// Copyright (c) 2024-present The Bitcoin Core developers

// Distributed under the MIT software license, see the accompanying

// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <compat/byteswap.h>

#include <crypto/common.h>

#include <logging.h>

#include <streams.h>

#include <util/translation.h>

#include <wallet/migrate.h>

#include <array>

#include <cstddef>

#include <optional>

#include <stdexcept>

#include <variant>

#include <vector>

namespace wallet {

// Magic bytes in both endianness's

constexpr uint32_t BTREE_MAGIC = 0x00053162;    // If the file endianness matches our system, we see this magic

constexpr uint32_t BTREE_MAGIC_OE = 0x62310500; // If the file endianness is the other one, we will see this magic

// Subdatabase name

static const std::vector<std::byte> SUBDATABASE_NAME = {std::byte{'m'}, std::byte{'a'}, std::byte{'i'}, std::byte{'n'}};

enum class PageType : uint8_t {

    /*

     * BDB has several page types, most of which we do not use

     * They are listed here for completeness, but commented out

     * to avoid opening something unintended.

    INVALID = 0,         // Invalid page type

    DUPLICATE = 1,       // Duplicate. Deprecated and no longer used

    HASH_UNSORTED = 2,   // Hash pages. Deprecated.

    RECNO_INTERNAL = 4,  // Recno internal

    RECNO_LEAF = 6,      // Recno leaf

    HASH_META = 8,       // Hash metadata

    QUEUE_META = 10,     // Queue Metadata

    QUEUE_DATA = 11,     // Queue Data

    DUPLICATE_LEAF = 12, // Off-page duplicate leaf

    HASH_SORTED = 13,    // Sorted hash page

    */

    BTREE_INTERNAL = 3, // BTree internal

    BTREE_LEAF = 5,     // BTree leaf

    OVERFLOW_DATA = 7,  // Overflow

    BTREE_META = 9,     // BTree metadata

};

enum class RecordType : uint8_t {

    KEYDATA = 1,

    // DUPLICATE = 2,       Unused as our databases do not support duplicate records

    OVERFLOW_DATA = 3,

    DELETE = 0x80, // Indicate this record is deleted. This is OR'd with the real type.

};

enum class BTreeFlags : uint32_t {

    /*

     * BTree databases have feature flags, but we do not use them except for

     * subdatabases. The unused flags are included for completeness, but commented out

     * to avoid accidental use.

    DUP = 1,         // Duplicates

    RECNO = 2,       // Recno tree

    RECNUM = 4,      // BTree: Maintain record counts

    FIXEDLEN = 8,    // Recno: fixed length records

    RENUMBER = 0x10, // Recno: renumber on insert/delete

    DUPSORT = 0x40,  // Duplicates are sorted

    COMPRESS = 0x80, // Compressed

    */

    SUBDB = 0x20, // Subdatabases

};

/** Berkeley DB BTree metadata page layout */

class MetaPage

{

public:

    uint32_t lsn_file;             // Log Sequence Number file

    uint32_t lsn_offset;           // Log Sequence Number offset

    uint32_t page_num;             // Current page number

    uint32_t magic;                // Magic number

    uint32_t version;              // Version

    uint32_t pagesize;             // Page size

    uint8_t encrypt_algo;          // Encryption algorithm

    PageType type;                 // Page type

    uint8_t metaflags;             // Meta-only flags

    uint8_t unused1;               // Unused

    uint32_t free_list;            // Free list page number

    uint32_t last_page;            // Page number of last page in db

    uint32_t partitions;           // Number of partitions

    uint32_t key_count;            // Cached key count

    uint32_t record_count;         // Cached record count

    BTreeFlags flags;              // Flags

    std::array<std::byte, 20> uid; // 20 byte unique file ID

    uint32_t unused2;              // Unused

    uint32_t minkey;               // Minimum key

    uint32_t re_len;               // Recno: fixed length record length

    uint32_t re_pad;               // Recno: fixed length record pad

    uint32_t root;                 // Root page number

    char unused3[368];             // 92 * 4 bytes of unused space

    uint32_t crypto_magic;         // Crypto magic number

    char trash[12];                // 3 * 4 bytes of trash space

    unsigned char iv[20];          // Crypto IV

    unsigned char chksum[16];      // Checksum

    bool other_endian;

    uint32_t expected_page_num;

