mirror of
https://github.com/mgechev/revive.git
synced 2024-12-12 10:44:59 +02:00
2a1838f501
* adds default config to enable all rules out of the box
213 lines
4.8 KiB
Go
213 lines
4.8 KiB
Go
package rule
|
|
|
|
import (
|
|
"fmt"
|
|
"go/ast"
|
|
"go/token"
|
|
"sync"
|
|
|
|
"github.com/mgechev/revive/lint"
|
|
"golang.org/x/tools/go/ast/astutil"
|
|
)
|
|
|
|
// CognitiveComplexityRule lints given else constructs.
|
|
type CognitiveComplexityRule struct {
|
|
maxComplexity int
|
|
sync.Mutex
|
|
}
|
|
|
|
const defaultMaxCognitiveComplexity = 7
|
|
|
|
func (r *CognitiveComplexityRule) configure(arguments lint.Arguments) {
|
|
r.Lock()
|
|
defer r.Unlock()
|
|
if r.maxComplexity == 0 {
|
|
|
|
if len(arguments) < 1 {
|
|
r.maxComplexity = defaultMaxCognitiveComplexity
|
|
return
|
|
}
|
|
|
|
complexity, ok := arguments[0].(int64)
|
|
if !ok {
|
|
panic(fmt.Sprintf("invalid argument type for cognitive-complexity, expected int64, got %T", arguments[0]))
|
|
}
|
|
r.maxComplexity = int(complexity)
|
|
}
|
|
}
|
|
|
|
// Apply applies the rule to given file.
|
|
func (r *CognitiveComplexityRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
|
|
r.configure(arguments)
|
|
|
|
var failures []lint.Failure
|
|
|
|
linter := cognitiveComplexityLinter{
|
|
file: file,
|
|
maxComplexity: r.maxComplexity,
|
|
onFailure: func(failure lint.Failure) {
|
|
failures = append(failures, failure)
|
|
},
|
|
}
|
|
|
|
linter.lintCognitiveComplexity()
|
|
|
|
return failures
|
|
}
|
|
|
|
// Name returns the rule name.
|
|
func (*CognitiveComplexityRule) Name() string {
|
|
return "cognitive-complexity"
|
|
}
|
|
|
|
type cognitiveComplexityLinter struct {
|
|
file *lint.File
|
|
maxComplexity int
|
|
onFailure func(lint.Failure)
|
|
}
|
|
|
|
func (w cognitiveComplexityLinter) lintCognitiveComplexity() {
|
|
f := w.file
|
|
for _, decl := range f.AST.Decls {
|
|
if fn, ok := decl.(*ast.FuncDecl); ok && fn.Body != nil {
|
|
v := cognitiveComplexityVisitor{}
|
|
c := v.subTreeComplexity(fn.Body)
|
|
if c > w.maxComplexity {
|
|
w.onFailure(lint.Failure{
|
|
Confidence: 1,
|
|
Category: "maintenance",
|
|
Failure: fmt.Sprintf("function %s has cognitive complexity %d (> max enabled %d)", funcName(fn), c, w.maxComplexity),
|
|
Node: fn,
|
|
})
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
type cognitiveComplexityVisitor struct {
|
|
complexity int
|
|
nestingLevel int
|
|
}
|
|
|
|
// subTreeComplexity calculates the cognitive complexity of an AST-subtree.
|
|
func (v cognitiveComplexityVisitor) subTreeComplexity(n ast.Node) int {
|
|
ast.Walk(&v, n)
|
|
return v.complexity
|
|
}
|
|
|
|
// Visit implements the ast.Visitor interface.
|
|
func (v *cognitiveComplexityVisitor) Visit(n ast.Node) ast.Visitor {
|
|
switch n := n.(type) {
|
|
case *ast.IfStmt:
|
|
targets := []ast.Node{n.Cond, n.Body, n.Else}
|
|
v.walk(1, targets...)
