thodg/libgit2

diff --git a/include/git2/config.h b/include/git2/config.h
index 56b5431..d0f1ba1 100644
--- a/include/git2/config.h
+++ b/include/git2/config.h
@@ -29,25 +29,28 @@ GIT_BEGIN_DECL
  * priority levels as well.
  */
 typedef enum {
+	/** System-wide on Windows, for compatibility with portable git */
+	GIT_CONFIG_LEVEL_PROGRAMDATA = 1,
+
 	/** System-wide configuration file; /etc/gitconfig on Linux systems */
-	GIT_CONFIG_LEVEL_SYSTEM = 1,
+	GIT_CONFIG_LEVEL_SYSTEM = 2,
 
 	/** XDG compatible configuration file; typically ~/.config/git/config */
-	GIT_CONFIG_LEVEL_XDG = 2,
+	GIT_CONFIG_LEVEL_XDG = 3,
 
 	/** User-specific configuration file (also called Global configuration
 	 * file); typically ~/.gitconfig
 	 */
-	GIT_CONFIG_LEVEL_GLOBAL = 3,
+	GIT_CONFIG_LEVEL_GLOBAL = 4,
 
 	/** Repository specific configuration file; $WORK_DIR/.git/config on
 	 * non-bare repos
 	 */
-	GIT_CONFIG_LEVEL_LOCAL = 4,
+	GIT_CONFIG_LEVEL_LOCAL = 5,
 
 	/** Application specific configuration file; freely defined by applications
 	 */
-	GIT_CONFIG_LEVEL_APP = 5,
+	GIT_CONFIG_LEVEL_APP = 6,
 
 	/** Represents the highest level available config file (i.e. the most
 	 * specific config file available that actually is loaded)
@@ -142,6 +145,17 @@ GIT_EXTERN(int) git_config_find_xdg(git_buf *out);
 GIT_EXTERN(int) git_config_find_system(git_buf *out);
 
 /**
+ * Locate the path to the configuration file in ProgramData
+ *
+ * Look for the file in %PROGRAMDATA%\Git\config used by portable git.
+ *
+ * @param out Pointer to a user-allocated git_buf in which to store the path
+ * @return 0 if a ProgramData configuration file has been
+ *	found. Its path will be stored in `out`.
+ */
+GIT_EXTERN(int) git_config_find_programdata(git_buf *out);
+
+/**
  * Open the global, XDG and system configuration files
  *
  * Utility wrapper that finds the global, XDG and system configuration files
diff --git a/src/config.c b/src/config.c
index f0b2c3a..f4d4cb2 100644
--- a/src/config.c
+++ b/src/config.c
@@ -1086,6 +1086,12 @@ int git_config_find_system(git_buf *path)
 	return git_sysdir_find_system_file(path, GIT_CONFIG_FILENAME_SYSTEM);
 }
 
+int git_config_find_programdata(git_buf *path)
+{
+	git_buf_sanitize(path);
+	return git_sysdir_find_programdata_file(path, GIT_CONFIG_FILENAME_PROGRAMDATA);
+}
+
 int git_config__global_location(git_buf *buf)
 {
 	const git_buf *paths;
@@ -1133,6 +1139,10 @@ int git_config_open_default(git_config **out)
 		error = git_config_add_file_ondisk(cfg, buf.ptr,
 			GIT_CONFIG_LEVEL_SYSTEM, 0);
 
+	if (!error && !git_config_find_programdata(&buf))
+		error = git_config_add_file_ondisk(cfg, buf.ptr,
+			GIT_CONFIG_LEVEL_PROGRAMDATA, 0);
+
 	git_buf_free(&buf);
 
 	if (error) {
diff --git a/src/config.h b/src/config.h
index ba74533..00c12b5 100644
--- a/src/config.h
+++ b/src/config.h
@@ -12,6 +12,7 @@
 #include "vector.h"
 #include "repository.h"
 
+#define GIT_CONFIG_FILENAME_PROGRAMDATA "config"
 #define GIT_CONFIG_FILENAME_SYSTEM "gitconfig"
 #define GIT_CONFIG_FILENAME_GLOBAL ".gitconfig"
 #define GIT_CONFIG_FILENAME_XDG    "config"
diff --git a/src/repository.c b/src/repository.c
index 77145cf..38d1869 100644
--- a/src/repository.c
+++ b/src/repository.c
@@ -585,7 +585,8 @@ static int load_config(
 	git_repository *repo,
 	const char *global_config_path,
 	const char *xdg_config_path,
-	const char *system_config_path)
+	const char *system_config_path,
+	const char *programdata_path)
 {
 	int error;
 	git_buf config_path = GIT_BUF_INIT;
@@ -626,6 +627,12 @@ static int load_config(
 		error != GIT_ENOTFOUND)
 		goto on_error;
 
