Feature/add hashing

fsql.go

@@ -13,7 +13,9 @@ import (
 const Version = "0.2.0"
 
 var q *query.Query
-var attrs = [4]string{"mode", "size", "time", "name"}
+
+//Should be noted that this slice, is temporaly related to the order of printing
+var attrs = [5]string{"mode", "size", "time", "hash", "name"}
 
 // output prints the result value for each SELECTed attribute. Order is based
 // on the order the attributes appear in attrs.

parser/attribute.go

@@ -10,6 +10,7 @@ import (
 var allAttributes = map[string]bool{
 	"mode": true,
 	"name": true,
+	"hash": true,
 	"size": true,
 	"time": true,
 }

transform/common.go

@@ -24,3 +24,11 @@ func upper(name string) interface{} {
 func lower(name string) interface{} {
 	return strings.ToLower(name)
 }
+
+func truncate(str string, n int) string {
+	if len(str) < n || n > len(str) {
+		return str
+	}
+
+	return str[0:n]
+}

transform/format.go

@@ -1,8 +1,13 @@
 package transform
 
 import (
+	"crypto"
+	_ "crypto/sha1" //Import SHA-1 hashing function
+	"encoding/hex"
 	"fmt"
+	"io/ioutil"
 	"os"
+	"strconv"
 	"strings"
 	"time"
 )
@@ -31,6 +36,14 @@ func Format(p *FormatParams) (val interface{}, err error) {
 		val, err = p.fullPath()
 	case "SHORTPATH":
 		val, err = p.shortPath()
+	case "SHA1":
+		var hash string
+		hash, err = p.hash(crypto.SHA1)
+		if err == nil && len(p.Args) > 0 && p.Args[0] != "" {
+			if n, err := strconv.Atoi(p.Args[0]); err == nil {
+				val = truncate(hash, n)
+			}
+		}
 	}
 
 	if err != nil {
@@ -109,6 +122,30 @@ func (p *FormatParams) shortPath() (interface{}, error) {
 	return p.Info.Name(), nil
 }
 
+func (p *FormatParams) hash(hasher crypto.SignerOpts) (string, error) {
+	return hash(p.Info, p.Path, hasher)
+}
+
+func hash(info os.FileInfo, path string, hasher crypto.SignerOpts) (string, error) {
+	if info.IsDir() {
+		return "----------------------------------------", nil
+	}
+
+	f, err := os.Open(path)
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+	b, err := ioutil.ReadAll(f)
+	if err != nil {
+		return "", err
+	}
+
+	h := hasher.HashFunc().New()
+	h.Write(b)
+	return hex.EncodeToString(h.Sum(nil)), nil
+}
+
 // DefaultFormatValue returns the default format value for the provided
 // attribute attr based on path and info.
 func DefaultFormatValue(attr, path string, info os.FileInfo) interface{} {
@@ -121,6 +158,12 @@ func DefaultFormatValue(attr, path string, info os.FileInfo) interface{} {
 		return info.Size()
 	case "time":
 		return info.ModTime().Format(time.Stamp)
+	case "hash":
+		v, err := hash(info, path, crypto.SHA1)
+		if err != nil {
+			panic(err.Error())
+		}
+		return truncate(v, 7)
 	}
 	return nil
 }