Merge pull request #3436 from pks-t/libgit2-worktree

Worktree implementation

5 files changed, 268 insertions, 0 deletions

diff --git a/include/git2/branch.h b/include/git2/branch.h
index 34354f4e5..88fe723a0 100644
--- a/include/git2/branch.h
+++ b/include/git2/branch.h
@@ -246,6 +246,18 @@ GIT_EXTERN(int) git_branch_is_head(
 	const git_reference *branch);
 
 /**
+ * Determine if the current branch is checked out in any linked
+ * repository.
+ *
+ * @param branch Reference to the branch.
+ *
+ * @return 1 if branch is checked out, 0 if it isn't,
+ * error code otherwise.
+ */
+GIT_EXTERN(int) git_branch_is_checked_out(
+	const git_reference *branch);
+
+/**
  * Return the name of remote that the remote tracking branch belongs to.
  *
  * @param out Pointer to the user-allocated git_buf which will be filled with the name of the remote.
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/repository.h b/include/git2/repository.h
index 3d70d1b89..a396a5409 100644
--- a/include/git2/repository.h
+++ b/include/git2/repository.h
@@ -35,6 +35,17 @@ GIT_BEGIN_DECL
  * @return 0 or an error code
  */
 GIT_EXTERN(int) git_repository_open(git_repository **out, const char *path);
+/**
+ * Open working tree as a repository
+ *
+ * Open the working directory of the working tree as a normal
+ * repository that can then be worked on.
+ *
+ * @param out Output pointer containing opened repository
+ * @param wt Working tree to open
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_repository_open_from_worktree(git_repository **out, git_worktree *wt);
 
 /**
  * Create a "fake" repository to wrap an object database
@@ -335,6 +346,17 @@ GIT_EXTERN(int) git_repository_init_ext(
 GIT_EXTERN(int) git_repository_head(git_reference **out, git_repository *repo);
 
 /**
+ * Retrieve the referenced HEAD for the worktree
+ *
+ * @param out pointer to the reference which will be retrieved
+ * @param repo a repository object
+ * @param name name of the worktree to retrieve HEAD for
+ * @return 0 when successful, error-code otherwise
+ */
+GIT_EXTERN(int) git_repository_head_for_worktree(git_reference **out, git_repository *repo,
+	const char *name);
+
+/**
  * Check if a repository's HEAD is detached
  *
  * A repository's HEAD is detached when it points directly to a commit
@@ -346,6 +368,20 @@ GIT_EXTERN(int) git_repository_head(git_reference **out, git_repository *repo);
  */
 GIT_EXTERN(int) git_repository_head_detached(git_repository *repo);
 
+/*
+ * Check if a worktree's HEAD is detached
+ *
+ * A worktree's HEAD is detached when it points directly to a
+ * commit instead of a branch.
+ *
+ * @param repo a repository object
+ * @param name name of the worktree to retrieve HEAD for
+ * @return 1 if HEAD is detached, 0 if its not; error code if
+ *  there was an error
+ */
+GIT_EXTERN(int) git_repository_head_detached_for_worktree(git_repository *repo,
+	const char *name);
+
 /**
  * Check if the current branch is unborn
  *
@@ -371,6 +407,42 @@ GIT_EXTERN(int) git_repository_head_unborn(git_repository *repo);
 GIT_EXTERN(int) git_repository_is_empty(git_repository *repo);
 
 /**
+ * List of items which belong to the git repository layout
+ */
+typedef enum {
+	GIT_REPOSITORY_ITEM_GITDIR,
+	GIT_REPOSITORY_ITEM_WORKDIR,
+	GIT_REPOSITORY_ITEM_COMMONDIR,
+	GIT_REPOSITORY_ITEM_INDEX,
+	GIT_REPOSITORY_ITEM_OBJECTS,
+	GIT_REPOSITORY_ITEM_REFS,
+	GIT_REPOSITORY_ITEM_PACKED_REFS,
+	GIT_REPOSITORY_ITEM_REMOTES,
+	GIT_REPOSITORY_ITEM_CONFIG,
+	GIT_REPOSITORY_ITEM_INFO,
+	GIT_REPOSITORY_ITEM_HOOKS,
+	GIT_REPOSITORY_ITEM_LOGS,
+	GIT_REPOSITORY_ITEM_MODULES,
+	GIT_REPOSITORY_ITEM_WORKTREES
+} git_repository_item_t;
+
+/**
+ * Get the location of a specific repository file or directory
+ *
+ * This function will retrieve the path of a specific repository
+ * item. It will thereby honor things like the repository's
+ * common directory, gitdir, etc. In case a file path cannot
+ * exist for a given item (e.g. the working directory of a bare
+ * repository), an error is returned.
+ *
+ * @param out Buffer to store the path at
+ * @param repo Repository to get path for
+ * @param item The repository item for which to retrieve the path
+ * @return 0 on success, otherwise a negative value
+ */
+GIT_EXTERN(int) git_repository_item_path(git_buf *out, git_repository *repo, git_repository_item_t item);
+
+/**
  * Get the path of this repository
  *
  * This is the path of the `.git` folder for normal repositories,
@@ -393,6 +465,17 @@ GIT_EXTERN(const char *) git_repository_path(git_repository *repo);
 GIT_EXTERN(const char *) git_repository_workdir(git_repository *repo);
 
 /**
+ * Get the path of the shared common directory for this repository
+ *
+ * If the repository is bare is not a worktree, the git directory
+ * path is returned.
+ *
+ * @param repo A repository object
+ * @return the path to the common dir
+ */
+GIT_EXTERN(const char *) git_repository_commondir(git_repository *repo);
+
+/**
  * Set the path to the working directory for this repository
  *
  * The working directory doesn't need to be the same one
@@ -421,6 +504,14 @@ GIT_EXTERN(int) git_repository_set_workdir(
 GIT_EXTERN(int) git_repository_is_bare(git_repository *repo);
 
