1 /* 2 * 3 * Copyright 2017, The Android Open Source Project 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 #ifndef ANDROID_TYPED_LOGGER_H 19 #define ANDROID_TYPED_LOGGER_H 20 21 // This is the client API for the typed logger. 22 23 #include <media/nblog/NBLog.h> 24 #include <algorithm> 25 26 /* 27 Fowler-Noll-Vo (FNV-1a) hash function for the file name. 28 Hashes at compile time. FNV-1a iterative function: 29 30 hash = offset_basis 31 for each byte to be hashed 32 hash = hash xor byte 33 hash = hash * FNV_prime 34 return hash 35 36 offset_basis and FNV_prime values depend on the size of the hash output 37 Following values are defined by FNV and should not be changed arbitrarily 38 */ 39 40 template<typename T> 41 constexpr T offset_basis(); 42 43 template<typename T> 44 constexpr T FNV_prime(); 45 46 template<> 47 constexpr uint32_t offset_basis<uint32_t>() { 48 return 2166136261u; 49 } 50 51 template<> 52 constexpr uint32_t FNV_prime<uint32_t>() { 53 return 16777619u; 54 } 55 56 template<> 57 constexpr uint64_t offset_basis<uint64_t>() { 58 return 14695981039346656037ull; 59 } 60 61 template<> 62 constexpr uint64_t FNV_prime<uint64_t>() { 63 return 1099511628211ull; 64 } 65 66 template <typename T, size_t n> 67 __attribute__((no_sanitize("unsigned-integer-overflow"))) 68 constexpr T fnv1a(const char (&file)[n], ssize_t i = (ssize_t)n - 1) { 69 return i == -1 ? offset_basis<T>() : (fnv1a<T>(file, i - 1) ^ file[i]) * FNV_prime<T>(); 70 } 71 72 template <size_t n> 73 constexpr uint64_t hash(const char (&file)[n], uint32_t line) { 74 // Line numbers over or equal to 2^16 are clamped to 2^16 - 1. This way increases collisions 75 // compared to wrapping around, but is easy to identify because it doesn't produce aliasing. 76 // It's a very unlikely case anyways. 77 return ((fnv1a<uint64_t>(file) << 16) ^ ((fnv1a<uint64_t>(file) >> 32) & 0xFFFF0000)) | 78 std::min(line, 0xFFFFu); 79 } 80 81 // TODO Permit disabling of logging at compile-time. 82 83 // TODO A non-nullptr dummy implementation that is a nop would be faster than checking for nullptr 84 // in the case when logging is enabled at compile-time and enabled at runtime, but it might be 85 // slower than nullptr check when logging is enabled at compile-time and disabled at runtime. 86 87 // Write formatted entry to log 88 #define LOGT(fmt, ...) do { NBLog::Writer *x = tlNBLogWriter; if (x != nullptr) \ 89 x->logFormat((fmt), hash(__FILE__, __LINE__), ##__VA_ARGS__); } \ 90 while (0) 91 92 // Write histogram timestamp entry 93 #define LOG_HIST_TS() do { NBLog::Writer *x = tlNBLogWriter; if (x != nullptr) \ 94 x->logEventHistTs(NBLog::EVENT_HISTOGRAM_ENTRY_TS, hash(__FILE__, __LINE__)); } while(0) 95 96 // Record that audio was turned on/off 97 #define LOG_AUDIO_STATE() do { NBLog::Writer *x = tlNBLogWriter; if (x != nullptr) \ 98 x->logEventHistTs(NBLog::EVENT_AUDIO_STATE, hash(__FILE__, __LINE__)); } while(0) 99 100 namespace android { 101 extern "C" { 102 extern thread_local NBLog::Writer *tlNBLogWriter; 103 } 104 } // namespace android 105 106 #endif // ANDROID_TYPED_LOGGER_H 107
