text: /*
   * 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.
   */
  
  #include <assert.h>
  
  #include "checkout.h"
  
  #include "git2/repository.h"
  #include "git2/refs.h"
  #include "git2/tree.h"
  #include "git2/blob.h"
  #include "git2/config.h"
  #include "git2/diff.h"
  #include "git2/submodule.h"
  #include "git2/sys/index.h"
  
  #include "refs.h"
  #include "repository.h"
  #include "index.h"
  #include "filter.h"
  #include "blob.h"
  #include "diff.h"
  #include "pathspec.h"
  #include "buf_text.h"
  #include "merge_file.h"
  #include "path.h"
  
  /* See docs/checkout-internals.md for more information */
  
  enum {
  	CHECKOUT_ACTION__NONE = 0,
  	CHECKOUT_ACTION__REMOVE = 1,
  	CHECKOUT_ACTION__UPDATE_BLOB = 2,
  	CHECKOUT_ACTION__UPDATE_SUBMODULE = 4,
  	CHECKOUT_ACTION__CONFLICT = 8,
  	CHECKOUT_ACTION__REMOVE_CONFLICT = 16,
  	CHECKOUT_ACTION__UPDATE_CONFLICT = 32,
  	CHECKOUT_ACTION__MAX = 32,
  	CHECKOUT_ACTION__DEFER_REMOVE = 64,
  	CHECKOUT_ACTION__REMOVE_AND_UPDATE =
  		(CHECKOUT_ACTION__UPDATE_BLOB | CHECKOUT_ACTION__REMOVE),
  };
  
  typedef struct {
  	git_repository *repo;
  	git_iterator *target;
  	git_diff *diff;
  	git_checkout_options opts;
  	bool opts_free_baseline;
  	char *pfx;
  	git_index *index;
  	git_pool pool;
  	git_vector removes;
  	git_vector remove_conflicts;
  	git_vector update_conflicts;
  	git_vector *update_reuc;
  	git_vector *update_names;
  	git_buf path;
  	size_t workdir_len;
  	git_buf tmp;
  	unsigned int strategy;
  	int can_symlink;
  	bool reload_submodules;
  	size_t total_steps;
  	size_t completed_steps;
  } checkout_data;
  
  typedef struct {
  	const git_index_entry *ancestor;
  	const git_index_entry *ours;
  	const git_index_entry *theirs;
  
  	int name_collision:1,
  		directoryfile:1,
  		one_to_two:1,
  		binary:1,
  		submodule:1;
  } checkout_conflictdata;
  
  static int checkout_notify(
  	checkout_data *data,
  	git_checkout_notify_t why,
  	const git_diff_delta *delta,
  	const git_index_entry *wditem)
  {
  	git_diff_file wdfile;
  	const git_diff_file *baseline = NULL, *target = NULL, *workdir = NULL;
  	const char *path = NULL;
  
  	if (!data->opts.notify_cb ||
  		(why & data->opts.notify_flags) == 0)
  		return 0;
  
  	if (wditem) {
  		memset(&wdfile, 0, sizeof(wdfile));
  
  		git_oid_cpy(&wdfile.id, &wditem->id);
  		wdfile.path = wditem->path;
  		wdfile.size = wditem->file_size;
  		wdfile.flags = GIT_DIFF_FLAG_VALID_ID;
  		wdfile.mode = wditem->mode;
  
  		workdir = &wdfile;
  
  		path = wditem->path;
  	}
  
  	if (delta) {
  		switch (delta->status) {
  		case GIT_DELTA_UNMODIFIED:
  		case GIT_DELTA_MODIFIED:
  		case GIT_DELTA_TYPECHANGE:
  		default:
  			baseline = &delta->old_file;
  			target = &delta->new_file;
  			break;
  		case GIT_DELTA_ADDED:
  		case GIT_DELTA_IGNORED:
  		case GIT_DELTA_UNTRACKED:
  		case GIT_DELTA_UNREADABLE:
  			target = &delta->new_file;
  			break;
  		case GIT_DELTA_DELETED:
  			baseline = &delta->old_file;
  			break;
  		}
  
  		path = delta->old_file.path;
  	}
  
  	{
  		int error = data->opts.notify_cb(
  			why, path, baseline, target, workdir, data->opts.notify_payload);
  
  		return giterr_set_after_callback_function(
  			error, "git_checkout notification");
  	}
  }
  
  static bool checkout_is_workdir_modified(
  	checkout_data *data,
  	const git_diff_file *baseitem,
  	const git_diff_file *newitem,
  	const git_index_entry *wditem)
  {
  	git_oid oid;
  	const git_index_entry *ie;
  
  	/* handle "modified" submodule */
  	if (wditem->mode == GIT_FILEMODE_COMMIT) {
  		git_submodule *sm;
  		unsigned int sm_status = 0;
  		const git_oid *sm_oid = NULL;
  		bool rval = false;
  
  		if (git_submodule_lookup(&sm, data->repo, wditem->path) < 0) {
  			giterr_clear();
  			return true;
  		}
  
  		if (git_submodule_status(&sm_status, sm) < 0 ||
  			GIT_SUBMODULE_STATUS_IS_WD_DIRTY(sm_status))
  			rval = true;
  		else if ((sm_oid = git_submodule_wd_id(sm)) == NULL)
  			rval = false;
  		else
  			rval = (git_oid__cmp(&baseitem->id, sm_oid) != 0);
  
  		git_submodule_free(sm);
  		return rval;
  	}
  
  	/* Look at the cache to decide if the workdir is modified.  If not,
  	 * we can simply compare the oid in the cache to the baseitem instead
  	 * of hashing the file.  If so, we allow the checkout to proceed if the
  	 * oid is identical (ie, the staged item is what we're trying to check
  	 * out.)
  	 */
  	if ((ie = git_index_get_bypath(data->index, wditem->path, 0)) != NULL) {
  		if (wditem->mtime.seconds == ie->mtime.seconds &&
  			wditem->mtime.nanoseconds == ie->mtime.nanoseconds &&
  			wditem->file_size == ie->file_size)
  			return (git_oid__cmp(&baseitem->id, &ie->id) != 0 &&
  				git_oid_cmp(&newitem->id, &ie->id) != 0);
  	}
  
  	/* depending on where base is coming from, we may or may not know
  	 * the actual size of the data, so we can't rely on this shortcut.
  	 */
  	if (baseitem->size && wditem->file_size != baseitem->size)
  		return true;
  
  	if (git_diff__oid_for_entry(&oid, data->diff, wditem, NULL) < 0)
  		return false;
  
  	return (git_oid__cmp(&baseitem->id, &oid) != 0);
  }
  
  #define CHECKOUT_ACTION_IF(FLAG,YES,NO) \
  	((data->strategy & GIT_CHECKOUT_##FLAG) ? CHECKOUT_ACTION__##YES : CHECKOUT_ACTION__##NO)
  
  static int checkout_action_common(
  	int *action,
  	checkout_data *data,
  	const git_diff_delta *delta,
  	const git_index_entry *wd)
  {
  	git_checkout_notify_t notify = GIT_CHECKOUT_NOTIFY_NONE;
  
  	if ((data->strategy & GIT_CHECKOUT_UPDATE_ONLY) != 0)
  		*action = (*action & ~CHECKOUT_ACTION__REMOVE);
  
  	if ((*action & CHECKOUT_ACTION__UPDATE_BLOB) != 0) {
  		if (S_ISGITLINK(delta->new_file.mode))
  			*action = (*action & ~CHECKOUT_ACTION__UPDATE_BLOB) |
  				CHECKOUT_ACTION__UPDATE_SUBMODULE;
  
  		/* to "update" a symlink, we must remove the old one first */
  		if (delta->new_file.mode == GIT_FILEMODE_LINK && wd != NULL)
  			*action |= CHECKOUT_ACTION__REMOVE;
  
  		notify = GIT_CHECKOUT_NOTIFY_UPDATED;
  	}
  
  	if ((*action & CHECKOUT_ACTION__CONFLICT) != 0)
  		notify = GIT_CHECKOUT_NOTIFY_CONFLICT;
  
  	return checkout_notify(data, notify, delta, wd);
  }
  
  static int checkout_action_no_wd(
  	int *action,
  	checkout_data *data,
  	const git_diff_delta *delta)
  {
  	int error = 0;
  
  	*action = CHECKOUT_ACTION__NONE;
  
  	switch (delta->status) {
  	case GIT_DELTA_UNMODIFIED: /* case 12 */
  		error = checkout_notify(data, GIT_CHECKOUT_NOTIFY_DIRTY, delta, NULL);
  		if (error)
  			return error;
  		*action = CHECKOUT_ACTION_IF(SAFE_CREATE, UPDATE_BLOB, NONE);
  		break;
  	case GIT_DELTA_ADDED:    /* case 2 or 28 (and 5 but not really) */
  		*action = CHECKOUT_ACTION_IF(SAFE, UPDATE_BLOB, NONE);
  		break;
  	case GIT_DELTA_MODIFIED: /* case 13 (and 35 but not really) */
  		*action = CHECKOUT_ACTION_IF(SAFE_CREATE, UPDATE_BLOB, CONFLICT);
  		break;
  	case GIT_DELTA_TYPECHANGE: /* case 21 (B->T) and 28 (T->B)*/
  		if (delta->new_file.mode == GIT_FILEMODE_TREE)
  			*action = CHECKOUT_ACTION_IF(SAFE, UPDATE_BLOB, NONE);
  		break;
  	case GIT_DELTA_DELETED: /* case 8 or 25 */
  		*action = CHECKOUT_ACTION_IF(SAFE, REMOVE, NONE);
  		break;
  	default: /* impossible */
  		break;
  	}
  
  	return checkout_action_common(action, data, delta, NULL);
  }
  
  static bool wd_item_is_removable(git_iterator *iter, const git_index_entry *wd)
  {
  	git_buf *full = NULL;
  
  	if (wd->mode != GIT_FILEMODE_TREE)
  		return true;
  	if (git_iterator_current_workdir_path(&full, iter) < 0)
  		return true;
  	return !full || !git_path_contains(full, DOT_GIT);
  }
  
  static int checkout_queue_remove(checkout_data *data, const char *path)
  {
  	char *copy = git_pool_strdup(&data->pool, path);
  	GITERR_CHECK_ALLOC(copy);
  	return git_vector_insert(&data->removes, copy);
  }
  
  /* note that this advances the iterator over the wd item */
  static int checkout_action_wd_only(
  	checkout_data *data,
  	git_iterator *workdir,
  	const git_index_entry **wditem,
  	git_vector *pathspec)
  {
  	int error = 0;
  	bool remove = false;
  	git_checkout_notify_t notify = GIT_CHECKOUT_NOTIFY_NONE;
  	const git_index_entry *wd = *wditem;
  
  	if (!git_pathspec__match(
  			pathspec, wd->path,
  			(data->strategy & GIT_CHECKOUT_DISABLE_PATHSPEC_MATCH) != 0,
  			git_iterator_ignore_case(workdir), NULL, NULL))
  		return git_iterator_advance(wditem, workdir);
  
