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
|
// Copyright (C) 2015 The Android Open Source Project
//
// 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 maker
import (
"log"
"regexp"
"time"
)
// Entity represents an object in the build graph.
type Entity interface {
// Name returns the unique name of this entity.
// If Name is the empty string, the entity does not appear in the main entity
// list and cannot be looked up.
Name() string
// Timestamp returns the last modified time of the entity, or the zero time if
// not available.
Timestamp() time.Time
// NeedsUpdate returns true if the entity requires it's generating step to run.
// The supplied timestamp is the newest timestamp of the entities this one
// depends on, and can be used to decide if an update is neccesary.
NeedsUpdate(t time.Time) bool
// Updated is called when a step that modifies this entity completes.
Updated()
}
var (
entities = map[string]Entity{}
entityHooks = []func(e Entity){}
)
// EntityHook registers a function that is invoked when a new entity is added
// to the system.
func EntityHook(f func(e Entity)) {
entityHooks = append(entityHooks, f)
}
// FindEntity tries to look up an entity by name, and returns nil if the entity
// cannot be found.
func FindEntity(name string) Entity {
if name == "" {
return nil
}
e, _ := entities[name]
return e
}
// FindPathEntity tries to look up an entity by name.
// If an exact match cannot be found, then the name is treated as a path, and
// the absolute path is looked up instead.
// If that also does not match, it returns nil.
func FindPathEntity(name string) Entity {
if e := FindEntity(name); e != nil {
return e
}
if abs, err := OSPath(name); err == nil {
if e := FindEntity(abs); e != nil {
return e
}
}
return nil
}
// FindEntities tries to find all entities who's names match the supplied
// string. The string is treated as a case insensitive regular expression.
func FindEntities(pattern string) []Entity {
re := regexp.MustCompile("(?i)" + pattern)
matches := []Entity{}
for name, e := range entities {
if re.MatchString(name) {
matches = append(matches, e)
}
}
return matches
}
// EntityOf tries to find an entity for the supplied value.
// If the value is an entity, it will be returned directly. If the value is a
// string it will use FindPathEntity to look it up.
// It is an error for v to not match an existing entity.
func EntityOf(v interface{}) Entity {
switch v := v.(type) {
case string:
e := FindPathEntity(v)
if e == nil {
log.Fatalf("no such entity %s", v)
}
return e
case Entity:
return v
default:
log.Fatalf("cannot get entity for %T", v)
return nil
}
}
// AddEntity adds a new entity into the system.
// The entity must not have the same name as an already exixting entity.
func AddEntity(e Entity) {
name := e.Name()
if name != "" {
_, found := entities[name]
if found {
log.Fatalf("Attempt to remap entity name %s", name)
}
entities[name] = e
}
for _, h := range entityHooks {
h(e)
}
}
|
