feat: manually mirror opencoze's code from bytedance

Change-Id: I09a73aadda978ad9511264a756b2ce51f5761adf

backend/infra/impl/document/parser/builtin/parse_csv.go

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2025 coze-dev Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package builtin
+
+import (
+	"context"
+	"encoding/csv"
+	"errors"
+	"io"
+
+	"github.com/cloudwego/eino/components/document/parser"
+	"github.com/cloudwego/eino/schema"
+	"github.com/dimchansky/utfbom"
+
+	contract "github.com/coze-dev/coze-studio/backend/infra/contract/document/parser"
+)
+
+func parseCSV(config *contract.Config) parseFn {
+	return func(ctx context.Context, reader io.Reader, opts ...parser.Option) (docs []*schema.Document, err error) {
+		iter := &csvIterator{csv.NewReader(utfbom.SkipOnly(reader))}
+		return parseByRowIterator(iter, config, opts...)
+	}
+}
+
+type csvIterator struct {
+	reader *csv.Reader
+}
+
+func (c *csvIterator) NextRow() (row []string, end bool, err error) {
+	row, e := c.reader.Read()
+	if e != nil {
+		if errors.Is(e, io.EOF) {
+			return nil, true, nil
+		}
+		return nil, false, err
+	}
+
+	return row, false, nil
+}