实现接口

db/db_impl.cc

@@ -1198,6 +1198,10 @@ Status DBImpl::Put(const WriteOptions& o, const Slice& key, const Slice& val) {
   return DB::Put(o, key, val);
 }
 
+Status DBImpl::Put(const WriteOptions& o, const Slice& key, const Slice& val, uint64_t ttl) {
+  return DB::Put(o, key, val, ttl);
+} // 实现新的put接口，心
+
 Status DBImpl::Delete(const WriteOptions& options, const Slice& key) {
   return DB::Delete(options, key);
 }
@@ -1491,6 +1495,13 @@ Status DB::Put(const WriteOptions& opt, const Slice& key, const Slice& value) {
   return Write(opt, &batch);
 }
 
+// 假设增加一个新的Put接口，包含TTL参数, 单位（秒）
+Status DB::Put(const WriteOptions& opt, const Slice& key, const Slice& value, uint64_t ttl){
+  WriteBatch batch;
+  batch.Put(key, value, ttl);
+  return Write(opt, &batch);
+} // 这里应该是新的PUT接口的真正实现的地方，还是由本来的DB类实现，怪？心
+
 Status DB::Delete(const WriteOptions& opt, const Slice& key) {
   WriteBatch batch;
   batch.Delete(key);

db/db_impl.h

@@ -38,6 +38,8 @@ class DBImpl : public DB {
   // Implementations of the DB interface
   Status Put(const WriteOptions&, const Slice& key,
              const Slice& value) override;
+  Status Put(const WriteOptions&, const Slice& key,
+             const Slice& value, uint64_t ttl) override;  //实现新的put接口，心   
   Status Delete(const WriteOptions&, const Slice& key) override;
   Status Write(const WriteOptions& options, WriteBatch* updates) override;
   Status Get(const ReadOptions& options, const Slice& key,

db/db_test.cc

@@ -2117,6 +2117,10 @@ class ModelDB : public DB {
   Status Put(const WriteOptions& o, const Slice& k, const Slice& v) override {
     return DB::Put(o, k, v);
   }
+  Status Put(const WriteOptions& o, const Slice& k,
+                     const Slice& v, uint64_t ttl) override {
+    return DB::Put(o, k, v);
+  }// 实现的是DB里的新put接口，心
   Status Delete(const WriteOptions& o, const Slice& key) override {
     return DB::Delete(o, key);
   }

db/write_batch.cc

@@ -21,6 +21,8 @@
 #include "leveldb/db.h"
 #include "util/coding.h"
 
+#include <sstream>  // For std::ostringstream 心
+#include <cstdint>  // 引入uint64_t类型,燕
 namespace leveldb {
 
 // WriteBatch header has an 8-byte sequence number followed by a 4-byte count.
@@ -102,6 +104,34 @@ void WriteBatch::Put(const Slice& key, const Slice& value) {
   PutLengthPrefixedSlice(&rep_, value);
 }
 
+void WriteBatch::Put(const Slice& key, const Slice& value, std::uint64_t ttl) {
+  WriteBatchInternal::SetCount(this, WriteBatchInternal::Count(this) + 1);
+  rep_.push_back(static_cast<char>(kTypeValue));
+  PutLengthPrefixedSlice(&rep_, key);
+
+  // 获取当前时间
+  auto now = std::chrono::system_clock::now();
+    
+  // 加上ttl
+  auto future_time = now + std::chrono::seconds(ttl);
+    
+  // 转换为 time_t
+  std::time_t future_time_t = std::chrono::system_clock::to_time_t(future_time);
+    
+  // 将 time_t 转换为 tm 结构
+  std::tm* local_tm = std::localtime(&future_time_t);
+
+  // 格式化为字符串
+  char buffer[20];  // 格式化字符串的缓冲区
+  std::strftime(buffer, sizeof(buffer), "%Y-%m-%d %H:%M:%S", local_tm);
+  std::string future_time_str(buffer);
+
+  // 拼接原本的值和时间字符串
+  std::string combined_str = value.ToString() + future_time_str;
+  PutLengthPrefixedSlice(&rep_, Slice(combined_str));
+
+} // 心
+
 void WriteBatch::Delete(const Slice& key) {
   WriteBatchInternal::SetCount(this, WriteBatchInternal::Count(this) + 1);
   rep_.push_back(static_cast<char>(kTypeDeletion));

