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dolt/go/libraries/doltcore/diff/diff.go
2024-05-02 16:09:34 -07:00

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// Copyright 2022 Dolthub, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package diff
import (
"context"
"time"
"github.com/dolthub/go-mysql-server/sql"
"github.com/dolthub/dolt/go/store/diff"
"github.com/dolthub/dolt/go/store/types"
)
// ChangeType is an enum that represents the type of change in a diff
type ChangeType int
const (
// None is no change
None ChangeType = iota
// Added is the ChangeType value for a row that was newly added (In new, but not in old)
Added
// Removed is the ChangeTypeProp value for a row that was newly deleted (In old, but not in new)
Removed
// ModifiedOld is the ChangeType value for the row which represents the old value of the row before it was changed.
ModifiedOld
// ModifiedNew is the ChangeType value for the row which represents the new value of the row after it was changed.
ModifiedNew
)
// Mode is an enum that represents the presentation of a diff
type Mode int
const (
ModeRow Mode = 0
ModeLine Mode = 1
ModeInPlace Mode = 2
ModeContext Mode = 3
)
type RowDiffer interface {
// Start starts the RowDiffer.
Start(ctx context.Context, from, to types.Map)
// StartWithRange starts the RowDiffer with the specified range
StartWithRange(ctx context.Context, from, to types.Map, start types.Value, inRange types.ValueInRange)
// GetDiffs returns the requested number of diff.Differences, or times out.
GetDiffs(numDiffs int, timeout time.Duration) ([]*diff.Difference, bool, error)
// GetDiffsWithFilter returns the requested number of filtered diff.Differences, or times out.
GetDiffsWithFilter(numDiffs int, timeout time.Duration, filterByChangeType types.DiffChangeType) ([]*diff.Difference, bool, error)
// Close closes the RowDiffer.
Close() error
}
// SqlRowDiffWriter knows how to write diff rows for a table to an arbitrary format and destination.
type SqlRowDiffWriter interface {
// WriteRow writes the diff row given, of the diff type provided. colDiffTypes is guaranteed to be the same length as
// the input row.
WriteRow(ctx context.Context, row sql.Row, diffType ChangeType, colDiffTypes []ChangeType) error
// WriteCombinedRow writes the diff of the rows given as a single, combined row.
WriteCombinedRow(ctx context.Context, oldRow, newRow sql.Row, mode Mode) error
// Close finalizes the work of this writer.
Close(ctx context.Context) error
}
// SchemaDiffWriter knows how to write SQL DDL statements for a schema diff for a table to an arbitrary format and
// destination.
type SchemaDiffWriter interface {
// WriteSchemaDiff writes the schema diff given (a SQL statement) and returns any error. A single table may have
// many SQL statements for a single diff. WriteSchemaDiff will be called before any row diffs via |WriteRow|
WriteSchemaDiff(schemaDiffStatement string) error
// Close finalizes the work of this writer.
Close() error
}