/* -*- 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 interface for managing user and user-agent style sheets */

#include "nsStyleSheetService.h"
#include "mozilla/CSSStyleSheet.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/StyleSheet.h"
#include "mozilla/StyleSheetInlines.h"
#include "mozilla/Unused.h"
#include "mozilla/css/Loader.h"
#include "mozilla/dom/ContentParent.h"
#include "mozilla/ipc/URIUtils.h"
#include "nsIURI.h"
#include "nsCOMPtr.h"
#include "nsICategoryManager.h"
#include "nsISupportsPrimitives.h"
#include "nsISimpleEnumerator.h"
#include "nsNetUtil.h"
#include "nsIObserverService.h"
#include "nsLayoutStatics.h"

using namespace mozilla;

nsStyleSheetService *nsStyleSheetService::gInstance = nullptr;

nsStyleSheetService::nsStyleSheetService()
{
  static_assert(0 == AGENT_SHEET && 1 == USER_SHEET && 2 == AUTHOR_SHEET,
                "Convention for Style Sheet");
  NS_ASSERTION(!gInstance, "Someone is using CreateInstance instead of GetService");
  gInstance = this;
  nsLayoutStatics::AddRef();
}

nsStyleSheetService::~nsStyleSheetService()
{
  UnregisterWeakMemoryReporter(this);

  gInstance = nullptr;
  nsLayoutStatics::Release();
}

NS_IMPL_ISUPPORTS(
  nsStyleSheetService, nsIStyleSheetService, nsIMemoryReporter)

void
nsStyleSheetService::RegisterFromEnumerator(nsICategoryManager  *aManager,
                                            const char          *aCategory,
                                            nsISimpleEnumerator *aEnumerator,
                                            uint32_t             aSheetType)
{
  if (!aEnumerator)
    return;

  bool hasMore;
  while (NS_SUCCEEDED(aEnumerator->HasMoreElements(&hasMore)) && hasMore) {
    nsCOMPtr<nsISupports> element;
    if (NS_FAILED(aEnumerator->GetNext(getter_AddRefs(element))))
      break;

    nsCOMPtr<nsISupportsCString> icStr = do_QueryInterface(element);
    NS_ASSERTION(icStr,
                 "category manager entries must be nsISupportsCStrings");

    nsAutoCString name;
    icStr->GetData(name);

    nsXPIDLCString spec;
    aManager->GetCategoryEntry(aCategory, name.get(), getter_Copies(spec));

    nsCOMPtr<nsIURI> uri;
    NS_NewURI(getter_AddRefs(uri), spec);
    if (uri)
      LoadAndRegisterSheetInternal(uri, aSheetType);
  }
}

int32_t
nsStyleSheetService::FindSheetByURI(const nsTArray<RefPtr<StyleSheet>>& aSheets,
                                    nsIURI* aSheetURI)
{
  for (int32_t i = aSheets.Length() - 1; i >= 0; i-- ) {
    bool bEqual;
    nsIURI* uri = aSheets[i]->GetSheetURI();
    if (uri
        && NS_SUCCEEDED(uri->Equals(aSheetURI, &bEqual))
        && bEqual) {
      return i;
    }
  }

  return -1;
}

nsresult
nsStyleSheetService::Init()
{
  // If you make changes here, consider whether
  // SVGDocument::EnsureNonSVGUserAgentStyleSheetsLoaded should be updated too.

  // Child processes get their style sheets from the ContentParent.
  if (XRE_IsContentProcess()) {
    return NS_OK;
  }

  // Enumerate all of the style sheet URIs registered in the category
  // manager and load them.

  nsCOMPtr<nsICategoryManager> catMan =
    do_GetService(NS_CATEGORYMANAGER_CONTRACTID);

  NS_ENSURE_TRUE(catMan, NS_ERROR_OUT_OF_MEMORY);

  nsCOMPtr<nsISimpleEnumerator> sheets;
  catMan->EnumerateCategory("agent-style-sheets", getter_AddRefs(sheets));
  RegisterFromEnumerator(catMan, "agent-style-sheets", sheets, AGENT_SHEET);

  catMan->EnumerateCategory("user-style-sheets", getter_AddRefs(sheets));
  RegisterFromEnumerator(catMan, "user-style-sheets", sheets, USER_SHEET);

  catMan->EnumerateCategory("author-style-sheets", getter_AddRefs(sheets));
  RegisterFromEnumerator(catMan, "author-style-sheets", sheets, AUTHOR_SHEET);

