Function FindBlockPos

src/main.cpp:1648–1700

}

bool FindBlockPos(CValidationState &state, CDiskBlockPos &pos, uint32_t nAddSize, uint32_t height, uint64_t nTime,
                  bool fKnown = false) {
    bool fUpdatedLast = false;

    LOCK(cs_LastBlockFile);

    if (fKnown) {
        if (nLastBlockFile != pos.nFile) {
            nLastBlockFile = pos.nFile;
            infoLastBlockFile.SetNull();
            pCdMan->pBlockIndexDb->ReadBlockFileInfo(nLastBlockFile, infoLastBlockFile);
            fUpdatedLast = true;
        }
    } else {
        while (infoLastBlockFile.nSize + nAddSize >= MAX_BLOCKFILE_SIZE) {
            LogPrint(BCLog::INFO, "Leaving block file %d: %s\n", nLastBlockFile, infoLastBlockFile.ToString());
            FlushBlockFile(true);
            nLastBlockFile++;
            infoLastBlockFile.SetNull();
            pCdMan->pBlockIndexDb->ReadBlockFileInfo(nLastBlockFile, infoLastBlockFile);  // check whether data for the new file somehow already exist; can fail just fine
            fUpdatedLast = true;
        }
        pos.nFile = nLastBlockFile;
        pos.nPos  = infoLastBlockFile.nSize;
    }

    infoLastBlockFile.nSize += nAddSize;
    infoLastBlockFile.AddBlock(height, nTime);

    if (!fKnown) {
        uint32_t nOldChunks = (pos.nPos + BLOCKFILE_CHUNK_SIZE - 1) / BLOCKFILE_CHUNK_SIZE;
        uint32_t nNewChunks = (infoLastBlockFile.nSize + BLOCKFILE_CHUNK_SIZE - 1) / BLOCKFILE_CHUNK_SIZE;
        if (nNewChunks > nOldChunks) {
            if (CheckDiskSpace(nNewChunks * BLOCKFILE_CHUNK_SIZE - pos.nPos)) {
                FILE *file = OpenBlockFile(pos);
                if (file) {
                    LogPrint(BCLog::INFO, "Pre-allocating up to position 0x%x in blk%05u.dat\n", nNewChunks * BLOCKFILE_CHUNK_SIZE, pos.nFile);
                    AllocateFileRange(file, pos.nPos, nNewChunks * BLOCKFILE_CHUNK_SIZE - pos.nPos);
                    fclose(file);
                }
            } else
                return state.Error("out of disk space");
        }
    }

    if (!pCdMan->pBlockIndexDb->WriteBlockFileInfo(nLastBlockFile, infoLastBlockFile))
        return state.Abort(_("Failed to write file info"));

    if (fUpdatedLast)
        pCdMan->pBlockCache->WriteLastBlockFile(nLastBlockFile);

    return true;
}

bool ProcessForkedChain(const CBlock &block, CBlockIndex *pPreBlockIndex, CValidationState &state) {
    bool forkChainTipFound = false;