Revert "Remove all notion of transport from the API."

This reverts commit 4961a938586e3c46cf80f15ecb70a011324bfe59.

Reason for revert: Breaks MSVC

Original change's description:
> Remove all notion of transport from the API.
> 
> There is only a need to pass buffers in and out of the system.
> All transport is external to the system.
> 
> Change-Id: I26dfc8e0b4cce9969395c96d5230078e7dca3f3d
> Reviewed-on: https://skia-review.googlesource.com/119062
> Commit-Queue: Herb Derby <herb@google.com>
> Reviewed-by: Khushal Sagar <khushalsagar@google.com>

TBR=herb@google.com,reed@google.com,khushalsagar@google.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: I62cbac1be4483702ba7464822d93fb9f818f88b7
Reviewed-on: https://skia-review.googlesource.com/119580
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Herb Derby <herb@google.com>

3 files changed, 284 insertions, 200 deletions

diff --git a/src/core/SkRemoteGlyphCache.cpp b/src/core/SkRemoteGlyphCache.cpp
index 3d925c49d3..9a7557f5c4 100644
--- a/src/core/SkRemoteGlyphCache.cpp
+++ b/src/core/SkRemoteGlyphCache.cpp
@@ -43,6 +43,77 @@ private:
     size_t   fSize;
 };
 
+// -- SkRemoteStrikeTransport ----------------------------------------------------------------------
+
+static SkRemoteStrikeTransport::IOResult write_data(
+    size_t size, const uint8_t* data, SkRemoteStrikeTransport* t) {
+
+    if (t->write(&size, sizeof(size)) == SkRemoteStrikeTransport::kFail) {
+        return SkRemoteStrikeTransport::kFail;
+    }
+
+    if (t->write(data, size) == SkRemoteStrikeTransport::kFail) {
+        return SkRemoteStrikeTransport::kFail;
+    }
+
+    return SkRemoteStrikeTransport::kSuccess;
+}
+
+static SkRemoteStrikeTransport::IOResult read_data(
+    size_t size, uint8_t* data, SkRemoteStrikeTransport* t) {
+
+    size_t totalRead = 0;
+    while (totalRead < size) {
+        size_t sizeRead;
+        SkRemoteStrikeTransport::IOResult result;
+        std::tie(sizeRead, result) = t->read(&data[totalRead], size - totalRead);
+        if (result == SkRemoteStrikeTransport::kFail || sizeRead == 0) {
+            return SkRemoteStrikeTransport::kFail;
+        }
+        totalRead += sizeRead;
+    }
+
+    return SkRemoteStrikeTransport::kSuccess;
+}
+
+SkRemoteStrikeTransport::IOResult SkRemoteStrikeTransport::writeSkData(const SkData& data) {
+    return write_data(data.size(), (uint8_t*)data.data(), this);
+}
+
+sk_sp<SkData> SkRemoteStrikeTransport::readSkData() {
+    size_t size;
+    if(std::get<1>(this->read(&size, sizeof(size))) == kFail) {
+        return nullptr;
+    }
+
+    auto data = std::unique_ptr<uint8_t[]>{new uint8_t[size]};
+    if (read_data(size, data.get(), this) == kFail) {
+        return nullptr;
+    }
+
+    return SkData::MakeWithCopy(data.get(), size);
+}
+
+SkRemoteStrikeTransport::IOResult SkRemoteStrikeTransport::writeVector(
+    const std::vector<uint8_t>& vector) {
+    return write_data(vector.size(), vector.data(), this);
+}
+
+SkRemoteStrikeTransport::IOResult SkRemoteStrikeTransport::readVector(
+    std::vector<uint8_t>* vector) {
+    size_t vectorSize = 0;
+    size_t readSize = 0;
+    SkRemoteStrikeTransport::IOResult result;
+    std::tie(readSize, result) = this->read(&vectorSize, sizeof(vectorSize));
+    if(result == kFail || readSize == 0) {
+        return kFail;
+    }
+
+    vector->resize(vectorSize);
+
+    return read_data(vectorSize, vector->data(), this);
+}
+
 // -- Serializer ----------------------------------------------------------------------------------
 
