/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4:
/*======
This file is part of PerconaFT.


Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved.

    PerconaFT is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License, version 2,
    as published by the Free Software Foundation.

    PerconaFT 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 PerconaFT.  If not, see <http://www.gnu.org/licenses/>.

----------------------------------------

    PerconaFT is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License, version 3,
    as published by the Free Software Foundation.

    PerconaFT 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 Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with PerconaFT.  If not, see <http://www.gnu.org/licenses/>.
======= */

#ident "Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved."

#include <my_global.h>
#include <string>

#include "portability/memory.h"

#include "ft/node.h"
#include "ft/serialize/rbuf.h"
#include "ft/serialize/wbuf.h"

void ftnode_pivot_keys::create_empty() {
    _num_pivots = 0;
    _total_size = 0;
    _fixed_keys = nullptr;
    _fixed_keylen = 0;
    _fixed_keylen_aligned = 0;
    _dbt_keys = nullptr;
}

void ftnode_pivot_keys::create_from_dbts(const DBT *keys, int n) {
    create_empty();
    _num_pivots = n;

    // see if every key has the same length
    bool keys_same_size = true;
    for (int i = 1; i < _num_pivots; i++) {
        if (keys[i].size != keys[i - 1].size) {
            keys_same_size = false;
            break;
        }
    }

    if (keys_same_size && _num_pivots > 0) {
        // if so, store pivots in a tightly packed array of fixed length keys
        _fixed_keylen = keys[0].size;
        _fixed_keylen_aligned = _align4(_fixed_keylen);
        _total_size = _fixed_keylen_aligned * _num_pivots;
        XMALLOC_N_ALIGNED(64, _total_size, _fixed_keys);
        for (int i = 0; i < _num_pivots; i++) {
            invariant(keys[i].size == _fixed_keylen);
            memcpy(_fixed_key(i), keys[i].data, _fixed_keylen);
        }
    } else {
        // otherwise we'll just store the pivots in an array of dbts
        XMALLOC_N_ALIGNED(64, _num_pivots, _dbt_keys);
        for (int i = 0; i < _num_pivots; i++) {
            size_t size = keys[i].size;
            toku_memdup_dbt(&_dbt_keys[i], keys[i].data, size);
            _total_size += size;
        }
    }

    sanity_check();
}

void ftnode_pivot_keys::_create_from_fixed_keys(const char *fixedkeys, size_t fixed_keylen, int n) {
    create_empty();
    _num_pivots = n;
    _fixed_keylen = fixed_keylen;
    _fixed_keylen_aligned = _align4(fixed_keylen);
    _total_size = _fixed_keylen_aligned * _num_pivots;
    XMEMDUP_N(_fixed_keys, fixedkeys, _total_size);
}

// effect: create pivot keys as a clone of an existing set of pivotkeys
void ftnode_pivot_keys::create_from_pivot_keys(const ftnode_pivot_keys &pivotkeys) {
    if (pivotkeys._fixed_format()) {
        _create_from_fixed_keys(pivotkeys._fixed_keys, pivotkeys._fixed_keylen, pivotkeys._num_pivots);
    } else {
        create_from_dbts(pivotkeys._dbt_keys, pivotkeys._num_pivots);
    }

    sanity_check();
}

void ftnode_pivot_keys::destroy() {
    if (_dbt_keys != nullptr) {
        for (int i = 0; i < _num_pivots; i++) {
            toku_destroy_dbt(&_dbt_keys[i]);
        }
        toku_free(_dbt_keys);
        _dbt_keys = nullptr;
    }
    if (_fixed_keys != nullptr) {
        toku_free(_fixed_keys);
        _fixed_keys = nullptr;
    }
    _fixed_keylen = 0;
    _fixed_keylen_aligned = 0;
    _num_pivots = 0;
    _total_size = 0;
}

void ftnode_pivot_keys::_convert_to_fixed_format() {
    invariant(!_fixed_format());