  	/* check if item is tracked in the index but not in the checkout diff */
  	if (data->index != NULL) {
  		size_t pos;
  
  		error = git_index__find_pos(
  			&pos, data->index, wd->path, 0, GIT_INDEX_STAGE_ANY);
  
  		if (wd->mode != GIT_FILEMODE_TREE) {
  			if (!error) { /* found by git_index__find_pos call */
  				notify = GIT_CHECKOUT_NOTIFY_DIRTY;
  				remove = ((data->strategy & GIT_CHECKOUT_FORCE) != 0);
  			} else if (error != GIT_ENOTFOUND)
  				return error;
  			else
  				error = 0; /* git_index__find_pos does not set error msg */
  		} else {
  			/* for tree entries, we have to see if there are any index
  			 * entries that are contained inside that tree
  			 */
  			const git_index_entry *e = git_index_get_byindex(data->index, pos);
  
  			if (e != NULL && data->diff->pfxcomp(e->path, wd->path) == 0) {
  				notify = GIT_CHECKOUT_NOTIFY_DIRTY;
  				remove = ((data->strategy & GIT_CHECKOUT_FORCE) != 0);
  			}
  		}
  	}
  
  	if (notify != GIT_CHECKOUT_NOTIFY_NONE) {
  		/* if we found something in the index, notify and advance */
  		if ((error = checkout_notify(data, notify, NULL, wd)) != 0)
  			return error;
  
  		if (remove && wd_item_is_removable(workdir, wd))
  			error = checkout_queue_remove(data, wd->path);
  
  		if (!error)
  			error = git_iterator_advance(wditem, workdir);
  	} else {
  		/* untracked or ignored - can't know which until we advance through */
  		bool over = false, removable = wd_item_is_removable(workdir, wd);
  		git_iterator_status_t untracked_state;
  
  		/* copy the entry for issuing notification callback later */
  		git_index_entry saved_wd = *wd;
  		git_buf_sets(&data->tmp, wd->path);
  		saved_wd.path = data->tmp.ptr;
  
  		error = git_iterator_advance_over_with_status(
  			wditem, &untracked_state, workdir);
  		if (error == GIT_ITEROVER)
  			over = true;
  		else if (error < 0)
  			return error;
  
  		if (untracked_state == GIT_ITERATOR_STATUS_IGNORED) {
  			notify = GIT_CHECKOUT_NOTIFY_IGNORED;
  			remove = ((data->strategy & GIT_CHECKOUT_REMOVE_IGNORED) != 0);
  		} else {
  			notify = GIT_CHECKOUT_NOTIFY_UNTRACKED;
  			remove = ((data->strategy & GIT_CHECKOUT_REMOVE_UNTRACKED) != 0);
  		}
  
  		if ((error = checkout_notify(data, notify, NULL, &saved_wd)) != 0)
  			return error;
  
  		if (remove && removable)
  			error = checkout_queue_remove(data, saved_wd.path);
  
  		if (!error && over) /* restore ITEROVER if needed */
  			error = GIT_ITEROVER;
  	}
  
  	return error;
  }
  
  static bool submodule_is_config_only(
  	checkout_data *data,
  	const char *path)
  {
  	git_submodule *sm = NULL;
  	unsigned int sm_loc = 0;
  	bool rval = false;
  
  	if (git_submodule_lookup(&sm, data->repo, path) < 0)
  		return true;
  
  	if (git_submodule_location(&sm_loc, sm) < 0 ||
  		sm_loc == GIT_SUBMODULE_STATUS_IN_CONFIG)
  		rval = true;
  
  	git_submodule_free(sm);
  
  	return rval;
  }
  
  static int checkout_action_with_wd(
  	int *action,
  	checkout_data *data,
  	const git_diff_delta *delta,
  	git_iterator *workdir,
  	const git_index_entry *wd)
  {
  	*action = CHECKOUT_ACTION__NONE;
  
  	switch (delta->status) {
  	case GIT_DELTA_UNMODIFIED: /* case 14/15 or 33 */
  		if (checkout_is_workdir_modified(data, &delta->old_file, &delta->new_file, wd)) {
  			GITERR_CHECK_ERROR(
  				checkout_notify(data, GIT_CHECKOUT_NOTIFY_DIRTY, delta, wd) );
  			*action = CHECKOUT_ACTION_IF(FORCE, UPDATE_BLOB, NONE);
  		}
  		break;
  	case GIT_DELTA_ADDED: /* case 3, 4 or 6 */
  		if (git_iterator_current_is_ignored(workdir))
  			*action = CHECKOUT_ACTION_IF(DONT_OVERWRITE_IGNORED, CONFLICT, UPDATE_BLOB);
  		else
  			*action = CHECKOUT_ACTION_IF(FORCE, UPDATE_BLOB, CONFLICT);
  		break;
  	case GIT_DELTA_DELETED: /* case 9 or 10 (or 26 but not really) */
  		if (checkout_is_workdir_modified(data, &delta->old_file, &delta->new_file, wd))
  			*action = CHECKOUT_ACTION_IF(FORCE, REMOVE, CONFLICT);
  		else
  			*action = CHECKOUT_ACTION_IF(SAFE, REMOVE, NONE);
  		break;
  	case GIT_DELTA_MODIFIED: /* case 16, 17, 18 (or 36 but not really) */
  		if (checkout_is_workdir_modified(data, &delta->old_file, &delta->new_file, wd))
  			*action = CHECKOUT_ACTION_IF(FORCE, UPDATE_BLOB, CONFLICT);
  		else
  			*action = CHECKOUT_ACTION_IF(SAFE, UPDATE_BLOB, NONE);
  		break;
  	case GIT_DELTA_TYPECHANGE: /* case 22, 23, 29, 30 */
  		if (delta->old_file.mode == GIT_FILEMODE_TREE) {
  			if (wd->mode == GIT_FILEMODE_TREE)
  				/* either deleting items in old tree will delete the wd dir,
  				 * or we'll get a conflict when we attempt blob update...
  				 */
  				*action = CHECKOUT_ACTION_IF(SAFE, UPDATE_BLOB, NONE);
  			else if (wd->mode == GIT_FILEMODE_COMMIT) {
  				/* workdir is possibly a "phantom" submodule - treat as a
  				 * tree if the only submodule info came from the config
  				 */
  				if (submodule_is_config_only(data, wd->path))
  					*action = CHECKOUT_ACTION_IF(SAFE, UPDATE_BLOB, NONE);
  				else
  					*action = CHECKOUT_ACTION_IF(FORCE, REMOVE_AND_UPDATE, CONFLICT);
  			} else
  				*action = CHECKOUT_ACTION_IF(FORCE, REMOVE, CONFLICT);
  		}
  		else if (checkout_is_workdir_modified(data, &delta->old_file, &delta->new_file, wd))
  			*action = CHECKOUT_ACTION_IF(FORCE, REMOVE_AND_UPDATE, CONFLICT);
  		else
  			*action = CHECKOUT_ACTION_IF(SAFE, REMOVE_AND_UPDATE, NONE);
  
  		/* don't update if the typechange is to a tree */
  		if (delta->new_file.mode == GIT_FILEMODE_TREE)
  			*action = (*action & ~CHECKOUT_ACTION__UPDATE_BLOB);
  		break;
  	default: /* impossible */
  		break;
  	}
  
  	return checkout_action_common(action, data, delta, wd);
  }
  
  static int checkout_action_with_wd_blocker(
  	int *action,
  	checkout_data *data,
  	const git_diff_delta *delta,
  	const git_index_entry *wd)
  {
  	*action = CHECKOUT_ACTION__NONE;
  
  	switch (delta->status) {
  	case GIT_DELTA_UNMODIFIED:
  		/* should show delta as dirty / deleted */
  		GITERR_CHECK_ERROR(
  			checkout_notify(data, GIT_CHECKOUT_NOTIFY_DIRTY, delta, wd) );
  		*action = CHECKOUT_ACTION_IF(FORCE, REMOVE_AND_UPDATE, NONE);
  		break;
  	case GIT_DELTA_ADDED:
  	case GIT_DELTA_MODIFIED:
  		*action = CHECKOUT_ACTION_IF(FORCE, REMOVE_AND_UPDATE, CONFLICT);
  		break;
  	case GIT_DELTA_DELETED:
  		*action = CHECKOUT_ACTION_IF(FORCE, REMOVE, CONFLICT);
  		break;
  	case GIT_DELTA_TYPECHANGE:
  		/* not 100% certain about this... */
  		*action = CHECKOUT_ACTION_IF(FORCE, REMOVE_AND_UPDATE, CONFLICT);
  		break;
  	default: /* impossible */
  		break;
  	}
  
  	return checkout_action_common(action, data, delta, wd);
  }
  
  static int checkout_action_with_wd_dir(
  	int *action,
  	checkout_data *data,
  	const git_diff_delta *delta,
  	git_iterator *workdir,
  	const git_index_entry *wd)
  {
  	*action = CHECKOUT_ACTION__NONE;
  
  	switch (delta->status) {
  	case GIT_DELTA_UNMODIFIED: /* case 19 or 24 (or 34 but not really) */
  		GITERR_CHECK_ERROR(
  			checkout_notify(data, GIT_CHECKOUT_NOTIFY_DIRTY, delta, NULL));
  		GITERR_CHECK_ERROR(
  			checkout_notify(data, GIT_CHECKOUT_NOTIFY_UNTRACKED, NULL, wd));
  		break;
  	case GIT_DELTA_ADDED:/* case 4 (and 7 for dir) */
  	case GIT_DELTA_MODIFIED: /* case 20 (or 37 but not really) */
  		if (delta->old_file.mode == GIT_FILEMODE_COMMIT)
  			/* expected submodule (and maybe found one) */;
  		else if (delta->new_file.mode != GIT_FILEMODE_TREE)
  			*action = git_iterator_current_is_ignored(workdir) ?
  				CHECKOUT_ACTION_IF(DONT_OVERWRITE_IGNORED, CONFLICT, REMOVE_AND_UPDATE) :
  				CHECKOUT_ACTION_IF(FORCE, REMOVE_AND_UPDATE, CONFLICT);
  		break;
  	case GIT_DELTA_DELETED: /* case 11 (and 27 for dir) */
  		if (delta->old_file.mode != GIT_FILEMODE_TREE)
  			GITERR_CHECK_ERROR(
  				checkout_notify(data, GIT_CHECKOUT_NOTIFY_UNTRACKED, NULL, wd));
  		break;
  	case GIT_DELTA_TYPECHANGE: /* case 24 or 31 */
  		if (delta->old_file.mode == GIT_FILEMODE_TREE) {
  			/* For typechange from dir, remove dir and add blob, but it is
  			 * not safe to remove dir if it contains modified files.
  			 * However, safely removing child files will remove the parent
  			 * directory if is it left empty, so we can defer removing the
  			 * dir and it will succeed if no children are left.
  			 */
  			*action = CHECKOUT_ACTION_IF(SAFE, UPDATE_BLOB, NONE);
  			if (*action != CHECKOUT_ACTION__NONE)
  				*action |= CHECKOUT_ACTION__DEFER_REMOVE;
  		}
  		else if (delta->new_file.mode != GIT_FILEMODE_TREE)
  			/* For typechange to dir, dir is already created so no action */
  			*action = CHECKOUT_ACTION_IF(FORCE, REMOVE_AND_UPDATE, CONFLICT);
  		break;
  	default: /* impossible */
  		break;
  	}
  
  	return checkout_action_common(action, data, delta, wd);
  }
  
  static int checkout_action(
  	int *action,
  	checkout_data *data,
  	git_diff_delta *delta,
  	git_iterator *workdir,
  	const git_index_entry **wditem,
  	git_vector *pathspec)
  {
  	int cmp = -1, error;
  	int (*strcomp)(const char *, const char *) = data->diff->strcomp;
  	int (*pfxcomp)(const char *str, const char *pfx) = data->diff->pfxcomp;
  	int (*advance)(const git_index_entry **, git_iterator *) = NULL;
  
