mirror of
https://github.com/cwinfo/matterbridge.git
synced 2024-11-10 07:30:28 +00:00
186 lines
4.4 KiB
Go
186 lines
4.4 KiB
Go
package script
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import (
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"context"
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"fmt"
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"github.com/d5/tengo/compiler"
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"github.com/d5/tengo/compiler/parser"
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"github.com/d5/tengo/compiler/source"
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"github.com/d5/tengo/objects"
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"github.com/d5/tengo/runtime"
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)
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// Script can simplify compilation and execution of embedded scripts.
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type Script struct {
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variables map[string]*Variable
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modules *objects.ModuleMap
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input []byte
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maxAllocs int64
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maxConstObjects int
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enableFileImport bool
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}
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// New creates a Script instance with an input script.
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func New(input []byte) *Script {
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return &Script{
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variables: make(map[string]*Variable),
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input: input,
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maxAllocs: -1,
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maxConstObjects: -1,
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}
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}
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// Add adds a new variable or updates an existing variable to the script.
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func (s *Script) Add(name string, value interface{}) error {
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obj, err := objects.FromInterface(value)
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if err != nil {
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return err
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}
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s.variables[name] = &Variable{
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name: name,
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value: obj,
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}
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return nil
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}
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// Remove removes (undefines) an existing variable for the script.
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// It returns false if the variable name is not defined.
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func (s *Script) Remove(name string) bool {
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if _, ok := s.variables[name]; !ok {
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return false
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}
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delete(s.variables, name)
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return true
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}
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// SetImports sets import modules.
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func (s *Script) SetImports(modules *objects.ModuleMap) {
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s.modules = modules
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}
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// SetMaxAllocs sets the maximum number of objects allocations during the run time.
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// Compiled script will return runtime.ErrObjectAllocLimit error if it exceeds this limit.
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func (s *Script) SetMaxAllocs(n int64) {
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s.maxAllocs = n
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}
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// SetMaxConstObjects sets the maximum number of objects in the compiled constants.
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func (s *Script) SetMaxConstObjects(n int) {
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s.maxConstObjects = n
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}
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// EnableFileImport enables or disables module loading from local files.
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// Local file modules are disabled by default.
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func (s *Script) EnableFileImport(enable bool) {
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s.enableFileImport = enable
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}
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// Compile compiles the script with all the defined variables, and, returns Compiled object.
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func (s *Script) Compile() (*Compiled, error) {
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symbolTable, globals, err := s.prepCompile()
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if err != nil {
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return nil, err
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}
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fileSet := source.NewFileSet()
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srcFile := fileSet.AddFile("(main)", -1, len(s.input))
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p := parser.NewParser(srcFile, s.input, nil)
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file, err := p.ParseFile()
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if err != nil {
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return nil, err
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}
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c := compiler.NewCompiler(srcFile, symbolTable, nil, s.modules, nil)
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c.EnableFileImport(s.enableFileImport)
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if err := c.Compile(file); err != nil {
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return nil, err
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}
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// reduce globals size
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globals = globals[:symbolTable.MaxSymbols()+1]
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// global symbol names to indexes
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globalIndexes := make(map[string]int, len(globals))
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for _, name := range symbolTable.Names() {
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symbol, _, _ := symbolTable.Resolve(name)
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if symbol.Scope == compiler.ScopeGlobal {
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globalIndexes[name] = symbol.Index
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}
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}
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// remove duplicates from constants
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bytecode := c.Bytecode()
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bytecode.RemoveDuplicates()
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// check the constant objects limit
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if s.maxConstObjects >= 0 {
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cnt := bytecode.CountObjects()
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if cnt > s.maxConstObjects {
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return nil, fmt.Errorf("exceeding constant objects limit: %d", cnt)
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}
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}
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return &Compiled{
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globalIndexes: globalIndexes,
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bytecode: bytecode,
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globals: globals,
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maxAllocs: s.maxAllocs,
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}, nil
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}
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// Run compiles and runs the scripts.
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// Use returned compiled object to access global variables.
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func (s *Script) Run() (compiled *Compiled, err error) {
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compiled, err = s.Compile()
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if err != nil {
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return
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}
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err = compiled.Run()
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return
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}
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// RunContext is like Run but includes a context.
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func (s *Script) RunContext(ctx context.Context) (compiled *Compiled, err error) {
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compiled, err = s.Compile()
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if err != nil {
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return
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}
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err = compiled.RunContext(ctx)
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return
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}
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func (s *Script) prepCompile() (symbolTable *compiler.SymbolTable, globals []objects.Object, err error) {
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var names []string
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for name := range s.variables {
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names = append(names, name)
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}
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symbolTable = compiler.NewSymbolTable()
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for idx, fn := range objects.Builtins {
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symbolTable.DefineBuiltin(idx, fn.Name)
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}
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globals = make([]objects.Object, runtime.GlobalsSize)
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for idx, name := range names {
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symbol := symbolTable.Define(name)
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if symbol.Index != idx {
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panic(fmt.Errorf("wrong symbol index: %d != %d", idx, symbol.Index))
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}
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globals[symbol.Index] = s.variables[name].value
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}
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return
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}
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