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thodg/got/lib/worktree.c

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  • Author : Stefan Sperling
    Date : 2018-11-11 12:52:59
    Hash : 99437157
    Message : abort checkout operations cleanly when Ctrl-C is hit

  • lib/worktree.c
  • /*
     * Copyright (c) 2018 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 <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 "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;
    	char buf[4];
    	ssize_t n;
    
    	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;
    	}
    
    	/* The file should be empty. */
    	n = read(fd, buf, sizeof(buf));
    	if (n != 0) {
    		err = (n == -1 ? got_error_from_errno() :
    		    got_error(GOT_ERR_WORKTREE_EXISTS));
    		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 *
    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;
    	char *path_got = NULL;
    	char *refstr = NULL;
    	char *repo_path = NULL;
    	char *formatstr = NULL;
    	char *absprefix = NULL;
    
    	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, refstr);
    	if (err)
    		goto done;
    
    	/* Store path to repository. */
    	repo_path = got_repo_get_path(repo);
    	if (repo_path == NULL) {
    		err = got_error_from_errno();
    		goto done;
    	}
    	err = create_meta_file(path_got, GOT_WORKTREE_REPOSITORY, repo_path);
    	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(path_got);
    	free(formatstr);
    	free(refstr);
    	free(repo_path);
    	free(absprefix);
    	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;
    	int version, fd = -1;
    	const char *errstr;
    
    	*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(&(*worktree)->head_ref, path_got,
    	    GOT_WORKTREE_HEAD);
    	if (err)
    		goto done;
    
    done:
    	free(path_got);
    	free(path_lock);
    	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);
    	free(worktree->head_ref);
    	if (worktree->lockfd != -1)
    		close(worktree->lockfd);
    	free(worktree);
    }
    
    char *
    got_worktree_get_repo_path(struct got_worktree *worktree)
    {
    	return strdup(worktree->repo_path);
    }
    
    char *
    got_worktree_get_head_ref_name(struct got_worktree *worktree)
    {
    	return strdup(worktree->head_ref);
    }
    
    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 char *
    apply_path_prefix(struct got_worktree *worktree, const char *path)
    {
    	const char *p = path;
    	p += strlen(worktree->path_prefix);
    	if (*p == '/')
    		p++;
    	return p;
    }
    
    static const struct got_error *
    add_file_on_disk(struct got_worktree *worktree, struct got_fileindex *fileindex,
       const char *path, struct got_blob_object *blob, struct got_repository *repo)
    {
    	const struct got_error *err = NULL;
    	char *ondisk_path;
    	int fd;
    	size_t len, hdrlen;
    	struct got_fileindex_entry *entry;
    
    	if (asprintf(&ondisk_path, "%s/%s", worktree->root_path,
    	    apply_path_prefix(worktree, 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) {
    		err = got_error_from_errno();
    		if (errno == EEXIST) {
    			struct stat sb;
    			if (lstat(ondisk_path, &sb) == -1) {
    				err = got_error_from_errno();
    			} else if (!S_ISREG(sb.st_mode)) {
    				/* TODO file is obstructed; do something */
    				err = got_error(GOT_ERR_FILE_OBSTRUCTED);
    			}
    		}
    		return err;
    	}
    
    	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);
    			hdrlen = 0;
    			if (outlen == -1) {
    				err = got_error_from_errno();
    				break;
    			} else if (outlen != len) {
    				err = got_error(GOT_ERR_IO);
    				break;
    			}
    		}
    	} while (len != 0);
    
    	fsync(fd);
    
    	err = got_fileindex_entry_open(&entry, ondisk_path,
    	    apply_path_prefix(worktree, path), blob->id.sha1);
    	if (err)
    		goto done;
    
    	err = got_fileindex_entry_add(fileindex, entry);
    	if (err)
    		goto done;
    done:
    	close(fd);
    	free(ondisk_path);
    	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,
    	    apply_path_prefix(worktree, 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) {
    			err = got_error_from_errno();
    			goto done;
    		}
    
    		if (lstat(abspath, &sb) == -1) {
    			err = got_error_from_errno();
    			goto done;
    		}
    
    		if (!S_ISDIR(sb.st_mode)) {
    			/* TODO directory is obstructed; do something */
    			return got_error(GOT_ERR_FILE_OBSTRUCTED);
    		}
    	}
    
    done:
    	free(abspath);
    	return err;
    }
    
    static const struct got_error *
    tree_checkout(struct got_worktree *, struct got_fileindex *,
        struct got_tree_object *, const char *, struct got_repository *,
        got_worktree_checkout_cb progress_cb, void *progress_arg,
        got_worktree_cancel_cb cancel_cb, void *cancel_arg);
    
    static const struct got_error *
    tree_checkout_entry(struct got_worktree *worktree,
        struct got_fileindex *fileindex, struct got_tree_entry *te,
        const char *parent, 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_object *obj = NULL;
    	struct got_blob_object *blob = NULL;
    	struct got_tree_object *tree = NULL;
    	char *path = NULL;
    	char *progress_path = NULL;
    	size_t len;
    
    	if (parent[0] == '/' && parent[1] == '\0')
    		parent = "";
    	if (asprintf(&path, "%s/%s", parent, te->name) == -1)
    		return got_error_from_errno();
    
