complete homework 7

Author: kpechenenko

hw07_file_copying/.sync

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"io"
+	"os"
+)
+
+// filesHasSameContent содержат ли файлы идентичный контент в байтах?
+func filesHasSameContent(path1 string, path2 string) (bool, error) {
+	f1, err := os.Open(path1)
+	if err != nil {
+		return false, err
+	}
+	f2, err := os.Open(path2)
+	if err != nil {
+		return false, err
+	}
+	buf1, err := io.ReadAll(f1)
+	if err != nil {
+		return false, err
+	}
+	buf2, err := io.ReadAll(f2)
+	if err != nil {
+		return false, err
+	}
+	if len(buf1) != len(buf2) {
+		return false, nil
+	}
+	for i := 0; i < len(buf1); i++ {
+		if buf1[i] != buf2[i] {
+			return false, nil
+		}
+	}
+	return true, nil
+}

hw07_file_copying/compare.go

@@ -0,0 +1,69 @@
+package main
+
+import (
+	"github.com/stretchr/testify/assert"
+	"os"
+	"testing"
+)
+
+func TestFilesHasSameContent(t *testing.T) {
+	testCases := []struct {
+		name  string
+		path1 string
+		path2 string
+		same  bool
+		err   error
+	}{
+		{
+			name:  "1 file does not exist",
+			path1: "testdata/efjewofweofkewp;",
+			path2: "testdata/input.txt",
+			same:  false,
+			err:   os.ErrNotExist,
+		},
+		{
+			name:  "2 file does not exist",
+			path1: "testdata/input.txt",
+			path2: "testdata/dlwpdewpdlewpdpew",
+			same:  false,
+			err:   os.ErrNotExist,
+		},
+		{
+			name:  "same file",
+			path1: "testdata/input.txt",
+			path2: "testdata/input.txt",
+			same:  true,
+			err:   nil,
+		},
+		{
+			name:  "another same file",
+			path1: "testdata/out_offset0_limit0.txt",
+			path2: "testdata/out_offset0_limit0.txt",
+			same:  true,
+			err:   nil,
+		},
+		{
+			name:  "different files",
+			path1: "testdata/out_offset0_limit1000.txt",
+			path2: "testdata/input.txt",
+			same:  false,
+			err:   nil,
+		},
+		{
+			name:  "other different files",
+			path1: "testdata/out_offset100_limit1000.txt",
+			path2: "testdata/out_offset0_limit10000.txt",
+			same:  false,
+			err:   nil,
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			ok, err := filesHasSameContent(tc.path1, tc.path2)
+			if tc.err != nil {
+				assert.ErrorIs(t, err, tc.err)
+			}
+			assert.Equal(t, ok, tc.same)
+		})
+	}
+}

hw07_file_copying/compare_test.go

@@ -2,14 +2,64 @@ package main
 
 import (
 	"errors"
+	"github.com/cheggaaa/pb/v3"
+	"io"
+	"os"
 )
 
 var (
 	ErrUnsupportedFile       = errors.New("unsupported file")
 	ErrOffsetExceedsFileSize = errors.New("offset exceeds file size")
+	ErrNegativeOffset        = errors.New("offset is negative")
+	ErrNegativeLimit         = errors.New("limit is negative")
 )
 
+// Copy скопировать limit байтов из файла fromPath в файл toPath, начиная с offset байт.
 func Copy(fromPath, toPath string, offset, limit int64) error {
-	// Place your code here.
+	if offset < 0 {
+		return ErrNegativeOffset
+	}
+	if limit < 0 {
+		return ErrNegativeLimit
+	}
+	f, err := os.Open(fromPath)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	fInfo, err := f.Stat()
+	if err != nil {
+		return err
+	}
+	if offset > fInfo.Size() {
+		return ErrOffsetExceedsFileSize
+	}
+	if !fInfo.Mode().IsRegular() {
+		return ErrUnsupportedFile
+	}
+	// продвинуться внутри файла на offset байт, если необходимо
+	if offset > 0 {
+		_, err = f.Seek(offset, io.SeekStart)
+		if err != nil {
+			return err
+		}
+	}
+	newF, err := os.Create(toPath)
+	if err != nil {
+		return err
+	}
+	defer newF.Close()
+	// вычитать весь файл
+	if limit == 0 || limit > fInfo.Size()-offset {
+		limit = fInfo.Size() - offset
+	}
+	// прогресс бар в консоль
+	bar := pb.Full.Start64(limit)
+	proxyReader := bar.NewProxyReader(f)
+	_, err = io.CopyN(newF, proxyReader, limit)
+	if err != nil {
+		return err
+	}
+	bar.Finish()
 	return nil
 }

