image/ImageFactory.cpp
author Henri Sivonen <hsivonen@hsivonen.fi>
Fri, 06 Jul 2018 10:44:43 +0300
changeset 489140 4ef0f163fdeb9afeddd87b37bfd987298c038542
parent 478246 7597bbcc9d66111326aa69048ad5847bdc7497f2
child 508163 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1402247 - Use encoding_rs for XPCOM string encoding conversions. r=Nika,erahm,froydnj. Correctness improvements: * UTF errors are handled safely per spec instead of dangerously truncating strings. * There are fewer converter implementations. Performance improvements: * The old code did exact buffer length math, which meant doing UTF math twice on each input string (once for length calculation and another time for conversion). Exact length math is more complicated when handling errors properly, which the old code didn't do. The new code does UTF math on the string content only once (when converting) but risks allocating more than once. There are heuristics in place to lower the probability of reallocation in cases where the double math avoidance isn't enough of a saving to absorb an allocation and memcpy. * Previously, in UTF-16 <-> UTF-8 conversions, an ASCII prefix was optimized but a single non-ASCII code point pessimized the rest of the string. The new code tries to get back on the fast ASCII path. * UTF-16 to Latin1 conversion guarantees less about handling of out-of-range input to eliminate an operation from the inner loop on x86/x86_64. * When assigning to a pre-existing string, the new code tries to reuse the old buffer instead of first releasing the old buffer and then allocating a new one. * When reallocating from the new code, the memcpy covers only the data that is part of the logical length of the old string instead of memcpying the whole capacity. (For old callers old excess memcpy behavior is preserved due to bogus callers. See bug 1472113.) * UTF-8 strings in XPConnect that are in the Latin1 range are passed to SpiderMonkey as Latin1. New features: * Conversion between UTF-8 and Latin1 is added in order to enable faster future interop between Rust code (or otherwise UTF-8-using code) and text node and SpiderMonkey code that uses Latin1. MozReview-Commit-ID: JaJuExfILM9

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * 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 "ImageFactory.h"

#include <algorithm>

#include "mozilla/Likely.h"

#include "nsIHttpChannel.h"
#include "nsIFileChannel.h"
#include "nsIFile.h"
#include "nsMimeTypes.h"
#include "nsIRequest.h"

#include "MultipartImage.h"
#include "RasterImage.h"
#include "VectorImage.h"
#include "Image.h"
#include "nsMediaFragmentURIParser.h"
#include "nsContentUtils.h"
#include "nsIScriptSecurityManager.h"

#include "gfxPrefs.h"

namespace mozilla {
namespace image {

/*static*/ void
ImageFactory::Initialize()
{ }

static uint32_t
ComputeImageFlags(nsIURI* uri, const nsCString& aMimeType, bool isMultiPart)
{
  nsresult rv;

  // We default to the static globals.
  bool isDiscardable = gfxPrefs::ImageMemDiscardable();
  bool doDecodeImmediately = gfxPrefs::ImageDecodeImmediatelyEnabled();

  // We want UI to be as snappy as possible and not to flicker. Disable
  // discarding for chrome URLS.
  bool isChrome = false;
  rv = uri->SchemeIs("chrome", &isChrome);
  if (NS_SUCCEEDED(rv) && isChrome) {
    isDiscardable = false;
  }

  // We don't want resources like the "loading" icon to be discardable either.
  bool isResource = false;
  rv = uri->SchemeIs("resource", &isResource);
  if (NS_SUCCEEDED(rv) && isResource) {
    isDiscardable = false;
  }

  // For multipart/x-mixed-replace, we basically want a direct channel to the
  // decoder. Disable everything for this case.
  if (isMultiPart) {
    isDiscardable = false;
  }

