class.cpp

FastDb是高效的内存数据库系统

  indexedFields = NULL;

  inverseFields = NULL;

  tableId = 0;

  nFields = 0;

  nColumns = 0;

  db = database;

  fixedDatabase = database != NULL;

  fixedSize = sizeof(dbRecord);

  int attr = dbFieldDescriptor::OneToOneMapping;

  appSize = 0;

  autoincrementCount = initialAutoincrementCount;

  size_t maxAlignment = calculateFieldsAttributes(columns, "",
                        sizeof(dbRecord),
                        HASHED|INDEXED, attr);

#if CHECK_RECORD_SIZE

  appSize = DOALIGN(appSize, maxAlignment);

  if (appSize < objSize)
  {
    fprintf(stderr, "Warning: may be not all fields of the class '%s' "
            "were described\n", name);
  }

#endif
  *nextFieldLink = NULL;
}


int dbTableDescriptor::calculateFieldsAttributes(dbFieldDescriptor* first,
    char const*        prefix,
    int                offs,
    int                indexMask,
    int&               attr)
{
  dbFieldDescriptor *field = first;
  size_t alignment = 1;

  do
  {
    if (field->method)
    {
      assert(((void)"Not empty record", field != first));

      do
      {
        assert(((void)"Methods should be specified after variables",
                field->method != NULL));
        field->dbsOffs = first->dbsOffs;
        field->components = first;

        if (attr & dbFieldDescriptor::OneToOneMapping)
        {
          field->method = field->method->optimize();
        }
      }
      while ((field = field->next) != first);

      break;
    }

    if (*prefix != '\0')
    {
      char* p = new char[strlen(prefix)+strlen(field->name)+1];
      sprintf(p, "%s%s", prefix, field->name);
      field->longName = p;
    }
    else
    {
      nColumns += 1;
      field->longName = new char[strlen(field->name)+1];
      strcpy(field->longName, field->name);
    }

    field->defTable = this;
    field->indexType &= indexMask|DB_FIELD_INHERITED_MASK;
    field->attr = (attr & dbFieldDescriptor::ComponentOfArray)
                  | dbFieldDescriptor::OneToOneMapping;

    if (field->inverseRefName)
    {
      assert(!(attr & dbFieldDescriptor::ComponentOfArray)
             && (field->type == dbField::tpReference
                 || (field->type == dbField::tpArray
                     && field->components->type==dbField::tpReference)));
      field->nextInverseField = inverseFields;
      inverseFields = field;
    }

    *nextFieldLink = field;
    nextFieldLink = &field->nextField;
    field->fieldNo = nFields++;

    switch (field->type)
    {

    case dbField::tpArray:
      {
        size_t saveOffs = fixedSize;
        size_t saveAppSize = appSize;
        fixedSize = 0;
        attr = (attr | dbFieldDescriptor::HasArrayComponents)
               & ~dbFieldDescriptor::OneToOneMapping;
        field->attr |= dbFieldDescriptor::ComponentOfArray;
        calculateFieldsAttributes(field->components, field->longName,
                                  0, 0, field->attr);

        if (field->components->dbsSize != field->components->appSize)
        {
          field->attr &= ~dbFieldDescriptor::OneToOneMapping;
        }

        fixedSize = saveOffs;
        appSize = DOALIGN(saveAppSize, sizeof(void*))
                  + sizeof(void*)*3;
        break;
      }

    case dbField::tpStructure:
      {
        char* aggregateName = new char[strlen(field->longName) + 2];
        sprintf(aggregateName, "%s.", field->longName);
        size_t saveOffs = fixedSize;
        size_t saveAppSize = appSize;
        appSize = 0;
        size_t struct_alignment =
          calculateFieldsAttributes(field->components,
                                    aggregateName,
                                    offs + field->appOffs,
                                    field->indexType,
                                    field->attr);
        field->alignment = struct_alignment;
        field->dbsOffs = field->components->dbsOffs;
        attr |= field->attr & dbFieldDescriptor::HasArrayComponents;
        attr &= field->attr | ~dbFieldDescriptor::OneToOneMapping;
        field->dbsSize = DOALIGN(fixedSize-saveOffs, struct_alignment);

        if ((field->attr & dbFieldDescriptor::HasArrayComponents)
            && struct_alignment < sizeof(void*))
        {
          struct_alignment = sizeof(void*);
        }

        appSize = DOALIGN(appSize, struct_alignment)
                  + DOALIGN(saveAppSize, struct_alignment);
        delete[] aggregateName;
        break;
      }

    case dbField::tpString:
      attr = (attr | dbFieldDescriptor::HasArrayComponents)
             & ~dbFieldDescriptor::OneToOneMapping;
      // no break

    default:
      appSize = DOALIGN(appSize, field->appSize) + field->appSize;
    }

    if (alignment < field->alignment)
    {
      alignment = field->alignment;
    }

