// Copyright 2010-2012 RethinkDB, all rights reserved.

#include "buffer_cache/mirrored/free_list.hpp"

#include "perfmon/perfmon.hpp"

#include "serializer/serializer.hpp"

#include "buffer_cache/mirrored/mirrored.hpp"

array_free_list_t::array_free_list_t(serializer_t *_serializer, mc_cache_stats_t *_stats)

: stats(_stats), serializer(_serializer)

{

on_thread_t switcher(serializer->home_thread());

num_blocks_in_use = 0;

next_new_block_id = serializer->max_block_id();

for (block_id_t i = 0; i < next_new_block_id; i++) {

if (serializer->get_delete_bit(i)) {

free_ids.push_back(i);

} else {

++stats->pm_n_blocks_total;

++num_blocks_in_use;

}

}

}

array_free_list_t::~array_free_list_t() {

}

void array_free_list_t::reserve_block_id(block_id_t id) {

if (id >= next_new_block_id) {

for (block_id_t i = next_new_block_id; i < id; i++) {

free_ids.push_back(i);

}

next_new_block_id = id + 1;

num_blocks_in_use++;

} else {

for (std::deque<block_id_t>::iterator it = free_ids.begin(); it != free_ids.end(); ++it) {

if (*it == id) {

free_ids.erase(it);

num_blocks_in_use++;

return;

}

}

unreachable("Tried to reserve a block id which is already taken.");

}

}

block_id_t array_free_list_t::gen_block_id() {

block_id_t id;

if (free_ids.empty()) {

id = next_new_block_id++;

} else {

id = free_ids.back();

free_ids.pop_back();

}

++stats->pm_n_blocks_total;

++num_blocks_in_use;

return id;

}

void array_free_list_t::release_block_id(block_id_t id) {

free_ids.push_back(id);

--stats->pm_n_blocks_total;

--num_blocks_in_use;

}