From e45cb1544d03bb5b63cac61839dc3c4b42f046e0 Mon Sep 17 00:00:00 2001
From: Jonathan Kew <jkew@mozilla.com>
Date: Mon, 5 Sep 2016 14:15:32 +0100
Subject: [PATCH] Bug 1296050 - When checking whether bidi resolution is
 needed, ignore Unicode directional-control characters that do not actually
 introduce right-to-left-ness. r=xidorn

---
 dom/base/nsTextFragment.cpp         |  2 +-
 intl/unicharutil/util/nsBidiUtils.h | 23 +++++++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/dom/base/nsTextFragment.cpp b/dom/base/nsTextFragment.cpp
index 5473a615c738..260e254bed6b 100644
--- a/dom/base/nsTextFragment.cpp
+++ b/dom/base/nsTextFragment.cpp
@@ -461,7 +461,7 @@ nsTextFragment::UpdateBidiFlag(const char16_t* aBuffer, uint32_t aLength)
         char16_t ch2 = *cp++;
         utf32Char = SURROGATE_TO_UCS4(ch1, ch2);
       }
-      if (UTF32_CHAR_IS_BIDI(utf32Char) || IsBidiControl(utf32Char)) {
+      if (UTF32_CHAR_IS_BIDI(utf32Char) || IsBidiControlRTL(utf32Char)) {
         mState.mIsBidi = true;
         break;
       }
diff --git a/intl/unicharutil/util/nsBidiUtils.h b/intl/unicharutil/util/nsBidiUtils.h
index f002dd508a47..effe41861d68 100644
--- a/intl/unicharutil/util/nsBidiUtils.h
+++ b/intl/unicharutil/util/nsBidiUtils.h
@@ -111,10 +111,19 @@ typedef enum nsCharType nsCharType;
    * Return false, otherwise
    */
 #define LRM_CHAR 0x200e
+#define RLM_CHAR 0x200f
+
 #define LRE_CHAR 0x202a
+#define RLE_CHAR 0x202b
+#define PDF_CHAR 0x202c
+#define LRO_CHAR 0x202d
 #define RLO_CHAR 0x202e
+
 #define LRI_CHAR 0x2066
+#define RLI_CHAR 0x2067
+#define FSI_CHAR 0x2068
 #define PDI_CHAR 0x2069
+
 #define ALM_CHAR 0x061C
    inline bool IsBidiControl(uint32_t aChar) {
      return ((LRE_CHAR <= aChar && aChar <= RLO_CHAR) ||
@@ -123,6 +132,20 @@ typedef enum nsCharType nsCharType;
              (aChar & 0xfffffe) == LRM_CHAR);
    }
 
+  /**
+   * Give a UTF-32 codepoint
+   * Return true if the codepoint is a Bidi control character that may result
+   * in RTL directionality and therefore needs to trigger bidi resolution;
+   * return false otherwise.
+   */
+   inline bool IsBidiControlRTL(uint32_t aChar) {
+     return aChar == RLM_CHAR ||
+            aChar == RLE_CHAR ||
+            aChar == RLO_CHAR ||
+            aChar == RLI_CHAR ||
+            aChar == ALM_CHAR;
+   }
+
   /**
    * Give an nsString.
    * @return true if the string contains right-to-left characters