  	/* move workdir iterator to follow along with deltas */
  
  	while (1) {
  		const git_index_entry *wd = *wditem;
  
  		if (!wd)
  			return checkout_action_no_wd(action, data, delta);
  
  		cmp = strcomp(wd->path, delta->old_file.path);
  
  		/* 1. wd before delta ("a/a" before "a/b")
  		 * 2. wd prefixes delta & should expand ("a/" before "a/b")
  		 * 3. wd prefixes delta & cannot expand ("a/b" before "a/b/c")
  		 * 4. wd equals delta ("a/b" and "a/b")
  		 * 5. wd after delta & delta prefixes wd ("a/b/c" after "a/b/" or "a/b")
  		 * 6. wd after delta ("a/c" after "a/b")
  		 */
  
  		if (cmp < 0) {
  			cmp = pfxcomp(delta->old_file.path, wd->path);
  
  			if (cmp == 0) {
  				if (wd->mode == GIT_FILEMODE_TREE) {
  					/* case 2 - entry prefixed by workdir tree */
  					error = git_iterator_advance_into_or_over(wditem, workdir);
  					if (error < 0 && error != GIT_ITEROVER)
  						goto done;
  					continue;
  				}
  
  				/* case 3 maybe - wd contains non-dir where dir expected */
  				if (delta->old_file.path[strlen(wd->path)] == '/') {
  					error = checkout_action_with_wd_blocker(
  						action, data, delta, wd);
  					advance = git_iterator_advance;
  					goto done;
  				}
  			}
  
  			/* case 1 - handle wd item (if it matches pathspec) */
  			error = checkout_action_wd_only(data, workdir, wditem, pathspec);
  			if (error && error != GIT_ITEROVER)
  				goto done;
  			continue;
  		}
  
  		if (cmp == 0) {
  			/* case 4 */
  			error = checkout_action_with_wd(action, data, delta, workdir, wd);
  			advance = git_iterator_advance;
  			goto done;
  		}
  
  		cmp = pfxcomp(wd->path, delta->old_file.path);
  
  		if (cmp == 0) { /* case 5 */
  			if (wd->path[strlen(delta->old_file.path)] != '/')
  				return checkout_action_no_wd(action, data, delta);
  
  			if (delta->status == GIT_DELTA_TYPECHANGE) {
  				if (delta->old_file.mode == GIT_FILEMODE_TREE) {
  					error = checkout_action_with_wd(action, data, delta, workdir, wd);
  					advance = git_iterator_advance_into;
  					goto done;
  				}
  
  				if (delta->new_file.mode == GIT_FILEMODE_TREE ||
  					delta->new_file.mode == GIT_FILEMODE_COMMIT ||
  					delta->old_file.mode == GIT_FILEMODE_COMMIT)
  				{
  					error = checkout_action_with_wd(action, data, delta, workdir, wd);
  					advance = git_iterator_advance;
  					goto done;
  				}
  			}
  
  			return checkout_action_with_wd_dir(action, data, delta, workdir, wd);
  		}
  
  		/* case 6 - wd is after delta */
  		return checkout_action_no_wd(action, data, delta);
  	}
  
  done:
  	if (!error && advance != NULL &&
  		(error = advance(wditem, workdir)) < 0) {
  		*wditem = NULL;
  		if (error == GIT_ITEROVER)
  			error = 0;
  	}
  
  	return error;
  }
  
  static int checkout_remaining_wd_items(
  	checkout_data *data,
  	git_iterator *workdir,
  	const git_index_entry *wd,
  	git_vector *spec)
  {
  	int error = 0;
  
  	while (wd && !error)
  		error = checkout_action_wd_only(data, workdir, &wd, spec);
  
  	if (error == GIT_ITEROVER)
  		error = 0;
  
  	return error;
  }
  
  GIT_INLINE(int) checkout_idxentry_cmp(
  	const git_index_entry *a,
  	const git_index_entry *b)
  {
  	if (!a && !b)
  		return 0;
  	else if (!a && b)
  		return -1;
  	else if(a && !b)
  		return 1;
  	else
  		return strcmp(a->path, b->path);
  }
  
  static int checkout_conflictdata_cmp(const void *a, const void *b)
  {
  	const checkout_conflictdata *ca = a;
  	const checkout_conflictdata *cb = b;
  	int diff;
  
  	if ((diff = checkout_idxentry_cmp(ca->ancestor, cb->ancestor)) == 0 &&
  		(diff = checkout_idxentry_cmp(ca->ours, cb->theirs)) == 0)
  		diff = checkout_idxentry_cmp(ca->theirs, cb->theirs);
  
  	return diff;
  }
  
  int checkout_conflictdata_empty(
  	const git_vector *conflicts, size_t idx, void *payload)
  {
  	checkout_conflictdata *conflict;
  
  	GIT_UNUSED(payload);
  
  	if ((conflict = git_vector_get(conflicts, idx)) == NULL)
  		return -1;
  
  	if (conflict->ancestor || conflict->ours || conflict->theirs)
  		return 0;
  
  	git__free(conflict);
  	return 1;
  }
  
  GIT_INLINE(bool) conflict_pathspec_match(
  	checkout_data *data,
  	git_iterator *workdir,
  	git_vector *pathspec,
  	const git_index_entry *ancestor,
  	const git_index_entry *ours,
  	const git_index_entry *theirs)
  {
  	/* if the pathspec matches ours *or* theirs, proceed */
  	if (ours && git_pathspec__match(pathspec, ours->path,
  		(data->strategy & GIT_CHECKOUT_DISABLE_PATHSPEC_MATCH) != 0,
  		git_iterator_ignore_case(workdir), NULL, NULL))
  		return true;
  
  	if (theirs && git_pathspec__match(pathspec, theirs->path,
  		(data->strategy & GIT_CHECKOUT_DISABLE_PATHSPEC_MATCH) != 0,
  		git_iterator_ignore_case(workdir), NULL, NULL))
  		return true;
  
  	if (ancestor && git_pathspec__match(pathspec, ancestor->path,
  		(data->strategy & GIT_CHECKOUT_DISABLE_PATHSPEC_MATCH) != 0,
  		git_iterator_ignore_case(workdir), NULL, NULL))
  		return true;
  
  	return false;
  }
  
  GIT_INLINE(int) checkout_conflict_detect_submodule(checkout_conflictdata *conflict)
  {
  	conflict->submodule = ((conflict->ancestor && S_ISGITLINK(conflict->ancestor->mode)) ||
  		(conflict->ours && S_ISGITLINK(conflict->ours->mode)) ||
  		(conflict->theirs && S_ISGITLINK(conflict->theirs->mode)));
  	return 0;
  }
  
  GIT_INLINE(int) checkout_conflict_detect_binary(git_repository *repo, checkout_conflictdata *conflict)
  {
  	git_blob *ancestor_blob = NULL, *our_blob = NULL, *their_blob = NULL;
  	int error = 0;
  
  	if (conflict->submodule)
  		return 0;
  
  	if (conflict->ancestor) {
  		if ((error = git_blob_lookup(&ancestor_blob, repo, &conflict->ancestor->id)) < 0)
  			goto done;
  
  		conflict->binary = git_blob_is_binary(ancestor_blob);
  	}
  
  	if (!conflict->binary && conflict->ours) {
  		if ((error = git_blob_lookup(&our_blob, repo, &conflict->ours->id)) < 0)
  			goto done;
  
  		conflict->binary = git_blob_is_binary(our_blob);
  	}
  
  	if (!conflict->binary && conflict->theirs) {
  		if ((error = git_blob_lookup(&their_blob, repo, &conflict->theirs->id)) < 0)
  			goto done;
  
  		conflict->binary = git_blob_is_binary(their_blob);
  	}
  
  done:
  	git_blob_free(ancestor_blob);
  	git_blob_free(our_blob);
  	git_blob_free(their_blob);
  
  	return error;
  }
  
  static int checkout_conflict_append_update(
  	const git_index_entry *ancestor,
  	const git_index_entry *ours,
  	const git_index_entry *theirs,
  	void *payload)
  {
  	checkout_data *data = payload;
  	checkout_conflictdata *conflict;
  	int error;
  
  	conflict = git__calloc(1, sizeof(checkout_conflictdata));
  	GITERR_CHECK_ALLOC(conflict);
  
  	conflict->ancestor = ancestor;
  	conflict->ours = ours;
  	conflict->theirs = theirs;
  
  	if ((error = checkout_conflict_detect_submodule(conflict)) < 0 ||
  		(error = checkout_conflict_detect_binary(data->repo, conflict)) < 0)
  	{
  		git__free(conflict);
  		return error;
  	}
  
  	if (git_vector_insert(&data->update_conflicts, conflict))
  		return -1;
  
  	return 0;
  }
  
  static int checkout_conflicts_foreach(
  	checkout_data *data,
  	git_index *index,
  	git_iterator *workdir,
  	git_vector *pathspec,
  	int (*cb)(const git_index_entry *, const git_index_entry *, const git_index_entry *, void *),
  	void *payload)
  {
  	git_index_conflict_iterator *iterator = NULL;
  	const git_index_entry *ancestor, *ours, *theirs;
  	int error = 0;
  
  	if ((error = git_index_conflict_iterator_new(&iterator, index)) < 0)
  		goto done;
  
  	/* Collect the conflicts */
  	while ((error = git_index_conflict_next(&ancestor, &ours, &theirs, iterator)) == 0) {
  		if (!conflict_pathspec_match(data, workdir, pathspec, ancestor, ours, theirs))
  			continue;
  
  		if ((error = cb(ancestor, ours, theirs, payload)) < 0)
  			goto done;
  	}
  
  	if (error == GIT_ITEROVER)
  		error = 0;
  
  done:
  	git_index_conflict_iterator_free(iterator);
  
  	return error;
  }
  
  static int checkout_conflicts_load(checkout_data *data, git_iterator *workdir, git_vector *pathspec)
  {
  	git_index *index;
  
  	/* Only write conficts from sources that have them: indexes. */
  	if ((index = git_iterator_get_index(data->target)) == NULL)
  		return 0;
  
  	data->update_conflicts._cmp = checkout_conflictdata_cmp;
  
  	if (checkout_conflicts_foreach(data, index, workdir, pathspec, checkout_conflict_append_update, data) < 0)
  		return -1;
  
