NativeFontResourceDWrite.cpp

/* -*- 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/. */

#include "NativeFontResourceDWrite.h"
#include "UnscaledFontDWrite.h"

#include <unordered_map>

#include "Logging.h"
#include "mozilla/RefPtr.h"
#include "mozilla/StaticMutex.h"
#include "nsTArray.h"

namespace mozilla {
namespace gfx {

static StaticMutex sFontFileStreamsMutex;
static uint64_t sNextFontFileKey = 0;
static std::unordered_map<uint64_t, IDWriteFontFileStream*> sFontFileStreams;

class DWriteFontFileLoader : public IDWriteFontFileLoader {
 public:
  DWriteFontFileLoader() {}

  // IUnknown interface
  IFACEMETHOD(QueryInterface)(IID const& iid, OUT void** ppObject) {
    if (iid == __uuidof(IDWriteFontFileLoader)) {
      *ppObject = static_cast<IDWriteFontFileLoader*>(this);
      return S_OK;
    } else if (iid == __uuidof(IUnknown)) {
      *ppObject = static_cast<IUnknown*>(this);
      return S_OK;
    } else {
      return E_NOINTERFACE;
    }
  }

  IFACEMETHOD_(ULONG, AddRef)() { return 1; }

  IFACEMETHOD_(ULONG, Release)() { return 1; }

  // IDWriteFontFileLoader methods
  /**
   * Important! Note the key here has to be a uint64_t that will have been
   * generated by incrementing sNextFontFileKey.
   */
  virtual HRESULT STDMETHODCALLTYPE CreateStreamFromKey(
      void const* fontFileReferenceKey, UINT32 fontFileReferenceKeySize,
      OUT IDWriteFontFileStream** fontFileStream);

  /**
   * Gets the singleton loader instance. Note that when using this font
   * loader, the key must be a uint64_t that has been generated by incrementing
   * sNextFontFileKey.
   * Also note that this is _not_ threadsafe.
   */
  static IDWriteFontFileLoader* Instance() {
    if (!mInstance) {
      mInstance = new DWriteFontFileLoader();
      Factory::GetDWriteFactory()->RegisterFontFileLoader(mInstance);
    }
    return mInstance;
  }

 private:
  static IDWriteFontFileLoader* mInstance;
};

class DWriteFontFileStream final : public IDWriteFontFileStream {
 public:
  explicit DWriteFontFileStream(uint64_t aFontFileKey);

  /**
   * Used by the FontFileLoader to create a new font stream,
   * this font stream is created from data in memory. The memory
   * passed may be released after object creation, it will be
   * copied internally.
   *
   * @param aData Font data
   */
  bool Initialize(uint8_t* aData, uint32_t aSize);

  // IUnknown interface
  IFACEMETHOD(QueryInterface)(IID const& iid, OUT void** ppObject) {
    if (iid == __uuidof(IDWriteFontFileStream)) {
      *ppObject = static_cast<IDWriteFontFileStream*>(this);
      return S_OK;
    } else if (iid == __uuidof(IUnknown)) {
      *ppObject = static_cast<IUnknown*>(this);
      return S_OK;
    } else {
      return E_NOINTERFACE;
    }
  }

  IFACEMETHOD_(ULONG, AddRef)() { return ++mRefCnt; }

  IFACEMETHOD_(ULONG, Release)() {
    uint32_t count = --mRefCnt;
    if (count == 0) {
      // Avoid locking unless necessary. Verify the refcount hasn't changed
      // while locked. Delete within the scope of the lock when zero.
      StaticMutexAutoLock lock(sFontFileStreamsMutex);
      if (0 != mRefCnt) {
        return mRefCnt;
      }
      delete this;
    }
    return count;
  }

  // IDWriteFontFileStream methods
  virtual HRESULT STDMETHODCALLTYPE
  ReadFileFragment(void const** fragmentStart, UINT64 fileOffset,
                   UINT64 fragmentSize, OUT void** fragmentContext);

  virtual void STDMETHODCALLTYPE ReleaseFileFragment(void* fragmentContext);

  virtual HRESULT STDMETHODCALLTYPE GetFileSize(OUT UINT64* fileSize);

  virtual HRESULT STDMETHODCALLTYPE GetLastWriteTime(OUT UINT64* lastWriteTime);

 private:
  nsTArray<uint8_t> mData;
  Atomic<uint32_t> mRefCnt;
  uint64_t mFontFileKey;

  ~DWriteFontFileStream();
};

IDWriteFontFileLoader* DWriteFontFileLoader::mInstance = nullptr;

HRESULT STDMETHODCALLTYPE DWriteFontFileLoader::CreateStreamFromKey(
    const void* fontFileReferenceKey, UINT32 fontFileReferenceKeySize,
    IDWriteFontFileStream** fontFileStream) {
  if (!fontFileReferenceKey || !fontFileStream) {
    return E_POINTER;
  }

