strutil: add PathIterator.Depth

This patch adds simple "depth" tracking to the path iterator. This allows to ask the iterator for a reliable directory count rather than having to keep track of that separately. Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com> 

2 files changed, 32 insertions, 0 deletions

diff --git a/strutil/pathiter.go b/strutil/pathiter.go
index 460ca5356d..7f88c50f51 100644
--- a/strutil/pathiter.go
+++ b/strutil/pathiter.go
@@ -43,6 +43,7 @@ import (
 type PathIterator struct {
	path string
	left, right int
+	depth int
 }
 
 // NewPathIterator returns an iterator for traversing the given path.
@@ -84,6 +85,14 @@ func (iter *PathIterator) CurrentBase() string {
	return iter.path[:iter.left]
 }
 
+// Depth returns the directory depth of the current path.
+//
+// This is equal to the number of traversed directories, including that of the
+// root directory.
+func (iter *PathIterator) Depth() int {
+	return iter.depth
+}
+
 // Next advances the iterator to the next name, returning true if one is found.
 //
 // If this method returns false then no change is made and all helper methods
@@ -117,5 +126,6 @@ func (iter *PathIterator) Next() bool {
	} else {
	iter.right = len(iter.path)
	}
+	iter.depth++
	return true
 }
diff --git a/strutil/pathiter_test.go b/strutil/pathiter_test.go
index 7f5ab2c1f8..74577b8c31 100644
--- a/strutil/pathiter_test.go
+++ b/strutil/pathiter_test.go
@@ -39,60 +39,72 @@ func (s *pathIterSuite) TestPathIteratorFilename(c *C) {
	iter, err := strutil.NewPathIterator("foo")
	c.Assert(err, IsNil)
	c.Assert(iter.Path(), Equals, "foo")
+	c.Assert(iter.Depth(), Equals, 0)
 
	c.Assert(iter.Next(), Equals, true)
	c.Assert(iter.CurrentBase(), Equals, "")
	c.Assert(iter.CurrentPath(), Equals, "foo")
	c.Assert(iter.CurrentName(), Equals, "foo")
	c.Assert(iter.CurrentCleanName(), Equals, "foo")
+	c.Assert(iter.Depth(), Equals, 1)
 
	c.Assert(iter.Next(), Equals, false)
+	c.Assert(iter.Depth(), Equals, 1)
 }
 
 func (s *pathIterSuite) TestPathIteratorRelative(c *C) {
	iter, err := strutil.NewPathIterator("foo/bar")
	c.Assert(err, IsNil)
	c.Assert(iter.Path(), Equals, "foo/bar")
+	c.Assert(iter.Depth(), Equals, 0)
 
	c.Assert(iter.Next(), Equals, true)
	c.Assert(iter.CurrentBase(), Equals, "")
	c.Assert(iter.CurrentPath(), Equals, "foo/")
	c.Assert(iter.CurrentName(), Equals, "foo/")
	c.Assert(iter.CurrentCleanName(), Equals, "foo")
+	c.Assert(iter.Depth(), Equals, 1)
 
	c.Assert(iter.Next(), Equals, true)
	c.Assert(iter.CurrentBase(), Equals, "foo/")
	c.Assert(iter.CurrentPath(), Equals, "foo/bar")
	c.Assert(iter.CurrentName(), Equals, "bar")
	c.Assert(iter.CurrentCleanName(), Equals, "bar")
+	c.Assert(iter.Depth(), Equals, 2)
 
	c.Assert(iter.Next(), Equals, false)
+	c.Assert(iter.Depth(), Equals, 2)
 }
 
 func (s *pathIterSuite) TestPathIteratorAbsoluteClean(c *C) {
	iter, err := strutil.NewPathIterator("/foo/bar")
	c.Assert(err, IsNil)
	c.Assert(iter.Path(), Equals, "/foo/bar")
+	c.Assert(iter.Depth(), Equals, 0)
 
	c.Assert(iter.Next(), Equals, true)
	c.Assert(iter.CurrentBase(), Equals, "")
	c.Assert(iter.CurrentPath(), Equals, "/")
	c.Assert(iter.CurrentName(), Equals, "/")
	c.Assert(iter.CurrentCleanName(), Equals, "")
+	c.Assert(iter.Depth(), Equals, 1)
 