  	/* Collect the REUC and NAME entries */
  	data->update_reuc = &index->reuc;
  	data->update_names = &index->names;
  
  	return 0;
  }
  
  GIT_INLINE(int) checkout_conflicts_cmp_entry(
  	const char *path,
  	const git_index_entry *entry)
  {
  	return strcmp((const char *)path, entry->path);
  }
  
  static int checkout_conflicts_cmp_ancestor(const void *p, const void *c)
  {
  	const char *path = p;
  	const checkout_conflictdata *conflict = c;
  
  	if (!conflict->ancestor)
  		return 1;
  
  	return checkout_conflicts_cmp_entry(path, conflict->ancestor);
  }
  
  static checkout_conflictdata *checkout_conflicts_search_ancestor(
  	checkout_data *data,
  	const char *path)
  {
  	size_t pos;
  
  	if (git_vector_bsearch2(&pos, &data->update_conflicts, checkout_conflicts_cmp_ancestor, path) < 0)
  		return NULL;
  
  	return git_vector_get(&data->update_conflicts, pos);
  }
  
  static checkout_conflictdata *checkout_conflicts_search_branch(
  	checkout_data *data,
  	const char *path)
  {
  	checkout_conflictdata *conflict;
  	size_t i;
  
  	git_vector_foreach(&data->update_conflicts, i, conflict) {
  		int cmp = -1;
  
  		if (conflict->ancestor)
  			break;
  
  		if (conflict->ours)
  			cmp = checkout_conflicts_cmp_entry(path, conflict->ours);
  		else if (conflict->theirs)
  			cmp = checkout_conflicts_cmp_entry(path, conflict->theirs);
  
  		if (cmp == 0)
  			return conflict;
  	}
  
  	return NULL;
  }
  
  static int checkout_conflicts_load_byname_entry(
  	checkout_conflictdata **ancestor_out,
  	checkout_conflictdata **ours_out,
  	checkout_conflictdata **theirs_out,
  	checkout_data *data,
  	const git_index_name_entry *name_entry)
  {
  	checkout_conflictdata *ancestor, *ours = NULL, *theirs = NULL;
  	int error = 0;
  
  	*ancestor_out = NULL;
  	*ours_out = NULL;
  	*theirs_out = NULL;
  
  	if (!name_entry->ancestor) {
  		giterr_set(GITERR_INDEX, "A NAME entry exists without an ancestor");
  		error = -1;
  		goto done;
  	}
  
  	if (!name_entry->ours && !name_entry->theirs) {
  		giterr_set(GITERR_INDEX, "A NAME entry exists without an ours or theirs");
  		error = -1;
  		goto done;
  	}
  
  	if ((ancestor = checkout_conflicts_search_ancestor(data,
  		name_entry->ancestor)) == NULL) {
  		giterr_set(GITERR_INDEX,
  			"A NAME entry referenced ancestor entry '%s' which does not exist in the main index",
  			name_entry->ancestor);
  		error = -1;
  		goto done;
  	}
  
  	if (name_entry->ours) {
  		if (strcmp(name_entry->ancestor, name_entry->ours) == 0)
  			ours = ancestor;
  		else if ((ours = checkout_conflicts_search_branch(data, name_entry->ours)) == NULL ||
  			ours->ours == NULL) {
  			giterr_set(GITERR_INDEX,
  				"A NAME entry referenced our entry '%s' which does not exist in the main index",
  				name_entry->ours);
  			error = -1;
  			goto done;
  		}
  	}
  
  	if (name_entry->theirs) {
  		if (strcmp(name_entry->ancestor, name_entry->theirs) == 0)
  			theirs = ancestor;
  		else if (name_entry->ours && strcmp(name_entry->ours, name_entry->theirs) == 0)
  			theirs = ours;
  		else if ((theirs = checkout_conflicts_search_branch(data, name_entry->theirs)) == NULL ||
  			theirs->theirs == NULL) {
  			giterr_set(GITERR_INDEX,
  				"A NAME entry referenced their entry '%s' which does not exist in the main index",
  				name_entry->theirs);
  			error = -1;
  			goto done;
  		}
  	}
  
  	*ancestor_out = ancestor;
  	*ours_out = ours;
  	*theirs_out = theirs;
  
  done:
  	return error;
  }
  
  static int checkout_conflicts_coalesce_renames(
  	checkout_data *data)
  {
  	git_index *index;
  	const git_index_name_entry *name_entry;
  	checkout_conflictdata *ancestor_conflict, *our_conflict, *their_conflict;
  	size_t i, names;
  	int error = 0;
  
  	if ((index = git_iterator_get_index(data->target)) == NULL)
  		return 0;
  
  	/* Juggle entries based on renames */
  	names = git_index_name_entrycount(index);
  
  	for (i = 0; i < names; i++) {
  		name_entry = git_index_name_get_byindex(index, i);
  
  		if ((error = checkout_conflicts_load_byname_entry(
  			&ancestor_conflict, &our_conflict, &their_conflict,
  			data, name_entry)) < 0)
  			goto done;
  
  		if (our_conflict && our_conflict != ancestor_conflict) {
  			ancestor_conflict->ours = our_conflict->ours;
  			our_conflict->ours = NULL;
  
  			if (our_conflict->theirs)
  				our_conflict->name_collision = 1;
  
  			if (our_conflict->name_collision)
  				ancestor_conflict->name_collision = 1;
  		}
  
  		if (their_conflict && their_conflict != ancestor_conflict) {
  			ancestor_conflict->theirs = their_conflict->theirs;
  			their_conflict->theirs = NULL;
  
  			if (their_conflict->ours)
  				their_conflict->name_collision = 1;
  
  			if (their_conflict->name_collision)
  				ancestor_conflict->name_collision = 1;
  		}
  
  		if (our_conflict && our_conflict != ancestor_conflict &&
  			their_conflict && their_conflict != ancestor_conflict)
  			ancestor_conflict->one_to_two = 1;
  	}
  
  	git_vector_remove_matching(
  		&data->update_conflicts, checkout_conflictdata_empty, NULL);
  
  done:
  	return error;
  }
  
  static int checkout_conflicts_mark_directoryfile(
  	checkout_data *data)
  {
  	git_index *index;
  	checkout_conflictdata *conflict;
  	const git_index_entry *entry;
  	size_t i, j, len;
  	const char *path;
  	int prefixed, error = 0;
  
  	if ((index = git_iterator_get_index(data->target)) == NULL)
  		return 0;
  
  	len = git_index_entrycount(index);
  
  	/* Find d/f conflicts */
  	git_vector_foreach(&data->update_conflicts, i, conflict) {
  		if ((conflict->ours && conflict->theirs) ||
  			(!conflict->ours && !conflict->theirs))
  			continue;
  
  		path = conflict->ours ?
  			conflict->ours->path : conflict->theirs->path;
  
  		if ((error = git_index_find(&j, index, path)) < 0) {
  			if (error == GIT_ENOTFOUND)
  				giterr_set(GITERR_INDEX,
  					"Index inconsistency, could not find entry for expected conflict '%s'", path);
  
  			goto done;
  		}
  
  		for (; j < len; j++) {
  			if ((entry = git_index_get_byindex(index, j)) == NULL) {
  				giterr_set(GITERR_INDEX,
  					"Index inconsistency, truncated index while loading expected conflict '%s'", path);
  				error = -1;
  				goto done;
  			}
  
  			prefixed = git_path_equal_or_prefixed(path, entry->path);
  
  			if (prefixed == GIT_PATH_EQUAL)
  				continue;
  
  			if (prefixed == GIT_PATH_PREFIX)
  				conflict->directoryfile = 1;
  
  			break;
  		}
  	}
  
  done:
  	return error;
  }
  
  static int checkout_get_update_conflicts(
  	checkout_data *data,
  	git_iterator *workdir,
  	git_vector *pathspec)
  {
  	int error = 0;
  
  	if (data->strategy & GIT_CHECKOUT_SKIP_UNMERGED)
  		return 0;
  
  	if ((error = checkout_conflicts_load(data, workdir, pathspec)) < 0 ||
  		(error = checkout_conflicts_coalesce_renames(data)) < 0 ||
  		(error = checkout_conflicts_mark_directoryfile(data)) < 0)
  		goto done;
  
  done:
  	return error;
  }
  
  static int checkout_conflict_append_remove(
  	const git_index_entry *ancestor,
  	const git_index_entry *ours,
  	const git_index_entry *theirs,
  	void *payload)
  {
  	checkout_data *data = payload;
  	const char *name;
  
  	if (ancestor)
  		name = git__strdup(ancestor->path);
  	else if (ours)
  		name = git__strdup(ours->path);
  	else if (theirs)
  		name = git__strdup(theirs->path);
  
  	GITERR_CHECK_ALLOC(name);
  
  	return git_vector_insert(&data->remove_conflicts, (char *)name);
  }
  
  static int checkout_get_remove_conflicts(
  	checkout_data *data,
  	git_iterator *workdir,
  	git_vector *pathspec)
  {
  	if ((data->strategy & GIT_CHECKOUT_DONT_UPDATE_INDEX) != 0)
  		return 0;
  
  	return checkout_conflicts_foreach(data, data->index, workdir, pathspec, checkout_conflict_append_remove, data);
  }
  
  static int checkout_get_actions(
  	uint32_t **actions_ptr,
  	size_t **counts_ptr,
  	checkout_data *data,
  	git_iterator *workdir)
  {
  	int error = 0, act;
  	const git_index_entry *wditem;
  	git_vector pathspec = GIT_VECTOR_INIT, *deltas;
  	git_pool pathpool = GIT_POOL_INIT_STRINGPOOL;
  	git_diff_delta *delta;
  	size_t i, *counts = NULL;
  	uint32_t *actions = NULL;
  
  	if (data->opts.paths.count > 0 &&
  		git_pathspec__vinit(&pathspec, &data->opts.paths, &pathpool) < 0)
  		return -1;
  
  	if ((error = git_iterator_current(&wditem, workdir)) < 0 &&
  		error != GIT_ITEROVER)
  		goto fail;
  
  	deltas = &data->diff->deltas;
  
