modify test3.cc

db/db_impl.cc

@@ -11,6 +11,10 @@
 #include <set>
 #include <string>
 #include <vector>
+#include <iomanip>
+#include <iostream>
+#include <numeric>
+#include <sstream>
 
 #include "db/builder.h"
 #include "db/db_iter.h"
@@ -1184,6 +1188,7 @@ Status DBImpl::Get(const ReadOptions& options, const Slice& key,
   slot_page_->get_slot(slot_num, &sc);
   vlog_set_->get_value(sc.vlog_num, sc.value_offset, &vlog_value);
   *value = vlog_value;
+  std::cout << "value from value_log: " << vlog_value << std::endl;
   // TODO(end)
   return s;
 }
@@ -1218,30 +1223,36 @@ void DBImpl::ReleaseSnapshot(const Snapshot* snapshot) {
 }
 
 // Convenience methods
-Status DBImpl::Put(const WriteOptions& o, const Slice& key, const Slice& val) {
+Status DBImpl::Put_Fields(const WriteOptions& opt, const Slice& key,
+                          const FieldArray& fields) {
   // TODO(begin): allocate slot_num in slotpage and put value in vlog
-
+  // 将字段数组序列化
+  std::string serialized_value = SerializeValue(fields);
+  std::cout << "Put_Fields: " << key.ToString() << " " << serialized_value << std::endl;
   size_t slot_num = slot_page_->alloc_slot();
   struct slot_content sc;
-  vlog_set_->put_value(&sc.vlog_num, &sc.value_offset, val);
+  vlog_set_->put_value(&sc.vlog_num, &sc.value_offset, serialized_value);
   slot_page_->set_slot(slot_num, &sc);
 
   char data[sizeof(size_t)];
   memcpy(data, &slot_num, sizeof(size_t));
   Slice slot_val(data, sizeof(data));
 
-  return DB::Put(o, key, slot_val);
+  return DB::Put(opt, key, slot_val);
   // TODO(end)
 }
+Status DBImpl::Put(const WriteOptions& o, const Slice& key, const Slice& val) {
+  return DB::Put(o, key, val);
+}
 
 Status DBImpl::Delete(const WriteOptions& options, const Slice& key) {
-  // TODO(begin)
 //  size_t slot_num = *(size_t *)value->c_str();
 //  struct slot_content sc;
 //  std::string vlog_value;
 //  slot_page_->get_slot(slot_num, &sc);
 //  vlog_set_->get_value(sc.vlog_num, sc.value_offset, &vlog_value);
 //  *value = vlog_value;
+  // TODO(begin)
   ReadOptions ro;
   ro.verify_checksums = true;
   ro.fill_cache = false;
@@ -1537,7 +1548,32 @@ void DBImpl::GetApproximateSizes(const Range* range, int n, uint64_t* sizes) {
 
   v->Unref();
 }
-
+std::string DBImpl::SerializeValue(const FieldArray& fields) {
+  // 创建并初始化一个字符串流 oss,用于逐步构建最终的序列化字符串
+  std::ostringstream oss_temp;
+  std::string slot_num = "slot_num";
+  oss_temp << std::setw(sizeof(size_t)) << std::setfill('0') << slot_num;
+  // 写入属性个数（定长,16比特），使用std::setw(16)设置宽度，使用std::setfull(0)设置填充字符，将字段数组的大小写入oss中
+  oss_temp << std::setw(16) << std::setfill('0') << fields.size();
+  for (const auto& field : fields) {
+    // 写入属性名长度（定长,16比特）
+    oss_temp << std::setw(16) << std::setfill('0') << field.name.size();
+    // 写入属性名（变长）
+    oss_temp << field.name;
+    // 写入属性值长度（定长,16比特）
+    oss_temp << std::setw(16) << std::setfill('0') << field.value.size();
+    // 写入属性值（变长）
+    oss_temp << field.value;
+  }
+  std::string temp_str = oss_temp.str();
+  size_t value_length = temp_str.size();
+
+  std::ostringstream oss;
+  oss << std::setw(16) << std::setfill('0') << value_length;
+  oss << temp_str;
+
+  return oss.str();
+}
 // Default implementations of convenience methods that subclasses of DB
 // can call if they wish
 Status DB::Put(const WriteOptions& opt, const Slice& key, const Slice& value) {

db/db_impl.h

@@ -37,10 +37,16 @@ class DBImpl : public DB {
   DBImpl& operator=(const DBImpl&) = delete;
 
