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Add flag parsing and input validation methods #18

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merged 1 commit into from
Mar 30, 2024
Merged

Add flag parsing and input validation methods #18

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107 changes: 65 additions & 42 deletions cli/cli.go
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Original file line number Diff line number Diff line change
Expand Up @@ -31,54 +31,32 @@ func (i *rawStrings) Set(value string) error {
type CLI struct {
outStream, errStream io.Writer
inputStream io.Reader

filePath string
replaceExpr string
isOverwrite bool
filters rawStrings
}

func NewCLI(outStream, errStream io.Writer, inputStream io.Reader) *CLI {
return &CLI{outStream: outStream, errStream: errStream, inputStream: inputStream}
}

func (c *CLI) Run(args []string) int {
flags := flag.NewFlagSet("purl", flag.ContinueOnError)
flags.SetOutput(c.errStream)

var replaceExpr string
var isOverwrite bool
var filters rawStrings

flags.BoolVar(&isOverwrite, "overwrite", false, "overwrite the file in place")
flags.StringVar(&replaceExpr, "replace", "", `Replacement expression, e.g., "@search@replace@"`)
flags.Var(&filters, "filter", `Filter expression`)

err := flags.Parse(args[1:])
flags, err := c.parseFlags(args)
if err != nil {
fmt.Fprintf(c.errStream, "Failed to parse flags: %s\n", err)
return ExitCodeParseFlagError
}

filePath := ""
if flags.NArg() > 0 {
filePath = flags.Arg(0)
} else if term.IsTerminal(int(os.Stdin.Fd())) {
fmt.Fprintln(c.errStream, "No input file specified")
return ExitCodeFail
}

if isOverwrite && filePath == "" {
fmt.Fprintln(c.errStream, "Cannot use -overwrite option with stdin")
return ExitCodeFail
}

if len(replaceExpr) != 0 && len(filters) != 0 {
fmt.Fprintln(c.errStream, "Cannot use -replace and -filter options together")
return ExitCodeFail
}

if len(filters) == 0 && len(replaceExpr) < 3 {
fmt.Fprintln(c.errStream, "Invalid replace expression format. Use \"@search@replace@\"")
err = c.validateInput(flags)
if err != nil {
fmt.Fprintf(c.errStream, "Failed to validate input: %s\n", err)
return ExitCodeFail
}

if filePath != "" {
file, err := os.Open(filePath)
if c.filePath != "" {
file, err := os.Open(c.filePath)
if err != nil {
fmt.Fprintf(c.errStream, "Failed to open file: %s\n", err)
return ExitCodeFail
Expand All @@ -90,7 +68,7 @@ func (c *CLI) Run(args []string) int {

var tmpFile *os.File

if isOverwrite {
if c.isOverwrite {
tmpFile, err = os.CreateTemp("", "purl")
if err != nil {
fmt.Fprintf(c.errStream, "Failed to create temp file: %s\n", err)
Expand All @@ -106,9 +84,9 @@ func (c *CLI) Run(args []string) int {
}
}

if len(replaceExpr) != 0 {
delimiter := string(replaceExpr[0])
parts := regexp.MustCompile(regexp.QuoteMeta(delimiter)).Split(replaceExpr[1:], -1)
if len(c.replaceExpr) > 0 {
delimiter := string(c.replaceExpr[0])
parts := regexp.MustCompile(regexp.QuoteMeta(delimiter)).Split(c.replaceExpr[1:], -1)
if len(parts) < 2 {
fmt.Fprintln(c.errStream, "Invalid replace expression format. Use \"@search@replace@\"")
return ExitCodeFail
Expand All @@ -121,8 +99,8 @@ func (c *CLI) Run(args []string) int {
}
}

if len(filters) != 0 {
regexps, err := compileRegexps(filters)
if len(c.filters) > 0 {
regexps, err := compileRegexps(c.filters)
if err != nil {
fmt.Fprintf(c.errStream, "Failed to compile regex patterns: %s\n", err)
return ExitCodeFail
Expand All @@ -135,8 +113,8 @@ func (c *CLI) Run(args []string) int {
}
}

