fix save structure

kvstore.go

@@ -2,9 +2,12 @@ package gocache
 
 import (
 	"bytes"
+	"encoding/binary"
 	"encoding/json"
+	"fmt"
 	"os"
 	"sync"
+	"time"
 )
 
 // KVStore represents a simple in-memory key/value store.
@@ -13,7 +16,11 @@ type KVStore struct {
 	store       map[string]string
 	file        string
 	transaction *Transaction
-	logFile     string // 添加日志文件路径
+	logFile     string
+	memoryLimit int64
+	memoryUsage int64
+	dirtyKeys   map[string]bool // 记录发生变化的Key
+	bucketCount int             // 哈希桶数量
 }
 
 // Transaction represents an ongoing transaction
@@ -22,149 +29,103 @@ type Transaction struct {
 }
 
 // NewKVStore creates a new instance of KVStore.
-func NewKVStore(file string) *KVStore {
+func NewKVStore(file string, memoryLimit int64, bucketCount int) *KVStore {
 	store := &KVStore{
 		store:       make(map[string]string),
 		file:        file,
 		logFile:     file + ".log",
+		memoryLimit: memoryLimit,
+		memoryUsage: 0,
+		dirtyKeys:   make(map[string]bool),
+		bucketCount: bucketCount,
 	}
 	// 启动时自动恢复日志
 	if err := store.RecoverFromLog(); err != nil {
 		panic(err)
 	}
+	// 启动定时器，定期存储变化
+	go store.periodicSave()
 	return store
 }
 
-// RecoverFromLog recovers data from log file
-func (k *KVStore) RecoverFromLog() error {
+// periodicSave periodically saves dirty keys to file and clears the log
+func (k *KVStore) periodicSave() {
+	ticker := time.NewTicker(5 * time.Minute) // 每5分钟保存一次
+	for range ticker.C {
 		k.mu.Lock()
-	defer k.mu.Unlock()
-
-	// 检查日志文件是否存在
-	if _, err := os.Stat(k.logFile); os.IsNotExist(err) {
-		return nil
+		if len(k.dirtyKeys) > 0 {
+			// 保存变化到文件
+			for key := range k.dirtyKeys {
+				k.saveKeyToBucket(key)
 			}
-
-	// 读取日志文件
-	data, err := os.ReadFile(k.logFile)
-	if err != nil {
-		return err
-	}
-
-	// 逐行处理日志
-	lines := bytes.Split(data, []byte{'\n'})
-	for _, line := range lines {
-		if len(line) ==  {
-			continue
-		}
-		var logEntry map[string]string
-		if err := json.Unmarshal(line, &logEntry); err != nil {
-			return err
-		}
-		switch logEntry["op"] {
-		case "put":
-			k.store[logEntry["key"]] = logEntry["value"]
-		case "delete":
-			delete(k.store, logEntry["key"])
-		}
-	}
-
+			// 清空dirtyKeys
+			k.dirtyKeys = make(map[string]bool)
 			// 清空日志文件
-	return os.Truncate(k.logFile, 0)
+			os.Truncate(k.logFile, 0)
+		}
+		k.mu.Unlock()
+	}
 }
 
-// SaveToFile saves the current store to a file.
-func (k *KVStore) SaveToFile() error {
-	k.mu.RLock()
-	defer k.mu.RUnlock()
-	data, err := json.Marshal(k.store)
+// saveKeyToBucket saves a key to its corresponding bucket file
+func (k *KVStore) saveKeyToBucket(key string) error {
+	// 计算哈希值确定桶
+	hash := hashKey(key) % k.bucketCount
+	bucketFile := fmt.Sprintf("%s.bucket%d", k.file, hash)
+
+	file, err := os.OpenFile(bucketFile, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
 	if err != nil {
 		return err
 	}
-	return os.WriteFile(k.file, data, 0644)
-}
+	defer file.Close()
 
