Move config to a backend structure

Configuration options can come from different sources. Currently,
there is only support for reading them from a flat file, but it might
make sense to read it from a database at some point.

Move the parsing code into src/config_file.c and create an include
file include/git2/config_backend.h to allow for other backends to be
developed.

Signed-off-by: Carlos Martín Nieto <cmn@elego.de>

3 files changed, 71 insertions, 1 deletions

diff --git a/include/git2/config.h b/include/git2/config.h
index abf59fa9e..3ebbe64de 100644
--- a/include/git2/config.h
+++ b/include/git2/config.h
@@ -38,12 +38,22 @@
 GIT_BEGIN_DECL
 
 /**
+ * Allocate a new configuration
+ */
+GIT_EXTERN(int) git_config_new(git_config **out);
+
+/**
  * Open a configuration file
  *
  * @param cfg_out pointer to the configuration data
  * @param path where to load the confiration from
  */
-GIT_EXTERN(int) git_config_open(git_config **cfg_out, const char *path);
+GIT_EXTERN(int) git_config_open_bare(git_config **cfg_out, const char *path);
+
+/**
+ *
+ */
+GIT_EXTERN(int) git_config_add_backend(git_config *cfg, git_config_backend *backend, int priority);
 
 /**
  * Free the configuration and its associated memory
diff --git a/include/git2/config_backend.h b/include/git2/config_backend.h
new file mode 100644
index 000000000..427cd95dd
--- /dev/null
+++ b/include/git2/config_backend.h
@@ -0,0 +1,57 @@
+/*
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2,
+ * as published by the Free Software Foundation.
+ *
+ * In addition to the permissions in the GNU General Public License,
+ * the authors give you unlimited permission to link the compiled
+ * version of this file into combinations with other programs,
+ * and to distribute those combinations without any restriction
+ * coming from the use of this file.  (The General Public License
+ * restrictions do apply in other respects; for example, they cover
+ * modification of the file, and distribution when not linked into
+ * a combined executable.)
+ *
+ * This file is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef INCLUDE_git_config_backend_h__
+#define INCLUDE_git_config_backend_h__
+
+#include "common.h"
+#include "types.h"
+#include "config.h"
+
+GIT_BEGIN_DECL
+
+struct git_config;
+
+struct git_config_backend {
+	struct git_config *cfg;
+	/* Open means open the file/database and parse if necessary */
+	int (*open)(struct git_config_backend *);
+	int (* get)(struct git_config_backend *, const char *key, const char **value);
+	int (* set)(struct git_config_backend *, const char *key, const char *value);
+	int (*foreach)(struct git_config_backend *, int (*fn)(const char *, void *), void *data);
+	void (*free)(struct git_config_backend *);
+};
+
+/**
+ * Create a file-backed configuration backend
+ *
+ * @param out the new backend
+ * @path where the config file is located
+ */
+GIT_EXTERN(int) git_config_backend_file(struct git_config_backend **out, const char *path);
+
+GIT_END_DECL
+
+#endif
diff --git a/include/git2/types.h b/include/git2/types.h
index 84e3d5b7f..49e80dd95 100644
--- a/include/git2/types.h
+++ b/include/git2/types.h
@@ -133,6 +133,9 @@ typedef struct git_index git_index;
 /** Memory representation of a config file */
 typedef struct git_config git_config;
 
+/** A specific implementation of a config backend */
+typedef struct git_config_backend git_config_backend;
+
 /** Memory representation of a config variable */
 typedef struct git_cvar git_cvar;