  	*counts_ptr = counts = git__calloc(CHECKOUT_ACTION__MAX+1, sizeof(size_t));
  	*actions_ptr = actions = git__calloc(
  		deltas->length ? deltas->length : 1, sizeof(uint32_t));
  	if (!counts || !actions) {
  		error = -1;
  		goto fail;
  	}
  
  	git_vector_foreach(deltas, i, delta) {
  		error = checkout_action(&act, data, delta, workdir, &wditem, &pathspec);
  		if (error != 0)
  			goto fail;
  
  		actions[i] = act;
  
  		if (act & CHECKOUT_ACTION__REMOVE)
  			counts[CHECKOUT_ACTION__REMOVE]++;
  		if (act & CHECKOUT_ACTION__UPDATE_BLOB)
  			counts[CHECKOUT_ACTION__UPDATE_BLOB]++;
  		if (act & CHECKOUT_ACTION__UPDATE_SUBMODULE)
  			counts[CHECKOUT_ACTION__UPDATE_SUBMODULE]++;
  		if (act & CHECKOUT_ACTION__CONFLICT)
  			counts[CHECKOUT_ACTION__CONFLICT]++;
  	}
  
  	error = checkout_remaining_wd_items(data, workdir, wditem, &pathspec);
  	if (error)
  		goto fail;
  
  	counts[CHECKOUT_ACTION__REMOVE] += data->removes.length;
  
  	if (counts[CHECKOUT_ACTION__CONFLICT] > 0 &&
  		(data->strategy & GIT_CHECKOUT_ALLOW_CONFLICTS) == 0)
  	{
  		giterr_set(GITERR_CHECKOUT, "%d %s checkout",
  			(int)counts[CHECKOUT_ACTION__CONFLICT],
  			counts[CHECKOUT_ACTION__CONFLICT] == 1 ?
  			"conflict prevents" : "conflicts prevent");
  		error = GIT_EMERGECONFLICT;
  		goto fail;
  	}
  
  
  	if ((error = checkout_get_remove_conflicts(data, workdir, &pathspec)) < 0 ||
  		(error = checkout_get_update_conflicts(data, workdir, &pathspec)) < 0)
  		goto fail;
  
  	counts[CHECKOUT_ACTION__REMOVE_CONFLICT] = git_vector_length(&data->remove_conflicts);
  	counts[CHECKOUT_ACTION__UPDATE_CONFLICT] = git_vector_length(&data->update_conflicts);
  
  	git_pathspec__vfree(&pathspec);
  	git_pool_clear(&pathpool);
  
  	return 0;
  
  fail:
  	*counts_ptr = NULL;
  	git__free(counts);
  	*actions_ptr = NULL;
  	git__free(actions);
  
  	git_pathspec__vfree(&pathspec);
  	git_pool_clear(&pathpool);
  
  	return error;
  }
  
  static int buffer_to_file(
  	struct stat *st,
  	git_buf *buf,
  	const char *path,
  	mode_t dir_mode,
  	int file_open_flags,
  	mode_t file_mode)
  {
  	int error;
  
  	if ((error = git_futils_mkpath2file(path, dir_mode)) < 0)
  		return error;
  
  	if ((error = git_futils_writebuffer(
  			buf, path, file_open_flags, file_mode)) < 0)
  		return error;
  
  	if (st != NULL && (error = p_stat(path, st)) < 0)
  		giterr_set(GITERR_OS, "Error statting '%s'", path);
  
  	else if (GIT_PERMS_IS_EXEC(file_mode) &&
  			(error = p_chmod(path, file_mode)) < 0)
  		giterr_set(GITERR_OS, "Failed to set permissions on '%s'", path);
  
  	return error;
  }
  
  static int blob_content_to_file(
  	struct stat *st,
  	git_blob *blob,
  	const char *path,
  	const char * hint_path,
  	mode_t entry_filemode,
  	git_checkout_options *opts)
  {
  	int error = 0;
  	mode_t file_mode = opts->file_mode ? opts->file_mode : entry_filemode;
  	git_buf out = GIT_BUF_INIT;
  	git_filter_list *fl = NULL;
  
  	if (hint_path == NULL)
  		hint_path = path;
  
  	if (!opts->disable_filters)
  		error = git_filter_list_load(
  			&fl, git_blob_owner(blob), blob, hint_path,
  			GIT_FILTER_TO_WORKTREE, GIT_FILTER_OPT_DEFAULT);
  
  	if (!error)
  		error = git_filter_list_apply_to_blob(&out, fl, blob);
  
  	git_filter_list_free(fl);
  
  	if (!error) {
  		error = buffer_to_file(
  			st, &out, path, opts->dir_mode, opts->file_open_flags, file_mode);
  
  		st->st_mode = entry_filemode;
  
  		git_buf_free(&out);
  	}
  
  	return error;
  }
  
  static int blob_content_to_link(
  	struct stat *st,
  	git_blob *blob,
  	const char *path,
  	mode_t dir_mode,
  	int can_symlink)
  {
  	git_buf linktarget = GIT_BUF_INIT;
  	int error;
  
  	if ((error = git_futils_mkpath2file(path, dir_mode)) < 0)
  		return error;
  
  	if ((error = git_blob__getbuf(&linktarget, blob)) < 0)
  		return error;
  
  	if (can_symlink) {
  		if ((error = p_symlink(git_buf_cstr(&linktarget), path)) < 0)
  			giterr_set(GITERR_OS, "Could not create symlink %s\n", path);
  	} else {
  		error = git_futils_fake_symlink(git_buf_cstr(&linktarget), path);
  	}
  
  	if (!error) {
  		if ((error = p_lstat(path, st)) < 0)
  			giterr_set(GITERR_CHECKOUT, "Could not stat symlink %s", path);
  
  		st->st_mode = GIT_FILEMODE_LINK;
  	}
  
  	git_buf_free(&linktarget);
  
  	return error;
  }
  
  static int checkout_update_index(
  	checkout_data *data,
  	const git_diff_file *file,
  	struct stat *st)
  {
  	git_index_entry entry;
  
  	if (!data->index)
  		return 0;
  
  	memset(&entry, 0, sizeof(entry));
  	entry.path = (char *)file->path; /* cast to prevent warning */
  	git_index_entry__init_from_stat(&entry, st, true);
  	git_oid_cpy(&entry.id, &file->id);
  
  	return git_index_add(data->index, &entry);
  }
  
  static int checkout_submodule_update_index(
  	checkout_data *data,
  	const git_diff_file *file)
  {
  	struct stat st;
  
  	/* update the index unless prevented */
  	if ((data->strategy & GIT_CHECKOUT_DONT_UPDATE_INDEX) != 0)
  		return 0;
  
  	git_buf_truncate(&data->path, data->workdir_len);
  	if (git_buf_puts(&data->path, file->path) < 0)
  		return -1;
  
  	if (p_stat(git_buf_cstr(&data->path), &st) < 0) {
  		giterr_set(
  			GITERR_CHECKOUT, "Could not stat submodule %s\n", file->path);
  		return GIT_ENOTFOUND;
  	}
  
  	st.st_mode = GIT_FILEMODE_COMMIT;
  
  	return checkout_update_index(data, file, &st);
  }
  
  static int checkout_submodule(
  	checkout_data *data,
  	const git_diff_file *file)
  {
  	int error = 0;
  
  	/* Until submodules are supported, UPDATE_ONLY means do nothing here */
  	if ((data->strategy & GIT_CHECKOUT_UPDATE_ONLY) != 0)
  		return 0;
  
  	if ((error = git_futils_mkdir(
  			file->path, data->opts.target_directory,
  			data->opts.dir_mode, GIT_MKDIR_PATH)) < 0)
  		return error;
  
  	if ((error = git_submodule_lookup(NULL, data->repo, file->path)) < 0) {
  		/* I've observed repos with submodules in the tree that do not
  		 * have a .gitmodules - core Git just makes an empty directory
  		 */
  		if (error == GIT_ENOTFOUND) {
  			giterr_clear();
  			return checkout_submodule_update_index(data, file);
  		}
  
  		return error;
  	}
  
  	/* TODO: Support checkout_strategy options.  Two circumstances:
  	 * 1 - submodule already checked out, but we need to move the HEAD
  	 *     to the new OID, or
  	 * 2 - submodule not checked out and we should recursively check it out
  	 *
  	 * Checkout will not execute a pull on the submodule, but a clone
  	 * command should probably be able to.  Do we need a submodule callback?
  	 */
  
  	return checkout_submodule_update_index(data, file);
  }
  
  static void report_progress(
  	checkout_data *data,
  	const char *path)
  {
  	if (data->opts.progress_cb)
  		data->opts.progress_cb(
  			path, data->completed_steps, data->total_steps,
  			data->opts.progress_payload);
  }
  
  static int checkout_safe_for_update_only(const char *path, mode_t expected_mode)
  {
  	struct stat st;
  
  	if (p_lstat(path, &st) < 0) {
  		/* if doesn't exist, then no error and no update */
  		if (errno == ENOENT || errno == ENOTDIR)
  			return 0;
  
  		/* otherwise, stat error and no update */
  		giterr_set(GITERR_OS, "Failed to stat file '%s'", path);
  		return -1;
  	}
  
  	/* only safe for update if this is the same type of file */
  	if ((st.st_mode & ~0777) == (expected_mode & ~0777))
  		return 1;
  
  	return 0;
  }
  
  static int checkout_write_content(
  	checkout_data *data,
  	const git_oid *oid,
  	const char *full_path,
  	const char *hint_path,
  	unsigned int mode,
  	struct stat *st)
  {
  	int error = 0;
  	git_blob *blob;
  
  	if ((error = git_blob_lookup(&blob, data->repo, oid)) < 0)
  		return error;
  
  	if (S_ISLNK(mode))
  		error = blob_content_to_link(
  			st, blob, full_path, data->opts.dir_mode, data->can_symlink);
  	else
  		error = blob_content_to_file(
  			st, blob, full_path, hint_path, mode, &data->opts);
  
  	git_blob_free(blob);
  
  	/* if we try to create the blob and an existing directory blocks it from
  	 * being written, then there must have been a typechange conflict in a
  	 * parent directory - suppress the error and try to continue.
  	 */
  	if ((data->strategy & GIT_CHECKOUT_ALLOW_CONFLICTS) != 0 &&
  		(error == GIT_ENOTFOUND || error == GIT_EEXISTS))
  	{
  		giterr_clear();
  		error = 0;
  	}
  
  	return error;
  }
  
  static int checkout_blob(
  	checkout_data *data,
  	const git_diff_file *file)
  {
  	int error = 0;
  	struct stat st;
  
  	git_buf_truncate(&data->path, data->workdir_len);
  	if (git_buf_puts(&data->path, file->path) < 0)
  		return -1;
  
  	if ((data->strategy & GIT_CHECKOUT_UPDATE_ONLY) != 0) {
  		int rval = checkout_safe_for_update_only(
  			git_buf_cstr(&data->path), file->mode);
  		if (rval <= 0)
  			return rval;
  	}
  
  	error = checkout_write_content(
  		data, &file->id, git_buf_cstr(&data->path), NULL, file->mode, &st);
  
  	/* update the index unless prevented */
  	if (!error && (data->strategy & GIT_CHECKOUT_DONT_UPDATE_INDEX) == 0)
  		error = checkout_update_index(data, file, &st);
  
