Initial QSfera import

Server/vendor/github.com/KimMachineGun/automemlimit/memlimit/provider.go

@@ -0,0 +1,43 @@
+package memlimit
+
+import (
+	"fmt"
+)
+
+// Provider is a function that returns the memory limit.
+type Provider func() (uint64, error)
+
+// Limit is a helper Provider function that returns the given limit.
+func Limit(limit uint64) func() (uint64, error) {
+	return func() (uint64, error) {
+		return limit, nil
+	}
+}
+
+// ApplyRationA is a helper Provider function that applies the given ratio to the given provider.
+func ApplyRatio(provider Provider, ratio float64) Provider {
+	if ratio == 1 {
+		return provider
+	}
+	return func() (uint64, error) {
+		if ratio <= 0 || ratio > 1 {
+			return 0, fmt.Errorf("invalid ratio: %f, ratio should be in the range (0.0,1.0]", ratio)
+		}
+		limit, err := provider()
+		if err != nil {
+			return 0, err
+		}
+		return uint64(float64(limit) * ratio), nil
+	}
+}
+
+// ApplyFallback is a helper Provider function that sets the fallback provider.
+func ApplyFallback(provider Provider, fallback Provider) Provider {
+	return func() (uint64, error) {
+		limit, err := provider()
+		if err != nil {
+			return fallback()
+		}
+		return limit, nil
+	}
+}