forked from mgechev/revive
/
function-length.go
177 lines (150 loc) 路 4.25 KB
/
function-length.go
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package rule
import (
"fmt"
"go/ast"
"reflect"
"sync"
"github.com/mgechev/revive/lint"
)
// FunctionLength lint.
type FunctionLength struct {
maxStmt int
maxLines int
configured bool
sync.Mutex
}
func (r *FunctionLength) configure(arguments lint.Arguments) {
r.Lock()
r.Unlock()
if !r.configured {
maxStmt, maxLines := r.parseArguments(arguments)
r.maxStmt = int(maxStmt)
r.maxLines = int(maxLines)
r.configured = true
}
}
// Apply applies the rule to given file.
func (r *FunctionLength) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
r.configure(arguments)
var failures []lint.Failure
walker := lintFuncLength{
file: file,
maxStmt: r.maxStmt,
maxLines: r.maxLines,
onFailure: func(failure lint.Failure) {
failures = append(failures, failure)
},
}
ast.Walk(walker, file.AST)
return failures
}
// Name returns the rule name.
func (*FunctionLength) Name() string {
return "function-length"
}
const defaultFuncStmtsLimit = 50
const defaultFuncLinesLimit = 75
func (*FunctionLength) parseArguments(arguments lint.Arguments) (maxStmt, maxLines int64) {
if len(arguments) == 0 {
return defaultFuncStmtsLimit, defaultFuncLinesLimit
}
if len(arguments) != 2 {
panic(fmt.Sprintf(`invalid configuration for "function-length" rule, expected 2 arguments but got %d`, len(arguments)))
}
maxStmt, maxStmtOk := arguments[0].(int64)
if !maxStmtOk {
panic(fmt.Sprintf(`invalid configuration value for max statements in "function-length" rule; need int64 but got %T`, arguments[0]))
}
if maxStmt < 0 {
panic(fmt.Sprintf(`the configuration value for max statements in "function-length" rule cannot be negative, got %d`, maxStmt))
}
maxLines, maxLinesOk := arguments[1].(int64)
if !maxLinesOk {
panic(fmt.Sprintf(`invalid configuration value for max lines in "function-length" rule; need int64 but got %T`, arguments[1]))
}
if maxLines < 0 {
panic(fmt.Sprintf(`the configuration value for max statements in "function-length" rule cannot be negative, got %d`, maxLines))
}
return maxStmt, maxLines
}
type lintFuncLength struct {
file *lint.File
maxStmt int
maxLines int
onFailure func(lint.Failure)
}
func (w lintFuncLength) Visit(n ast.Node) ast.Visitor {
node, ok := n.(*ast.FuncDecl)
if !ok {
return w
}
body := node.Body
if body == nil || len(node.Body.List) == 0 {
return nil
}
if w.maxStmt > 0 {
stmtCount := w.countStmts(node.Body.List)
if stmtCount > w.maxStmt {
w.onFailure(lint.Failure{
Confidence: 1,
Failure: fmt.Sprintf("maximum number of statements per function exceeded; max %d but got %d", w.maxStmt, stmtCount),
Node: node,
})
}
}
if w.maxLines > 0 {
lineCount := w.countLines(node.Body)
if lineCount > w.maxLines {
w.onFailure(lint.Failure{
Confidence: 1,
Failure: fmt.Sprintf("maximum number of lines per function exceeded; max %d but got %d", w.maxLines, lineCount),
Node: node,
})
}
}
return nil
}
func (w lintFuncLength) countLines(b *ast.BlockStmt) int {
return w.file.ToPosition(b.End()).Line - w.file.ToPosition(b.Pos()).Line - 1
}
func (w lintFuncLength) countStmts(b []ast.Stmt) int {
count := 0
for _, s := range b {
switch stmt := s.(type) {
case *ast.BlockStmt:
count += w.countStmts(stmt.List)
case *ast.IfStmt:
count += 1 + w.countBodyListStmts(stmt)
if stmt.Else != nil {
elseBody, ok := stmt.Else.(*ast.BlockStmt)
if ok {
count += w.countStmts(elseBody.List)
}
}
case *ast.ForStmt, *ast.RangeStmt,
*ast.SwitchStmt, *ast.TypeSwitchStmt, *ast.SelectStmt:
count += 1 + w.countBodyListStmts(stmt)
case *ast.CaseClause:
count += w.countStmts(stmt.Body)
case *ast.AssignStmt:
count += 1 + w.countFuncLitStmts(stmt.Rhs[0])
case *ast.GoStmt:
count += 1 + w.countFuncLitStmts(stmt.Call.Fun)
case *ast.DeferStmt:
count += 1 + w.countFuncLitStmts(stmt.Call.Fun)
default:
count++
}
}
return count
}
func (w lintFuncLength) countFuncLitStmts(stmt ast.Expr) int {
if block, ok := stmt.(*ast.FuncLit); ok {
return w.countStmts(block.Body.List)
}
return 0
}
func (w lintFuncLength) countBodyListStmts(t interface{}) int {
i := reflect.ValueOf(t).Elem().FieldByName(`Body`).Elem().FieldByName(`List`).Interface()
return w.countStmts(i.([]ast.Stmt))
}