/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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/. */

#include <string>
#include <sstream>
#include "GeckoProfiler.h"
#include "nsIFileStreams.h"
#include "nsProfiler.h"
#include "nsProfilerStartParams.h"
#include "nsMemory.h"
#include "nsString.h"
#include "mozilla/Services.h"
#include "nsIObserverService.h"
#include "nsIInterfaceRequestor.h"
#include "nsILoadContext.h"
#include "nsIWebNavigation.h"
#include "nsIInterfaceRequestorUtils.h"
#include "shared-libraries.h"
#include "js/Value.h"
#include "mozilla/ErrorResult.h"
#include "mozilla/dom/Promise.h"
#include "mozilla/dom/TypedArray.h"
#include "nsLocalFile.h"
#include "nsThreadUtils.h"
#include "ProfilerParent.h"
#include "platform.h"

using namespace mozilla;

using dom::AutoJSAPI;
using dom::Promise;
using std::string;

NS_IMPL_ISUPPORTS(nsProfiler, nsIProfiler)

nsProfiler::nsProfiler()
  : mLockedForPrivateBrowsing(false)
  , mPendingProfiles(0)
  , mGathering(false)
{
}

nsProfiler::~nsProfiler()
{
  nsCOMPtr<nsIObserverService> observerService = mozilla::services::GetObserverService();
  if (observerService) {
    observerService->RemoveObserver(this, "chrome-document-global-created");
    observerService->RemoveObserver(this, "last-pb-context-exited");
  }
}

nsresult
nsProfiler::Init() {
  nsCOMPtr<nsIObserverService> observerService = mozilla::services::GetObserverService();
  if (observerService) {
    observerService->AddObserver(this, "chrome-document-global-created", false);
    observerService->AddObserver(this, "last-pb-context-exited", false);
  }
  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::Observe(nsISupports *aSubject,
                    const char *aTopic,
                    const char16_t *aData)
{
  // The profiler's handling of private browsing is as simple as possible: it
  // is stopped when the first PB window opens, and left stopped when the last
  // PB window closes.
  if (strcmp(aTopic, "chrome-document-global-created") == 0) {
    nsCOMPtr<nsIInterfaceRequestor> requestor = do_QueryInterface(aSubject);
    nsCOMPtr<nsIWebNavigation> parentWebNav = do_GetInterface(requestor);
    nsCOMPtr<nsILoadContext> loadContext = do_QueryInterface(parentWebNav);
    if (loadContext && loadContext->UsePrivateBrowsing() && !mLockedForPrivateBrowsing) {
      mLockedForPrivateBrowsing = true;
      profiler_stop();
    }
  } else if (strcmp(aTopic, "last-pb-context-exited") == 0) {
    mLockedForPrivateBrowsing = false;
  }
  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::CanProfile(bool *aCanProfile)
{
  *aCanProfile = !mLockedForPrivateBrowsing;
  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::StartProfiler(uint32_t aEntries, double aInterval,
                          const char** aFeatures, uint32_t aFeatureCount,
                          const char** aFilters, uint32_t aFilterCount)
{
  if (mLockedForPrivateBrowsing) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  ResetGathering();

  uint32_t features = ParseFeaturesFromStringArray(aFeatures, aFeatureCount);
  profiler_start(aEntries, aInterval, features, aFilters, aFilterCount);

  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::StopProfiler()
{
  // If we have a Promise in flight, we should reject it.
  if (mPromiseHolder.isSome()) {
    mPromiseHolder->RejectIfExists(NS_ERROR_DOM_ABORT_ERR, __func__);
  }
  mExitProfiles.Clear();
  ResetGathering();

  profiler_stop();