 /**
+ * Check if a repository is a linked work tree
+ *
+ * @param repo Repo to test
+ * @return 1 if the repository is a linked work tree, 0 otherwise.
+ */
+GIT_EXTERN(int) git_repository_is_worktree(git_repository *repo);
+
+/**
  * Get the configuration file for this repository.
  *
  * If a configuration file has not been set, the default
diff --git a/include/git2/types.h b/include/git2/types.h
index 6f41014b3..dfdaa2920 100644
--- a/include/git2/types.h
+++ b/include/git2/types.h
@@ -104,6 +104,9 @@ typedef struct git_refdb_backend git_refdb_backend;
  */
 typedef struct git_repository git_repository;
 
+/** Representation of a working tree */
+typedef struct git_worktree git_worktree;
+
 /** Representation of a generic object in a repository */
 typedef struct git_object git_object;
 
diff --git a/include/git2/worktree.h b/include/git2/worktree.h
new file mode 100644
index 000000000..cad1284fa
--- /dev/null
+++ b/include/git2/worktree.h
@@ -0,0 +1,161 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_git_worktree_h__
+#define INCLUDE_git_worktree_h__
+
+#include "common.h"
+#include "buffer.h"
+#include "types.h"
+#include "strarray.h"
+
+/**
+ * @file git2/worktrees.h
+ * @brief Git worktree related functions
+ * @defgroup git_commit Git worktree related functions
+ * @ingroup Git
+ * @{
+ */
+GIT_BEGIN_DECL
+
+/**
+ * List names of linked working trees
+ *
+ * The returned list should be released with `git_strarray_free`
+ * when no longer needed.
+ *
+ * @param out pointer to the array of working tree names
+ * @param repo the repo to use when listing working trees
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_worktree_list(git_strarray *out, git_repository *repo);
+
+/**
+ * Lookup a working tree by its name for a given repository
+ *
+ * @param out Output pointer to looked up worktree or `NULL`
+ * @param repo The repository containing worktrees
+ * @param name Name of the working tree to look up
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_worktree_lookup(git_worktree **out, git_repository *repo, const char *name);
+
+/**
+ * Free a previously allocated worktree
+ *
+ * @param wt worktree handle to close. If NULL nothing occurs.
+ */
+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);
+
+/**
+ * Add a new working tree
+ *
+ * Add a new working tree for the repository, that is create the
+ * required data structures inside the repository and check out
+ * the current HEAD at `path`
+ *
+ * @param out Output pointer containing new working tree
+ * @param repo Repository to create working tree for
+ * @param name Name of the working tree
+ * @param path Path to create working tree at
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_worktree_add(git_worktree **out, git_repository *repo, const char *name, const char *path);
+
+/**
+ * Lock worktree if not already locked
+ *
+ * Lock a worktree, optionally specifying a reason why the linked
+ * working tree is being locked.
+ *
+ * @param wt Worktree to lock
+ * @param reason Reason why the working tree is being locked
+ * @return 0 on success, non-zero otherwise
+ */
+GIT_EXTERN(int) git_worktree_lock(git_worktree *wt, char *reason);
+
+/**
+ * Unlock a locked worktree
+ *
+ * @param wt Worktree to unlock
+ * @return 0 on success, 1 if worktree was not locked, error-code
+ *  otherwise
+ */
+GIT_EXTERN(int) git_worktree_unlock(git_worktree *wt);
+
+/**
+ * Check if worktree is locked
+ *
+ * A worktree may be locked if the linked working tree is stored
+ * on a portable device which is not available.
+ *
+ * @param reason Buffer to store reason in. If NULL no reason is stored.
+ * @param wt Worktree to check
+ * @return 0 when the working tree not locked, a value greater
+ *  than zero if it is locked, less than zero if there was an
+ *  error
+ */
+GIT_EXTERN(int) git_worktree_is_locked(git_buf *reason, const git_worktree *wt);
+
+/**
+ * Flags which can be passed to git_worktree_prune to alter its
+ * behavior.
+ */
+typedef enum {
+	/* Prune working tree even if working tree is valid */
+	GIT_WORKTREE_PRUNE_VALID = 1u << 0,
+	/* Prune working tree even if it is locked */
+	GIT_WORKTREE_PRUNE_LOCKED = 1u << 1,
+	/* Prune checked out working tree */
+	GIT_WORKTREE_PRUNE_WORKING_TREE = 1u << 2,
+} git_worktree_prune_t;
+
+/**
+ * Is the worktree prunable with the given set of flags?
+ *
+ * A worktree is not prunable in the following scenarios:
+ *
+ * - the worktree is linking to a valid on-disk worktree. The
+ *   GIT_WORKTREE_PRUNE_VALID flag will cause this check to be
+ *   ignored.
+ * - the worktree is not valid but locked. The
+ *   GIT_WORKRTEE_PRUNE_LOCKED flag will cause this check to be
+ *   ignored.
+ *
+ * If the worktree is not valid and not locked or if the above
+ * flags have been passed in, this function will return a
+ * positive value.
+ */
+GIT_EXTERN(int) git_worktree_is_prunable(git_worktree *wt, unsigned flags);
+
+/**
+ * Prune working tree
+ *
+ * Prune the working tree, that is remove the git data
+ * structures on disk. The repository will only be pruned of
+ * `git_worktree_is_prunable` succeeds.
+ *
+ * @param wt Worktree to prune
+ * @param flags git_worktree_prune_t flags
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_worktree_prune(git_worktree *wt, unsigned flags);
+
+/** @} */
+GIT_END_DECL
+#endif