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https://github.com/MichaelMure/git-bug.git
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123 lines
3.1 KiB
Go
123 lines
3.1 KiB
Go
package connections
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import (
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"fmt"
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"github.com/cheekybits/genny/generic"
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"github.com/MichaelMure/git-bug/graphql/models"
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)
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// Name define the name of the connection
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type Name generic.Type
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// NodeType define the node type handled by this relay connection
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type NodeType generic.Type
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// EdgeType define the edge type handled by this relay connection
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type EdgeType generic.Type
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// ConnectionType define the connection type handled by this relay connection
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type ConnectionType generic.Type
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// NodeTypeEdgeMaker define a function that take a NodeType and an offset and
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// create an Edge.
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type NameEdgeMaker func(value NodeType, offset int) Edge
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// NameConMaker define a function that create a ConnectionType
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type NameConMaker func(
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edges []*EdgeType,
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nodes []NodeType,
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info *models.PageInfo,
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totalCount int) (*ConnectionType, error)
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// NameCon will paginate a source according to the input of a relay connection
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func NameCon(source []NodeType, edgeMaker NameEdgeMaker, conMaker NameConMaker, input models.ConnectionInput) (*ConnectionType, error) {
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var nodes []NodeType
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var edges []*EdgeType
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var cursors []string
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var pageInfo = &models.PageInfo{}
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var totalCount = len(source)
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emptyCon, _ := conMaker(edges, nodes, pageInfo, 0)
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offset := 0
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if input.After != nil {
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for i, value := range source {
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edge := edgeMaker(value, i)
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if edge.GetCursor() == *input.After {
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// remove all previous element including the "after" one
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source = source[i+1:]
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offset = i + 1
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pageInfo.HasPreviousPage = true
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break
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}
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}
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}
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if input.Before != nil {
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for i, value := range source {
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edge := edgeMaker(value, i+offset)
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if edge.GetCursor() == *input.Before {
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// remove all after element including the "before" one
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pageInfo.HasNextPage = true
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break
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}
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e := edge.(EdgeType)
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edges = append(edges, &e)
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cursors = append(cursors, edge.GetCursor())
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nodes = append(nodes, value)
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}
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} else {
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edges = make([]*EdgeType, len(source))
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cursors = make([]string, len(source))
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nodes = source
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for i, value := range source {
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edge := edgeMaker(value, i+offset)
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e := edge.(EdgeType)
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edges[i] = &e
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cursors[i] = edge.GetCursor()
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}
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}
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if input.First != nil {
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if *input.First < 0 {
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return emptyCon, fmt.Errorf("first less than zero")
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}
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if len(edges) > *input.First {
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// Slice result to be of length first by removing edges from the end
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edges = edges[:*input.First]
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cursors = cursors[:*input.First]
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nodes = nodes[:*input.First]
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pageInfo.HasNextPage = true
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}
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}
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if input.Last != nil {
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if *input.Last < 0 {
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return emptyCon, fmt.Errorf("last less than zero")
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}
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if len(edges) > *input.Last {
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// Slice result to be of length last by removing edges from the start
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edges = edges[len(edges)-*input.Last:]
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cursors = cursors[len(cursors)-*input.Last:]
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nodes = nodes[len(nodes)-*input.Last:]
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pageInfo.HasPreviousPage = true
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}
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}
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// Fill up pageInfo cursors
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if len(cursors) > 0 {
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pageInfo.StartCursor = cursors[0]
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pageInfo.EndCursor = cursors[len(cursors)-1]
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}
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return conMaker(edges, nodes, pageInfo, totalCount)
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}
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