|
|
return nil
|
|
case *ast.ForStmt:
|
|
targets := []ast.Node{n.Cond, n.Body}
|
|
v.walk(1, targets...)
|
|
return nil
|
|
case *ast.RangeStmt:
|
|
v.walk(1, n.Body)
|
|
return nil
|
|
case *ast.SelectStmt:
|
|
v.walk(1, n.Body)
|
|
return nil
|
|
case *ast.SwitchStmt:
|
|
v.walk(1, n.Body)
|
|
return nil
|
|
case *ast.TypeSwitchStmt:
|
|
v.walk(1, n.Body)
|
|
return nil
|
|
case *ast.FuncLit:
|
|
v.walk(0, n.Body) // do not increment the complexity, just do the nesting
|
|
return nil
|
|
case *ast.BinaryExpr:
|
|
v.complexity += v.binExpComplexity(n)
|
|
return nil // skip visiting binexp sub-tree (already visited by binExpComplexity)
|
|
case *ast.BranchStmt:
|
|
if n.Label != nil {
|
|
v.complexity++
|
|
}
|
|
}
|
|
// TODO handle (at least) direct recursion
|
|
|
|
return v
|
|
}
|
|
|
|
func (v *cognitiveComplexityVisitor) walk(complexityIncrement int, targets ...ast.Node) {
|
|
v.complexity += complexityIncrement + v.nestingLevel
|
|
nesting := v.nestingLevel
|
|
v.nestingLevel++
|
|
|
|
for _, t := range targets {
|
|
if t == nil {
|
|
continue
|
|
}
|
|
|
|
ast.Walk(v, t)
|
|
}
|
|
|
|
v.nestingLevel = nesting
|
|
}
|
|
|
|
func (cognitiveComplexityVisitor) binExpComplexity(n *ast.BinaryExpr) int {
|
|
calculator := binExprComplexityCalculator{opsStack: []token.Token{}}
|
|
|
|
astutil.Apply(n, calculator.pre, calculator.post)
|
|
|
|
return calculator.complexity
|
|
}
|
|
|
|
type binExprComplexityCalculator struct {
|
|
complexity int
|
|
opsStack []token.Token // stack of bool operators
|
|
subexpStarted bool
|
|
}
|
|
|
|
func (becc *binExprComplexityCalculator) pre(c *astutil.Cursor) bool {
|
|
switch n := c.Node().(type) {
|
|
case *ast.BinaryExpr:
|
|
isBoolOp := n.Op == token.LAND || n.Op == token.LOR
|
|
if !isBoolOp {
|
|
break
|
|
}
|
|
|
|
ops := len(becc.opsStack)
|
|
// if
|
|
// is the first boolop in the expression OR
|
|
// is the first boolop inside a subexpression (...) OR
|
|
// is not the same to the previous one
|
|
// then
|
|
// increment complexity
|
|
if ops == 0 || becc.subexpStarted || n.Op != becc.opsStack[ops-1] {
|
|
becc.complexity++
|
|
becc.subexpStarted = false
|
|
}
|
|
|
|
becc.opsStack = append(becc.opsStack, n.Op)
|
|
case *ast.ParenExpr:
|
|
becc.subexpStarted = true
|
|
}
|
|
|
|
return true
|
|
}
|
|
|
|
func (becc *binExprComplexityCalculator) post(c *astutil.Cursor) bool {
|
|
switch n := c.Node().(type) {
|
|
case *ast.BinaryExpr:
|
|
isBoolOp := n.Op == token.LAND || n.Op == token.LOR
|
|
if !isBoolOp {
|
|
break
|
|
}
|
|
|
|
ops := len(becc.opsStack)
|
|
if ops > 0 {
|
|
becc.opsStack = becc.opsStack[:ops-1]
|
|
}
|
|
case *ast.ParenExpr:
|
|
becc.subexpStarted = false
|
|
}
|
|
|
|
return true
|
|
}
|