Add pool for sha1 hasher in MySQL

.gitignore

@@ -20,3 +20,6 @@ _testmain.go
 
 # Cloud 9
 .c9revisions/
+
+# Sublime
+*.sublime-workspace

Mysql.go → MySQL.go

@@ -1,19 +1,26 @@
 package passwords
 
 import (
-	"crypto/sha1"
 	"encoding/hex"
+	"hash"
 )
 
 // Passwords for MySql
 func MySQL(pass string) string {
-	// Create our own hasher, for thread safety
-	hasher := sha1.New()
+	// Get our own hasher, for thread safety
+	hasher := sha1Pool.Get().(hash.Hash)
+	// Back to the pool! (later)
+	defer sha1Pool.Put(hasher)
+
+	// We cannot assume the hasher from the pool is clean
+	hasher.Reset()
+
 	// This is actually really simple, it's just a sha1 of a sha1 displayed as hex
 	// (with a leading * to indicate the 'new' password hash of MySql)
 	hasher.Write([]byte(pass))
 	interm := hasher.Sum(nil)
 	hasher.Reset()
 	hasher.Write(interm)
+
 	return "*" + hex.EncodeToString(hasher.Sum(nil))
 }

MySQL_test.go

@@ -0,0 +1,33 @@
+package passwords
+
+import (
+	"testing"
+)
+
+const (
+	mySQLFail = "Password '%s' encrypted by MySQL should have been '%s'; got '%s'."
+)
+
+var (
+	validMySQLPasswords = map[string]string{
+		"Password1": "*7ee969bbe0a3985c8bff9fa65a06345c67fe434a",
+		"password":  "*2470c0c06dee42fd1618bb99005adca2ec9d1e19",
+		"recover":   "*71383c96a85618165875eb3f9d9e52179c3291e7",
+		"incorrect": "*2f8bcdbfd7618656393be67f7f1d8ccfaa87f8fc",
+	}
+)
+
+func TestMySQL(t *testing.T) {
+	for plain, encrypted := range validMySQLPasswords {
+		got := MySQL(plain)
+		if encrypted != got {
+			t.Fatalf(mySQLFail, plain, encrypted, got)
+		}
+	}
+}
+
+func BenchmarkMySQL(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		MySQL("A slightly longer thing to encrypt")
+	}
+}

passwords.sublime-project

@@ -0,0 +1,9 @@
+{
+	"folders":
+	[
+		{
+			"follow_symlinks": true,
+			"path": "."
+		}
+	]
+}

pools.go

@@ -0,0 +1,17 @@
+package passwords
+
+import (
+	"crypto/sha1"
+	"sync"
+)
+
+// This block contains various pools for resources we constantly need; mosty hashers and encoders.
+var (
+	sha1Pool = sync.Pool{
+		New: sha1New,
+	}
+)
+
+func sha1New() interface{} {
+	return sha1.New()
+}