    	/* Skip this entry if it is outside of our path prefix. */
    	len = MIN(strlen(worktree->path_prefix), strlen(path));
    	if (strncmp(path, worktree->path_prefix, len) != 0) {
    		free(path);
    		return NULL;
    	}
    
    	err = got_object_open(&obj, repo, te->id);
    	if (err)
    		goto done;
    
    	progress_path = path;
    	if (strncmp(progress_path, worktree->path_prefix, len) == 0)
    		progress_path += len;
    	(*progress_cb)(progress_arg, progress_path);
    
    	switch (got_object_get_type(obj)) {
    	case GOT_OBJ_TYPE_BLOB:
    		if (strlen(worktree->path_prefix) >= strlen(path))
    			break;
    		err = got_object_blob_open(&blob, repo, obj, 8192);
    		if (err)
    			goto done;
    		err = add_file_on_disk(worktree, fileindex, path, blob, repo);
    		break;
    	case GOT_OBJ_TYPE_TREE:
    		err = got_object_tree_open(&tree, repo, obj);
    		if (err)
    			goto done;
    		if (strlen(worktree->path_prefix) < strlen(path)) {
    			err = add_dir_on_disk(worktree, path);
    			if (err)
    				break;
    		}
    		/* XXX infinite recursion possible */
    		err = tree_checkout(worktree, fileindex, tree, path, repo,
    		    progress_cb, progress_arg, cancel_cb, cancel_arg);
    		break;
    	default:
    		break;
    	}
    
    done:
    	if (blob)
    		got_object_blob_close(blob);
    	if (tree)
    		got_object_tree_close(tree);
    	if (obj)
    		got_object_close(obj);
    	free(path);
    	return err;
    }
    
    static const struct got_error *
    tree_checkout(struct got_worktree *worktree,
        struct got_fileindex *fileindex, struct got_tree_object *tree,
        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;
    	const struct got_tree_entries *entries;
    	struct got_tree_entry *te;
    	size_t len;
    
    	/* Skip this tree if it is outside of our path prefix. */
    	len = MIN(strlen(worktree->path_prefix), strlen(path));
    	if (strncmp(path, worktree->path_prefix, len) != 0)
    		return NULL;
    
    	entries = got_object_tree_get_entries(tree);
    	SIMPLEQ_FOREACH(te, &entries->head, entry) {
    		if (cancel_cb) {
    			err = (*cancel_cb)(cancel_arg);
    			if (err)
    				break;
    		}
    		err = tree_checkout_entry(worktree, fileindex, te, path, repo,
    		    progress_cb, progress_arg, cancel_cb, cancel_arg);
    		if (err)
    			break;
    	}
    
    	return err;
    }
    
    const struct got_error *
    got_worktree_checkout_files(struct got_worktree *worktree,
        struct got_reference *head_ref, 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;
    	struct got_object_id *commit_id = NULL;
    	struct got_object *obj = NULL;
    	struct got_commit_object *commit = NULL;
    	struct got_tree_object *tree = NULL;
    	char *fileindex_path = NULL, *new_fileindex_path = NULL;
    	struct got_fileindex *fileindex = NULL;
    	FILE *findex = NULL;
    
    	err = lock_worktree(worktree, LOCK_EX);
    	if (err)
    		return err;
    
    	fileindex = got_fileindex_open();
    	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;
    	}
    
    	err = got_opentemp_named(&new_fileindex_path, &findex, fileindex_path);
    	if (err)
    		goto done;
    
    	err = got_ref_resolve(&commit_id, repo, head_ref);
    	if (err)
    		goto done;
    
    	err = got_object_open(&obj, repo, commit_id);
    	if (err)
    		goto done;
    
    	if (got_object_get_type(obj) != GOT_OBJ_TYPE_COMMIT) {
    		err = got_error(GOT_ERR_OBJ_TYPE);
    		goto done;
    	}
    
    	err = got_object_commit_open(&commit, repo, obj);
    	if (err)
    		goto done;
    
    	got_object_close(obj);
    	err = got_object_open(&obj, repo, commit->tree_id);
    	if (err)
    		goto done;
    
    	if (got_object_get_type(obj) != GOT_OBJ_TYPE_TREE) {
    		err = got_error(GOT_ERR_OBJ_TYPE);
    		goto done;
    	}
    
    	err = got_object_tree_open(&tree, repo, obj);
    	if (err)
    		goto done;
    
    	err = tree_checkout(worktree, fileindex, tree, "/", repo,
    	    progress_cb, progress_arg, cancel_cb, cancel_arg);
    	if (err)
    		goto done;
    
    	err = got_fileindex_write(fileindex, findex);
    	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 (obj)
    		got_object_close(obj);
    	free(commit_id);
    	if (new_fileindex_path)
    		unlink(new_fileindex_path);
    	if (findex)
    		fclose(findex);
    	free(new_fileindex_path);
    	free(fileindex_path);
    	got_fileindex_close(fileindex);
    	unlockerr = lock_worktree(worktree, LOCK_SH);
    	if (unlockerr && err == NULL)
    		err = unlockerr;
    	return err;
    }