commit/tag: ensure the message is cleaned up

'git commit' and 'git tag -a' enforce some conventions, like cleaning up excess whitespace and making sure that the last line ends with a '\n'. This fix replicates this behavior.

Fix libgit2/libgit2sharp#117

1 files changed, 54 insertions, 0 deletions

diff --git a/src/message.c b/src/message.c
new file mode 100644
index 000000000..94745ea81
--- /dev/null
+++ b/src/message.c
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2009-2012 the libgit2 contributors
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "message.h"
+
+static size_t line_length_without_trailing_spaces(const char *line, size_t len)
+{
+	while (len) {
+		unsigned char c = line[len - 1];
+		if (!isspace(c))
+			break;
+		len--;
+	}
+
+	return len;
+}
+
+/* Greatly inspired from git.git "stripspace" */
+/* see https://github.com/git/git/blob/497215d8811ac7b8955693ceaad0899ecd894ed2/builtin/stripspace.c#L4-67 */
+int git_message_prettify(git_buf *message_out, const char *message, int strip_comments)
+{
+	int consecutive_empty_lines = 0;
+	size_t i, line_length, rtrimmed_line_length;
+	char *next_newline;
+
+	for (i = 0; i < strlen(message); i += line_length) {
+		next_newline = memchr(message + i, '\n', strlen(message) - i);
+		line_length = next_newline ? next_newline - (message + i) + 1 : strlen(message) - i;
+
+		if (strip_comments && line_length && message[i] == '#')
+			continue;
+
+		rtrimmed_line_length = line_length_without_trailing_spaces(message + i, line_length);
+
+		if (!rtrimmed_line_length) {
+			consecutive_empty_lines++;
+			continue;
+		}
+
+		if (consecutive_empty_lines > 0 && message_out->size > 0)
+			if (git_buf_putc(message_out, '\n') < 0)
+				return -1;
+
+		consecutive_empty_lines = 0;
+		git_buf_put(message_out, message + i, rtrimmed_line_length);
+		git_buf_putc(message_out, '\n');
+	}
+
+	return 0;
+}