函数flst_add_last

/********************************************************************//**
Adds a node as the last node in a list. */
UNIV_INTERN
void
flst_add_last(
/*==========*/
    flst_base_node_t*    base,    /*!< in: pointer to base node of list */
    flst_node_t*        node,    /*!< in: node to add */
    mtr_t*            mtr)    /*!< in: mini-transaction handle */
{
    ulint        space;
    fil_addr_t    node_addr;
    ulint        len;
    fil_addr_t    last_addr;
    flst_node_t*    last_node;
 
    ut_ad(mtr && base && node);
    ut_ad(base != node);
    ut_ad(mtr_memo_contains_page(mtr, base, MTR_MEMO_PAGE_X_FIX));
    ut_ad(mtr_memo_contains_page(mtr, node, MTR_MEMO_PAGE_X_FIX));
    len = flst_get_len(base, mtr);
    last_addr = flst_get_last(base, mtr); //获得base的FLST_LAST最后一个节点的page,offset
 
    buf_ptr_get_fsp_addr(node, &space, &node_addr);//返回file page 中的space, page_no,page_offset 详见    /* If the list is not empty, call flst_insert_after */
    ) {
        if (last_addr.page == node_addr.page) {
            last_node = page_align(node) + last_addr.boffset;
        } else {
            ulint    zip_size = fil_space_get_zip_size(space);
 
            last_node = fut_get_ptr(space, zip_size, last_addr,
                        RW_X_LATCH, mtr);
        }
 
        flst_insert_after(base, last_node, node, mtr);
    } else {
        /* else call flst_add_to_empty */
        flst_add_to_empty(base, node, mtr);
    }
}

/********************************************************************//**
Inserts a node after another in a list. */
UNIV_INTERN
void
flst_insert_after(
/*==============*/
    flst_base_node_t*    base,    /*!< in: pointer to base node of list */
    flst_node_t*        node1,    /*!< in: node to insert after */
    flst_node_t*        node2,    /*!< in: node to add */
    mtr_t*            mtr)    /*!< in: mini-transaction handle */
{
    ulint        space;
    fil_addr_t    node1_addr;
    fil_addr_t    node2_addr;
    flst_node_t*    node3;
    fil_addr_t    node3_addr;
    ulint        len;
 
    ut_ad(mtr && node1 && node2 && base);
    ut_ad(base != node1);
    ut_ad(base != node2);
    ut_ad(node2 != node1);
    ut_ad(mtr_memo_contains_page(mtr, base, MTR_MEMO_PAGE_X_FIX));
    ut_ad(mtr_memo_contains_page(mtr, node1, MTR_MEMO_PAGE_X_FIX));
    ut_ad(mtr_memo_contains_page(mtr, node2, MTR_MEMO_PAGE_X_FIX));
 
    buf_ptr_get_fsp_addr(node1, &space, &node1_addr);
    buf_ptr_get_fsp_addr(node2, &space, &node2_addr);
 
    node3_addr = flst_get_next_addr(node1, mtr);
 
    /* Set prev and next fields of node2 */
    flst_write_addr(node2 + FLST_PREV, node1_addr, mtr);
    flst_write_addr(node2 + FLST_NEXT, node3_addr, mtr);
 
    if (!fil_addr_is_null(node3_addr)) {
        /* Update prev field of node3 */
        ulint    zip_size = fil_space_get_zip_size(space);
 
        node3 = fut_get_ptr(space, zip_size,
                    node3_addr, RW_X_LATCH, mtr);
        flst_write_addr(node3 + FLST_PREV, node2_addr, mtr);
    } else {
        /* node1 was last in list: update last field in base */
        flst_write_addr(base + FLST_LAST, node2_addr, mtr);
    }
 
    /* Set next field of node1 */
    flst_write_addr(node1 + FLST_NEXT, node2_addr, mtr);
 
    /* Update len of base node */
    len = flst_get_len(base, mtr);
    mlog_write_ulint(, MLOG_4BYTES, mtr);
}