rewriteHEADmaster

1 files changed, 203 insertions, 0 deletions

diff --git a/internal/core/core.go b/internal/core/core.go
new file mode 100644
index 0000000..34718bd
--- /dev/null
+++ b/internal/core/core.go
@@ -0,0 +1,203 @@
+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
+}