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// Copyright 2016 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 "core/css/CSSStyleSheet.h"
#include "core/css/StyleRule.h"
#include "core/css/StyleSheetContents.h"
#include "core/css/parser/CSSLazyParsingState.h"
#include "core/css/parser/CSSParser.h"
#include "core/css/parser/CSSParserContext.h"
#include "core/frame/FrameHost.h"
#include "core/testing/DummyPageHolder.h"
#include "platform/heap/Heap.h"
#include "platform/testing/HistogramTester.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "wtf/text/WTFString.h"
namespace blink {
class CSSLazyParsingTest : public testing::Test {
public:
bool hasParsedProperties(StyleRule* rule) {
return rule->hasParsedProperties();
}
StyleRule* ruleAt(StyleSheetContents* sheet, size_t index) {
return toStyleRule(sheet->childRules()[index]);
}
protected:
HistogramTester m_histogramTester;
Persistent<StyleSheetContents> m_cachedContents;
};
TEST_F(CSSLazyParsingTest, Simple) {
CSSParserContext* context = CSSParserContext::create(HTMLStandardMode);
StyleSheetContents* styleSheet = StyleSheetContents::create(context);
String sheetText = "body { background-color: red; }";
CSSParser::parseSheet(context, styleSheet, sheetText, true /* lazy parse */);
StyleRule* rule = ruleAt(styleSheet, 0);
EXPECT_FALSE(hasParsedProperties(rule));
rule->properties();
EXPECT_TRUE(hasParsedProperties(rule));
}
// Avoiding lazy parsing for trivially empty blocks helps us perform the
// shouldConsiderForMatchingRules optimization.
TEST_F(CSSLazyParsingTest, DontLazyParseEmpty) {
CSSParserContext* context = CSSParserContext::create(HTMLStandardMode);
StyleSheetContents* styleSheet = StyleSheetContents::create(context);
String sheetText = "body { }";
CSSParser::parseSheet(context, styleSheet, sheetText, true /* lazy parse */);
StyleRule* rule = ruleAt(styleSheet, 0);
EXPECT_TRUE(hasParsedProperties(rule));
EXPECT_FALSE(
rule->shouldConsiderForMatchingRules(false /* includeEmptyRules */));
}
// Avoid parsing rules with ::before or ::after to avoid causing
// collectFeatures() when we trigger parsing for attr();
TEST_F(CSSLazyParsingTest, DontLazyParseBeforeAfter) {
CSSParserContext* context = CSSParserContext::create(HTMLStandardMode);
StyleSheetContents* styleSheet = StyleSheetContents::create(context);
String sheetText =
"p::before { content: 'foo' } p .class::after { content: 'bar' } ";
CSSParser::parseSheet(context, styleSheet, sheetText, true /* lazy parse */);
EXPECT_TRUE(hasParsedProperties(ruleAt(styleSheet, 0)));
EXPECT_TRUE(hasParsedProperties(ruleAt(styleSheet, 1)));
}
// Test for crbug.com/664115 where |shouldConsiderForMatchingRules| would flip
// from returning false to true if the lazy property was parsed. This is a
// dangerous API because callers will expect the set of matching rules to be
// identical if the stylesheet is not mutated.
TEST_F(CSSLazyParsingTest, ShouldConsiderForMatchingRulesDoesntChange1) {
CSSParserContext* context = CSSParserContext::create(HTMLStandardMode);
StyleSheetContents* styleSheet = StyleSheetContents::create(context);
String sheetText = "p::first-letter { ,badness, } ";
CSSParser::parseSheet(context, styleSheet, sheetText, true /* lazy parse */);
StyleRule* rule = ruleAt(styleSheet, 0);
EXPECT_FALSE(hasParsedProperties(rule));
EXPECT_TRUE(
rule->shouldConsiderForMatchingRules(false /* includeEmptyRules */));
// Parse the rule.
rule->properties();
// Now, we should still consider this for matching rules even if it is empty.
EXPECT_TRUE(hasParsedProperties(rule));
EXPECT_TRUE(
rule->shouldConsiderForMatchingRules(false /* includeEmptyRules */));
}
// Test the same thing as above, with a property that does not get lazy parsed,
// to ensure that we perform the optimization where possible.
TEST_F(CSSLazyParsingTest, ShouldConsiderForMatchingRulesSimple) {
CSSParserContext* context = CSSParserContext::create(HTMLStandardMode);
StyleSheetContents* styleSheet = StyleSheetContents::create(context);
String sheetText = "p::before { ,badness, } ";
CSSParser::parseSheet(context, styleSheet, sheetText, true /* lazy parse */);
StyleRule* rule = ruleAt(styleSheet, 0);
EXPECT_TRUE(hasParsedProperties(rule));
EXPECT_FALSE(
rule->shouldConsiderForMatchingRules(false /* includeEmptyRules */));
}
// Regression test for crbug.com/660290 where we change the underlying owning
// document from the StyleSheetContents without changing the UseCounter. This
// test ensures that the new UseCounter is used when doing new parsing work.
