apply: introduce `git_apply`

Introduce `git_apply`, which will take a `git_diff` and apply it to the
working directory (akin to `git apply`), the index (akin to `git apply
--cached`), or both (akin to `git apply --index`).

1 files changed, 42 insertions, 0 deletions

diff --git a/include/git2/apply.h b/include/git2/apply.h
index a4ec4fc08..3bf6aad63 100644
--- a/include/git2/apply.h
+++ b/include/git2/apply.h
@@ -36,6 +36,48 @@ GIT_EXTERN(int) git_apply_to_tree(
 	git_tree *preimage,
 	git_diff *diff);
 
+typedef enum {
+	/**
+	 * Apply the patch to the workdir, leaving the index untouched.
+	 * This is the equivalent of `git apply` with no location argument.
+	 */
+	GIT_APPLY_LOCATION_WORKDIR = 0,
+
+	/**
+	 * Apply the patch to the index, leaving the working directory
+	 * untouched.  This is the equivalent of `git apply --cached`.
+	 */
+	GIT_APPLY_LOCATION_INDEX = 1,
+
+	/**
+	 * Apply the patch to both the working directory and the index.
+	 * This is the equivalent of `git apply --index`.
+	 */
+	GIT_APPLY_LOCATION_BOTH = 2,
+} git_apply_location_t;
+
+typedef struct {
+	unsigned int version;
+
+	git_apply_location_t location;
+} git_apply_options;
+
+#define GIT_APPLY_OPTIONS_VERSION 1
+#define GIT_APPLY_OPTIONS_INIT {GIT_APPLY_OPTIONS_VERSION}
+
+/**
+ * Apply a `git_diff` to the given repository, making changes directly
+ * in the working directory, the index, or both.
+ *
+ * @param repo the repository to apply to
+ * @param diff the diff to apply
+ * @param options the options for the apply (or null for defaults)
+ */
+GIT_EXTERN(int) git_apply(
+	git_repository *repo,
+	git_diff *diff,
+	git_apply_options *options);
+
 /** @} */
 GIT_END_DECL
 #endif