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
|
package script
import (
"context"
"fmt"
"github.com/d5/tengo/compiler"
"github.com/d5/tengo/compiler/parser"
"github.com/d5/tengo/compiler/source"
"github.com/d5/tengo/objects"
"github.com/d5/tengo/runtime"
)
// Script can simplify compilation and execution of embedded scripts.
type Script struct {
variables map[string]*Variable
modules *objects.ModuleMap
input []byte
maxAllocs int64
maxConstObjects int
enableFileImport bool
}
// New creates a Script instance with an input script.
func New(input []byte) *Script {
return &Script{
variables: make(map[string]*Variable),
input: input,
maxAllocs: -1,
maxConstObjects: -1,
}
}
// Add adds a new variable or updates an existing variable to the script.
func (s *Script) Add(name string, value interface{}) error {
obj, err := objects.FromInterface(value)
if err != nil {
return err
}
s.variables[name] = &Variable{
name: name,
value: obj,
}
return nil
}
// Remove removes (undefines) an existing variable for the script.
// It returns false if the variable name is not defined.
func (s *Script) Remove(name string) bool {
if _, ok := s.variables[name]; !ok {
return false
}
delete(s.variables, name)
return true
}
// SetImports sets import modules.
func (s *Script) SetImports(modules *objects.ModuleMap) {
s.modules = modules
}
// SetMaxAllocs sets the maximum number of objects allocations during the run time.
// Compiled script will return runtime.ErrObjectAllocLimit error if it exceeds this limit.
func (s *Script) SetMaxAllocs(n int64) {
s.maxAllocs = n
}
// SetMaxConstObjects sets the maximum number of objects in the compiled constants.
func (s *Script) SetMaxConstObjects(n int) {
s.maxConstObjects = n
}
// EnableFileImport enables or disables module loading from local files.
// Local file modules are disabled by default.
func (s *Script) EnableFileImport(enable bool) {
s.enableFileImport = enable
}
// Compile compiles the script with all the defined variables, and, returns Compiled object.
func (s *Script) Compile() (*Compiled, error) {
symbolTable, globals, err := s.prepCompile()
if err != nil {
return nil, err
}
fileSet := source.NewFileSet()
srcFile := fileSet.AddFile("(main)", -1, len(s.input))
p := parser.NewParser(srcFile, s.input, nil)
file, err := p.ParseFile()
if err != nil {
return nil, err
}
c := compiler.NewCompiler(srcFile, symbolTable, nil, s.modules, nil)
c.EnableFileImport(s.enableFileImport)
if err := c.Compile(file); err != nil {
return nil, err
}
// reduce globals size
globals = globals[:symbolTable.MaxSymbols()+1]
// global symbol names to indexes
globalIndexes := make(map[string]int, len(globals))
for _, name := range symbolTable.Names() {
symbol, _, _ := symbolTable.Resolve(name)
if symbol.Scope == compiler.ScopeGlobal {
globalIndexes[name] = symbol.Index
}
}
// remove duplicates from constants
bytecode := c.Bytecode()
bytecode.RemoveDuplicates()
// check the constant objects limit
if s.maxConstObjects >= 0 {
cnt := bytecode.CountObjects()
if cnt > s.maxConstObjects {
return nil, fmt.Errorf("exceeding constant objects limit: %d", cnt)
}
}
return &Compiled{
globalIndexes: globalIndexes,
bytecode: bytecode,
globals: globals,
maxAllocs: s.maxAllocs,
}, nil
}
// Run compiles and runs the scripts.
// Use returned compiled object to access global variables.
func (s *Script) Run() (compiled *Compiled, err error) {
compiled, err = s.Compile()
if err != nil {
return
}
err = compiled.Run()
return
}
// RunContext is like Run but includes a context.
func (s *Script) RunContext(ctx context.Context) (compiled *Compiled, err error) {
compiled, err = s.Compile()
if err != nil {
return
}
err = compiled.RunContext(ctx)
return
}
func (s *Script) prepCompile() (symbolTable *compiler.SymbolTable, globals []objects.Object, err error) {
var names []string
for name := range s.variables {
names = append(names, name)
}
symbolTable = compiler.NewSymbolTable()
for idx, fn := range objects.Builtins {
symbolTable.DefineBuiltin(idx, fn.Name)
}
globals = make([]objects.Object, runtime.GlobalsSize)
for idx, name := range names {
symbol := symbolTable.Define(name)
if symbol.Index != idx {
panic(fmt.Errorf("wrong symbol index: %d != %d", idx, symbol.Index))
}
globals[symbol.Index] = s.variables[name].value
}
return
}
func (s *Script) copyVariables() map[string]*Variable {
vars := make(map[string]*Variable)
for n, v := range s.variables {
vars[n] = v
}
return vars
}
|
