commit e1c599b52fcce94bd27ebbc4d74cd59c9e71b452
author Dan Stoza <stoza@google.com> Thu Mar 30 16:37:19 2017 -0700
committer Dan Stoza <stoza@google.com> Thu Apr 06 11:42:38 2017 -0700
tree df4b3a3a154ecc3950d03ed37e912526fa6c6f6c
parent a5f61dd70ac151c8adbde20d3bc4cd7d27808d21

libgui: Normalize IDisplayEventConnection methods

This change modifies the IDisplayEventConnection API such that every
synchronous method returns a status_t (to be able to return transport
errors). This required changing getDataChannel to return its channel by
output parameter rather than return type.

Currently no more error messages are checked than before, but this will
both enable calling code to check error messages if it desires and,
more importantly, allow the Bp/Bn code to be semi-automatically
generated using SafeInterface.

Test: libgui_tests + manual testing
Change-Id: I8d5bc5ef0475cee07b638a97079b234f0384c022

libs/gui/DisplayEventReceiver.cpp

diff --git a/libs/gui/DisplayEventReceiver.cpp b/libs/gui/DisplayEventReceiver.cpp
index 07e07e0..16b06e9 100644
--- a/libs/gui/DisplayEventReceiver.cpp
+++ b/libs/gui/DisplayEventReceiver.cpp
@@ -37,7 +37,7 @@
     if (sf != NULL) {
         mEventConnection = sf->createDisplayEventConnection();
         if (mEventConnection != NULL) {
-            mDataChannel = mEventConnection->getDataChannel();
+            mEventConnection->getDataChannel(&mDataChannel);
         }
     }
 }

libs/gui/IDisplayEventConnection.cpp

diff --git a/libs/gui/IDisplayEventConnection.cpp b/libs/gui/IDisplayEventConnection.cpp
index 4d2d7e9..2de2f8a 100644
--- a/libs/gui/IDisplayEventConnection.cpp
+++ b/libs/gui/IDisplayEventConnection.cpp
@@ -29,23 +29,25 @@
     explicit BpDisplayEventConnection(const sp<IBinder>& impl)
           : BpInterface<IDisplayEventConnection>(impl) {}
 
-    virtual ~BpDisplayEventConnection();
+    ~BpDisplayEventConnection() override;
 
-    virtual sp<BitTube> getDataChannel() const {
+    status_t getDataChannel(sp<BitTube>* outChannel) const override {
         Parcel data, reply;
         data.writeInterfaceToken(IDisplayEventConnection::getInterfaceDescriptor());
         remote()->transact(GET_DATA_CHANNEL, data, &reply);
-        return new BitTube(reply);
+        *outChannel = new BitTube(reply);
+        return NO_ERROR;
     }
 
-    virtual void setVsyncRate(uint32_t count) {
+    status_t setVsyncRate(uint32_t count) override {
         Parcel data, reply;
         data.writeInterfaceToken(IDisplayEventConnection::getInterfaceDescriptor());
         data.writeUint32(count);
         remote()->transact(SET_VSYNC_RATE, data, &reply);
+        return NO_ERROR;
     }
 
-    virtual void requestNextVsync() {
+    void requestNextVsync() override {
         Parcel data, reply;
         data.writeInterfaceToken(IDisplayEventConnection::getInterfaceDescriptor());
         remote()->transact(REQUEST_NEXT_VSYNC, data, &reply, IBinder::FLAG_ONEWAY);
@@ -63,7 +65,8 @@
     switch (code) {
         case GET_DATA_CHANNEL: {
             CHECK_INTERFACE(IDisplayEventConnection, data, reply);
-            sp<BitTube> channel(getDataChannel());
+            sp<BitTube> channel;
+            getDataChannel(&channel);
             channel->writeToParcel(reply);
             return NO_ERROR;
         }