    MetaPage(uint32_t expected_page_num) : expected_page_num(expected_page_num) {}

    MetaPage() = delete;

    template <typename Stream>

    void Unserialize(Stream& s)

    {

        s >> lsn_file;

        s >> lsn_offset;

        s >> page_num;

        s >> magic;

        s >> version;

        s >> pagesize;

        s >> encrypt_algo;

        other_endian = magic == BTREE_MAGIC_OE;

        uint8_t uint8_type;

        s >> uint8_type;

        type = static_cast<PageType>(uint8_type);

        s >> metaflags;

        s >> unused1;

        s >> free_list;

        s >> last_page;

        s >> partitions;

        s >> key_count;

        s >> record_count;

        uint32_t uint32_flags;

        s >> uint32_flags;

        if (other_endian) {

  Branch (137:13): [True: 0, False: 0]

            uint32_flags = internal_bswap_32(uint32_flags);

        }

        flags = static_cast<BTreeFlags>(uint32_flags);

        s >> uid;

        s >> unused2;

        s >> minkey;

        s >> re_len;

        s >> re_pad;

        s >> root;

        s >> unused3;

        s >> crypto_magic;

        s >> trash;

        s >> iv;

        s >> chksum;

        if (other_endian) {

  Branch (154:13): [True: 0, False: 0]

            lsn_file = internal_bswap_32(lsn_file);

            lsn_offset = internal_bswap_32(lsn_offset);

            page_num = internal_bswap_32(page_num);

            magic = internal_bswap_32(magic);

            version = internal_bswap_32(version);

            pagesize = internal_bswap_32(pagesize);

            free_list = internal_bswap_32(free_list);

            last_page = internal_bswap_32(last_page);

            partitions = internal_bswap_32(partitions);

            key_count = internal_bswap_32(key_count);

            record_count = internal_bswap_32(record_count);

            unused2 = internal_bswap_32(unused2);

            minkey = internal_bswap_32(minkey);

            re_len = internal_bswap_32(re_len);

            re_pad = internal_bswap_32(re_pad);

            root = internal_bswap_32(root);

            crypto_magic = internal_bswap_32(crypto_magic);

        }

        // Page number must match

        if (page_num != expected_page_num) {

  Branch (175:13): [True: 0, False: 0]

            throw std::runtime_error("Meta page number mismatch");

        }

        // Check magic

        if (magic != BTREE_MAGIC) {

  Branch (180:13): [True: 0, False: 0]

            throw std::runtime_error("Not a BDB file");

        }

        // Only version 9 is supported

        if (version != 9) {

  Branch (185:13): [True: 0, False: 0]

            throw std::runtime_error("Unsupported BDB data file version number");

        }

        // Page size must be 512 <= pagesize <= 64k, and be a power of 2

        if (pagesize < 512 || pagesize > 65536 || (pagesize & (pagesize - 1)) != 0) {

  Branch (190:13): [True: 0, False: 0]
  Branch (190:31): [True: 0, False: 0]
  Branch (190:51): [True: 0, False: 0]

            throw std::runtime_error("Bad page size");

        }

        // Page type must be the btree type

        if (type != PageType::BTREE_META) {

  Branch (195:13): [True: 0, False: 0]

            throw std::runtime_error("Unexpected page type, should be 9 (BTree Metadata)");

        }

        // Only supported meta-flag is subdatabase

        if (flags != BTreeFlags::SUBDB) {

  Branch (200:13): [True: 0, False: 0]

            throw std::runtime_error("Unexpected database flags, should only be 0x20 (subdatabases)");

        }

    }

};

/** General class for records in a BDB BTree database. Contains common fields. */

class RecordHeader

{

public:

    uint16_t len;    // Key/data item length

    RecordType type; // Page type (BDB has this include a DELETE FLAG that we track separately)

    bool deleted;    // Whether the DELETE flag was set on type

    static constexpr size_t SIZE = 3; // The record header is 3 bytes

    bool other_endian;

    RecordHeader(bool other_endian) : other_endian(other_endian) {}

    RecordHeader() = delete;

    template <typename Stream>

    void Unserialize(Stream& s)

