forked from GoogleCloudPlatform/gcsfuse
/
symlink.go
151 lines (125 loc) · 3.33 KB
/
symlink.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
150
151
// Copyright 2015 Google Inc. 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 inode
import (
"sync"
"github.com/Tulsishah/gcsfuse-tulsishah7/internal/storage/gcs"
"github.com/jacobsa/fuse/fuseops"
"golang.org/x/net/context"
)
// When this custom metadata key is present in an object record, it is to be
// treated as a symlink. For use in testing only; other users should detect
// this with IsSymlink.
const SymlinkMetadataKey = "gcsfuse_symlink_target"
// IsSymlink Does the supplied object represent a symlink inode?
func IsSymlink(m *gcs.MinObject) bool {
if m == nil {
return false
}
_, ok := m.Metadata[SymlinkMetadataKey]
return ok
}
type SymlinkInode struct {
/////////////////////////
// Constant data
/////////////////////////
id fuseops.InodeID
name Name
sourceGeneration Generation
attrs fuseops.InodeAttributes
target string
/////////////////////////
// Mutable state
/////////////////////////
mu sync.Mutex
// GUARDED_BY(mu)
lc lookupCount
}
var _ Inode = &SymlinkInode{}
// Create a symlink inode for the supplied object record.
//
// REQUIRES: IsSymlink(o)
func NewSymlinkInode(
id fuseops.InodeID,
name Name,
m *gcs.MinObject,
attrs fuseops.InodeAttributes) (s *SymlinkInode) {
// Create the inode.
s = &SymlinkInode{
id: id,
name: name,
sourceGeneration: Generation{
Object: m.Generation,
Metadata: m.MetaGeneration,
},
attrs: fuseops.InodeAttributes{
Nlink: 1,
Uid: attrs.Uid,
Gid: attrs.Gid,
Mode: attrs.Mode,
Atime: m.Updated,
Ctime: m.Updated,
Mtime: m.Updated,
},
target: m.Metadata[SymlinkMetadataKey],
}
// Set up lookup counting.
s.lc.Init(id)
return
}
////////////////////////////////////////////////////////////////////////
// Public interface
////////////////////////////////////////////////////////////////////////
func (s *SymlinkInode) Lock() {
s.mu.Lock()
}
func (s *SymlinkInode) Unlock() {
s.mu.Unlock()
}
func (s *SymlinkInode) ID() fuseops.InodeID {
return s.id
}
func (s *SymlinkInode) Name() Name {
return s.name
}
// SourceGeneration returns the object generation from which this inode was branched.
//
// LOCKS_REQUIRED(s)
func (s *SymlinkInode) SourceGeneration() Generation {
return s.sourceGeneration
}
// LOCKS_REQUIRED(s.mu)
func (s *SymlinkInode) IncrementLookupCount() {
s.lc.Inc()
}
// LOCKS_REQUIRED(s.mu)
func (s *SymlinkInode) DecrementLookupCount(n uint64) (destroy bool) {
destroy = s.lc.Dec(n)
return
}
// LOCKS_REQUIRED(s.mu)
func (s *SymlinkInode) Destroy() (err error) {
// Nothing to do.
return
}
func (s *SymlinkInode) Attributes(
ctx context.Context) (attrs fuseops.InodeAttributes, err error) {
attrs = s.attrs
return
}
// Target returns the target of the symlink.
func (s *SymlinkInode) Target() (target string) {
target = s.target
return
}