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thodg/got/lib/worktree.c

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  • Author : Stefan Sperling
    Date : 2019-01-13 17:15:53
    Hash : 5d56da81
    Message : happy new copyright year

  • lib/worktree.c
  • /*
     * Copyright (c) 2018, 2019 Stefan Sperling <stsp@openbsd.org>
     *
     * Permission to use, copy, modify, and distribute this software for any
     * purpose with or without fee is hereby granted, provided that the above
     * copyright notice and this permission notice appear in all copies.
     *
     * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
     * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
     * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     */
    
    #include <sys/stat.h>
    #include <sys/limits.h>
    #include <sys/queue.h>
    #include <sys/tree.h>
    
    #include <stddef.h>
    #include <string.h>
    #include <stdio.h>
    #include <stdlib.h>
    #include <fcntl.h>
    #include <errno.h>
    #include <unistd.h>
    #include <sha1.h>
    #include <zlib.h>
    #include <fnmatch.h>
    #include <libgen.h>
    
    #include "got_error.h"
    #include "got_repository.h"
    #include "got_reference.h"
    #include "got_object.h"
    #include "got_worktree.h"
    #include "got_opentemp.h"
    
    #include "got_lib_worktree.h"
    #include "got_lib_path.h"
    #include "got_lib_sha1.h"
    #include "got_lib_fileindex.h"
    #include "got_lib_inflate.h"
    #include "got_lib_delta.h"
    #include "got_lib_object.h"
    
    #ifndef MIN
    #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
    #endif
    
    static const struct got_error *
    create_meta_file(const char *path_got, const char *name, const char *content)
    {
    	const struct got_error *err = NULL;
    	char *path;
    	int fd = -1;
    
    	if (asprintf(&path, "%s/%s", path_got, name) == -1) {
    		err = got_error_from_errno();
    		path = NULL;
    		goto done;
    	}
    
    	fd = open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW,
    	    GOT_DEFAULT_FILE_MODE);
    	if (fd == -1) {
    		err = got_error_from_errno();
    		goto done;
    	}
    
    	if (content) {
    		int len = dprintf(fd, "%s\n", content);
    		if (len != strlen(content) + 1) {
    			err = got_error_from_errno();
    			goto done;
    		}
    	}
    
    done:
    	if (fd != -1 && close(fd) == -1 && err == NULL)
    		err = got_error_from_errno();
    	free(path);
    	return err;
    }
    
    static const struct got_error *
    update_meta_file(const char *path_got, const char *name, const char *content)
    {
    	const struct got_error *err = NULL;
    	FILE *tmpfile = NULL;
    	char *tmppath = NULL;
    	char *path = NULL;
    
    	if (asprintf(&path, "%s/%s", path_got, name) == -1) {
    		err = got_error_from_errno();
    		path = NULL;
    		goto done;
    	}
    
    	err = got_opentemp_named(&tmppath, &tmpfile, path);
    	if (err)
    		goto done;
    
    	if (content) {
    		int len = fprintf(tmpfile, "%s\n", content);
    		if (len != strlen(content) + 1) {
    			err = got_error_from_errno();
    			goto done;
    		}
    	}
    
    	if (rename(tmppath, path) != 0) {
    		err = got_error_from_errno();
    		goto done;
    	}
    
    done:
    	free(tmppath);
    	fclose(tmpfile);
    	return err;
    }
    
    static const struct got_error *
    read_meta_file(char **content, const char *path_got, const char *name)
    {
    	const struct got_error *err = NULL;
    	char *path;
    	int fd = -1;
    	ssize_t n;
    	struct stat sb;
    