	c.Assert(iter.Next(), Equals, true)
	c.Assert(iter.CurrentBase(), Equals, "/")
	c.Assert(iter.CurrentPath(), Equals, "/foo/")
	c.Assert(iter.CurrentName(), Equals, "foo/")
	c.Assert(iter.CurrentCleanName(), Equals, "foo")
+	c.Assert(iter.Depth(), Equals, 2)
 
	c.Assert(iter.Next(), Equals, true)
	c.Assert(iter.CurrentBase(), Equals, "/foo/")
	c.Assert(iter.CurrentPath(), Equals, "/foo/bar")
	c.Assert(iter.CurrentName(), Equals, "bar")
	c.Assert(iter.CurrentCleanName(), Equals, "bar")
+	c.Assert(iter.Depth(), Equals, 3)
 
	c.Assert(iter.Next(), Equals, false)
+	c.Assert(iter.Depth(), Equals, 3)
 }
 
 func (s *pathIterSuite) TestPathIteratorAbsoluteUnclean(c *C) {
@@ -105,14 +117,17 @@ func (s *pathIterSuite) TestPathIteratorRootDir(c *C) {
	iter, err := strutil.NewPathIterator("/")
	c.Assert(err, IsNil)
	c.Assert(iter.Path(), Equals, "/")
+	c.Assert(iter.Depth(), Equals, 0)
 
	c.Assert(iter.Next(), Equals, true)
	c.Assert(iter.CurrentBase(), Equals, "")
	c.Assert(iter.CurrentPath(), Equals, "/")
	c.Assert(iter.CurrentName(), Equals, "/")
	c.Assert(iter.CurrentCleanName(), Equals, "")
+	c.Assert(iter.Depth(), Equals, 1)
 
	c.Assert(iter.Next(), Equals, false)
+	c.Assert(iter.Depth(), Equals, 1)
 }
 
 func (s *pathIterSuite) TestPathIteratorUncleanPath(c *C) {
@@ -125,32 +140,38 @@ func (s *pathIterSuite) TestPathIteratorUnicode(c *C) {
	iter, err := strutil.NewPathIterator("/zażółć/gęślą/jaźń")
	c.Assert(err, IsNil)
	c.Assert(iter.Path(), Equals, "/zażółć/gęślą/jaźń")
+	c.Assert(iter.Depth(), Equals, 0)
 
	c.Assert(iter.Next(), Equals, true)
	c.Assert(iter.CurrentBase(), Equals, "")
	c.Assert(iter.CurrentPath(), Equals, "/")
	c.Assert(iter.CurrentName(), Equals, "/")
	c.Assert(iter.CurrentCleanName(), Equals, "")
+	c.Assert(iter.Depth(), Equals, 1)
 
	c.Assert(iter.Next(), Equals, true)
	c.Assert(iter.CurrentBase(), Equals, "/")
	c.Assert(iter.CurrentPath(), Equals, "/zażółć/")
	c.Assert(iter.CurrentName(), Equals, "zażółć/")
	c.Assert(iter.CurrentCleanName(), Equals, "zażółć")
+	c.Assert(iter.Depth(), Equals, 2)
 
	c.Assert(iter.Next(), Equals, true)
	c.Assert(iter.CurrentBase(), Equals, "/zażółć/")
	c.Assert(iter.CurrentPath(), Equals, "/zażółć/gęślą/")
	c.Assert(iter.CurrentName(), Equals, "gęślą/")
	c.Assert(iter.CurrentCleanName(), Equals, "gęślą")
+	c.Assert(iter.Depth(), Equals, 3)
 
	c.Assert(iter.Next(), Equals, true)
	c.Assert(iter.CurrentBase(), Equals, "/zażółć/gęślą/")
	c.Assert(iter.CurrentPath(), Equals, "/zażółć/gęślą/jaźń")
	c.Assert(iter.CurrentName(), Equals, "jaźń")
	c.Assert(iter.CurrentCleanName(), Equals, "jaźń")
+	c.Assert(iter.Depth(), Equals, 4)
 
	c.Assert(iter.Next(), Equals, false)
+	c.Assert(iter.Depth(), Equals, 4)
 }
 
 func (s *pathIterSuite) TestPathIteratorExample(c *C) {
@@ -161,5 +182,6 @@ func (s *pathIterSuite) TestPathIteratorExample(c *C) {
	_ = iter.CurrentPath()
	_ = iter.CurrentName()
	_ = iter.CurrentCleanName()
+	_ = iter.Depth()
	}
 }