From 71ac7ba47456d52d968ade8bfbfffcc22700db71 Mon Sep 17 00:00:00 2001
From: Jonathan Kew <jkew@mozilla.com>
Date: Wed, 22 Sep 2021 18:48:53 +0000
Subject: [PATCH] Bug 1719544 - part 2 - Convert gfxHarfBuzzShaper
 normalization callbacks from direct ICU access to mozilla::intl::String APIs.
 r=platform-i18n-reviewers,dminor

Depends on D126259

Differential Revision: https://phabricator.services.mozilla.com/D126260
---
 gfx/thebes/gfxHarfBuzzShaper.cpp | 57 ++++++++------------------------
 1 file changed, 13 insertions(+), 44 deletions(-)

diff --git a/gfx/thebes/gfxHarfBuzzShaper.cpp b/gfx/thebes/gfxHarfBuzzShaper.cpp
index adc84f814fa8..2fe44e7656f0 100644
--- a/gfx/thebes/gfxHarfBuzzShaper.cpp
+++ b/gfx/thebes/gfxHarfBuzzShaper.cpp
@@ -10,17 +10,13 @@
 #include "gfxFontUtils.h"
 #include "gfxTextRun.h"
 #include "mozilla/Sprintf.h"
+#include "mozilla/intl/String.h"
 #include "nsUnicodeProperties.h"
 #include "nsUnicodeScriptCodes.h"
 
 #include "harfbuzz/hb.h"
 #include "harfbuzz/hb-ot.h"
 
-#include "unicode/unorm.h"
-#include "unicode/utext.h"
-
-static const UNormalizer2* sNormalizer = nullptr;
-
 #include <algorithm>
 
 #define FloatToFixed(f) (65536 * (f))
@@ -1038,12 +1034,10 @@ static const char16_t sDageshForms[0x05EA - 0x05D0 + 1] = {
 static hb_bool_t HBUnicodeCompose(hb_unicode_funcs_t* ufuncs, hb_codepoint_t a,
                                   hb_codepoint_t b, hb_codepoint_t* ab,
                                   void* user_data) {
-  if (sNormalizer) {
-    UChar32 ch = unorm2_composePair(sNormalizer, a, b);
-    if (ch >= 0) {
-      *ab = ch;
-      return true;
-    }
+  char32_t ch = mozilla::intl::String::ComposePairNFC(a, b);
+  if (ch > 0) {
+    *ab = ch;
+    return true;
   }
 
   return false;
@@ -1062,37 +1056,16 @@ static hb_bool_t HBUnicodeDecompose(hb_unicode_funcs_t* ufuncs,
   }
 #endif
 
-  if (!sNormalizer) {
-    return false;
+  char32_t decomp[2] = {0};
+  if (mozilla::intl::String::DecomposeRawNFD(ab, decomp)) {
+    if (decomp[1] || decomp[0] != ab) {
+      *a = decomp[0];
+      *b = decomp[1];
+      return true;
+    }
   }
 
-  // Canonical decompositions are never more than two characters,
-  // or a maximum of 4 utf-16 code units.
-  const unsigned MAX_DECOMP_LENGTH = 4;
-
-  UErrorCode error = U_ZERO_ERROR;
-  UChar decomp[MAX_DECOMP_LENGTH];
-  int32_t len = unorm2_getRawDecomposition(sNormalizer, ab, decomp,
-                                           MAX_DECOMP_LENGTH, &error);
-  if (U_FAILURE(error) || len < 0) {
-    return false;
-  }
-
-  UText text = UTEXT_INITIALIZER;
-  utext_openUChars(&text, decomp, len, &error);
-  NS_ASSERTION(U_SUCCESS(error), "UText failure?");
-
-  UChar32 ch = UTEXT_NEXT32(&text);
-  if (ch != U_SENTINEL) {
-    *a = ch;
-  }
-  ch = UTEXT_NEXT32(&text);
-  if (ch != U_SENTINEL) {
-    *b = ch;
-  }
-  utext_close(&text);
-
-  return *b != 0 || *a != ab;
+  return false;
 }
 
 static void AddOpenTypeFeature(const uint32_t& aTag, uint32_t& aValue,
@@ -1164,10 +1137,6 @@ bool gfxHarfBuzzShaper::Initialize() {
     hb_unicode_funcs_set_decompose_func(sHBUnicodeFuncs, HBUnicodeDecompose,
                                         nullptr, nullptr);
     hb_unicode_funcs_make_immutable(sHBUnicodeFuncs);
-
-    UErrorCode error = U_ZERO_ERROR;
-    sNormalizer = unorm2_getNFCInstance(&error);
-    MOZ_ASSERT(U_SUCCESS(error), "failed to get ICU normalizer");
   }
 
   gfxFontEntry* entry = mFont->GetFontEntry();