/**
 * 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 "call-stack.h"

#include <stdlib.h>



/**
 * An entry in the call-stack
 */
typedef struct mds_kbdc_call {
	/**
	 * The tree node where the call was made
	 */
	const mds_kbdc_tree_t *tree;

	/**
	 * The position of the line of the tree node
	 * where the call begins
	 */
	size_t start;

	/**
	 * The position of the line of the tree node
	 * where the call end
	 */
	size_t end;

	/**
	 * A snapshot of the include-stack as it
	 * looked when the call was being made
	 */
	mds_kbdc_include_stack_t *include_stack;
} mds_kbdc_call_t;



/**
 * 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 function- and macro-calls
 */
static mds_kbdc_call_t *restrict calls = NULL;

/**
 * The number elements allocated for `calls`
 */
static size_t calls_size = 0;

/**
 * The number elements stored in `calls`
 */
static size_t calls_ptr = 0;



/**
 * Add “called from here”-notes
 * 
 * @return  Zero on success, -1 on error
 */
int
mds_kbdc_call_stack_dump(void)
{
	char *old_pathname = result->pathname;
	mds_kbdc_source_code_t *old_source_code = result->source_code;
	size_t ptr = calls_ptr, iptr;
	mds_kbdc_call_t *restrict call;
	mds_kbdc_include_stack_t *restrict includes;

	while (ptr--) {
		call = calls + ptr;
		includes = call->include_stack;
		iptr = includes->ptr;
		result->pathname    = iptr ? includes->stack[iptr - 1]->filename    : original_pathname;
		result->source_code = iptr ? includes->stack[iptr - 1]->source_code : original_source_code;
		NEW_ERROR_(result, NOTE, 1, call->tree->loc_line, call->start, call->end, 1, "called from here");
		DUMP_INCLUDE_STACK(iptr);
	}

	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;
}


/**
 * Prepare for usage of call-stacks
 * 
 * @param  result_  The `result` parameter of root procedure that requires the call-stack
 */
void
mds_kbdc_call_stack_begin(mds_kbdc_parsed_t *restrict result_)
{
	result = result_;
	original_pathname = result_->pathname;
	original_source_code = result_->source_code;
}


/**
 * Cleanup after usage of call-stacks
 */
void
mds_kbdc_call_stack_end(void)
{
	result->pathname = original_pathname;
	result->source_code = original_source_code;
	free(calls), calls = NULL;
	calls_size = calls_ptr = 0;
}


/**
 * Mark an function- or macro-call
 * 
 * @param   tree   The tree node where the call was made
 * @param   start  The position of the line of the tree node where the call begins
 * @param   end    The position of the line of the tree node where the call end
 * @return         Zero on success, -1 on error
 */
int
mds_kbdc_call_stack_push(const mds_kbdc_tree_t *restrict tree, size_t start, size_t end)
{
	mds_kbdc_call_t *tmp;
	mds_kbdc_call_t *call;

	if (calls_ptr == calls_size) {
		fail_if (yrealloc(tmp, calls, calls_size + 4, mds_kbdc_call_t));
		calls_size += 4;
	}

	call = calls + calls_ptr++;
	call->tree = tree;
	call->start = start;
	call->end = end;
	call->include_stack = mds_kbdc_include_stack_save();
	fail_if (!call->include_stack);

	return 0;
fail:
	return -1;
}


/**
 * Undo the lasted not-undone call to `mds_kbdc_call_stack_push`
 * 
 * This function is guaranteed not to modify `errno`
 */
void
mds_kbdc_call_stack_pop(void)
{
	int saved_errno = errno;
	mds_kbdc_include_stack_free(calls[--calls_ptr].include_stack);
	errno = saved_errno;
}