  // We have all the information we need.
  uint32_t imageFlags = Image::INIT_FLAG_NONE;
  if (isDiscardable) {
    imageFlags |= Image::INIT_FLAG_DISCARDABLE;
  }
  if (doDecodeImmediately) {
    imageFlags |= Image::INIT_FLAG_DECODE_IMMEDIATELY;
  }
  if (isMultiPart) {
    imageFlags |= Image::INIT_FLAG_TRANSIENT;
  }

  // Synchronously decode metadata (including size) if we have a data URI since
  // the data is immediately available.
  bool isDataURI = false;
  rv = uri->SchemeIs("data", &isDataURI);
  if (NS_SUCCEEDED(rv) && isDataURI) {
    imageFlags |= Image::INIT_FLAG_SYNC_LOAD;
  }

  return imageFlags;
}

#ifdef DEBUG
static void
NotifyImageLoading(nsIURI* aURI)
{
  if (!NS_IsMainThread()) {
    nsCOMPtr<nsIURI> uri(aURI);
    nsCOMPtr<nsIRunnable> ev =
      NS_NewRunnableFunction("NotifyImageLoading", [uri] () -> void {
        NotifyImageLoading(uri);
    });
    SystemGroup::Dispatch(TaskCategory::Other, ev.forget());
    return;
  }

  nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
  NS_WARNING_ASSERTION(obs, "Can't get an observer service handle");
  if (obs) {
    nsAutoCString spec;
    aURI->GetSpec(spec);
    obs->NotifyObservers(nullptr, "image-loading", NS_ConvertUTF8toUTF16(spec).get());
  }
}
#endif

/* static */ already_AddRefed<Image>
ImageFactory::CreateImage(nsIRequest* aRequest,
                          ProgressTracker* aProgressTracker,
                          const nsCString& aMimeType,
                          nsIURI* aURI,
                          bool aIsMultiPart,
                          uint32_t aInnerWindowId)
{
  MOZ_ASSERT(gfxPrefs::SingletonExists(),
             "Pref observers should have been initialized already");

  // Compute the image's initialization flags.
  uint32_t imageFlags = ComputeImageFlags(aURI, aMimeType, aIsMultiPart);

#ifdef DEBUG
  // Record the image load for startup performance testing.
  bool match = false;
  if ((NS_SUCCEEDED(aURI->SchemeIs("resource", &match)) && match) ||
      (NS_SUCCEEDED(aURI->SchemeIs("chrome", &match)) && match)) {
    NotifyImageLoading(aURI);
  }
#endif

  // Select the type of image to create based on MIME type.
  if (aMimeType.EqualsLiteral(IMAGE_SVG_XML)) {
    return CreateVectorImage(aRequest, aProgressTracker, aMimeType,
                             aURI, imageFlags, aInnerWindowId);
  } else {
    return CreateRasterImage(aRequest, aProgressTracker, aMimeType,
                             aURI, imageFlags, aInnerWindowId);
  }
}

// Marks an image as having an error before returning it.
template <typename T>
static already_AddRefed<Image>
BadImage(const char* aMessage, RefPtr<T>& aImage)
{
  aImage->SetHasError();
  return aImage.forget();
}

/* static */ already_AddRefed<Image>
ImageFactory::CreateAnonymousImage(const nsCString& aMimeType,
                                   uint32_t aSizeHint /* = 0 */)
{
  nsresult rv;

  RefPtr<RasterImage> newImage = new RasterImage();

  RefPtr<ProgressTracker> newTracker = new ProgressTracker();
  newTracker->SetImage(newImage);
  newImage->SetProgressTracker(newTracker);

  rv = newImage->Init(aMimeType.get(), Image::INIT_FLAG_SYNC_LOAD);
  if (NS_FAILED(rv)) {
    return BadImage("RasterImage::Init failed", newImage);
  }

  rv = newImage->SetSourceSizeHint(aSizeHint);
  if (NS_FAILED(rv)) {
    return BadImage("RasterImage::SetSourceSizeHint failed", newImage);
  }

  return newImage.forget();
}

/* static */ already_AddRefed<MultipartImage>
ImageFactory::CreateMultipartImage(Image* aFirstPart,
                                   ProgressTracker* aProgressTracker)
{
  MOZ_ASSERT(aFirstPart);
  MOZ_ASSERT(aProgressTracker);

