Use git_buf for path storage instead of stack-based buffers

This converts virtually all of the places that allocate GIT_PATH_MAX
buffers on the stack for manipulating paths to use git_buf objects
instead.  The patch is pretty careful not to touch the public API
for libgit2, so there are a few places that still use GIT_PATH_MAX.

This extends and changes some details of the git_buf implementation
to add a couple of extra functions and to make error handling easier.

This includes serious alterations to all the path.c functions, and
several of the fileops.c ones, too.  Also, there are a number of new
functions that parallel existing ones except that use a git_buf
instead of a stack-based buffer (such as git_config_find_global_r
that exists alongsize git_config_find_global).

This also modifies the win32 version of p_realpath to allocate whatever
buffer size is needed to accommodate the realpath instead of hardcoding
a GIT_PATH_MAX limit, but that change needs to be tested still.

1 files changed, 12 insertions, 0 deletions

diff --git a/src/refspec.h b/src/refspec.h
index 7c389719b..cd9f894bf 100644
--- a/src/refspec.h
+++ b/src/refspec.h
@@ -8,6 +8,7 @@
 #define INCLUDE_refspec_h__
 
 #include "git2/refspec.h"
+#include "buffer.h"
 
 struct git_refspec {
 	struct git_refspec *next;
@@ -20,4 +21,15 @@ struct git_refspec {
 
 int git_refspec_parse(struct git_refspec *refspec, const char *str);
 
+/**
+ * Transform a reference to its target following the refspec's rules,
+ * and writes the results into a git_buf.
+ *
+ * @param out where to store the target name
+ * @param spec the refspec
+ * @param name the name of the reference to transform
+ * @return GIT_SUCCESS or error if buffer allocation fails
+ */
+int git_refspec_transform_r(git_buf *out, const git_refspec *spec, const char *name);
+
 #endif