Subversion Repositories openrisc

// 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:
// gotest -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}).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)
        }
}