    	*content = NULL;
    
    	if (asprintf(&path, "%s/%s", path_got, name) == -1) {
    		err = got_error_from_errno();
    		path = NULL;
    		goto done;
    	}
    
    	fd = open(path, O_RDONLY | O_NOFOLLOW);
    	if (fd == -1) {
    		err = got_error_from_errno();
    		goto done;
    	}
    	if (flock(fd, LOCK_SH | LOCK_NB) == -1) {
    		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
    		    : got_error_from_errno());
    		goto done;
    	}
    
    	stat(path, &sb);
    	*content = calloc(1, sb.st_size);
    	if (*content == NULL) {
    		err = got_error_from_errno();
    		goto done;
    	}
    
    	n = read(fd, *content, sb.st_size);
    	if (n != sb.st_size) {
    		err = (n == -1 ? got_error_from_errno() :
    		    got_error(GOT_ERR_WORKTREE_META));
    		goto done;
    	}
    	if ((*content)[sb.st_size - 1] != '\n') {
    		err = got_error(GOT_ERR_WORKTREE_META);
    		goto done;
    	}
    	(*content)[sb.st_size - 1] = '\0';
    
    done:
    	if (fd != -1 && close(fd) == -1 && err == NULL)
    		err = got_error_from_errno();
    	free(path);
    	if (err) {
    		free(*content);
    		*content = NULL;
    	}
    	return err;
    }
    
    const struct got_error *
    got_worktree_init(const char *path, struct got_reference *head_ref,
        const char *prefix, struct got_repository *repo)
    {
    	const struct got_error *err = NULL;
    	struct got_object_id *commit_id = NULL;
    	int obj_type;
    	char *path_got = NULL;
    	char *refstr = NULL;
    	char *formatstr = NULL;
    	char *absprefix = NULL;
    	char *basestr = NULL;
    
    	err = got_ref_resolve(&commit_id, repo, head_ref);
    	if (err)
    		return err;
    	err = got_object_get_type(&obj_type, repo, commit_id);
    	if (err)
    		return err;
    	if (obj_type != GOT_OBJ_TYPE_COMMIT)
    		return got_error(GOT_ERR_OBJ_TYPE);
    
    	if (!got_path_is_absolute(prefix)) {
    		if (asprintf(&absprefix, "/%s", prefix) == -1)
    			return got_error_from_errno();
    	}
    
    	/* Create top-level directory (may already exist). */
    	if (mkdir(path, GOT_DEFAULT_DIR_MODE) == -1 && errno != EEXIST) {
    		err = got_error_from_errno();
    		goto done;
    	}
    
    	/* Create .got directory (may already exist). */
    	if (asprintf(&path_got, "%s/%s", path, GOT_WORKTREE_GOT_DIR) == -1) {
    		err = got_error_from_errno();
    		goto done;
    	}
    	if (mkdir(path_got, GOT_DEFAULT_DIR_MODE) == -1 && errno != EEXIST) {
    		err = got_error_from_errno();
    		goto done;
    	}
    
    	/* Create an empty lock file. */
    	err = create_meta_file(path_got, GOT_WORKTREE_LOCK, NULL);
    	if (err)
    		goto done;
    
    	/* Create an empty file index. */
    	err = create_meta_file(path_got, GOT_WORKTREE_FILE_INDEX, NULL);
    	if (err)
    		goto done;
    
    	/* Write the HEAD reference. */
    	refstr = got_ref_to_str(head_ref);
    	if (refstr == NULL) {
    		err = got_error_from_errno();
    		goto done;
    	}
    	err = create_meta_file(path_got, GOT_WORKTREE_HEAD_REF, refstr);
    	if (err)
    		goto done;
    
    	/* Record our base commit. */
    	err = got_object_id_str(&basestr, commit_id);
    	if (err)
    		goto done;
    	err = create_meta_file(path_got, GOT_WORKTREE_BASE_COMMIT, basestr);
    	if (err)
    		goto done;
    
    	/* Store path to repository. */
    	err = create_meta_file(path_got, GOT_WORKTREE_REPOSITORY,
    	    got_repo_get_path(repo));
    	if (err)
    		goto done;
    
    	/* Store in-repository path prefix. */
    	err = create_meta_file(path_got, GOT_WORKTREE_PATH_PREFIX,
    	    absprefix ? absprefix : prefix);
    	if (err)
    		goto done;
    
