/
generator.go
222 lines (183 loc) · 4.83 KB
/
generator.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
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
package fsm
import (
"bytes"
"encoding/json"
"errors"
"fmt"
"go/constant"
"go/types"
"io"
"os"
"path/filepath"
"strconv"
"strings"
"text/template"
"golang.org/x/tools/go/packages"
"golang.org/x/tools/imports"
"gopkg.in/yaml.v2"
"moul.io/graphman/viz"
)
// Options for NewGenerator constructor
type Options struct {
// InputPackage is an import path or a relative path of the package that contains the source struct
InputPackage string
// OutputFile name for output file
OutputFile string
// Struct is name of struct
Struct string
// StateField is name of struct field that indicate state
StateField string
// TransitionsFile is path to file which hold supported transitions
TransitionsFile string
// DisableGoGenerate don't put go generate
DisableGoGenerate bool
// ActionGraphOutputFile path to action graph file
ActionGraphOutputFile string
}
// Generator generates finite state machine
type Generator struct {
Options
struc Struct
srcPackage *packages.Package
fsmTemplate *template.Template
}
// NewGenerator returns a pointer to Generator
func NewGenerator(opt Options) (*Generator, error) {
cfg := &packages.Config{
Mode: packages.NeedName | packages.NeedFiles | packages.NeedCompiledGoFiles | packages.NeedImports | packages.NeedTypes | packages.NeedTypesSizes | packages.NeedSyntax | packages.NeedTypesInfo,
Dir: filepath.Dir(opt.InputPackage),
}
pkgs, err := packages.Load(cfg, opt.InputPackage)
if err != nil {
return nil, err
}
if len(pkgs) != 1 {
return nil, fmt.Errorf("error: %d packages found", len(pkgs))
}
funcs := map[string]interface{}{
"to_camel": ToCamelCase,
"join": strings.Join,
"rel": filepath.Rel,
"dir": filepath.Dir,
"base": filepath.Base,
"path_join": filepath.Join,
}
tpl, err := template.New("fsm").Funcs(funcs).Parse(fsmTemplate)
if err != nil {
return nil, fmt.Errorf("failed to parse template: %w", err)
}
gen := &Generator{
Options: opt,
srcPackage: pkgs[0],
fsmTemplate: tpl,
}
if err := gen.fillStruct(); err != nil {
return nil, err
}
if opt.TransitionsFile != "" {
decoder := json.Unmarshal
ext := filepath.Ext(opt.TransitionsFile)
if ext == ".yaml" || ext == ".yml" {
decoder = yaml.Unmarshal
}
data, err := os.ReadFile(opt.TransitionsFile)
if err != nil {
return nil, fmt.Errorf("failed to read transitions file: %w", err)
}
if err := decoder(data, &gen.struc.Transitions); err != nil {
return nil, fmt.Errorf("failed to unmarshal transitions file: %w", err)
}
}
if err := gen.struc.Validate(); err != nil {
return nil, err
}
return gen, nil
}
// fillStruct find info about struct and state values for generator
func (g *Generator) fillStruct() error {
g.struc = Struct{
Name: g.Struct,
StateField: g.StateField,
StateValues: make([]StateValue, 0, 10),
}
for _, def := range g.srcPackage.TypesInfo.Defs {
typ, ok := def.(*types.TypeName)
if !ok {
continue
}
if def.Name() != g.Struct {
continue
}
st, ok := typ.Type().Underlying().(*types.Struct)
if !ok {
return fmt.Errorf("%s is not struct", g.Struct)
}
for i := 0; i < st.NumFields(); i++ {
if f := st.Field(i); f.Name() == g.StateField {
typ, ok := f.Type().(*types.Named)
if !ok {
return fmt.Errorf("%s.%s is not enum", def.Name(), f.Name())
}
g.struc.StateType = typ.Obj().Name()
break
}
}
// we found needed struct so no need to loop anymore
break
}
// find values for field type
for _, def := range g.srcPackage.TypesInfo.Defs {
val, ok := def.(*types.Const)
if !ok {
continue
}
typ, ok := val.Type().(*types.Named)
if !ok {
continue
}
if typ.Obj().Name() != g.struc.StateType {
continue
}
if val.Name() == "_" {
continue
}
valStr := val.Val().String()
if val.Val().Kind() == constant.String {
valStr, _ = strconv.Unquote(valStr)
}
g.struc.StateValues = append(g.struc.StateValues, StateValue{
Name: val.Name(),
Val: valStr,
})
}
return nil
}
// Generate generates code using template
func (g *Generator) Generate(w io.Writer) error {
buf := bytes.NewBuffer([]byte{})
if err := g.fsmTemplate.Execute(buf, map[string]interface{}{
"Struct": g.struc,
"Transitions": g.struc.Transitions,
"Package": g.srcPackage,
"Options": g.Options,
}); err != nil {
return err
}
processedSource, err := imports.Process(g.Options.OutputFile, buf.Bytes(), nil)
if err != nil {
return fmt.Errorf("failed to format generated code: %w", err)
}
_, err = w.Write(processedSource)
return err
}
func (g *Generator) GenerateTransitionGraph(w io.Writer) error {
if len(g.struc.Transitions) == 0 {
return errors.New("for generating graph transitions is required")
}
graph, err := viz.ToGraphviz(g.struc.Transitions.Graph(), nil)
if err != nil {
return err
}
_, err = w.Write([]byte(graph))
return err
}