From ef9874b6180fb32667505e08b04cd6ac784fe476 Mon Sep 17 00:00:00 2001
From: Gregory Eremin <g@erem.in>
Date: Tue, 12 Aug 2014 14:20:33 +0700
Subject: [PATCH] Buffer lookup func

---
 buffer.go      | 37 +++++++++++++++++++++++++++++++++++++
 buffer_test.go | 42 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+)

diff --git a/buffer.go b/buffer.go
index 62ff214..06b2248 100644
--- a/buffer.go
+++ b/buffer.go
@@ -59,6 +59,43 @@ func (b *Buffer) Flush() {
 	b.size = 0
 }
 
+// Searches for points of given series that matches provided conditions
+func (b *Buffer) Lookup(series string, conds map[string]interface{}) (res *influxdb.Series) {
+	s, ok := b.series[series]
+	if !ok {
+		return
+	}
+
+	// Building reversed column index
+	colind := make(map[string]int)
+	for i, name := range s.Columns {
+		colind[name] = i
+	}
+
+	for _, row := range s.Points {
+		good := true
+		for key, val := range conds {
+			ki, _ := colind[key]
+			if row[ki] != val {
+				good = false
+			}
+		}
+		if good {
+			// We need to return nil if there are no series/rows that matches condition
+			if res == nil {
+				res = &influxdb.Series{
+					Name:    s.Name,
+					Columns: s.Columns,
+					Points:  [][]interface{}{},
+				}
+			}
+			res.Points = append(res.Points, row)
+		}
+	}
+
+	return
+}
+
 // Closes buffer income channel and flushes all remaining series into database
 // It also terminates its aggregation coroutine
 func (b *Buffer) Close() {
diff --git a/buffer_test.go b/buffer_test.go
index 535806e..ad5cf44 100644
--- a/buffer_test.go
+++ b/buffer_test.go
@@ -52,6 +52,48 @@ func TestFlush(t *testing.T) {
 	}
 }
 
+func TestLookup(t *testing.T) {
+	fn := func(series []*influxdb.Series) {}
+	b := NewBuffer(10, fn)
+	b.Add(&influxdb.Series{
+		Name:    "foo",
+		Columns: []string{"a", "b", "c"},
+		Points:  [][]interface{}{{1, 2, 3}, {4, 5, 6}, {7, 8, 9}},
+	})
+
+	var res *influxdb.Series
+
+	// Should not match inexistent series
+	res = b.Lookup("bar", map[string]interface{}{})
+	if res != nil {
+		t.Error("Expected nil result, got non-nil")
+	}
+
+	// Should not match existent series with false condition
+	res = b.Lookup("bar", map[string]interface{}{"a": 2})
+	if res != nil {
+		t.Error("Expected nil result, got non-nil")
+	}
+
+	// Should match series with empty condition
+	res = b.Lookup("foo", map[string]interface{}{})
+	if res == nil {
+		t.Error("Expected non-nil result, got nil")
+	}
+	if len(res.Points) != 3 {
+		t.Errorf("Expected 3 resulting rows, got %d", len(res.Points))
+	}
+
+	// Should match series with true condition
+	res = b.Lookup("foo", map[string]interface{}{"a": 1})
+	if res == nil {
+		t.Error("Expected non-nil result, got nil")
+	}
+	if len(res.Points) != 1 {
+		t.Errorf("Expected 1 resulting rows, got %d", len(res.Points))
+	}
+}
+
 func TestClose(t *testing.T) {
 	fn := func(series []*influxdb.Series) {}
 	b := NewBuffer(10, fn)