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-rw-r--r--models/db/list.go215
1 files changed, 215 insertions, 0 deletions
diff --git a/models/db/list.go b/models/db/list.go
new file mode 100644
index 0000000..5c005a0
--- /dev/null
+++ b/models/db/list.go
@@ -0,0 +1,215 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package db
+
+import (
+ "context"
+
+ "code.gitea.io/gitea/modules/setting"
+
+ "xorm.io/builder"
+ "xorm.io/xorm"
+)
+
+const (
+ // DefaultMaxInSize represents default variables number on IN () in SQL
+ DefaultMaxInSize = 50
+ defaultFindSliceSize = 10
+)
+
+// Paginator is the base for different ListOptions types
+type Paginator interface {
+ GetSkipTake() (skip, take int)
+ IsListAll() bool
+}
+
+// SetSessionPagination sets pagination for a database session
+func SetSessionPagination(sess Engine, p Paginator) *xorm.Session {
+ skip, take := p.GetSkipTake()
+
+ return sess.Limit(take, skip)
+}
+
+// ListOptions options to paginate results
+type ListOptions struct {
+ PageSize int
+ Page int // start from 1
+ ListAll bool // if true, then PageSize and Page will not be taken
+}
+
+var ListOptionsAll = ListOptions{ListAll: true}
+
+var (
+ _ Paginator = &ListOptions{}
+ _ FindOptions = ListOptions{}
+)
+
+// GetSkipTake returns the skip and take values
+func (opts *ListOptions) GetSkipTake() (skip, take int) {
+ opts.SetDefaultValues()
+ return (opts.Page - 1) * opts.PageSize, opts.PageSize
+}
+
+func (opts ListOptions) GetPage() int {
+ return opts.Page
+}
+
+func (opts ListOptions) GetPageSize() int {
+ return opts.PageSize
+}
+
+// IsListAll indicates PageSize and Page will be ignored
+func (opts ListOptions) IsListAll() bool {
+ return opts.ListAll
+}
+
+// SetDefaultValues sets default values
+func (opts *ListOptions) SetDefaultValues() {
+ if opts.PageSize <= 0 {
+ opts.PageSize = setting.API.DefaultPagingNum
+ }
+ if opts.PageSize > setting.API.MaxResponseItems {
+ opts.PageSize = setting.API.MaxResponseItems
+ }
+ if opts.Page <= 0 {
+ opts.Page = 1
+ }
+}
+
+func (opts ListOptions) ToConds() builder.Cond {
+ return builder.NewCond()
+}
+
+// AbsoluteListOptions absolute options to paginate results
+type AbsoluteListOptions struct {
+ skip int
+ take int
+}
+
+var _ Paginator = &AbsoluteListOptions{}
+
+// NewAbsoluteListOptions creates a list option with applied limits
+func NewAbsoluteListOptions(skip, take int) *AbsoluteListOptions {
+ if skip < 0 {
+ skip = 0
+ }
+ if take <= 0 {
+ take = setting.API.DefaultPagingNum
+ }
+ if take > setting.API.MaxResponseItems {
+ take = setting.API.MaxResponseItems
+ }
+ return &AbsoluteListOptions{skip, take}
+}
+
+// IsListAll will always return false
+func (opts *AbsoluteListOptions) IsListAll() bool {
+ return false
+}
+
+// GetSkipTake returns the skip and take values
+func (opts *AbsoluteListOptions) GetSkipTake() (skip, take int) {
+ return opts.skip, opts.take
+}
+
+// FindOptions represents a find options
+type FindOptions interface {
+ GetPage() int
+ GetPageSize() int
+ IsListAll() bool
+ ToConds() builder.Cond
+}
+
+type JoinFunc func(sess Engine) error
+
+type FindOptionsJoin interface {
+ ToJoins() []JoinFunc
+}
+
+type FindOptionsOrder interface {
+ ToOrders() string
+}
+
+// Find represents a common find function which accept an options interface
+func Find[T any](ctx context.Context, opts FindOptions) ([]*T, error) {
+ sess := GetEngine(ctx).Where(opts.ToConds())
+
+ if joinOpt, ok := opts.(FindOptionsJoin); ok {
+ for _, joinFunc := range joinOpt.ToJoins() {
+ if err := joinFunc(sess); err != nil {
+ return nil, err
+ }
+ }
+ }
+ if orderOpt, ok := opts.(FindOptionsOrder); ok {
+ if order := orderOpt.ToOrders(); order != "" {
+ sess.OrderBy(order)
+ }
+ }
+
+ page, pageSize := opts.GetPage(), opts.GetPageSize()
+ if !opts.IsListAll() && pageSize > 0 {
+ if page == 0 {
+ page = 1
+ }
+ sess.Limit(pageSize, (page-1)*pageSize)
+ }
+
+ findPageSize := defaultFindSliceSize
+ if pageSize > 0 {
+ findPageSize = pageSize
+ }
+ objects := make([]*T, 0, findPageSize)
+ if err := sess.Find(&objects); err != nil {
+ return nil, err
+ }
+ return objects, nil
+}
+
+// Count represents a common count function which accept an options interface
+func Count[T any](ctx context.Context, opts FindOptions) (int64, error) {
+ sess := GetEngine(ctx).Where(opts.ToConds())
+ if joinOpt, ok := opts.(FindOptionsJoin); ok {
+ for _, joinFunc := range joinOpt.ToJoins() {
+ if err := joinFunc(sess); err != nil {
+ return 0, err
+ }
+ }
+ }
+
+ var object T
+ return sess.Count(&object)
+}
+
+// FindAndCount represents a common findandcount function which accept an options interface
+func FindAndCount[T any](ctx context.Context, opts FindOptions) ([]*T, int64, error) {
+ sess := GetEngine(ctx).Where(opts.ToConds())
+ page, pageSize := opts.GetPage(), opts.GetPageSize()
+ if !opts.IsListAll() && pageSize > 0 && page >= 1 {
+ sess.Limit(pageSize, (page-1)*pageSize)
+ }
+ if joinOpt, ok := opts.(FindOptionsJoin); ok {
+ for _, joinFunc := range joinOpt.ToJoins() {
+ if err := joinFunc(sess); err != nil {
+ return nil, 0, err
+ }
+ }
+ }
+ if orderOpt, ok := opts.(FindOptionsOrder); ok {
+ if order := orderOpt.ToOrders(); order != "" {
+ sess.OrderBy(order)
+ }
+ }
+
+ findPageSize := defaultFindSliceSize
+ if pageSize > 0 {
+ findPageSize = pageSize
+ }
+ objects := make([]*T, 0, findPageSize)
+ cnt, err := sess.FindAndCount(&objects)
+ if err != nil {
+ return nil, 0, err
+ }
+ return objects, cnt, nil
+}