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error.go
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error.go
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// Copyright (c) 2015-2016 The btcsuite developers
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package database
import "fmt"
// ErrorCode identifies a kind of error.
type ErrorCode int
// These constants are used to identify a specific database Error.
const (
// **************************************
// Errors related to driver registration.
// **************************************
// ErrDbTypeRegistered indicates two different database drivers
// attempt to register with the name database type.
ErrDbTypeRegistered ErrorCode = iota
// *************************************
// Errors related to database functions.
// *************************************
// ErrDbUnknownType indicates there is no driver registered for
// the specified database type.
ErrDbUnknownType
// ErrDbDoesNotExist indicates open is called for a database that
// does not exist.
ErrDbDoesNotExist
// ErrDbExists indicates create is called for a database that
// already exists.
ErrDbExists
// ErrDbNotOpen indicates a database instance is accessed before
// it is opened or after it is closed.
ErrDbNotOpen
// ErrDbAlreadyOpen indicates open was called on a database that
// is already open.
ErrDbAlreadyOpen
// ErrInvalid indicates the specified database is not valid.
ErrInvalid
// ErrCorruption indicates a checksum failure occurred which invariably
// means the database is corrupt.
ErrCorruption
// ****************************************
// Errors related to database transactions.
// ****************************************
// ErrTxClosed indicates an attempt was made to commit or rollback a
// transaction that has already had one of those operations performed.
ErrTxClosed
// ErrTxNotWritable indicates an operation that requires write access to
// the database was attempted against a read-only transaction.
ErrTxNotWritable
// **************************************
// Errors related to metadata operations.
// **************************************
// ErrBucketNotFound indicates an attempt to access a bucket that has
// not been created yet.
ErrBucketNotFound
// ErrBucketExists indicates an attempt to create a bucket that already
// exists.
ErrBucketExists
// ErrBucketNameRequired indicates an attempt to create a bucket with a
// blank name.
ErrBucketNameRequired
// ErrKeyRequired indicates at attempt to insert a zero-length key.
ErrKeyRequired
// ErrKeyTooLarge indicates an attmempt to insert a key that is larger
// than the max allowed key size. The max key size depends on the
// specific backend driver being used. As a general rule, key sizes
// should be relatively, so this should rarely be an issue.
ErrKeyTooLarge
// ErrValueTooLarge indicates an attmpt to insert a value that is larger
// than max allowed value size. The max key size depends on the
// specific backend driver being used.
ErrValueTooLarge
// ErrIncompatibleValue indicates the value in question is invalid for
// the specific requested operation. For example, trying create or
// delete a bucket with an existing non-bucket key, attempting to create
// or delete a non-bucket key with an existing bucket key, or trying to
// delete a value via a cursor when it points to a nested bucket.
ErrIncompatibleValue
// ***************************************
// Errors related to block I/O operations.
// ***************************************
// ErrBlockNotFound indicates a block with the provided hash does not
// exist in the database.
ErrBlockNotFound
// ErrBlockExists indicates a block with the provided hash already
// exists in the database.
ErrBlockExists
// ErrBlockRegionInvalid indicates a region that exceeds the bounds of
// the specified block was requested. When the hash provided by the
// region does not correspond to an existing block, the error will be
// ErrBlockNotFound instead.
ErrBlockRegionInvalid
// ***********************************
// Support for driver-specific errors.
// ***********************************
// ErrDriverSpecific indicates the Err field is a driver-specific error.
// This provides a mechanism for drivers to plug-in their own custom
// errors for any situations which aren't already covered by the error
// codes provided by this package.
ErrDriverSpecific
// numErrorCodes is the maximum error code number used in tests.
numErrorCodes
)
// Map of ErrorCode values back to their constant names for pretty printing.
var errorCodeStrings = map[ErrorCode]string{
ErrDbTypeRegistered: "ErrDbTypeRegistered",
ErrDbUnknownType: "ErrDbUnknownType",
ErrDbDoesNotExist: "ErrDbDoesNotExist",
ErrDbExists: "ErrDbExists",
ErrDbNotOpen: "ErrDbNotOpen",
ErrDbAlreadyOpen: "ErrDbAlreadyOpen",
ErrInvalid: "ErrInvalid",
ErrCorruption: "ErrCorruption",
ErrTxClosed: "ErrTxClosed",
ErrTxNotWritable: "ErrTxNotWritable",
ErrBucketNotFound: "ErrBucketNotFound",
ErrBucketExists: "ErrBucketExists",
ErrBucketNameRequired: "ErrBucketNameRequired",
ErrKeyRequired: "ErrKeyRequired",
ErrKeyTooLarge: "ErrKeyTooLarge",
ErrValueTooLarge: "ErrValueTooLarge",
ErrIncompatibleValue: "ErrIncompatibleValue",
ErrBlockNotFound: "ErrBlockNotFound",
ErrBlockExists: "ErrBlockExists",
ErrBlockRegionInvalid: "ErrBlockRegionInvalid",
ErrDriverSpecific: "ErrDriverSpecific",
}
// String returns the ErrorCode as a human-readable name.
func (e ErrorCode) String() string {
if s := errorCodeStrings[e]; s != "" {
return s
}
return fmt.Sprintf("Unknown ErrorCode (%d)", int(e))
}
// Error provides a single type for errors that can happen during database
// operation. It is used to indicate several types of failures including errors
// with caller requests such as specifying invalid block regions or attempting
// to access data against closed database transactions, driver errors, errors
// retrieving data, and errors communicating with database servers.
//
// The caller can use type assertions to determine if an error is an Error and
// access the ErrorCode field to ascertain the specific reason for the failure.
//
// The ErrDriverSpecific error code will also have the Err field set with the
// underlying error. Depending on the backend driver, the Err field might be
// set to the underlying error for other error codes as well.
type Error struct {
ErrorCode ErrorCode // Describes the kind of error
Description string // Human readable description of the issue
Err error // Underlying error
}
// Error satisfies the error interface and prints human-readable errors.
func (e Error) Error() string {
if e.Err != nil {
return e.Description + ": " + e.Err.Error()
}
return e.Description
}
// makeError creates an Error given a set of arguments. The error code must
// be one of the error codes provided by this package.
func makeError(c ErrorCode, desc string, err error) Error {
return Error{ErrorCode: c, Description: desc, Err: err}
}