wehub-resource-sync
104 lines
4.3 KiB
Go
104 lines
4.3 KiB
Go
// Copyright 2025 Dolthub, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package id
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import "github.com/dolthub/go-mysql-server/sql"
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// Operation represents an operation that is being performed or validated.
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type Operation uint8
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const (
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Operation_Rename Operation = iota
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Operation_Delete
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Operation_Delete_Cascade
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)
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// registry is the implementation of the global registry. This holds all functions that operate or validate a change on
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// an ID.
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type registry struct {
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listeners [][]Listener
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}
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// globalRegistry is the variable that is referenced for the registry.
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var globalRegistry = ®istry{
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listeners: make([][]Listener, section_count),
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}
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type Listener interface {
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// OperationPerformer is a function that performs the given operation on the original ID. Some operations, such as
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// renames, will use the new ID.
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OperationPerformer(ctx *sql.Context, operation Operation, databaseName string, originalID Id, newID Id) error
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// OperationValidator is a function that validates the given operation on the original ID. Some operations, such as
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// renames, will use the new ID. A validator is not required, and is intended for operations that may be relatively
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// expensive to perform, but able to check quickly for failures. In addition, validators should not perform any
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// modifications. If a validator is not required, then this should just return nil.
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OperationValidator(ctx *sql.Context, operation Operation, databaseName string, originalID Id, newID Id) error
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}
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// RegisterListener registers the given listener for the given sections.
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//
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// For example, sequences are related to tables. Whenever a table operation is performed that changes its ID, sequences
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// will also need to update their IDs that reference the table. This is accomplished by registering a performer that
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// accepts a table section, where the performer modifies sequences as needed.
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//
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// Performers should not register sections that are directly related to themselves. For example, a sequence performer
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// should not register itself under the sequence section, as it will be the one broadcasting that section, and therefore
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// could cause a loop.
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func RegisterListener(listener Listener, sections ...Section) {
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for _, section := range sections {
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if section == Section_Null {
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continue
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}
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globalRegistry.listeners[section] = append(globalRegistry.listeners[section], listener)
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}
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}
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// PerformOperation calls all registered performers that are associated with the given section. This does not call any
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// validators, which should be done using ValidateOperation. This returns the first error that is encountered.
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func PerformOperation(ctx *sql.Context, targetSection Section, operation Operation, databaseName string, originalID Id, newID Id) error {
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for _, listener := range globalRegistry.listeners[targetSection] {
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if err := listener.OperationPerformer(ctx, operation, databaseName, originalID, newID); err != nil {
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return err
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}
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}
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// TODO: need to look for tables that store OIDs in their columns and UPDATE them to the new value
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// it will be relatively slow, but that's the price a user pays to store OIDs in their tables
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return nil
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}
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// ValidateOperation calls all registered validators that are associated with the given section.
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func ValidateOperation(ctx *sql.Context, targetSection Section, operation Operation, databaseName string, originalID Id, newID Id) error {
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for _, listener := range globalRegistry.listeners[targetSection] {
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if err := listener.OperationValidator(ctx, operation, databaseName, originalID, newID); err != nil {
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return err
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}
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}
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return nil
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}
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// String returns the name of the operation.
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func (op Operation) String() string {
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switch op {
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case Operation_Rename:
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return "Rename"
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case Operation_Delete:
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return "Delete"
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case Operation_Delete_Cascade:
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return "DeleteCascade"
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default:
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return "UNKNOWN_OPERATION"
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}
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}
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