  	/* update the submodule data if this was a new .gitmodules file */
  	if (!error && strcmp(file->path, ".gitmodules") == 0)
  		data->reload_submodules = true;
  
  	return error;
  }
  
  static int checkout_remove_the_old(
  	unsigned int *actions,
  	checkout_data *data)
  {
  	int error = 0;
  	git_diff_delta *delta;
  	const char *str;
  	size_t i;
  	const char *workdir = git_buf_cstr(&data->path);
  	uint32_t flg = GIT_RMDIR_EMPTY_PARENTS |
  		GIT_RMDIR_REMOVE_FILES | GIT_RMDIR_REMOVE_BLOCKERS;
  
  	if (data->opts.checkout_strategy & GIT_CHECKOUT_SKIP_LOCKED_DIRECTORIES)
  		flg |= GIT_RMDIR_SKIP_NONEMPTY;
  
  	git_buf_truncate(&data->path, data->workdir_len);
  
  	git_vector_foreach(&data->diff->deltas, i, delta) {
  		if (actions[i] & CHECKOUT_ACTION__REMOVE) {
  			error = git_futils_rmdir_r(delta->old_file.path, workdir, flg);
  			if (error < 0)
  				return error;
  
  			data->completed_steps++;
  			report_progress(data, delta->old_file.path);
  
  			if ((actions[i] & CHECKOUT_ACTION__UPDATE_BLOB) == 0 &&
  				(data->strategy & GIT_CHECKOUT_DONT_UPDATE_INDEX) == 0 &&
  				data->index != NULL)
  			{
  				(void)git_index_remove(data->index, delta->old_file.path, 0);
  			}
  		}
  	}
  
  	git_vector_foreach(&data->removes, i, str) {
  		error = git_futils_rmdir_r(str, workdir, flg);
  		if (error < 0)
  			return error;
  
  		data->completed_steps++;
  		report_progress(data, str);
  
  		if ((data->strategy & GIT_CHECKOUT_DONT_UPDATE_INDEX) == 0 &&
  			data->index != NULL)
  		{
  			if (str[strlen(str) - 1] == '/')
  				(void)git_index_remove_directory(data->index, str, 0);
  			else
  				(void)git_index_remove(data->index, str, 0);
  		}
  	}
  
  	return 0;
  }
  
  static int checkout_deferred_remove(git_repository *repo, const char *path)
  {
  #if 0
  	int error = git_futils_rmdir_r(
  		path, data->opts.target_directory, GIT_RMDIR_EMPTY_PARENTS);
  
  	if (error == GIT_ENOTFOUND) {
  		error = 0;
  		giterr_clear();
  	}
  
  	return error;
  #else
  	GIT_UNUSED(repo);
  	GIT_UNUSED(path);
  	assert(false);
  	return 0;
  #endif
  }
  
  static int checkout_create_the_new(
  	unsigned int *actions,
  	checkout_data *data)
  {
  	int error = 0;
  	git_diff_delta *delta;
  	size_t i;
  
  	git_vector_foreach(&data->diff->deltas, i, delta) {
  		if (actions[i] & CHECKOUT_ACTION__DEFER_REMOVE) {
  			/* this had a blocker directory that should only be removed iff
  			 * all of the contents of the directory were safely removed
  			 */
  			if ((error = checkout_deferred_remove(
  					data->repo, delta->old_file.path)) < 0)
  				return error;
  		}
  
  		if (actions[i] & CHECKOUT_ACTION__UPDATE_BLOB) {
  			error = checkout_blob(data, &delta->new_file);
  			if (error < 0)
  				return error;
  
  			data->completed_steps++;
  			report_progress(data, delta->new_file.path);
  		}
  	}
  
  	return 0;
  }
  
  static int checkout_create_submodules(
  	unsigned int *actions,
  	checkout_data *data)
  {
  	int error = 0;
  	git_diff_delta *delta;
  	size_t i;
  
  	/* initial reload of submodules if .gitmodules was changed */
  	if (data->reload_submodules &&
  		(error = git_submodule_reload_all(data->repo, 1)) < 0)
  		return error;
  
  	git_vector_foreach(&data->diff->deltas, i, delta) {
  		if (actions[i] & CHECKOUT_ACTION__DEFER_REMOVE) {
  			/* this has a blocker directory that should only be removed iff
  			 * all of the contents of the directory were safely removed
  			 */
  			if ((error = checkout_deferred_remove(
  					data->repo, delta->old_file.path)) < 0)
  				return error;
  		}
  
  		if (actions[i] & CHECKOUT_ACTION__UPDATE_SUBMODULE) {
  			int error = checkout_submodule(data, &delta->new_file);
  			if (error < 0)
  				return error;
  
  			data->completed_steps++;
  			report_progress(data, delta->new_file.path);
  		}
  	}
  
  	/* final reload once submodules have been updated */
  	return git_submodule_reload_all(data->repo, 1);
  }
  
  static int checkout_lookup_head_tree(git_tree **out, git_repository *repo)
  {
  	int error = 0;
  	git_reference *ref = NULL;
  	git_object *head;
  
  	if (!(error = git_repository_head(&ref, repo)) &&
  		!(error = git_reference_peel(&head, ref, GIT_OBJ_TREE)))
  		*out = (git_tree *)head;
  
  	git_reference_free(ref);
  
  	return error;
  }
  
  
  static int conflict_entry_name(
  	git_buf *out,
  	const char *side_name,
  	const char *filename)
  {
  	if (git_buf_puts(out, side_name) < 0 ||
  		git_buf_putc(out, ':') < 0 ||
  		git_buf_puts(out, filename) < 0)
  		return -1;
  
  	return 0;
  }
  
  static int checkout_path_suffixed(git_buf *path, const char *suffix)
  {
  	size_t path_len;
  	int i = 0, error = 0;
  
  	if ((error = git_buf_putc(path, '~')) < 0 || (error = git_buf_puts(path, suffix)) < 0)
  		return -1;
  
  	path_len = git_buf_len(path);
  
  	while (git_path_exists(git_buf_cstr(path)) && i < INT_MAX) {
  		git_buf_truncate(path, path_len);
  
  		if ((error = git_buf_putc(path, '_')) < 0 ||
  			(error = git_buf_printf(path, "%d", i)) < 0)
  			return error;
  
  		i++;
  	}
  
  	if (i == INT_MAX) {
  		git_buf_truncate(path, path_len);
  
  		giterr_set(GITERR_CHECKOUT, "Could not write '%s': working directory file exists", path);
  		return GIT_EEXISTS;
  	}
  
  	return 0;
  }
  
  static int checkout_write_entry(
  	checkout_data *data,
  	checkout_conflictdata *conflict,
  	const git_index_entry *side)
  {
  	const char *hint_path = NULL, *suffix;
  	struct stat st;
  	int error;
  
  	assert (side == conflict->ours || side == conflict->theirs);
  
  	git_buf_truncate(&data->path, data->workdir_len);
  	if (git_buf_puts(&data->path, side->path) < 0)
  		return -1;
  
  	if ((conflict->name_collision || conflict->directoryfile) &&
  		(data->strategy & GIT_CHECKOUT_USE_OURS) == 0 &&
  		(data->strategy & GIT_CHECKOUT_USE_THEIRS) == 0) {
  
  		if (side == conflict->ours)
  			suffix = data->opts.our_label ? data->opts.our_label :
  				"ours";
  		else
  			suffix = data->opts.their_label ? data->opts.their_label :
  				"theirs";
  
  		if (checkout_path_suffixed(&data->path, suffix) < 0)
  			return -1;
  
  		hint_path = side->path;
  	}
  
  	if ((data->strategy & GIT_CHECKOUT_UPDATE_ONLY) != 0 &&
  		(error = checkout_safe_for_update_only(git_buf_cstr(&data->path), side->mode)) <= 0)
  		return error;
  
  	return checkout_write_content(data,
  		&side->id, git_buf_cstr(&data->path), hint_path, side->mode, &st);
  }
  
  static int checkout_write_entries(
  	checkout_data *data,
  	checkout_conflictdata *conflict)
  {
  	int error = 0;
  
  	if ((error = checkout_write_entry(data, conflict, conflict->ours)) >= 0)
  		error = checkout_write_entry(data, conflict, conflict->theirs);
  
  	return error;
  }
  
  static int checkout_merge_path(
  	git_buf *out,
  	checkout_data *data,
  	checkout_conflictdata *conflict,
  	git_merge_file_result *result)
  {
  	const char *our_label_raw, *their_label_raw, *suffix;
  	int error = 0;
  
  	if ((error = git_buf_joinpath(out, git_repository_workdir(data->repo), result->path)) < 0)
  		return error;
  
  	/* Most conflicts simply use the filename in the index */
  	if (!conflict->name_collision)
  		return 0;
  
  	/* Rename 2->1 conflicts need the branch name appended */
  	our_label_raw = data->opts.our_label ? data->opts.our_label : "ours";
  	their_label_raw = data->opts.their_label ? data->opts.their_label : "theirs";
  	suffix = strcmp(result->path, conflict->ours->path) == 0 ? our_label_raw : their_label_raw;
  
  	if ((error = checkout_path_suffixed(out, suffix)) < 0)
  		return error;
  
  	return 0;
  }
  
  static int checkout_write_merge(
  	checkout_data *data,
  	checkout_conflictdata *conflict)
  {
  	git_buf our_label = GIT_BUF_INIT, their_label = GIT_BUF_INIT,
  		path_suffixed = GIT_BUF_INIT, path_workdir = GIT_BUF_INIT,
  		in_data = GIT_BUF_INIT, out_data = GIT_BUF_INIT;
  	git_merge_file_options opts = GIT_MERGE_FILE_OPTIONS_INIT;
  	git_merge_file_result result = {0};
  	git_filebuf output = GIT_FILEBUF_INIT;
  	git_filter_list *fl = NULL;
  	int error = 0;
  
  	if (data->opts.checkout_strategy & GIT_CHECKOUT_CONFLICT_STYLE_DIFF3)
  		opts.flags |= GIT_MERGE_FILE_STYLE_DIFF3;
  
  	opts.ancestor_label = data->opts.ancestor_label ?
  		data->opts.ancestor_label : "ancestor";
  	opts.our_label = data->opts.our_label ?
  		data->opts.our_label : "ours";
  	opts.their_label = data->opts.their_label ?
  		data->opts.their_label : "theirs";
  
