/*

 * 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 "git2/sys/filter.h"

#include "git2/merge.h"

#include "refs.h"

#include "repository.h"

#include "index.h"

#include "filter.h"

#include "blob.h"

#include "diff.h"

#include "diff_generate.h"

#include "pathspec.h"

#include "buf_text.h"

#include "diff_xdiff.h"

#include "path.h"

#include "attr.h"

#include "pool.h"

#include "strmap.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 target_path;

	size_t target_len;

	git_buf tmp;

	unsigned int strategy;

	int can_symlink;

	bool reload_submodules;

	size_t total_steps;

	size_t completed_steps;

	git_checkout_perfdata perfdata;

	git_strmap *mkdir_map;

	git_attr_session attr_session;

} 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");

	}

}

GIT_INLINE(bool) is_workdir_base_or_new(

	const git_oid *workdir_id,

	const git_diff_file *baseitem,

	const git_diff_file *newitem)

{

	return (git_oid__cmp(&baseitem->id, workdir_id) == 0 ||

		git_oid__cmp(&newitem->id, workdir_id) == 0);

}

GIT_INLINE(bool) is_file_mode_changed(git_filemode_t a, git_filemode_t b)

{

#ifdef GIT_WIN32

	/*

	 * On Win32 we do not support the executable bit; the file will

	 * always be 0100644 on disk, don't bother doing a test.

	 */

	return false;

#else

	return (S_ISREG(a) && S_ISREG(b) && a != b);

#endif

}

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, data->repo, wditem->path, GIT_SUBMODULE_IGNORE_UNSPECIFIED) < 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 the

	 * cache contents match the workdir contents, then we do not need

	 * to examine the working directory directly, instead we can

	 * examine the cache to see if _it_ has been modified.  This allows

	 * us to avoid touching the disk.

	 */

	ie = git_index_get_bypath(data->index, wditem->path, 0);

	if (ie != NULL &&

		git_index_time_eq(&wditem->mtime, &ie->mtime) &&

		wditem->file_size == ie->file_size &&

		!is_file_mode_changed(wditem->mode, ie->mode)) {

		/* The workdir is modified iff the index entry is modified */

		return !is_workdir_base_or_new(&ie->id, baseitem, newitem) ||

			is_file_mode_changed(baseitem->mode, ie->mode);

	}

	/* 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 the workdir item is a directory, it cannot be a modified file */

	if (S_ISDIR(wditem->mode))

		return false;

	if (is_file_mode_changed(baseitem->mode, wditem->mode))

		return true;

	if (git_diff__oid_for_entry(&oid, data->diff, wditem, wditem->mode, NULL) < 0)

		return false;

	/* Allow the checkout if the workdir is not modified *or* if the checkout

	 * target's contents are already in the working directory.

	 */

	return !is_workdir_base_or_new(&oid, baseitem, newitem);

}

#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;

		/* if the file is on disk and doesn't match our mode, force update */

		if (wd &&

			GIT_PERMS_IS_EXEC(wd->mode) !=

			GIT_PERMS_IS_EXEC(delta->new_file.mode))

				*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(RECREATE_MISSING, 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(RECREATE_MISSING, 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 int checkout_target_fullpath(

	git_buf **out, checkout_data *data, const char *path)

{

	git_buf_truncate(&data->target_path, data->target_len);

	if (path && git_buf_puts(&data->target_path, path) < 0)

		return -1;

	*out = &data->target_path;

	return 0;

}

static bool wd_item_is_removable(

	checkout_data *data, const git_index_entry *wd)

{

	git_buf *full;

	if (wd->mode != GIT_FILEMODE_TREE)

		return true;

	if (checkout_target_fullpath(&full, data, wd->path) < 0)

		return false;

	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)

				return git_iterator_advance_into(wditem, workdir);

		}

	}

	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(data, 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(data, 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(

			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 bool checkout_is_empty_dir(checkout_data *data, const char *path)

{

	git_buf *fullpath;

	if (checkout_target_fullpath(&fullpath, data, path) < 0)

		return false;

	return git_path_is_empty_dir(fullpath->ptr);

}

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 (wd->mode != GIT_FILEMODE_COMMIT &&

			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));

		*action = CHECKOUT_ACTION_IF(FORCE, REMOVE_AND_UPDATE, NONE);

		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);

		}

		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_with_wd_dir_empty(

	int *action,

	checkout_data *data,

	const git_diff_delta *delta)

{

	int error = checkout_action_no_wd(action, data, delta);

	/* We can always safely remove an empty directory. */

	if (error == 0 && *action != CHECKOUT_ACTION__NONE)

		*action |= CHECKOUT_ACTION__REMOVE;

	return error;

}

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(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_is_empty_dir(data, wd->path) ?

				checkout_action_with_wd_dir_empty(action, data, delta) :

				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);

	}