    {

        s >> len;

        uint8_t uint8_type;

        s >> uint8_type;

        type = static_cast<RecordType>(uint8_type & ~static_cast<uint8_t>(RecordType::DELETE));

        deleted = uint8_type & static_cast<uint8_t>(RecordType::DELETE);

        if (other_endian) {

  Branch (231:13): [True: 0, False: 0]

            len = internal_bswap_16(len);

        }

    }

};

/** Class for data in the record directly */

class DataRecord

{

public:

    DataRecord(const RecordHeader& header) : m_header(header) {}

    DataRecord() = delete;

    RecordHeader m_header;

    std::vector<std::byte> data; // Variable length key/data item

    template <typename Stream>

    void Unserialize(Stream& s)

    {

        data.resize(m_header.len);

        s.read(std::as_writable_bytes(std::span(data.data(), data.size())));

    }

};

/** Class for records representing internal nodes of the BTree. */

class InternalRecord

{

public:

    InternalRecord(const RecordHeader& header) : m_header(header) {}

    InternalRecord() = delete;

    RecordHeader m_header;

    uint8_t unused;              // Padding, unused

    uint32_t page_num;           // Page number of referenced page

    uint32_t records;            // Subtree record count

    std::vector<std::byte> data; // Variable length key item

    static constexpr size_t FIXED_SIZE = 9; // Size of fixed data is 9 bytes

    template <typename Stream>

    void Unserialize(Stream& s)

    {

        s >> unused;

        s >> page_num;

        s >> records;

        data.resize(m_header.len);

        s.read(std::as_writable_bytes(std::span(data.data(), data.size())));

        if (m_header.other_endian) {

  Branch (282:13): [True: 0, False: 0]

            page_num = internal_bswap_32(page_num);

            records = internal_bswap_32(records);

        }

    }

};

/** Class for records representing overflow records of the BTree.

 * Overflow records point to a page which contains the data in the record.

 * Those pages may point to further pages with the rest of the data if it does not fit

 * in one page */

class OverflowRecord

{

public:

    OverflowRecord(const RecordHeader& header) : m_header(header) {}

    OverflowRecord() = delete;

    RecordHeader m_header;

    uint8_t unused2;      // Padding, unused

    uint32_t page_number; // Page number where data begins

    uint32_t item_len;    // Total length of item

    static constexpr size_t SIZE = 9; // Overflow record is always 9 bytes

    template <typename Stream>

    void Unserialize(Stream& s)

    {

        s >> unused2;

        s >> page_number;

        s >> item_len;

        if (m_header.other_endian) {

  Branch (314:13): [True: 0, False: 0]

            page_number = internal_bswap_32(page_number);

            item_len = internal_bswap_32(item_len);

        }

    }

};

/** A generic data page in the database. Contains fields common to all data pages. */

class PageHeader

{

public:

    uint32_t lsn_file;   // Log Sequence Number file

    uint32_t lsn_offset; // Log Sequence Number offset

    uint32_t page_num;   // Current page number

    uint32_t prev_page;  // Previous page number

    uint32_t next_page;  // Next page number

    uint16_t entries;    // Number of items on the page

    uint16_t hf_offset;  // High free byte page offset

    uint8_t level;       // Btree page level

    PageType type;       // Page type

    static constexpr int64_t SIZE = 26; // The header is 26 bytes

    uint32_t expected_page_num;

    bool other_endian;

    PageHeader(uint32_t page_num, bool other_endian) : expected_page_num(page_num), other_endian(other_endian) {}

    PageHeader() = delete;

    template <typename Stream>

    void Unserialize(Stream& s)

    {

        s >> lsn_file;

        s >> lsn_offset;

        s >> page_num;

        s >> prev_page;

        s >> next_page;

        s >> entries;

        s >> hf_offset;

        s >> level;

        uint8_t uint8_type;

        s >> uint8_type;

        type = static_cast<PageType>(uint8_type);

        if (other_endian) {

  Branch (359:13): [True: 0, False: 0]

            lsn_file = internal_bswap_32(lsn_file);

            lsn_offset = internal_bswap_32(lsn_offset);

            page_num = internal_bswap_32(page_num);

            prev_page = internal_bswap_32(prev_page);

            next_page = internal_bswap_32(next_page);

            entries = internal_bswap_16(entries);

            hf_offset = internal_bswap_16(hf_offset);