    // convert to a tightly packed array of fixed length keys
    _fixed_keylen = _dbt_keys[0].size;
    _fixed_keylen_aligned = _align4(_fixed_keylen);
    _total_size = _fixed_keylen_aligned * _num_pivots;
    XMALLOC_N_ALIGNED(64, _total_size, _fixed_keys);
    for (int i = 0; i < _num_pivots; i++) {
        invariant(_dbt_keys[i].size == _fixed_keylen);
        memcpy(_fixed_key(i), _dbt_keys[i].data, _fixed_keylen);
    }

    // destroy the dbt array format
    for (int i = 0; i < _num_pivots; i++) {
        toku_destroy_dbt(&_dbt_keys[i]);
    }
    toku_free(_dbt_keys);
    _dbt_keys = nullptr;

    invariant(_fixed_format());
    sanity_check();
}

void ftnode_pivot_keys::_convert_to_dbt_format() {
    invariant(_fixed_format());

    // convert to an aray of dbts
    REALLOC_N_ALIGNED(64, _num_pivots, _dbt_keys);
    for (int i = 0; i < _num_pivots; i++) {
        toku_memdup_dbt(&_dbt_keys[i], _fixed_key(i), _fixed_keylen);
    }
    // pivots sizes are not aligned up  dbt format
    _total_size = _num_pivots * _fixed_keylen;

    // destroy the fixed key format
    toku_free(_fixed_keys);
    _fixed_keys = nullptr;
    _fixed_keylen = 0;
    _fixed_keylen_aligned = 0;

    invariant(!_fixed_format());
    sanity_check();
}

void ftnode_pivot_keys::deserialize_from_rbuf(struct rbuf *rb, int n) {
    _num_pivots = n;
    _total_size = 0;
    _fixed_keys = nullptr;
    _fixed_keylen = 0;
    _dbt_keys = nullptr;

    XMALLOC_N_ALIGNED(64, _num_pivots, _dbt_keys);
    bool keys_same_size = true;
    for (int i = 0; i < _num_pivots; i++) {
        const void *pivotkeyptr;
        uint32_t size;
        rbuf_bytes(rb, &pivotkeyptr, &size);
        toku_memdup_dbt(&_dbt_keys[i], pivotkeyptr, size);
        _total_size += size;
        if (i > 0 && keys_same_size && _dbt_keys[i].size != _dbt_keys[i - 1].size) {
            // not all keys are the same size, we'll stick to the dbt array format
            keys_same_size = false;
        }
    }

    if (keys_same_size && _num_pivots > 0) {
        _convert_to_fixed_format();
    }

    sanity_check();
}

DBT ftnode_pivot_keys::get_pivot(int i) const {
    paranoid_invariant(i < _num_pivots);
    if (_fixed_format()) {
        paranoid_invariant(i * _fixed_keylen_aligned < _total_size);
        DBT dbt;
        toku_fill_dbt(&dbt, _fixed_key(i), _fixed_keylen);
        return dbt;
    } else {
        return _dbt_keys[i];
    }
}

DBT *ftnode_pivot_keys::fill_pivot(int i, DBT *dbt) const {
    paranoid_invariant(i < _num_pivots);
    if (_fixed_format()) {
        toku_fill_dbt(dbt, _fixed_key(i), _fixed_keylen);
    } else {
        toku_copyref_dbt(dbt, _dbt_keys[i]);
    }
    return dbt;
}

void ftnode_pivot_keys::_add_key_dbt(const DBT *key, int i) {
    toku_clone_dbt(&_dbt_keys[i], *key);
    _total_size += _dbt_keys[i].size;
}

void ftnode_pivot_keys::_destroy_key_dbt(int i) {
    invariant(_total_size >= _dbt_keys[i].size);
    _total_size -= _dbt_keys[i].size;
    toku_destroy_dbt(&_dbt_keys[i]);
}

void ftnode_pivot_keys::_insert_at_dbt(const DBT *key, int i) {
    // make space for a new pivot, slide existing keys to the right
    REALLOC_N_ALIGNED(64, _num_pivots + 1, _dbt_keys);
    memmove(&_dbt_keys[i + 1], &_dbt_keys[i], (_num_pivots - i) * sizeof(DBT));
    _add_key_dbt(key, i);
}

