82 lines
3.0 KiB
Go
82 lines
3.0 KiB
Go
// Package ormlist defines options for listing items from ORM indexes.
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package ormlist
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import (
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"google.golang.org/protobuf/proto"
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queryv1beta1 "cosmossdk.io/api/cosmos/base/query/v1beta1"
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"cosmossdk.io/orm/internal/listinternal"
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)
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// Option represents a list option.
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type Option = listinternal.Option
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// Reverse reverses the direction of iteration. If Reverse is
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// provided twice, iteration will happen in the forward direction.
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func Reverse() Option {
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return listinternal.FuncOption(func(options *listinternal.Options) {
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options.Reverse = !options.Reverse
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})
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}
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// Filter returns an option which applies a filter function to each item
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// and skips over it when the filter function returns false.
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func Filter(filterFn func(message proto.Message) bool) Option {
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return listinternal.FuncOption(func(options *listinternal.Options) {
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options.Filter = filterFn
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})
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}
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// Cursor specifies a cursor after which to restart iteration. Cursor values
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// are returned by iterators and in pagination results.
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func Cursor(cursor CursorT) Option {
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return listinternal.FuncOption(func(options *listinternal.Options) {
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options.Cursor = cursor
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})
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}
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// Paginate paginates iterator output based on the provided page request.
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// The Iterator.PageRequest value on the returned iterator will be non-nil
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// after Iterator.Next() returns false when this option is provided.
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//
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// Care should be taken when using Paginate together with Reverse and/or Cursor.
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// In the case of combining Reverse and Paginate, if pageRequest.Reverse is
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// true then iteration will proceed in the forward direction. This allows
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// the default iteration direction for a query to be reverse with the option
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// to switch this (to forward in this case) using PageRequest. If Cursor
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// and Paginate are used together, whichever option is used first wins.
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// If pageRequest is nil, this option will be a no-op so the caller does not
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// need to do a nil check. This function defines no default limit, so if
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// the caller does not define a limit, this will return all results. To
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// specify a default limit use the DefaultLimit option.
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func Paginate(pageRequest *queryv1beta1.PageRequest) Option {
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return listinternal.FuncOption(func(options *listinternal.Options) {
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if pageRequest == nil {
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return
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}
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if pageRequest.Reverse {
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// if the reverse is true we invert the direction of iteration,
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// meaning if iteration was already reversed we set it forward.
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options.Reverse = !options.Reverse
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}
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options.Cursor = pageRequest.Key
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options.Offset = pageRequest.Offset
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options.Limit = pageRequest.Limit
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options.CountTotal = pageRequest.CountTotal
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})
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}
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// DefaultLimit specifies a default limit for iteration. This option can be
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// combined with Paginate to ensure that there is a default limit if none
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// is specified in PageRequest.
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func DefaultLimit(defaultLimit uint64) Option {
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return listinternal.FuncOption(func(options *listinternal.Options) {
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options.DefaultLimit = defaultLimit
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})
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}
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// CursorT defines a cursor type.
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type CursorT []byte
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