Make Flattenable not virtual

Fallout from the Flattenable change, update all its uses.

Additionnaly, fix/tighten size checks when (un)flatten()ing
things.

Removed the assumption by some flattenables (e.g.: Fence)
that the size passed to them would be exact (it can
and will be larger in some cases)

The code in Parcel is a bit complicated so that we don't
have to expose the full implementation (and also to
keep the code smallish).

Change-Id: I0bf1c8aca2a3128491b4f45510bc46667e566dde
diff --git a/libs/binder/Parcel.cpp b/libs/binder/Parcel.cpp
index 359742c..7a5919f 100644
--- a/libs/binder/Parcel.cpp
+++ b/libs/binder/Parcel.cpp
@@ -798,13 +798,13 @@
     return status;
 }
 
-status_t Parcel::write(const Flattenable& val)
+status_t Parcel::write(const FlattenableHelperInterface& val)
 {
     status_t err;
 
     // size if needed
-    size_t len = val.getFlattenedSize();
-    size_t fd_count = val.getFdCount();
+    const size_t len = val.getFlattenedSize();
+    const size_t fd_count = val.getFdCount();
 
     err = this->writeInt32(len);
     if (err) return err;
@@ -813,7 +813,7 @@
     if (err) return err;
 
     // payload
-    void* buf = this->writeInplace(PAD_SIZE(len));
+    void* const buf = this->writeInplace(PAD_SIZE(len));
     if (buf == NULL)
         return BAD_VALUE;
 
@@ -1174,14 +1174,14 @@
     return NO_ERROR;
 }
 
-status_t Parcel::read(Flattenable& val) const
+status_t Parcel::read(FlattenableHelperInterface& val) const
 {
     // size
     const size_t len = this->readInt32();
     const size_t fd_count = this->readInt32();
 
     // payload
-    void const* buf = this->readInplace(PAD_SIZE(len));
+    void const* const buf = this->readInplace(PAD_SIZE(len));
     if (buf == NULL)
         return BAD_VALUE;
 
diff --git a/libs/gui/IGraphicBufferProducer.cpp b/libs/gui/IGraphicBufferProducer.cpp
index 2e561df..48b2870 100644
--- a/libs/gui/IGraphicBufferProducer.cpp
+++ b/libs/gui/IGraphicBufferProducer.cpp
@@ -270,8 +270,7 @@
     parcel.read(*this);
 }
 
-size_t IGraphicBufferProducer::QueueBufferInput::getFlattenedSize() const
-{
+size_t IGraphicBufferProducer::QueueBufferInput::getFlattenedSize() const {
     return sizeof(timestamp)
          + sizeof(crop)
          + sizeof(scalingMode)
@@ -280,38 +279,46 @@
          + fence->getFlattenedSize();
 }
 
-size_t IGraphicBufferProducer::QueueBufferInput::getFdCount() const
-{
+size_t IGraphicBufferProducer::QueueBufferInput::getFdCount() const {
     return fence->getFdCount();
 }
 
-status_t IGraphicBufferProducer::QueueBufferInput::flatten(void* buffer, size_t size,
-        int fds[], size_t count) const
+status_t IGraphicBufferProducer::QueueBufferInput::flatten(
+        void*& buffer, size_t& size, int*& fds, size_t& count) const
 {
-    status_t err = NO_ERROR;
-    char* p = (char*)buffer;
-    memcpy(p, &timestamp,   sizeof(timestamp));   p += sizeof(timestamp);
-    memcpy(p, &crop,        sizeof(crop));        p += sizeof(crop);
-    memcpy(p, &scalingMode, sizeof(scalingMode)); p += sizeof(scalingMode);
-    memcpy(p, &transform,   sizeof(transform));   p += sizeof(transform);
-    memcpy(p, &async,       sizeof(async));       p += sizeof(async);
-    err = fence->flatten(p, size - (p - (char*)buffer), fds, count);
-    return err;
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
+    FlattenableUtils::write(buffer, size, timestamp);
+    FlattenableUtils::write(buffer, size, crop);
+    FlattenableUtils::write(buffer, size, scalingMode);
+    FlattenableUtils::write(buffer, size, transform);
+    FlattenableUtils::write(buffer, size, async);
+    return fence->flatten(buffer, size, fds, count);
 }
 