 static size_t pad(size_t size, size_t alignment) {
@@ -91,20 +162,18 @@ private:
 
 class Deserializer {
 public:
-    Deserializer(const SkData& buffer) : fBuffer{buffer} { }
+    Deserializer(const std::vector<uint8_t>& buffer) : fBuffer{buffer} { }
 
     template <typename T>
     T* read() {
         size_t padded = pad(fCursor, alignof(T));
         fCursor = padded + sizeof(T);
-        auto data = (uint8_t*)fBuffer.data();
-        return (T*)&data[padded];
+        return (T*)&fBuffer[padded];
     }
 
     SkDescriptor* readDescriptor() {
         size_t padded = pad(fCursor, alignof(SkDescriptor));
-        auto data = (uint8_t*)fBuffer.data();
-        SkDescriptor* result = (SkDescriptor*)&data[padded];
+        SkDescriptor* result = (SkDescriptor*)&fBuffer[padded];
         fCursor = padded + result->getLength();
         return result;
     }
@@ -113,8 +182,7 @@ public:
     ArraySlice<T> readArray(int count) {
         size_t padded = pad(fCursor, alignof(T));
         size_t size = count * sizeof(T);
-        auto data = (uint8_t*)fBuffer.data();
-        const T* base = (const T*)&data[padded];
+        const T* base = (const T*)&fBuffer[padded];
         ArraySlice<T> result = ArraySlice<T>{base, (uint32_t)count};
         fCursor = padded + size;
         return result;
@@ -123,8 +191,8 @@ public:
     size_t size() {return fCursor;}
 
 private:
-    const SkData& fBuffer;
-    size_t        fCursor{0};
+    const std::vector<uint8_t>& fBuffer;
+    size_t                      fCursor{0};
 };
 
 
@@ -418,6 +486,14 @@ public:
     };
 };
 
+class Result {
+    union {
+        SkPaint::FontMetrics fontMetrics;
+        SkGlyph glyph;
+        StrikeDiffHeader strikeDiffHeader;
+    };
+};
+
 size_t SkStrikeCacheDifferenceSpec::sizeBytes() const {
     size_t sum = sizeof(Op) + sizeof(StrikeDiffHeader);
     for (auto& pair : fDescriptorToDifferencesMap) {
@@ -514,67 +590,85 @@ static void update_caches_from_strikes_data(SkStrikeClient *client,
 }
 
 // -- SkStrikeServer -------------------------------------------------------------------------------
-SkStrikeServer::SkStrikeServer() { }
+SkStrikeServer::SkStrikeServer(SkRemoteStrikeTransport* transport)
+    : fTransport{transport} { }
 
 SkStrikeServer::~SkStrikeServer() {
     printf("Strike server - ops: %d\n", fOpCount);
 }
 
-void SkStrikeServer::serve(const SkData& inBuffer, std::vector<uint8_t>* outBuffer) {
+int SkStrikeServer::serve() {
 
-    fOpCount += 1;
+    std::vector<uint8_t> inBuffer;
+    std::vector<uint8_t> outBuffer;
 
-    Serializer serializer{outBuffer};
-    Deserializer deserializer{inBuffer};
-    Op* op = deserializer.read<Op>();
-
-    switch (op->opCode) {
-        case OpCode::kFontMetrics : {
-            auto scaler = this->generateScalerContext(op->descriptor, op->typefaceId);
-            SkPaint::FontMetrics metrics;
-            scaler->getFontMetrics(&metrics);
-            serializer.push_back<SkPaint::FontMetrics>(metrics);
+    while (true) {
+        inBuffer.clear();
+        auto result = fTransport->readVector(&inBuffer);
+        if (result == SkRemoteStrikeTransport::kFail) {
             break;
         }
-        case OpCode::kGlyphPath : {
-            auto sc = this->generateScalerContext(op->descriptor, op->typefaceId);
-            // TODO: check for buffer overflow.
-            SkPath path;
-            if (sc->getPath(op->glyphID, &path)) {
-                size_t pathSize = path.writeToMemory(nullptr);
-                serializer.push_back<size_t>(pathSize);
-                auto pathData = serializer.allocateArray<uint8_t>(pathSize);
-                path.writeToMemory(pathData);
-            }
-            break;
-        }
-        case OpCode::kGlyphMetricsAndImage : {
-            auto scaler = this->generateScalerContext(op->descriptor, op->typefaceId);
 
