RFC: A proposal for setting callbacks

examples/network/fetch.c

@@ -39,7 +39,7 @@ static void *download(void *ptr)
 	pthread_exit(&data->ret);
 }
 
-int update_cb(const char *refname, const git_oid *a, const git_oid *b)
+int update_cb(const char *refname, const git_oid *a, const git_oid *b, void *data)
 {
 	const char *action;
 	char a_str[GIT_OID_HEXSZ+1], b_str[GIT_OID_HEXSZ+1];
@@ -58,6 +58,19 @@ int update_cb(const char *refname, const git_oid *a, const git_oid *b)
 	return 0;
 }
 
+int progress_cb(const char *str, void *data)
+{
+	fputs(str, stderr);
+	return 0;
+}
+
+int error_cb(const char *str, void *data)
+{
+	fputs("The world is ending!", stderr);
+	fputs(str, stderr);
+	return 0;
+}
+
 int fetch(git_repository *repo, int argc, char **argv)
 {
 	git_remote *remote = NULL;
@@ -73,6 +86,10 @@ int fetch(git_repository *repo, int argc, char **argv)
 			return -1;
 	}
 
+	git_remote_callback(remote, GIT_CALLBACK_PROGRESS, progress_cb, NULL);
+	git_remote_callback(remote, GIT_CALLBACK_ERROR, error_cb, NULL);
+	git_remote_callback(remote, GIT_CALLBACK_UPDATE_TIPS, update_cb, NULL);
+
 	// Set up the information for the background worker thread
 	data.remote = remote;
 	data.bytes = &bytes;
@@ -100,7 +117,7 @@ int fetch(git_repository *repo, int argc, char **argv)
 	// right commits. This may be needed even if there was no packfile
 	// to download, which can happen e.g. when the branches have been
 	// changed but all the neede objects are available locally.
-	if (git_remote_update_tips(remote, update_cb) < 0)
+	if (git_remote_update_tips(remote) < 0)
 		return -1;
 
 	git_remote_free(remote);

include/git2/remote.h

@@ -190,7 +190,7 @@ GIT_EXTERN(void) git_remote_free(git_remote *remote);
  * @param remote the remote to update
  * @param cb callback to run on each ref update. 'a' is the old value, 'b' is then new value
  */
-GIT_EXTERN(int) git_remote_update_tips(git_remote *remote, int (*cb)(const char *refname, const git_oid *a, const git_oid *b));
+GIT_EXTERN(int) git_remote_update_tips(git_remote *remote);
 
 /**
  * Return whether a string is a valid remote URL
@@ -229,6 +229,25 @@ GIT_EXTERN(int) git_remote_list(git_strarray *remotes_list, git_repository *repo
  */
 GIT_EXTERN(int) git_remote_add(git_remote **out, git_repository *repo, const char *name, const char *url);
 
+typedef enum {
+	GIT_CALLBACK_PROGRESS,
+	GIT_CALLBACK_ERROR,
+	GIT_CALLBACK_AUTH,
+	GIT_CALLBACK_UPDATE_TIPS,
+	GIT_CALLBACK_DONE,
+} git_callback_t;
+
+typedef int (*git_update_tips_cb)(const char *refname, const git_oid *a, const git_oid *b, void *data);
+/**
+ * Set a callback for a particular event
+ *
+ * @param remote The remote to act on
+ * @param opt Which callback to set
+ * @param callback function pointer to the callback
+ * @param data user-supplied data to pass to the callback
+ */
+GIT_EXTERN(int) git_remote_callback(git_remote *remote, git_callback_t opt, void *callback, void *data);
+
 /** @} */
 GIT_END_DECL
 #endif

src/remote.c

@@ -324,7 +324,7 @@ int git_remote_download(git_remote *remote, git_off_t *bytes, git_indexer_stats
 	return git_fetch_download_pack(remote, bytes, stats);
 }
 
-int git_remote_update_tips(git_remote *remote, int (*cb)(const char *refname, const git_oid *a, const git_oid *b))
+int git_remote_update_tips(git_remote *remote)
 {
 	int error = 0;
 	unsigned int i = 0;
@@ -371,8 +371,8 @@ int git_remote_update_tips(git_remote *remote, int (*cb)(const char *refname, co
 
 		git_reference_free(ref);
 
-		if (cb != NULL) {
-			if (cb(refname.ptr, &old, &head->oid) < 0)
+		if (remote->update_tips != NULL) {
+			if (remote->update_tips(refname.ptr, &old, &head->oid, remote->update_tips_data) < 0)
 				goto on_error;
 		}
 	}
@@ -386,6 +386,22 @@ int git_remote_update_tips(git_remote *remote, int (*cb)(const char *refname, co
 
 }
 
+int git_remote_callback(git_remote *remote, git_callback_t opt, void *fn, void *data)
+{
+	switch (opt) {
+	case GIT_CALLBACK_UPDATE_TIPS:
+		remote->update_tips = (git_update_tips_cb)fn;
+		remote->update_tips_data = data;
+		break;
+	default:
+		/* Set an error when we do this for real */
+		return -1;
+		break;
+	}
+
+	return 0;
+}
+
 int git_remote_connected(git_remote *remote)
 {
 	assert(remote);

src/remote.h

@@ -20,6 +20,8 @@ struct git_remote {
 	git_transport *transport;
 	git_repository *repo;
 	unsigned int need_pack:1;
+	git_update_tips_cb update_tips;
+	void *update_tips_data;
 };
 
 #endif