122 lines
4.7 KiB
Go
122 lines
4.7 KiB
Go
// Copyright 2024 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 ast
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import (
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"fmt"
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"regexp"
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"github.com/cockroachdb/errors"
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vitess "github.com/dolthub/vitess/go/vt/sqlparser"
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"github.com/dolthub/doltgresql/core/id"
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"github.com/dolthub/doltgresql/core/triggers"
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"github.com/dolthub/doltgresql/postgres/parser/sem/tree"
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pgnodes "github.com/dolthub/doltgresql/server/node"
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"github.com/dolthub/doltgresql/server/plpgsql"
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)
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// createTriggerWhenCapture is a regex that should only capture the contents of the WHEN expression. Although a bit
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// complex, this is done to ensure that the capture group contains only the WHEN expression and nothing else.
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var createTriggerWhenCapture = regexp.MustCompile(`(?is)create\s+(?:or\s+replace\s+)?(?:constraint\s+)?trigger\s+.*\s+for\s+(?:each\s+)?(?:row|statement)\s+when\s+\((.*)\)\s+execute\s+(?:function|procedure).*`)
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// nodeCreateTrigger handles *tree.CreateTrigger nodes.
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func nodeCreateTrigger(ctx *Context, node *tree.CreateTrigger) (_ vitess.Statement, err error) {
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if node.Constraint {
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return NotYetSupportedError("CREATE CONSTRAINT TRIGGER is not yet supported")
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}
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if !node.RefTable.IsEmpty() {
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return NotYetSupportedError("FROM is not yet supported for CREATE TRIGGER")
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}
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if node.Deferrable != tree.TriggerNotDeferrable {
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return NotYetSupportedError("DEFERRABLE is not yet supported for CREATE TRIGGER")
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}
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if len(node.Relations) > 0 {
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return NotYetSupportedError("REFERENCING is not yet supported for CREATE TRIGGER")
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}
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if !node.ForEachRow {
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return NotYetSupportedError("FOR EACH STATEMENT is not yet supported for CREATE TRIGGER")
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}
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funcName := node.FuncName.ToTableName()
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var timing triggers.TriggerTiming
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switch node.Time {
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case tree.TriggerTimeBefore:
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timing = triggers.TriggerTiming_Before
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case tree.TriggerTimeAfter:
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timing = triggers.TriggerTiming_After
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case tree.TriggerTimeInsteadOf:
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return NotYetSupportedError("INSTEAD OF is not yet supported for CREATE TRIGGER")
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}
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var events []triggers.TriggerEvent
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for _, event := range node.Events {
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switch event.Type {
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case tree.TriggerEventInsert:
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events = append(events, triggers.TriggerEvent{
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Type: triggers.TriggerEventType_Insert,
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})
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case tree.TriggerEventUpdate:
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if len(event.Cols) > 0 {
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return NotYetSupportedError("UPDATE specific columns are not yet supported for CREATE TRIGGER")
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}
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events = append(events, triggers.TriggerEvent{
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Type: triggers.TriggerEventType_Update,
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ColumnNames: event.Cols.ToStrings(),
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})
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case tree.TriggerEventDelete:
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events = append(events, triggers.TriggerEvent{
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Type: triggers.TriggerEventType_Delete,
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})
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case tree.TriggerEventTruncate:
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return NotYetSupportedError("TRUNCATE is not yet supported for CREATE TRIGGER")
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default:
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return NotYetSupportedError("UNKNOWN EVENT TYPE is not yet supported for CREATE TRIGGER")
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}
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}
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// WHEN expressions seem to behave identically to interpreted functions, so we'll parse them as interpreted functions.
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// To do this, we need the raw string, and we wrap it as though it were a trigger function (which has special logic
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// for handling NEW and OLD rows). Using a regex for this rather than modifying the parser may seem suboptimal, but
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// we want to retain the parser validation of using an expression, however we cannot rely on the expression's
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// String() function to return the **exact** same string, so we capture it with a regex.
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var whenOps []plpgsql.InterpreterOperation
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if node.When != nil {
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matches := createTriggerWhenCapture.FindStringSubmatch(ctx.originalQuery)
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if len(matches) != 2 {
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return nil, errors.New("unable to parse WHEN expression from CREATE TRIGGER")
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}
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whenOps, err = plpgsql.Parse(fmt.Sprintf(`CREATE FUNCTION when_wrapper() RETURNS TRIGGER AS $$
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BEGIN
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RETURN %s;
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END;
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$$ LANGUAGE plpgsql;`, matches[1]))
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if err != nil {
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return nil, err
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}
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}
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return vitess.InjectedStatement{
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Statement: pgnodes.NewCreateTrigger(
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id.NewTrigger(node.OnTable.Schema(), node.OnTable.Table(), node.Name.String()),
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id.NewFunction(funcName.Schema(), funcName.Table()),
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node.Replace,
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timing,
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events,
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node.ForEachRow,
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whenOps,
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node.Args.ToStrings(),
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ctx.originalQuery,
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),
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Children: nil,
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}, nil
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}
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