-// LogOperation logs a key/value operation to the log file
-func (k *KVStore) LogOperation(op string, key, value string) error {
-	logEntry := map[string]string{
-		"op":    op,
-		"key":   key,
-		"value": value,
+	value, exists := k.store[key]
+	if !exists {
+		return nil
 	}
-	data, err := json.Marshal(logEntry)
-	if err != nil {
+
+	// 写入键长度和键
+	if err := binary.Write(file, binary.LittleEndian, int64(len(key))); err != nil {
 		return err
 	}
-	data = append(data, '\n')
-	f, err := os.OpenFile(k.logFile, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
-	if err != nil {
-		return err
-	}
-	defer f.Close()
-	_, err = f.Write(data)
-	return err
-}
-
-// LoadFromFile loads the store from a file with partial loading support
-func (k *KVStore) LoadFromFile(keys ...string) error {
-	k.mu.Lock()
-	defer k.mu.Unlock()
-
-	// 先加载主数据文件
-	if _, err := os.Stat(k.file); err == nil {
-		data, err := os.ReadFile(k.file)
-		if err != nil {
+	if _, err := file.WriteString(key); err != nil {
 		return err
 	}
 
-		var tempStore map[string]string
-		if err := json.Unmarshal(data, &tempStore); err != nil {
+	// 写入值长度和值
+	if err := binary.Write(file, binary.LittleEndian, int64(len(value))); err != nil {
 		return err
 	}
-
-		// Partial loading
-		if len(keys) > 0 {
-			for _, key := range keys {
-				if value, exists := tempStore[key]; exists {
-					k.store[key] = value
-				}
-			}
-		}
-	}
-
-	// 然后应用日志文件中的操作
-	if _, err := os.Stat(k.logFile); err == nil {
-		data, err := os.ReadFile(k.logFile)
-		if err != nil {
+	if _, err := file.WriteString(value); err != nil {
 		return err
 	}
 
-		lines := bytes.Split(data, []byte{'\n'})
-		for _, line := range lines {
-			if len(line) == 0 {
-				continue
-			}
-			var logEntry map[string]string
-			if err := json.Unmarshal(line, &logEntry); err != nil {
-				return err
-			}
-			switch logEntry["op"] {
-			case "put":
-				k.store[logEntry["key"]] = logEntry["value"]
-			case "delete":
-				delete(k.store, logEntry["key"])
-			}
-		}
-	}
-
 	return nil
 }
 
+// hashKey computes a hash for the key
+func hashKey(key string) int {
+	hash := 0
+	for _, char := range key {
+		hash = 31*hash + int(char)
+	}
+	return hash
+}
+
 // Put adds a key/value pair to the store.
 func (k *KVStore) Put(key, value string) {
 	k.mu.Lock()
 	defer k.mu.Unlock()
+
+	// 检查内存使用量
+	newMemoryUsage := k.memoryUsage + int64(len(key)+len(value))
+	if newMemoryUsage > k.memoryLimit {
+		panic("Memory limit exceeded")
+	}
+
 	k.store[key] = value
+	k.memoryUsage = newMemoryUsage
+	k.dirtyKeys[key] = true
 	go func() {
 		k.mu.Lock()
 		defer k.mu.Unlock()
@@ -172,6 +133,23 @@ func (k *KVStore) Put(key, value string) {
 	}()
 }
 
+// Delete removes the key/value pair associated with the given key.
+func (k *KVStore) Delete(key string) {
+	k.mu.Lock()
+	defer k.mu.Unlock()
+
+	if value, exists := k.store[key]; exists {
+		delete(k.store, key)
+		k.memoryUsage -= int64(len(key) + len(value))
+		k.dirtyKeys[key] = true
+		go func() {
+			k.mu.Lock()
+			defer k.mu.Unlock()
+			k.LogOperation("delete", key, "") // 异步记录操作日志
+		}()
+	}
+}
+
 // Get retrieves the value associated with the given key.
 func (k *KVStore) Get(key string) (string, bool) {
 	k.mu.RLock()
@@ -186,18 +164,6 @@ func (k *KVStore) Get(key string) (string, bool) {
 	return value, exists
 }
 
