gecko-dev/xpcom/ds/TimeStamp.cpp

92 строки
2.5 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*
* Implementation of the OS-independent methods of the TimeStamp class
*/
#include "mozilla/TimeStamp.h"
#include "prenv.h"
namespace mozilla {
/**
* Wrapper class used to initialize static data used by the TimeStamp class
*/
struct TimeStampInitialization
{
/**
* First timestamp taken when the class static initializers are run. This
* timestamp is used to sanitize timestamps coming from different sources.
*/
TimeStamp mFirstTimeStamp;
/**
* Timestamp representing the time when the process was created. This field
* is populated lazily the first time this information is required and is
* replaced every time the process is restarted.
*/
TimeStamp mProcessCreation;
TimeStampInitialization()
{
TimeStamp::Startup();
mFirstTimeStamp = TimeStamp::Now();
};
~TimeStampInitialization()
{
TimeStamp::Shutdown();
};
};
static TimeStampInitialization sInitOnce;
TimeStamp
TimeStamp::ProcessCreation(bool& aIsInconsistent)
{
aIsInconsistent = false;
if (sInitOnce.mProcessCreation.IsNull()) {
char* mozAppRestart = PR_GetEnv("MOZ_APP_RESTART");
TimeStamp ts;
/* When calling PR_SetEnv() with an empty value the existing variable may
* be unset or set to the empty string depending on the underlying platform
* thus we have to check if the variable is present and not empty. */
if (mozAppRestart && (strcmp(mozAppRestart, "") != 0)) {
/* Firefox was restarted, use the first time-stamp we've taken as the new
* process startup time. */
ts = sInitOnce.mFirstTimeStamp;
} else {
TimeStamp now = Now();
uint64_t uptime = ComputeProcessUptime();
ts = now - TimeDuration::FromMicroseconds(uptime);
if ((ts > sInitOnce.mFirstTimeStamp) || (uptime == 0)) {
/* If the process creation timestamp was inconsistent replace it with
* the first one instead and notify that a telemetry error was
* detected. */
aIsInconsistent = true;
ts = sInitOnce.mFirstTimeStamp;
}
}
sInitOnce.mProcessCreation = ts;
}
return sInitOnce.mProcessCreation;
}
void
TimeStamp::RecordProcessRestart()
{
sInitOnce.mProcessCreation = TimeStamp();
}
} // namespace mozilla