  	/* If all the paths are identical, decorate the diff3 file with the branch
  	 * names.  Otherwise, append branch_name:path.
  	 */
  	if (conflict->ours && conflict->theirs &&
  		strcmp(conflict->ours->path, conflict->theirs->path) != 0) {
  
  		if ((error = conflict_entry_name(
  			&our_label, opts.our_label, conflict->ours->path)) < 0 ||
  			(error = conflict_entry_name(
  			&their_label, opts.their_label, conflict->theirs->path)) < 0)
  			goto done;
  
  		opts.our_label = git_buf_cstr(&our_label);
  		opts.their_label = git_buf_cstr(&their_label);
  	}
  
  	if ((error = git_merge_file_from_index(&result, data->repo,
  		conflict->ancestor, conflict->ours, conflict->theirs, &opts)) < 0)
  		goto done;
  
  	if (result.path == NULL || result.mode == 0) {
  		giterr_set(GITERR_CHECKOUT, "Could not merge contents of file");
  		error = GIT_EMERGECONFLICT;
  		goto done;
  	}
  
  	if ((error = checkout_merge_path(&path_workdir, data, conflict, &result)) < 0)
  		goto done;
  
  	if ((data->strategy & GIT_CHECKOUT_UPDATE_ONLY) != 0 &&
  		(error = checkout_safe_for_update_only(git_buf_cstr(&path_workdir), result.mode)) <= 0)
  		goto done;
  
  	if (!data->opts.disable_filters) {
  		in_data.ptr = (char *)result.ptr;
  		in_data.size = result.len;
  
  		if ((error = git_filter_list_load(&fl, data->repo, NULL, git_buf_cstr(&path_workdir),
  				GIT_FILTER_TO_WORKTREE, GIT_FILTER_OPT_DEFAULT)) < 0 ||
  			(error = git_filter_list_apply_to_data(&out_data, fl, &in_data)) < 0)
  			goto done;
  	} else {
  		out_data.ptr = (char *)result.ptr;
  		out_data.size = result.len;
  	}
  
  	if ((error = git_futils_mkpath2file(path_workdir.ptr, 0755)) < 0 ||
  		(error = git_filebuf_open(&output, git_buf_cstr(&path_workdir), GIT_FILEBUF_DO_NOT_BUFFER, result.mode)) < 0 ||
  		(error = git_filebuf_write(&output, out_data.ptr, out_data.size)) < 0 ||
  		(error = git_filebuf_commit(&output)) < 0)
  		goto done;
  
  done:
  	git_filter_list_free(fl);
  
  	git_buf_free(&out_data);
  	git_buf_free(&our_label);
  	git_buf_free(&their_label);
  
  	git_merge_file_result_free(&result);
  	git_buf_free(&path_workdir);
  	git_buf_free(&path_suffixed);
  
  	return error;
  }
  
  static int checkout_conflict_add(
  	checkout_data *data,
  	const git_index_entry *conflict)
  {
  	int error = git_index_remove(data->index, conflict->path, 0);
  
  	if (error == GIT_ENOTFOUND)
  		giterr_clear();
  	else if (error < 0)
  		return error;
  
  	return git_index_add(data->index, conflict);
  }
  
  static int checkout_conflict_update_index(
  	checkout_data *data,
  	checkout_conflictdata *conflict)
  {
  	int error = 0;
  
  	if (conflict->ancestor)
  		error = checkout_conflict_add(data, conflict->ancestor);
  
  	if (!error && conflict->ours)
  		error = checkout_conflict_add(data, conflict->ours);
  
  	if (!error && conflict->theirs)
  		error = checkout_conflict_add(data, conflict->theirs);
  
  	return error;
  }
  
  static int checkout_create_conflicts(checkout_data *data)
  {
  	checkout_conflictdata *conflict;
  	size_t i;
  	int error = 0;
  
  	git_vector_foreach(&data->update_conflicts, i, conflict) {
  
  		/* Both deleted: nothing to do */
  		if (conflict->ours == NULL && conflict->theirs == NULL)
  			error = 0;
  
  		else if ((data->strategy & GIT_CHECKOUT_USE_OURS) &&
  			conflict->ours)
  			error = checkout_write_entry(data, conflict, conflict->ours);
  		else if ((data->strategy & GIT_CHECKOUT_USE_THEIRS) &&
  			conflict->theirs)
  			error = checkout_write_entry(data, conflict, conflict->theirs);
  
  		/* Ignore the other side of name collisions. */
  		else if ((data->strategy & GIT_CHECKOUT_USE_OURS) &&
  			!conflict->ours && conflict->name_collision)
  			error = 0;
  		else if ((data->strategy & GIT_CHECKOUT_USE_THEIRS) &&
  			!conflict->theirs && conflict->name_collision)
  			error = 0;
  
  		/* For modify/delete, name collisions and d/f conflicts, write
  		 * the file (potentially with the name mangled.
  		 */
  		else if (conflict->ours != NULL && conflict->theirs == NULL)
  			error = checkout_write_entry(data, conflict, conflict->ours);
  		else if (conflict->ours == NULL && conflict->theirs != NULL)
  			error = checkout_write_entry(data, conflict, conflict->theirs);
  
  		/* Add/add conflicts and rename 1->2 conflicts, write the
  		 * ours/theirs sides (potentially name mangled).
  		 */
  		else if (conflict->one_to_two)
  			error = checkout_write_entries(data, conflict);
  
  		/* If all sides are links, write the ours side */
  		else if (S_ISLNK(conflict->ours->mode) &&
  			S_ISLNK(conflict->theirs->mode))
  			error = checkout_write_entry(data, conflict, conflict->ours);
  		/* Link/file conflicts, write the file side */
  		else if (S_ISLNK(conflict->ours->mode))
  			error = checkout_write_entry(data, conflict, conflict->theirs);
  		else if (S_ISLNK(conflict->theirs->mode))
  			error = checkout_write_entry(data, conflict, conflict->ours);
  
  		/* If any side is a gitlink, do nothing. */
  		else if (conflict->submodule)
  			error = 0;
  
  		/* If any side is binary, write the ours side */
  		else if (conflict->binary)
  			error = checkout_write_entry(data, conflict, conflict->ours);
  
  		else if (!error)
  			error = checkout_write_merge(data, conflict);
  
  		/* Update the index extensions (REUC and NAME) if we're checking
  		 * out a different index. (Otherwise just leave them there.)
  		 */
  		if (!error && (data->strategy & GIT_CHECKOUT_DONT_UPDATE_INDEX) == 0)
  			error = checkout_conflict_update_index(data, conflict);
  
  		if (error)
  			break;
  
  		data->completed_steps++;
  		report_progress(data,
  			conflict->ours ? conflict->ours->path :
  			(conflict->theirs ? conflict->theirs->path : conflict->ancestor->path));
  	}
  
  	return error;
  }
  
  static int checkout_remove_conflicts(checkout_data *data)
  {
  	const char *conflict;
  	size_t i;
  
  	git_vector_foreach(&data->remove_conflicts, i, conflict) {
  		if (git_index_conflict_remove(data->index, conflict) < 0)
  			return -1;
  
  		data->completed_steps++;
  	}
  
  	return 0;
  }
  
  static int checkout_extensions_update_index(checkout_data *data)
  {
  	const git_index_reuc_entry *reuc_entry;
  	const git_index_name_entry *name_entry;
  	size_t i;
  	int error = 0;
  
  	if ((data->strategy & GIT_CHECKOUT_UPDATE_ONLY) != 0)
  		return 0;
  
  	if (data->update_reuc) {
  		git_vector_foreach(data->update_reuc, i, reuc_entry) {
  			if ((error = git_index_reuc_add(data->index, reuc_entry->path,
  				reuc_entry->mode[0], &reuc_entry->oid[0],
  				reuc_entry->mode[1], &reuc_entry->oid[1],
  				reuc_entry->mode[2], &reuc_entry->oid[2])) < 0)
  				goto done;
  		}
  	}
  
  	if (data->update_names) {
  		git_vector_foreach(data->update_names, i, name_entry) {
  			if ((error = git_index_name_add(data->index, name_entry->ancestor,
  				name_entry->ours, name_entry->theirs)) < 0)
  				goto done;
  		}
  	}
  
  done:
  	return error;
  }
  
  static void checkout_data_clear(checkout_data *data)
  {
  	if (data->opts_free_baseline) {
  		git_tree_free(data->opts.baseline);
  		data->opts.baseline = NULL;
  	}
  
  	git_vector_free(&data->removes);
  	git_pool_clear(&data->pool);
  
  	git_vector_free_deep(&data->remove_conflicts);
  	git_vector_free_deep(&data->update_conflicts);
  
  	git__free(data->pfx);
  	data->pfx = NULL;
  
  	git_buf_free(&data->path);
  	git_buf_free(&data->tmp);
  
  	git_index_free(data->index);
  	data->index = NULL;
  }
  
  static int checkout_data_init(
  	checkout_data *data,
  	git_iterator *target,
  	const git_checkout_options *proposed)
  {
  	int error = 0;
  	git_repository *repo = git_iterator_owner(target);
  
  	memset(data, 0, sizeof(*data));
  
  	if (!repo) {
  		giterr_set(GITERR_CHECKOUT, "Cannot checkout nothing");
  		return -1;
  	}
  
  	if ((!proposed || !proposed->target_directory) &&
  		(error = git_repository__ensure_not_bare(repo, "checkout")) < 0)
  		return error;
  
  	data->repo = repo;
  	data->target = target;
  
  	GITERR_CHECK_VERSION(
  		proposed, GIT_CHECKOUT_OPTIONS_VERSION, "git_checkout_options");
  
  	if (!proposed)
  		GIT_INIT_STRUCTURE(&data->opts, GIT_CHECKOUT_OPTIONS_VERSION);
  	else
  		memmove(&data->opts, proposed, sizeof(git_checkout_options));
  
  	if (!data->opts.target_directory)
  		data->opts.target_directory = git_repository_workdir(repo);
  	else if (!git_path_isdir(data->opts.target_directory) &&
  			 (error = git_futils_mkdir(data->opts.target_directory, NULL,
  					GIT_DIR_MODE, GIT_MKDIR_VERIFY_DIR)) < 0)
  		goto cleanup;
  
  	/* refresh config and index content unless NO_REFRESH is given */
  	if ((data->opts.checkout_strategy & GIT_CHECKOUT_NO_REFRESH) == 0) {
  		git_config *cfg;
  
  		if ((error = git_repository_config__weakptr(&cfg, repo)) < 0)
  			goto cleanup;
  
  		/* Get the repository index and reload it (unless we're checking
  		 * out the index; then it has the changes we're trying to check
  		 * out and those should not be overwritten.)
  		 */
  		if ((error = git_repository_index(&data->index, data->repo)) < 0)
  			goto cleanup;
  
  		if (data->index != git_iterator_get_index(target)) {
  			if ((error = git_index_read(data->index, true)) < 0)
  				goto cleanup;
  
  			/* cannot checkout if unresolved conflicts exist */
  			if ((data->opts.checkout_strategy & GIT_CHECKOUT_FORCE) == 0 &&
  				git_index_has_conflicts(data->index)) {
  				error = GIT_EMERGECONFLICT;
  				giterr_set(GITERR_CHECKOUT,
  					"unresolved conflicts exist in the index");
  				goto cleanup;
  			}
  
  			/* clean conflict data in the current index */
  			git_index_name_clear(data->index);
  			git_index_reuc_clear(data->index);
  		}
  	}
  
  	/* if you are forcing, definitely allow safe updates */
  	if ((data->opts.checkout_strategy & GIT_CHECKOUT_FORCE) != 0)
  		data->opts.checkout_strategy |= GIT_CHECKOUT_SAFE_CREATE;
  	if ((data->opts.checkout_strategy & GIT_CHECKOUT_SAFE_CREATE) != 0)
  		data->opts.checkout_strategy |= GIT_CHECKOUT_SAFE;
  
  	data->strategy = data->opts.checkout_strategy;
  
