Clamp RunInfo::num_characters when shaping ranges with context

third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzShaperTest.cpp

 // Copyright (c) 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "platform/fonts/shaping/HarfBuzzShaper.h"
 
 #include <unicode/uscript.h>
 #include "platform/fonts/Font.h"
 #include "platform/fonts/FontCache.h"
 #include "platform/fonts/shaping/ShapeResultInlineHeaders.h"
@@ skipping 12 matching lines @@
     font = Font(font_description);
     font.Update(nullptr);
   }
 
   void TearDown() override {}
 
   FontCachePurgePreventer font_cache_purge_preventer;
   FontDescription font_description;
   Font font;
   unsigned start_index = 0;
+  unsigned num_characters = 0;
   unsigned num_glyphs = 0;
   hb_script_t script = HB_SCRIPT_INVALID;
 };
 
 static inline ShapeResultTestInfo* TestInfo(RefPtr<ShapeResult>& result) {
   return static_cast<ShapeResultTestInfo*>(result.Get());
 }
 
 static inline String To16Bit(const char* text, unsigned length) {
   return String::Make16BitFrom8BitSource(reinterpret_cast<const LChar*>(text),
@@ skipping 175 matching lines @@
 TEST_F(HarfBuzzShaperTest, ShapeLatinSegment) {
   String string = To16Bit("Hello World!", 12);
   TextDirection direction = TextDirection::kLtr;
 
   HarfBuzzShaper shaper(string.Characters16(), 12);
   RefPtr<ShapeResult> combined = shaper.Shape(&font, direction);
   RefPtr<ShapeResult> first = shaper.Shape(&font, direction, 0, 6);
   RefPtr<ShapeResult> second = shaper.Shape(&font, direction, 6, 11);
   RefPtr<ShapeResult> third = shaper.Shape(&font, direction, 11, 12);
 
+  ASSERT_TRUE(TestInfo(first)->RunInfoForTesting(0, start_index, num_characters,
+                                                 num_glyphs, script));
+  EXPECT_EQ(0u, start_index);
+  EXPECT_EQ(6u, num_characters);
+  ASSERT_TRUE(TestInfo(second)->RunInfoForTesting(
+      0, start_index, num_characters, num_glyphs, script));
+  EXPECT_EQ(6u, start_index);
+  EXPECT_EQ(5u, num_characters);
+  ASSERT_TRUE(TestInfo(third)->RunInfoForTesting(0, start_index, num_characters,
+                                                 num_glyphs, script));
+  EXPECT_EQ(11u, start_index);
+  EXPECT_EQ(1u, num_characters);
+
   HarfBuzzShaper shaper2(string.Characters16(), 6);
   RefPtr<ShapeResult> first_reference = shaper2.Shape(&font, direction);
 
   HarfBuzzShaper shaper3(string.Characters16() + 6, 5);
   RefPtr<ShapeResult> second_reference = shaper3.Shape(&font, direction);
 
   HarfBuzzShaper shaper4(string.Characters16() + 11, 1);
   RefPtr<ShapeResult> third_reference = shaper4.Shape(&font, direction);
 
   // Width of each segment should be the same when shaped using start and end
@@ skipping 166 matching lines @@
             composite_result->SnappedStartPositionForOffset(5));
   EXPECT_EQ(result->SnappedStartPositionForOffset(6),
             composite_result->SnappedStartPositionForOffset(6));
   EXPECT_EQ(result->SnappedStartPositionForOffset(7),
             composite_result->SnappedStartPositionForOffset(7));
   EXPECT_EQ(result->SnappedStartPositionForOffset(8),
             composite_result->SnappedStartPositionForOffset(8));
 }
 
 }  // namespace blink