-
Notifications
You must be signed in to change notification settings - Fork 1.3k
/
session.go
149 lines (133 loc) · 3.29 KB
/
session.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
// Copyright 2014 The Cayley Authors. All rights reserved.
//
// 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 mql
import (
"context"
"encoding/json"
"github.com/cayleygraph/cayley/graph"
"github.com/cayleygraph/cayley/graph/iterator"
"github.com/cayleygraph/cayley/query"
)
const Name = "mql"
func init() {
query.RegisterLanguage(query.Language{
Name: Name,
Session: func(qs graph.QuadStore) query.Session {
return NewSession(qs)
},
HTTP: func(qs graph.QuadStore) query.HTTP {
return NewSession(qs)
},
REPL: func(qs graph.QuadStore) query.REPLSession {
return NewSession(qs)
},
})
}
type Session struct {
qs graph.QuadStore
}
func NewSession(qs graph.QuadStore) *Session {
return &Session{qs: qs}
}
func (s *Session) ShapeOf(query string) (interface{}, error) {
var mqlQuery interface{}
err := json.Unmarshal([]byte(query), &mqlQuery)
if err != nil {
return nil, err
}
q := NewQuery(s)
q.BuildIteratorTree(mqlQuery)
output := make(map[string]interface{})
iterator.OutputQueryShapeForIterator(q.it, s.qs, output)
nodes := make([]iterator.Node, 0)
for _, n := range output["nodes"].([]iterator.Node) {
n.Tags = nil
nodes = append(nodes, n)
}
output["nodes"] = nodes
return output, nil
}
type mqlIterator struct {
q *Query
col query.Collation
it graph.Iterator
res []interface{}
}
func (it *mqlIterator) Next(ctx context.Context) bool {
// TODO: stream results
if it.res != nil {
if len(it.res) == 0 {
return false
}
it.res = it.res[1:]
return len(it.res) != 0
}
for it.it.Next(ctx) {
m := make(map[string]graph.Ref)
it.it.TagResults(m)
it.q.treeifyResult(m)
for it.it.NextPath(ctx) {
m = make(map[string]graph.Ref, len(m))
it.it.TagResults(m)
it.q.treeifyResult(m)
}
}
if err := it.it.Err(); err != nil {
return false
}
it.q.buildResults()
it.res = it.q.results
return len(it.res) != 0
}
func (it *mqlIterator) Result() interface{} {
if len(it.res) == 0 {
return nil
}
return it.res[0]
}
func (it *mqlIterator) Err() error {
return it.it.Err()
}
func (it *mqlIterator) Close() error {
return it.it.Close()
}
func (s *Session) Execute(ctx context.Context, input string, opt query.Options) (query.Iterator, error) {
switch opt.Collation {
case query.REPL, query.JSON:
default:
return nil, &query.ErrUnsupportedCollation{Collation: opt.Collation}
}
var mqlQuery interface{}
if err := json.Unmarshal([]byte(input), &mqlQuery); err != nil {
return nil, err
}
q := NewQuery(s)
q.BuildIteratorTree(mqlQuery)
if q.isError() {
return nil, q.err
}
it := q.it
if opt.Limit > 0 {
it = iterator.NewLimit(it, int64(opt.Limit))
}
return &mqlIterator{
q: q,
col: opt.Collation,
it: it,
}, nil
}
func (s *Session) Clear() {
// Since we create a new Query underneath every query, clearing isn't necessary.
return
}