Merge lp:~chipaca/snappy/overwrite into lp:~snappy-dev/snappy/snappy-moved-to-github

[John Lenton]

Add CopyFileOverwrite flag and behaviour to helpers.CopyFile.

[Sergio Schvezov (sergiusens)]

\o/

review: Approve

[lp:~chipaca/snappy/overwrite]

546. By John Lenton on 2015-07-01

Add CopyFileOverwrite flag and behaviour to helpers.CopyFile. by chipaca approved by sergiusens

=== modified file 'helpers/cp.go'
--- helpers/cp.go	2015-05-15 15:38:17 +0000
+++ helpers/cp.go	2015-07-01 20:52:02 +0000
@@ -33,6 +33,8 @@
 	CopyFlagDefault CopyFlag = 0
 	// CopyFlagSync does a sync after copying the files
 	CopyFlagSync CopyFlag = 1 << iota
+	// CopyFlagOverwrite overwrites the target if it exists
+	CopyFlagOverwrite
 )
 
 var (
@@ -70,7 +72,12 @@
 		return fmt.Errorf("unable to stat %s: %v", src, err)
 	}
 
-	fout, err := openfile(dst, os.O_WRONLY|os.O_CREATE|os.O_EXCL, fi.Mode())
+	outflags := os.O_WRONLY | os.O_CREATE
+	if flags&CopyFlagOverwrite == 0 {
+		outflags |= os.O_EXCL
+	}
+
+	fout, err := openfile(dst, outflags, fi.Mode())
 	if err != nil {
 		return fmt.Errorf("unable to create %s: %v", dst, err)
 	}

=== modified file 'helpers/cp_test.go'
--- helpers/cp_test.go	2015-06-02 20:46:07 +0000
+++ helpers/cp_test.go	2015-07-01 20:52:02 +0000
@@ -90,6 +90,21 @@
 	c.Check(bs, DeepEquals, s.data)
 }
 
+func (s *cpSuite) TestCpNoOverwrite(c *C) {
+	_, err := os.Create(s.f2)
+	c.Assert(err, IsNil)
+	c.Check(CopyFile(s.f1, s.f2, CopyFlagDefault), NotNil)
+}
+
+func (s *cpSuite) TestCpOverwrite(c *C) {
+	_, err := os.Create(s.f2)
+	c.Assert(err, IsNil)
+	c.Check(CopyFile(s.f1, s.f2, CopyFlagOverwrite), IsNil)
+	bs, err := ioutil.ReadFile(s.f2)
+	c.Check(err, IsNil)
+	c.Check(bs, DeepEquals, s.data)
+}
+
 func (s *cpSuite) TestCpSync(c *C) {
 	s.mock()
 	c.Check(CopyFile(s.f1, s.f2, CopyFlagDefault), IsNil)