1 // Copyright (c) 2009 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef NET_BASE_LOAD_LOG_UTIL_H_ 6 #define NET_BASE_LOAD_LOG_UTIL_H_ 7 8 #include <string> 9 #include <vector> 10 11 #include "base/basictypes.h" 12 #include "net/base/load_log.h" 13 14 namespace net { 15 16 // The LoadLogUtil utility class contains methods to analyze and visualize 17 // LoadLogs. 18 19 class LoadLogUtil { 20 public: 21 struct EventDuration { 22 LoadLog::EventType event; 23 base::TimeDelta duration; 24 }; 25 typedef std::vector<EventDuration> EventDurationList; 26 27 // Builds a pretty printed ASCII tree showing the chronological order 28 // of events. 29 // 30 // The indentation reflects hiearchy, with the duration of each indented 31 // block noted on the right. The timestamp (tick count in milliseconds) 32 // is noted in the left column. 33 // 34 // This detailed view of what went into servicing a request can be used 35 // in logs, and is copy-pastable by users, for attaching to bug reports. 36 // 37 // Example A: 38 // 39 // t=0: +Event1 [dt = 8] 40 // t=1: +Event2 [dt = 0] 41 // t=1: EventX 42 // t=1: -Event2 43 // t=4: +Event3 [dt = 2] 44 // t=6: -Event3 45 // t=6: +Event2 [dt = 1] 46 // t=7: -Event2 47 // t=8: EventY 48 // t=8: -Event1 49 // 50 // Here we can see that: 51 // - Event1 started at t=0 and ended at t=8; the duration was 8 time units. 52 // - Event2 took place while Event1 was in progress, and was repeated 53 // at t=1 and t=6. 54 // - EventX took place while (the first) Event2 was in progress. 55 // - Event3 started and ended at the same time, taking 0 time. 56 // - EventY took place right before Event1 finished, at t=8 57 // 58 // In general the rules are: 59 // - Log entries added by BeginEvent() are prefixed with a '+' and 60 // start an indentation block. 61 // - Log entries added by EndEvent() are prefixed with a '-' and 62 // finish an indentation block. 63 // - Log entries added by AddEvent() have no prefix. 64 // - Time units are given as milliseconds. 65 // 66 static std::string PrettyPrintAsEventTree(const LoadLog* log); 67 68 private: 69 DISALLOW_IMPLICIT_CONSTRUCTORS(LoadLogUtil); 70 }; 71 72 } // namespace net 73 74 #endif // NET_BASE_LOAD_LOG_UTIL_H_ 75