    	/* Stamp work tree with format file. */
    	if (asprintf(&formatstr, "%d", GOT_WORKTREE_FORMAT_VERSION) == -1) {
    		err = got_error_from_errno();
    		goto done;
    	}
    	err = create_meta_file(path_got, GOT_WORKTREE_FORMAT, formatstr);
    	if (err)
    		goto done;
    
    done:
    	free(commit_id);
    	free(path_got);
    	free(formatstr);
    	free(refstr);
    	free(absprefix);
    	free(basestr);
    	return err;
    }
    
    const struct got_error *
    got_worktree_open(struct got_worktree **worktree, const char *path)
    {
    	const struct got_error *err = NULL;
    	char *path_got;
    	char *formatstr = NULL;
    	char *path_lock = NULL;
    	char *base_commit_id_str = NULL;
    	char *head_ref_str = NULL;
    	int version, fd = -1;
    	const char *errstr;
    	struct got_repository *repo = NULL;
    
    	*worktree = NULL;
    
    	if (asprintf(&path_got, "%s/%s", path, GOT_WORKTREE_GOT_DIR) == -1) {
    		err = got_error_from_errno();
    		path_got = NULL;
    		goto done;
    	}
    
    	if (asprintf(&path_lock, "%s/%s", path_got, GOT_WORKTREE_LOCK) == -1) {
    		err = got_error_from_errno();
    		path_lock = NULL;
    		goto done;
    	}
    
    	fd = open(path_lock, O_RDWR | O_EXLOCK | O_NONBLOCK);
    	if (fd == -1) {
    		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
    		    : got_error_from_errno());
    		goto done;
    	}
    
    	err = read_meta_file(&formatstr, path_got, GOT_WORKTREE_FORMAT);
    	if (err)
    		goto done;
    
    	version = strtonum(formatstr, 1, INT_MAX, &errstr);
    	if (errstr) {
    		err = got_error(GOT_ERR_WORKTREE_META);
    		goto done;
    	}
    	if (version != GOT_WORKTREE_FORMAT_VERSION) {
    		err = got_error(GOT_ERR_WORKTREE_VERS);
    		goto done;
    	}
    
    	*worktree = calloc(1, sizeof(**worktree));
    	if (*worktree == NULL) {
    		err = got_error_from_errno();
    		goto done;
    	}
    	(*worktree)->lockfd = -1;
    
    	(*worktree)->root_path = strdup(path);
    	if ((*worktree)->root_path == NULL) {
    		err = got_error_from_errno();
    		goto done;
    	}
    	err = read_meta_file(&(*worktree)->repo_path, path_got,
    	    GOT_WORKTREE_REPOSITORY);
    	if (err)
    		goto done;
    
    	err = read_meta_file(&(*worktree)->path_prefix, path_got,
    	    GOT_WORKTREE_PATH_PREFIX);
    	if (err)
    		goto done;
    
    	err = read_meta_file(&base_commit_id_str, path_got,
    	    GOT_WORKTREE_BASE_COMMIT);
    	if (err)
    		goto done;
    
    	err = got_repo_open(&repo, (*worktree)->repo_path);
    	if (err)
    		goto done;
    
    	err = got_object_resolve_id_str(&(*worktree)->base_commit_id, repo,
    	    base_commit_id_str);
    	if (err)
    		goto done;
    
    	err = read_meta_file(&head_ref_str, path_got, GOT_WORKTREE_HEAD_REF);
    	if (err)
    		goto done;
    
    	err = got_ref_open(&(*worktree)->head_ref, repo, head_ref_str);
    done:
    	if (repo)
    		got_repo_close(repo);
    	free(path_got);
    	free(path_lock);
    	free(head_ref_str);
    	free(base_commit_id_str);
    	if (err) {
    		if (fd != -1)
    			close(fd);
    		if (*worktree != NULL)
    			got_worktree_close(*worktree);
    		*worktree = NULL;
    	} else
    		(*worktree)->lockfd = fd;
    
    	return err;
    }
    
    void
    got_worktree_close(struct got_worktree *worktree)
    {
    	free(worktree->root_path);
    	free(worktree->repo_path);
    	free(worktree->path_prefix);
    	free(worktree->base_commit_id);
    	if (worktree->head_ref)
    		got_ref_close(worktree->head_ref);
    	if (worktree->lockfd != -1)
    		close(worktree->lockfd);
    	free(worktree);
    }
    
