thodg/libgit2/src/ignore.c

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• Hash : a7b4b639
  Author :
  Date : 2019-08-24T12:14:31
  

  ignore: correct handling of nested rules overriding wild card unignore problem: filesystem_iterator loads .gitignore files in top-down order. subsequently, ignore module evaluates them in the order they are loaded. this creates a problem if we have unignored a rule (using a wild card) in a sub dir and ignored it again in a level further below (see the test included in this patch). solution: process ignores in reverse order. closes #4963

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• src/ignore.c

• /*
   * 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 "ignore.h"
  
  #include "git2/ignore.h"
  #include "common.h"
  #include "attrcache.h"
  #include "path.h"
  #include "config.h"
  #include "wildmatch.h"
  
  #define GIT_IGNORE_INTERNAL		"[internal]exclude"
  
  #define GIT_IGNORE_DEFAULT_RULES ".\n..\n.git\n"
  
  /**
   * A negative ignore pattern can negate a positive one without
   * wildcards if it is a basename only and equals the basename of
   * the positive pattern. Thus
   *
   * foo/bar
   * !bar
   *
   * would result in foo/bar being unignored again while
   *
   * moo/foo/bar
   * !foo/bar
   *
   * would do nothing. The reverse also holds true: a positive
   * basename pattern can be negated by unignoring the basename in
   * subdirectories. Thus
   *
   * bar
   * !foo/bar
   *
   * would result in foo/bar being unignored again. As with the
   * first case,
   *
   * foo/bar
   * !moo/foo/bar
   *
   * would do nothing, again.
   */
  static int does_negate_pattern(git_attr_fnmatch *rule, git_attr_fnmatch *neg)
  {
  	int (*cmp)(const char *, const char *, size_t);
  	git_attr_fnmatch *longer, *shorter;
  	char *p;
  
  	if ((rule->flags & GIT_ATTR_FNMATCH_NEGATIVE) != 0
  	    || (neg->flags & GIT_ATTR_FNMATCH_NEGATIVE) == 0)
  		return false;
  
  	if (neg->flags & GIT_ATTR_FNMATCH_ICASE)
  		cmp = git__strncasecmp;
  	else
  		cmp = git__strncmp;
  
  	/* If lengths match we need to have an exact match */
  	if (rule->length == neg->length) {
  		return cmp(rule->pattern, neg->pattern, rule->length) == 0;
  	} else if (rule->length < neg->length) {
  		shorter = rule;
  		longer = neg;
  	} else {
  		shorter = neg;
  		longer = rule;
  	}
  
  	/* Otherwise, we need to check if the shorter
  	 * rule is a basename only (that is, it contains
  	 * no path separator) and, if so, if it
  	 * matches the tail of the longer rule */
  	p = longer->pattern + longer->length - shorter->length;
  
  	if (p[-1] != '/')
  		return false;
  	if (memchr(shorter->pattern, '/', shorter->length) != NULL)
  		return false;
  
  	return cmp(p, shorter->pattern, shorter->length) == 0;
  }
  
  /**
   * A negative ignore can only unignore a file which is given explicitly before, thus
   *
   *    foo
   *    !foo/bar
   *
   * does not unignore 'foo/bar' as it's not in the list. However
   *
   *    foo/<star>
   *    !foo/bar
   *
   * does unignore 'foo/bar', as it is contained within the 'foo/<star>' rule.
   */
  static int does_negate_rule(int *out, git_vector *rules, git_attr_fnmatch *match)
  {
  	int error = 0, wildmatch_flags;
  	size_t i;
  	git_attr_fnmatch *rule;
  	char *path;
  	git_buf buf = GIT_BUF_INIT;
  
  	*out = 0;
  
  	wildmatch_flags = WM_PATHNAME;
  	if (match->flags & GIT_ATTR_FNMATCH_ICASE)
  		wildmatch_flags |= WM_CASEFOLD;
  
