasisPosition();
   already_AddRefed<CSSValue> DoGetTextEmphasisStyle();
   already_AddRefed<CSSValue> DoGetTextIndent();
+  already_AddRefed<CSSValue> DoGetTextJustify();
   already_AddRefed<CSSValue> DoGetTextOrientation();
   already_AddRefed<CSSValue> DoGetTextOverflow();
   already_AddRefed<CSSValue> DoGetTextTransform();
diff --git a/layout/style/nsComputedDOMStylePropertyList.h b/layout/style/nsComputedDOMStylePropertyList.h
index 7c0457e342..1983208acc 100644
--- a/layout/style/nsComputedDOMStylePropertyList.h
+++ b/layout/style/nsComputedDOMStylePropertyList.h
@@ -239,6 +239,7 @@ COMPUTED_STYLE_PROP(text_emphasis_color,           TextEmphasisColor)
 COMPUTED_STYLE_PROP(text_emphasis_position,        TextEmphasisPosition)
 COMPUTED_STYLE_PROP(text_emphasis_style,           TextEmphasisStyle)
 COMPUTED_STYLE_PROP(text_indent,                   TextIndent)
+COMPUTED_STYLE_PROP(text_justify,                  TextJustify)
 COMPUTED_STYLE_PROP(text_orientation,              TextOrientation)
 COMPUTED_STYLE_PROP(text_overflow,                 TextOverflow)
 COMPUTED_STYLE_PROP(text_shadow,                   TextShadow)
diff --git a/layout/style/nsRuleNode.cpp b/layout/style/nsRuleNode.cpp
index fa29fe0f17..9b9fc3948e 100644
--- a/layout/style/nsRuleNode.cpp
+++ b/layout/style/nsRuleNode.cpp
@@ -1414,6 +1414,7 @@ struct SetEnumValueHelper
   DEFINE_ENUM_CLASS_SETTER(StyleFillRule, Nonzero, Evenodd)
   DEFINE_ENUM_CLASS_SETTER(StyleFloat, None, InlineEnd)
   DEFINE_ENUM_CLASS_SETTER(StyleFloatEdge, ContentBox, MarginBox)
+  DEFINE_ENUM_CLASS_SETTER(StyleTextJustify, None, InterCharacter)
   DEFINE_ENUM_CLASS_SETTER(StyleUserFocus, None, SelectMenu)
   DEFINE_ENUM_CLASS_SETTER(StyleUserSelect, None, MozText)
   DEFINE_ENUM_CLASS_SETTER(StyleUserInput, None, Auto)
@@ -4783,6 +4784,12 @@ nsRuleNode::ComputeTextData(void* aStartStruct,
              SETCOORD_UNSET_INHERIT,
            aContext, mPresContext, conditions);
 
+  // text-justify: enum, inherit, initial
+  SetValue(*aRuleData->ValueForTextJustify(), text->mTextJustify, conditions,
+           SETVAL_ENUMERATED | SETVAL_UNSET_INHERIT,
+           parentText->mTextJustify,
+           StyleTextJustify::Auto);
+
   // text-transform: enum, inherit, initial
   SetValue(*aRuleData->ValueForTextTransform(), text->mTextTransform, conditions,
            SETVAL_ENUMERATED | SETVAL_UNSET_INHERIT,
diff --git a/layout/style/nsStyleConsts.h b/layout/style/nsStyleConsts.h
index ee78dcb64d..be588113e9 100644
--- a/layout/style/nsStyleConsts.h
+++ b/layout/style/nsStyleConsts.h
@@ -185,6 +185,14 @@ enum class StyleShapeSourceType : uint8_t {
   Box,
 };
 