-            auto glyph = serializer.emplace_back<SkGlyph>();
-            // TODO: check for buffer overflow.
-            glyph->initWithGlyphID(op->glyphID);
-            scaler->getMetrics(glyph);
-            auto imageSize = glyph->computeImageSize();
-            glyph->fPathData = nullptr;
-            glyph->fImage = nullptr;
-            if (imageSize > 0) {
-                // Since the allocateArray can move glyph, make one that stays in one place.
-                SkGlyph stationaryGlyph = *glyph;
-                stationaryGlyph.fImage = serializer.allocateArray<uint8_t>(imageSize);
-                scaler->getImage(stationaryGlyph);
+        Deserializer deserializer{inBuffer};
+        Op* op = deserializer.read<Op>();
+
+        fOpCount += 1;
+
+        outBuffer.clear();
+        Serializer serializer{&outBuffer};
+
+        switch (op->opCode) {
+            case OpCode::kFontMetrics : {
+                auto sc = this->generateScalerContext(op->descriptor, op->typefaceId);
+                SkPaint::FontMetrics metrics;
+                sc->getFontMetrics(&metrics);
+                serializer.push_back<SkPaint::FontMetrics>(metrics);
+                break;
             }
-            break;
-        }
-        case OpCode::kPrepopulateCache : {
-            read_strikes_spec_write_strikes_data(
-                    &deserializer, &serializer, this);
-            break;
+            case OpCode::kGlyphPath : {
+                auto sc = this->generateScalerContext(op->descriptor, op->typefaceId);
+                // TODO: check for buffer overflow.
+                SkPath path;
+                if (sc->getPath(op->glyphID, &path)) {
+                    size_t pathSize = path.writeToMemory(nullptr);
+                    serializer.push_back<size_t>(pathSize);
+                    auto pathData = serializer.allocateArray<uint8_t>(pathSize);
+                    path.writeToMemory(pathData);
+                }
+                break;
+            }
+            case OpCode::kGlyphMetricsAndImage : {
+                auto scaler = this->generateScalerContext(op->descriptor, op->typefaceId);
+
+                auto glyph = serializer.emplace_back<SkGlyph>();
+                // TODO: check for buffer overflow.
+                glyph->initWithGlyphID(op->glyphID);
+                scaler->getMetrics(glyph);
+                auto imageSize = glyph->computeImageSize();
+                glyph->fPathData = nullptr;
+                glyph->fImage = nullptr;
+
+                if (imageSize > 0) {
+                    // Since the allocateArray can move glyph, make one that stays in one place.
+                    SkGlyph stationaryGlyph = *glyph;
+                    stationaryGlyph.fImage = serializer.allocateArray<uint8_t>(imageSize);
+                    scaler->getImage(stationaryGlyph);
+                }
+                break;
+            }
+            case OpCode::kPrepopulateCache : {
+                read_strikes_spec_write_strikes_data(
+                        &deserializer, &serializer, this);
+                break;
+            }
+
+            default:
+                SK_ABORT("Bad op");
         }
 
-        default:
-            SK_ABORT("Bad op");
+        fTransport->writeVector(outBuffer);
     }
+    return 0;
 }
 
 void SkStrikeServer::prepareSerializeProcs(SkSerialProcs* procs) {
@@ -623,88 +717,105 @@ sk_sp<SkData> SkStrikeServer::encodeTypeface(SkTypeface* tf) {
 }
 
 // -- SkStrikeClient -------------------------------------------------------------------------------
-SkStrikeClient::SkStrikeClient(SkStrikeCacheClientRPC clientRPC)
-    : fClientRPC{clientRPC} { }
 
