1// Copyright 2021 Google LLC
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//      http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package compliance
16
17import (
18	"fmt"
19)
20
21// SourceSharePrivacyConflict describes an individual conflict between a source-sharing
22// condition and a source privacy condition
23type SourceSharePrivacyConflict struct {
24	SourceNode       *TargetNode
25	ShareCondition   LicenseCondition
26	PrivacyCondition LicenseCondition
27}
28
29// Error returns a string describing the conflict.
30func (conflict SourceSharePrivacyConflict) Error() string {
31	return fmt.Sprintf("%s %s and must share from %s condition\n", conflict.SourceNode.name,
32		conflict.PrivacyCondition.Name(), conflict.ShareCondition.Name())
33}
34
35// IsEqualTo returns true when `conflict` and `other` describe the same conflict.
36func (conflict SourceSharePrivacyConflict) IsEqualTo(other SourceSharePrivacyConflict) bool {
37	return conflict.SourceNode.name == other.SourceNode.name &&
38		conflict.ShareCondition == other.ShareCondition &&
39		conflict.PrivacyCondition == other.PrivacyCondition
40}
41
42// ConflictingSharedPrivateSource lists all of the targets where conflicting conditions to
43// share the source and to keep the source private apply to the target.
44func ConflictingSharedPrivateSource(lg *LicenseGraph) []SourceSharePrivacyConflict {
45
46	ResolveTopDownConditions(lg)
47	// combined is the combination of source-sharing and source privacy.
48	combined := WalkActionsForCondition(lg, ImpliesShared.Union(ImpliesPrivate))
49
50	// size is the size of the result
51	size := 0
52	for actsOn, cs := range combined {
53		if actsOn.pure && !actsOn.LicenseConditions().MatchesAnySet(ImpliesShared) {
54			// no need to share code to build "a distribution medium"
55			continue
56		}
57		size += cs.Intersection(ImpliesShared).Len() * cs.Intersection(ImpliesPrivate).Len()
58	}
59	if size == 0 {
60		return nil
61	}
62	result := make([]SourceSharePrivacyConflict, 0, size)
63	for actsOn, cs := range combined {
64		if actsOn.pure { // no need to share code for "a distribution medium"
65			continue
66		}
67		pconditions := cs.Intersection(ImpliesPrivate).AsList()
68		ssconditions := cs.Intersection(ImpliesShared).AsList()
69
70		// report all conflicting condition combinations
71		for _, p := range pconditions {
72			for _, ss := range ssconditions {
73				result = append(result, SourceSharePrivacyConflict{actsOn, ss, p})
74			}
75		}
76	}
77	return result
78}
79