void ftnode_pivot_keys::_insert_at_fixed(const DBT *key, int i) {
    REALLOC_N_ALIGNED(64, (_num_pivots + 1) * _fixed_keylen_aligned, _fixed_keys); 
    // TODO: This is not going to be valgrind-safe, because we do not initialize the space
    // between _fixed_keylen and _fixed_keylen_aligned (but we probably should)
    memmove(_fixed_key(i + 1), _fixed_key(i), (_num_pivots - i) * _fixed_keylen_aligned);
    memcpy(_fixed_key(i), key->data, _fixed_keylen);
    _total_size += _fixed_keylen_aligned;
}

void ftnode_pivot_keys::insert_at(const DBT *key, int i) {
    invariant(i <= _num_pivots); // it's ok to insert at the end, so we check <= n

    // if the new key doesn't have the same size, we can't be in fixed format
    if (_fixed_format() && key->size != _fixed_keylen) {
        _convert_to_dbt_format();
    }

    if (_fixed_format()) {
        _insert_at_fixed(key, i);
    } else {
        _insert_at_dbt(key, i);
    }
    _num_pivots++;

    invariant(total_size() > 0);
}

void ftnode_pivot_keys::_append_dbt(const ftnode_pivot_keys &pivotkeys) {
    REALLOC_N_ALIGNED(64, _num_pivots + pivotkeys._num_pivots, _dbt_keys);
    bool other_fixed = pivotkeys._fixed_format();
    for (int i = 0; i < pivotkeys._num_pivots; i++) {
        size_t size = other_fixed ? pivotkeys._fixed_keylen :
                                    pivotkeys._dbt_keys[i].size;
        toku_memdup_dbt(&_dbt_keys[_num_pivots + i],
                        other_fixed ? pivotkeys._fixed_key(i) :
                                      pivotkeys._dbt_keys[i].data,
                        size);
        _total_size += size;
    }
}

void ftnode_pivot_keys::_append_fixed(const ftnode_pivot_keys &pivotkeys) {
    if (pivotkeys._fixed_format() && pivotkeys._fixed_keylen == _fixed_keylen) {
        // other pivotkeys have the same fixed keylen 
        REALLOC_N_ALIGNED(64, (_num_pivots + pivotkeys._num_pivots) * _fixed_keylen_aligned, _fixed_keys);
        memcpy(_fixed_key(_num_pivots), pivotkeys._fixed_keys, pivotkeys._total_size);
        _total_size += pivotkeys._total_size;
    } else {
        // must convert to dbt format, other pivotkeys have different length'd keys
        _convert_to_dbt_format();
        _append_dbt(pivotkeys);
    }
}

void ftnode_pivot_keys::append(const ftnode_pivot_keys &pivotkeys) {
    if (_fixed_format()) {
        _append_fixed(pivotkeys);
    } else {
        _append_dbt(pivotkeys);
    }
    _num_pivots += pivotkeys._num_pivots;

    sanity_check();
}

void ftnode_pivot_keys::_replace_at_dbt(const DBT *key, int i) {
    _destroy_key_dbt(i);
    _add_key_dbt(key, i);
}

void ftnode_pivot_keys::_replace_at_fixed(const DBT *key, int i) {
    if (key->size == _fixed_keylen) {
        memcpy(_fixed_key(i), key->data, _fixed_keylen);
    } else {
        // must convert to dbt format, replacement key has different length
        _convert_to_dbt_format();
        _replace_at_dbt(key, i);
    }
}

void ftnode_pivot_keys::replace_at(const DBT *key, int i) {
    if (i < _num_pivots) {
        if (_fixed_format()) {
            _replace_at_fixed(key, i);
        } else {
            _replace_at_dbt(key, i);
        }
    } else {
        invariant(i == _num_pivots); // appending to the end is ok
        insert_at(key, i);
    }
    invariant(total_size() > 0);
}