    if (field->type != dbField::tpStructure)
    {
      field->dbsOffs = fixedSize = DOALIGN(fixedSize, field->alignment);
      fixedSize += field->dbsSize;

      if (field->dbsOffs != offs + field->appOffs)
      {
        attr &= ~dbFieldDescriptor::OneToOneMapping;
      }

      if (field->indexType & (HASHED|INDEXED))
      {
        assert(!(field->attr & dbFieldDescriptor::ComponentOfArray));

        if (field->indexType & HASHED)
        {
          field->nextHashedField = hashedFields;
          hashedFields = field;
        }

        if (field->indexType & INDEXED)
        {
          field->nextIndexedField = indexedFields;
          indexedFields = field;
        }
      }
    }
  }
  while ((field = field->next) != first);

  return alignment;
}


int dbFieldDescriptor::sizeWithoutOneField(dbFieldDescriptor* field,
    byte* base, size_t& size)
{
  dbFieldDescriptor* fd = this;
  int offs, last = 0;

  do
  {
    if (fd != field)
    {
      if (fd->type == dbField::tpArray || fd->type == dbField::tpString)
      {
        dbVarying* arr = (dbVarying*)(base + fd->dbsOffs);

        if (arr->offs > last)
        {
          last = arr->offs;
        }

        int n = arr->size;
        size = DOALIGN(size, fd->components->alignment)
               + fd->components->dbsSize * n;

        if (fd->attr & HasArrayComponents)
        {
          byte* elem = base + arr->offs;

          while (--n >= 0)
          {
            offs = fd->components->sizeWithoutOneField(field,
                   elem, size);

            if (arr->offs + offs > last)
            {
              last = arr->offs + offs;
            }

            elem += fd->components->dbsSize;
          }
        }
      }
      else if (fd->attr & HasArrayComponents)
      {
        offs = fd->components->sizeWithoutOneField(field, base, size);

        if (offs > last)
        {
          last = offs;
        }
      }
    }
  }
  while ((fd = fd->next) != this);

  return last;
}


size_t dbFieldDescriptor::copyRecordExceptOneField(dbFieldDescriptor* field,
    byte* dst, byte* src,
    size_t offs)
{
  dbFieldDescriptor* fd = this;

  do
  {
    if (fd != field)
    {
      if (fd->type == dbField::tpArray || fd->type == dbField::tpString)
      {
        dbVarying* srcArr = (dbVarying*)(src + fd->dbsOffs);
        dbVarying* dstArr = (dbVarying*)(dst + fd->dbsOffs);
        int n = srcArr->size;
        byte* srcElem = src + srcArr->offs;
        offs = DOALIGN(offs, fd->components->alignment);
        byte* dstElem = dst + offs;
        dstArr->offs = offs;
        dstArr->size = n;
        size_t sizeElem = fd->components->dbsSize;
        size_t offsElem = sizeElem * n;
        offs += offsElem;

        if (fd->attr & HasArrayComponents)
        {
          while (--n >= 0)
          {
            offsElem = fd->components->
                       copyRecordExceptOneField(field, dstElem, srcElem,
                                                offsElem);
            offsElem -= sizeElem;
            dstElem += sizeElem;
            srcElem += sizeElem;
          }

          offs += offsElem;
        }
        else
        {
          memcpy(dstElem, srcElem, offsElem);
        }
      }
      else if (fd->attr & HasArrayComponents)
      {
        offs = fd->components->copyRecordExceptOneField(field, dst,
               src, offs);
      }
      else if (fd->method == NULL)
      {
        memcpy(dst+fd->dbsOffs, src+fd->dbsOffs, fd->dbsSize);
      }
    }
  }
  while ((fd = fd->next) != this);

  return offs;
}


void dbTableDescriptor::checkRelationship()
{
  dbFieldDescriptor* fd;

  for (fd = inverseFields; fd != NULL; fd = fd->nextInverseField)
  {
    dbTableDescriptor* refTable =
      fd->refTable ? fd->refTable : fd->components->refTable;
    fd->inverseRef = refTable->findSymbol(fd->inverseRefName);

    if (fd->inverseRef == NULL
        || fd->inverseRef->inverseRefName != fd->name)
    {
      char msg[256];

      if (fd->inverseRef == NULL)
      {
        sprintf(msg, "Failed to locate inverse reference field %s.%s for field %s.%s",
                refTable->name, fd->inverseRefName, fd->defTable->name, fd->longName);
      }
      else
      {
        sprintf(msg, "Inverse references for field %s.%s is %s.%s, but its inverse reference is %s",
                fd->defTable->name, fd->longName, refTable->name, fd->inverseRefName, fd->inverseRef->inverseRefName);
      }

      db->handleError(dbDatabase::InconsistentInverseReference, msg);
    }
  }
}

dbFieldDescriptor* dbTableDescriptor::find(char const* name)
{
  char* symnam = (char*)name;