  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::IsPaused(bool *aIsPaused)
{
  *aIsPaused = profiler_is_paused();
  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::PauseSampling()
{
  profiler_pause();
  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::ResumeSampling()
{
  profiler_resume();
  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::AddMarker(const char *aMarker)
{
  profiler_add_marker(aMarker);
  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::GetProfile(double aSinceTime, char** aProfile)
{
  mozilla::UniquePtr<char[]> profile = profiler_get_profile(aSinceTime);
  if (profile) {
    size_t len = strlen(profile.get());
    char *profileStr = static_cast<char *>
                         (nsMemory::Clone(profile.get(), (len + 1) * sizeof(char)));
    profileStr[len] = '\0';
    *aProfile = profileStr;
  }
  return NS_OK;
}

namespace {
  struct StringWriteFunc : public JSONWriteFunc
  {
    nsAString& mBuffer; // This struct must not outlive this buffer
    explicit StringWriteFunc(nsAString& buffer) : mBuffer(buffer) {}

    void Write(const char* aStr)
    {
      mBuffer.Append(NS_ConvertUTF8toUTF16(aStr));
    }
  };
}

NS_IMETHODIMP
nsProfiler::GetSharedLibraries(JSContext* aCx,
                               JS::MutableHandle<JS::Value> aResult)
{
  JS::RootedValue val(aCx);
  {
    nsString buffer;
    JSONWriter w(MakeUnique<StringWriteFunc>(buffer));
    w.StartArrayElement();
    AppendSharedLibraries(w);
    w.EndArray();
    MOZ_ALWAYS_TRUE(JS_ParseJSON(aCx, static_cast<const char16_t*>(buffer.get()),
                                 buffer.Length(), &val));
  }
  JS::RootedObject obj(aCx, &val.toObject());
  if (!obj) {
    return NS_ERROR_FAILURE;
  }
  aResult.setObject(*obj);
  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::DumpProfileToFile(const char* aFilename)
{
  profiler_save_profile_to_file(aFilename);
  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::GetProfileData(double aSinceTime, JSContext* aCx,
                           JS::MutableHandle<JS::Value> aResult)
{
  mozilla::UniquePtr<char[]> profile = profiler_get_profile(aSinceTime);
  if (!profile) {
    return NS_ERROR_FAILURE;
  }

  NS_ConvertUTF8toUTF16 js_string(nsDependentCString(profile.get()));
  auto profile16 = static_cast<const char16_t*>(js_string.get());

  JS::RootedValue val(aCx);
  MOZ_ALWAYS_TRUE(JS_ParseJSON(aCx, profile16, js_string.Length(), &val));

  aResult.set(val);
  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::GetProfileDataAsync(double aSinceTime, JSContext* aCx,
                                nsISupports** aPromise)
{
  MOZ_ASSERT(NS_IsMainThread());

  if (!profiler_is_active()) {
    return NS_ERROR_FAILURE;
  }

  if (NS_WARN_IF(!aCx)) {
    return NS_ERROR_FAILURE;
  }

  nsIGlobalObject* globalObject =
    xpc::NativeGlobal(JS::CurrentGlobalOrNull(aCx));

  if (NS_WARN_IF(!globalObject)) {
    return NS_ERROR_FAILURE;
  }

  ErrorResult result;
  RefPtr<Promise> promise = Promise::Create(globalObject, result);
  if (NS_WARN_IF(result.Failed())) {
    return result.StealNSResult();
  }

  StartGathering(aSinceTime)->Then(
    GetMainThreadSerialEventTarget(), __func__,
    [promise](nsCString aResult) {
      AutoJSAPI jsapi;
      if (NS_WARN_IF(!jsapi.Init(promise->GlobalJSObject()))) {
        // We're really hosed if we can't get a JS context for some reason.
        promise->MaybeReject(NS_ERROR_DOM_UNKNOWN_ERR);
        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(aResult);
        if (!JS_ParseJSON(cx, static_cast<const char16_t*>(js_string.get()),
                          js_string.Length(), &val)) {
          if (!jsapi.HasException()) {
            promise->MaybeReject(NS_ERROR_DOM_UNKNOWN_ERR);
          } else {
            JS::RootedValue exn(cx);
            DebugOnly<bool> gotException = jsapi.StealException(&exn);
            MOZ_ASSERT(gotException);

            jsapi.ClearException();
            promise->MaybeReject(cx, exn);
          }
        } else {
          promise->MaybeResolve(val);
        }
      }
    },
    [promise](nsresult aRv) {
      promise->MaybeReject(aRv);
    });

