// Speculative tapset
// Copyright (C) 2011 Red Hat Inc.
//
// This file is part of systemtap, and is free software.  You can
// redistribute it and/or modify it under the terms of the GNU General
// Public License (GPL); either version 2, or (at your option) any
// later version.

global _spec_id
global _spec_counter
global _spec_buff
global _spec_discard

/**
 * sfunction speculation - Allocate a new id for speculative output
 *
 * The speculation() function is called when a new speculation buffer is needed.
 * It returns an id for the speculative output.
 * There can be multiple threads being speculated on concurrently.
 * This id is used by other speculation functions to keep the threads
 * separate.
 */
function speculation:long ()
{
	_spec_id += 1
	return _spec_id
}


/**
 * sfunction speculate - Store a string for possible output later
 * @id: buffer id to store the information in
 * @output: string to write out when commit occurs
 *
 * Add a string to the speculaive buffer for id.
 */
function speculate (id:long, output:string)
{
	_spec_counter[id] += 1
	_spec_buff[id, _spec_counter[id]] = output
}


function _spec_erase (id:long) {
	foreach([i, counter] in _spec_discard)
		delete _spec_buff[i, counter]
	delete _spec_discard
}


/**
 * sfunction discard - Discard all output related to a speculation buffer
 * @id: of the buffer to store the information in
 *
 */
function discard (id:long)
{
	foreach([i, counter] in _spec_buff)
		if (i==id) _spec_discard[i, counter] = 1
	_spec_erase (id)
}


/**
 * sfunction commit - Write out all output related to a speculation buffer
 * @id: of the buffer to store the information in
 *
 * Output all the output for @id in the order that it was entered into
 * the speculative buffer by speculative().
 */
function commit (id:long)
{
	foreach([i, counter+] in _spec_buff) {
		if (i==id) {
			printf("%s", _spec_buff[i, counter])
			_spec_discard[i, counter] = 1
		}
	}
	_spec_erase (id)
}