if isOverwrite {
if err := os.Rename(tmpFile.Name(), filePath); err != nil {
if c.isOverwrite {
if err := os.Rename(tmpFile.Name(), c.filePath); err != nil {
fmt.Fprintf(c.errStream, "Failed to overwrite the original file: %s\n", err)
return ExitCodeFail
}
Expand All @@ -145,6 +123,51 @@ func (c *CLI) Run(args []string) int {
return ExitCodeOK
}

func (c *CLI) parseFlags(args []string) (*flag.FlagSet, error) {
flags := flag.NewFlagSet("purl", flag.ContinueOnError)
flags.SetOutput(c.errStream)

flags.BoolVar(&c.isOverwrite, "overwrite", false, "overwrite the file in place")
flags.StringVar(&c.replaceExpr, "replace", "", `Replacement expression, e.g., "@search@replace@"`)
flags.Var(&c.filters, "filter", `Filter expression`)

err := flags.Parse(args[1:])
if err != nil {
return nil, fmt.Errorf("failed to parse flags: %w", err)
}

return flags, nil
}

func (c *CLI) validateInput(flags *flag.FlagSet) error {
if flags.NArg() == 0 && term.IsTerminal(int(os.Stdin.Fd())) {
return fmt.Errorf("no input file specified")
}

if flags.NArg() == 0 && c.isOverwrite {
return fmt.Errorf("cannot use -overwrite option with stdin")
}

if len(c.replaceExpr) != 0 && len(c.filters) != 0 {
return fmt.Errorf("cannot use -replace and -filter options together")
}

if len(c.filters) == 0 && len(c.replaceExpr) < 3 {
return fmt.Errorf("invalid replace expression format. Use \"@search@replace@\"")
}

if flags.NArg() == 0 {
return nil
}

c.filePath = flags.Arg(0)
if _, err := os.Stat(c.filePath); os.IsNotExist(err) {
return fmt.Errorf("input file does not exist")
}

return nil
}

func (c *CLI) replaceProcess(searchPattern, replacement string) error {
scanner := bufio.NewScanner(c.inputStream)

Expand Down
41 changes: 36 additions & 5 deletions cli/cli_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -61,12 +61,43 @@ func TestRun_success(t *testing.T) {
}

func TestRun_failToProvideStdin(t *testing.T) {
outStream, errStream := new(bytes.Buffer), new(bytes.Buffer)
cl := cli.NewCLI(outStream, errStream, os.Stdin)
testCases := []struct {
desc string
args []string
expectedCode int
}{
{
desc: "fail to provide -replace",
args: []string{"purl", "-replace", "search@replacement"},
expectedCode: 1,
},
{
desc: "fail to provide -filter and -replace",
args: []string{"purl", "-filter", "aaa", "-replace", "@search@replacement@"},
expectedCode: 1,
},
{
desc: "non-existent file with -replace",
args: []string{"purl", "-replace", "@search@replacement@", "testdata/noexist.txt"},
expectedCode: 1,
},
{
desc: "non-existent file with -filter",
args: []string{"purl", "-filter", "aaaaa", "testdata/noexist.txt"},
expectedCode: 1,
},
}

expectedCode := 1
if got, expected := cl.Run([]string{"purl", "-replace", "@search@replacement@"}), expectedCode; got == expected {
t.Fatalf("Expected exit code %d, but got %d; error: %q", expected, got, errStream.String())
for _, tc := range testCases {
t.Run(tc.desc, func(t *testing.T) {
t.Parallel()
outStream, errStream := new(bytes.Buffer), new(bytes.Buffer)
cl := cli.NewCLI(outStream, errStream, os.Stdin)

if got := cl.Run(tc.args); got != tc.expectedCode {
t.Fatalf("Expected exit code %d, but got %d; error: %q", tc.expectedCode, got, errStream.String())
}
})
}
}

Expand Down