Michael Anthony Knyszek | 2159c26 | 2020-04-14 21:06:26 +0000 | [diff] [blame] | 1 | // Copyright 2020 The Go Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | package metrics |
| 6 | |
| 7 | import ( |
| 8 | "math" |
| 9 | "unsafe" |
| 10 | ) |
| 11 | |
| 12 | // ValueKind is a tag for a metric Value which indicates its type. |
| 13 | type ValueKind int |
| 14 | |
| 15 | const ( |
| 16 | // KindBad indicates that the Value has no type and should not be used. |
| 17 | KindBad ValueKind = iota |
| 18 | |
| 19 | // KindUint64 indicates that the type of the Value is a uint64. |
| 20 | KindUint64 |
| 21 | |
| 22 | // KindFloat64 indicates that the type of the Value is a float64. |
| 23 | KindFloat64 |
| 24 | |
| 25 | // KindFloat64Histogram indicates that the type of the Value is a *Float64Histogram. |
| 26 | KindFloat64Histogram |
| 27 | ) |
| 28 | |
| 29 | // Value represents a metric value returned by the runtime. |
| 30 | type Value struct { |
| 31 | kind ValueKind |
| 32 | scalar uint64 // contains scalar values for scalar Kinds. |
| 33 | pointer unsafe.Pointer // contains non-scalar values. |
| 34 | } |
| 35 | |
Ian Lance Taylor | c9d6f45 | 2021-02-07 15:25:39 -0800 | [diff] [blame] | 36 | // Kind returns the tag representing the kind of value this is. |
Michael Anthony Knyszek | 2159c26 | 2020-04-14 21:06:26 +0000 | [diff] [blame] | 37 | func (v Value) Kind() ValueKind { |
| 38 | return v.kind |
| 39 | } |
| 40 | |
| 41 | // Uint64 returns the internal uint64 value for the metric. |
| 42 | // |
| 43 | // If v.Kind() != KindUint64, this method panics. |
| 44 | func (v Value) Uint64() uint64 { |
| 45 | if v.kind != KindUint64 { |
| 46 | panic("called Uint64 on non-uint64 metric value") |
| 47 | } |
| 48 | return v.scalar |
| 49 | } |
| 50 | |
| 51 | // Float64 returns the internal float64 value for the metric. |
| 52 | // |
| 53 | // If v.Kind() != KindFloat64, this method panics. |
| 54 | func (v Value) Float64() float64 { |
| 55 | if v.kind != KindFloat64 { |
| 56 | panic("called Float64 on non-float64 metric value") |
| 57 | } |
| 58 | return math.Float64frombits(v.scalar) |
| 59 | } |
| 60 | |
| 61 | // Float64Histogram returns the internal *Float64Histogram value for the metric. |
| 62 | // |
| 63 | // If v.Kind() != KindFloat64Histogram, this method panics. |
| 64 | func (v Value) Float64Histogram() *Float64Histogram { |
| 65 | if v.kind != KindFloat64Histogram { |
Michael Anthony Knyszek | 4c668b2 | 2021-01-06 18:22:17 +0000 | [diff] [blame] | 66 | panic("called Float64Histogram on non-Float64Histogram metric value") |
Michael Anthony Knyszek | 2159c26 | 2020-04-14 21:06:26 +0000 | [diff] [blame] | 67 | } |
| 68 | return (*Float64Histogram)(v.pointer) |
| 69 | } |