This repository was archived by the owner on Nov 6, 2020. It is now read-only.
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathLocalCache.swift
More file actions
135 lines (114 loc) · 4.04 KB
/
LocalCache.swift
File metadata and controls
135 lines (114 loc) · 4.04 KB
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
//
// LocalCache.swift
//
// Copyright (c) 2015, Bitten Apps
// All rights reserved.
//
// Redistribution and use in source and binary forms,
// with or without modification, are permitted provided
// that the following conditions are met:
//
// 1. Redistributions of source code must retain the above
// copyright notice, this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
// COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
// ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
import UIKit
class CachedObject<Type> {
var timestamp : NSTimeInterval
var identifier : String
var object : Type
convenience init(identifier: String, object: Type) {
self.init(timestamp: NSDate().timeIntervalSinceReferenceDate, identifier: identifier, object: object)
}
init(timestamp: NSTimeInterval, identifier: String, object: Type) {
self.timestamp = timestamp
self.identifier = identifier
self.object = object
}
}
enum LocalCacheError : ErrorType {
case IdentifierAlreadyExists
case ObjectNotFound
}
class LocalCache<Type> {
private var cache : [CachedObject<Type>]
var expiry : Int
init(secondsToExpiration: Int) {
cache = [CachedObject<Type>]()
expiry = secondsToExpiration
}
func getObject(id: String) -> Type? {
for obj in cache {
if obj.identifier == id {
if isUseable(obj) {
return obj.object
} else {
try! removeObject(obj)
return nil
}
}
}
return nil
}
func addObject(object: CachedObject<Type>) throws {
if hasObject(withIdentifier: object.identifier) {
if isUseable(object) {
throw LocalCacheError.IdentifierAlreadyExists
} else {
try removeObject(object)
}
}
cache.append(object)
}
func removeObject(object: CachedObject<Type>) throws {
for (idx, item) in cache.enumerate() {
if item.identifier == object.identifier {
cache.removeAtIndex(idx)
return
}
}
throw LocalCacheError.ObjectNotFound
}
func purgeExpiredObjects() {
for o in cache {
if !isUseable(o) {
try! removeObject(o)
}
}
}
func hasObject(withIdentifier id: String) -> Bool {
for obj in cache {
if obj.identifier == id && isUseable(obj) {
return true
}
}
return false
}
func isUseable(object: CachedObject<Type>) -> Bool {
if Int(object.timestamp) + expiry > Int(NSDate().timeIntervalSinceReferenceDate) {
return true
} else {
return false
}
}
}