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package core
import (
"context"
"fmt"
"strconv"
"sync"
"github.com/dgraph-io/badger/v3"
"github.com/vmihailenco/msgpack/v5"
"go.neonxp.dev/djson/internal/command"
"go.neonxp.dev/djson/internal/node"
"go.neonxp.dev/json"
)
type Core struct {
storage *badger.DB
root *node.Node
mu sync.RWMutex
json *json.JSON
}
func New(storage *badger.DB) *Core {
return &Core{
storage: storage,
root: nil,
json: json.New(node.Factory),
}
}
func (c *Core) Init(ctx context.Context) error {
return c.storage.View(func(txn *badger.Txn) error {
opts := badger.DefaultIteratorOptions
opts.PrefetchSize = 10
it := txn.NewIterator(opts)
defer it.Close()
for it.Rewind(); it.Valid(); it.Next() {
item := it.Item()
err := item.Value(func(v []byte) error {
mut := &command.Mutation{}
if err := msgpack.Unmarshal(v, mut); err != nil {
return err
}
return c.apply(ctx, mut)
})
if err != nil {
return err
}
}
return nil
})
}
func (c *Core) Apply(ctx context.Context, mutation *command.Mutation) error {
return c.storage.Update(func(txn *badger.Txn) error {
if err := c.apply(ctx, mutation); err != nil {
return err
}
mb, err := msgpack.Marshal(mutation)
if err != nil {
return err
}
e := &badger.Entry{
Key: mutation.ID,
Value: mb,
}
return txn.SetEntry(e)
})
}
func (c *Core) apply(ctx context.Context, mutation *command.Mutation) error {
c.mu.Lock()
defer c.mu.Unlock()
switch mutation.Type {
case command.Create:
n, err := c.json.Unmarshal(mutation.Data)
if err != nil {
return err
}
if err := c.create(mutation.Path, n.(*node.Node)); err != nil {
return err
}
case command.Merge:
n, err := c.json.Unmarshal(mutation.Data)
if err != nil {
return err
}
if err := c.merge(mutation.Path, n.(*node.Node)); err != nil {
return err
}
case command.Remove:
if err := c.remove(mutation.Path); err != nil {
return err
}
}
return nil
}
func (c *Core) Query(ctx context.Context, query []string) (json.Node, error) {
return json.Query(c.root, query)
}
func (c *Core) create(path []string, n *node.Node) error {
if len(path) == 0 {
c.root = n
return nil
}
path, last := path[:len(path)-1], path[len(path)-1]
parent, err := json.Query(c.root, path)
if err != nil {
return fmt.Errorf("parent node not found")
}
parentNode, ok := parent.(*node.Node)
if !ok {
return fmt.Errorf("invalid node")
}
switch parentNode.Type {
case json.ArrayType:
if last == "[]" {
parentNode.Append(n)
return nil
}
idx, err := strconv.Atoi(last)
if err != nil {
return fmt.Errorf("cant use %s as array index", last)
}
if idx < 0 || idx >= parentNode.Len() {
return fmt.Errorf("index %d out of bounds [0, %d]", idx, parentNode.Len()-1)
}
parentNode.SetByIndex(idx, n)
case json.ObjectType:
parentNode.SetKeyValue(last, n)
default:
return fmt.Errorf("cant add node to node of type %s", parentNode.Type)
}
return nil
}
func (c *Core) merge(path []string, n *node.Node) error {
parent, err := json.Query(c.root, path)
if err != nil {
return fmt.Errorf("parent node not found")
}
parentNode, ok := parent.(*node.Node)
if !ok {
return fmt.Errorf("invalid node")
}
if n.Type != parentNode.Type {
return fmt.Errorf("merging nodes must be same type")
}
switch n.Type {
case json.ObjectType:
parentNode.Merge(n)
case json.ArrayType:
for i := 0; i < n.Len(); i++ {
parentNode.Append(n.Index(i))
}
default:
return fmt.Errorf("can merge only objects or arrays")
}
return nil
}
func (c *Core) remove(path []string) error {
if len(path) == 0 {
c.root = nil
return nil
}
path, last := path[:len(path)-1], path[len(path)-1]
parent, err := json.Query(c.root, path)
if err != nil {
return fmt.Errorf("parent node not found")
}
parentNode, ok := parent.(*node.Node)
if !ok {
return fmt.Errorf("invalid node")
}
switch parentNode.Type {
case json.ObjectType:
parentNode.RemoveByKey(last)
case json.ArrayType:
idx, err := strconv.Atoi(last)
if err != nil {
return fmt.Errorf("cant use %s as array index", last)
}
if idx < 0 || idx >= parentNode.Len() {
return fmt.Errorf("index %d out of bounds [0, %d]", idx, parentNode.Len()-1)
}
parentNode.RemoveByIndex(idx)
default:
return fmt.Errorf("can remove children only from object or array")
}
return nil
}
|