  	/* opts->disable_filters is false by default */
  
  	if (!data->opts.dir_mode)
  		data->opts.dir_mode = GIT_DIR_MODE;
  
  	if (!data->opts.file_open_flags)
  		data->opts.file_open_flags = O_CREAT | O_TRUNC | O_WRONLY;
  
  	data->pfx = git_pathspec_prefix(&data->opts.paths);
  
  	if ((error = git_repository__cvar(
  			 &data->can_symlink, repo, GIT_CVAR_SYMLINKS)) < 0)
  		goto cleanup;
  
  	if (!data->opts.baseline) {
  		data->opts_free_baseline = true;
  
  		error = checkout_lookup_head_tree(&data->opts.baseline, repo);
  
  		if (error == GIT_EUNBORNBRANCH) {
  			error = 0;
  			giterr_clear();
  		}
  
  		if (error < 0)
  			goto cleanup;
  	}
  
  	if ((data->opts.checkout_strategy &
  		(GIT_CHECKOUT_CONFLICT_STYLE_MERGE | GIT_CHECKOUT_CONFLICT_STYLE_DIFF3)) == 0) {
  		const char *conflict_style;
  		git_config *cfg = NULL;
  
  		if ((error = git_repository_config__weakptr(&cfg, repo)) < 0 ||
  			(error = git_config_get_string(&conflict_style, cfg, "merge.conflictstyle")) < 0 ||
  			error == GIT_ENOTFOUND)
  			;
  		else if (error)
  			goto cleanup;
  		else if (strcmp(conflict_style, "merge") == 0)
  			data->opts.checkout_strategy |= GIT_CHECKOUT_CONFLICT_STYLE_MERGE;
  		else if (strcmp(conflict_style, "diff3") == 0)
  			data->opts.checkout_strategy |= GIT_CHECKOUT_CONFLICT_STYLE_DIFF3;
  		else {
  			giterr_set(GITERR_CHECKOUT, "unknown style '%s' given for 'merge.conflictstyle'",
  				conflict_style);
  			error = -1;
  			goto cleanup;
  		}
  	}
  
  	if ((error = git_vector_init(&data->removes, 0, git__strcmp_cb)) < 0 ||
  		(error = git_vector_init(&data->remove_conflicts, 0, NULL)) < 0 ||
  		(error = git_vector_init(&data->update_conflicts, 0, NULL)) < 0 ||
  		(error = git_pool_init(&data->pool, 1, 0)) < 0 ||
  		(error = git_buf_puts(&data->path, data->opts.target_directory)) < 0 ||
  		(error = git_path_to_dir(&data->path)) < 0)
  		goto cleanup;
  
  	data->workdir_len = git_buf_len(&data->path);
  
  cleanup:
  	if (error < 0)
  		checkout_data_clear(data);
  
  	return error;
  }
  
  int git_checkout_iterator(
  	git_iterator *target,
  	git_index *index,
  	const git_checkout_options *opts)
  {
  	int error = 0;
  	git_iterator *baseline = NULL, *workdir = NULL;
  	checkout_data data = {0};
  	git_diff_options diff_opts = GIT_DIFF_OPTIONS_INIT;
  	uint32_t *actions = NULL;
  	size_t *counts = NULL;
  	git_iterator_flag_t iterflags = 0;
  
  	/* initialize structures and options */
  	error = checkout_data_init(&data, target, opts);
  	if (error < 0)
  		return error;
  
  	diff_opts.flags =
  		GIT_DIFF_INCLUDE_UNMODIFIED |
  		GIT_DIFF_INCLUDE_UNREADABLE |
  		GIT_DIFF_INCLUDE_UNTRACKED |
  		GIT_DIFF_RECURSE_UNTRACKED_DIRS | /* needed to match baseline */
  		GIT_DIFF_INCLUDE_IGNORED |
  		GIT_DIFF_INCLUDE_TYPECHANGE |
  		GIT_DIFF_INCLUDE_TYPECHANGE_TREES |
  		GIT_DIFF_SKIP_BINARY_CHECK;
  	if (data.opts.checkout_strategy & GIT_CHECKOUT_DISABLE_PATHSPEC_MATCH)
  		diff_opts.flags |= GIT_DIFF_DISABLE_PATHSPEC_MATCH;
  	if (data.opts.paths.count > 0)
  		diff_opts.pathspec = data.opts.paths;
  
  	/* set up iterators */
  
  	iterflags = git_iterator_ignore_case(target) ?
  		GIT_ITERATOR_IGNORE_CASE : GIT_ITERATOR_DONT_IGNORE_CASE;
  
  	if ((error = git_iterator_reset(target, data.pfx, data.pfx)) < 0 ||
  		(error = git_iterator_for_workdir_ext(
  			&workdir, data.repo, data.opts.target_directory, index, NULL,
  			iterflags | GIT_ITERATOR_DONT_AUTOEXPAND,
  			data.pfx, data.pfx)) < 0 ||
  		(error = git_iterator_for_tree(
  			&baseline, data.opts.baseline,
  			iterflags, data.pfx, data.pfx)) < 0)
  		goto cleanup;
  
  	/* Should not have case insensitivity mismatch */
  	assert(git_iterator_ignore_case(workdir) == git_iterator_ignore_case(baseline));
  
  	/* Generate baseline-to-target diff which will include an entry for
  	 * every possible update that might need to be made.
  	 */
  	if ((error = git_diff__from_iterators(
  			&data.diff, data.repo, baseline, target, &diff_opts)) < 0)
  		goto cleanup;
  
  	/* Loop through diff (and working directory iterator) building a list of
  	 * actions to be taken, plus look for conflicts and send notifications,
  	 * then loop through conflicts.
  	 */
  	if ((error = checkout_get_actions(&actions, &counts, &data, workdir)) != 0)
  		goto cleanup;
  
  	data.total_steps = counts[CHECKOUT_ACTION__REMOVE] +
  		counts[CHECKOUT_ACTION__REMOVE_CONFLICT] +
  		counts[CHECKOUT_ACTION__UPDATE_BLOB] +
  		counts[CHECKOUT_ACTION__UPDATE_SUBMODULE] +
  		counts[CHECKOUT_ACTION__UPDATE_CONFLICT];
  
  	report_progress(&data, NULL); /* establish 0 baseline */
  
  	/* To deal with some order dependencies, perform remaining checkout
  	 * in three passes: removes, then update blobs, then update submodules.
  	 */
  	if (counts[CHECKOUT_ACTION__REMOVE] > 0 &&
  		(error = checkout_remove_the_old(actions, &data)) < 0)
  		goto cleanup;
  
  	if (counts[CHECKOUT_ACTION__REMOVE_CONFLICT] > 0 &&
  		(error = checkout_remove_conflicts(&data)) < 0)
  		goto cleanup;
  
  	if (counts[CHECKOUT_ACTION__UPDATE_BLOB] > 0 &&
  		(error = checkout_create_the_new(actions, &data)) < 0)
  		goto cleanup;
  
  	if (counts[CHECKOUT_ACTION__UPDATE_SUBMODULE] > 0 &&
  		(error = checkout_create_submodules(actions, &data)) < 0)
  		goto cleanup;
  
  	if (counts[CHECKOUT_ACTION__UPDATE_CONFLICT] > 0 &&
  		(error = checkout_create_conflicts(&data)) < 0)
  		goto cleanup;
  
  	if (data.index != git_iterator_get_index(target) &&
  		(error = checkout_extensions_update_index(&data)) < 0)
  		goto cleanup;
  
  	assert(data.completed_steps == data.total_steps);
  
  cleanup:
  	if (!error && data.index != NULL &&
  		(data.strategy & GIT_CHECKOUT_DONT_UPDATE_INDEX) == 0)
  		error = git_index_write(data.index);
  
  	git_diff_free(data.diff);
  	git_iterator_free(workdir);
  	git_iterator_free(baseline);
  	git__free(actions);
  	git__free(counts);
  	checkout_data_clear(&data);
  
  	return error;
  }
  
  int git_checkout_index(
  	git_repository *repo,
  	git_index *index,
  	const git_checkout_options *opts)
  {
  	int error, owned = 0;
  	git_iterator *index_i;
  
  	if (!index && !repo) {
  		giterr_set(GITERR_CHECKOUT,
  			"Must provide either repository or index to checkout");
  		return -1;
  	}
  
  	if (index && repo &&
  		git_index_owner(index) &&
  		git_index_owner(index) != repo) {
  		giterr_set(GITERR_CHECKOUT,
  			"Index to checkout does not match repository");
  		return -1;
  	} else if(index && repo && !git_index_owner(index)) {
  		GIT_REFCOUNT_OWN(index, repo);
  		owned = 1;
  	}
  
  	if (!repo)
  		repo = git_index_owner(index);
  
  	if (!index && (error = git_repository_index__weakptr(&index, repo)) < 0)
  		return error;
  	GIT_REFCOUNT_INC(index);
  
  	if (!(error = git_iterator_for_index(&index_i, index, 0, NULL, NULL)))
  		error = git_checkout_iterator(index_i, index, opts);
  
  	if (owned)
  		GIT_REFCOUNT_OWN(index, NULL);
  
  	git_iterator_free(index_i);
  	git_index_free(index);
  
  	return error;
  }
  
  int git_checkout_tree(
  	git_repository *repo,
  	const git_object *treeish,
  	const git_checkout_options *opts)
  {
  	int error;
  	git_index *index;
  	git_tree *tree = NULL;
  	git_iterator *tree_i = NULL;
  
  	if (!treeish && !repo) {
  		giterr_set(GITERR_CHECKOUT,
  			"Must provide either repository or tree to checkout");
  		return -1;
  	}
  	if (treeish && repo && git_object_owner(treeish) != repo) {
  		giterr_set(GITERR_CHECKOUT,
  			"Object to checkout does not match repository");
  		return -1;
  	}
  
  	if (!repo)
  		repo = git_object_owner(treeish);
  
  	if (treeish) {
  		if (git_object_peel((git_object **)&tree, treeish, GIT_OBJ_TREE) < 0) {
  			giterr_set(
  				GITERR_CHECKOUT, "Provided object cannot be peeled to a tree");
  			return -1;
  		}
  	}
  	else {
  		if ((error = checkout_lookup_head_tree(&tree, repo)) < 0) {
  			if (error != GIT_EUNBORNBRANCH)
  				giterr_set(
  					GITERR_CHECKOUT,
  					"HEAD could not be peeled to a tree and no treeish given");
  			return error;
  		}
  	}
  
  	if ((error = git_repository_index(&index, repo)) < 0)
  		return error;
  
  	if (!(error = git_iterator_for_tree(&tree_i, tree, 0, NULL, NULL)))
  		error = git_checkout_iterator(tree_i, index, opts);
  
  	git_iterator_free(tree_i);
  	git_index_free(index);
  	git_tree_free(tree);
  
  	return error;
  }
  
  int git_checkout_head(
  	git_repository *repo,
  	const git_checkout_options *opts)
  {
  	assert(repo);
  	return git_checkout_tree(repo, NULL, opts);
  }
  
  int git_checkout_init_options(git_checkout_options *opts, unsigned int version)
  {
  	GIT_INIT_STRUCTURE_FROM_TEMPLATE(
  		opts, version, git_checkout_options, GIT_CHECKOUT_OPTIONS_INIT);
  	return 0;
  }
  