+// text-justify
+enum class StyleTextJustify : uint8_t {
+  None,
+  Auto,
+  InterWord,
+  InterCharacter,
+};
+
 // user-focus
 enum class StyleUserFocus : uint8_t {
   None,
diff --git a/layout/style/nsStyleStruct.cpp b/layout/style/nsStyleStruct.cpp
index 2f12d62018..68ae88d249 100644
--- a/layout/style/nsStyleStruct.cpp
+++ b/layout/style/nsStyleStruct.cpp
@@ -3797,6 +3797,7 @@ nsStyleText::nsStyleText(StyleStructContext aContext)
   , mTextAlignLast(NS_STYLE_TEXT_ALIGN_AUTO)
   , mTextAlignTrue(false)
   , mTextAlignLastTrue(false)
+  , mTextJustify(StyleTextJustify::Auto)
   , mTextTransform(NS_STYLE_TEXT_TRANSFORM_NONE)
   , mWhiteSpace(NS_STYLE_WHITESPACE_NORMAL)
   , mWordBreak(NS_STYLE_WORDBREAK_NORMAL)
@@ -3833,6 +3834,7 @@ nsStyleText::nsStyleText(const nsStyleText& aSource)
   , mTextAlignLast(aSource.mTextAlignLast)
   , mTextAlignTrue(false)
   , mTextAlignLastTrue(false)
+  , mTextJustify(aSource.mTextJustify)
   , mTextTransform(aSource.mTextTransform)
   , mWhiteSpace(aSource.mWhiteSpace)
   , mWordBreak(aSource.mWordBreak)
@@ -3894,6 +3896,7 @@ nsStyleText::CalcDifference(const nsStyleText& aNewData) const
       (mTextSizeAdjust != aNewData.mTextSizeAdjust) ||
       (mLetterSpacing != aNewData.mLetterSpacing) ||
       (mLineHeight != aNewData.mLineHeight) ||
+      (mTextJustify != aNewData.mTextJustify) ||
       (mTextIndent != aNewData.mTextIndent) ||
       (mWordSpacing != aNewData.mWordSpacing) ||
       (mTabSize != aNewData.mTabSize)) {
diff --git a/layout/style/nsStyleStruct.h b/layout/style/nsStyleStruct.h
index ca5d030566..41bb356a8b 100644
--- a/layout/style/nsStyleStruct.h
+++ b/layout/style/nsStyleStruct.h
@@ -2068,6 +2068,7 @@ struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleText
   uint8_t mTextAlignLast;               // [inherited] see nsStyleConsts.h
   bool mTextAlignTrue : 1;              // [inherited] see nsStyleConsts.h
   bool mTextAlignLastTrue : 1;          // [inherited] see nsStyleConsts.h
+  mozilla::StyleTextJustify mTextJustify;   // [inherited]
   uint8_t mTextTransform;               // [inherited] see nsStyleConsts.h
   uint8_t mWhiteSpace;                  // [inherited] see nsStyleConsts.h
   uint8_t mWordBreak;                   // [inherited] see nsStyleConsts.h
diff --git a/layout/style/test/property_database.js b/layout/style/test/property_database.js
index 62d413d983..272931c15e 100644
--- a/layout/style/test/property_database.js
+++ b/layout/style/test/property_database.js
@@ -5694,6 +5694,17 @@ if (IsCSSPropertyPrefEnabled("layout.css.text-combine-upright.enabled")) {
   }
 }
 
+if (IsCSSPropertyPrefEnabled("layout.css.text-justify.enabled")) {
+  gCSSProperties["text-justify"] = {
+    domProp: "textJustify",
+    inherited: true,
+    type: CSS_TYPE_LONGHAND,
+    initial_values: [ "auto" ],
+    other_values: [ "none", "inter-word", "inter-character", "distribute" ],
+    invalid_values: []
+  };
+}
+
 if (IsCSSPropertyPrefEnabled("svg.paint-order.enabled")) {
   gCSSProperties["paint-order"] = {
     domProp: "paintOrder",
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index ff47dc8e3b..689ef31c6a 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -2502,6 +2502,9 @@ pref("layout.css.convertFromNode.enabled", true);
 // Is support for CSS "text-align: unsafe X" enabled?
 pref("layout.css.text-align-unsafe-value.enabled", false);
 
+// Is support for CSS text-justify property enabled?
+pref("layout.css.text-justify.enabled", true);
+
 // Is support for CSS "float: inline-{start,end}" and
 // "clear: inline-{start,end}" enabled?
 #if defined(MOZ_B2G) || !defined(RELEASE_OR_BETA)
diff --git a/testing/profiles/prefs_general.js b/testing/profiles/prefs_general.js
index 91218b5f39..a9572b912b 100644
--- a/testing/profiles/prefs_general.js
+++ b/testing/profiles/prefs_general.js
@@ -181,6 +181,9 @@ user_pref("layout.css.prefixes.device-pixel-ratio-webkit", true);
 // Enable CSS shape-outside for testing
 user_pref("layout.css.shape-outside.enabled", true);
 
+// Enable CSS text-justify for testing
+user_pref("layout.css.text-justify.enabled", true);
+
 // Disable spammy layout warnings because they pollute test logs
 user_pref("layout.spammy_warnings.enabled", false);