path: root/src/mds-kbdc/include-stack.c

/**
 * mds — A micro-display server
 * Copyright © 2014, 2015, 2016, 2017  Mattias Andrée (m@maandree.se)
 * 
 * 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 3 of the License, or
 * (at your option) any later version.
 * 
 * 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.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "include-stack.h"

#include <alloca.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>



/**
 * Variable whether the latest created error is stored
 */
static mds_kbdc_parse_error_t *error;

/**
 * The `result` parameter of root procedure that requires the include-stack
 */
static mds_kbdc_parsed_t *result;

/**
 * The original value of `result->pathname`
 */
static char *original_pathname;

/**
 * The original value of `result->source_code`
 */
static mds_kbdc_source_code_t *original_source_code;

/**
 * Stack of visited include-statements
 */
static const mds_kbdc_tree_include_t **restrict includes = NULL;

/**
 * The number elements allocated for `includes`
 */
static size_t includes_size = 0;

/**
 * The number elements stored in `includes`
 */
size_t includes_ptr = 0;

/**
 * The latest saved include-stack
 */
static mds_kbdc_include_stack_t *latest_save = NULL;



/**
 * Add “included from here”-notes
 * 
 * @param   ptr  The number of “included from here”-notes
 * @return       Zero on success, -1 on error
 */
int
mds_kbdc_include_stack_dump(size_t ptr)
{
	char *old_pathname = result->pathname;
	mds_kbdc_source_code_t *old_source_code = result->source_code;
	while (ptr--) {
		result->pathname    = ptr ? includes[ptr - 1]->filename    : original_pathname;
		result->source_code = ptr ? includes[ptr - 1]->source_code : original_source_code;
		NEW_ERROR_WITHOUT_INCLUDES(includes[ptr], NOTE, "included from here");
	}
	result->pathname = old_pathname;
	result->source_code = old_source_code;
	return 0;
fail:
	result->pathname = old_pathname;
	result->source_code = old_source_code;
	return -1;
} 


/**
 * Mark the root of the tree as included
 * 
 * @param  result_  The `result` parameter of root procedure that requires the include-stack
 */
void
mds_kbdc_include_stack_begin(mds_kbdc_parsed_t *restrict result_)
{
	result = result_;
	original_pathname = result_->pathname;
	original_source_code = result_->source_code;
}


/**
 * Mark the root of the tree as no longer being visited,
 * and release clean up after the use of this module
 */
void
mds_kbdc_include_stack_end(void)
{
	latest_save = NULL;
	result->pathname = original_pathname;
	result->source_code = original_source_code;
	free(includes), includes = NULL;
	includes_size = includes_ptr = 0;
}


/**
 * Mark an include-statement as visited
 * 
 * @param   tree  The visisted include-statement
 * @param   data  Output parameter with stack information that should be passed to
 *                the corresponding call to `mds_kbdc_include_stack_pop`, `*data`
 *                is undefined on error
 * @return        Zero on success, -1 on error
 */
int
mds_kbdc_include_stack_push(const mds_kbdc_tree_include_t *restrict tree, void **data)
{
	const mds_kbdc_tree_include_t **old = NULL;
	int saved_errno;

	if (includes_ptr == includes_size)
		fail_if (xxrealloc(old, includes, includes_size += 4, const mds_kbdc_tree_include_t*));

	fail_if (xmalloc(*data, 3, void*));

	((char **)(*data))[0] = result->pathname;
	((mds_kbdc_source_code_t **)(*data))[1] = result->source_code;
	((mds_kbdc_include_stack_t **)(*data))[2] = latest_save;

	includes[includes_ptr++] = tree;
	result->pathname = tree->filename;
	result->source_code = tree->source_code;
	latest_save = NULL;

	return 0;
fail:
	saved_errno = errno;
	free(old);
	return errno = saved_errno, -1;
}


/**
 * Undo the lasted not-undone call to `mds_kbdc_include_stack_push`
 * 
 * This function is guaranteed not to modify `errno`
 * 
 * @param  data  `*data` from `mds_kbdc_include_stack_push`
 */
void
mds_kbdc_include_stack_pop(void *data)
{
	int saved_errno = errno;
	result->pathname = ((char **)data)[0];
	result->source_code = ((mds_kbdc_source_code_t **)data)[1];
	latest_save = ((mds_kbdc_include_stack_t **)data)[2];
	includes_ptr--;
	free(data);
	errno = saved_errno;
}


/**
 * Save the current include-stack
 * 
 * @return  The include-stack, `NULL` on error
 */
mds_kbdc_include_stack_t *
mds_kbdc_include_stack_save(void)
{
	int saved_errno;

	if (latest_save) {
		latest_save->duplicates++;
		return latest_save;
	}

	fail_if (xmalloc(latest_save, 1, mds_kbdc_include_stack_t));

	latest_save->stack = NULL;
	latest_save->ptr = includes_ptr;
	latest_save->duplicates = 0;

	if (!latest_save->ptr)
		return latest_save;

	fail_if (xmemdup(latest_save->stack, includes, latest_save->ptr, const mds_kbdc_tree_include_t*));

	return latest_save;
fail:
	saved_errno = errno;
	if (latest_save)
		free(latest_save->stack), latest_save = NULL;
	errno = saved_errno;
	return NULL;
}


/**
 * Restore a previous include-stack
 * 
 * @param   stack  The include-stack
 * @return         Zero on success, -1 on error
 */
int
mds_kbdc_include_stack_restore(mds_kbdc_include_stack_t *restrict stack)
{
	const mds_kbdc_tree_include_t **tmp;

	latest_save = stack;

	if (stack->ptr > includes_size) {
		fail_if (yrealloc(tmp, includes, stack->ptr, const mds_kbdc_tree_include_t *));
		includes_size = stack->ptr;
	}

	memcpy(includes, stack->stack, stack->ptr * sizeof(const mds_kbdc_tree_include_t *));
	includes_ptr = stack->ptr;
	return 0;
fail:
	return -1;
}


/**
 * Destroy a previous include-stack and free its allocation
 * 
 * @param  stack  The include-stack
 */
void
mds_kbdc_include_stack_free(mds_kbdc_include_stack_t *restrict stack)
{
	if (!stack || stack->duplicates--)
		return;
	free(stack->stack);
	free(stack);
	if (latest_save == stack)
		latest_save = NULL;
}