  	/* path of the file relative to the workdir, so we match the rules in subdirs */
  	if (match->containing_dir) {
  		git_buf_puts(&buf, match->containing_dir);
  	}
  	if (git_buf_puts(&buf, match->pattern) < 0)
  		return -1;
  
  	path = git_buf_detach(&buf);
  
  	git_vector_foreach(rules, i, rule) {
  		if (!(rule->flags & GIT_ATTR_FNMATCH_HASWILD)) {
  			if (does_negate_pattern(rule, match)) {
  				error = 0;
  				*out = 1;
  				goto out;
  			}
  			else
  				continue;
  		}
  
  		git_buf_clear(&buf);
  		if (rule->containing_dir)
  			git_buf_puts(&buf, rule->containing_dir);
  		git_buf_puts(&buf, rule->pattern);
  
  		if (git_buf_oom(&buf))
  			goto out;
  
  		/* if we found a match, we want to keep this rule */
  		if ((wildmatch(git_buf_cstr(&buf), path, wildmatch_flags)) == WM_MATCH) {
  			*out = 1;
  			error = 0;
  			goto out;
  		}
  	}
  
  	error = 0;
  
  out:
  	git__free(path);
  	git_buf_dispose(&buf);
  	return error;
  }
  
  static int parse_ignore_file(
  	git_repository *repo, git_attr_file *attrs, const char *data, bool allow_macros)
  {
  	int error = 0;
  	int ignore_case = false;
  	const char *scan = data, *context = NULL;
  	git_attr_fnmatch *match = NULL;
  
  	GIT_UNUSED(allow_macros);
  
  	if (git_repository__configmap_lookup(&ignore_case, repo, GIT_CONFIGMAP_IGNORECASE) < 0)
  		git_error_clear();
  
  	/* if subdir file path, convert context for file paths */
  	if (attrs->entry &&
  		git_path_root(attrs->entry->path) < 0 &&
  		!git__suffixcmp(attrs->entry->path, "/" GIT_IGNORE_FILE))
  		context = attrs->entry->path;
  
  	if (git_mutex_lock(&attrs->lock) < 0) {
  		git_error_set(GIT_ERROR_OS, "failed to lock ignore file");
  		return -1;
  	}
  
  	while (!error && *scan) {
  		int valid_rule = 1;
  
  		if (!match && !(match = git__calloc(1, sizeof(*match)))) {
  			error = -1;
  			break;
  		}
  
  		match->flags =
  		    GIT_ATTR_FNMATCH_ALLOWSPACE | GIT_ATTR_FNMATCH_ALLOWNEG;
  
  		if (!(error = git_attr_fnmatch__parse(
  			match, &attrs->pool, context, &scan)))
  		{
  			match->flags |= GIT_ATTR_FNMATCH_IGNORE;
  
  			if (ignore_case)
  				match->flags |= GIT_ATTR_FNMATCH_ICASE;
  
  			scan = git__next_line(scan);
  
  			/*
  			 * If a negative match doesn't actually do anything,
  			 * throw it away. As we cannot always verify whether a
  			 * rule containing wildcards negates another rule, we
  			 * do not optimize away these rules, though.
  			 * */
  			if (match->flags & GIT_ATTR_FNMATCH_NEGATIVE
  			    && !(match->flags & GIT_ATTR_FNMATCH_HASWILD))
  				error = does_negate_rule(&valid_rule, &attrs->rules, match);
  
  			if (!error && valid_rule)
  				error = git_vector_insert(&attrs->rules, match);
  		}
  
  		if (error != 0 || !valid_rule) {
  			match->pattern = NULL;
  
  			if (error == GIT_ENOTFOUND)
  				error = 0;
  		} else {
  			match = NULL; /* vector now "owns" the match */
  		}
  	}
  
  	git_mutex_unlock(&attrs->lock);
  	git__free(match);
  
  	return error;
  }
  
  static int push_ignore_file(
  	git_ignores *ignores,
  	git_vector *which_list,
  	const char *base,
  	const char *filename)
  {
  	int error = 0;
  	git_attr_file *file = NULL;
  
  	error = git_attr_cache__get(&file, ignores->repo, NULL, GIT_ATTR_FILE__FROM_FILE,
  				    base, filename, parse_ignore_file, false);
  	if (error < 0)
  		return error;
  
  	if (file != NULL) {
  		if ((error = git_vector_insert(which_list, file)) < 0)
  			git_attr_file__free(file);
  	}
  
  	return error;
  }
  
  static int push_one_ignore(void *payload, const char *path)
  {
  	git_ignores *ign = payload;
  	ign->depth++;
  	return push_ignore_file(ign, &ign->ign_path, path, GIT_IGNORE_FILE);
  }
  
  static int get_internal_ignores(git_attr_file **out, git_repository *repo)
  {
  	int error;
  
  	if ((error = git_attr_cache__init(repo)) < 0)
  		return error;
  
  	error = git_attr_cache__get(out, repo, NULL, GIT_ATTR_FILE__IN_MEMORY, NULL,
  				    GIT_IGNORE_INTERNAL, NULL, false);
  