   ~DBImpl() override;
-
+  // Todo(begin)
+  using FieldArray = std::vector<Field>;
+  // Todo(end)
   // Implementations of the DB interface
   Status Put(const WriteOptions&, const Slice& key,
              const Slice& value) override;
+  // Todo(begin)
+  Status Put_Fields(const WriteOptions& opt, const Slice& key,
+                    const FieldArray& fields) override;
+  // Todo(end)
   Status Delete(const WriteOptions&, const Slice& key) override;
   Status Write(const WriteOptions& options, WriteBatch* updates) override;
   Status Get(const ReadOptions& options, const Slice& key,
@@ -81,6 +87,7 @@ class DBImpl : public DB {
   // TODO(begin)
   SlotPage *slot_page_;
   VlogSet *vlog_set_;
+  static std::string SerializeValue(const FieldArray& fields);
   // TODO(end)
   // Information for a manual compaction
   struct ManualCompaction {

include/leveldb/db.h

@@ -7,6 +7,7 @@
 
 #include <cstdint>
 #include <cstdio>
+#include <vector>
 
 #include "leveldb/export.h"
 #include "leveldb/iterator.h"
@@ -21,6 +22,13 @@ static const int kMinorVersion = 23;
 struct Options;
 struct ReadOptions;
 struct WriteOptions;
+// Todo(begin)
+struct Field {
+  std::string name;
+  std::string value;
+};
+using FieldArray = std::vector<Field>;
+// Todo(end)
 class WriteBatch;
 
 // Abstract handle to particular state of a DB.
@@ -145,6 +153,10 @@ class LEVELDB_EXPORT DB {
   // Therefore the following call will compact the entire database:
   //    db->CompactRange(nullptr, nullptr);
   virtual void CompactRange(const Slice* begin, const Slice* end) = 0;
+  // 字段信息结构体
+  // Todo(begin)
+  virtual Status Put_Fields(const leveldb::WriteOptions& opt, const leveldb::Slice& key, const FieldArray& fields) = 0;
+  //  // Todo(end)
 };
 
 // Destroy the contents of the specified database.

test/db_test3.cc

@@ -13,14 +13,6 @@
 #include "gtest/gtest.h"
 
 using namespace leveldb;
-
-// 字段信息结构体
-struct Field {
-  std::string name;
-  std::string value;
-};
-using FieldArray = std::vector<Field>;
-
 // 序列化函数，将字段数组编码为字符串
 std::string SerializeValue(const FieldArray& fields) {
   // 创建并初始化一个字符串流 oss,用于逐步构建最终的序列化字符串
@@ -206,13 +198,9 @@ TEST(TestSchema, Basic) {
       {"address", "ecnu"},
       {"phone", "11111"}
   };
-  // 序列化并插入
-  std::string value1 = SerializeValue(fields1);
-  std::string value2 = SerializeValue(fields2);
-  std::string value3 = SerializeValue(fields3);
-  db->Put(leveldb::WriteOptions(), key1, value1);
-  db->Put(leveldb::WriteOptions(), key2, value2);
-  db->Put(leveldb::WriteOptions(), key3, value3);
+  db->Put_Fields(leveldb::WriteOptions(), key1, fields1);
+  db->Put_Fields(leveldb::WriteOptions(), key2, fields2);
+  db->Put_Fields(leveldb::WriteOptions(), key3, fields3);
 
   // 读取并反序列化
   std::string value_ret;