1 files changed, 77 insertions, 0 deletions
diff --git a/internal/mapr/whereclause.go b/internal/mapr/whereclause.go
new file mode 100644
index 0000000..cc1c164
--- /dev/null
+++ b/internal/mapr/whereclause.go
@@ -0,0 +1,77 @@
+package mapr
+
+import (
+	"strconv"
+
+	"github.com/mimecast/dtail/internal/io/logger"
+)
+
+// WhereClause interprets the where clause of the mapreduce query.
+func (q *Query) WhereClause(fields map[string]string) bool {
+	for _, wc := range q.Where {
+		var ok bool
+
+		if wc.Operation > FloatOperation {
+			var lValue, rValue float64
+			if lValue, ok = whereClauseFloatValue(fields, wc.lString, wc.lFloat, wc.lType); !ok {
+				return false
+			}
+			if rValue, ok = whereClauseFloatValue(fields, wc.rString, wc.rFloat, wc.rType); !ok {
+				return false
+			}
+			if ok = wc.floatClause(lValue, rValue); !ok {
+				return false
+			}
+			continue
+		}
+
+		var lValue, rValue string
+		if lValue, ok = whereClauseStringValue(fields, wc.lString, wc.lType); !ok {
+			return false
+		}
+		if rValue, ok = whereClauseStringValue(fields, wc.rString, wc.rType); !ok {
+			return false
+		}
+		if ok = wc.stringClause(lValue, rValue); !ok {
+			return false
+		}
+	}
+
+	return true
+}
+
+func whereClauseFloatValue(fields map[string]string, str string, float float64, t fieldType) (float64, bool) {
+	switch t {
+	case Float:
+		return float, true
+	case Field:
+		value, ok := fields[str]
+		if !ok {
+			return 0, false
+		}
+		f, err := strconv.ParseFloat(value, 64)
+		if err != nil {
+			return 0, false
+		}
+		return f, true
+	default:
+		logger.Error("Unexpected argument in 'where' clause", str, float, t)
+		return 0, false
+	}
+}
+
+func whereClauseStringValue(fields map[string]string, str string, t fieldType) (string, bool) {
+	switch t {
+	case Field:
+		value, ok := fields[str]
+		if !ok {
+			return str, false
+		}
+		return value, true
+	case String:
+		return str, true
+	default:
+		logger.Error("Unexpected argument in 'where' clause", str, t)
+		return str, false
+	}
+}