-
Notifications
You must be signed in to change notification settings - Fork 0
/
importer.go
160 lines (143 loc) · 4.12 KB
/
importer.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
152
153
154
155
156
157
158
159
160
/*
*
* Copyright 2022 indentlang authors.
*
* 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 builtins
import (
"os"
"sync"
"github.com/dvaumoron/indentlang/parser"
"github.com/dvaumoron/indentlang/types"
)
type importRequest struct {
basePath string
filePath string
responder chan<- types.Environment
}
var requestToImporter chan<- importRequest
type importResponse struct {
path string
env types.Environment
}
var responseToImporter chan<- importResponse
func init() {
importChannel := make(chan importRequest)
importChannel2 := make(chan importResponse)
go importer(importChannel, importChannel2)
requestToImporter = importChannel
responseToImporter = importChannel2
}
type moduleCacheValue struct {
env types.Environment
waitings []chan<- types.Environment
loaded bool
}
// don't need mutex (only one coroutine access it)
var moduleCache = map[string]moduleCacheValue{}
func importer(requestReceiver <-chan importRequest, responseReceiver <-chan importResponse) {
for {
select {
case request := <-requestReceiver:
basePath := request.basePath
totalPath := basePath + request.filePath
value := moduleCache[totalPath]
if value.loaded {
responder := request.responder
request.responder <- value.env
close(responder)
} else {
waitings := value.waitings
if len(waitings) == 0 {
// nobody waiting, trying import
go innerImporter(basePath, totalPath)
}
value.waitings = append(waitings, request.responder)
moduleCache[totalPath] = value
}
case response := <-responseReceiver:
path := response.path
env := response.env
// send the imported to all waitings
for _, responder := range moduleCache[path].waitings {
responder <- env
close(responder)
}
// save the computed env & reset the list of waiting
moduleCache[path] = moduleCacheValue{env: env, loaded: true}
}
}
}
const ImportName = "Import"
func innerImporter(basePath, totalPath string) {
env := types.MakeLocalEnvironment(Builtins)
env.StoreStr(ImportName, makeCheckedImportDirective(basePath))
// nested environment to isolate the directive Import, this avoid copying
var local types.Environment
var node types.Object
tmplData, err := os.ReadFile(totalPath)
if err != nil {
goto End
}
node, err = parser.Parse(string(tmplData))
if err == nil {
local = types.MakeLocalEnvironment(env)
node.Eval(local)
}
End:
responseToImporter <- importResponse{path: totalPath, env: local}
}
var directiveMutex sync.RWMutex
var directiveCache = map[string]types.NativeAppliable{}
func MakeImportDirective(basePath string) types.NativeAppliable {
return makeCheckedImportDirective(CheckPath(basePath))
}
// internal version where basePath must end with a "/"
func makeCheckedImportDirective(basePath string) types.NativeAppliable {
directiveMutex.RLock()
res, ok := directiveCache[basePath]
directiveMutex.RUnlock()
if !ok {
directiveMutex.Lock()
res, ok = directiveCache[basePath]
if !ok {
res = types.MakeNativeAppliable(func(env types.Environment, itArgs types.Iterator) types.Object {
arg0, _ := itArgs.Next()
filePath, ok := arg0.Eval(env).(types.String)
if ok {
response := make(chan types.Environment)
requestToImporter <- importRequest{
basePath: basePath, filePath: string(filePath), responder: response,
}
otherEnv := <-response
if otherEnv != nil {
otherEnv.CopyTo(env)
}
}
return types.None
})
directiveCache[basePath] = res
}
directiveMutex.Unlock()
}
return res
}
// add an ending "/" if necessary
func CheckPath(path string) string {
if path[len(path)-1] != '/' {
path += "/"
}
return path
}