  RegisterWeakMemoryReporter(this);

  return NS_OK;
}

NS_IMETHODIMP
nsStyleSheetService::LoadAndRegisterSheet(nsIURI *aSheetURI,
                                          uint32_t aSheetType)
{
  nsresult rv = LoadAndRegisterSheetInternal(aSheetURI, aSheetType);
  if (NS_SUCCEEDED(rv)) {
    const char* message;
    switch (aSheetType) {
      case AGENT_SHEET:
        message = "agent-sheet-added";
        break;
      case USER_SHEET:
        message = "user-sheet-added";
        break;
      case AUTHOR_SHEET:
        message = "author-sheet-added";
        break;
      default:
        return NS_ERROR_INVALID_ARG;
    }
    nsCOMPtr<nsIObserverService> serv = services::GetObserverService();
    if (serv) {
      // We're guaranteed that the new sheet is the last sheet in
      // mSheets[aSheetType]

      // XXXheycam Once the nsStyleSheetService can hold ServoStyleSheets too,
      // we'll need to include them in the notification.
      StyleSheet* sheet = mSheets[aSheetType].LastElement();
      if (sheet->IsGecko()) {
        CSSStyleSheet* cssSheet = sheet->AsGecko();
        serv->NotifyObservers(NS_ISUPPORTS_CAST(nsIDOMCSSStyleSheet*, cssSheet),
                              message, nullptr);
      } else {
        NS_ERROR("stylo: can't notify observers of ServoStyleSheets");
      }
    }

    if (XRE_IsParentProcess()) {
      nsTArray<dom::ContentParent*> children;
      dom::ContentParent::GetAll(children);

      if (children.IsEmpty()) {
        return rv;
      }

      mozilla::ipc::URIParams uri;
      SerializeURI(aSheetURI, uri);

      for (uint32_t i = 0; i < children.Length(); i++) {
        Unused << children[i]->SendLoadAndRegisterSheet(uri, aSheetType);
      }
    }
  }
  return rv;
}

nsresult
nsStyleSheetService::LoadAndRegisterSheetInternal(nsIURI *aSheetURI,
                                                  uint32_t aSheetType)
{
  NS_ENSURE_ARG_POINTER(aSheetURI);

  css::SheetParsingMode parsingMode;
  switch (aSheetType) {
    case AGENT_SHEET:
      parsingMode = css::eAgentSheetFeatures;
      break;

    case USER_SHEET:
      parsingMode = css::eUserSheetFeatures;
      break;

    case AUTHOR_SHEET:
      parsingMode = css::eAuthorSheetFeatures;
      break;

    default:
      NS_WARNING("invalid sheet type argument");
      return NS_ERROR_INVALID_ARG;
  }

  // XXXheycam We'll need to load and register both a Gecko- and Servo-backed
  // style sheet.
  RefPtr<css::Loader> loader = new css::Loader(StyleBackendType::Gecko);

  RefPtr<StyleSheet> sheet;
  nsresult rv = loader->LoadSheetSync(aSheetURI, parsingMode, true, &sheet);
  NS_ENSURE_SUCCESS(rv, rv);

  mSheets[aSheetType].AppendElement(sheet);

  return rv;
}

NS_IMETHODIMP
nsStyleSheetService::SheetRegistered(nsIURI *sheetURI,
                                     uint32_t aSheetType, bool *_retval)
{
  NS_ENSURE_ARG(aSheetType == AGENT_SHEET ||
                aSheetType == USER_SHEET ||
                aSheetType == AUTHOR_SHEET);
  NS_ENSURE_ARG_POINTER(sheetURI);
  NS_PRECONDITION(_retval, "Null out param");

  *_retval = (FindSheetByURI(mSheets[aSheetType], sheetURI) >= 0);

  return NS_OK;
}

NS_IMETHODIMP
nsStyleSheetService::PreloadSheet(nsIURI *aSheetURI, uint32_t aSheetType,
                                  nsIDOMStyleSheet **aSheet)
{
  NS_PRECONDITION(aSheet, "Null out param");
  NS_ENSURE_ARG_POINTER(aSheetURI);
  css::SheetParsingMode parsingMode;
  switch (aSheetType) {
    case AGENT_SHEET:
      parsingMode = css::eAgentSheetFeatures;
      break;

    case USER_SHEET:
      parsingMode = css::eUserSheetFeatures;
      break;

    case AUTHOR_SHEET:
      parsingMode = css::eAuthorSheetFeatures;
      break;

    default:
      NS_WARNING("invalid sheet type argument");
      return NS_ERROR_INVALID_ARG;
  }

  // XXXheycam PreloadSheet can't support ServoStyleSheets until they implement
  // nsIDOMStyleSheet.