  RefPtr<MultipartImage> newImage = new MultipartImage(aFirstPart);
  aProgressTracker->SetImage(newImage);
  newImage->SetProgressTracker(aProgressTracker);

  newImage->Init();

  return newImage.forget();
}

int32_t
SaturateToInt32(int64_t val)
{
  if (val > INT_MAX) {
    return INT_MAX;
  }
  if (val < INT_MIN) {
    return INT_MIN;
  }

  return static_cast<int32_t>(val);
}

uint32_t
GetContentSize(nsIRequest* aRequest)
{
  nsCOMPtr<nsIChannel> channel(do_QueryInterface(aRequest));
  if (channel) {
    int64_t size;
    nsresult rv = channel->GetContentLength(&size);
    if (NS_SUCCEEDED(rv)) {
      return std::max(SaturateToInt32(size), 0);
    }
  }

  // Use the file size as a size hint for file channels.
  nsCOMPtr<nsIFileChannel> fileChannel(do_QueryInterface(aRequest));
  if (fileChannel) {
    nsCOMPtr<nsIFile> file;
    nsresult rv = fileChannel->GetFile(getter_AddRefs(file));
    if (NS_SUCCEEDED(rv)) {
      int64_t filesize;
      rv = file->GetFileSize(&filesize);
      if (NS_SUCCEEDED(rv)) {
        return std::max(SaturateToInt32(filesize), 0);
      }
    }
  }

  // Fallback - neither http nor file. We'll use dynamic allocation.
  return 0;
}

/* static */ already_AddRefed<Image>
ImageFactory::CreateRasterImage(nsIRequest* aRequest,
                                ProgressTracker* aProgressTracker,
                                const nsCString& aMimeType,
                                nsIURI* aURI,
                                uint32_t aImageFlags,
                                uint32_t aInnerWindowId)
{
  MOZ_ASSERT(aProgressTracker);

  nsresult rv;

  RefPtr<RasterImage> newImage = new RasterImage(aURI);
  aProgressTracker->SetImage(newImage);
  newImage->SetProgressTracker(aProgressTracker);

  rv = newImage->Init(aMimeType.get(), aImageFlags);
  if (NS_FAILED(rv)) {
    return BadImage("RasterImage::Init failed", newImage);
  }

  newImage->SetInnerWindowID(aInnerWindowId);

  rv = newImage->SetSourceSizeHint(GetContentSize(aRequest));
  if (NS_FAILED(rv)) {
    return BadImage("RasterImage::SetSourceSizeHint failed", newImage);
  }

  return newImage.forget();
}

/* static */ already_AddRefed<Image>
ImageFactory::CreateVectorImage(nsIRequest* aRequest,
                                ProgressTracker* aProgressTracker,
                                const nsCString& aMimeType,
                                nsIURI* aURI,
                                uint32_t aImageFlags,
                                uint32_t aInnerWindowId)
{
  MOZ_ASSERT(aProgressTracker);

  nsresult rv;

  RefPtr<VectorImage> newImage = new VectorImage(aURI);
  aProgressTracker->SetImage(newImage);
  newImage->SetProgressTracker(aProgressTracker);

  rv = newImage->Init(aMimeType.get(), aImageFlags);
  if (NS_FAILED(rv)) {
    return BadImage("VectorImage::Init failed", newImage);
  }

  newImage->SetInnerWindowID(aInnerWindowId);

  rv = newImage->OnStartRequest(aRequest, nullptr);
  if (NS_FAILED(rv)) {
    return BadImage("VectorImage::OnStartRequest failed", newImage);
  }

  return newImage.forget();
}

} // namespace image
} // namespace mozilla