hw07_file_copying/copy.go

@@ -1,7 +1,134 @@
 package main
 
-import "testing"
+import (
+	"github.com/stretchr/testify/assert"
+	"os"
+	"testing"
+)
 
 func TestCopy(t *testing.T) {
-	// Place your code here.
+	testCases := []struct {
+		name          string
+		fromPath      string
+		toPath        string
+		validCopyPath string
+		offset        int64
+		limit         int64
+		err           error
+	}{
+		{
+			name:          "unsupported file",
+			fromPath:      "/dev/urandom",
+			toPath:        "/tmp/urandom.txt",
+			validCopyPath: "testdata/out_offset0_limit0.txt",
+			offset:        0,
+			limit:         0,
+			err:           ErrUnsupportedFile,
+		},
+		{
+			name:          "file from does not exist",
+			fromPath:      "testdata/ofkwe0fwepfkew",
+			toPath:        "/tmp/out_0_0.txt",
+			validCopyPath: "testdata/out_offset0_limit0.txt",
+			offset:        0,
+			limit:         0,
+			err:           os.ErrNotExist,
+		},
+		{
+			name:          "negative offset",
+			fromPath:      "testdata/input.txt",
+			toPath:        "/tmp/out_0_0.txt",
+			validCopyPath: "testdata/out_offset0_limit0.txt",
+			offset:        -1,
+			limit:         0,
+			err:           ErrNegativeOffset,
+		},
+		{
+			name:          "negative limit",
+			fromPath:      "testdata/input.txt",
+			toPath:        "/tmp/out_0_0.txt",
+			validCopyPath: "testdata/out_offset0_limit0.txt",
+			offset:        0,
+			limit:         -1,
+			err:           ErrNegativeLimit,
+		},
+		{
+			name:          "offset exceeds file size",
+			fromPath:      "testdata/input.txt",
+			toPath:        "/tmp/out_0_0.txt",
+			validCopyPath: "testdata/out_offset0_limit0.txt",
+			offset:        1_000_000_000,
+			limit:         0,
+			err:           ErrOffsetExceedsFileSize,
+		},
+		{
+			name:          "valid files offset 0 limit 0",
+			fromPath:      "testdata/input.txt",
+			toPath:        "/tmp/out_0_0.txt",
+			validCopyPath: "testdata/out_offset0_limit0.txt",
+			offset:        0,
+			limit:         0,
+			err:           nil,
+		},
+		{
+			name:          "valid files offset 0 limit 10",
+			fromPath:      "testdata/input.txt",
+			toPath:        "/tmp/out_0_10.txt",
+			validCopyPath: "testdata/out_offset0_limit10.txt",
+			offset:        0,
+			limit:         10,
+			err:           nil,
+		},
+		{
+			name:          "valid files offset 0 limit 1000",
+			fromPath:      "testdata/input.txt",
+			toPath:        "/tmp/out_0_1000.txt",
+			validCopyPath: "testdata/out_offset0_limit1000.txt",
+			offset:        0,
+			limit:         1000,
+			err:           nil,
+		},
+		{
+			name:          "valid files offset 0 limit 10000",
+			fromPath:      "testdata/input.txt",
+			toPath:        "/tmp/out_0_10000.txt",
+			validCopyPath: "testdata/out_offset0_limit10000.txt",
+			offset:        0,
+			limit:         10000,
+			err:           nil,
+		},
+		{
+			name:          "valid files offset 100 limit 1000",
+			fromPath:      "testdata/input.txt",
+			toPath:        "/tmp/out_100_1000.txt",
+			validCopyPath: "testdata/out_offset100_limit1000.txt",
+			offset:        100,
+			limit:         1000,
+			err:           nil,
+		},
+		{
+			name:          "valid files offset 6000 limit 1000",
+			fromPath:      "testdata/input.txt",
+			toPath:        "/tmp/out_6000_1000.txt",
+			validCopyPath: "testdata/out_offset6000_limit1000.txt",
+			offset:        6000,
+			limit:         1000,
+			err:           nil,
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			defer os.Remove(tc.toPath)
+			assert.FileExists(t, tc.validCopyPath)
+			err := Copy(tc.fromPath, tc.toPath, tc.offset, tc.limit)
+			if tc.err != nil {
+				assert.ErrorIs(t, err, tc.err)
+				return
+			}
+			assert.FileExists(t, tc.toPath)
+			ok, err := filesHasSameContent(tc.toPath, tc.validCopyPath)
+			assert.NoError(t, err)
+			assert.True(t, ok)
+		})
+	}
 }

