parse: implement `git_parse_peek`

Some code parts need to inspect the next few bytes without actually
consuming it yet, for example to examine what content it has to expect
next. Create a new function `git_parse_peek` which returns the next byte
without modifying the parsing context and use it at multiple call sites.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/parse.h b/src/parse.h
index 8112eaeef..419014e93 100644
--- a/src/parse.h
+++ b/src/parse.h
@@ -48,3 +48,9 @@ int git_parse_advance_expected(
 int git_parse_advance_ws(git_parse_ctx *ctx);
 int git_parse_advance_nl(git_parse_ctx *ctx);
 int git_parse_advance_digit(int64_t *out, git_parse_ctx *ctx, int base);
+
+enum GIT_PARSE_PEEK_FLAGS {
+	GIT_PARSE_PEEK_SKIP_WHITESPACE = (1 << 0)
+};
+
+int git_parse_peek(char *out, git_parse_ctx *ctx, int flags);