-// Delete removes the key/value pair associated with the given key.
-func (k *KVStore) Delete(key string) {
-	k.mu.Lock()
-	defer k.mu.Unlock()
-	delete(k.store, key)
-	go func() {
-		k.mu.Lock()
-		defer k.mu.Unlock()
-		k.LogOperation("delete", key, "") // 异步记录操作日志
-	}()
-}
-
 // BeginTransaction starts a new transaction
 func (k *KVStore) BeginTransaction() {
 	k.mu.Lock()
@@ -239,3 +205,183 @@ func (k *KVStore) PutInTransaction(key, value string) {
 		k.store[key] = value
 	}
 }
+
+// RecoverFromLog recovers data from log file
+func (k *KVStore) RecoverFromLog() error {
+	k.mu.Lock()
+	defer k.mu.Unlock()
+
+	// 检查日志文件是否存在
+	if _, err := os.Stat(k.logFile); os.IsNotExist(err) {
+		return nil
+	}
+
+	// 读取日志文件
+	data, err := os.ReadFile(k.logFile)
+	if err != nil {
+		return err
+	}
+
+	// 逐行处理日志
+	lines := bytes.Split(data, []byte{'\n'})
+	for _, line := range lines {
+		if len(line) == 0 {
+			continue
+		}
+		var logEntry map[string]string
+		if err := json.Unmarshal(line, &logEntry); err != nil {
+			return err
+		}
+		switch logEntry["op"] {
+		case "put":
+			k.store[logEntry["key"]] = logEntry["value"]
+		case "delete":
+			delete(k.store, logEntry["key"])
+		}
+	}
+
+	// 清空日志文件
+	return os.Truncate(k.logFile, 0)
+}
+
+// SaveToFile saves the current store to a file using binary format.
+func (k *KVStore) SaveToFile() error {
+	k.mu.RLock()
+	defer k.mu.RUnlock()
+
+	file, err := os.Create(k.file)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	// 写入键值对数量
+	if err := binary.Write(file, binary.LittleEndian, int64(len(k.store))); err != nil {
+		return err
+	}
+
+	// 逐个写入键值对
+	for key, value := range k.store {
+		// 写入键长度和键
+		if err := binary.Write(file, binary.LittleEndian, int64(len(key))); err != nil {
+			return err
+		}
+		if _, err := file.WriteString(key); err != nil {
+			return err
+		}
+
+		// 写入值长度和值
+		if err := binary.Write(file, binary.LittleEndian, int64(len(value))); err != nil {
+			return err
+		}
+		if _, err := file.WriteString(value); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// LogOperation logs a key/value operation to the log file
+func (k *KVStore) LogOperation(op string, key, value string) error {
+	logEntry := map[string]string{
+		"op":    op,
+		"key":   key,
+		"value": value,
+	}
+	data, err := json.Marshal(logEntry)
+	if err != nil {
+		return err
+	}
+	data = append(data, '\n')
+	f, err := os.OpenFile(k.logFile, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	_, err = f.Write(data)
+	return err
+}
+
+// LoadFromFile loads the store from a file with partial loading support
+func (k *KVStore) LoadFromFile(keys ...string) error {
+	k.mu.Lock()
+	defer k.mu.Unlock()
+
+	// 先加载主数据文件
+	if _, err := os.Stat(k.file); err == nil {
+		file, err := os.Open(k.file)
+		if err != nil {
+			return err
+		}
+		defer file.Close()
+
+		// 读取键值对数量
+		var count int64
+		if err := binary.Read(file, binary.LittleEndian, &count); err != nil {
+			return err
+		}
+
+		// 逐个读取键值对
+		for i := int64(0); i < count; i++ {
+			// 读取键长度和键
+			var keyLen int64
+			if err := binary.Read(file, binary.LittleEndian, &keyLen); err != nil {
+				return err
+			}
+			key := make([]byte, keyLen)
+			if _, err := file.Read(key); err != nil {
+				return err
+			}
+
+			// 读取值长度和值
+			var valueLen int64
+			if err := binary.Read(file, binary.LittleEndian, &valueLen); err != nil {
+				return err
+			}
+			value := make([]byte, valueLen)
+			if _, err := file.Read(value); err != nil {
+				return err
+			}
+
+			// Partial loading
+			if len(keys) == 0 {
+				k.store[string(key)] = string(value)
+			} else {
+				for _, targetKey := range keys {
+					if targetKey == string(key) {
+						k.store[string(key)] = string(value)
+						break
+					}
+				}
+			}
+		}
+	}
+
+	// 然后应用日志文件中的操作
+	if _, err := os.Stat(k.logFile); err == nil {
+		data, err := os.ReadFile(k.logFile)
+		if err != nil {
+			return err
+		}
+
+		lines := bytes.Split(data, []byte{'\n'})
+		for _, line := range lines {
+			if len(line) == 0 {
+				continue
+			}
+			var logEntry map[string]string
+			if err := json.Unmarshal(line, &logEntry); err != nil {
+				return err
+			}
+			switch logEntry["op"] {
+			case "put":
+				k.store[logEntry["key"]] = logEntry["value"]
+			case "delete":
+				delete(k.store, logEntry["key"])
+			}
+		}
+	}
+
+	return nil
+}

