mirror of
https://github.com/autc04/Retro68.git
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361 lines
9.6 KiB
Go
361 lines
9.6 KiB
Go
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package io_test
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import (
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"bytes"
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"crypto/sha1"
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"errors"
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"fmt"
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. "io"
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"io/ioutil"
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"runtime"
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"strings"
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"testing"
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"time"
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)
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func TestMultiReader(t *testing.T) {
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var mr Reader
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var buf []byte
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nread := 0
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withFooBar := func(tests func()) {
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r1 := strings.NewReader("foo ")
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r2 := strings.NewReader("")
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r3 := strings.NewReader("bar")
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mr = MultiReader(r1, r2, r3)
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buf = make([]byte, 20)
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tests()
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}
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expectRead := func(size int, expected string, eerr error) {
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nread++
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n, gerr := mr.Read(buf[0:size])
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if n != len(expected) {
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t.Errorf("#%d, expected %d bytes; got %d",
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nread, len(expected), n)
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}
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got := string(buf[0:n])
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if got != expected {
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t.Errorf("#%d, expected %q; got %q",
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nread, expected, got)
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}
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if gerr != eerr {
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t.Errorf("#%d, expected error %v; got %v",
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nread, eerr, gerr)
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}
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buf = buf[n:]
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}
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withFooBar(func() {
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expectRead(2, "fo", nil)
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expectRead(5, "o ", nil)
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expectRead(5, "bar", nil)
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expectRead(5, "", EOF)
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})
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withFooBar(func() {
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expectRead(4, "foo ", nil)
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expectRead(1, "b", nil)
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expectRead(3, "ar", nil)
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expectRead(1, "", EOF)
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})
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withFooBar(func() {
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expectRead(5, "foo ", nil)
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})
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}
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func TestMultiWriter(t *testing.T) {
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sink := new(bytes.Buffer)
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// Hide bytes.Buffer's WriteString method:
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testMultiWriter(t, struct {
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Writer
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fmt.Stringer
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}{sink, sink})
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}
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func TestMultiWriter_String(t *testing.T) {
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testMultiWriter(t, new(bytes.Buffer))
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}
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// test that a multiWriter.WriteString calls results in at most 1 allocation,
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// even if multiple targets don't support WriteString.
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func TestMultiWriter_WriteStringSingleAlloc(t *testing.T) {
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t.Skip("skipping on gccgo until we have escape analysis")
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var sink1, sink2 bytes.Buffer
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type simpleWriter struct { // hide bytes.Buffer's WriteString
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Writer
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}
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mw := MultiWriter(simpleWriter{&sink1}, simpleWriter{&sink2})
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allocs := int(testing.AllocsPerRun(1000, func() {
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WriteString(mw, "foo")
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}))
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if allocs != 1 {
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t.Errorf("num allocations = %d; want 1", allocs)
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}
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}
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type writeStringChecker struct{ called bool }
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func (c *writeStringChecker) WriteString(s string) (n int, err error) {
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c.called = true
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return len(s), nil
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}
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func (c *writeStringChecker) Write(p []byte) (n int, err error) {
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return len(p), nil
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}
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func TestMultiWriter_StringCheckCall(t *testing.T) {
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var c writeStringChecker
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mw := MultiWriter(&c)
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WriteString(mw, "foo")
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if !c.called {
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t.Error("did not see WriteString call to writeStringChecker")
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}
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}
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func testMultiWriter(t *testing.T, sink interface {
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Writer
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fmt.Stringer
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}) {
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sha1 := sha1.New()
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mw := MultiWriter(sha1, sink)
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sourceString := "My input text."
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source := strings.NewReader(sourceString)
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written, err := Copy(mw, source)
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if written != int64(len(sourceString)) {
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t.Errorf("short write of %d, not %d", written, len(sourceString))
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}
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if err != nil {
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t.Errorf("unexpected error: %v", err)
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}
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sha1hex := fmt.Sprintf("%x", sha1.Sum(nil))
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if sha1hex != "01cb303fa8c30a64123067c5aa6284ba7ec2d31b" {
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t.Error("incorrect sha1 value")
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}
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if sink.String() != sourceString {
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t.Errorf("expected %q; got %q", sourceString, sink.String())
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}
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}
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// writerFunc is an io.Writer implemented by the underlying func.