include/leveldb/write_batch.h

@@ -22,6 +22,7 @@
 #define STORAGE_LEVELDB_INCLUDE_WRITE_BATCH_H_
 
 #include <string>
+#include <cstdint>  // 引入uint64_t类型，燕
 
 #include "leveldb/export.h"
 #include "leveldb/status.h"
@@ -50,6 +51,8 @@ class LEVELDB_EXPORT WriteBatch {
   // Store the mapping "key->value" in the database.
   void Put(const Slice& key, const Slice& value);
 
+  void Put(const Slice& key, const Slice& value, uint64_t ttl); //心
+
   // If the database contains a mapping for "key", erase it.  Else do nothing.
   void Delete(const Slice& key);
 

test/ttl_test.cc

@@ -7,7 +7,7 @@
 
 
 using namespace leveldb;
-
+// 定义了数据的大小，用于插入大数据集，燕
 constexpr int value_size = 2048;
 constexpr int data_size = 128 << 20;
 
@@ -23,7 +23,8 @@ void InsertData(DB *db, uint64_t ttl/* second */) {
   srand(static_cast<unsigned int>(time(0)));
 
   for (int i = 0; i < key_num; i++) {
-    int key_ = rand() % key_num+1;
+    //int key_ = rand() % key_num+1;
+    int key_ = i % key_num+1;
     std::string key = std::to_string(key_);
     std::string value(value_size, 'a');
     db->Put(writeOptions, key, value, ttl);
@@ -34,10 +35,11 @@ void GetData(DB *db, int size = (1 << 30)) {
   ReadOptions readOptions;
   int key_num = data_size / value_size;
   
-  // 点查
+  // 使用随机种子生成随机键进行点查（单次查询），燕
   srand(static_cast<unsigned int>(time(0)));
   for (int i = 0; i < 100; i++) {
     int key_ = rand() % key_num+1;
+    //int key_ = i % key_num+1;
     std::string key = std::to_string(key_);
     std::string value;
     db->Get(readOptions, key, &value);
@@ -60,17 +62,19 @@ TEST(TestTTL, ReadTTL) {
     int key_num = data_size / value_size;
     srand(static_cast<unsigned int>(time(0)));
     for (int i = 0; i < 100; i++) {
-        int key_ = rand() % key_num+1;
+        //int key_ = rand() % key_num+1;
+        int key_ = i % key_num+1;
         std::string key = std::to_string(key_);
         std::string value;
         status = db->Get(readOptions, key, &value);
         ASSERT_TRUE(status.ok());
     }
-
+    // 等待TTL过期，使插入的数据变为“过期”状态，燕
     Env::Default()->SleepForMicroseconds(ttl * 1000000);
 
     for (int i = 0; i < 100; i++) {
         int key_ = rand() % key_num+1;
+        // int key_ = i % key_num+1;
         std::string key = std::to_string(key_);
         std::string value;
         status = db->Get(readOptions, key, &value);
@@ -99,9 +103,10 @@ TEST(TestTTL, CompactionTTL) {
 
     db->CompactRange(nullptr, nullptr);
 
-    leveldb::Range ranges[1];
+    // leveldb::Range ranges[1]; // 这里为什么要重复定义？心
     ranges[0] = leveldb::Range("-", "A");
-    uint64_t sizes[1];
+    // uint64_t sizes[1]; // 心
+
     db->GetApproximateSizes(ranges, 1, sizes);
     ASSERT_EQ(sizes[0], 0);
 }