From 74138b9febd37eac0fc26b8efb110014a83a52c6 Mon Sep 17 00:00:00 2001
From: Jeremy Roman <jbroman@chromium.org>
Date: Wed, 07 Aug 2019 13:26:48 +0000
Subject: [PATCH] WTF: Make LinkedHashSet understand values for which memset initialization would be bad.
Includes a unit test which fails before, and uses this to fix FontCacheKeyTraits.
Bug: 980025
Change-Id: If41f97444c7fd37b9b95d6dadaf3da5689079e9e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1739948
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Commit-Queue: Jeremy Roman <jbroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#684731}
---
diff --git a/third_party/blink/renderer/platform/fonts/font_cache_key.h b/third_party/blink/renderer/platform/fonts/font_cache_key.h
index 0efc8fb..90063cb 100644
--- a/third_party/blink/renderer/platform/fonts/font_cache_key.h
+++ b/third_party/blink/renderer/platform/fonts/font_cache_key.h
@@ -133,6 +133,10 @@
struct FontCacheKeyTraits : WTF::SimpleClassHashTraits<FontCacheKey> {
STATIC_ONLY(FontCacheKeyTraits);
+
+ // std::string's empty state need not be zero in all implementations,
+ // and it is held within FontFaceCreationParams.
+ static const bool kEmptyValueIsZero = false;
};
} // namespace blink
diff --git a/third_party/blink/renderer/platform/wtf/linked_hash_set.h b/third_party/blink/renderer/platform/wtf/linked_hash_set.h
index b35b6e9..77e524c 100644
--- a/third_party/blink/renderer/platform/wtf/linked_hash_set.h
+++ b/third_party/blink/renderer/platform/wtf/linked_hash_set.h
@@ -146,6 +146,11 @@
LinkedHashSetNodeBase* next)
: LinkedHashSetNodeBase(prev, next), value_(value) {}
+ LinkedHashSetNode(ValueArg&& value,
+ LinkedHashSetNodeBase* prev,
+ LinkedHashSetNodeBase* next)
+ : LinkedHashSetNodeBase(prev, next), value_(std::move(value)) {}
+
LinkedHashSetNode(LinkedHashSetNode&& other)
: LinkedHashSetNodeBase(std::move(other)),
value_(std::move(other.value_)) {}
@@ -445,10 +450,13 @@
// The slot is empty when the next_ field is zero so it's safe to zero
// the backing.
- static const bool kEmptyValueIsZero = true;
+ static const bool kEmptyValueIsZero = ValueTraits::kEmptyValueIsZero;
static const bool kHasIsEmptyValueFunction = true;
static bool IsEmptyValue(const Node& node) { return !node.next_; }
+ static Node EmptyValue() {
+ return Node(ValueTraits::EmptyValue(), nullptr, nullptr);
+ }
static const int kDeletedValue = -1;
diff --git a/third_party/blink/renderer/platform/wtf/list_hash_set_test.cc b/third_party/blink/renderer/platform/wtf/list_hash_set_test.cc
index 4c3f899..cd1be00 100644
--- a/third_party/blink/renderer/platform/wtf/list_hash_set_test.cc
+++ b/third_party/blink/renderer/platform/wtf/list_hash_set_test.cc
@@ -487,6 +487,7 @@
};
struct Complicated {
+ Complicated() : Complicated(0) {}
Complicated(int value) : simple_(value) { objects_constructed_++; }
Complicated(const Complicated& other) : simple_(other.simple_) {
@@ -495,9 +496,6 @@
Simple simple_;
static int objects_constructed_;
-
- private:
- Complicated() = delete;
};
int Complicated::objects_constructed_ = 0;
@@ -731,4 +729,45 @@
} // anonymous namespace
+// A unit type which objects to its state being initialized wrong.
+struct InvalidZeroValue {
+ InvalidZeroValue() = default;
+ InvalidZeroValue(WTF::HashTableDeletedValueType) : deleted_(true) {}
+ ~InvalidZeroValue() { CHECK(ok_); }
+ bool IsHashTableDeletedValue() const { return deleted_; }
+
+ bool ok_ = true;
+ bool deleted_ = false;
+};
+
+template <>
+struct HashTraits<InvalidZeroValue> : SimpleClassHashTraits<InvalidZeroValue> {
+ static const bool kEmptyValueIsZero = false;
+};
+
+template <>
+struct DefaultHash<InvalidZeroValue> {
+ struct Hash {
+ static unsigned GetHash(const InvalidZeroValue&) { return 0; }
+ static bool Equal(const InvalidZeroValue&, const InvalidZeroValue&) {
+ return true;
+ }
+ };
+};
+
+template <typename Set>
+class ListOrLinkedHashSetInvalidZeroTest : public testing::Test {};
+
+using InvalidZeroValueSetTypes =
+ testing::Types<ListHashSet<InvalidZeroValue>,
+ ListHashSet<InvalidZeroValue, 1>,
+ LinkedHashSet<InvalidZeroValue>>;
+TYPED_TEST_SUITE(ListOrLinkedHashSetInvalidZeroTest, InvalidZeroValueSetTypes);
+
+TYPED_TEST(ListOrLinkedHashSetInvalidZeroTest, InvalidZeroValue) {
+ using Set = TypeParam;
+ Set set;
+ set.insert(InvalidZeroValue());
+}
+
} // namespace WTF