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type writerFunc func(p []byte) (int, error)
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func (f writerFunc) Write(p []byte) (int, error) {
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return f(p)
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}
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// Test that MultiWriter properly flattens chained multiWriters,
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func TestMultiWriterSingleChainFlatten(t *testing.T) {
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pc := make([]uintptr, 1000) // 1000 should fit the full stack
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n := runtime.Callers(0, pc)
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var myDepth = callDepth(pc[:n])
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var writeDepth int // will contain the depth from which writerFunc.Writer was called
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var w Writer = MultiWriter(writerFunc(func(p []byte) (int, error) {
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n := runtime.Callers(1, pc)
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writeDepth += callDepth(pc[:n])
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return 0, nil
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}))
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mw := w
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// chain a bunch of multiWriters
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for i := 0; i < 100; i++ {
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mw = MultiWriter(w)
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}
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mw = MultiWriter(w, mw, w, mw)
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mw.Write(nil) // don't care about errors, just want to check the call-depth for Write
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if writeDepth != 4*(myDepth+2) { // 2 should be multiWriter.Write and writerFunc.Write
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t.Errorf("multiWriter did not flatten chained multiWriters: expected writeDepth %d, got %d",
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4*(myDepth+2), writeDepth)
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}
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}
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func TestMultiWriterError(t *testing.T) {
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f1 := writerFunc(func(p []byte) (int, error) {
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return len(p) / 2, ErrShortWrite
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})
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f2 := writerFunc(func(p []byte) (int, error) {
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t.Errorf("MultiWriter called f2.Write")
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return len(p), nil
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})
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w := MultiWriter(f1, f2)
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n, err := w.Write(make([]byte, 100))
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if n != 50 || err != ErrShortWrite {
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t.Errorf("Write = %d, %v, want 50, ErrShortWrite", n, err)
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}
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}
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// Test that MultiReader copies the input slice and is insulated from future modification.
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func TestMultiReaderCopy(t *testing.T) {
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slice := []Reader{strings.NewReader("hello world")}
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r := MultiReader(slice...)
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slice[0] = nil
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data, err := ioutil.ReadAll(r)
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if err != nil || string(data) != "hello world" {
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t.Errorf("ReadAll() = %q, %v, want %q, nil", data, err, "hello world")
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}
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}
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// Test that MultiWriter copies the input slice and is insulated from future modification.
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func TestMultiWriterCopy(t *testing.T) {
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var buf bytes.Buffer
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slice := []Writer{&buf}
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w := MultiWriter(slice...)
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slice[0] = nil
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n, err := w.Write([]byte("hello world"))
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if err != nil || n != 11 {
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t.Errorf("Write(`hello world`) = %d, %v, want 11, nil", n, err)
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}
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if buf.String() != "hello world" {
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t.Errorf("buf.String() = %q, want %q", buf.String(), "hello world")
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}
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}
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// readerFunc is an io.Reader implemented by the underlying func.
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type readerFunc func(p []byte) (int, error)
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func (f readerFunc) Read(p []byte) (int, error) {
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return f(p)
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}
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// callDepth returns the logical call depth for the given PCs.
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func callDepth(callers []uintptr) (depth int) {
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frames := runtime.CallersFrames(callers)
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more := true
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for more {
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_, more = frames.Next()
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depth++
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}
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return
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}
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// Test that MultiReader properly flattens chained multiReaders when Read is called
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func TestMultiReaderFlatten(t *testing.T) {
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pc := make([]uintptr, 1000) // 1000 should fit the full stack
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n := runtime.Callers(0, pc)
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var myDepth = callDepth(pc[:n])
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var readDepth int // will contain the depth from which fakeReader.Read was called
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var r Reader = MultiReader(readerFunc(func(p []byte) (int, error) {
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n := runtime.Callers(1, pc)
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readDepth = callDepth(pc[:n])
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return 0, errors.New("irrelevant")
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}))
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// chain a bunch of multiReaders
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for i := 0; i < 100; i++ {
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r = MultiReader(r)
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}
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r.Read(nil) // don't care about errors, just want to check the call-depth for Read
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if readDepth != myDepth+2 { // 2 should be multiReader.Read and fakeReader.Read
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t.Errorf("multiReader did not flatten chained multiReaders: expected readDepth %d, got %d",
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myDepth+2, readDepth)
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}
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}
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// byteAndEOFReader is a Reader which reads one byte (the underlying
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// byte) and io.EOF at once in its Read call.