  promise.forget(aPromise);
  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::GetProfileDataAsArrayBuffer(double aSinceTime, JSContext* aCx,
                                        nsISupports** aPromise)
{
  MOZ_ASSERT(NS_IsMainThread());

  if (!profiler_is_active()) {
    return NS_ERROR_FAILURE;
  }

  if (NS_WARN_IF(!aCx)) {
    return NS_ERROR_FAILURE;
  }

  nsIGlobalObject* globalObject =
    xpc::NativeGlobal(JS::CurrentGlobalOrNull(aCx));

  if (NS_WARN_IF(!globalObject)) {
    return NS_ERROR_FAILURE;
  }

  ErrorResult result;
  RefPtr<Promise> promise = Promise::Create(globalObject, result);
  if (NS_WARN_IF(result.Failed())) {
    return result.StealNSResult();
  }

  StartGathering(aSinceTime)->Then(
    GetMainThreadSerialEventTarget(), __func__,
    [promise](nsCString aResult) {
      AutoJSAPI jsapi;
      if (NS_WARN_IF(!jsapi.Init(promise->GlobalJSObject()))) {
        // We're really hosed if we can't get a JS context for some reason.
        promise->MaybeReject(NS_ERROR_DOM_UNKNOWN_ERR);
        return;
      }

      JSContext* cx = jsapi.cx();
      JSObject* typedArray =
        dom::ArrayBuffer::Create(cx, aResult.Length(),
                                 reinterpret_cast<const uint8_t*>(aResult.Data()));
      if (typedArray) {
        JS::RootedValue val(cx, JS::ObjectValue(*typedArray));
        promise->MaybeResolve(val);
      } else {
        promise->MaybeReject(NS_ERROR_OUT_OF_MEMORY);
      }
    },
    [promise](nsresult aRv) {
      promise->MaybeReject(aRv);
    });

  promise.forget(aPromise);
  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::DumpProfileToFileAsync(const nsACString& aFilename,
                                   double aSinceTime, JSContext* aCx,
                                   nsISupports** aPromise)
{
  MOZ_ASSERT(NS_IsMainThread());

  if (!profiler_is_active()) {
    return NS_ERROR_FAILURE;
  }

  if (NS_WARN_IF(!aCx)) {
    return NS_ERROR_FAILURE;
  }

  nsIGlobalObject* globalObject =
    xpc::NativeGlobal(JS::CurrentGlobalOrNull(aCx));

  if (NS_WARN_IF(!globalObject)) {
    return NS_ERROR_FAILURE;
  }

  ErrorResult result;
  RefPtr<Promise> promise = Promise::Create(globalObject, result);
  if (NS_WARN_IF(result.Failed())) {
    return result.StealNSResult();
  }

  nsCString filename(aFilename);

  StartGathering(aSinceTime)->Then(
    GetMainThreadSerialEventTarget(), __func__,
    [filename, promise](const nsCString& aResult) {
      nsCOMPtr<nsIFile> file = do_CreateInstance(NS_LOCAL_FILE_CONTRACTID);
      nsresult rv = file->InitWithNativePath(filename);
      if (NS_FAILED(rv)) {
        MOZ_CRASH();
      }
      nsCOMPtr<nsIFileOutputStream> of =
        do_CreateInstance("@mozilla.org/network/file-output-stream;1");
      of->Init(file, -1, -1, 0);
      uint32_t sz;
      of->Write(aResult.get(), aResult.Length(), &sz);
      of->Close();

      promise->MaybeResolveWithUndefined();
    },
    [promise](nsresult aRv) {
      promise->MaybeReject(aRv);
    });

  promise.forget(aPromise);
  return NS_OK;
}


NS_IMETHODIMP
nsProfiler::GetElapsedTime(double* aElapsedTime)
{
  *aElapsedTime = profiler_time();
  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::IsActive(bool *aIsActive)
{
  *aIsActive = profiler_is_active();
  return NS_OK;
}

static void
GetArrayOfStringsForFeatures(uint32_t aFeatures,
                             uint32_t* aCount, char*** aFeatureList)
{
  #define COUNT_IF_SET(n_, str_, Name_) \
    if (ProfilerFeature::Has##Name_(aFeatures)) { \
      len++; \
    }