  	/* if internal rules list is empty, insert default rules */
  	if (!error && !(*out)->rules.length)
  		error = parse_ignore_file(repo, *out, GIT_IGNORE_DEFAULT_RULES, false);
  
  	return error;
  }
  
  int git_ignore__for_path(
  	git_repository *repo,
  	const char *path,
  	git_ignores *ignores)
  {
  	int error = 0;
  	const char *workdir = git_repository_workdir(repo);
  	git_buf infopath = GIT_BUF_INIT;
  
  	assert(repo && ignores && path);
  
  	memset(ignores, 0, sizeof(*ignores));
  	ignores->repo = repo;
  
  	/* Read the ignore_case flag */
  	if ((error = git_repository__configmap_lookup(
  			&ignores->ignore_case, repo, GIT_CONFIGMAP_IGNORECASE)) < 0)
  		goto cleanup;
  
  	if ((error = git_attr_cache__init(repo)) < 0)
  		goto cleanup;
  
  	/* given a unrooted path in a non-bare repo, resolve it */
  	if (workdir && git_path_root(path) < 0) {
  		git_buf local = GIT_BUF_INIT;
  
  		if ((error = git_path_dirname_r(&local, path)) < 0 ||
  		    (error = git_path_resolve_relative(&local, 0)) < 0 ||
  		    (error = git_path_to_dir(&local)) < 0 ||
  		    (error = git_buf_joinpath(&ignores->dir, workdir, local.ptr)) < 0)
  		{;} /* Nothing, we just want to stop on the first error */
  		git_buf_dispose(&local);
  	} else {
  		error = git_buf_joinpath(&ignores->dir, path, "");
  	}
  	if (error < 0)
  		goto cleanup;
  
  	if (workdir && !git__prefixcmp(ignores->dir.ptr, workdir))
  		ignores->dir_root = strlen(workdir);
  
  	/* set up internals */
  	if ((error = get_internal_ignores(&ignores->ign_internal, repo)) < 0)
  		goto cleanup;
  
  	/* load .gitignore up the path */
  	if (workdir != NULL) {
  		error = git_path_walk_up(
  			&ignores->dir, workdir, push_one_ignore, ignores);
  		if (error < 0)
  			goto cleanup;
  	}
  
  	/* load .git/info/exclude if possible */
  	if ((error = git_repository_item_path(&infopath, repo, GIT_REPOSITORY_ITEM_INFO)) < 0 ||
  		(error = push_ignore_file(ignores, &ignores->ign_global, infopath.ptr, GIT_IGNORE_FILE_INREPO)) < 0) {
  		if (error != GIT_ENOTFOUND)
  			goto cleanup;
  		error = 0;
  	}
  
  	/* load core.excludesfile */
  	if (git_repository_attr_cache(repo)->cfg_excl_file != NULL)
  		error = push_ignore_file(
  			ignores, &ignores->ign_global, NULL,
  			git_repository_attr_cache(repo)->cfg_excl_file);
  
  cleanup:
  	git_buf_dispose(&infopath);
  	if (error < 0)
  		git_ignore__free(ignores);
  
  	return error;
  }
  
  int git_ignore__push_dir(git_ignores *ign, const char *dir)
  {
  	if (git_buf_joinpath(&ign->dir, ign->dir.ptr, dir) < 0)
  		return -1;
  
  	ign->depth++;
  
  	return push_ignore_file(
  		ign, &ign->ign_path, ign->dir.ptr, GIT_IGNORE_FILE);
  }
  
  int git_ignore__pop_dir(git_ignores *ign)
  {
  	if (ign->ign_path.length > 0) {
  		git_attr_file *file = git_vector_last(&ign->ign_path);
  		const char *start = file->entry->path, *end;
  
