[WIP/RFC 17/23] repo: introduce new repository object

[Brandon Williams <bmwill@google.com>]

Introduce 'struct repo' an object used to represent a repository.

Signed-off-by: Brandon Williams <bmwill@google.com>
---
 Makefile |  1 +
 repo.c   | 42 ++++++++++++++++++++++++++++++++++++++++++
 repo.h   | 15 +++++++++++++++
 3 files changed, 58 insertions(+)
 create mode 100644 repo.c
 create mode 100644 repo.h

diff --git a/Makefile b/Makefile
index e35542e63..a49d2f96a 100644
--- a/Makefile
+++ b/Makefile
@@ -821,6 +821,7 @@ LIB_OBJS += refs/ref-cache.o
 LIB_OBJS += ref-filter.o
 LIB_OBJS += remote.o
 LIB_OBJS += replace_object.o
+LIB_OBJS += repo.o
 LIB_OBJS += rerere.o
 LIB_OBJS += resolve-undo.o
 LIB_OBJS += revision.o
diff --git a/repo.c b/repo.c
new file mode 100644
index 000000000..d47e98d95
--- /dev/null
+++ b/repo.c
@@ -0,0 +1,42 @@
+#include "cache.h"
+#include "repo.h"
+
+int
+repo_init(struct repo *repo, const char *gitdir, const char *worktree)
+{
+	int error = 0;
+	char *abspath = real_pathdup(gitdir, 1);
+	char *suspect = xstrfmt("%s/.git", abspath);
+	const char *resolved_gitdir;
+
+	memset(repo, 0, sizeof(struct repo));
+
+	/* First assume 'gitdir' references the gitdir directly */
+	resolved_gitdir = resolve_gitdir_gently(abspath, &error);
+	/* otherwise; try 'gitdir'.git */
+	if (!resolved_gitdir) {
+		resolved_gitdir = resolve_gitdir_gently(suspect, &error);
+		if (!resolved_gitdir) {
+			die("'%s' is not a repository\n", abspath);
+			return error;
+		}
+	}
+
+	repo->gitdir = xstrdup(resolved_gitdir);
+	/* Maybe need a check to verify that a worktree is indeed a worktree? */
+	repo->worktree = xstrdup_or_null(worktree);
+
+	free(abspath);
+	free(suspect);
+
+	return error;
+}
+
+void
+repo_clear(struct repo *repo)
+{
+	free(repo->gitdir);
+	repo->gitdir = NULL;
+	free(repo->worktree);
+	repo->worktree = NULL;
+}
diff --git a/repo.h b/repo.h
new file mode 100644
index 000000000..55f2dbec6
--- /dev/null
+++ b/repo.h
@@ -0,0 +1,15 @@
+#ifndef REPO_H
+#define REPO_H
+
+struct index_state;
+
+struct repo {
+	char *gitdir;
+	char *worktree;
+	const char *submodule_prefix;
+};
+
+extern int repo_init(struct repo *repo, const char *gitdir, const char *worktree);
+extern void repo_clear(struct repo *repo);
+
+#endif /* REPO_H */
-- 
2.13.0.303.g4ebf302169-goog