| // Copyright 2009 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // This file implements a simple printer performance benchmark: |
| // go test -bench=BenchmarkPrint |
| |
| package printer |
| |
| import ( |
| "bytes" |
| "go/ast" |
| "go/parser" |
| "io" |
| "io/ioutil" |
| "log" |
| "testing" |
| ) |
| |
| var testfile *ast.File |
| |
| func testprint(out io.Writer, file *ast.File) { |
| if err := (&Config{TabIndent | UseSpaces, 8, 0}).Fprint(out, fset, file); err != nil { |
| log.Fatalf("print error: %s", err) |
| } |
| } |
| |
| // cannot initialize in init because (printer) Fprint launches goroutines. |
| func initialize() { |
| const filename = "testdata/parser.go" |
| |
| src, err := ioutil.ReadFile(filename) |
| if err != nil { |
| log.Fatalf("%s", err) |
| } |
| |
| file, err := parser.ParseFile(fset, filename, src, parser.ParseComments) |
| if err != nil { |
| log.Fatalf("%s", err) |
| } |
| |
| var buf bytes.Buffer |
| testprint(&buf, file) |
| if !bytes.Equal(buf.Bytes(), src) { |
| log.Fatalf("print error: %s not idempotent", filename) |
| } |
| |
| testfile = file |
| } |
| |
| func BenchmarkPrint(b *testing.B) { |
| if testfile == nil { |
| initialize() |
| } |
| for i := 0; i < b.N; i++ { |
| testprint(ioutil.Discard, testfile) |
| } |
| } |