        }

        if (expected_page_num != page_num) {

  Branch (369:13): [True: 0, False: 0]

            throw std::runtime_error("Page number mismatch");

        }

        if ((type != PageType::OVERFLOW_DATA && level < 1) || (type == PageType::OVERFLOW_DATA && level != 0)) {

  Branch (372:14): [True: 0, False: 0]
  Branch (372:49): [True: 0, False: 0]
  Branch (372:64): [True: 0, False: 0]
  Branch (372:99): [True: 0, False: 0]

            throw std::runtime_error("Bad btree level");

        }

    }

};

/** A page of records in the database */

class RecordsPage

{

public:

    RecordsPage(const PageHeader& header) : m_header(header) {}

    RecordsPage() = delete;

    PageHeader m_header;

    std::vector<uint16_t> indexes;

    std::vector<std::variant<DataRecord, OverflowRecord>> records;

    template <typename Stream>

    void Unserialize(Stream& s)

    {

        // Current position within the page

        int64_t pos = PageHeader::SIZE;

        // Get the items

        for (uint32_t i = 0; i < m_header.entries; ++i) {

  Branch (397:30): [True: 0, False: 0]

            // Get the index

            uint16_t index;

            s >> index;

            if (m_header.other_endian) {

  Branch (401:17): [True: 0, False: 0]

                index = internal_bswap_16(index);

            }

            indexes.push_back(index);

            pos += sizeof(uint16_t);

            // Go to the offset from the index

            int64_t to_jump = index - pos;

            if (to_jump < 0) {

  Branch (409:17): [True: 0, False: 0]

                throw std::runtime_error("Data record position not in page");

            }

            s.ignore(to_jump);

            // Read the record

            RecordHeader rec_hdr(m_header.other_endian);

            s >> rec_hdr;

            to_jump += RecordHeader::SIZE;

            switch (rec_hdr.type) {

            case RecordType::KEYDATA: {

  Branch (420:13): [True: 0, False: 0]

                DataRecord record(rec_hdr);

                s >> record;

                records.emplace_back(record);

                to_jump += rec_hdr.len;

                break;

            }

            case RecordType::OVERFLOW_DATA: {

  Branch (427:13): [True: 0, False: 0]

                OverflowRecord record(rec_hdr);

                s >> record;

                records.emplace_back(record);

                to_jump += OverflowRecord::SIZE;

                break;

            }

            default:

  Branch (434:13): [True: 0, False: 0]

                throw std::runtime_error("Unknown record type in records page");

            }

            // Go back to the indexes

            s.seek(-to_jump, SEEK_CUR);

        }

    }

};

/** A page containing overflow data */

class OverflowPage

{

public:

    OverflowPage(const PageHeader& header) : m_header(header) {}

    OverflowPage() = delete;

    PageHeader m_header;

    // BDB overloads some page fields to store overflow page data

    // hf_offset contains the length of the overflow data stored on this page

    // entries contains a reference count for references to this item

    // The overflow data itself. Begins immediately following header

    std::vector<std::byte> data;

    template <typename Stream>

    void Unserialize(Stream& s)

    {

        data.resize(m_header.hf_offset);

        s.read(std::as_writable_bytes(std::span(data.data(), data.size())));

    }

};

/** A page of records in the database */

class InternalPage

{

public:

    InternalPage(const PageHeader& header) : m_header(header) {}

    InternalPage() = delete;

    PageHeader m_header;

    std::vector<uint16_t> indexes;

    std::vector<InternalRecord> records;

    template <typename Stream>

    void Unserialize(Stream& s)

    {

        // Current position within the page

        int64_t pos = PageHeader::SIZE;

        // Get the items

        for (uint32_t i = 0; i < m_header.entries; ++i) {

  Branch (487:30): [True: 0, False: 0]

            // Get the index

            uint16_t index;

            s >> index;

            if (m_header.other_endian) {

  Branch (491:17): [True: 0, False: 0]

                index = internal_bswap_16(index);

            }

            indexes.push_back(index);

            pos += sizeof(uint16_t);

            // Go to the offset from the index

            int64_t to_jump = index - pos;

            if (to_jump < 0) {

  Branch (499:17): [True: 0, False: 0]

                throw std::runtime_error("Internal record position not in page");

            }

            s.ignore(to_jump);