  		/* - ign->dir looks something like "/home/user/a/b/" (or "a/b/c/d/")
  		 * - file->path looks something like "a/b/.gitignore
  		 *
  		 * We are popping the last directory off ign->dir.  We also want
  		 * to remove the file from the vector if the popped directory
  		 * matches the ignore path.  We need to test if the "a/b" part of
  		 * the file key matches the path we are about to pop.
  		 */
  
  		if ((end = strrchr(start, '/')) != NULL) {
  			size_t dirlen = (end - start) + 1;
  			const char *relpath = ign->dir.ptr + ign->dir_root;
  			size_t pathlen = ign->dir.size - ign->dir_root;
  
  			if (pathlen == dirlen && !memcmp(relpath, start, dirlen)) {
  				git_vector_pop(&ign->ign_path);
  				git_attr_file__free(file);
  			}
  		}
  	}
  
  	if (--ign->depth > 0) {
  		git_buf_rtruncate_at_char(&ign->dir, '/');
  		git_path_to_dir(&ign->dir);
  	}
  
  	return 0;
  }
  
  void git_ignore__free(git_ignores *ignores)
  {
  	unsigned int i;
  	git_attr_file *file;
  
  	git_attr_file__free(ignores->ign_internal);
  
  	git_vector_foreach(&ignores->ign_path, i, file) {
  		git_attr_file__free(file);
  		ignores->ign_path.contents[i] = NULL;
  	}
  	git_vector_free(&ignores->ign_path);
  
  	git_vector_foreach(&ignores->ign_global, i, file) {
  		git_attr_file__free(file);
  		ignores->ign_global.contents[i] = NULL;
  	}
  	git_vector_free(&ignores->ign_global);
  
  	git_buf_dispose(&ignores->dir);
  }
  
  static bool ignore_lookup_in_rules(
  	int *ignored, git_attr_file *file, git_attr_path *path)
  {
  	size_t j;
  	git_attr_fnmatch *match;
  
  	git_vector_rforeach(&file->rules, j, match) {
  		if (match->flags & GIT_ATTR_FNMATCH_DIRECTORY &&
  		    path->is_dir == GIT_DIR_FLAG_FALSE)
  			continue;
  		if (git_attr_fnmatch__match(match, path)) {
  			*ignored = ((match->flags & GIT_ATTR_FNMATCH_NEGATIVE) == 0) ?
  				GIT_IGNORE_TRUE : GIT_IGNORE_FALSE;
  			return true;
  		}
  	}
  
  	return false;
  }
  
  int git_ignore__lookup(
  	int *out, git_ignores *ignores, const char *pathname, git_dir_flag dir_flag)
  {
  	size_t i;
  	git_attr_file *file;
  	git_attr_path path;
  
  	*out = GIT_IGNORE_NOTFOUND;
  
  	if (git_attr_path__init(
  		&path, pathname, git_repository_workdir(ignores->repo), dir_flag) < 0)
  		return -1;
  
  	/* first process builtins - success means path was found */
  	if (ignore_lookup_in_rules(out, ignores->ign_internal, &path))
  		goto cleanup;
  
  	/* next process files in the path.
  	 * this process has to process ignores in reverse order
  	 * to ensure correct prioritization of rules
  	 */
  	git_vector_rforeach(&ignores->ign_path, i, file) {
  		if (ignore_lookup_in_rules(out, file, &path))
  			goto cleanup;
  	}
  
  	/* last process global ignores */
  	git_vector_foreach(&ignores->ign_global, i, file) {
  		if (ignore_lookup_in_rules(out, file, &path))
  			goto cleanup;
  	}
  
  cleanup:
  	git_attr_path__free(&path);
  	return 0;
  }
  
  int git_ignore_add_rule(git_repository *repo, const char *rules)
  {
  	int error;
  	git_attr_file *ign_internal = NULL;
  
  	if ((error = get_internal_ignores(&ign_internal, repo)) < 0)
  		return error;
  
  	error = parse_ignore_file(repo, ign_internal, rules, false);
  	git_attr_file__free(ign_internal);
  
  	return error;
  }
  
  int git_ignore_clear_internal_rules(git_repository *repo)
  {
  	int error;
  	git_attr_file *ign_internal;
  
  	if ((error = get_internal_ignores(&ign_internal, repo)) < 0)
  		return error;
  
