1/*
2 * Copyright 2018-present Facebook, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#pragma once
18
19#include <string>
20
21#include <folly/Function.h>
22#include <folly/Optional.h>
23#include <folly/Range.h>
24
25namespace folly {
26namespace io {
27enum class CodecType;
28} // namespace io
29
30enum class CompressionCounterKey {
31 BYTES_BEFORE_COMPRESSION = 0,
32 BYTES_AFTER_COMPRESSION = 1,
33 BYTES_BEFORE_DECOMPRESSION = 2,
34 BYTES_AFTER_DECOMPRESSION = 3,
35 COMPRESSIONS = 4,
36 DECOMPRESSIONS = 5,
37 COMPRESSION_MILLISECONDS = 6,
38 DECOMPRESSION_MILLISECONDS = 7,
39};
40
41enum class CompressionCounterType {
42 AVG = 0,
43 SUM = 1,
44};
45
46/**
47 * This functions is an extension point when FOLLY_HAVE_WEAK_SYMBOLS is true.
48 * There is a default no-op implementation provided which can be overrided by
49 * linking in a library which provides its own definition.
50 *
51 * @param codecType The type of the codec for this counter.
52 * @param codecName The name of the codec for this counter. If the codecName
53 * is empty it should be defaulted using the codecType.
54 * @param level Optionally the level used to construct the codec.
55 * @param key The key of the counter.
56 * @param counterType The type of the counter.
57 * @returns A function to increment the counter for the given key and
58 * type. It may be an empty folly::Function.
59 */
60folly::Function<void(double)> makeCompressionCounterHandler(
61 folly::io::CodecType codecType,
62 folly::StringPiece codecName,
63 folly::Optional<int> level,
64 CompressionCounterKey key,
65 CompressionCounterType counterType);
66
67namespace detail {
68
69/// Wrapper around the makeCompressionCounterHandler() extension point.
70class CompressionCounter {
71 public:
72 CompressionCounter() {}
73 CompressionCounter(
74 folly::io::CodecType codecType,
75 folly::StringPiece codecName,
76 folly::Optional<int> level,
77 CompressionCounterKey key,
78 CompressionCounterType counterType) {
79 initialize_ = [=]() {
80 return makeCompressionCounterHandler(
81 codecType, codecName, level, key, counterType);
82 };
83 DCHECK(!initialize_.hasAllocatedMemory());
84 }
85
86 void operator+=(double sum) {
87 performLazyInit();
88 if (increment_) {
89 increment_(sum);
90 }
91 }
92
93 void operator++() {
94 *this += 1.0;
95 }
96
97 void operator++(int) {
98 *this += 1.0;
99 }
100
101 bool hasImplementation() {
102 performLazyInit();
103 return static_cast<bool>(increment_);
104 }
105
106 private:
107 void performLazyInit() {
108 if (!initialized_) {
109 initialized_ = true;
110 increment_ = initialize_();
111 initialize_ = {};
112 }
113 }
114
115 bool initialized_{false};
116 folly::Function<folly::Function<void(double)>()> initialize_;
117 folly::Function<void(double)> increment_;
118};
119
120} // namespace detail
121} // namespace folly
122