    const char *
    got_worktree_get_repo_path(struct got_worktree *worktree)
    {
    	return worktree->repo_path;
    }
    
    const char *
    got_worktree_get_path_prefix(struct got_worktree *worktree)
    {
    	return worktree->path_prefix;
    }
    
    const struct got_error *
    got_worktree_match_path_prefix(int *match, struct got_worktree *worktree,
        const char *path_prefix)
    {
    	char *absprefix = NULL;
    
    	if (!got_path_is_absolute(path_prefix)) {
    		if (asprintf(&absprefix, "/%s", path_prefix) == -1)
    			return got_error_from_errno();
    	}
    	*match = (strcmp(absprefix ? absprefix : path_prefix,
    	    worktree->path_prefix) == 0);
    	free(absprefix);
    	return NULL;
    }
    
    char *
    got_worktree_get_head_ref_name(struct got_worktree *worktree)
    {
    	return got_ref_to_str(worktree->head_ref);
    }
    
    struct got_reference *
    got_worktree_get_head_ref(struct got_worktree *worktree)
    {
    	return got_ref_dup(worktree->head_ref);
    }
    
    const struct got_object_id *
    got_worktree_get_base_commit_id(struct got_worktree *worktree)
    {
    	return worktree->base_commit_id;
    }
    
    const struct got_error *
    got_worktree_set_base_commit_id(struct got_worktree *worktree,
        struct got_repository *repo, struct got_object_id *commit_id)
    {
    	const struct got_error *err;
    	struct got_object *obj = NULL;
    	char *id_str = NULL;
    	char *path_got = NULL;
    
    	if (asprintf(&path_got, "%s/%s", worktree->root_path,
    	    GOT_WORKTREE_GOT_DIR) == -1) {
    		err = got_error_from_errno();
    		path_got = NULL;
    		goto done;
    	}
    
    	err = got_object_open(&obj, repo, commit_id);
    	if (err)
    		return err;
    
    	if (obj->type != GOT_OBJ_TYPE_COMMIT) {
    		err = got_error(GOT_ERR_OBJ_TYPE);
    		goto done;
    	}
    
    	/* Record our base commit. */
    	err = got_object_id_str(&id_str, commit_id);
    	if (err)
    		goto done;
    	err = update_meta_file(path_got, GOT_WORKTREE_BASE_COMMIT, id_str);
    	if (err)
    		goto done;
    
    	free(worktree->base_commit_id);
    	worktree->base_commit_id = got_object_id_dup(commit_id);
    	if (worktree->base_commit_id == NULL) {
    		err = got_error_from_errno();
    		goto done;
    	}
    done:
    	if (obj)
    		got_object_close(obj);
    	free(id_str);
    	free(path_got);
    	return err;
    }
    
    static const struct got_error *
    lock_worktree(struct got_worktree *worktree, int operation)
    {
    	if (flock(worktree->lockfd, operation | LOCK_NB) == -1)
    		return (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
    		    : got_error_from_errno());
    	return NULL;
    }
    
    static const struct got_error *
    make_parent_dirs(const char *abspath)
    {
    	const struct got_error *err = NULL;
    
    	char *parent = dirname(abspath);
    	if (parent == NULL)
    		return NULL;
    
    	if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1) {
    		if (errno == ENOENT) {
    			err = make_parent_dirs(parent);
    			if (err)
    				return err;
    			if (mkdir(parent, GOT_DEFAULT_DIR_MODE) == -1)
    				return got_error_from_errno();
    		} else
    			err = got_error_from_errno();
    	}
    
    	return err;
    }
    
    static const struct got_error *
    add_dir_on_disk(struct got_worktree *worktree, const char *path)
    {
    	const struct got_error *err = NULL;
    	char *abspath;
    
    	if (asprintf(&abspath, "%s/%s", worktree->root_path, path) == -1)
    		return got_error_from_errno();
    