  	if (!(error = git_attr_file__clear_rules(ign_internal, true)))
  		error = parse_ignore_file(
  				repo, ign_internal, GIT_IGNORE_DEFAULT_RULES, false);
  
  	git_attr_file__free(ign_internal);
  	return error;
  }
  
  int git_ignore_path_is_ignored(
  	int *ignored,
  	git_repository *repo,
  	const char *pathname)
  {
  	int error;
  	const char *workdir;
  	git_attr_path path;
  	git_ignores ignores;
  	unsigned int i;
  	git_attr_file *file;
  	git_dir_flag dir_flag = GIT_DIR_FLAG_UNKNOWN;
  
  	assert(repo && ignored && pathname);
  
  	workdir = git_repository_workdir(repo);
  
  	memset(&path, 0, sizeof(path));
  	memset(&ignores, 0, sizeof(ignores));
  
  	if (!git__suffixcmp(pathname, "/"))
  		dir_flag = GIT_DIR_FLAG_TRUE;
  	else if (git_repository_is_bare(repo))
  		dir_flag = GIT_DIR_FLAG_FALSE;
  
  	if ((error = git_attr_path__init(&path, pathname, workdir, dir_flag)) < 0 ||
  		(error = git_ignore__for_path(repo, path.path, &ignores)) < 0)
  		goto cleanup;
  
  	while (1) {
  		/* first process builtins - success means path was found */
  		if (ignore_lookup_in_rules(ignored, ignores.ign_internal, &path))
  			goto cleanup;
  
  		/* next process files in the path */
  		git_vector_foreach(&ignores.ign_path, i, file) {
  			if (ignore_lookup_in_rules(ignored, file, &path))
  				goto cleanup;
  		}
  
  		/* last process global ignores */
  		git_vector_foreach(&ignores.ign_global, i, file) {
  			if (ignore_lookup_in_rules(ignored, file, &path))
  				goto cleanup;
  		}
  
  		/* move up one directory */
  		if (path.basename == path.path)
  			break;
  		path.basename[-1] = '\0';
  		while (path.basename > path.path && *path.basename != '/')
  			path.basename--;
  		if (path.basename > path.path)
  			path.basename++;
  		path.is_dir = 1;
  
  		if ((error = git_ignore__pop_dir(&ignores)) < 0)
  			break;
  	}
  
  	*ignored = 0;
  
  cleanup:
  	git_attr_path__free(&path);
  	git_ignore__free(&ignores);
  	return error;
  }
  
  int git_ignore__check_pathspec_for_exact_ignores(
  	git_repository *repo,
  	git_vector *vspec,
  	bool no_fnmatch)
  {
  	int error = 0;
  	size_t i;
  	git_attr_fnmatch *match;
  	int ignored;
  	git_buf path = GIT_BUF_INIT;
  	const char *wd, *filename;
  	git_index *idx;
  
  	if ((error = git_repository__ensure_not_bare(
  			repo, "validate pathspec")) < 0 ||
  		(error = git_repository_index(&idx, repo)) < 0)
  		return error;
  
  	wd = git_repository_workdir(repo);
  
  	git_vector_foreach(vspec, i, match) {
  		/* skip wildcard matches (if they are being used) */
  		if ((match->flags & GIT_ATTR_FNMATCH_HASWILD) != 0 &&
  			!no_fnmatch)
  			continue;
  
  		filename = match->pattern;
  
  		/* if file is already in the index, it's fine */
  		if (git_index_get_bypath(idx, filename, 0) != NULL)
  			continue;
  
  		if ((error = git_buf_joinpath(&path, wd, filename)) < 0)
  			break;
  
  		/* is there a file on disk that matches this exactly? */
  		if (!git_path_isfile(path.ptr))
  			continue;
  
  		/* is that file ignored? */
  		if ((error = git_ignore_path_is_ignored(&ignored, repo, filename)) < 0)
  			break;
  
  		if (ignored) {
  			git_error_set(GIT_ERROR_INVALID, "pathspec contains ignored file '%s'",
  				filename);
  			error = GIT_EINVALIDSPEC;
  			break;
  		}
  	}
  
  	git_index_free(idx);
  	git_buf_dispose(&path);
  
  	return error;
  }
  
  

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