  // Count the number of features in use.
  uint32_t len = 0;
  PROFILER_FOR_EACH_FEATURE(COUNT_IF_SET)

  #undef COUNT_IF_SET

  auto featureList = static_cast<char**>(moz_xmalloc(len * sizeof(char*)));

  #define DUP_IF_SET(n_, str_, Name_) \
    if (ProfilerFeature::Has##Name_(aFeatures)) { \
      size_t strLen = strlen(str_); \
      featureList[i] = static_cast<char*>( \
        nsMemory::Clone(str_, (strLen + 1) * sizeof(char))); \
      i++; \
    }

  // Insert the strings for the features in use.
  size_t i = 0;
  PROFILER_FOR_EACH_FEATURE(DUP_IF_SET)

  #undef DUP_IF_SET

  *aFeatureList = featureList;
  *aCount = len;
}

NS_IMETHODIMP
nsProfiler::GetFeatures(uint32_t* aCount, char*** aFeatureList)
{
  uint32_t features = profiler_get_available_features();
  GetArrayOfStringsForFeatures(features, aCount, aFeatureList);
  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::GetAllFeatures(uint32_t* aCount, char*** aFeatureList)
{
  GetArrayOfStringsForFeatures((uint32_t)-1, aCount, aFeatureList);
  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::GetStartParams(nsIProfilerStartParams** aRetVal)
{
  if (!profiler_is_active()) {
    *aRetVal = nullptr;
  } else {
    int entries = 0;
    double interval = 0;
    uint32_t features = 0;
    mozilla::Vector<const char*> filters;
    profiler_get_start_params(&entries, &interval, &features, &filters);

    nsTArray<nsCString> filtersArray;
    for (uint32_t i = 0; i < filters.length(); ++i) {
      filtersArray.AppendElement(filters[i]);
    }

    nsCOMPtr<nsIProfilerStartParams> startParams =
      new nsProfilerStartParams(entries, interval, features, filtersArray);

    startParams.forget(aRetVal);
  }
  return NS_OK;
}

NS_IMETHODIMP
nsProfiler::GetBufferInfo(uint32_t* aCurrentPosition, uint32_t* aTotalSize,
                          uint32_t* aGeneration)
{
  MOZ_ASSERT(aCurrentPosition);
  MOZ_ASSERT(aTotalSize);
  MOZ_ASSERT(aGeneration);
  profiler_get_buffer_info(aCurrentPosition, aTotalSize, aGeneration);
  return NS_OK;
}

void
nsProfiler::GatheredOOPProfile(const nsACString& aProfile)
{
  MOZ_RELEASE_ASSERT(NS_IsMainThread());

  if (!profiler_is_active()) {
    return;
  }

  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;
  }

  MOZ_RELEASE_ASSERT(mWriter.isSome(),
                     "Should always have a writer if mGathering is true");

  if (!aProfile.IsEmpty()) {
    mWriter->Splice(PromiseFlatCString(aProfile).get());
  }

  mPendingProfiles--;

  if (mPendingProfiles == 0) {
    // We've got all of the async profiles now. Let's
    // finish off the profile and resolve the Promise.
    FinishGathering();
  }
}

// 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;

void
nsProfiler::ReceiveShutdownProfile(const nsCString& aProfile)
{
  MOZ_RELEASE_ASSERT(NS_IsMainThread());

  if (!profiler_is_active()) {
    return;
  }

  // Append the exit profile to mExitProfiles so that it can be picked up the
  // next time a profile is requested. If we're currently gathering a profile,
  // do not add this exit profile to it; chances are that we already have a
  // profile from the exiting process and we don't want another one.
  // We only keep around at most MAX_SUBPROCESS_EXIT_PROFILES exit profiles.
  if (mExitProfiles.Length() >= MAX_SUBPROCESS_EXIT_PROFILES) {
    mExitProfiles.RemoveElementAt(0);
  }
  mExitProfiles.AppendElement(ExitProfile{ aProfile, TimeStamp::Now() });
}

