Add dbutil for building mass insert queries

dbutil/massinsert.go

@@ -0,0 +1,91 @@
+// Copyright (c) 2024 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package dbutil
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+type Array interface {
+	[1]any | [2]any | [3]any | [4]any | [5]any | [6]any | [7]any | [8]any | [9]any | [10]any | [11]any | [12]any | [13]any | [14]any | [15]any | [16]any | [17]any | [18]any | [19]any | [20]any
+}
+
+type MassInsertable[T Array] interface {
+	GetMassInsertValues() T
+}
+
+type MassInsertBuilder[Item MassInsertable[DynamicParams], StaticParams Array, DynamicParams Array] struct {
+	queryTemplate       string
+	placeholderTemplate string
+}
+
+func NewMassInsertBuilder[Item MassInsertable[DynamicParams], StaticParams Array, DynamicParams Array](
+	singleInsertQuery, placeholderTemplate string,
+) *MassInsertBuilder[Item, StaticParams, DynamicParams] {
+	var dyn DynamicParams
+	var stat StaticParams
+	totalParams := len(dyn) + len(stat)
+	mainQueryVariablePlaceholderParts := make([]string, totalParams)
+	for i := 0; i < totalParams; i++ {
+		mainQueryVariablePlaceholderParts[i] = fmt.Sprintf(`\$%d`, i+1)
+	}
+	mainQueryVariablePlaceholderRegex := regexp.MustCompile(fmt.Sprintf(`\(\s*%s\s*\)`, strings.Join(mainQueryVariablePlaceholderParts, `\s*,\s*`)))
+	queryPlaceholders := mainQueryVariablePlaceholderRegex.FindAllString(singleInsertQuery, -1)
+	if len(queryPlaceholders) == 0 {
+		panic(fmt.Errorf("invalid insert query: placeholders not found"))
+	} else if len(queryPlaceholders) > 1 {
+		panic(fmt.Errorf("invalid insert query: multiple placeholders found"))
+	}
+	for i := 0; i < len(stat); i++ {
+		if !strings.Contains(placeholderTemplate, fmt.Sprintf("$%d", i+1)) {
+			panic(fmt.Errorf("invalid placeholder template: static placeholder $%d not found", i+1))
+		}
+	}
+	if strings.Contains(placeholderTemplate, fmt.Sprintf("$%d", len(stat)+1)) {
+		panic(fmt.Errorf("invalid placeholder template: non-static placeholder $%d found", len(stat)+1))
+	}
+	fmtParams := make([]any, len(dyn))
+	for i := 0; i < len(dyn); i++ {
+		fmtParams[i] = fmt.Sprintf("$%d", len(stat)+i+1)
+	}
+	formattedPlaceholder := fmt.Sprintf(placeholderTemplate, fmtParams...)
+	if strings.Contains(formattedPlaceholder, "!(EXTRA string=") {
+		panic(fmt.Errorf("invalid placeholder template: extra string found"))
+	}
+	for i := 0; i < len(dyn); i++ {
+		if !strings.Contains(formattedPlaceholder, fmt.Sprintf("$%d", len(stat)+i+1)) {
+			panic(fmt.Errorf("invalid placeholder template: dynamic placeholder $%d not found", len(stat)+i+1))
+		}
+	}
+	return &MassInsertBuilder[Item, StaticParams, DynamicParams]{
+		queryTemplate:       strings.Replace(singleInsertQuery, queryPlaceholders[0], "%s", 1),
+		placeholderTemplate: placeholderTemplate,
+	}
+}
+
+func (mib *MassInsertBuilder[Item, StaticParams, DynamicParams]) Build(static StaticParams, data []Item) (query string, params []any) {
+	var itemValues DynamicParams
+	params = make([]any, len(static)+len(itemValues)*len(data))
+	placeholders := make([]string, len(data))
+	for i := 0; i < len(static); i++ {
+		params[i] = static[i]
+	}
+	fmtParams := make([]any, len(itemValues))
+	for i, item := range data {
+		baseIndex := len(static) + len(itemValues)*i
+		itemValues = item.GetMassInsertValues()
+		for j := 0; j < len(itemValues); j++ {
+			params[baseIndex+j] = itemValues[j]
+			fmtParams[j] = baseIndex + j + 1
+		}
+		placeholders[i] = fmt.Sprintf(mib.placeholderTemplate, fmtParams...)
+	}
+	query = fmt.Sprintf(mib.queryTemplate, strings.Join(placeholders, ", "))
+	return
+}

dbutil/massinsert_test.go

@@ -0,0 +1,47 @@
+// Copyright (c) 2024 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package dbutil_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"go.mau.fi/util/dbutil"
+)
+
+type AbstractMassInsertable[T dbutil.Array] struct {
+	Data T
+}
+
+func (a AbstractMassInsertable[T]) GetMassInsertValues() T {
+	return a.Data
+}
+
+type OneParamMassInsertable = AbstractMassInsertable[[1]any]
+
+func TestNewMassInsertBuilder_InvalidParams(t *testing.T) {
+	assert.PanicsWithError(t, "invalid insert query: placeholders not found", func() {
+		dbutil.NewMassInsertBuilder[OneParamMassInsertable, [1]any]("", "")
+	})
+	assert.PanicsWithError(t, "invalid placeholder template: static placeholder $1 not found", func() {
+		dbutil.NewMassInsertBuilder[OneParamMassInsertable, [1]any]("INSERT INTO foo VALUES ($1, $2)", "")
+	})
+	assert.PanicsWithError(t, "invalid placeholder template: non-static placeholder $2 found", func() {
+		dbutil.NewMassInsertBuilder[OneParamMassInsertable, [1]any]("INSERT INTO foo VALUES ($1, $2)", "($1, $2)")
+	})
+	assert.PanicsWithError(t, "invalid placeholder template: extra string found", func() {
+		dbutil.NewMassInsertBuilder[OneParamMassInsertable, [1]any]("INSERT INTO foo VALUES ($1, $2)", "($1)")
+	})
+}
+
+func TestMassInsertBuilder_Build(t *testing.T) {
+	builder := dbutil.NewMassInsertBuilder[OneParamMassInsertable, [1]any]("INSERT INTO foo VALUES ($1, $2)", "($1, $%d)")
+	query, values := builder.Build([1]any{"hi"}, []OneParamMassInsertable{{[1]any{"hmm"}}, {[1]any{"meow"}}, {[1]any{"third"}}})
+	assert.Equal(t, "INSERT INTO foo VALUES ($1, $2), ($1, $3), ($1, $4)", query)
+	assert.Equal(t, []any{"hi", "hmm", "meow", "third"}, values)
+}

exslices/chunk.go

@@ -0,0 +1,28 @@
+// Copyright (c) 2024 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package exslices
+
+// Chunk splits a slice into chunks of the given size.
+//
+// From https://github.com/golang/go/issues/53987#issuecomment-1224367139
+//
+// TODO remove this after slices.Chunk can be used (it'll probably be added in Go 1.23, so it can be used after 1.22 is EOL)
+func Chunk[T any](slice []T, size int) (chunks [][]T) {
+	if size < 1 {
+		panic("chunk size cannot be less than 1")
+	}
+	for i := 0; ; i++ {
+		next := i * size
+		if len(slice[next:]) > size {
+			end := next + size
+			chunks = append(chunks, slice[next:end:end])
+		} else {
+			chunks = append(chunks, slice[i*size:])
+			return
+		}
+	}
+}