parser-helper: Add utility class for flex/bison based parsers

src/libstrongswan/utils/parser_helper.c

@@ -0,0 +1,230 @@
+/*
+ * Copyright (C) 2014 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include <limits.h>
+#include <ctype.h>
+
+#include "parser_helper.h"
+
+#include <collections/array.h>
+
+typedef struct private_parser_helper_t private_parser_helper_t;
+typedef struct private_parser_helper_file_t private_parser_helper_file_t;
+
+struct private_parser_helper_t {
+
+	/**
+	 * Public interface.
+	 */
+	parser_helper_t public;
+
+	/**
+	 * Stack of included files, as private_parser_helper_file_t.
+	 */
+	array_t *files;
+
+	/**
+	 * Helper for parsing strings.
+	 */
+	bio_writer_t *writer;
+};
+
+struct private_parser_helper_file_t {
+
+	/**
+	 * File data.
+	 */
+	parser_helper_file_t public;
+
+	/**
+	 * Enumerator of paths matching the most recent inclusion pattern.
+	 */
+	enumerator_t *matches;
+};
+
+/**
+ * Destroy the given file data.
+ */
+static void parser_helper_file_destroy(private_parser_helper_file_t *this)
+{
+	if (this->public.file)
+	{
+		fclose(this->public.file);
+	}
+	free(this->public.name);
+	DESTROY_IF(this->matches);
+	free(this);
+}
+
+METHOD(parser_helper_t, file_current, parser_helper_file_t*,
+	private_parser_helper_t *this)
+{
+	private_parser_helper_file_t *file;
+
+	array_get(this->files, ARRAY_TAIL, &file);
+	if (file->public.name)
+	{
+		return &file->public;
+	}
+	return NULL;
+}
+
+METHOD(parser_helper_t, file_next, parser_helper_file_t*,
+	private_parser_helper_t *this)
+{
+	private_parser_helper_file_t *file, *next;
+	char *name;
+
+	array_get(this->files, ARRAY_TAIL, &file);
+	if (!file->matches)
+	{
+		array_remove(this->files, ARRAY_TAIL, NULL);
+		parser_helper_file_destroy(file);
+		/* continue with previous includes, if any */
+		array_get(this->files, ARRAY_TAIL, &file);
+	}
+	if (file->matches)
+	{
+		while (file->matches->enumerate(file->matches, &name, NULL))
+		{
+			INIT(next,
+				.public = {
+					.name = strdup(name),
+					.file = fopen(name, "r"),
+				},
+			);
+
+			if (next->public.file)
+			{
+				array_insert(this->files, ARRAY_TAIL, next);
+				return &next->public;
+			}
+			PARSER_DBG1(&this->public, "unable to open '%s'", name);
+			parser_helper_file_destroy(next);
+		}
+		file->matches->destroy(file->matches);
+		file->matches = NULL;
+	}
+	return NULL;
+}
+
+METHOD(parser_helper_t, file_include, void,
+	private_parser_helper_t *this, char *pattern)
+{
+	private_parser_helper_file_t *file;
+	char pat[PATH_MAX];
+
+	array_get(this->files, ARRAY_TAIL, &file);
+	if (!pattern || !*pattern)
+	{
+		PARSER_DBG1(&this->public, "no include pattern specified, ignored");
+		file->matches = enumerator_create_empty();
+		return;
+	}
+
+	if (!file->public.name || pattern[0] == '/')
+	{	/* absolute path */
+		if (snprintf(pat, sizeof(pat), "%s", pattern) >= sizeof(pat))
+		{
+			PARSER_DBG1(&this->public, "include pattern too long, ignored");
+			file->matches = enumerator_create_empty();
+			return;
+		}
+	}
+	else
+	{	/* base relative paths to the directory of the current file */
+		char *dir = path_dirname(file->public.name);
+		if (snprintf(pat, sizeof(pat), "%s/%s", dir, pattern) >= sizeof(pat))
+		{
+			PARSER_DBG1(&this->public, "include pattern too long, ignored");
+			free(dir);
+			file->matches = enumerator_create_empty();
+			return;
+		}
+		free(dir);
+	}
+
+	file->matches = enumerator_create_glob(pat);
+	if (!file->matches)
+	{	/* if glob(3) is not available, try to load pattern directly */
+		file->matches = enumerator_create_single(strdup(pat), free);
+	}
+}
+
+METHOD(parser_helper_t, string_init, void,
+	private_parser_helper_t *this)
+{
+	chunk_t data;
+
+	data = this->writer->extract_buf(this->writer);
+	chunk_free(&data);
+}
+
+METHOD(parser_helper_t, string_add, void,
+	private_parser_helper_t *this, char *str)
+{
+	this->writer->write_data(this->writer, chunk_from_str(str));
+}
+
+METHOD(parser_helper_t, string_get, char*,
+	private_parser_helper_t *this)
+{
+	chunk_t data;
+
+	this->writer->write_data(this->writer, chunk_from_chars('\0'));
+	data = this->writer->extract_buf(this->writer);
+	return data.ptr;
+}
+
+METHOD(parser_helper_t, destroy, void,
+	private_parser_helper_t *this)
+{
+	array_destroy_function(this->files, (void*)parser_helper_file_destroy, NULL);
+	this->writer->destroy(this->writer);
+	free(this);
+}
+
+/**
+ * Described in header
+ */
+parser_helper_t *parser_helper_create(void *context)
+{
+	private_parser_helper_t *this;
+	private_parser_helper_file_t *sentinel;
+
+	INIT(this,
+		.public = {
+			.context = context,
+			.file_current = _file_current,
+			.file_include = _file_include,
+			.file_next = _file_next,
+			.string_init = _string_init,
+			.string_add = _string_add,
+			.string_get = _string_get,
+			.destroy = _destroy,
+		},
+		.files = array_create(0, 0),
+		.writer = bio_writer_create(0),
+	);
+
+	INIT(sentinel,
+		.public = {
+			.name = NULL,
+		},
+	);
+	array_insert(this->files, ARRAY_TAIL, sentinel);
+
+	return &this->public;
+}