-status_t IGraphicBufferProducer::QueueBufferInput::unflatten(void const* buffer,
-        size_t size, int fds[], size_t count)
+status_t IGraphicBufferProducer::QueueBufferInput::unflatten(
+        void const*& buffer, size_t& size, int const*& fds, size_t& count)
 {
-    status_t err = NO_ERROR;
-    const char* p = (const char*)buffer;
-    memcpy(&timestamp,   p, sizeof(timestamp));   p += sizeof(timestamp);
-    memcpy(&crop,        p, sizeof(crop));        p += sizeof(crop);
-    memcpy(&scalingMode, p, sizeof(scalingMode)); p += sizeof(scalingMode);
-    memcpy(&transform,   p, sizeof(transform));   p += sizeof(transform);
-    memcpy(&async,       p, sizeof(async));       p += sizeof(async);
+    size_t minNeeded =
+              sizeof(timestamp)
+            + sizeof(crop)
+            + sizeof(scalingMode)
+            + sizeof(transform)
+            + sizeof(async);
+
+    if (size < minNeeded) {
+        return NO_MEMORY;
+    }
+
+    FlattenableUtils::read(buffer, size, timestamp);
+    FlattenableUtils::read(buffer, size, crop);
+    FlattenableUtils::read(buffer, size, scalingMode);
+    FlattenableUtils::read(buffer, size, transform);
+    FlattenableUtils::read(buffer, size, async);
+
     fence = new Fence();
-    err = fence->unflatten(p, size - (p - (const char*)buffer), fds, count);
-    return err;
+    return fence->unflatten(buffer, size, fds, count);
 }
 
 }; // namespace android
diff --git a/libs/gui/Sensor.cpp b/libs/gui/Sensor.cpp
index c52a88f..d84c370 100644
--- a/libs/gui/Sensor.cpp
+++ b/libs/gui/Sensor.cpp
@@ -98,85 +98,85 @@
     return mVersion;
 }
 
-size_t Sensor::getSize() const
+size_t Sensor::getFlattenedSize() const
 {
-    return  sizeof(int32_t) + ((mName.length() + 3) & ~3) +
-            sizeof(int32_t) + ((mVendor.length() + 3) & ~3) +
+    size_t fixedSize =
             sizeof(int32_t) * 3 +
             sizeof(float) * 4 +
             sizeof(int32_t);
+
+    size_t variableSize =
+            sizeof(int32_t) + FlattenableUtils::align<4>(mName.length()) +
+            sizeof(int32_t) + FlattenableUtils::align<4>(mVendor.length());
+
+    return fixedSize + variableSize;
 }
 
-static inline
-size_t write(void* buffer, size_t offset, const String8& value) {
-    memcpy(static_cast<char*>(buffer) + offset, value.string(), value.length());
-    return (value.length() + 3) & ~3;
-}
+status_t Sensor::flatten(void* buffer, size_t size) const {
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
 
-static inline
-size_t write(void* buffer, size_t offset, float value) {
-    *reinterpret_cast<float*>(static_cast<char*>(buffer) + offset) = value;
-    return sizeof(float);
-}
+    FlattenableUtils::write(buffer, size, mName.length());
+    memcpy(static_cast<char*>(buffer), mName.string(), mName.length());
+    FlattenableUtils::advance(buffer, size, FlattenableUtils::align<4>(mName.length()));
 
-static inline
-size_t write(void* buffer, size_t offset, int32_t value) {
-    *reinterpret_cast<int32_t*>(static_cast<char*>(buffer) + offset) = value;
-    return sizeof(int32_t);
-}
+    FlattenableUtils::write(buffer, size, mVendor.length());
+    memcpy(static_cast<char*>(buffer), mVendor.string(), mVendor.length());
+    FlattenableUtils::advance(buffer, size, FlattenableUtils::align<4>(mVendor.length()));
 