hw07_file_copying/copy_test.go

@@ -1,3 +1,21 @@
 module github.com/kpechenenko/hw07_file_copying
 
 go 1.19
+
+require (
+	github.com/cheggaaa/pb/v3 v3.1.5
+	github.com/stretchr/testify v1.9.0
+)
+
+require (
+	github.com/VividCortex/ewma v1.2.0 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/fatih/color v1.15.0 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.19 // indirect
+	github.com/mattn/go-runewidth v0.0.15 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/rivo/uniseg v0.2.0 // indirect
+	golang.org/x/sys v0.6.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

hw07_file_copying/go.mod

@@ -0,0 +1,28 @@
+github.com/VividCortex/ewma v1.2.0 h1:f58SaIzcDXrSy3kWaHNvuJgJ3Nmz59Zji6XoJR/q1ow=
+github.com/VividCortex/ewma v1.2.0/go.mod h1:nz4BbCtbLyFDeC9SUHbtcT5644juEuWfUAUnGx7j5l4=
+github.com/cheggaaa/pb/v3 v3.1.5 h1:QuuUzeM2WsAqG2gMqtzaWithDJv0i+i6UlnwSCI4QLk=
+github.com/cheggaaa/pb/v3 v3.1.5/go.mod h1:CrxkeghYTXi1lQBEI7jSn+3svI3cuc19haAj6jM60XI=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/fatih/color v1.15.0 h1:kOqh6YHBtK8aywxGerMG2Eq3H6Qgoqeo13Bk2Mv/nBs=
+github.com/fatih/color v1.15.0/go.mod h1:0h5ZqXfHYED7Bhv2ZJamyIOUej9KtShiJESRwBDUSsw=
+github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
+github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
+github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
+github.com/mattn/go-isatty v0.0.19 h1:JITubQf0MOLdlGRuRq+jtsDlekdYPia9ZFsB8h/APPA=
+github.com/mattn/go-isatty v0.0.19/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/mattn/go-runewidth v0.0.15 h1:UNAjwbU9l54TA3KzvqLGxwWjHmMgBUVhBiTjelZgg3U=
+github.com/mattn/go-runewidth v0.0.15/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/rivo/uniseg v0.2.0 h1:S1pD9weZBuJdFmowNwbpi7BJ8TNftyUImj/0WQi72jY=
+github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
+github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
+github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0 h1:MVltZSvRTcU2ljQOhs94SXPftV6DCNnZViHeQps87pQ=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

hw07_file_copying/go.sum

@@ -2,6 +2,8 @@ package main
 
 import (
 	"flag"
+	"log"
+	"os"
 )
 
 var (
@@ -18,5 +20,10 @@ func init() {
 
 func main() {
 	flag.Parse()
-	// Place your code here.
+	flag.Parse()
+	err := Copy(from, to, offset, limit)
+	if err != nil {
+		log.Printf("copying file %s to %s failed: %v", from, to, err)
+		os.Exit(1)
+	}
 }