remove filesystem and fix bug for version_3

CMakeLists.txt

@@ -10,7 +10,7 @@ project(leveldb VERSION 1.23.0 LANGUAGES C CXX)
 if(NOT CMAKE_C_STANDARD)
   # This project can use C11, but will gracefully decay down to C89.
   # 我改到17了
-  set(CMAKE_C_STANDARD 17)
+  set(CMAKE_C_STANDARD 11)
   set(CMAKE_C_STANDARD_REQUIRED OFF)
   set(CMAKE_C_EXTENSIONS OFF)
 endif(NOT CMAKE_C_STANDARD)
@@ -18,7 +18,7 @@ endif(NOT CMAKE_C_STANDARD)
 # C++ standard can be overridden when this is used as a sub-project.
 if(NOT CMAKE_CXX_STANDARD)
   # This project requires C++17.
-  set(CMAKE_CXX_STANDARD 17)
+  set(CMAKE_CXX_STANDARD 11)
   set(CMAKE_CXX_STANDARD_REQUIRED ON)
   set(CMAKE_CXX_EXTENSIONS OFF)
 endif(NOT CMAKE_CXX_STANDARD)

benchmarks/db_bench.cc

@@ -74,7 +74,7 @@ static int FLAGS_reads = -1;
 static int FLAGS_threads = 1;
 
 // Size of each value
-static int FLAGS_value_size = 1000;
+static int FLAGS_value_size = 5000;
 
 // Arrange to generate values that shrink to this fraction of
 // their original size after compression

db/db_impl.cc

@@ -18,7 +18,6 @@
 #include <atomic>
 #include <cstdint>
 #include <cstdio>
-#include <filesystem>
 #include <fstream>
 #include <iostream>
 #include <set>
@@ -39,7 +38,6 @@
 #include "util/coding.h"
 #include "util/logging.h"
 #include "util/mutexlock.h"
-namespace fs = std::filesystem;
 
 namespace leveldb {
 
@@ -1740,21 +1738,16 @@ void DBImpl::GarbageCollect() {
   gc_mutex_.AssertHeld();
   // 遍历数据库目录，找到所有 valuelog 文件
   Log(options_.info_log, "start gc ");
-  auto files_set = fs::directory_iterator(dbname_);
+  std::vector<std::string> filenames;
+  Status s = env_->GetChildren(dbname_, &filenames);
+  assert(s.ok());
   std::set<std::string> valuelog_set;
-  // std::string cur_valuelog_name =
-  //     ValueLogFileName(dbname_, valuelogfile_number_);
-  for (const auto& cur_log_file : files_set) {
-    if (fs::exists(cur_log_file) &&
-        fs::is_regular_file(fs::status(cur_log_file)) &&
-        IsValueLogFile(cur_log_file.path().filename().string())) {
-      // if (cur_valuelog_name == cur_log_file.path().filename().string())
-      //   continue;
-      valuelog_set.emplace(cur_log_file.path().filename().string());
+  for (const auto& filename:filenames) {
+    if (IsValueLogFile(filename)) {
+      valuelog_set.emplace(filename);
     }
   }
   for (std::string valuelog_name : valuelog_set) {
-    // std::cout << valuelog_name << std::endl;
     uint64_t cur_log_number = GetValueLogID(valuelog_name);
     valuelog_name = ValueLogFileName(dbname_, cur_log_number);
     if (cur_log_number == valuelogfile_number_) {
@@ -1887,6 +1880,10 @@ void DBImpl::GarbageCollect() {
         // Key 不存在，忽略此记录
         continue;
       }
+      else if(stored_value.data()[0]==(char)(0x00)){
+        //value is too small
+        continue;
+      }
 
       if (!status.ok()) {
         std::cerr << "Error accessing sstable: " << status.ToString()
@@ -1923,7 +1920,9 @@ void DBImpl::GarbageCollect() {
     // 清理旧文件（如果需要）
     cur_valuelog.close();
 
-    fs::remove(valuelog_name.c_str());  // 删除旧的 ValueLog 文件
+    env_->RemoveFile(valuelog_name);
+
+
     Log(options_.info_log, "remove file during gc %s", valuelog_name.c_str());
   }
 }

util/coding.cc

@@ -3,8 +3,7 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
 
 #include "util/coding.h"
-#include <filesystem>
-
+#include <sstream>
 
 
 namespace leveldb {
@@ -174,27 +173,38 @@ void ParseStoredValue(const std::string& stored_value, uint64_t& valuelog_id,
 }
 
 // 示例：获取 ValueLog 文件 ID
+// 示例：获取 ValueLog 文件 ID
 uint64_t GetValueLogID(const std::string& valuelog_name) {
-  // 使用 std::filesystem::path 解析文件名
-  std::filesystem::path file_path(valuelog_name);
-  std::string filename = file_path.filename().string();  // 获取文件名部分
-
-  // 查找文件名中的 '.' 位置，提取数字部分
-  auto pos = filename.find('.');
-  if (pos == std::string::npos) {
-    assert(0);
-  }
 
-  // 提取数字部分
-  std::string id_str = filename.substr(0, pos);
-  // 检查提取的部分是否为有效数字
-  for (char c : id_str) {
-    if (!isdigit(c)) {
-      assert(0);
+    // 获取文件名部分（假设文件名格式为 "number.extension"）
+    size_t pos = valuelog_name.find_last_of('/');
+    std::string filename;
+    if (pos != std::string::npos) {
+        filename = valuelog_name.substr(pos + 1);
+    } else {
+        filename = valuelog_name;
+    }
+
+    // 查找文件名中的 '.' 位置，提取数字部分
+    pos = filename.find('.');
+    assert(pos != std::string::npos);
+
+    // 提取数字部分
+    std::string id_str = filename.substr(0, pos);
+
+    // 检查文件扩展名是否为 .valuelog
+    if (filename.substr(pos + 1) != "valuelog") {
+        assert(0);
+    }
+
+    // 转换为 uint64_t
+    uint64_t id;
+    std::istringstream iss(id_str);
+    if (!(iss >> id)) {
+        assert(0);
     }
-  }
 
-  return std::stoull(id_str);  // 转换为 uint64_t
+    return id;
 }
 
 // Helper function to split the set of files into chunks