feat: manually mirror opencoze's code from bytedance

Change-Id: I09a73aadda978ad9511264a756b2ce51f5761adf

backend/domain/workflow/internal/nodes/stream.go

@@ -0,0 +1,185 @@
+/*
+ * 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 nodes
+
+import (
+	"context"
+
+	"github.com/cloudwego/eino/compose"
+
+	"github.com/coze-dev/coze-studio/backend/domain/workflow/entity/vo"
+)
+
+var KeyIsFinished = "\x1FKey is finished\x1F"
+
+type Mode string
+
+const (
+	Streaming    Mode = "streaming"
+	NonStreaming Mode = "non-streaming"
+)
+
+type FieldStreamType string
+
+const (
+	FieldIsStream    FieldStreamType = "yes"     // absolutely a stream
+	FieldNotStream   FieldStreamType = "no"      // absolutely not a stream
+	FieldMaybeStream FieldStreamType = "maybe"   // maybe a stream, requires request-time resolution
+	FieldSkipped     FieldStreamType = "skipped" // the field source's node is skipped
+)
+
+// SourceInfo contains stream type for a input field source of a node.
+type SourceInfo struct {
+	// IsIntermediate means this field is itself not a field source, but a map containing one or more field sources.
+	IsIntermediate bool
+	// FieldType the stream type of the field. May require request-time resolution in addition to compile-time.
+	FieldType FieldStreamType
+	// FromNodeKey is the node key that produces this field source. empty if the field is a static value or variable.
+	FromNodeKey vo.NodeKey
+	// FromPath is the path of this field source within the source node. empty if the field is a static value or variable.
+	FromPath compose.FieldPath
+	TypeInfo *vo.TypeInfo
+	// SubSources are SourceInfo for keys within this intermediate Map(Object) field.
+	SubSources map[string]*SourceInfo
+}
+
+type DynamicStreamContainer interface {
+	SaveDynamicChoice(nodeKey vo.NodeKey, groupToChoice map[string]int)
+	GetDynamicChoice(nodeKey vo.NodeKey) map[string]int
+	GetDynamicStreamType(nodeKey vo.NodeKey, group string) (FieldStreamType, error)
+	GetAllDynamicStreamTypes(nodeKey vo.NodeKey) (map[string]FieldStreamType, error)
+}
+
+// ResolveStreamSources resolves incoming field sources for a node, deciding their stream type.
+func ResolveStreamSources(ctx context.Context, sources map[string]*SourceInfo) (map[string]*SourceInfo, error) {
+	resolved := make(map[string]*SourceInfo, len(sources))
+
+	nodeKey2Skipped := make(map[vo.NodeKey]bool)
+
+	var resolver func(path string, sInfo *SourceInfo) (*SourceInfo, error)
+	resolver = func(path string, sInfo *SourceInfo) (*SourceInfo, error) {
+		resolvedNode := &SourceInfo{
+			IsIntermediate: sInfo.IsIntermediate,
+			FieldType:      sInfo.FieldType,
+			FromNodeKey:    sInfo.FromNodeKey,
+			FromPath:       sInfo.FromPath,
+			TypeInfo:       sInfo.TypeInfo,
+		}
+
+		if len(sInfo.SubSources) > 0 {
+			resolvedNode.SubSources = make(map[string]*SourceInfo, len(sInfo.SubSources))
+
+			for k, subInfo := range sInfo.SubSources {
+				resolvedSub, err := resolver(k, subInfo)
+				if err != nil {
+					return nil, err
+				}
+
+				resolvedNode.SubSources[k] = resolvedSub
+			}
+
+			return resolvedNode, nil
+		}
+
+		if sInfo.FromNodeKey == "" { // static values and variables, always non-streaming and available
+			return resolvedNode, nil
+		}
+
+		var skipped, ok bool
+		if skipped, ok = nodeKey2Skipped[sInfo.FromNodeKey]; !ok {
+			_ = compose.ProcessState(ctx, func(ctx context.Context, state NodeExecuteStatusAware) error {
+				skipped = !state.NodeExecuted(sInfo.FromNodeKey)
+				return nil
+			})
+			nodeKey2Skipped[sInfo.FromNodeKey] = skipped
+		}
+
+		if skipped {
+			resolvedNode.FieldType = FieldSkipped
+			return resolvedNode, nil
+		}
+
+		if sInfo.FieldType == FieldMaybeStream {
+			if len(sInfo.SubSources) > 0 {
+				panic("a maybe stream field should not have sub sources")
+			}
+
+			var streamType FieldStreamType
+			err := compose.ProcessState(ctx, func(ctx context.Context, state DynamicStreamContainer) error {
+				var e error
+				streamType, e = state.GetDynamicStreamType(sInfo.FromNodeKey, sInfo.FromPath[0])
+				return e
+			})
+			if err != nil {
+				return nil, err
+			}
+
+			return &SourceInfo{
+				IsIntermediate: sInfo.IsIntermediate,
+				FieldType:      streamType,
+				FromNodeKey:    sInfo.FromNodeKey,
+				FromPath:       sInfo.FromPath,
+				SubSources:     sInfo.SubSources,
+				TypeInfo:       sInfo.TypeInfo,
+			}, nil
+		}
+
+		return resolvedNode, nil
+	}
+
+	for k, sInfo := range sources {
+		resolvedInfo, err := resolver(k, sInfo)
+		if err != nil {
+			return nil, err
+		}
+		resolved[k] = resolvedInfo
+	}
+
+	return resolved, nil
+}
+
+type NodeExecuteStatusAware interface {
+	NodeExecuted(key vo.NodeKey) bool
+}
+
+func (s *SourceInfo) Skipped() bool {
+	if !s.IsIntermediate {
+		return s.FieldType == FieldSkipped
+	}
+
+	for _, sub := range s.SubSources {
+		if !sub.Skipped() {
+			return false
+		}
+	}
+
+	return true
+}
+
+func (s *SourceInfo) FromNode(nodeKey vo.NodeKey) bool {
+	if !s.IsIntermediate {
+		return s.FromNodeKey == nodeKey
+	}
+
+	for _, sub := range s.SubSources {
+		if sub.FromNode(nodeKey) {
+			return true
+		}
+	}
+
+	return false
+}