Remote: reorg push

The Remote interface mixes the configuration of a remote with overriding
the configuration for a paritcular operation. This makes the remotes
trickier to use than they should be.

Move towards letting the user specify the refspecs and callbacks they
want for a particular Fetch() operation intsead of setting it for a
Remote object that they then need to throw away.

git.go

@@ -91,6 +91,7 @@ const (
 
 var (
 	ErrInvalid = errors.New("Invalid state for operation")
+	ErrPushUnpack = errors.New("Error unpacking on the remote end")
 )
 
 func init() {

remote.go

@@ -2,9 +2,10 @@ package git
 
 /*
 #include <git2.h>
-#include <git2/errors.h>
 
 extern void _go_git_setup_callbacks(git_remote_callbacks *callbacks);
+int _go_git_push_status_foreach(git_push *push, void *data);
+int _go_git_push_set_callbacks(git_push *push, void *packbuilder_progress_data, void *transfer_progress_data);
 
 */
 import "C"
@@ -409,7 +410,7 @@ func (o *Remote) PushRefspecs() ([]string, error) {
 	return refspecs, nil
 }
 
-func (o *Remote) SetPushRefspecs(refspecs []string) error {
+func setPushRefspecs(remote *C.git_remote, refspecs []string) error {
 	crefspecs := C.git_strarray{}
 	crefspecs.count = C.size_t(len(refspecs))
 	crefspecs.strings = makeCStringsFromStrings(refspecs)
@@ -418,13 +419,17 @@ func (o *Remote) SetPushRefspecs(refspecs []string) error {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	ret := C.git_remote_set_push_refspecs(o.ptr, &crefspecs)
+	ret := C.git_remote_set_push_refspecs(remote, &crefspecs)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
 	return nil
 }
 
+func (o *Remote) SetPushRefspecs(refspecs []string) error {
+	return setPushRefspecs(o.ptr, refspecs)
+}
+
 func (o *Remote) ClearRefspecs() {
 	C.git_remote_clear_refspecs(o.ptr)
 }
@@ -433,7 +438,24 @@ func (o *Remote) RefspecCount() uint {
 	return uint(C.git_remote_refspec_count(o.ptr))
 }
 
-func (o *Remote) Fetch(sig *Signature, msg string) error {
+func (o *Remote) Fetch(refspecs []string, callbacks *RemoteCallbacks, sig *Signature, msg string) error {
+
+	var remote *C.git_remote
+	if ret := C.git_remote_dup(&remote, o.ptr); ret < 0 {
+		return MakeGitError(ret)
+	}
+	defer C.git_remote_free(remote)
+
+	var ccallbacks C.git_remote_callbacks
+	populateRemoteCallbacks(&ccallbacks, callbacks)
+	C.git_remote_set_callbacks(remote, &ccallbacks)
+
+	if refspecs != nil {
+		err := setPushRefspecs(remote, refspecs)
+		if err != nil {
+			return err
+		}
+	}
 
 	var csig *C.git_signature = nil
 	if sig != nil {
@@ -448,9 +470,79 @@ func (o *Remote) Fetch(sig *Signature, msg string) error {
 		cmsg = C.CString(msg)
 		defer C.free(unsafe.Pointer(cmsg))
 	}
-	ret := C.git_remote_fetch(o.ptr, csig, cmsg)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_remote_fetch(remote, csig, cmsg)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
 	return nil
 }
+
+func (o *Remote) Push(refspecs []string, callbacks *PushCallbacks, opts PushOptions, statusForeach StatusForeachFunc, sig *Signature, msg string) error {
+	var remote *C.git_remote
+	if ret := C.git_remote_dup(&remote, o.ptr); ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	var push *C.git_push
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	if ret := C.git_push_new(&push, o.ptr); ret < 0 {
+		return MakeGitError(ret)
+	}
+	defer C.git_push_free(push)
+
+	for _, str := range refspecs {
+		cstr := C.CString(str)
+		defer C.free(unsafe.Pointer(cstr))
+
+		if ret := C.git_push_add_refspec(push, cstr); ret < 0 {
+			return MakeGitError(ret)
+		}
+	}
+
+	copts := C.git_push_options{
+		version:        C.uint(opts.Version),
+		pb_parallelism: C.uint(opts.PbParallelism),
+	}
+
+	if ret := C.git_push_set_options(push, &copts); ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	if ret := C.git_push_finish(push); ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	if C.git_push_unpack_ok(push) == 0 {
+		return ErrPushUnpack
+	}
+
+	if ret := C._go_git_push_status_foreach(push, unsafe.Pointer(&statusForeach)); ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	var csig *C.git_signature = nil
+	if sig != nil {
+		csig = sig.toC()
+		defer C.free(unsafe.Pointer(csig))
+	}
+
+	var cmsg *C.char
+	if msg == "" {
+		cmsg = nil
+	} else {
+		cmsg = C.CString(msg)
+		defer C.free(unsafe.Pointer(cmsg))
+	}
+	if ret := C.git_push_update_tips(push, csig, cmsg); ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}