repository: start recognizing the current state

Recognize when we're merging, reverting or doing a cherry-pick, which
we need if we want to generate message templates for merging et al.

Author: carlosmn

include/git2/repository.h

@@ -302,6 +302,15 @@ GIT_EXTERN(int) git_repository_index(git_index **out, git_repository *repo);
  */
 GIT_EXTERN(void) git_repository_set_index(git_repository *repo, git_index *index);
 
+typedef enum {
+	GIT_REPOSITORY_STATE_NONE,
+	GIT_REPOSITORY_STATE_MERGE,
+	GIT_REPOSITORY_STATE_REVERT,
+	GIT_REPOSITORY_STATE_CHERRY_PICK,
+} git_repository_state_t;
+
+GIT_EXTERN(int) git_repository_state(git_repository *repo);
+
 /** @} */
 GIT_END_DECL
 #endif

src/refs.h

@@ -29,6 +29,8 @@
 #define GIT_HEAD_FILE "HEAD"
 #define GIT_FETCH_HEAD_FILE "FETCH_HEAD"
 #define GIT_MERGE_HEAD_FILE "MERGE_HEAD"
+#define GIT_REVERT_HEAD_FILE "REVERT_HEAD"
+#define GIT_CHERRY_PICK_HEAD_FILE "CHERRY_PICK_HEAD"
 #define GIT_REFS_HEADS_MASTER_FILE GIT_REFS_HEADS_DIR "master"
 
 #define GIT_REFNAME_MAX 1024

src/repository.c

@@ -1058,3 +1058,35 @@ int git_repository_head_tree(git_tree **tree, git_repository *repo)
 	*tree = (git_tree *)obj;
 	return 0;
 }
+
+int git_repository_state(git_repository *repo)
+{
+	git_buf path = GIT_BUF_INIT;
+
+	if (git_buf_joinpath(&path, repo->path_repository, GIT_MERGE_HEAD_FILE) < 0)
+		return -1;
+
+	if (git_path_exists(git_buf_cstr(&path))) {
+		git_buf_free(&path);
+		return GIT_REPOSITORY_STATE_MERGE;
+	}
+
+	if (git_buf_joinpath(&path, repo->path_repository, GIT_REVERT_HEAD_FILE) < 0)
+		return -1;
+
+	if (git_path_exists(git_buf_cstr(&path))) {
+		git_buf_free(&path);
+		return GIT_REPOSITORY_STATE_REVERT;
+	}
+
+	if (git_buf_joinpath(&path, repo->path_repository, GIT_CHERRY_PICK_HEAD_FILE) < 0)
+		return -1;
+
+	if (git_path_exists(git_buf_cstr(&path))) {
+		git_buf_free(&path);
+		return GIT_REPOSITORY_STATE_CHERRY_PICK;
+	}
+
+	git_buf_free(&path);
+	return GIT_REPOSITORY_STATE_NONE;
+}

tests-clar/repo/state.c

@@ -0,0 +1,47 @@
+#include "clar_libgit2.h"
+#include "buffer.h"
+#include "refs.h"
+#include "posix.h"
+
+static git_repository *_repo;
+static git_buf _path;
+
+void test_repo_state__initialize(void)
+{
+	_repo = cl_git_sandbox_init("testrepo.git");
+}
+
+void test_repo_state__cleanup(void)
+{
+	cl_git_sandbox_cleanup();
+	git_buf_free(&_path);
+}
+
+void test_repo_state__none(void)
+{
+	/* The repo should be at its default state */
+	cl_assert_equal_i(GIT_REPOSITORY_STATE_NONE, git_repository_state(_repo));
+}
+
+void test_repo_state__merge(void)
+{
+
+	/* Then it should recognise that .git/MERGE_HEAD and friends mean their respective states */
+	cl_git_pass(git_buf_joinpath(&_path, git_repository_path(_repo), GIT_MERGE_HEAD_FILE));
+	cl_git_mkfile(git_buf_cstr(&_path), "dummy");
+	cl_assert_equal_i(GIT_REPOSITORY_STATE_MERGE, git_repository_state(_repo));
+}
+
+void test_repo_state__revert(void)
+{
+	cl_git_pass(git_buf_joinpath(&_path, git_repository_path(_repo), GIT_REVERT_HEAD_FILE));
+	cl_git_mkfile(git_buf_cstr(&_path), "dummy");
+	cl_assert_equal_i(GIT_REPOSITORY_STATE_REVERT, git_repository_state(_repo));
+}
+
+void test_repo_state__cherry_pick(void)
+{
+	cl_git_pass(git_buf_joinpath(&_path, git_repository_path(_repo), GIT_CHERRY_PICK_HEAD_FILE));
+	cl_git_mkfile(git_buf_cstr(&_path), "dummy");
+	cl_assert_equal_i(GIT_REPOSITORY_STATE_CHERRY_PICK, git_repository_state(_repo));
+}