    	/* XXX queue work rather than editing disk directly? */
    	if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1) {
    		struct stat sb;
    
    		if (errno == EEXIST) {
    			if (lstat(abspath, &sb) == -1) {
    				err = got_error_from_errno();
    				goto done;
    			}
    
    			if (!S_ISDIR(sb.st_mode)) {
    				/* TODO directory is obstructed; do something */
    				err = got_error(GOT_ERR_FILE_OBSTRUCTED);
    				goto done;
    			}
    
    			return NULL;
    		} else if (errno == ENOENT) {
    			err = make_parent_dirs(abspath);
    			if (err)
    				goto done;
    			if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1)
    				err = got_error_from_errno();
    		} else
    			err = got_error_from_errno();
    	}
    
    done:
    	free(abspath);
    	return err;
    }
    
    static const struct got_error *
    install_blob(struct got_worktree *worktree, struct got_fileindex *fileindex,
       struct got_fileindex_entry *entry, const char *path,
       struct got_blob_object *blob,
       struct got_repository *repo, got_worktree_checkout_cb progress_cb,
       void *progress_arg)
    {
    	const struct got_error *err = NULL;
    	char *ondisk_path;
    	int fd = -1;
    	size_t len, hdrlen;
    	int update = 0;
    	char *tmppath = NULL;
    
    	if (asprintf(&ondisk_path, "%s/%s", worktree->root_path, path) == -1)
    		return got_error_from_errno();
    
    	fd = open(ondisk_path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW,
    	    GOT_DEFAULT_FILE_MODE);
    	if (fd == -1) {
    		if (errno == ENOENT) {
    			char *parent = dirname(path);
    			if (parent == NULL)
    				return got_error_from_errno();
    			err = add_dir_on_disk(worktree, parent);
    			if (err)
    				return err;
    			fd = open(ondisk_path,
    			    O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW,
    			    GOT_DEFAULT_FILE_MODE);
    			if (fd == -1)
    				return got_error_from_errno();
    		} else if (errno == EEXIST) {
    			struct stat sb;
    			if (lstat(ondisk_path, &sb) == -1) {
    				err = got_error_from_errno();
    				goto done;
    			} else if (!S_ISREG(sb.st_mode)) {
    				/* TODO file is obstructed; do something */
    				err = got_error(GOT_ERR_FILE_OBSTRUCTED);
    				goto done;
    			} else {
    				err = got_opentemp_named_fd(&tmppath, &fd,
    				    ondisk_path);
    				if (err)
    					goto done;
    				update = 1;
    			}
    		} else
    			return got_error_from_errno();
    	}
    
    	(*progress_cb)(progress_arg,
    	    update ? GOT_STATUS_UPDATE : GOT_STATUS_ADD, path);
    
    	hdrlen = got_object_blob_get_hdrlen(blob);
    	do {
    		const uint8_t *buf = got_object_blob_get_read_buf(blob);
    		err = got_object_blob_read_block(&len, blob);
    		if (err)
    			break;
    		if (len > 0) {
    			/* Skip blob object header first time around. */
    			ssize_t outlen = write(fd, buf + hdrlen, len - hdrlen);
    			if (outlen == -1) {
    				err = got_error_from_errno();
    				goto done;
    			} else if (outlen != len - hdrlen) {
    				err = got_error(GOT_ERR_IO);
    				goto done;
    			}
    			hdrlen = 0;
    		}
    	} while (len != 0);
    
    	fsync(fd);
    
    	if (update) {
    		if (rename(tmppath, ondisk_path) != 0) {
    			err = got_error_from_errno();
    			goto done;
    		}
    	}
    
    	if (entry == NULL)
    		entry = got_fileindex_entry_get(fileindex, path);
    	if (entry)
    		err = got_fileindex_entry_update(entry, ondisk_path,
    		    blob->id.sha1, worktree->base_commit_id->sha1);
    	else {
    		err = got_fileindex_entry_alloc(&entry, ondisk_path,
    		    path, blob->id.sha1, worktree->base_commit_id->sha1);
    		if (err)
    			goto done;
    		err = got_fileindex_entry_add(fileindex, entry);
    	}
    done:
    	if (fd != -1)
    		close(fd);
    	free(ondisk_path);
    	free(tmppath);
    	return err;
    }
    