            // Read the record

            RecordHeader rec_hdr(m_header.other_endian);

            s >> rec_hdr;

            to_jump += RecordHeader::SIZE;

            if (rec_hdr.type != RecordType::KEYDATA) {

  Branch (509:17): [True: 0, False: 0]

                throw std::runtime_error("Unknown record type in internal page");

            }

            InternalRecord record(rec_hdr);

            s >> record;

            records.emplace_back(record);

            to_jump += InternalRecord::FIXED_SIZE + rec_hdr.len;

            // Go back to the indexes

            s.seek(-to_jump, SEEK_CUR);

        }

    }

};

static void SeekToPage(AutoFile& s, uint32_t page_num, uint32_t page_size)

{

    int64_t pos = int64_t{page_num} * page_size;

    s.seek(pos, SEEK_SET);

}

void BerkeleyRODatabase::Open()

{

    // Open the file

    FILE* file = fsbridge::fopen(m_filepath, "rb");

    AutoFile db_file(file);

    if (db_file.IsNull()) {

  Branch (534:9): [True: 0, False: 0]

        throw std::runtime_error("BerkeleyRODatabase: Failed to open database file");

    }

    uint32_t page_size = 4096; // Default page size

    // Read the outer metapage

    // Expected page number is 0

    MetaPage outer_meta(0);

    db_file >> outer_meta;

    page_size = outer_meta.pagesize;

    // Verify the size of the file is a multiple of the page size

    db_file.seek(0, SEEK_END);

    int64_t size = db_file.tell();

    // Since BDB stores everything in a page, the file size should be a multiple of the page size;

    // However, BDB doesn't actually check that this is the case, and enforcing this check results

    // in us rejecting a database that BDB would not, so this check needs to be excluded.

    // This is left commented out as a reminder to not accidentally implement this in the future.

    // if (size % page_size != 0) {

    //     throw std::runtime_error("File size is not a multiple of page size");

    // }

    // Check the last page number

    uint32_t expected_last_page{uint32_t((size / page_size) - 1)};

    if (outer_meta.last_page != expected_last_page) {

  Branch (560:9): [True: 0, False: 0]

        throw std::runtime_error("Last page number could not fit in file");

    }

    // Make sure encryption is disabled

    if (outer_meta.encrypt_algo != 0) {

  Branch (565:9): [True: 0, False: 0]

        throw std::runtime_error("BDB builtin encryption is not supported");

    }

    // Check all Log Sequence Numbers (LSN) point to file 0 and offset 1 which indicates that the LSNs were

    // reset and that the log files are not necessary to get all of the data in the database.

    for (uint32_t i = 0; i < outer_meta.last_page; ++i) {

  Branch (571:26): [True: 0, False: 0]

        // The LSN is composed of 2 32-bit ints, the first is a file id, the second an offset

        // It will always be the first 8 bytes of a page, so we deserialize it directly for every page

        uint32_t file;

        uint32_t offset;

        SeekToPage(db_file, i, page_size);

        db_file >> file >> offset;

        if (outer_meta.other_endian) {

  Branch (578:13): [True: 0, False: 0]

            file = internal_bswap_32(file);

            offset = internal_bswap_32(offset);

        }

        if (file != 0 || offset != 1) {

  Branch (582:13): [True: 0, False: 0]
  Branch (582:26): [True: 0, False: 0]

            throw std::runtime_error("LSNs are not reset, this database is not completely flushed. Please reopen then close the database with a version that has BDB support");

        }

    }

    // Read the root page

    SeekToPage(db_file, outer_meta.root, page_size);

    PageHeader header(outer_meta.root, outer_meta.other_endian);

    db_file >> header;

    if (header.type != PageType::BTREE_LEAF) {

  Branch (591:9): [True: 0, False: 0]

        throw std::runtime_error("Unexpected outer database root page type");

    }

    if (header.entries != 2) {

  Branch (594:9): [True: 0, False: 0]

        throw std::runtime_error("Unexpected number of entries in outer database root page");

    }

    RecordsPage page(header);

    db_file >> page;

    // First record should be the string "main"

    if (!std::holds_alternative<DataRecord>(page.records.at(0)) || std::get<DataRecord>(page.records.at(0)).data != SUBDATABASE_NAME) {

