github.com/sashka/siva@v1.6.0/cmd/siva/siva.go (about)

     1  package main
     2  
     3  import (
     4  	"fmt"
     5  	"os"
     6  
     7  	"gopkg.in/src-d/go-siva.v1"
     8  
     9  	"github.com/jessevdk/go-flags"
    10  )
    11  
    12  func main() {
    13  	parser := flags.NewNamedParser("siva", flags.Default)
    14  	parser.AddCommand("pack", "Create a new archive containing the specified items.", "", &CmdPack{})
    15  	parser.AddCommand("unpack", "Extract to disk from the archive.", "", &CmdUnpack{})
    16  	parser.AddCommand("list", "List the items contained on a file.", "", &CmdList{})
    17  	parser.AddCommand("version", "Show the version information.", "", &CmdVersion{})
    18  
    19  	_, err := parser.Parse()
    20  	if err != nil {
    21  		if e, ok := err.(*flags.Error); ok && e.Type == flags.ErrCommandRequired {
    22  			parser.WriteHelp(os.Stdout)
    23  		}
    24  
    25  		os.Exit(1)
    26  	}
    27  }
    28  
    29  type cmd struct {
    30  	Verbose bool `short:"v" description:"Activates the verbose mode"`
    31  	Args    struct {
    32  		File string `positional-arg-name:"siva-file" required:"true" description:"siva file."`
    33  	} `positional-args:"yes"`
    34  
    35  	f  *os.File
    36  	fi os.FileInfo
    37  	r  siva.Reader
    38  	w  siva.Writer
    39  }
    40  
    41  func (c *cmd) validate() error {
    42  	if c.Args.File == "" {
    43  		return fmt.Errorf("Missing .siva file, please provide a valid one.")
    44  	}
    45  	return nil
    46  }
    47  
    48  func (c *cmd) buildReader() (err error) {
    49  	c.f, err = os.Open(c.Args.File)
    50  	if err != nil {
    51  		return fmt.Errorf("error opening file: %s", err)
    52  	}
    53  
    54  	c.r = siva.NewReader(c.f)
    55  	return nil
    56  }
    57  
    58  func (c *cmd) buildWriter(append bool) (err error) {
    59  	flags := os.O_WRONLY
    60  	if append {
    61  		flags |= os.O_APPEND
    62  	} else {
    63  		flags |= os.O_CREATE | os.O_TRUNC
    64  	}
    65  
    66  	c.f, err = os.OpenFile(c.Args.File, flags, 0666)
    67  	if err != nil {
    68  		return fmt.Errorf("error creating file: %s", err)
    69  	}
    70  
    71  	c.fi, err = c.f.Stat()
    72  	if err != nil {
    73  		_ = c.f.Close()
    74  		return err
    75  	}
    76  
    77  	c.w = siva.NewWriter(c.f)
    78  	return nil
    79  }
    80  
    81  func (c *cmd) println(a ...interface{}) {
    82  	if !c.Verbose {
    83  		return
    84  	}
    85  
    86  	fmt.Println(a...)
    87  }
    88  
    89  func (c *cmd) close() (err error) {
    90  	defer func() {
    91  		if errC := c.f.Close(); errC != nil && err == nil {
    92  			err = errC
    93  		}
    94  	}()
    95  
    96  	if c.w != nil {
    97  		if err = c.w.Close(); err != nil {
    98  			return
    99  		}
   100  	}
   101  
   102  	return
   103  }