    static const struct got_error *
    update_blob(struct got_worktree *worktree,
        struct got_fileindex *fileindex, struct got_fileindex_entry *ie,
        struct got_tree_entry *te, const char *path,
        struct got_repository *repo, got_worktree_checkout_cb progress_cb,
        void *progress_arg, got_worktree_cancel_cb cancel_cb, void *cancel_arg)
    {
    	const struct got_error *err = NULL;
    	struct got_blob_object *blob = NULL;
    
    	if (ie) {
    		if (memcmp(ie->commit_sha1, worktree->base_commit_id->sha1,
    		    SHA1_DIGEST_LENGTH) == 0) {
    			(*progress_cb)(progress_arg, GOT_STATUS_EXISTS,
    			    path);
    			return NULL;
    		}
    		if (memcmp(ie->blob_sha1,
    		    te->id->sha1, SHA1_DIGEST_LENGTH) == 0)
    			return NULL;
    	}
    
    	err = got_object_open_as_blob(&blob, repo, te->id, 8192);
    	if (err)
    		return err;
    
    	err = install_blob(worktree, fileindex, ie, path, blob, repo,
    	    progress_cb, progress_arg);
    	got_object_blob_close(blob);
    	return err;
    }
    
    static const struct got_error *
    remove_ondisk_file(const char *root_path, const char *path)
    {
    	const struct got_error *err = NULL;
    	char *ondisk_path = NULL;
    
    	if (asprintf(&ondisk_path, "%s/%s", root_path, path) == -1)
    		return got_error_from_errno();
    
    	if (unlink(ondisk_path) == -1) {
    		if (errno != ENOENT)
    			err = got_error_from_errno();
    	} else {
    		char *parent = dirname(ondisk_path);
    		while (parent && strcmp(parent, root_path) != 0) {
    			if (rmdir(parent) == -1) {
    				if (errno != ENOTEMPTY)
    					err = got_error_from_errno();
    				break;
    			}
    			parent = dirname(parent);
    		}
    	}
    	free(ondisk_path);
    	return err;
    }
    
    struct diff_cb_arg {
        struct got_fileindex *fileindex;
        struct got_worktree *worktree;
        struct got_repository *repo;
        got_worktree_checkout_cb progress_cb;
        void *progress_arg;
        got_worktree_cancel_cb cancel_cb;
        void *cancel_arg;
    };
    
    static const struct got_error *
    diff_old_new(void *arg, struct got_fileindex_entry *ie,
        struct got_tree_entry *te, const char *parent_path)
    {
    	struct diff_cb_arg *a = arg;
    
    	return update_blob(a->worktree, a->fileindex, ie, te,
    	    ie->path, a->repo, a->progress_cb, a->progress_arg,
    	    a->cancel_cb, a->cancel_arg);
    }
    
    static const struct got_error *
    diff_old(void *arg, struct got_fileindex_entry *ie, const char *parent_path)
    {
    	const struct got_error *err;
    	struct diff_cb_arg *a = arg;
    
    	(*a->progress_cb)(a->progress_arg, GOT_STATUS_DELETE, ie->path);
    
    	err = remove_ondisk_file(a->worktree->root_path, ie->path);
    	if (err)
    		return err;
    	got_fileindex_entry_remove(a->fileindex, ie);
    	return NULL;
    }
    
    static const struct got_error *
    diff_new(void *arg, struct got_tree_entry *te, const char *parent_path)
    {
    	struct diff_cb_arg *a = arg;
    	const struct got_error *err;
    	char *path;
    
    	if (asprintf(&path, "%s%s%s", parent_path,
    	    parent_path[0] ? "/" : "", te->name)
    	    == -1)
    		return got_error_from_errno();
    
    	if (S_ISDIR(te->mode))
    		err = add_dir_on_disk(a->worktree, path);
    	else
    		err = update_blob(a->worktree, a->fileindex, NULL, te, path,
    		    a->repo, a->progress_cb, a->progress_arg,
    		    a->cancel_cb, a->cancel_arg);
    
