Merge pull request libgit2#26 from carlosmn/ref-iter

Implement a reference iterator

Author: Vicent Martí

git.go

@@ -8,6 +8,7 @@ package git
 import "C"
 import (
 	"bytes"
+	"errors"
 	"unsafe"
 	"strings"
 )
@@ -18,6 +19,10 @@ const (
 	ENOTFOUND = C.GIT_ENOTFOUND
 )
 
+var (
+	ErrIterOver = errors.New("Iteration is over")
+)
+
 func init() {
 	C.git_threads_init()
 }

reference.go

@@ -111,3 +111,76 @@ func (v *Reference) Free() {
 	runtime.SetFinalizer(v, nil)
 	C.git_reference_free(v.ptr)
 }
+
+type ReferenceIterator struct {
+	ptr  *C.git_reference_iterator
+	repo *Repository
+}
+
+// NewReferenceIterator creates a new iterator over reference names
+func (repo *Repository) NewReferenceIterator() (*ReferenceIterator, error) {
+	var ptr *C.git_reference_iterator
+	ret := C.git_reference_iterator_new(&ptr, repo.ptr)
+	if ret < 0 {
+		return nil, LastError()
+	}
+
+	iter := &ReferenceIterator{repo: repo, ptr: ptr}
+	runtime.SetFinalizer(iter, (*ReferenceIterator).Free)
+	return iter, nil
+}
+
+// NewReferenceIteratorGlob creates an iterator over reference names
+// that match the speicified glob. The glob is of the usual fnmatch
+// type.
+func (repo *Repository) NewReferenceIteratorGlob(glob string) (*ReferenceIterator, error) {
+	cstr := C.CString(glob)
+	defer C.free(unsafe.Pointer(cstr))
+	var ptr *C.git_reference_iterator
+	ret := C.git_reference_iterator_glob_new(&ptr, repo.ptr, cstr)
+	if ret < 0 {
+		return nil, LastError()
+	}
+
+	iter := &ReferenceIterator{repo: repo, ptr: ptr}
+	runtime.SetFinalizer(iter, (*ReferenceIterator).Free)
+	return iter, nil
+}
+
+// Next retrieves the next reference name. If the iteration is over,
+// the returned error is git.ErrIterOver
+func (v *ReferenceIterator) Next() (string, error) {
+	var ptr *C.char
+	ret := C.git_reference_next(&ptr, v.ptr)
+	if ret == ITEROVER {
+		return "", ErrIterOver
+	}
+	if ret < 0 {
+		return "", LastError()
+	}
+
+	return C.GoString(ptr), nil
+}
+
+// Create a channel from the iterator. You can use range on the
+// returned channel to iterate over all the references. The channel
+// will be closed in case any error is found.
+func (v *ReferenceIterator) Iter() <-chan string {
+	ch := make(chan string)
+	go func() {
+		defer close(ch)
+		name, err := v.Next()
+		for err == nil {
+			ch <- name
+			name, err = v.Next()
+		}
+	}()
+
+	return ch
+}
+
+// Free the reference iterator
+func (v *ReferenceIterator) Free() {
+	runtime.SetFinalizer(v, nil)
+	C.git_reference_iterator_free(v.ptr)
+}

reference_test.go

@@ -3,6 +3,7 @@ package git
 import (
 	"os"
 	"runtime"
+	"sort"
 	"testing"
 	"time"
 )
@@ -71,6 +72,97 @@ func TestRefModification(t *testing.T) {
 
 }
 
+func TestIterator(t *testing.T) {
+	repo := createTestRepo(t)
+	defer os.RemoveAll(repo.Workdir())
+
+	loc, err := time.LoadLocation("Europe/Berlin")
+	checkFatal(t, err)
+	sig := &Signature{
+		Name:  "Rand Om Hacker",
+		Email: "[email protected]",
+		When:  time.Date(2013, 03, 06, 14, 30, 0, 0, loc),
+	}
+
+	idx, err := repo.Index()
+	checkFatal(t, err)
+	err = idx.AddByPath("README")
+	checkFatal(t, err)
+	treeId, err := idx.WriteTree()
+	checkFatal(t, err)
+
+	message := "This is a commit\n"
+	tree, err := repo.LookupTree(treeId)
+	checkFatal(t, err)
+	commitId, err := repo.CreateCommit("HEAD", sig, sig, message, tree)
+	checkFatal(t, err)
+
+	_, err = repo.CreateReference("refs/heads/one", commitId, true)
+	checkFatal(t, err)
+
+	_, err = repo.CreateReference("refs/heads/two", commitId, true)
+	checkFatal(t, err)
+
+	_, err = repo.CreateReference("refs/heads/three", commitId, true)
+	checkFatal(t, err)
+
+	iter, err := repo.NewReferenceIterator()
+	checkFatal(t, err)
+
+	var list []string
+	expected := []string{
+		"refs/heads/master",
+		"refs/heads/one",
+		"refs/heads/three",
+		"refs/heads/two",
+	}
+
+	// test some manual iteration
+	name, err := iter.Next()
+	for err == nil {
+		list = append(list, name)
+		name, err = iter.Next()
+	}
+	if err != ErrIterOver {
+		t.Fatal("Iteration not over")
+	}
+
+
+	sort.Strings(list)
+	compareStringList(t, expected, list)
+
+	// test the channel iteration
+	list = []string{}
+	iter, err = repo.NewReferenceIterator()
+	for name := range iter.Iter() {
+		list = append(list, name)
+	}
+
+	sort.Strings(list)
+	compareStringList(t, expected, list)
+
+	iter, err = repo.NewReferenceIteratorGlob("refs/heads/t*")
+	expected = []string{
+		"refs/heads/three",
+		"refs/heads/two",
+	}
+
+	list = []string{}
+	for name := range iter.Iter() {
+		list = append(list, name)
+	}
+
+	compareStringList(t, expected, list)
+}
+
+func compareStringList(t *testing.T, expected, actual []string) {
+	for i, v := range expected {
+		if actual[i] != v {
+			t.Fatalf("Bad list")
+		}
+	}
+}
+
 func checkRefType(t *testing.T, ref *Reference, kind int) {
 	if ref.Type() == kind {
 		return