  Branch (601:9): [True: 0, False: 0]
  Branch (601:68): [True: 0, False: 0]

        throw std::runtime_error("Subdatabase has an unexpected name");

    }

    // Check length of page number for subdatabase location

    if (!std::holds_alternative<DataRecord>(page.records.at(1)) || std::get<DataRecord>(page.records.at(1)).m_header.len != 4) {

  Branch (605:9): [True: 0, False: 0]
  Branch (605:68): [True: 0, False: 0]

        throw std::runtime_error("Subdatabase page number has unexpected length");

    }

    // Read subdatabase page number

    // It is written as a big endian 32 bit number

    uint32_t main_db_page = ReadBE32(std::get<DataRecord>(page.records.at(1)).data.data());

    // The main database is in a page that doesn't exist

    if (main_db_page > outer_meta.last_page) {

  Branch (614:9): [True: 0, False: 0]

        throw std::runtime_error("Page number is greater than database last page");

    }

    // Read the inner metapage

    SeekToPage(db_file, main_db_page, page_size);

    MetaPage inner_meta(main_db_page);

    db_file >> inner_meta;

    if (inner_meta.pagesize != page_size) {

  Branch (623:9): [True: 0, False: 0]

        throw std::runtime_error("Unexpected page size");

    }

    if (inner_meta.last_page > outer_meta.last_page) {

  Branch (627:9): [True: 0, False: 0]

        throw std::runtime_error("Subdatabase last page is greater than database last page");

    }

    // Make sure encryption is disabled

    if (inner_meta.encrypt_algo != 0) {

  Branch (632:9): [True: 0, False: 0]

        throw std::runtime_error("BDB builtin encryption is not supported");

    }

    // Do a DFS through the BTree, starting at root

    std::vector<uint32_t> pages{inner_meta.root};

    while (pages.size() > 0) {

  Branch (638:12): [True: 0, False: 0]

        uint32_t curr_page = pages.back();

        // It turns out BDB completely ignores this last_page field and doesn't actually update it to the correct

        // last page. While we should be checking this, we can't.

        // This is left commented out as a reminder to not accidentally implement this in the future.

        // if (curr_page > inner_meta.last_page) {

        //     throw std::runtime_error("Page number is greater than subdatabase last page");

        // }

        pages.pop_back();

        SeekToPage(db_file, curr_page, page_size);

        PageHeader header(curr_page, inner_meta.other_endian);

        db_file >> header;

        switch (header.type) {

        case PageType::BTREE_INTERNAL: {

  Branch (651:9): [True: 0, False: 0]

            InternalPage int_page(header);

            db_file >> int_page;

            for (const InternalRecord& rec : int_page.records) {

  Branch (654:44): [True: 0, False: 0]

                if (rec.m_header.deleted) continue;

  Branch (655:21): [True: 0, False: 0]

                pages.push_back(rec.page_num);

            }

            break;

        }

        case PageType::BTREE_LEAF: {

  Branch (660:9): [True: 0, False: 0]

            RecordsPage rec_page(header);

            db_file >> rec_page;

            if (rec_page.records.size() % 2 != 0) {

  Branch (663:17): [True: 0, False: 0]

                // BDB stores key value pairs in consecutive records, thus an odd number of records is unexpected

                throw std::runtime_error("Records page has odd number of records");

            }

            bool is_key = true;

            std::vector<std::byte> key;

            for (const std::variant<DataRecord, OverflowRecord>& rec : rec_page.records) {

  Branch (669:70): [True: 0, False: 0]

                std::vector<std::byte> data;

                if (const DataRecord* drec = std::get_if<DataRecord>(&rec)) {

  Branch (671:39): [True: 0, False: 0]

                    if (drec->m_header.deleted) continue;

  Branch (672:25): [True: 0, False: 0]

                    data = drec->data;

                } else if (const OverflowRecord* orec = std::get_if<OverflowRecord>(&rec)) {

  Branch (674:50): [True: 0, False: 0]

                    if (orec->m_header.deleted) continue;

  Branch (675:25): [True: 0, False: 0]

                    uint32_t next_page = orec->page_number;

                    while (next_page != 0) {

  Branch (677:28): [True: 0, False: 0]

                        SeekToPage(db_file, next_page, page_size);

                        PageHeader opage_header(next_page, inner_meta.other_endian);