-void SkStrikeClient::generateFontMetrics(
-    const SkTypefaceProxy& typefaceProxy,
-    const SkScalerContextRec& rec,
-    SkPaint::FontMetrics* metrics)
-{
-    fBuffer.clear();
+SkStrikeClient::SkStrikeClient(SkRemoteStrikeTransport* transport)
+    : fTransport{transport} { }
 
-    Serializer serializer{&fBuffer};
-    serializer.emplace_back<Op>(OpCode::kFontMetrics, typefaceProxy.remoteTypefaceID(), rec);
+void SkStrikeClient::generateFontMetrics(
+        const SkTypefaceProxy& typefaceProxy,
+        const SkScalerContextRec& rec,
+        SkPaint::FontMetrics* metrics) {
+    // Send generateFontMetrics
+    {
+        fBuffer.clear();
+        Serializer serializer{&fBuffer};
+        serializer.emplace_back<Op>(OpCode::kFontMetrics, typefaceProxy.remoteTypefaceID(), rec);
+        fTransport->writeVector(fBuffer);
+    }
 
-    auto outBuffer = SkData::MakeWithoutCopy(fBuffer.data(), fBuffer.size());
-    auto inbuffer = fClientRPC(*outBuffer);
-    Deserializer deserializer(*inbuffer);
-    *metrics = *deserializer.read<SkPaint::FontMetrics>();
+    // Receive generateFontMetrics
+    {
+        fBuffer.clear();
+        fTransport->readVector(&fBuffer);
+        Deserializer deserializer(fBuffer);
+        *metrics = *deserializer.read<SkPaint::FontMetrics>();
+    }
 }
 
 void SkStrikeClient::generateMetricsAndImage(
-    const SkTypefaceProxy& typefaceProxy,
-    const SkScalerContextRec& rec,
-    SkArenaAlloc* alloc,
-    SkGlyph* glyph)
-{
+        const SkTypefaceProxy& typefaceProxy,
+        const SkScalerContextRec& rec,
+        SkArenaAlloc* alloc,
+        SkGlyph* glyph) {
+    {
         fBuffer.clear();
         Serializer serializer(&fBuffer);
         Op *op = serializer.emplace_back<Op>(
             OpCode::kGlyphMetricsAndImage, typefaceProxy.remoteTypefaceID(), rec);
-    op->glyphID = glyph->getPackedID();
-
-    auto outBuffer = SkData::MakeWithoutCopy(fBuffer.data(), fBuffer.size());
-    auto inbuffer = fClientRPC(*outBuffer);
-    Deserializer deserializer(*inbuffer);
-    *glyph = *deserializer.read<SkGlyph>();
-    auto imageSize = glyph->computeImageSize();
-    glyph->fPathData = nullptr;
-    glyph->fImage    = nullptr;
-    if (imageSize > 0) {
-        auto image = deserializer.readArray<uint8_t>(imageSize);
-        SkASSERT(imageSize == image.size());
-        glyph->allocImage(alloc);
-        memcpy(glyph->fImage, image.data(), imageSize);
+        op->glyphID = glyph->getPackedID();
+        fTransport->writeVector(fBuffer);
+    }
+
+    // Receive generateMetricsAndImage
+    {
+        fBuffer.clear();
+        fTransport->readVector(&fBuffer);
+        Deserializer deserializer(fBuffer);
+        *glyph = *deserializer.read<SkGlyph>();
+        auto imageSize = glyph->computeImageSize();
+        glyph->fPathData = nullptr;
+        glyph->fImage    = nullptr;
+        if (imageSize > 0) {
+            auto image = deserializer.readArray<uint8_t>(imageSize);
+            SkASSERT(imageSize == image.size());
+            glyph->allocImage(alloc);
+            memcpy(glyph->fImage, image.data(), imageSize);
+        }
     }
-}
 
