enhanced and simplified Reset(), Clean() and Next() methods
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parent
d6bf5ee500
commit
ad3c1e5a60
213
data-cursor.go
213
data-cursor.go
@ -6,12 +6,14 @@ package expr
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import (
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"io"
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"slices"
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)
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type dataCursor struct {
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ds map[string]Functor
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ctx ExprContext
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initState bool // true if no item has prodiced yet (this replace di initial Next() call in the contructor)
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initState bool // true if no item has produced yet (this replace di initial Next() call in the contructor)
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// cursorValid bool // true if resource is nil or if clean has not yet been called
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index int
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count int
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current any
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@ -26,6 +28,7 @@ func NewDataCursor(ctx ExprContext, ds map[string]Functor, resource any) (dc *da
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dc = &dataCursor{
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ds: ds,
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initState: true,
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// cursorValid: true,
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index: -1,
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count: 0,
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current: nil,
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@ -36,7 +39,6 @@ func NewDataCursor(ctx ExprContext, ds map[string]Functor, resource any) (dc *da
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cleanFunc: ds[CleanName],
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resetFunc: ds[ResetName],
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}
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//dc.Next()
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return
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}
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@ -77,7 +79,7 @@ func (dc *dataCursor) String() string {
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}
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func (dc *dataCursor) HasOperation(name string) (exists bool) {
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exists = name == IndexName
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exists = slices.Contains([]string{CleanName, ResetName, CurrentName, IndexName}, name)
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if !exists {
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f, ok := dc.ds[name]
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exists = ok && isFunctor(f)
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@ -88,63 +90,83 @@ func (dc *dataCursor) HasOperation(name string) (exists bool) {
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func (dc *dataCursor) CallOperation(name string, args map[string]any) (value any, err error) {
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if name == IndexName {
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value = int64(dc.Index())
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} else if name == CleanName {
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err = dc.Clean()
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} else if name == ResetName {
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err = dc.Reset()
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} else if functor, ok := dc.ds[name]; ok && isFunctor(functor) {
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if functor == dc.cleanFunc {
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value, err = dc.Clean()
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} else if functor == dc.resetFunc {
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value, err = dc.Reset()
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} else {
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ctx := cloneContext(dc.ctx)
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value, err = functor.InvokeNamed(ctx, name, args)
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exportObjects(dc.ctx, ctx)
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}
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ctx := cloneContext(dc.ctx)
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value, err = functor.InvokeNamed(ctx, name, args)
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exportObjects(dc.ctx, ctx)
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} else {
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err = errNoOperation(name)
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}
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return
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}
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func (dc *dataCursor) Reset() (success bool, err error) {
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// func (dc *dataCursor) Reset() (err error) {
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// if dc.resetFunc != nil {
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// if dc.resource != nil {
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// ctx := cloneContext(dc.ctx)
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// actualParams := bindActualParams(dc.resetFunc, []any{dc.resource})
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// _, err = dc.resetFunc.InvokeNamed(ctx, ResetName, actualParams)
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// exportObjects(dc.ctx, ctx)
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// dc.index = -1
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// dc.count = 0
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// dc.initState = true
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// dc.current = nil
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// dc.lastErr = nil
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// } else {
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// err = errInvalidDataSource()
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// }
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// } else {
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// err = errNoOperation(ResetName)
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// }
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// return
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// }
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func (dc *dataCursor) Reset() (err error) {
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if dc.resetFunc != nil {
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if dc.resource != nil {
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ctx := cloneContext(dc.ctx)
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actualParams := bindActualParams(dc.resetFunc, []any{dc.resource})
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_, err = dc.resetFunc.InvokeNamed(ctx, ResetName, actualParams)
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exportObjects(dc.ctx, ctx)
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dc.index = -1
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dc.count = 0
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dc.initState = true
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dc.current = nil
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dc.lastErr = nil
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//dc.Next()
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} else {
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err = errInvalidDataSource()
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}
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} else {
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err = errNoOperation(ResetName)
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ctx := cloneContext(dc.ctx)
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actualParams := bindActualParams(dc.resetFunc, []any{dc.resource})
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_, err = dc.resetFunc.InvokeNamed(ctx, ResetName, actualParams)
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exportObjects(dc.ctx, ctx)
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}
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success = err == nil
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dc.index = -1
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dc.count = 0
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dc.initState = true
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dc.current = nil
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dc.lastErr = nil
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return
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}
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func (dc *dataCursor) Clean() (success bool, err error) {
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func (dc *dataCursor) Clean() (err error) {
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if dc.cleanFunc != nil {
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if dc.resource != nil {
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ctx := cloneContext(dc.ctx)
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actualParams := bindActualParams(dc.cleanFunc, []any{dc.resource})
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_, err = dc.cleanFunc.InvokeNamed(ctx, CleanName, actualParams)
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// dc.resource = nil
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exportObjects(dc.ctx, ctx)
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} else {
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err = errInvalidDataSource()
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}
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} else {
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err = errNoOperation(CleanName)
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ctx := cloneContext(dc.ctx)
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actualParams := bindActualParams(dc.cleanFunc, []any{dc.resource})
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_, err = dc.cleanFunc.InvokeNamed(ctx, CleanName, actualParams)
