format: index, Index.Entry method

2 files changed, 39 insertions, 5 deletions

diff --git a/plumbing/format/index/index.go b/plumbing/format/index/index.go
index 61e7d66..402a48e 100644
--- a/plumbing/format/index/index.go
+++ b/plumbing/format/index/index.go
@@ -1,20 +1,21 @@
 package index
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"time"
 
-	"bytes"
-
 	"gopkg.in/src-d/go-git.v4/plumbing"
 	"gopkg.in/src-d/go-git.v4/plumbing/filemode"
 )
 
 var (
-	// ErrUnsupportedVersion is returned by Decode when the idxindex file
-	// version is not supported.
-	ErrUnsupportedVersion = errors.New("Unsuported version")
+	// ErrUnsupportedVersion is returned by Decode when the index file version
+	// is not supported.
+	ErrUnsupportedVersion = errors.New("unsupported version")
+	// ErrEntryNotFound is returned by Index.Entry, if an entry is not found.
+	ErrEntryNotFound = errors.New("entry not found")
 
 	indexSignature          = []byte{'D', 'I', 'R', 'C'}
 	treeExtSignature        = []byte{'T', 'R', 'E', 'E'}
@@ -50,6 +51,17 @@ type Index struct {
 	ResolveUndo *ResolveUndo
 }
 
+// Entry returns the entry that match the given path, if any.
+func (i *Index) Entry(path string) (Entry, error) {
+	for _, e := range i.Entries {
+		if e.Name == path {
+			return e, nil
+		}
+	}
+
+	return Entry{}, ErrEntryNotFound
+}
+
 // String is equivalent to `git ls-files --stage --debug`
 func (i *Index) String() string {
 	buf := bytes.NewBuffer(nil)
diff --git a/plumbing/format/index/index_test.go b/plumbing/format/index/index_test.go
new file mode 100644
index 0000000..8c915d8
--- /dev/null
+++ b/plumbing/format/index/index_test.go
@@ -0,0 +1,22 @@
+package index
+
+import (
+	. "gopkg.in/check.v1"
+)
+
+func (s *IndexSuite) TestIndexEntry(c *C) {
+	idx := &Index{
+		Entries: []Entry{
+			{Name: "foo", Size: 42},
+			{Name: "bar", Size: 82},
+		},
+	}
+
+	e, err := idx.Entry("foo")
+	c.Assert(err, IsNil)
+	c.Assert(e.Name, Equals, "foo")
+
+	e, err = idx.Entry("missing")
+	c.Assert(err, Equals, ErrEntryNotFound)
+	c.Assert(e.Name, Equals, "")
+}