kvstore_test.go

@@ -5,15 +5,18 @@ import (
 	"testing"
 )
 
+var mumlimit int64 = 1024 * 1024 * 1024
+var bucketCount = 16
+
 func TestNewKVStore(t *testing.T) {
-	store := NewKVStore("test.db")
+	store := NewKVStore("test.db", mumlimit, bucketCount)
 	if store == nil {
 		t.Error("Expected a new KVStore instance, got nil")
 	}
 }
 
 func TestPutAndGet(t *testing.T) {
-	store := NewKVStore("test.db")
+	store := NewKVStore("test.db", mumlimit, bucketCount)
 	store.Put("key1", "value1")
 	value, exists := store.Get("key1")
 	if !exists || value != "value1" {
@@ -22,7 +25,7 @@ func TestPutAndGet(t *testing.T) {
 }
 
 func TestDelete(t *testing.T) {
-	store := NewKVStore("test.db")
+	store := NewKVStore("test.db", mumlimit, bucketCount)
 	store.Put("key1", "value1")
 	store.Delete("key1")
 	_, exists := store.Get("key1")
@@ -32,14 +35,14 @@ func TestDelete(t *testing.T) {
 }
 
 func TestSaveAndLoadFromFile(t *testing.T) {
-	store := NewKVStore("test.db")
+	store := NewKVStore("test.db", mumlimit, bucketCount)
 	store.Put("key1", "value1")
 	err := store.SaveToFile()
 	if err != nil {
 		t.Error("Failed to save store to file")
 	}
 
-	newStore := NewKVStore("test.db")
+	newStore := NewKVStore("test.db", mumlimit, bucketCount)
 	err = newStore.LoadFromFile()
 	if err != nil {
 		t.Error("Failed to load store from file")
@@ -56,7 +59,7 @@ func TestSaveAndLoadFromFile(t *testing.T) {
 }
 
 func TestLogOperation(t *testing.T) {
-	store := NewKVStore("test.db")
+	store := NewKVStore("test.db", mumlimit, bucketCount)
 	err := store.LogOperation("put", "key1", "value1")
 	if err != nil {
 		t.Error("Failed to log operation")
@@ -67,7 +70,7 @@ func TestLogOperation(t *testing.T) {
 }
 
 func TestTransaction(t *testing.T) {
-	store := NewKVStore("test.db")
+	store := NewKVStore("test.db", mumlimit, bucketCount)
 	store.BeginTransaction()
 	store.PutInTransaction("key1", "value1")
 	store.Commit()