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|
package gocapturedrefrace
import (
"bytes"
"fmt"
"go/ast"
"go/printer"
"go/token"
"go/types"
"golang.org/x/tools/go/analysis"
)
var Analyzer = &analysis.Analyzer{
Name: "gocapturedrefrace",
Doc: "reports captured references in goroutine closures",
Run: run,
}
func run(pass *analysis.Pass) (interface{}, error) {
for _, file := range pass.Files {
ast.Inspect(
file,
func(node ast.Node) bool {
goStmt, ok := node.(*ast.GoStmt)
if !ok {
return true
}
var printedNode bytes.Buffer
err := printer.Fprint(&printedNode, pass.Fset, goStmt)
if err != nil {
panic(err)
}
fmt.Printf("%#v\n", goStmt)
// TODO: How to get types.Func or {ast,types}.Scope of function literal?
funcIdent, ok := goStmt.Call.Fun.(*ast.Ident)
funcObj := pass.TypesInfo.ObjectOf(funcIdent)
if funcObj != nil {
theFunc, ok := funcObj.(*types.Func)
if ok {
fmt.Printf("func scope: %#v\n", theFunc.Scope())
} else {
fmt.Println("func scope: error")
}
} else {
fmt.Println("funcObj: error")
}
// TODO: Get func literal of go statement
// TODO: Get variables in func literal
funcLit, ok := goStmt.Call.Fun.(*ast.FuncLit)
if !ok {
return true
}
// scope := pass.TypesInfo.Scopes[funcLit]
scope := pass.TypesInfo.Scopes[goStmt]
fmt.Println("scope:", scope)
checkClosure(pass, funcLit)
return true
},
)
}
return nil, nil
}
func checkClosure(pass *analysis.Pass, funcLit *ast.FuncLit) {
formalParams := []*ast.Object{}
for _, field := range funcLit.Type.Params.List {
formalParams = append(formalParams, field.Names[0].Obj)
}
fmt.Printf("formalParams: %#v\n", formalParams)
// TODO: Ensure argument types are not references
// TODO: goStmt.Call.Args should also give us something like this.
// TODO: Build a list of variables created in the closure
assignments := assignmentsInFunc(pass, funcLit)
fmt.Printf("variable declarations: %#v\n", assignments)
// TODO: Use ast.GenDecl instead
// ast.Scope?
ast.Inspect(
funcLit,
func(node ast.Node) bool {
ident, ok := node.(*ast.Ident)
if !ok {
return true
}
if ident.Obj == nil {
return true
}
// TODO: Find out whether ident is a captured reference
// Maybe check if variable was not assigned or passed as an argument?
for _, param := range formalParams {
if ident.Obj == param {
return true
}
}
pass.Reportf(
ident.Pos(),
"variable found %q",
ident,
)
return true
},
)
}
func assignmentsInFunc(
pass *analysis.Pass,
funcLit *ast.FuncLit,
) []string {
assignments := []string{}
// ) []*ast.Object {
// assignments := []*ast.Object{}
ast.Inspect(
funcLit,
func(node ast.Node) bool {
// decl, ok := node.(*ast.GenDecl)
// if !ok {
// return true
// }
//
// fmt.Printf("decl: %#v\n", decl)
//
// if decl.Tok != token.VAR {
// return true
// }
//
// for _, spec := range decl.Specs {
// valueSpec, ok := spec.(*ast.ValueSpec)
// if !ok {
// return true
// }
//
// fmt.Printf("valueSpec: %#v\n", valueSpec)
//
// assignments = append(assignments, valueSpec.Names[0].Obj)
// }
// decl, ok := node.(*ast.DeclStmt)
// if !ok {
// return true
// }
//
// fmt.Printf("decl: %#v\n", decl)
ident, ok := node.(*ast.Ident)
if !ok {
return true
}
if ident.Obj == nil || ident.Obj.Decl == nil {
return true
}
assignment, ok := ident.Obj.Decl.(*ast.AssignStmt)
if !ok {
return true
}
// fmt.Printf("assignment: %#v\n", assignment.Tok)
if assignment.Tok == token.DEFINE {
fmt.Printf("assignment: %v is DEFINE\n", ident.Name)
} else if assignment.Tok == token.ASSIGN {
fmt.Printf("assignment: %v is ASSIGN\n", ident.Name)
} else {
fmt.Printf("assignment: %v\n", assignment.Tok)
}
if pass.TypesInfo.Defs[ident] != nil {
fmt.Println("DEFINE:", ident)
} else {
fmt.Println("ASSIGN:", ident)
}
obj := pass.TypesInfo.ObjectOf(ident)
if obj != nil {
fmt.Printf("obj: %#v\n", obj)
theVar, ok := obj.(*types.Var)
if !ok {
return true
}
fmt.Printf("obj origin: %#v\n", theVar.Origin())
fmt.Printf("obj parent: %#v\n", theVar.Parent())
}
assignments = append(assignments, ident.Name)
return true
},
)
return assignments
}
|