-status_t Sensor::flatten(void* buffer) const
-{
-    size_t offset = 0;
-    offset += write(buffer, offset, int32_t(mName.length()));
-    offset += write(buffer, offset, mName);
-    offset += write(buffer, offset, int32_t(mVendor.length()));
-    offset += write(buffer, offset, mVendor);
-    offset += write(buffer, offset, mVersion);
-    offset += write(buffer, offset, mHandle);
-    offset += write(buffer, offset, mType);
-    offset += write(buffer, offset, mMinValue);
-    offset += write(buffer, offset, mMaxValue);
-    offset += write(buffer, offset, mResolution);
-    offset += write(buffer, offset, mPower);
-    offset += write(buffer, offset, mMinDelay);
+    FlattenableUtils::write(buffer, size, mVersion);
+    FlattenableUtils::write(buffer, size, mHandle);
+    FlattenableUtils::write(buffer, size, mType);
+    FlattenableUtils::write(buffer, size, mMinValue);
+    FlattenableUtils::write(buffer, size, mMaxValue);
+    FlattenableUtils::write(buffer, size, mResolution);
+    FlattenableUtils::write(buffer, size, mPower);
+    FlattenableUtils::write(buffer, size, mMinDelay);
     return NO_ERROR;
 }
 
-static inline
-size_t read(void const* buffer, size_t offset, String8* value, int32_t len) {
-    value->setTo(static_cast<char const*>(buffer) + offset, len);
-    return (len + 3) & ~3;
-}
+status_t Sensor::unflatten(void const* buffer, size_t size) {
+    size_t len;
 
-static inline
-size_t read(void const* buffer, size_t offset, float* value) {
-    *value = *reinterpret_cast<float const*>(static_cast<char const*>(buffer) + offset);
-    return sizeof(float);
-}
+    if (size < sizeof(size_t)) {
+        return NO_MEMORY;
+    }
+    FlattenableUtils::read(buffer, size, len);
+    if (size < len) {
+        return NO_MEMORY;
+    }
+    mName.setTo(static_cast<char const*>(buffer), len);
+    FlattenableUtils::advance(buffer, size, FlattenableUtils::align<4>(len));
 
-static inline
-size_t read(void const* buffer, size_t offset, int32_t* value) {
-    *value = *reinterpret_cast<int32_t const*>(static_cast<char const*>(buffer) + offset);
-    return sizeof(int32_t);
-}
 
-status_t Sensor::unflatten(void const* buffer, size_t size)
-{
-    int32_t len;
-    size_t offset = 0;
-    offset += read(buffer, offset, &len);
-    offset += read(buffer, offset, &mName, len);
-    offset += read(buffer, offset, &len);
-    offset += read(buffer, offset, &mVendor, len);
-    offset += read(buffer, offset, &mVersion);
-    offset += read(buffer, offset, &mHandle);
-    offset += read(buffer, offset, &mType);
-    offset += read(buffer, offset, &mMinValue);
-    offset += read(buffer, offset, &mMaxValue);
-    offset += read(buffer, offset, &mResolution);
-    offset += read(buffer, offset, &mPower);
-    offset += read(buffer, offset, &mMinDelay);
+    if (size < sizeof(size_t)) {
+        return NO_MEMORY;
+    }
+    FlattenableUtils::read(buffer, size, len);
+    if (size < len) {
+        return NO_MEMORY;
+    }
+    mVendor.setTo(static_cast<char const*>(buffer), len);
+    FlattenableUtils::advance(buffer, size, FlattenableUtils::align<4>(len));
+
+    size_t fixedSize =
+            sizeof(int32_t) * 3 +
+            sizeof(float) * 4 +
+            sizeof(int32_t);
+
+    if (size < fixedSize) {
+        return NO_MEMORY;
+    }
+
+    FlattenableUtils::read(buffer, size, mVersion);
+    FlattenableUtils::read(buffer, size, mHandle);
+    FlattenableUtils::read(buffer, size, mType);
+    FlattenableUtils::read(buffer, size, mMinValue);
+    FlattenableUtils::read(buffer, size, mMaxValue);
+    FlattenableUtils::read(buffer, size, mResolution);
+    FlattenableUtils::read(buffer, size, mPower);
+    FlattenableUtils::read(buffer, size, mMinDelay);
     return NO_ERROR;
 }
 
diff --git a/libs/ui/Fence.cpp b/libs/ui/Fence.cpp
index 464ee86..93ec0ce 100644
--- a/libs/ui/Fence.cpp
+++ b/libs/ui/Fence.cpp
@@ -127,37 +127,49 @@
 }
 
 size_t Fence::getFlattenedSize() const {
-    return 0;
+    return 1;
 }
 
 size_t Fence::getFdCount() const {
     return isValid() ? 1 : 0;
 }
 
-status_t Fence::flatten(void* buffer, size_t size, int fds[],
-        size_t count) const {
-    if (size != getFlattenedSize() || count != getFdCount()) {
-        return BAD_VALUE;
+status_t Fence::flatten(void*& buffer, size_t& size, int*& fds, size_t& count) const {
+    if (size < getFlattenedSize() || count < getFdCount()) {
+        return NO_MEMORY;
     }
-
+    FlattenableUtils::write(buffer, size, getFdCount());
     if (isValid()) {
-        fds[0] = mFenceFd;
+        *fds++ = mFenceFd;
+        count--;
     }
     return NO_ERROR;
 }
 
