fix tryAtomicRename() with src == dst bug

Core/MMKV.h

@@ -226,7 +226,7 @@ class MMKV {
     void notifyContentChanged();
 
 #if defined(MMKV_ANDROID) && !defined(MMKV_DISABLE_CRYPT)
-    void checkReSetCryptKey(int fd, int metaFD, std::string *cryptKey);
+    void checkReSetCryptKey(int fd, int metaFD, const std::string *cryptKey);
 #endif
     static bool backupOneToDirectory(const std::string &mmapKey, const MMKVPath_t &dstPath, const MMKVPath_t &srcPath, bool compareFullPath);
     static size_t backupAllToDirectory(const MMKVPath_t &dstDir, const MMKVPath_t &srcDir, bool isInSpecialDir);
@@ -591,5 +591,5 @@ bool MMKV::getVector(MMKVKey_t key, T &result) {
 
 MMKV_NAMESPACE_END
 
-#endif
+#endif // __cplusplus
 #endif // MMKV_MMKV_H

Core/MMKV_Android.cpp

@@ -39,11 +39,11 @@ using namespace mmkv;
 extern unordered_map<string, MMKV *> *g_instanceDic;
 extern ThreadLock *g_instanceLock;
 
-MMKV::MMKV(const string &mmapID, int size, MMKVMode mode, string *cryptKey, string *rootPath, size_t expectedCapacity)
+MMKV::MMKV(const string &mmapID, int size, MMKVMode mode, const string *cryptKey, const string *rootPath, size_t expectedCapacity)
     : m_mmapID((mode & MMKV_BACKUP) ? mmapID : mmapedKVKey(mmapID, rootPath)) // historically Android mistakenly use mmapKey as mmapID
     , m_mode(mode)
     , m_path(mappedKVPathWithID(m_mmapID, mode, rootPath))
-    , m_crcPath(crcPathWithID(m_mmapID, mode, rootPath))
+    , m_crcPath(crcPathWithPath(m_path))
     , m_dic(nullptr)
     , m_dicCrypt(nullptr)
     , m_expectedCapacity(std::max<size_t>(DEFAULT_MMAP_SIZE, roundUp<size_t>(expectedCapacity, DEFAULT_MMAP_SIZE)))
@@ -88,11 +88,11 @@ MMKV::MMKV(const string &mmapID, int size, MMKVMode mode, string *cryptKey, stri
     }*/
 }
 
-MMKV::MMKV(const string &mmapID, int ashmemFD, int ashmemMetaFD, string *cryptKey)
+MMKV::MMKV(const string &mmapID, int ashmemFD, int ashmemMetaFD, const string *cryptKey)
     : m_mmapID(mmapID)
     , m_mode(MMKV_ASHMEM)
     , m_path(mappedKVPathWithID(m_mmapID, MMKV_ASHMEM, nullptr))
-    , m_crcPath(crcPathWithID(m_mmapID, MMKV_ASHMEM, nullptr))
+    , m_crcPath(crcPathWithPath(m_path))
     , m_dic(nullptr)
     , m_dicCrypt(nullptr)
     , m_file(new MemoryFile(ashmemFD))
@@ -137,7 +137,7 @@ MMKV::MMKV(const string &mmapID, int ashmemFD, int ashmemMetaFD, string *cryptKe
     }*/
 }
 
-MMKV *MMKV::mmkvWithID(const string &mmapID, int size, MMKVMode mode, string *cryptKey, string *rootPath, size_t expectedCapacity) {
+MMKV *MMKV::mmkvWithID(const string &mmapID, int size, MMKVMode mode, const string *cryptKey, const string *rootPath, size_t expectedCapacity) {
     if (mmapID.empty() || !g_instanceLock) {
         return nullptr;
     }
@@ -162,7 +162,7 @@ MMKV *MMKV::mmkvWithID(const string &mmapID, int size, MMKVMode mode, string *cr
     return kv;
 }
 
-MMKV *MMKV::mmkvWithAshmemFD(const string &mmapID, int fd, int metaFD, string *cryptKey) {
+MMKV *MMKV::mmkvWithAshmemFD(const string &mmapID, int fd, int metaFD, const string *cryptKey) {
 
     if (fd < 0 || !g_instanceLock) {
         return nullptr;
@@ -191,7 +191,7 @@ int MMKV::ashmemMetaFD() {
 }
 
 #    ifndef MMKV_DISABLE_CRYPT
-void MMKV::checkReSetCryptKey(int fd, int metaFD, string *cryptKey) {
+void MMKV::checkReSetCryptKey(int fd, int metaFD, const string *cryptKey) {
     SCOPED_LOCK(m_lock);
 
     checkReSetCryptKey(cryptKey);

Core/MemoryFile_Linux.cpp

@@ -72,6 +72,10 @@ bool tryAtomicRename(const MMKVPath_t &srcPath, const MMKVPath_t &dstPath) {
         MMKVWarning("fail on syscall(SYS_renameat2) [%s] to [%s], %d(%s)", srcPath.c_str(), dstPath.c_str(), errno,
                     strerror(errno));
     }
+
+    if (renamed && (srcPath != dstPath)) {
+        ::unlink(srcPath.c_str());
+    }
 #endif // SYS_renameat2 && !MMKV_OHOS
 
     if (!renamed) {
@@ -81,7 +85,6 @@ bool tryAtomicRename(const MMKVPath_t &srcPath, const MMKVPath_t &dstPath) {
         }
     }
 
-    ::unlink(srcPath.c_str());
     return true;
 }
 

Core/MemoryFile_OSX.cpp

@@ -58,6 +58,9 @@ void tryResetFileProtection(const string &path) {
 namespace mmkv {
 
 bool tryAtomicRename(const char *src, const char *dst) {
+    if (!src || !dst) {
+        return false;
+    }
     bool renamed = false;
 
     // try atomic swap first
@@ -65,6 +68,9 @@ bool tryAtomicRename(const char *src, const char *dst) {
         // renameat2() equivalent
         if (renamex_np(src, dst, RENAME_SWAP) == 0) {
             renamed = true;
+            if (strcmp(src, dst) != 0) {
+                ::unlink(src);
+            }
         } else if (errno != ENOENT) {
             MMKVError("fail to renamex_np %s to %s, %s", src, dst, strerror(errno));
         }
@@ -78,8 +84,6 @@ bool tryAtomicRename(const char *src, const char *dst) {
         }
     }
 
-    ::unlink(src);
-
     return true;
 }