diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/src/utils/win/SkDWriteFontFileStream.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/skia/trunk/src/utils/win/SkDWriteFontFileStream.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,232 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkTypes.h"
+#include "SkDWriteFontFileStream.h"
+#include "SkHRESULT.h"
+#include "SkTemplates.h"
+#include "SkTFitsIn.h"
+#include "SkTScopedComPtr.h"
+
+#include <dwrite.h>
+
+///////////////////////////////////////////////////////////////////////////////
+//  SkIDWriteFontFileStream
+
+SkDWriteFontFileStream::SkDWriteFontFileStream(IDWriteFontFileStream* fontFileStream)
+    : fFontFileStream(SkRefComPtr(fontFileStream))
+    , fPos(0)
+    , fLockedMemory(NULL)
+    , fFragmentLock(NULL) {
+}
+
+SkDWriteFontFileStream::~SkDWriteFontFileStream() {
+    if (fFragmentLock) {
+        fFontFileStream->ReleaseFileFragment(fFragmentLock);
+    }
+}
+
+size_t SkDWriteFontFileStream::read(void* buffer, size_t size) {
+    HRESULT hr = S_OK;
+
+    if (NULL == buffer) {
+        size_t fileSize = this->getLength();
+
+        if (fPos + size > fileSize) {
+            size_t skipped = fileSize - fPos;
+            fPos = fileSize;
+            return skipped;
+        } else {
+            fPos += size;
+            return size;
+        }
+    }
+
+    const void* start;
+    void* fragmentLock;
+    hr = fFontFileStream->ReadFileFragment(&start, fPos, size, &fragmentLock);
+    if (SUCCEEDED(hr)) {
+        memcpy(buffer, start, size);
+        fFontFileStream->ReleaseFileFragment(fragmentLock);
+        fPos += size;
+        return size;
+    }
+
+    //The read may have failed because we asked for too much data.
+    size_t fileSize = this->getLength();
+    if (fPos + size <= fileSize) {
+        //This means we were within bounds, but failed for some other reason.
+        return 0;
+    }
+
+    size_t read = fileSize - fPos;
+    hr = fFontFileStream->ReadFileFragment(&start, fPos, read, &fragmentLock);
+    if (SUCCEEDED(hr)) {
+        memcpy(buffer, start, read);
+        fFontFileStream->ReleaseFileFragment(fragmentLock);
+        fPos = fileSize;
+        return read;
+    }
+
+    return 0;
+}
+
+bool SkDWriteFontFileStream::isAtEnd() const {
+    return fPos == this->getLength();
+}
+
+bool SkDWriteFontFileStream::rewind() {
+    fPos = 0;
+    return true;
+}
+
+SkDWriteFontFileStream* SkDWriteFontFileStream::duplicate() const {
+    return SkNEW_ARGS(SkDWriteFontFileStream, (fFontFileStream.get()));
+}
+
+size_t SkDWriteFontFileStream::getPosition() const {
+    return fPos;
+}
+
+bool SkDWriteFontFileStream::seek(size_t position) {
+    size_t length = this->getLength();
+    fPos = (position > length) ? length : position;
+    return true;
+}
+
+bool SkDWriteFontFileStream::move(long offset) {
+    return seek(fPos + offset);
+}
+
+SkDWriteFontFileStream* SkDWriteFontFileStream::fork() const {
+    SkAutoTUnref<SkDWriteFontFileStream> that(this->duplicate());
+    that->seek(fPos);
+    return that.detach();
+}
+
+size_t SkDWriteFontFileStream::getLength() const {
+    HRESULT hr = S_OK;
+    UINT64 realFileSize = 0;
+    hr = fFontFileStream->GetFileSize(&realFileSize);
+    if (!SkTFitsIn<size_t>(realFileSize)) {
+        return 0;
+    }
+    return static_cast<size_t>(realFileSize);
+}
+
+const void* SkDWriteFontFileStream::getMemoryBase() {
+    if (fLockedMemory) {