  RefPtr<css::Loader> loader = new css::Loader(StyleBackendType::Gecko);

  RefPtr<StyleSheet> sheet;
  nsresult rv = loader->LoadSheetSync(aSheetURI, parsingMode, true, &sheet);
  NS_ENSURE_SUCCESS(rv, rv);

  MOZ_ASSERT(sheet->IsGecko(),
             "stylo: didn't expect Loader to create a ServoStyleSheet");

  RefPtr<CSSStyleSheet> cssSheet = sheet->AsGecko();
  cssSheet.forget(aSheet);

  return NS_OK;
}

NS_IMETHODIMP
nsStyleSheetService::UnregisterSheet(nsIURI *aSheetURI, uint32_t aSheetType)
{
  NS_ENSURE_ARG(aSheetType == AGENT_SHEET ||
                aSheetType == USER_SHEET ||
                aSheetType == AUTHOR_SHEET);
  NS_ENSURE_ARG_POINTER(aSheetURI);

  int32_t foundIndex = FindSheetByURI(mSheets[aSheetType], aSheetURI);
  NS_ENSURE_TRUE(foundIndex >= 0, NS_ERROR_INVALID_ARG);
  RefPtr<StyleSheet> sheet = mSheets[aSheetType][foundIndex];
  mSheets[aSheetType].RemoveElementAt(foundIndex);

  const char* message;
  switch (aSheetType) {
    case AGENT_SHEET:
      message = "agent-sheet-removed";
      break;
    case USER_SHEET:
      message = "user-sheet-removed";
      break;
    case AUTHOR_SHEET:
      message = "author-sheet-removed";
      break;
  }

  nsCOMPtr<nsIObserverService> serv = services::GetObserverService();
  if (serv) {
    // XXXheycam Once the nsStyleSheetService can hold ServoStyleSheets too,
    // we'll need to include them in the notification.
    if (sheet->IsGecko()) {
      CSSStyleSheet* cssSheet = sheet->AsGecko();
      serv->NotifyObservers(NS_ISUPPORTS_CAST(nsIDOMCSSStyleSheet*, cssSheet),
                            message, nullptr);
    } else {
      NS_ERROR("stylo: can't notify observers of ServoStyleSheets");
    }
  }

  if (XRE_IsParentProcess()) {
    nsTArray<dom::ContentParent*> children;
    dom::ContentParent::GetAll(children);

    if (children.IsEmpty()) {
      return NS_OK;
    }

    mozilla::ipc::URIParams uri;
    SerializeURI(aSheetURI, uri);

    for (uint32_t i = 0; i < children.Length(); i++) {
      Unused << children[i]->SendUnregisterSheet(uri, aSheetType);
    }
  }

  return NS_OK;
}

//static
nsStyleSheetService *
nsStyleSheetService::GetInstance()
{
  static bool first = true;
  if (first) {
    // make sure at first call that it's inited
    nsCOMPtr<nsIStyleSheetService> dummy =
      do_GetService(NS_STYLESHEETSERVICE_CONTRACTID);
    first = false;
  }

  return gInstance;
}

MOZ_DEFINE_MALLOC_SIZE_OF(StyleSheetServiceMallocSizeOf)

NS_IMETHODIMP
nsStyleSheetService::CollectReports(nsIHandleReportCallback* aHandleReport,
                                    nsISupports* aData, bool aAnonymize)
{
  MOZ_COLLECT_REPORT(
    "explicit/layout/style-sheet-service", KIND_HEAP, UNITS_BYTES,
    SizeOfIncludingThis(StyleSheetServiceMallocSizeOf),
    "Memory used for style sheets held by the style sheet service.");

  return NS_OK;
}

size_t
nsStyleSheetService::SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
{
  size_t n = aMallocSizeOf(this);
  for (auto& sheetArray : mSheets) {
    n += sheetArray.ShallowSizeOfExcludingThis(aMallocSizeOf);
    for (StyleSheet* sheet : sheetArray) {
      n += sheet->SizeOfIncludingThis(aMallocSizeOf);
    }
  }
  return n;
}
