From b5a87fdf7316b7c50419e13ffd518d4466306071 Mon Sep 17 00:00:00 2001
From: Paul Okstad <tobyisapup@icloud.com>
Date: Sun, 27 Dec 2020 10:17:38 -0800
Subject: [PATCH] Reflog support (#467)

---
 reflog.go | 175 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 175 insertions(+)
 create mode 100644 reflog.go

diff --git a/reflog.go b/reflog.go
new file mode 100644
index 00000000..10760a79
--- /dev/null
+++ b/reflog.go
@@ -0,0 +1,175 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+import (
+	"runtime"
+	"unsafe"
+)
+
+// RefLog is a log of changes for a reference
+type RefLog struct {
+	ptr  *C.git_reflog
+	repo *Repository
+	name string
+}
+
+func newRefLogFromC(ptr *C.git_reflog, repo *Repository, name string) *RefLog {
+	l := &RefLog{
+		ptr:  ptr,
+		repo: repo,
+		name: name,
+	}
+	runtime.SetFinalizer(l, (*RefLog).Free)
+	return l
+}
+
+func (repo *Repository) ReadRefLog(name string) (*RefLog, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	var ptr *C.git_reflog
+
+	ecode := C.git_reflog_read(&ptr, repo.ptr, cname)
+	runtime.KeepAlive(repo)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+
+	return newRefLogFromC(ptr, repo, name), nil
+}
+
+func (repo *Repository) DeleteReflog(name string) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	ecode := C.git_reflog_delete(repo.ptr, cname)
+	runtime.KeepAlive(repo)
+	if ecode < 0 {
+		return MakeGitError(ecode)
+	}
+
+	return nil
+}
+
+func (repo *Repository) RenameReflog(oldName, newName string) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cOldName := C.CString(oldName)
+	defer C.free(unsafe.Pointer(cOldName))
+
+	cNewName := C.CString(newName)
+	defer C.free(unsafe.Pointer(cNewName))
+
+	ecode := C.git_reflog_rename(repo.ptr, cOldName, cNewName)
+	runtime.KeepAlive(repo)
+	if ecode < 0 {
+		return MakeGitError(ecode)
+	}
+
+	return nil
+}
+
+func (l *RefLog) Write() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_reflog_write(l.ptr)
+	runtime.KeepAlive(l)
+	if ecode < 0 {
+		return MakeGitError(ecode)
+	}
+	return nil
+}
+
+func (l *RefLog) EntryCount() uint {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	count := C.git_reflog_entrycount(l.ptr)
+	runtime.KeepAlive(l)
+	return uint(count)
+}
+
+// RefLogEntry specifies a reference change
+type RefLogEntry struct {
+	Old       *Oid
+	New       *Oid
+	Committer *Signature
+	Message   string // may be empty
+}
+
+func newRefLogEntry(entry *C.git_reflog_entry) *RefLogEntry {
+	return &RefLogEntry{
+		New:       newOidFromC(C.git_reflog_entry_id_new(entry)),
+		Old:       newOidFromC(C.git_reflog_entry_id_old(entry)),
+		Committer: newSignatureFromC(C.git_reflog_entry_committer(entry)),
+		Message:   C.GoString(C.git_reflog_entry_message(entry)),
+	}
+}
+
+func (l *RefLog) EntryByIndex(index uint) *RefLogEntry {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	entry := C.git_reflog_entry_byindex(l.ptr, C.size_t(index))
+	if entry == nil {
+		return nil
+	}
+
+	goEntry := newRefLogEntry(entry)
+	runtime.KeepAlive(l)
+
+	return goEntry
+}
+
+func (l *RefLog) DropEntry(index uint, rewriteHistory bool) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var rewriteHistoryInt int
+	if rewriteHistory {
+		rewriteHistoryInt = 1
+	}
+
+	ecode := C.git_reflog_drop(l.ptr, C.size_t(index), C.int(rewriteHistoryInt))
+	runtime.KeepAlive(l)
+	if ecode < 0 {
+		return MakeGitError(ecode)
+	}
+
+	return nil
+}
+
+func (l *RefLog) AppendEntry(oid *Oid, committer *Signature, message string) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cSignature, err := committer.toC()
+	if err != nil {
+		return err
+	}
+	defer C.git_signature_free(cSignature)
+
+	cMsg := C.CString(message)
+	defer C.free(unsafe.Pointer(cMsg))
+
+	C.git_reflog_append(l.ptr, oid.toC(), cSignature, cMsg)
+	runtime.KeepAlive(l)
+
+	return nil
+}
+
+func (l *RefLog) Free() {
+	runtime.SetFinalizer(l, nil)
+	C.git_reflog_free(l.ptr)
+}