    	free(path);
    	return err;
    }
    
    const struct got_error *
    got_worktree_checkout_files(struct got_worktree *worktree,
        struct got_repository *repo, got_worktree_checkout_cb progress_cb,
        void *progress_arg, got_worktree_cancel_cb cancel_cb, void *cancel_arg)
    {
    	const struct got_error *err = NULL, *unlockerr, *checkout_err = NULL;
    	struct got_commit_object *commit = NULL;
    	struct got_object_id *tree_id = NULL;
    	struct got_tree_object *tree = NULL;
    	char *fileindex_path = NULL, *new_fileindex_path = NULL;
    	struct got_fileindex *fileindex = NULL;
    	FILE *index = NULL, *new_index = NULL;
    	struct got_fileindex_diff_cb diff_cb;
    	struct diff_cb_arg arg;
    
    	err = lock_worktree(worktree, LOCK_EX);
    	if (err)
    		return err;
    
    	fileindex = got_fileindex_alloc();
    	if (fileindex == NULL) {
    		err = got_error_from_errno();
    		goto done;
    	}
    
    	if (asprintf(&fileindex_path, "%s/%s/%s", worktree->root_path,
    	    GOT_WORKTREE_GOT_DIR, GOT_WORKTREE_FILE_INDEX) == -1) {
    		err = got_error_from_errno();
    		fileindex_path = NULL;
    		goto done;
    	}
    
    	/*
    	 * Read the file index.
    	 * Checking out files is supposed to be an idempotent operation.
    	 * If the on-disk file index is incomplete we will try to complete it.
    	 */
    	index = fopen(fileindex_path, "rb");
    	if (index == NULL) {
    		if (errno != ENOENT) {
    			err = got_error_from_errno();
    			goto done;
    		}
    	} else {
    		err = got_fileindex_read(fileindex, index);
    		fclose(index);
    		if (err)
    			goto done;
    	}
    
    	err = got_opentemp_named(&new_fileindex_path, &new_index,
    	    fileindex_path);
    	if (err)
    		goto done;
    
    	err = got_object_open_as_commit(&commit, repo,
    	   worktree->base_commit_id);
    	if (err)
    		goto done;
    
    	err = got_object_id_by_path(&tree_id, repo,
    	    worktree->base_commit_id, worktree->path_prefix);
    	if (err)
    		goto done;
    
    	err = got_object_open_as_tree(&tree, repo, tree_id);
    	if (err)
    		goto done;
    
    	diff_cb.diff_old_new = diff_old_new;
    	diff_cb.diff_old = diff_old;
    	diff_cb.diff_new = diff_new;
    	arg.fileindex = fileindex;
    	arg.worktree = worktree;
    	arg.repo = repo;
    	arg.progress_cb = progress_cb;
    	arg.progress_arg = progress_arg;
    	arg.cancel_cb = cancel_cb;
    	arg.cancel_arg = cancel_arg;
    	checkout_err = got_fileindex_diff_tree(fileindex, tree, repo,
    	    &diff_cb, &arg);
    
    	/* Try to sync the fileindex back to disk in any case. */
    	err = got_fileindex_write(fileindex, new_index);
    	if (err)
    		goto done;
    
    	if (rename(new_fileindex_path, fileindex_path) != 0) {
    		err = got_error_from_errno();
    		goto done;
    	}
    
    	free(new_fileindex_path);
    	new_fileindex_path = NULL;
    
    done:
    	if (tree)
    		got_object_tree_close(tree);
    	if (commit)
    		got_object_commit_close(commit);
    	if (new_fileindex_path)
    		unlink(new_fileindex_path);
    	if (new_index)
    		fclose(new_index);
    	free(new_fileindex_path);
    	free(fileindex_path);
    	got_fileindex_free(fileindex);
    	if (checkout_err)
    		err = checkout_err;
    	unlockerr = lock_worktree(worktree, LOCK_SH);
    	if (unlockerr && err == NULL)
    		err = unlockerr;
    	return err;
    }