  dbSymbolTable::add
    (symnam, tkn_ident);

  return findSymbol(symnam);
}

dbFieldDescriptor* dbTableDescriptor::findSymbol(const char* name)
{
  dbFieldDescriptor* first = columns;
  dbFieldDescriptor* field = first;

  do
  {
    if (field->name == name)
    {
      return field;
    }
  }
  while ((field = field->next) != first);

  return NULL;
}

dbFieldDescriptor& dbFieldDescriptor::adjustOffsets(long offs)
{
  if (offs != 0)
  {
    dbFieldDescriptor* fd = this;

    do
    {
      fd->appOffs += offs;
    }
    while ((fd = fd->next) != this);
  }

  return *this;
}




bool dbTableDescriptor::match(dbTable* table, bool confirmDeleteColumns)
{
  unsigned nFields = table->fields.size;
  unsigned nMatches = 0;
  bool formatNotChanged = (nFields == this->nFields);

  for (dbFieldDescriptor* fd = firstField; fd != NULL; fd = fd->nextField)
  {
    dbField* field = (dbField*)((char*)table + table->fields.offs);
    fd->oldDbsType = dbField::tpUnknown;

    for (int n = nFields; --n >= 0; field++)
    {
      if (strcmp(fd->longName, (char*)field + field->name.offs) == 0)
      {
        assert(((void)"field can be converted to new format",
                (fd->type == dbField::tpReference
                 && field->type == dbField::tpReference
                 && strcmp((char*)field + field->tableName.offs,
                           fd->refTable->name) == 0)
                || (fd->type <= dbField::tpReal8
                    && field->type <= dbField::tpReal8)
                || (fd->type == dbField::tpString
                    && field->type == dbField::tpString)
                || (fd->type >= dbField::tpArray
                    && fd->type == field->type)));
        fd->oldDbsType = field->type;
        fd->oldDbsOffs = field->offset;
        fd->oldDbsSize = field->size;

        if (field->type != fd->type || field->offset != fd->dbsOffs)
        {
          formatNotChanged = false;
        }

        nMatches += 1;
        //
        // Try to reuse indices
        //
        fd->hashTable = 0;
        fd->tTree = 0;

        if (field->type == fd->type)
        {
          if ((fd->indexType & HASHED) != 0 && field->hashTable != 0)
          {
            fd->hashTable = field->hashTable; // reuse index
            field->hashTable = 0; // prevent index from destruction
          }

          if ((fd->indexType & INDEXED) != 0 && field->tTree != 0)
          {
            fd->tTree = field->tTree; // reuse index
            field->tTree = 0; // prevent index from destruction
          }
        }

        break;
      }
    }
  }

  if (!confirmDeleteColumns)
  {
    assert(((void)"field can be removed only from empty table",
            nFields==nMatches));
  }

  return formatNotChanged;
}

void dbTableDescriptor::setFlags()
{
  for (dbFieldDescriptor* fd = firstField; fd != NULL; fd = fd->nextField)
  {
    if (fd->tTree != 0)
    {
      fd->indexType |= INDEXED;
    }
    else if (fd->hashTable != 0)
    {
      fd->indexType |= HASHED;
    }
  }
}


bool dbTableDescriptor::equal(dbTable* table)
{
#ifdef AUTOINCREMENT_SUPPORT
  autoincrementCount = table->count;
#endif

  if (nColumns != table->nColumns ||
      nFields != table->fields.size || fixedSize != table->fixedSize)
  {
    return false;
  }

  dbField* field = (dbField*)((char*)table + table->fields.offs);

  for (dbFieldDescriptor* fd = firstField; fd != NULL; fd = fd->nextField)
  {
    if (strcmp(fd->longName, (char*)field + field->name.offs) != 0
        || (!fd->refTable && *((char*)field+field->tableName.offs) != '\0')
        || (fd->refTable && strcmp((char*)field + field->tableName.offs,
                                   fd->refTable->name) != 0)
        || (fd->inverseRefName == NULL
            && *((char*)field + field->inverse.offs) != '\0')
        || (fd->inverseRefName != NULL
            && strcmp((char*)field + field->inverse.offs,
                      fd->inverseRefName) != 0)
        || fd->dbsOffs != field->offset
        || fd->type != field->type)
    {
      return false;
    }

    fd->tTree = field->tTree;
    fd->hashTable = field->hashTable;
    field += 1;
  }

  return true;
}


dbTableDescriptor::dbTableDescriptor(dbTable* table)
{
  next = chain;
  chain = this;
  cloneOf = NULL;
  isStatic = false;
  name = (char*)table + table->name.offs;

  dbSymbolTable::add
    (name, tkn_ident, true);

  nextFieldLink = &firstField;

  hashedFields = NULL;

  indexedFields = NULL;

  inverseFields = NULL;

  nFields = 0;

  nColumns = 0;

  fixedSize = table->fixedSize;