TEST_F(CSSLazyParsingTest, ChangeDocuments) {
std::unique_ptr<DummyPageHolder> dummyHolder =
DummyPageHolder::create(IntSize(500, 500));
CSSParserContext* context = CSSParserContext::create(
HTMLStandardMode, CSSParserContext::DynamicProfile,
UseCounter::getFrom(&dummyHolder->document()));
m_cachedContents = StyleSheetContents::create(context);
{
CSSStyleSheet* sheet =
CSSStyleSheet::create(m_cachedContents, dummyHolder->document());
DCHECK(sheet);
String sheetText = "body { background-color: red; } p { color: orange; }";
CSSParser::parseSheet(context, m_cachedContents, sheetText,
true /* lazy parse */);
// Parse the first property set with the first document as owner.
StyleRule* rule = ruleAt(m_cachedContents, 0);
EXPECT_FALSE(hasParsedProperties(rule));
rule->properties();
EXPECT_TRUE(hasParsedProperties(rule));
EXPECT_EQ(&dummyHolder->document(),
m_cachedContents->singleOwnerDocument());
UseCounter& useCounter1 = dummyHolder->document().frameHost()->useCounter();
EXPECT_TRUE(useCounter1.isCounted(CSSPropertyBackgroundColor));
EXPECT_FALSE(useCounter1.isCounted(CSSPropertyColor));
// Change owner document.
m_cachedContents->unregisterClient(sheet);
dummyHolder.reset();
}
// Ensure no stack references to oilpan objects.
ThreadState::current()->collectAllGarbage();
std::unique_ptr<DummyPageHolder> dummyHolder2 =
DummyPageHolder::create(IntSize(500, 500));
CSSStyleSheet* sheet2 =
CSSStyleSheet::create(m_cachedContents, dummyHolder2->document());
EXPECT_EQ(&dummyHolder2->document(), m_cachedContents->singleOwnerDocument());
// Parse the second property set with the second document as owner.
StyleRule* rule2 = ruleAt(m_cachedContents, 1);
EXPECT_FALSE(hasParsedProperties(rule2));
rule2->properties();
EXPECT_TRUE(hasParsedProperties(rule2));
UseCounter& useCounter2 = dummyHolder2->document().frameHost()->useCounter();
EXPECT_TRUE(sheet2);
EXPECT_TRUE(useCounter2.isCounted(CSSPropertyColor));
EXPECT_FALSE(useCounter2.isCounted(CSSPropertyBackgroundColor));
}
TEST_F(CSSLazyParsingTest, SimpleRuleUsagePercent) {
CSSParserContext* context = CSSParserContext::create(HTMLStandardMode);
StyleSheetContents* styleSheet = StyleSheetContents::create(context);
std::string metricName = "Style.LazyUsage.Percent";
m_histogramTester.expectTotalCount(metricName, 0);
String sheetText =
"body { background-color: red; }"
"p { color: blue; }"
"a { color: yellow; }"
"#id { color: blue; }"
"div { color: grey; }";
CSSParser::parseSheet(context, styleSheet, sheetText, true /* lazy parse */);
m_histogramTester.expectTotalCount(metricName, 1);
m_histogramTester.expectUniqueSample(metricName,
CSSLazyParsingState::UsageGe0, 1);
ruleAt(styleSheet, 0)->properties();
m_histogramTester.expectTotalCount(metricName, 2);
m_histogramTester.expectBucketCount(metricName,
CSSLazyParsingState::UsageGt10, 1);
ruleAt(styleSheet, 1)->properties();
m_histogramTester.expectTotalCount(metricName, 3);
m_histogramTester.expectBucketCount(metricName,
CSSLazyParsingState::UsageGt25, 1);
ruleAt(styleSheet, 2)->properties();
m_histogramTester.expectTotalCount(metricName, 4);
m_histogramTester.expectBucketCount(metricName,
CSSLazyParsingState::UsageGt50, 1);
ruleAt(styleSheet, 3)->properties();
m_histogramTester.expectTotalCount(metricName, 5);
m_histogramTester.expectBucketCount(metricName,
CSSLazyParsingState::UsageGt75, 1);
// Parsing the last rule bumps both Gt90 and All buckets.
ruleAt(styleSheet, 4)->properties();
m_histogramTester.expectTotalCount(metricName, 7);
m_histogramTester.expectBucketCount(metricName,
CSSLazyParsingState::UsageGt90, 1);
m_histogramTester.expectBucketCount(metricName, CSSLazyParsingState::UsageAll,
1);
}
} // namespace blink
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