worktree: implement `git_worktree_validate`

Add a new function that checks wether a given `struct
git_worktree` is valid. The validation includes checking if the
gitdir, parent directory and common directory are present.

2 files changed, 13 insertions, 0 deletions

diff --git a/include/git2/errors.h b/include/git2/errors.h
index e959ffd8a..1d271366f 100644
--- a/include/git2/errors.h
+++ b/include/git2/errors.h
@@ -100,6 +100,7 @@ typedef enum {
 	GITERR_REBASE,
 	GITERR_FILESYSTEM,
 	GITERR_PATCH,
+	GITERR_WORKTREE
 } git_error_t;
 
 /**
diff --git a/include/git2/worktree.h b/include/git2/worktree.h
index 8313265d5..c6ca30bcd 100644
--- a/include/git2/worktree.h
+++ b/include/git2/worktree.h
@@ -49,6 +49,18 @@ GIT_EXTERN(int) git_worktree_lookup(git_worktree **out, git_repository *repo, co
  */
 GIT_EXTERN(void) git_worktree_free(git_worktree *wt);
 
+/**
+ * Check if worktree is valid
+ *
+ * A valid worktree requires both the git data structures inside
+ * the linked parent repository and the linked working copy to be
+ * present.
+ *
+ * @param wt Worktree to check
+ * @return 0 when worktree is valid, error-code otherwise
+ */
+GIT_EXTERN(int) git_worktree_validate(const git_worktree *wt);
+
 /** @} */
 GIT_END_DECL
 #endif