mirror of https://github.com/go-redis/redis.git
85 lines
1.6 KiB
Go
85 lines
1.6 KiB
Go
package redis
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import "sync"
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type Scanner struct {
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client *cmdable
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*ScanCmd
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}
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// Iterator creates a new ScanIterator.
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func (s Scanner) Iterator() *ScanIterator {
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return &ScanIterator{
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Scanner: s,
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}
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}
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// ScanIterator is used to incrementally iterate over a collection of elements.
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// It's safe for concurrent use by multiple goroutines.
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type ScanIterator struct {
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mu sync.Mutex // protects Scanner and pos
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Scanner
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pos int
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}
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// Err returns the last iterator error, if any.
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func (it *ScanIterator) Err() error {
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it.mu.Lock()
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err := it.ScanCmd.Err()
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it.mu.Unlock()
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return err
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}
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// Next advances the cursor and returns true if more values can be read.
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func (it *ScanIterator) Next() bool {
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it.mu.Lock()
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defer it.mu.Unlock()
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// Instantly return on errors.
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if it.ScanCmd.Err() != nil {
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return false
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}
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// Advance cursor, check if we are still within range.
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if it.pos < len(it.ScanCmd.page) {
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it.pos++
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return true
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}
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for {
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// Return if there is more data to fetch.
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if it.ScanCmd.cursor == 0 {
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return false
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}
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// Fetch next page.
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if it.ScanCmd._args[0] == "scan" {
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it.ScanCmd._args[1] = it.ScanCmd.cursor
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} else {
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it.ScanCmd._args[2] = it.ScanCmd.cursor
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}
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it.ScanCmd.reset()
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it.client.process(it.ScanCmd)
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if it.ScanCmd.Err() != nil {
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return false
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}
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it.pos = 1
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if len(it.ScanCmd.page) > 0 {
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return true
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}
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}
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return false
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}
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// Val returns the key/field at the current cursor position.
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func (it *ScanIterator) Val() string {
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var v string
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it.mu.Lock()
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if it.ScanCmd.Err() == nil && it.pos > 0 && it.pos <= len(it.ScanCmd.page) {
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v = it.ScanCmd.page[it.pos-1]
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}
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it.mu.Unlock()
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return v
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}
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