Resolve comments from pull request

This converts the map validation function into a macro, tweaks
the GITERR_OS system error automatic appending, and adds a
tentative new error access API and some quick unit tests for
both the old and new error APIs.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/map.h b/src/map.h
index d0ca1ee56..96d879547 100644
--- a/src/map.h
+++ b/src/map.h
@@ -31,7 +31,10 @@ typedef struct { /* memory mapped buffer	*/
 #endif
 } git_map;
 
-extern int validate_map_args(git_map *out, size_t len, int prot, int flags, int fd, git_off_t offset);
+#define GIT_MMAP_VALIDATE(out, len, prot, flags) do { \
+	assert(out != NULL && len > 0); \
+	assert((prot & GIT_PROT_WRITE) || (prot & GIT_PROT_READ)); \
+	assert((flags & GIT_MAP_FIXED) == 0); } while (0)
 
 extern int p_mmap(git_map *out, size_t len, int prot, int flags, int fd, git_off_t offset);
 extern int p_munmap(git_map *map);