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/* 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/. */
#include "mozilla/ProfileGatherer.h"
#include "mozilla/Services.h"
#include "nsIObserverService.h"
#include "GeckoSampler.h"
using mozilla::dom::AutoJSAPI;
using mozilla::dom::Promise;
namespace mozilla {
/**
* When a subprocess exits before we've gathered profiles, we'll
* store profiles for those processes until gathering starts. We'll
* only store up to MAX_SUBPROCESS_EXIT_PROFILES. The buffer is
* circular, so as soon as we receive another exit profile, we'll
* bump the oldest one out of the buffer.
*/
static const uint32_t MAX_SUBPROCESS_EXIT_PROFILES = 5;
NS_IMPL_ISUPPORTS(ProfileGatherer, nsIObserver)
ProfileGatherer::ProfileGatherer(GeckoSampler* aTicker)
: mTicker(aTicker)
, mSinceTime(0)
, mPendingProfiles(0)
, mGathering(false)
{
}
void
ProfileGatherer::GatheredOOPProfile()
{
MOZ_ASSERT(NS_IsMainThread());
if (!mGathering) {
// If we're not actively gathering, then we don't actually
// care that we gathered a profile here. This can happen for
// processes that exit while profiling.
return;
}
if (NS_WARN_IF(!mPromise)) {
// If we're not holding on to a Promise, then someone is
// calling us erroneously.
return;
}
mPendingProfiles--;
if (mPendingProfiles == 0) {
// We've got all of the async profiles now. Let's
// finish off the profile and resolve the Promise.
Finish();
}
}
void
ProfileGatherer::WillGatherOOPProfile()
{
mPendingProfiles++;
}
void
ProfileGatherer::Start(double aSinceTime,
Promise* aPromise)
{
MOZ_ASSERT(NS_IsMainThread());
if (mGathering) {
// If we're already gathering, reject the promise - this isn't going
// to end well.
if (aPromise) {
aPromise->MaybeReject(NS_ERROR_NOT_AVAILABLE);
}
return;
}
mSinceTime = aSinceTime;
mPromise = aPromise;
mGathering = true;
mPendingProfiles = 0;
nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
if (os) {
DebugOnly<nsresult> rv =
os->AddObserver(this, "profiler-subprocess", false);
NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "AddObserver failed");
rv = os->NotifyObservers(this, "profiler-subprocess-gather", nullptr);
NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "NotifyObservers failed");
}
if (!mPendingProfiles) {
Finish();
}
}
void
ProfileGatherer::Finish()
{
MOZ_ASSERT(NS_IsMainThread());
if (!mTicker) {
// We somehow got called after we were cancelled! This shouldn't
// be possible, but doing a belt-and-suspenders check to be sure.
return;
}
UniquePtr<char[]> buf = mTicker->ToJSON(mSinceTime);
nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
if (os) {
DebugOnly<nsresult> rv = os->RemoveObserver(this, "profiler-subprocess");
NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "RemoveObserver failed");
}
AutoJSAPI jsapi;
if (NS_WARN_IF(!jsapi.Init(mPromise->GlobalJSObject()))) {
// We're really hosed if we can't get a JS context for some reason.
Reset();
return;
}
JSContext* cx = jsapi.cx();
// Now parse the JSON so that we resolve with a JS Object.
JS::RootedValue val(cx);
{
NS_ConvertUTF8toUTF16 js_string(nsDependentCString(buf.get()));
if (!JS_ParseJSON(cx, static_cast<const char16_t*>(js_string.get()),
js_string.Length(), &val)) {
if (!jsapi.HasException()) {
mPromise->MaybeReject(NS_ERROR_DOM_UNKNOWN_ERR);
} else {
JS::RootedValue exn(cx);
DebugOnly<bool> gotException = jsapi.StealException(&exn);
MOZ_ASSERT(gotException);
jsapi.ClearException();
mPromise->MaybeReject(cx, exn);
}
} else {
mPromise->MaybeResolve(val);
}
}
Reset();
}
void
ProfileGatherer::Reset()
{
mSinceTime = 0;
mPromise = nullptr;
mPendingProfiles = 0;
mGathering = false;
}
void
ProfileGatherer::Cancel()
{
// The GeckoSampler is going away. If we have a Promise in flight, we
// should reject it.
if (mPromise) {
mPromise->MaybeReject(NS_ERROR_DOM_ABORT_ERR);
}
// Clear out the GeckoSampler reference, since it's being destroyed.
mTicker = nullptr;
}
void
ProfileGatherer::OOPExitProfile(const nsCString& aProfile)
{
if (mExitProfiles.Length() >= MAX_SUBPROCESS_EXIT_PROFILES) {
mExitProfiles.RemoveElementAt(0);
}
mExitProfiles.AppendElement(aProfile);
// If a process exited while gathering, we need to make
// sure we decrement the counter.
if (mGathering) {
GatheredOOPProfile();
}
}
NS_IMETHODIMP
ProfileGatherer::Observe(nsISupports* aSubject,
const char* aTopic,
const char16_t *someData)
{
if (!strcmp(aTopic, "profiler-subprocess")) {
nsCOMPtr<nsIProfileSaveEvent> pse = do_QueryInterface(aSubject);
if (pse) {
for (size_t i = 0; i < mExitProfiles.Length(); ++i) {
if (!mExitProfiles[i].IsEmpty()) {
pse->AddSubProfile(mExitProfiles[i].get());
}
}
mExitProfiles.Clear();
}
}
return NS_OK;
}
} // namespace mozilla
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