RefPtr<nsProfiler::GatheringPromise>
nsProfiler::StartGathering(double aSinceTime)
{
  MOZ_RELEASE_ASSERT(NS_IsMainThread());

  if (mGathering) {
    // If we're already gathering, return a rejected promise - this isn't
    // going to end well.
    return GatheringPromise::CreateAndReject(NS_ERROR_NOT_AVAILABLE, __func__);
  }

  mGathering = true;

  // Request profiles from the other processes. This will trigger asynchronous
  // calls to ProfileGatherer::GatheredOOPProfile as the profiles arrive.
  //
  // Do this before the call to profiler_stream_json_for_this_process() because
  // that call is slow and we want to let the other processes grab their
  // profiles as soon as possible.
  nsTArray<RefPtr<ProfilerParent::SingleProcessProfilePromise>> profiles =
    ProfilerParent::GatherProfiles();

  mWriter.emplace();

  TimeStamp thisProcessFirstSampleTime;

  // Start building up the JSON result and grab the profile from this process.
  mWriter->Start(SpliceableJSONWriter::SingleLineStyle);
  if (!profiler_stream_json_for_this_process(*mWriter, aSinceTime,
                                             /* aIsShuttingDown */ true,
                                             &thisProcessFirstSampleTime)) {
    // The profiler is inactive. This either means that it was inactive even
    // at the time that ProfileGatherer::Start() was called, or that it was
    // stopped on a different thread since that call. Either way, we need to
    // reject the promise and stop gathering.
    return GatheringPromise::CreateAndReject(NS_ERROR_NOT_AVAILABLE, __func__);
  }

  mWriter->StartArrayProperty("processes");

  // If we have any process exit profiles, add them immediately, and clear
  // mExitProfiles.
  for (auto& exitProfile : mExitProfiles) {
    if (thisProcessFirstSampleTime &&
        exitProfile.mGatherTime < thisProcessFirstSampleTime) {
      // Don't include exit profiles that have no overlap with the profile
      // from our own process.
      continue;
    }
    if (!exitProfile.mJSON.IsEmpty()) {
      mWriter->Splice(exitProfile.mJSON.get());
    }
  }
  mExitProfiles.Clear();

  mPromiseHolder.emplace();
  RefPtr<GatheringPromise> promise = mPromiseHolder->Ensure(__func__);

  // Keep the array property "processes" and the root object in mWriter open
  // until FinishGathering() is called. As profiles from the other processes
  // come in, they will be inserted and end up in the right spot.
  // FinishGathering() will close the array and the root object.

  mPendingProfiles = profiles.Length();
  RefPtr<nsProfiler> self = this;
  for (auto profile : profiles) {
    profile->Then(GetMainThreadSerialEventTarget(), __func__,
      [self](const nsCString& aResult) {
        self->GatheredOOPProfile(aResult);
      },
      [self](ipc::PromiseRejectReason aReason) {
        self->GatheredOOPProfile(NS_LITERAL_CSTRING(""));
      });
  }
  if (!mPendingProfiles) {
    FinishGathering();
  }

  return promise;
}

void
nsProfiler::FinishGathering()
{
  MOZ_RELEASE_ASSERT(NS_IsMainThread());
  MOZ_RELEASE_ASSERT(mWriter.isSome());
  MOZ_RELEASE_ASSERT(mPromiseHolder.isSome());

  // Close the "processes" array property.
  mWriter->EndArray();

  // Close the root object of the generated JSON.
  mWriter->End();

  UniquePtr<char[]> buf = mWriter->WriteFunc()->CopyData();
  nsCString result(buf.get());
  mPromiseHolder->Resolve(result, __func__);

  ResetGathering();
}

void
nsProfiler::ResetGathering()
{
  mPromiseHolder.reset();
  mPendingProfiles = 0;
  mGathering = false;
  mWriter.reset();
}

