src: Add DMA localagent

[barometer.git] / src / dma / vendor / github.com / go-redis / redis / iterator.go

diff --git a/src/dma/vendor/github.com/go-redis/redis/iterator.go b/src/dma/vendor/github.com/go-redis/redis/iterator.go
new file mode 100644 (file)
index 0000000..5d4bedf
--- /dev/null
+++ b/src/dma/vendor/github.com/go-redis/redis/iterator.go
@@ -0,0 +1,73 @@
+package redis
+
+import "sync"
+
+// ScanIterator is used to incrementally iterate over a collection of elements.
+// It's safe for concurrent use by multiple goroutines.
+type ScanIterator struct {
+       mu  sync.Mutex // protects Scanner and pos
+       cmd *ScanCmd
+       pos int
+}
+
+// Err returns the last iterator error, if any.
+func (it *ScanIterator) Err() error {
+       it.mu.Lock()
+       err := it.cmd.Err()
+       it.mu.Unlock()
+       return err
+}
+
+// Next advances the cursor and returns true if more values can be read.
+func (it *ScanIterator) Next() bool {
+       it.mu.Lock()
+       defer it.mu.Unlock()
+
+       // Instantly return on errors.
+       if it.cmd.Err() != nil {
+               return false
+       }
+
+       // Advance cursor, check if we are still within range.
+       if it.pos < len(it.cmd.page) {
+               it.pos++
+               return true
+       }
+
+       for {
+               // Return if there is no more data to fetch.
+               if it.cmd.cursor == 0 {
+                       return false
+               }
+
+               // Fetch next page.
+               if it.cmd._args[0] == "scan" {
+                       it.cmd._args[1] = it.cmd.cursor
+               } else {
+                       it.cmd._args[2] = it.cmd.cursor
+               }
+
+               err := it.cmd.process(it.cmd)
+               if err != nil {
+                       return false
+               }
+
+               it.pos = 1
+
+               // Redis can occasionally return empty page.
+               if len(it.cmd.page) > 0 {
+                       return true
+               }
+       }
+}
+
+// Val returns the key/field at the current cursor position.
+func (it *ScanIterator) Val() string {
+       var v string
+       it.mu.Lock()
+       if it.cmd.Err() == nil && it.pos > 0 && it.pos <= len(it.cmd.page) {
+               v = it.cmd.page[it.pos-1]
+       }
+       it.mu.Unlock()
+       return v
+}