Release v0.1.0

vendor/github.com/btcsuite/btcd/database/error.go

@@ -0,0 +1,197 @@
+// 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}
+}