void ftnode_pivot_keys::_delete_at_fixed(int i) {
    memmove(_fixed_key(i), _fixed_key(i + 1), (_num_pivots - 1 - i) * _fixed_keylen_aligned);
    _total_size -= _fixed_keylen_aligned;
}

void ftnode_pivot_keys::_delete_at_dbt(int i) {
    // slide over existing keys, then shrink down to size
    _destroy_key_dbt(i);
    memmove(&_dbt_keys[i], &_dbt_keys[i + 1], (_num_pivots - 1 - i) * sizeof(DBT));
    REALLOC_N_ALIGNED(64, _num_pivots - 1, _dbt_keys);
}

void ftnode_pivot_keys::delete_at(int i) {
    invariant(i < _num_pivots);

    if (_fixed_format()) {
        _delete_at_fixed(i);
    } else {
        _delete_at_dbt(i);
    }

    _num_pivots--;
}

void ftnode_pivot_keys::_split_at_fixed(int i, ftnode_pivot_keys *other) {
    // recreate the other set of pivots from index >= i
    other->_create_from_fixed_keys(_fixed_key(i), _fixed_keylen, _num_pivots - i);

    // shrink down to size
    _total_size = i * _fixed_keylen_aligned;
    REALLOC_N_ALIGNED(64, _total_size, _fixed_keys);
}

void ftnode_pivot_keys::_split_at_dbt(int i, ftnode_pivot_keys *other) {
    // recreate the other set of pivots from index >= i
    other->create_from_dbts(&_dbt_keys[i], _num_pivots - i);

    // destroy everything greater, shrink down to size
    for (int k = i; k < _num_pivots; k++) {
        _destroy_key_dbt(k);
    }
    REALLOC_N_ALIGNED(64, i, _dbt_keys);
}

void ftnode_pivot_keys::split_at(int i, ftnode_pivot_keys *other) {
    if (i < _num_pivots) {
        if (_fixed_format()) {
            _split_at_fixed(i, other);
        } else {
            _split_at_dbt(i, other);
        }
        _num_pivots = i;
    }

    sanity_check();
}

void ftnode_pivot_keys::serialize_to_wbuf(struct wbuf *wb) const {
    bool fixed = _fixed_format();
    size_t written = 0;
    for (int i = 0; i < _num_pivots; i++) {
        size_t size = fixed ? _fixed_keylen : _dbt_keys[i].size;
        invariant(size);
        wbuf_nocrc_bytes(wb, fixed ? _fixed_key(i) : _dbt_keys[i].data, size);
        written += size;
    }
    invariant(written == serialized_size());
}

int ftnode_pivot_keys::num_pivots() const {
    // if we have fixed size keys, the number of pivots should be consistent
    paranoid_invariant(_fixed_keys == nullptr || (_total_size == _fixed_keylen_aligned * _num_pivots));
    return _num_pivots;
}

size_t ftnode_pivot_keys::total_size() const {
    // if we have fixed size keys, the total size should be consistent
    paranoid_invariant(_fixed_keys == nullptr || (_total_size == _fixed_keylen_aligned * _num_pivots));
    return _total_size;
}

size_t ftnode_pivot_keys::serialized_size() const {
    // we only return the size that will be used when serialized, so we calculate based
    // on the fixed keylen and not the aligned keylen.
    return _fixed_format() ? _num_pivots * _fixed_keylen : _total_size;
}

void ftnode_pivot_keys::sanity_check() const {
    if (_fixed_format()) {
        invariant(_dbt_keys == nullptr);
        invariant(_fixed_keylen_aligned == _align4(_fixed_keylen));
        invariant(_num_pivots * _fixed_keylen <= _total_size);
        invariant(_num_pivots * _fixed_keylen_aligned == _total_size);
    } else {
        invariant(_num_pivots == 0 || _dbt_keys != nullptr);
        size_t size = 0;
        for (int i = 0; i < _num_pivots; i++) {
            size += _dbt_keys[i].size;
        }
        invariant(size == _total_size);
    }
}