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type byteAndEOFReader byte
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func (b byteAndEOFReader) Read(p []byte) (n int, err error) {
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if len(p) == 0 {
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// Read(0 bytes) is useless. We expect no such useless
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// calls in this test.
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panic("unexpected call")
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}
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p[0] = byte(b)
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return 1, EOF
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}
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// This used to yield bytes forever; issue 16795.
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func TestMultiReaderSingleByteWithEOF(t *testing.T) {
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got, err := ioutil.ReadAll(LimitReader(MultiReader(byteAndEOFReader('a'), byteAndEOFReader('b')), 10))
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if err != nil {
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t.Fatal(err)
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}
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const want = "ab"
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if string(got) != want {
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t.Errorf("got %q; want %q", got, want)
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}
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}
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// Test that a reader returning (n, EOF) at the end of an MultiReader
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// chain continues to return EOF on its final read, rather than
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// yielding a (0, EOF).
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func TestMultiReaderFinalEOF(t *testing.T) {
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r := MultiReader(bytes.NewReader(nil), byteAndEOFReader('a'))
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buf := make([]byte, 2)
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n, err := r.Read(buf)
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if n != 1 || err != EOF {
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t.Errorf("got %v, %v; want 1, EOF", n, err)
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}
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}
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func TestMultiReaderFreesExhaustedReaders(t *testing.T) {
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if runtime.Compiler == "gccgo" {
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t.Skip("skipping finalizer test on gccgo with conservative GC")
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}
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var mr Reader
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closed := make(chan struct{})
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// The closure ensures that we don't have a live reference to buf1
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// on our stack after MultiReader is inlined (Issue 18819). This
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// is a work around for a limitation in liveness analysis.
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func() {
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buf1 := bytes.NewReader([]byte("foo"))
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buf2 := bytes.NewReader([]byte("bar"))
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mr = MultiReader(buf1, buf2)
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runtime.SetFinalizer(buf1, func(*bytes.Reader) {
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close(closed)
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})
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}()
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buf := make([]byte, 4)
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if n, err := ReadFull(mr, buf); err != nil || string(buf) != "foob" {
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t.Fatalf(`ReadFull = %d (%q), %v; want 3, "foo", nil`, n, buf[:n], err)
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}
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runtime.GC()
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select {
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case <-closed:
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case <-time.After(5 * time.Second):
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t.Fatal("timeout waiting for collection of buf1")
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}
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if n, err := ReadFull(mr, buf[:2]); err != nil || string(buf[:2]) != "ar" {
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t.Fatalf(`ReadFull = %d (%q), %v; want 2, "ar", nil`, n, buf[:n], err)
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}
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}
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func TestInterleavedMultiReader(t *testing.T) {
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r1 := strings.NewReader("123")
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r2 := strings.NewReader("45678")
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mr1 := MultiReader(r1, r2)
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mr2 := MultiReader(mr1)
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buf := make([]byte, 4)
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// Have mr2 use mr1's []Readers.
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// Consume r1 (and clear it for GC to handle) and consume part of r2.
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n, err := ReadFull(mr2, buf)
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if got := string(buf[:n]); got != "1234" || err != nil {
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t.Errorf(`ReadFull(mr2) = (%q, %v), want ("1234", nil)`, got, err)
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}
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// Consume the rest of r2 via mr1.
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// This should not panic even though mr2 cleared r1.
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n, err = ReadFull(mr1, buf)
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if got := string(buf[:n]); got != "5678" || err != nil {
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t.Errorf(`ReadFull(mr1) = (%q, %v), want ("5678", nil)`, got, err)
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}
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}
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