commit a90619662b6d0b1874180d9729719061efe4a570
author Tomasz Wasilczyk <twasilczyk@google.com> Mon Nov 04 12:53:09 2019 -0800
committer Tomasz Wasilczyk <twasilczyk@google.com> Wed Nov 06 14:52:07 2019 -0800
tree 705842cf0bfbc47d5dfcdaaebce2268424d85c06
parent 1cebd62c915b33537e766e6b0baa580b24fa8f31

Improve error handling with separate ICanErrorListener

Error handling highlights:
- moved onError from ICanMessageListener to ICanErrorListener
- added isFatal callback argument to request client disconnect
- don't down interface that's already down

Also:
- don't crash if it's not possible to unregister ICanBus
- don't crash while trying to down interface that failed
- make hidl-utils available to vendor libraries

Bug: 143779011
Test: implemented a VHAL service prototype that communicates with this HAL
Change-Id: I98d054da9da0ead5ef952aebc086e052ac996212

automotive/can/1.0/default/CanBus.h

diff --git a/automotive/can/1.0/default/CanBus.h b/automotive/can/1.0/default/CanBus.h
index 81a83c8..30a2924 100644
--- a/automotive/can/1.0/default/CanBus.h
+++ b/automotive/can/1.0/default/CanBus.h
@@ -34,12 +34,16 @@
 namespace implementation {
 
 struct CanBus : public ICanBus {
+    using ErrorCallback = std::function<void()>;
+
     virtual ~CanBus();
 
     Return<Result> send(const CanMessage& message) override;
     Return<void> listen(const hidl_vec<CanMessageFilter>& filter,
                         const sp<ICanMessageListener>& listener, listen_cb _hidl_cb) override;
+    Return<sp<ICloseHandle>> listenForErrors(const sp<ICanErrorListener>& listener) override;
 
+    void setErrorCallback(ErrorCallback errcb);
     ICanController::Result up();
     bool down();
 
@@ -68,17 +72,22 @@
         sp<ICanMessageListener> callback;
         hidl_vec<CanMessageFilter> filter;
         wp<ICloseHandle> closeHandle;
+        bool failedOnce = false;
     };
-    void clearListeners();
+    void clearMsgListeners();
+    void clearErrListeners();
 
     void onRead(const struct canfd_frame& frame, std::chrono::nanoseconds timestamp);
-    void onError();
+    void onError(int errnoVal);
 
-    std::mutex mListenersGuard;
-    std::vector<CanMessageListener> mListeners GUARDED_BY(mListenersGuard);
+    std::mutex mMsgListenersGuard;
+    std::vector<CanMessageListener> mMsgListeners GUARDED_BY(mMsgListenersGuard);
+
+    std::mutex mErrListenersGuard;
+    std::vector<sp<ICanErrorListener>> mErrListeners GUARDED_BY(mErrListenersGuard);
 
     std::unique_ptr<CanSocket> mSocket;
-    bool mWasUpInitially;
+    bool mDownAfterUse;
 
     /**
      * Guard for up flag is required to be held for entire time when the interface is being used
@@ -87,6 +96,8 @@
      */
     std::mutex mIsUpGuard;
     bool mIsUp GUARDED_BY(mIsUpGuard) = false;
+
+    ErrorCallback mErrCb;
 };
 
 }  // namespace implementation