Use goroutines

formatter/cli_formatter.go

@@ -33,16 +33,17 @@ func formatFailure(failure linter.Failure) []string {
 }
 
 // Format formats the failures gotten from the linter.
-func (f *CLIFormatter) Format(failures []linter.Failure) (string, error) {
+func (f *CLIFormatter) Format(failures <-chan linter.Failure) (string, error) {
 	var result [][]string
 	var totalErrors = 0
-	for _, f := range failures {
+	var total = 0
+	for f := range failures {
 		result = append(result, formatFailure(f))
+		total++
 		if f.Type == linter.FailureTypeError {
 			totalErrors++
 		}
 	}
-	total := len(failures)
 	ps := "problems"
 	if total == 1 {
 		ps = "problem"

formatter/json_formatter.go

@@ -13,7 +13,7 @@ type JSONFormatter struct {
 }
 
 // Format formats the failures gotten from the linter.
-func (f *JSONFormatter) Format(failures []linter.Failure) (string, error) {
+func (f *JSONFormatter) Format(failures <-chan linter.Failure) (string, error) {
 	result, error := json.Marshal(failures)
 	if error != nil {
 		return "", error

linter/file.go

@@ -84,8 +84,7 @@ func (f *File) isMain() bool {
 	return false
 }
 
-func (f *File) lint(rules []Rule, rulesConfig RulesConfig) []Failure {
+func (f *File) lint(rules []Rule, rulesConfig RulesConfig, failures chan Failure) {
-	var failures []Failure
 	disabledIntervals := f.disabledIntervals(rules)
 	for _, currentRule := range rules {
 		config := rulesConfig[currentRule.Name()]
@@ -100,9 +99,10 @@ func (f *File) lint(rules []Rule, rulesConfig RulesConfig) []Failure {
 			currentFailures[idx] = failure
 		}
 		currentFailures = f.filterFailures(currentFailures, disabledIntervals)
-		failures = append(failures, currentFailures...)
+		for _, failure := range currentFailures {
+			failures <- failure
+		}
 	}
-	return failures
 }
 
 type enableDisableConfig struct {

linter/formatter.go

@@ -9,5 +9,5 @@ type FormatterMetadata struct {
 
 // Formatter defines an interface for failure formatters
 type Formatter interface {
-	Format([]Failure) string
+	Format(<-chan Failure) string
 }

linter/linter.go

@@ -42,7 +42,8 @@ func isGenerated(src []byte) bool {
 }
 
 // Lint lints a set of files with the specified rule.
-func (l *Linter) Lint(filenames []string, ruleSet []Rule, rulesConfig RulesConfig) ([]Failure, error) {
+func (l *Linter) Lint(filenames []string, ruleSet []Rule, rulesConfig RulesConfig) (<-chan Failure, error) {
+	failures := make(chan Failure)
 	pkg := &Package{
 		fset:  token.NewFileSet(),
 		files: map[string]*File{},
@@ -71,5 +72,9 @@ func (l *Linter) Lint(filenames []string, ruleSet []Rule, rulesConfig RulesConfi
 		pkg.files[filename] = file
 	}
 
-	return pkg.lint(ruleSet, rulesConfig), nil
+	go (func() {
+		pkg.lint(ruleSet, rulesConfig, failures)
+	})()
+
+	return failures, nil
 }

linter/package.go

@@ -4,6 +4,7 @@ import (
 	"go/ast"
 	"go/token"
 	"go/types"
+	"sync"
 
 	"golang.org/x/tools/go/gcexportdata"
 )
@@ -84,11 +85,16 @@ func (p *Package) TypeOf(expr ast.Expr) types.Type {
 	return p.TypesInfo.TypeOf(expr)
 }
 
-func (p *Package) lint(rules []Rule, config RulesConfig) []Failure {
+func (p *Package) lint(rules []Rule, config RulesConfig, failures chan Failure) {
-	var failures []Failure
 	p.TypeCheck()
+	var wg sync.WaitGroup
 	for _, file := range p.files {
-		failures = append(failures, file.lint(rules, config)...)
+		wg.Add(1)
+		go (func(file *File) {
+			file.lint(rules, config, failures)
+			defer wg.Done()
+		})(file)
 	}
-	return failures
+	wg.Wait()
+	close(failures)
 }