+}
 bool SkStrikeClient::generatePath(
-    const SkTypefaceProxy& typefaceProxy,
-    const SkScalerContextRec& rec,
-    SkGlyphID glyphID,
-    SkPath* path)
-{
-    fBuffer.clear();
-
-    Serializer serializer{&fBuffer};
-    Op *op = serializer.emplace_back<Op>(
-        OpCode::kGlyphPath, typefaceProxy.remoteTypefaceID(), rec);
-    op->glyphID = glyphID;
-
-    auto outBuffer = SkData::MakeWithoutCopy(fBuffer.data(), fBuffer.size());
-    auto inbuffer = fClientRPC(*outBuffer);
-    Deserializer deserializer(*inbuffer);
-    size_t pathSize = *deserializer.read<size_t>();
-    if (pathSize == 0) {
-        return false;
+        const SkTypefaceProxy& typefaceProxy,
+        const SkScalerContextRec& rec,
+        SkGlyphID glyphID,
+        SkPath* path) {
+    {
+        fBuffer.clear();
+        Serializer serializer{&fBuffer};
+        Op *op = serializer.emplace_back<Op>(
+            OpCode::kGlyphPath, typefaceProxy.remoteTypefaceID(), rec);
+        op->glyphID = glyphID;
+        fTransport->writeVector(fBuffer);
+    }
+
+    {
+        fBuffer.clear();
+        fTransport->readVector(&fBuffer);
+        Deserializer deserializer{fBuffer};
+        size_t pathSize = *deserializer.read<size_t>();
+        if (pathSize == 0) {
+            return false;
+        }
+        auto rawPath = deserializer.readArray<uint8_t>(pathSize);
+        path->readFromMemory(rawPath.data(), rawPath.size());
     }
-    auto rawPath = deserializer.readArray<uint8_t>(pathSize);
-    path->readFromMemory(rawPath.data(), rawPath.size());
     return true;
 }
 
 void SkStrikeClient::primeStrikeCache(const SkStrikeCacheDifferenceSpec& strikeDifferences) {
-    fBuffer.clear();
-    fBuffer.reserve(strikeDifferences.sizeBytes());
-
-    Serializer serializer{&fBuffer};
-    write_strikes_spec(strikeDifferences, &serializer);
-
-    auto outBuffer = SkData::MakeWithoutCopy(fBuffer.data(), fBuffer.size());
-    auto inbuffer = fClientRPC(*outBuffer);
-    Deserializer deserializer(*inbuffer);
-    update_caches_from_strikes_data(this, &deserializer);
+    {
+        fBuffer.clear();
+        fBuffer.reserve(strikeDifferences.sizeBytes());
+        Serializer serializer{&fBuffer};
+        write_strikes_spec(strikeDifferences, &serializer);
+        fTransport->writeVector(fBuffer);
+    }
+    {
+        fBuffer.clear();
+        fTransport->readVector(&fBuffer);
+        Deserializer deserializer{fBuffer};
+        update_caches_from_strikes_data(this, &deserializer);
+    }
 }
 
 void SkStrikeClient::prepareDeserializeProcs(SkDeserialProcs* procs) {
diff --git a/src/core/SkRemoteGlyphCache.h b/src/core/SkRemoteGlyphCache.h
index 04d72a083b..3dfa8c28e5 100644
--- a/src/core/SkRemoteGlyphCache.h
+++ b/src/core/SkRemoteGlyphCache.h
@@ -19,15 +19,26 @@
 #include "SkGlyphCache.h"
 #include "SkMakeUnique.h"
 #include "SkNoDrawCanvas.h"
-#include "SkRefCnt.h"
 #include "SkSerialProcs.h"
 #include "SkTextBlobRunIterator.h"
 #include "SkTHash.h"
 #include "SkTypeface.h"
 #include "SkTypeface_remote.h"
 
-// The client uses a SkStrikeCacheClientRPC to send and receive data.
-using SkStrikeCacheClientRPC = std::function<sk_sp<SkData>(const SkData&)>;
+class SkScalerContextRecDescriptor;
+
+class SkRemoteStrikeTransport {
+public:
+    enum IOResult : bool {kFail = false, kSuccess = true};
+
+    virtual ~SkRemoteStrikeTransport() {}
+    virtual IOResult write(const void*, size_t) = 0;
+    virtual std::tuple<size_t, IOResult> read(void*, size_t) = 0;
+    IOResult writeSkData(const SkData&);
+    sk_sp<SkData> readSkData();
+    IOResult writeVector(const std::vector<uint8_t>&);
+    IOResult readVector(std::vector<uint8_t>*);
+};
 
 class SkScalerContextRecDescriptor {
 public:
@@ -83,7 +94,7 @@ private:
     } fDescriptor;
 };
 