+        return fLockedMemory;
+    }
+
+    UINT64 fileSize;
+    HRNM(fFontFileStream->GetFileSize(&fileSize), "Could not get file size");
+    HRNM(fFontFileStream->ReadFileFragment(&fLockedMemory, 0, fileSize, &fFragmentLock),
+         "Could not lock file fragment.");
+    return fLockedMemory;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+//  SkIDWriteFontFileStreamWrapper
+
+HRESULT SkDWriteFontFileStreamWrapper::Create(SkStream* stream, SkDWriteFontFileStreamWrapper** streamFontFileStream) {
+    *streamFontFileStream = new SkDWriteFontFileStreamWrapper(stream);
+    if (NULL == streamFontFileStream) {
+        return E_OUTOFMEMORY;
+    }
+    return S_OK;
+}
+
+SkDWriteFontFileStreamWrapper::SkDWriteFontFileStreamWrapper(SkStream* stream)
+    : fRefCount(1), fStream(SkRef(stream)) {
+}
+
+HRESULT STDMETHODCALLTYPE SkDWriteFontFileStreamWrapper::QueryInterface(REFIID iid, void** ppvObject) {
+    if (iid == IID_IUnknown || iid == __uuidof(IDWriteFontFileStream)) {
+        *ppvObject = this;
+        AddRef();
+        return S_OK;
+    } else {
+        *ppvObject = NULL;
+        return E_NOINTERFACE;
+    }
+}
+
+ULONG STDMETHODCALLTYPE SkDWriteFontFileStreamWrapper::AddRef() {
+    return InterlockedIncrement(&fRefCount);
+}
+
+ULONG STDMETHODCALLTYPE SkDWriteFontFileStreamWrapper::Release() {
+    ULONG newCount = InterlockedDecrement(&fRefCount);
+    if (0 == newCount) {
+        delete this;
+    }
+    return newCount;
+}
+
+HRESULT STDMETHODCALLTYPE SkDWriteFontFileStreamWrapper::ReadFileFragment(
+    void const** fragmentStart,
+    UINT64 fileOffset,
+    UINT64 fragmentSize,
+    void** fragmentContext)
+{
+    // The loader is responsible for doing a bounds check.
+    UINT64 fileSize;
+    this->GetFileSize(&fileSize);
+    if (fileOffset > fileSize || fragmentSize > fileSize - fileOffset) {
+        *fragmentStart = NULL;
+        *fragmentContext = NULL;
+        return E_FAIL;
+    }
+
+    if (!SkTFitsIn<size_t>(fileOffset + fragmentSize)) {
+        return E_FAIL;
+    }
+
+    const void* data = fStream->getMemoryBase();
+    if (NULL != data) {
+        *fragmentStart = static_cast<BYTE const*>(data) + static_cast<size_t>(fileOffset);
+        *fragmentContext = NULL;
+
+    } else {
+        //May be called from multiple threads.
+        SkAutoMutexAcquire ama(fStreamMutex);
+
+        *fragmentStart = NULL;
+        *fragmentContext = NULL;
+
+        if (!fStream->rewind()) {
+            return E_FAIL;
+        }
+        if (fStream->skip(static_cast<size_t>(fileOffset)) != fileOffset) {
+            return E_FAIL;
+        }
+        SkAutoTMalloc<uint8_t> streamData(static_cast<size_t>(fragmentSize));
+        if (fStream->read(streamData.get(), static_cast<size_t>(fragmentSize)) != fragmentSize) {
+            return E_FAIL;
+        }
+
+        *fragmentStart = streamData.get();
+        *fragmentContext = streamData.detach();
+    }
+    return S_OK;
+}
+
+void STDMETHODCALLTYPE SkDWriteFontFileStreamWrapper::ReleaseFileFragment(void* fragmentContext) {
+    sk_free(fragmentContext);
+}
+
+HRESULT STDMETHODCALLTYPE SkDWriteFontFileStreamWrapper::GetFileSize(UINT64* fileSize) {
+    *fileSize = fStream->getLength();
+    return S_OK;
+}
+
+HRESULT STDMETHODCALLTYPE SkDWriteFontFileStreamWrapper::GetLastWriteTime(UINT64* lastWriteTime) {
+    // The concept of last write time does not apply to this loader.
+    *lastWriteTime = 0;
+    return E_NOTIMPL;
+}