+	if (programdata_path != NULL &&
+		(error = git_config_add_file_ondisk(
+			cfg, programdata_path, GIT_CONFIG_LEVEL_PROGRAMDATA, 0)) < 0 &&
+		error != GIT_ENOTFOUND)
+		goto on_error;
+
 	giterr_clear(); /* clear any lingering ENOTFOUND errors */
 
 	*out = cfg;
@@ -651,11 +658,13 @@ int git_repository_config__weakptr(git_config **out, git_repository *repo)
 		git_buf global_buf = GIT_BUF_INIT;
 		git_buf xdg_buf = GIT_BUF_INIT;
 		git_buf system_buf = GIT_BUF_INIT;
+		git_buf programdata_buf = GIT_BUF_INIT;
 		git_config *config;
 
 		git_config_find_global(&global_buf);
 		git_config_find_xdg(&xdg_buf);
 		git_config_find_system(&system_buf);
+		git_config_find_programdata(&programdata_buf);
 
 		/* If there is no global file, open a backend for it anyway */
 		if (git_buf_len(&global_buf) == 0)
@@ -665,7 +674,8 @@ int git_repository_config__weakptr(git_config **out, git_repository *repo)
 			&config, repo,
 			path_unless_empty(&global_buf),
 			path_unless_empty(&xdg_buf),
-			path_unless_empty(&system_buf));
+			path_unless_empty(&system_buf),
+			path_unless_empty(&programdata_buf));
 		if (!error) {
 			GIT_REFCOUNT_OWN(config, repo);
 
diff --git a/src/sysdir.c b/src/sysdir.c
index 2795de4..bf53d83 100644
--- a/src/sysdir.c
+++ b/src/sysdir.c
@@ -15,6 +15,16 @@
 #include "win32/findfile.h"
 #endif
 
+static int git_sysdir_guess_programdata_dirs(git_buf *out)
+{
+#ifdef GIT_WIN32
+	return git_win32__find_programdata_dirs(out);
+#else
+	git_buf_clear(out);
+	return 0;
+#endif
+}
+
 static int git_sysdir_guess_system_dirs(git_buf *out)
 {
 #ifdef GIT_WIN32
@@ -76,12 +86,13 @@ static int git_sysdir_guess_template_dirs(git_buf *out)
 typedef int (*git_sysdir_guess_cb)(git_buf *out);
 
 static git_buf git_sysdir__dirs[GIT_SYSDIR__MAX] =
-	{ GIT_BUF_INIT, GIT_BUF_INIT, GIT_BUF_INIT, GIT_BUF_INIT };
+	{ GIT_BUF_INIT, GIT_BUF_INIT, GIT_BUF_INIT, GIT_BUF_INIT, GIT_BUF_INIT };
 
 static git_sysdir_guess_cb git_sysdir__dir_guess[GIT_SYSDIR__MAX] = {
 	git_sysdir_guess_system_dirs,
 	git_sysdir_guess_global_dirs,
 	git_sysdir_guess_xdg_dirs,
+	git_sysdir_guess_programdata_dirs,
 	git_sysdir_guess_template_dirs,
 };
 
@@ -258,6 +269,12 @@ int git_sysdir_find_xdg_file(git_buf *path, const char *filename)
 		path, filename, GIT_SYSDIR_XDG, "global/xdg");
 }
 
+int git_sysdir_find_programdata_file(git_buf *path, const char *filename)
+{
+	return git_sysdir_find_in_dirlist(
+		path, filename, GIT_SYSDIR_PROGRAMDATA, "ProgramData");
+}
+
 int git_sysdir_find_template_dir(git_buf *path)
 {
 	return git_sysdir_find_in_dirlist(
diff --git a/src/sysdir.h b/src/sysdir.h
index f1bbf0b..12874fc 100644
--- a/src/sysdir.h
+++ b/src/sysdir.h
@@ -39,6 +39,15 @@ extern int git_sysdir_find_xdg_file(git_buf *path, const char *filename);
 extern int git_sysdir_find_system_file(git_buf *path, const char *filename);
 
