Update hash function

acvictor · Apr 29, 2024 · f2d65d7 · f2d65d7
1 parent 59c21b6
commit f2d65d7
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Showing 2 changed files with 17 additions and 25 deletions.
diff --git a/velox/connectors/hive/FileHandleKey.h b/velox/connectors/hive/FileHandleKey.h
@@ -58,23 +58,19 @@ class FileHandleKey {
 };
 } // namespace facebook::velox
 
-template <class T>
-inline void hash_combine(std::size_t& seed, const T& v) {
-  std::hash<T> hasher;
-  // See boost::hash_combine
-  // https://www.boost.org/doc/libs/1_55_0/doc/html/hash/reference.html#boost.hash_combine
-  seed ^= hasher(v) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
-}
-
 namespace std {
 template <>
 struct hash<facebook::velox::FileHandleKey> {
   size_t operator()(const facebook::velox::FileHandleKey& key) const {
-    size_t seed = 0;
-    hash_combine(seed, key.getFilePath());
-    hash_combine(seed, key.getFileSize());
-    hash_combine(seed, key.getModificationTime());
-    return seed;
+    auto hasher = folly::Hash{};
+    uint64_t combinedHash = 0;
+    combinedHash = folly::hash::commutative_hash_combine_value_generic(
+        combinedHash, hasher, key.getFileSize());
+    combinedHash = folly::hash::commutative_hash_combine_value_generic(
+        combinedHash, hasher, key.getModificationTime());
+    combinedHash = folly::hash::commutative_hash_combine_value_generic(
+        combinedHash, hasher, key.getFilePath());
+    return combinedHash;
   }
 };
 } // namespace std
diff --git a/velox/connectors/hive/tests/FileHandleTest.cpp b/velox/connectors/hive/tests/FileHandleTest.cpp
@@ -83,12 +83,6 @@ TEST(FileHandleTest, retrieveCachedLocalFile) {
 
   auto tempFile = exec::test::TempFilePath::create();
   const auto& filename = tempFile->getPath();
-  remove(filename.c_str());
-
-  {
-    LocalWriteFile writeFile(filename);
-    writeFile.append("foo");
-  }
 
   FileHandleFactory factory(
       std::make_unique<
@@ -104,14 +98,16 @@ TEST(FileHandleTest, retrieveCachedLocalFile) {
 
   factory.retrieveCached(
       {FileHandleKey(
-           tempFile->fileSize(), tempFile->fileModifiedTime(), filename),
-       FileHandleKey(
-           tempFile->fileSize() + 1,
-           tempFile->fileModifiedTime() + 1,
-           filename)},
+          tempFile->fileSize(), tempFile->fileModifiedTime(), filename)},
       &cached,
       &missing);
-
   ASSERT_EQ(1, cached.size());
+  ASSERT_EQ(0, missing.size());
+
+  factory.retrieveCached(
+      {FileHandleKey(
+          tempFile->fileSize() + 1, tempFile->fileModifiedTime(), filename)},
+      &cached,
+      &missing);
   ASSERT_EQ(1, missing.size());
 }