-class SK_API SkStrikeCacheDifferenceSpec {
+class SkStrikeCacheDifferenceSpec {
     class StrikeDifferences;
 
 public:
@@ -120,7 +131,7 @@ private:
     DescMap fDescriptorToDifferencesMap{16, DescHash(), DescEq()};
 };
 
-class SK_API SkTextBlobCacheDiffCanvas : public SkNoDrawCanvas {
+class SkTextBlobCacheDiffCanvas : public SkNoDrawCanvas {
 public:
     SkTextBlobCacheDiffCanvas(int width, int height,
                               const SkMatrix& deviceMatrix,
@@ -153,14 +164,13 @@ private:
     SkStrikeCacheDifferenceSpec* const fStrikeCacheDiff;
 };
 
-class SK_API SkStrikeServer {
+class SkStrikeServer {
 public:
-    SkStrikeServer();
+    SkStrikeServer(SkRemoteStrikeTransport* transport);
     ~SkStrikeServer();
 
     // embedding clients call these methods
-    void serve(const SkData&, std::vector<uint8_t>*);
-
+    int serve();  // very negotiable
     void prepareSerializeProcs(SkSerialProcs* procs);
 
     // mostly called internally by Skia
@@ -175,13 +185,14 @@ private:
     sk_sp<SkData> encodeTypeface(SkTypeface* tf);
 
     int fOpCount = 0;
+    SkRemoteStrikeTransport* const fTransport;
     SkTHashMap<SkFontID, sk_sp<SkTypeface>> fTypefaceMap;
     DescriptorToContextMap fScalerContextMap;
 };
 
-class SK_API SkStrikeClient {
+class SkStrikeClient {
 public:
-    SkStrikeClient(SkStrikeCacheClientRPC);
+    SkStrikeClient(SkRemoteStrikeTransport*);
 
     // embedding clients call these methods
     void primeStrikeCache(const SkStrikeCacheDifferenceSpec&);
@@ -202,7 +213,7 @@ private:
     // TODO: Figure out how to manage the entries for the following maps.
     SkTHashMap<SkFontID, sk_sp<SkTypefaceProxy>> fMapIdToTypeface;
 
-    SkStrikeCacheClientRPC fClientRPC;
+    SkRemoteStrikeTransport* const fTransport;
 
     std::vector<uint8_t> fBuffer;
 };
diff --git a/tools/remote_demo.cpp b/tools/remote_demo.cpp
index 8fc96cadb8..a5e0a367de 100644
--- a/tools/remote_demo.cpp
+++ b/tools/remote_demo.cpp
@@ -25,52 +25,35 @@ static bool gUseGpu = true;
 static bool gPurgeFontCaches = true;
 static bool gUseProcess = true;
 
-static bool write_SkData(int fd, const SkData& data) {
-    size_t size = data.size();
-    ssize_t bytesWritten = ::write(fd, &size, sizeof(size));
-    if (bytesWritten < 0) {
-        err(1,"Failed write %zu", size);
-        return false;
-    }
-
-    bytesWritten = ::write(fd, data.data(), data.size());
-    if (bytesWritten < 0) {
-        err(1,"Failed write %zu", size);
-        return false;
+class ReadWriteTransport : public SkRemoteStrikeTransport {
+public:
+    ReadWriteTransport(int readFd, int writeFd) : fReadFd{readFd}, fWriteFd{writeFd} {}
+    ~ReadWriteTransport() override {
+        close(fWriteFd);
+        close(fReadFd);
     }
-
-    return true;
-}
-
-static sk_sp<SkData> read_SkData(int fd) {
-
-    size_t size;
-    ssize_t readSize = ::read(fd, &size, sizeof(size));
-    if (readSize <= 0) {
-        if (readSize < 0) {
-            err(1, "Failed read %zu", size);
+    IOResult write(const void* buffer, size_t size) override {
+        ssize_t writeSize = ::write(fWriteFd, buffer, size);
+        if (writeSize < 0) {
+            err(1,"Failed write %zu", size);
+            return kFail;
         }
-        return nullptr;
+        return kSuccess;
     }
 
