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// Copyright (c) 2009 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef NET_BASE_NET_LOG_UTIL_H_
#define NET_BASE_NET_LOG_UTIL_H_
#include <string>
#include <vector>
#include "base/basictypes.h"
#include "net/base/capturing_net_log.h"
namespace net {
// The NetLogUtil utility class contains methods to analyze and visualize
// NetLog entries.
class NetLogUtil {
public:
struct EventDuration {
NetLog::EventType event;
base::TimeDelta duration;
};
typedef std::vector<EventDuration> EventDurationList;
// Builds a pretty printed ASCII tree showing the chronological order
// of events.
//
// The indentation reflects hiearchy, with the duration of each indented
// block noted on the right. The timestamp (tick count in milliseconds)
// is noted in the left column.
//
// This detailed view of what went into servicing a request can be used
// in logs, and is copy-pastable by users, for attaching to bug reports.
//
// Example A:
//
// t=0: +Event1 [dt = 8]
// t=1: +Event2 [dt = 0]
// t=1: EventX
// t=1: -Event2
// t=4: +Event3 [dt = 2]
// t=6: -Event3
// t=6: +Event2 [dt = 1]
// t=7: -Event2
// t=8: EventY
// t=8: -Event1
//
// Here we can see that:
// - Event1 started at t=0 and ended at t=8; the duration was 8 time units.
// - Event2 took place while Event1 was in progress, and was repeated
// at t=1 and t=6.
// - EventX took place while (the first) Event2 was in progress.
// - Event3 started and ended at the same time, taking 0 time.
// - EventY took place right before Event1 finished, at t=8
//
// In general the rules are:
// - Log entries added by BeginEvent() are prefixed with a '+' and
// start an indentation block.
// - Log entries added by EndEvent() are prefixed with a '-' and
// finish an indentation block.
// - Log entries added by AddEvent() have no prefix.
// - Time units are given as milliseconds.
//
static std::string PrettyPrintAsEventTree(
const std::vector<CapturingNetLog::Entry>& entries,
size_t num_entries_truncated);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(NetLogUtil);
};
} // namespace net
#endif // NET_BASE_NET_LOG_UTIL_H_
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