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exportObjects(dc.ctx, ctx)
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}
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success = err == nil
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dc.lastErr = io.EOF
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return
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}
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// func (dc *dataCursor) Clean() (err error) {
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// if dc.cleanFunc != nil {
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// if dc.resource != nil {
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// ctx := cloneContext(dc.ctx)
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// actualParams := bindActualParams(dc.cleanFunc, []any{dc.resource})
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// _, err = dc.cleanFunc.InvokeNamed(ctx, CleanName, actualParams)
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// exportObjects(dc.ctx, ctx)
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// } else {
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// err = errInvalidDataSource()
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// }
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// } else {
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// err = errNoOperation(CleanName)
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// }
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// return
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// }
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func (dc *dataCursor) Current() (item any, err error) { // must return io.EOF at the last item
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dc.init()
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@ -191,46 +213,89 @@ func (dc *dataCursor) Next() (current any, err error) { // must return io.EOF af
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return
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}
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current = dc.current
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if dc.resource != nil {
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filter := dc.ds[FilterName]
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mapper := dc.ds[MapName]
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var item any
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for item == nil && dc.lastErr == nil {
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ctx := cloneContext(dc.ctx)
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dc.index++
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filter := dc.ds[FilterName]
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mapper := dc.ds[MapName]
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var item any
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for item == nil && dc.lastErr == nil {
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ctx := cloneContext(dc.ctx)
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dc.index++
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actualParams := bindActualParams(dc.nextFunc, []any{dc.resource, dc.index})
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if item, dc.lastErr = dc.nextFunc.InvokeNamed(ctx, NextName, actualParams); dc.lastErr == nil {
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if item == nil {
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dc.lastErr = io.EOF
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} else {
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accepted := true
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if filter != nil {
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if accepted, dc.lastErr = dc.checkFilter(filter, item); dc.lastErr != nil || !accepted {
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item = nil
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}
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}
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if accepted {
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dc.count++
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}
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if item != nil && mapper != nil {
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item, dc.lastErr = dc.mapItem(mapper, item)
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actualParams := bindActualParams(dc.nextFunc, []any{dc.resource, dc.index})
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if item, dc.lastErr = dc.nextFunc.InvokeNamed(ctx, NextName, actualParams); dc.lastErr == nil {
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if item == nil {
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dc.lastErr = io.EOF
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} else {
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accepted := true
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if filter != nil {
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if accepted, dc.lastErr = dc.checkFilter(filter, item); dc.lastErr != nil || !accepted {
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item = nil
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}
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}
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if accepted {
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dc.count++
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}
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if item != nil && mapper != nil {
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item, dc.lastErr = dc.mapItem(mapper, item)
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}
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}
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exportObjects(dc.ctx, ctx)
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}
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dc.current = item
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if dc.lastErr != nil {
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dc.index--
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dc.Clean()
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}
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} else {
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dc.lastErr = errInvalidDataSource()
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exportObjects(dc.ctx, ctx)
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}
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dc.current = item
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if dc.lastErr != nil {
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dc.index--
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dc.Clean()
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}
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return
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}
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// func (dc *dataCursor) Next() (current any, err error) { // must return io.EOF after the last item
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// if dc.initState {
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// dc.init()
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// } else if err = dc.lastErr; err != nil {
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// return
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// }
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// current = dc.current
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// if dc.resource != nil {
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// filter := dc.ds[FilterName]
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// mapper := dc.ds[MapName]
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// var item any
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// for item == nil && dc.lastErr == nil {
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// ctx := cloneContext(dc.ctx)
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// dc.index++
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// actualParams := bindActualParams(dc.nextFunc, []any{dc.resource, dc.index})
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// if item, dc.lastErr = dc.nextFunc.InvokeNamed(ctx, NextName, actualParams); dc.lastErr == nil {
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// if item == nil {
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// dc.lastErr = io.EOF
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// } else {
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// accepted := true
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// if filter != nil {
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// if accepted, dc.lastErr = dc.checkFilter(filter, item); dc.lastErr != nil || !accepted {
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// item = nil
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// }
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// }
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// if accepted {
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// dc.count++
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// }
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// if item != nil && mapper != nil {
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// item, dc.lastErr = dc.mapItem(mapper, item)
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// }
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// }
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// }
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// exportObjects(dc.ctx, ctx)
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// }
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// dc.current = item
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// if dc.lastErr != nil {
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// dc.index--
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// dc.Clean()
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// }
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// } else {
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// dc.lastErr = errInvalidDataSource()
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// }
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// return
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// }
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func (dc *dataCursor) Index() int {
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return dc.index - 1
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}
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