                        db_file >> opage_header;

                        if (opage_header.type != PageType::OVERFLOW_DATA) {

  Branch (681:29): [True: 0, False: 0]

                            throw std::runtime_error("Bad overflow record page type");

                        }

                        OverflowPage opage(opage_header);

                        db_file >> opage;

                        data.insert(data.end(), opage.data.begin(), opage.data.end());

                        next_page = opage_header.next_page;

                    }

                }

                if (is_key) {

  Branch (691:21): [True: 0, False: 0]

                    key = data;

                } else {

                    m_records.emplace(SerializeData{key.begin(), key.end()}, SerializeData{data.begin(), data.end()});

                    key.clear();

                }

                is_key = !is_key;

            }

            break;

        }

        default:

  Branch (701:9): [True: 0, False: 0]

            throw std::runtime_error("Unexpected page type");

        }

    }

}

std::unique_ptr<DatabaseBatch> BerkeleyRODatabase::MakeBatch()

{

    return std::make_unique<BerkeleyROBatch>(*this);

}

bool BerkeleyRODatabase::Backup(const std::string& dest) const

{

    fs::path src(m_filepath);

    fs::path dst(fs::PathFromString(dest));

    if (fs::is_directory(dst)) {

  Branch (717:9): [True: 0, False: 0]

        dst = BDBDataFile(dst);

    }

    try {

        if (fs::exists(dst) && fs::equivalent(src, dst)) {

  Branch (721:13): [True: 0, False: 0]
  Branch (721:32): [True: 0, False: 0]

            LogPrintf("cannot backup to wallet source file %s\n", fs::PathToString(dst));

            return false;

        }

        fs::copy_file(src, dst, fs::copy_options::overwrite_existing);

        LogPrintf("copied %s to %s\n", fs::PathToString(m_filepath), fs::PathToString(dst));

        return true;

    } catch (const fs::filesystem_error& e) {

        LogWarning("error copying %s to %s - %s\n", fs::PathToString(m_filepath), fs::PathToString(dst), e.code().message());

        return false;

    }

}

bool BerkeleyROBatch::ReadKey(DataStream&& key, DataStream& value)

{

    SerializeData key_data{key.begin(), key.end()};

    const auto it{m_database.m_records.find(key_data)};

    if (it == m_database.m_records.end()) {

  Branch (739:9): [True: 0, False: 0]

        return false;

    }

    auto val = it->second;

    value.clear();

    value.write(std::span(val));

    return true;

}

bool BerkeleyROBatch::HasKey(DataStream&& key)

{

    SerializeData key_data{key.begin(), key.end()};

    return m_database.m_records.count(key_data) > 0;

}

BerkeleyROCursor::BerkeleyROCursor(const BerkeleyRODatabase& database, std::span<const std::byte> prefix)

    : m_database(database)

{

    std::tie(m_cursor, m_cursor_end) = m_database.m_records.equal_range(BytePrefix{prefix});

}

DatabaseCursor::Status BerkeleyROCursor::Next(DataStream& ssKey, DataStream& ssValue)

{

    if (m_cursor == m_cursor_end) {

  Branch (762:9): [True: 0, False: 0]

        return DatabaseCursor::Status::DONE;

    }

    ssKey.write(std::span(m_cursor->first));

    ssValue.write(std::span(m_cursor->second));

    m_cursor++;

    return DatabaseCursor::Status::MORE;

}

std::unique_ptr<DatabaseCursor> BerkeleyROBatch::GetNewPrefixCursor(std::span<const std::byte> prefix)

{

    return std::make_unique<BerkeleyROCursor>(m_database, prefix);

}

std::unique_ptr<BerkeleyRODatabase> MakeBerkeleyRODatabase(const fs::path& path, const DatabaseOptions& options, DatabaseStatus& status, bilingual_str& error)

{

    fs::path data_file = BDBDataFile(path);

    try {

        std::unique_ptr<BerkeleyRODatabase> db = std::make_unique<BerkeleyRODatabase>(data_file);

        status = DatabaseStatus::SUCCESS;

        return db;

    } catch (const std::runtime_error& e) {

        error.original = e.what();

        status = DatabaseStatus::FAILED_LOAD;

        return nullptr;

    }

}

} // namespace wallet