  StaticMutexAutoLock lock(sFontFileStreamsMutex);
  uint64_t fontFileKey = *static_cast<const uint64_t*>(fontFileReferenceKey);
  auto found = sFontFileStreams.find(fontFileKey);
  if (found == sFontFileStreams.end()) {
    *fontFileStream = nullptr;
    return E_FAIL;
  }

  found->second->AddRef();
  *fontFileStream = found->second;
  return S_OK;
}

DWriteFontFileStream::DWriteFontFileStream(uint64_t aFontFileKey)
    : mRefCnt(0), mFontFileKey(aFontFileKey) {}

DWriteFontFileStream::~DWriteFontFileStream() {
  sFontFileStreams.erase(mFontFileKey);
}

bool DWriteFontFileStream::Initialize(uint8_t* aData, uint32_t aSize) {
  if (!mData.SetLength(aSize, fallible)) {
    return false;
  }
  memcpy(mData.Elements(), aData, aSize);
  return true;
}

HRESULT STDMETHODCALLTYPE DWriteFontFileStream::GetFileSize(UINT64* fileSize) {
  *fileSize = mData.Length();
  return S_OK;
}

HRESULT STDMETHODCALLTYPE
DWriteFontFileStream::GetLastWriteTime(UINT64* lastWriteTime) {
  return E_NOTIMPL;
}

HRESULT STDMETHODCALLTYPE DWriteFontFileStream::ReadFileFragment(
    const void** fragmentStart, UINT64 fileOffset, UINT64 fragmentSize,
    void** fragmentContext) {
  // We are required to do bounds checking.
  if (fileOffset + fragmentSize > mData.Length()) {
    return E_FAIL;
  }

  // truncate the 64 bit fileOffset to size_t sized index into mData
  size_t index = static_cast<size_t>(fileOffset);

  // We should be alive for the duration of this.
  *fragmentStart = &mData[index];
  *fragmentContext = nullptr;
  return S_OK;
}

void STDMETHODCALLTYPE
DWriteFontFileStream::ReleaseFileFragment(void* fragmentContext) {}

/* static */
already_AddRefed<NativeFontResourceDWrite> NativeFontResourceDWrite::Create(
    uint8_t* aFontData, uint32_t aDataLength) {
  RefPtr<IDWriteFactory> factory = Factory::GetDWriteFactory();
  if (!factory) {
    gfxWarning() << "Failed to get DWrite Factory.";
    return nullptr;
  }

  sFontFileStreamsMutex.Lock();
  uint64_t fontFileKey = sNextFontFileKey++;
  RefPtr<DWriteFontFileStream> ffsRef = new DWriteFontFileStream(fontFileKey);
  if (!ffsRef->Initialize(aFontData, aDataLength)) {
    sFontFileStreamsMutex.Unlock();
    gfxWarning() << "Failed to create DWriteFontFileStream.";
    return nullptr;
  }
  sFontFileStreams[fontFileKey] = ffsRef;
  sFontFileStreamsMutex.Unlock();

  RefPtr<IDWriteFontFile> fontFile;
  HRESULT hr = factory->CreateCustomFontFileReference(
      &fontFileKey, sizeof(fontFileKey), DWriteFontFileLoader::Instance(),
      getter_AddRefs(fontFile));
  if (FAILED(hr)) {
    gfxWarning() << "Failed to load font file from data!";
    return nullptr;
  }

  BOOL isSupported;
  DWRITE_FONT_FILE_TYPE fileType;
  DWRITE_FONT_FACE_TYPE faceType;
  UINT32 numberOfFaces;
  hr = fontFile->Analyze(&isSupported, &fileType, &faceType, &numberOfFaces);
  if (FAILED(hr) || !isSupported) {
    gfxWarning() << "Font file is not supported.";
    return nullptr;
  }

  RefPtr<NativeFontResourceDWrite> fontResource = new NativeFontResourceDWrite(
      factory, fontFile.forget(), ffsRef.forget(), faceType, numberOfFaces);
  return fontResource.forget();
}

already_AddRefed<UnscaledFont> NativeFontResourceDWrite::CreateUnscaledFont(
    uint32_t aIndex, const uint8_t* aInstanceData,
    uint32_t aInstanceDataLength) {
  if (aIndex >= mNumberOfFaces) {
    gfxWarning() << "Font face index is too high for font resource.";
    return nullptr;
  }

  IDWriteFontFile* fontFile = mFontFile;
  RefPtr<IDWriteFontFace> fontFace;
  if (FAILED(mFactory->CreateFontFace(mFaceType, 1, &fontFile, aIndex,
                                      DWRITE_FONT_SIMULATIONS_NONE,
                                      getter_AddRefs(fontFace)))) {
    gfxWarning() << "Failed to create font face from font file data.";
    return nullptr;
  }

  RefPtr<UnscaledFont> unscaledFont = new UnscaledFontDWrite(fontFace, nullptr);

  return unscaledFont.forget();
}

}  // namespace gfx
}  // namespace mozilla