cleanup platform specific code

2026-10-17 04:30:56 +08:00 · 2021-09-27 22:10:40 +08:00
parent 82bfae8c02
commit 674e700038
9 changed files with 169 additions and 115 deletions
@@ -0,0 +1,120 @@
+/*
+ * Tencent is pleased to support the open source community by making
+ * MMKV available.
+ *
+ * Copyright (C) 2021 THL A29 Limited, a Tencent company.
+ * All rights reserved.
+ *
+ * Licensed under the BSD 3-Clause License (the "License"); you may not use
+ * this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ *       https://opensource.org/licenses/BSD-3-Clause
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "MemoryFile.h"
+
+#if defined(MMKV_ANDROID) || defined(MMKV_LINUX)
+#    include "InterProcessLock.h"
+#    include "MMBuffer.h"
+#    include "MMKVLog.h"
+#    include "ScopedLock.hpp"
+#    include <cerrno>
+#    include <utility>
+#    include <fcntl.h>
+#    include <sys/mman.h>
+#    include <sys/stat.h>
+#    include <unistd.h>
+#    include <sys/file.h>
+#    include <dirent.h>
+#    include <cstring>
+#    include <sys/sendfile.h>
+#    include <sys/syscall.h>
+
+#ifdef MMKV_ANDROID
+#include <dlfcn.h>
+typedef int (*renameat2_t)(int old_dir_fd, const char* old_path, int new_dir_fd, const char* new_path, unsigned flags);
+#endif
+
+#ifndef RENAME_EXCHANGE
+#define RENAME_EXCHANGE (1 << 1) /* Exchange source and dest */
+#endif
+
+namespace mmkv {
+
+extern bool getFileSize(int fd, size_t &size);
+
+bool tryAtomicRename(const MMKVPath_t &srcPath, const MMKVPath_t &dstPath) {
+    bool renamed = false;
+
+    // try renameat2() first
+#ifdef SYS_renameat2
+#ifdef MMKV_ANDROID
+    static auto g_renameat2 = (renameat2_t) dlsym(RTLD_DEFAULT, "renameat2");
+    if (g_renameat2) {
+        renamed = (g_renameat2(AT_FDCWD, srcPath.c_str(), AT_FDCWD, dstPath.c_str(), RENAME_EXCHANGE) == 0);
+    }
+#endif
+    if (!renamed) {
+        renamed = (syscall(SYS_renameat2, AT_FDCWD, srcPath.c_str(), AT_FDCWD, dstPath.c_str(), RENAME_EXCHANGE) == 0);
+    }
+    if (!renamed && errno != ENOENT) {
+        MMKVError("fail on renameat2() [%s] to [%s], %d(%s)", srcPath.c_str(), dstPath.c_str(), errno, strerror(errno));
+    }
+#endif // SYS_renameat2
+
+    if (!renamed) {
+        if (::rename(srcPath.c_str(), dstPath.c_str()) != 0) {
+            MMKVError("fail to rename [%s] to [%s], %d(%s)", srcPath.c_str(), dstPath.c_str(), errno, strerror(errno));
+            return false;
+        }
+    }
+
+    ::unlink(srcPath.c_str());
+    return true;
+}
+
+// do it by sendfile()
+bool copyFileContent(const MMKVPath_t &srcPath, MMKVFileHandle_t dstFD, bool needTruncate) {
+    if (dstFD < 0) {
+        return false;
+    }
+    File srcFile(srcPath, OpenFlag::ReadOnly);
+    if (!srcFile.isFileValid()) {
+        return false;
+    }
+    auto srcFileSize = srcFile.getActualFileSize();
+
+    lseek(dstFD, 0, SEEK_SET);
+    auto writtenSize = ::sendfile(dstFD, srcFile.getFd(), nullptr, srcFileSize);
+    auto ret = (writtenSize == srcFileSize);
+    if (!ret) {
+        if (writtenSize < 0) {
+            MMKVError("fail to sendfile() %s to fd[%d], %d(%s)", srcPath.c_str(), dstFD, errno, strerror(errno));
+        } else {
+            MMKVError("sendfile() %s to fd[%d], written %lld < %zu", srcPath.c_str(), dstFD, writtenSize, srcFileSize);
+        }
+    } else if (needTruncate) {
+        size_t dstFileSize = 0;
+        getFileSize(dstFD, dstFileSize);
+        if ((dstFileSize != srcFileSize) && (::ftruncate(dstFD, static_cast<off_t>(srcFileSize)) != 0)) {
+            MMKVError("fail to truncate [%d] to size [%zu], %d(%s)", dstFD, srcFileSize, errno, strerror(errno));
+            ret = false;
+        }
+    }
+
+    if (ret) {
+        MMKVInfo("copy content from %s to fd[%d] finish", srcPath.c_str(), dstFD);
+    }
+    return ret;
+}
+
+} // namespace mmkv
+
+#endif // defined(MMKV_ANDROID) || defined(MMKV_LINUX)