Reland of remove uses of folly::hash::fnv32_buf (#40233)

Summary:
Pull Request resolved: #40233

changelog: [internal]

This is a reland of D49355595 and D49358327.

the problem was using two different hashing functions in place where they must be the same.

Reviewed By: javache

Differential Revision: D50020135

fbshipit-source-id: 1cec6bc385077d371b024a0fb5d9c64ba1f6269c

packages/react-native/Libraries/WebPerformance/PerformanceEntryReporter.cpp

@@ -10,6 +10,7 @@
 #include <react/renderer/core/EventLogger.h>
 #include "NativePerformanceObserver.h"
 
+#include <functional>
 #include <unordered_map>
 
 namespace facebook::react {
@@ -298,8 +299,7 @@ void PerformanceEntryReporter::scheduleFlushBuffer() {
 
 struct StrKey {
   uint32_t key;
-  StrKey(std::string_view s)
-      : key(folly::hash::fnv32_buf(s.data(), s.length())) {}
+  StrKey(std::string_view s) : key(std::hash<std::string_view>{}(s)) {}
 
   bool operator==(const StrKey& rhs) const {
     return key == rhs.key;

packages/react-native/ReactCommon/react/renderer/core/PropsMacros.h

@@ -8,6 +8,8 @@
 #pragma once
 
 #include <react/renderer/core/RawPropsPrimitives.h>
+#include <react/utils/fnv1a.h>
+#include <functional>
 
 // We need to use clang pragmas inside of a macro below,
 // so we need to pull out the "if" statement here.
@@ -22,11 +24,11 @@
   ([]() constexpr->RawPropsPropNameHash {                 \
     CLANG_PRAGMA("clang diagnostic push")                 \
     CLANG_PRAGMA("clang diagnostic ignored \"-Wshadow\"") \
-    return folly::hash::fnv32_buf(s, sizeof(s) - 1);      \
+    return RAW_PROPS_KEY_HASH(s);                         \
     CLANG_PRAGMA("clang diagnostic pop")                  \
   }())
 
-#define RAW_PROPS_KEY_HASH(s) folly::hash::fnv32_buf(s, std::strlen(s))
+#define RAW_PROPS_KEY_HASH(s) facebook::react::fnv1a(s)
 
 // Convenience for building setProps switch statements.
 // This injects `fromRawValue` into source; each file that uses

packages/react-native/ReactCommon/react/renderer/core/RawPropsParser.cpp

@@ -198,7 +198,7 @@ void RawPropsParser::iterateOverValues(
 
         auto name = nameValue.utf8(runtime);
 
-        auto nameHash = RAW_PROPS_KEY_HASH(name.c_str());
+        auto nameHash = RAW_PROPS_KEY_HASH(name);
         auto rawValue = RawValue(jsi::dynamicFromValue(runtime, value));
 
         visit(nameHash, name.c_str(), rawValue);
@@ -213,7 +213,7 @@ void RawPropsParser::iterateOverValues(
       for (const auto& pair : dynamic.items()) {
         auto name = pair.first.getString();
 
-        auto nameHash = RAW_PROPS_KEY_HASH(name.c_str());
+        auto nameHash = RAW_PROPS_KEY_HASH(name);
         auto rawValue = RawValue{pair.second};
         visit(nameHash, name.c_str(), rawValue);
       }

packages/react-native/ReactCommon/react/utils/fnv1a.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+namespace facebook::react {
+
+/**
+ * FNV-1a hash function implementation.
+ * Implemented as described in http://www.isthe.com/chongo/tech/comp/fnv/.
+ *
+ * Please use std::hash if possible. `fnv1a` should only be used in cases
+ * when std::hash does not provide the needed functionality. For example,
+ * constexpr.
+ */
+constexpr uint32_t fnv1a(std::string_view string) noexcept {
+  constexpr uint32_t offset_basis = 2166136261;
+
+  uint32_t hash = offset_basis;
+
+  for (auto const& c : string) {
+    hash ^= static_cast<int8_t>(c);
+    // Using shifts and adds instead of multiplication with a prime number.
+    // This is faster when compiled with optimizations.
+    hash +=
+        (hash << 1) + (hash << 4) + (hash << 7) + (hash << 8) + (hash << 24);
+  }
+
+  return hash;
+}
+
+} // namespace facebook::react

packages/react-native/ReactCommon/react/utils/tests/fnv1aTests.cpp

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <gtest/gtest.h>
+#include <react/utils/fnv1a.h>
+
+namespace facebook::react {
+
+TEST(fnv1aTests, testBasicHashing) {
+  EXPECT_EQ(fnv1a("react"), fnv1a("react"));
+
+  EXPECT_NE(fnv1a("react"), fnv1a("tceat"));
+
+  auto string1 = "case 1";
+  auto string2 = "different string";
+  EXPECT_EQ(fnv1a(string1), fnv1a(string1));
+  EXPECT_NE(fnv1a(string1), fnv1a(string2));
+}
+
+} // namespace facebook::react