 /**
+ * Find a "ProgramData" file (i.e. one in %PROGRAMDATA%)
+ *
+ * @param path buffer to write the full path into
+ * @param filename name of file to find in the ProgramData directory
+ * @return 0 if found, GIT_ENOTFOUND if not found, or -1 on other OS error
+ */
+extern int git_sysdir_find_programdata_file(git_buf *path, const char *filename);
+
+/**
  * Find template directory.
  *
  * @param path buffer to write the full path into
@@ -50,8 +59,9 @@ typedef enum {
 	GIT_SYSDIR_SYSTEM = 0,
 	GIT_SYSDIR_GLOBAL = 1,
 	GIT_SYSDIR_XDG    = 2,
-	GIT_SYSDIR_TEMPLATE = 3,
-	GIT_SYSDIR__MAX   = 4,
+	GIT_SYSDIR_PROGRAMDATA = 3,
+	GIT_SYSDIR_TEMPLATE = 4,
+	GIT_SYSDIR__MAX   = 5,
 } git_sysdir_t;
 
 /**
diff --git a/src/win32/findfile.c b/src/win32/findfile.c
index de27dd0..58c2227 100644
--- a/src/win32/findfile.c
+++ b/src/win32/findfile.c
@@ -215,3 +215,13 @@ int git_win32__find_xdg_dirs(git_buf *out)
 
 	return win32_find_existing_dirs(out, global_tmpls);
 }
+
+int git_win32__find_programdata_dirs(git_buf *out)
+{
+	static const wchar_t *programdata_tmpls[2] = {
+		L"%PROGRAMDATA%\\Git",
+		NULL,
+	};
+
+	return win32_find_existing_dirs(out, programdata_tmpls);
+}
diff --git a/src/win32/findfile.h b/src/win32/findfile.h
index a50319b..3d5fff4 100644
--- a/src/win32/findfile.h
+++ b/src/win32/findfile.h
@@ -11,6 +11,7 @@
 extern int git_win32__find_system_dirs(git_buf *out, const wchar_t *subpath);
 extern int git_win32__find_global_dirs(git_buf *out);
 extern int git_win32__find_xdg_dirs(git_buf *out);
+extern int git_win32__find_programdata_dirs(git_buf *out);
 
 #endif
 
diff --git a/tests/config/global.c b/tests/config/global.c
index b5e83fe..1336ef6 100644
--- a/tests/config/global.c
+++ b/tests/config/global.c
@@ -65,3 +65,43 @@ void test_config_global__open_xdg(void)
 	git_config_free(xdg);
 	git_config_free(cfg);
 }
+
+void test_config_global__open_programdata(void)
+{
+	char *programdata;
+	git_config *cfg;
+	git_repository *repo;
+	git_buf config_path = GIT_BUF_INIT;
+	git_buf var_contents = GIT_BUF_INIT;
+
+	if (!cl_getenv("GITTEST_INVASIVE_FS_STRUCTURE"))
+		cl_skip();
+
+	programdata = cl_getenv("PROGRAMDATA");
+	cl_git_pass(git_buf_printf(&config_path, "%s/Git", programdata));
+	cl_git_pass(p_mkdir(config_path.ptr, 0777));
+	cl_git_pass(git_buf_puts(&config_path, "/config"));
+
+	cl_git_pass(git_config_open_ondisk(&cfg, config_path.ptr));
+	cl_git_pass(git_config_set_string(cfg, "programdata.var", "even higher level"));
+
+	git_buf_free(&config_path);
+	git_config_free(cfg);
+
+	git_config_open_default(&cfg);
+	cl_git_pass(git_config_get_string_buf(&var_contents, cfg, "programdata.var"));
+	cl_assert_equal_s("even higher level", var_contents.ptr);
+
+	git_config_free(cfg);
+	git_buf_free(&var_contents);
+
+	cl_git_pass(git_repository_init(&repo, "./foo.git", true));
+	cl_git_pass(git_repository_config(&cfg, repo));
+	cl_git_pass(git_config_get_string_buf(&var_contents, cfg, "programdata.var"));
+	cl_assert_equal_s("even higher level", var_contents.ptr);
+
+	git_config_free(cfg);
+	git_buf_free(&var_contents);
+	git_repository_free(repo);
+	cl_fixture_cleanup("./foo.git");
+}