-    auto out = SkData::MakeUninitialized(size);
-    auto data = (uint8_t*)out->data();
-
-    size_t totalRead = 0;
-    while (totalRead < size) {
-        ssize_t sizeRead;
-        sizeRead = ::read(fd, &data[totalRead], size - totalRead);
-        if (sizeRead <= 0) {
-            if (readSize < 0) {
-                err(1, "Failed read %zu", size);
-            }
-            return nullptr;
+    std::tuple<size_t, IOResult> read(void* buffer, size_t size) override {
+        ssize_t readSize = ::read(fReadFd, buffer, size);
+        if (readSize < 0) {
+            err(1,"Failed read %zu", size);
+            return {size, kFail};
         }
-        totalRead += sizeRead;
+        return {readSize, kSuccess};
     }
 
-    return out;
-}
+private:
+    const int fReadFd,
+              fWriteFd;
+};
 
 class Timer {
 public:
@@ -150,17 +133,14 @@ static void final_draw(std::string outFilename,
 static void gpu(int readFd, int writeFd) {
 
     if (gUseGpu) {
-        auto clientRPC = [readFd, writeFd](const SkData& inBuffer) {
-            write_SkData(writeFd, inBuffer);
-            return read_SkData(readFd);
-        };
+        ReadWriteTransport rwTransport{readFd, writeFd};
 
-        auto picData = read_SkData(readFd);
+        auto picData = rwTransport.readSkData();
         if (picData == nullptr) {
             return;
         }
 
-        SkStrikeClient client{clientRPC};
+        SkStrikeClient client{&rwTransport};
 
         SkDeserialProcs procs;
         client.prepareDeserializeProcs(&procs);
@@ -168,20 +148,14 @@ static void gpu(int readFd, int writeFd) {
         final_draw("test.png", &procs, picData.get(), &client);
     }
 
-    ::close(writeFd);
-    ::close(readFd);
-
     printf("GPU is exiting\n");
 }
 
 static int renderer(
     const std::string& skpName, int readFd, int writeFd)
 {
-    SkStrikeServer server{};
-    auto closeAll = [readFd, writeFd]() {
-        ::close(writeFd);
-        ::close(readFd);
-    };
+    ReadWriteTransport rwTransport{readFd, writeFd};
+    SkStrikeServer server{&rwTransport};
 
     auto skpData = SkData::MakeFromFileName(skpName.c_str());
     std::cout << "skp stream is " << skpData->size() << " bytes long " << std::endl;
@@ -193,28 +167,16 @@ static int renderer(
         server.prepareSerializeProcs(&procs);
         stream = pic->serialize(&procs);
 
-        if (!write_SkData(writeFd, *stream)) {
-            closeAll();
+        if (rwTransport.writeSkData(*stream) == SkRemoteStrikeTransport::kFail) {
             return 1;
         }
 
-        std::vector<uint8_t> tmpBuffer;
-        while (true) {
-            auto inBuffer = read_SkData(readFd);
-            if (inBuffer == nullptr) {
-                closeAll();
-                return 0;
-            }
+        std::cout << "Waiting for scaler context ops." << std::endl;
 
-            tmpBuffer.clear();
-            server.serve(*inBuffer, &tmpBuffer);
-            auto outBuffer = SkData::MakeWithoutCopy(tmpBuffer.data(), tmpBuffer.size());
-            write_SkData(writeFd, *outBuffer);
-        }
+        return server.serve();
     } else {
         stream = skpData;
         final_draw("test-correct.png", nullptr, stream.get(), nullptr);
-        closeAll();
         return 0;
     }
 }