-status_t Fence::unflatten(void const* buffer, size_t size, int fds[],
-        size_t count) {
-    if (size != 0 || (count != 0 && count != 1)) {
-        return BAD_VALUE;
-    }
+status_t Fence::unflatten(void const*& buffer, size_t& size, int const*& fds, size_t& count) {
     if (mFenceFd != -1) {
         // Don't unflatten if we already have a valid fd.
         return INVALID_OPERATION;
     }
 
-    if (count == 1) {
-        mFenceFd = fds[0];
+    if (size < 1) {
+        return NO_MEMORY;
+    }
+
+    size_t numFds;
+    FlattenableUtils::read(buffer, size, numFds);
+
+    if (numFds > 1) {
+        return BAD_VALUE;
+    }
+
+    if (count < numFds) {
+        return NO_MEMORY;
+    }
+
+    if (numFds) {
+        mFenceFd = *fds++;
+        count--;
     }
 
     return NO_ERROR;
diff --git a/libs/ui/GraphicBuffer.cpp b/libs/ui/GraphicBuffer.cpp
index 580788d..1f273e2 100644
--- a/libs/ui/GraphicBuffer.cpp
+++ b/libs/ui/GraphicBuffer.cpp
@@ -209,9 +209,7 @@
     return handle ? handle->numFds : 0;
 }
 
-status_t GraphicBuffer::flatten(void* buffer, size_t size,
-        int fds[], size_t count) const
-{
+status_t GraphicBuffer::flatten(void*& buffer, size_t& size, int*& fds, size_t& count) const {
     size_t sizeNeeded = GraphicBuffer::getFlattenedSize();
     if (size < sizeNeeded) return NO_MEMORY;
 
@@ -236,12 +234,16 @@
         memcpy(&buf[8], h->data + h->numFds, h->numInts*sizeof(int));
     }
 
+    buffer = reinterpret_cast<void*>(static_cast<int*>(buffer) + sizeNeeded);
+    size -= sizeNeeded;
+    fds += handle->numFds;
+    count -= handle->numFds;
+
     return NO_ERROR;
 }
 
-status_t GraphicBuffer::unflatten(void const* buffer, size_t size,
-        int fds[], size_t count)
-{
+status_t GraphicBuffer::unflatten(
+        void const*& buffer, size_t& size, int const*& fds, size_t& count) {
     if (size < 8*sizeof(int)) return NO_MEMORY;
 
     int const* buf = static_cast<int const*>(buffer);
@@ -287,6 +289,11 @@
         }
     }
 
+    buffer = reinterpret_cast<void const*>(static_cast<int const*>(buffer) + sizeNeeded);
+    size -= sizeNeeded;
+    fds += numFds;
+    count -= numFds;
+
     return NO_ERROR;
 }
 
diff --git a/libs/ui/Region.cpp b/libs/ui/Region.cpp
index 623f8ed..e5abcf5 100644
--- a/libs/ui/Region.cpp
+++ b/libs/ui/Region.cpp
@@ -715,14 +715,17 @@
 
 // ----------------------------------------------------------------------------
 
-size_t Region::getSize() const {
+size_t Region::getFlattenedSize() const {
     return mStorage.size() * sizeof(Rect);
 }
 
-status_t Region::flatten(void* buffer) const {
+status_t Region::flatten(void* buffer, size_t size) const {
 #if VALIDATE_REGIONS
     validate(*this, "Region::flatten");
 #endif
+    if (size < mStorage.size() * sizeof(Rect)) {
+        return NO_MEMORY;
+    }
     Rect* rects = reinterpret_cast<Rect*>(buffer);
     memcpy(rects, mStorage.array(), mStorage.size() * sizeof(Rect));
     return NO_ERROR;