github.com/juju/juju@v0.0.0-20240430160146-1752b71fcf00/core/quota/bson.go (about)

     1  // Copyright 2020 Canonical Ltd.
     2  // Licensed under the AGPLv3, see LICENCE file for details.
     3  
     4  package quota
     5  
     6  import (
     7  	"github.com/juju/errors"
     8  )
     9  
    10  var _ Checker = (*BSONTotalSizeChecker)(nil)
    11  
    12  // BSONTotalSizeChecker can be used to verify that the total bson-encoded size
    13  // of one or more items does not exceed a particular limit.
    14  type BSONTotalSizeChecker struct {
    15  	maxSize int
    16  	total   int
    17  	lastErr error
    18  }
    19  
    20  // NewBSONTotalSizeChecker returns a BSONTotalSizeChecker instance with the
    21  // specified maxSize limit. The maxSize parameter may also be set to zero to
    22  // disable quota checks.
    23  func NewBSONTotalSizeChecker(maxSize int) *BSONTotalSizeChecker {
    24  	return &BSONTotalSizeChecker{
    25  		maxSize: maxSize,
    26  	}
    27  }
    28  
    29  // Check adds the serialized size of v to the current tally and updates the
    30  // checker's error state.
    31  func (c *BSONTotalSizeChecker) Check(v interface{}) {
    32  	if c.lastErr != nil {
    33  		return
    34  	}
    35  
    36  	size, err := effectiveSize(v)
    37  	if err != nil {
    38  		c.lastErr = err
    39  		return
    40  	} else if c.maxSize > 0 && c.total+size > c.maxSize {
    41  		c.lastErr = errors.QuotaLimitExceededf("max allowed size (%d) exceeded", c.maxSize)
    42  	}
    43  
    44  	c.total += size
    45  }
    46  
    47  // Outcome returns the check outcome or whether an error occurred within a call
    48  // to the Check method.
    49  func (c *BSONTotalSizeChecker) Outcome() error {
    50  	return c.lastErr
    51  }