improve [un]marshalling of non-binder objects

this change introduces a new class LightFlattenable<> which is
a protocol to flatten simple objects that don't require
binders or file descriptors; the benefit of this protocol is that
it doesn't require the objects to have a virtual table and give us
a consitant way of doing this.

we also introduce an implementation of this protocol for
POD structures, LightFlattenablePod<>.

Parcel has been update to handle this protocol automatically.

Sensor, Rect, Point and Region now use this new protocol.

Change-Id: Icb3ce7fa1d785249eb666f39c2129f2fc143ea4a

3 files changed, 11 insertions, 33 deletions

diff --git a/libs/gui/ISensorServer.cpp b/libs/gui/ISensorServer.cpp
index 7111092..0b76f37 100644
--- a/libs/gui/ISensorServer.cpp
+++ b/libs/gui/ISensorServer.cpp
@@ -55,7 +55,7 @@ public:
         int32_t n = reply.readInt32();
         v.setCapacity(n);
         while (n--) {
-            reply.read(static_cast<Flattenable&>(s));
+            reply.read(s);
             v.add(s);
         }
         return v;
@@ -84,7 +84,7 @@ status_t BnSensorServer::onTransact(
             size_t n = v.size();
             reply->writeInt32(n);
             for (size_t i=0 ; i<n ; i++) {
-                reply->write(static_cast<const Flattenable&>(v[i]));
+                reply->write(v[i]);
             }
             return NO_ERROR;
         } break;
diff --git a/libs/gui/LayerState.cpp b/libs/gui/LayerState.cpp
index 07f62c4..e2604f8 100644
--- a/libs/gui/LayerState.cpp
+++ b/libs/gui/LayerState.cpp
@@ -26,14 +26,7 @@ status_t layer_state_t::write(Parcel& output) const
 {
     status_t err;
 
-    size_t len = transparentRegion.write(NULL, 0);
-    err = output.writeInt32(len);
-    if (err < NO_ERROR) return err;
-
-    void* buf = output.writeInplace(len);
-    if (buf == NULL) return NO_MEMORY;
-
-    err = transparentRegion.write(buf, len);
+    err = output.write(transparentRegion);
     if (err < NO_ERROR) return err;
 
     // NOTE: regions are at the end of the structure
@@ -46,11 +39,8 @@ status_t layer_state_t::write(Parcel& output) const
 status_t layer_state_t::read(const Parcel& input)
 {
     status_t err;
-    size_t len = input.readInt32();
-    void const* buf = input.readInplace(len);
-    if (buf == NULL) return NO_MEMORY;
 
-    err = transparentRegion.read(buf);
+    err = input.read(transparentRegion);
     if (err < NO_ERROR) return err;
 
     // NOTE: regions are at the end of the structure
@@ -77,8 +67,8 @@ status_t DisplayState::write(Parcel& output) const {
     output.writeInt32(what);
     output.writeInt32(layerStack);
     output.writeInt32(orientation);
-    memcpy(output.writeInplace(sizeof(Rect)), &viewport, sizeof(Rect));
-    memcpy(output.writeInplace(sizeof(Rect)), &frame, sizeof(Rect));
+    output.write(viewport);
+    output.write(frame);
     return NO_ERROR;
 }
 
@@ -88,8 +78,8 @@ status_t DisplayState::read(const Parcel& input) {
     what = input.readInt32();
     layerStack = input.readInt32();
     orientation = input.readInt32();
-    memcpy(&viewport, input.readInplace(sizeof(Rect)), sizeof(Rect));
-    memcpy(&frame,    input.readInplace(sizeof(Rect)), sizeof(Rect));
+    input.read(viewport);
+    input.read(frame);
     return NO_ERROR;
 }
 
diff --git a/libs/gui/Sensor.cpp b/libs/gui/Sensor.cpp
index 5cc76b4..c52a88f 100644
--- a/libs/gui/Sensor.cpp
+++ b/libs/gui/Sensor.cpp
@@ -98,7 +98,7 @@ int32_t Sensor::getVersion() const {
     return mVersion;
 }
 
-size_t Sensor::getFlattenedSize() const
+size_t Sensor::getSize() const
 {
     return  sizeof(int32_t) + ((mName.length() + 3) & ~3) +
             sizeof(int32_t) + ((mVendor.length() + 3) & ~3) +
@@ -107,11 +107,6 @@ size_t Sensor::getFlattenedSize() const
             sizeof(int32_t);
 }
 
-size_t Sensor::getFdCount() const
-{
-    return 0;
-}
-
 static inline
 size_t write(void* buffer, size_t offset, const String8& value) {
     memcpy(static_cast<char*>(buffer) + offset, value.string(), value.length());
@@ -130,12 +125,8 @@ size_t write(void* buffer, size_t offset, int32_t value) {
     return sizeof(int32_t);
 }
 
-status_t Sensor::flatten(void* buffer, size_t size,
-        int fds[], size_t count) const
+status_t Sensor::flatten(void* buffer) const
 {
-    if (size < Sensor::getFlattenedSize())
-        return -ENOMEM;
-
     size_t offset = 0;
     offset += write(buffer, offset, int32_t(mName.length()));
     offset += write(buffer, offset, mName);
@@ -149,7 +140,6 @@ status_t Sensor::flatten(void* buffer, size_t size,
     offset += write(buffer, offset, mResolution);
     offset += write(buffer, offset, mPower);
     offset += write(buffer, offset, mMinDelay);
-
     return NO_ERROR;
 }
 
@@ -171,8 +161,7 @@ size_t read(void const* buffer, size_t offset, int32_t* value) {
     return sizeof(int32_t);
 }
 
-status_t Sensor::unflatten(void const* buffer, size_t size,
-        int fds[], size_t count)
+status_t Sensor::unflatten(void const* buffer, size_t size)
 {
     int32_t len;
     size_t offset = 0;
@@ -188,7 +177,6 @@ status_t Sensor::unflatten(void const* buffer, size_t size,
     offset += read(buffer, offset, &mResolution);
     offset += read(buffer, offset, &mPower);
     offset += read(buffer, offset, &mMinDelay);
-
     return NO_ERROR;
 }