Add an error formatter for StatusIB encapsulated in CHIP_ERROR.

src/app/InteractionModelEngine.cpp

@@ -48,6 +48,8 @@ CHIP_ERROR InteractionModelEngine::Init(Messaging::ExchangeManager * apExchangeM
 
     mMagic++;
 
+    StatusIB::RegisterErrorFormatter();
+
     return CHIP_NO_ERROR;
 }
 

src/app/MessageDef/StatusIB.cpp

@@ -30,6 +30,8 @@
 #include <stdio.h>
 
 #include <app/AppBuildConfig.h>
+#include <lib/core/CHIPCore.h>
+#include <lib/support/ErrorStr.h>
 
 using namespace chip;
 using namespace chip::TLV;
@@ -183,5 +185,49 @@ void StatusIB::InitFromChipError(CHIP_ERROR aError)
     mStatus = Status::Failure;
 }
 
+namespace {
+bool FormatStatusIBError(char * buf, uint16_t bufSize, CHIP_ERROR err)
+{
+    if (!err.IsIMStatus())
+    {
+        return false;
+    }
+
+    const char * desc = nullptr;
+#if !CHIP_CONFIG_SHORT_ERROR_STR
+    constexpr char generalFormat[] = "General error: 0x%02" PRIx8;
+    constexpr char clusterFormat[] = "Cluster-specific error: 0x%02" PRIx8;
+
+    // Formatting an 8-bit int will take at most 2 chars, and replace the '%'
+    // and the format letter(s) for PRIx8, so a buffer big enough to hold our
+    // format string will also hold our formatted string.
+    constexpr size_t formattedSize = max(sizeof(generalFormat), sizeof(clusterFormat));
+    char formattedString[formattedSize];
+
+    StatusIB status;
+    status.InitFromChipError(err);
+    if (status.mClusterStatus.HasValue())
+    {
+        snprintf(formattedString, formattedSize, clusterFormat, status.mClusterStatus.Value());
+    }
+    else
+    {
+        snprintf(formattedString, formattedSize, generalFormat, to_underlying(status.mStatus));
+    }
+    desc = formattedString;
+#endif // !CHIP_CONFIG_SHORT_ERROR_STR
+    FormatError(buf, bufSize, "IM", err, desc);
+
+    return true;
+}
+} // anonymous namespace
+
+void StatusIB::RegisterErrorFormatter()
+{
+    static ErrorFormatter sStatusIBErrorFormatter = { FormatStatusIBError, nullptr };
+
+    ::RegisterErrorFormatter(&sStatusIBErrorFormatter);
+}
+
 }; // namespace app
 }; // namespace chip

src/app/MessageDef/StatusIB.h

@@ -110,6 +110,11 @@ struct StatusIB
      */
     void InitFromChipError(CHIP_ERROR aError);
 
+    /**
+     * Register the StatusIB error formatter.
+     */
+    static void RegisterErrorFormatter();
+
     Protocols::InteractionModel::Status mStatus = Protocols::InteractionModel::Status::Success;
     Optional<ClusterStatus> mClusterStatus      = Optional<ClusterStatus>::Missing();
 

src/app/tests/TestStatusIB.cpp

@@ -19,6 +19,7 @@
 #include <app/MessageDef/StatusIB.h>
 #include <lib/core/CHIPError.h>
 #include <lib/support/CHIPMem.h>
+#include <lib/support/ErrorStr.h>
 #include <lib/support/UnitTestRegistration.h>
 
 #include <nlunit-test.h>
@@ -88,10 +89,30 @@ void TestStatusIBToFromChipError(nlTestSuite * aSuite, void * aContext)
     }
 }
 
+#if !CHIP_CONFIG_SHORT_ERROR_STR
+void TestStatusIBErrorToString(nlTestSuite * aSuite, void * aContext)
+{
+    StatusIB status;
+    status.mStatus   = Status::InvalidAction;
+    CHIP_ERROR err   = status.ToChipError();
+    const char * str = ErrorStr(err);
+    NL_TEST_ASSERT(aSuite, strcmp(str, "IM Error 0x00000580: General error: 0x80") == 0);
+
+    status.mStatus        = Status::Failure;
+    status.mClusterStatus = MakeOptional(static_cast<ClusterStatus>(5));
+    err                   = status.ToChipError();
+    str                   = ErrorStr(err);
+    NL_TEST_ASSERT(aSuite, strcmp(str, "IM Error 0x00000605: Cluster-specific error: 0x05") == 0);
+}
+#endif // !CHIP_CONFIG_SHORT_ERROR_STR
+
 // clang-format off
 const nlTest sTests[] =
 {
     NL_TEST_DEF("StatusIBToFromChipError", TestStatusIBToFromChipError),
+#if !CHIP_CONFIG_SHORT_ERROR_STR
+    NL_TEST_DEF("StatusIBErrorToString", TestStatusIBErrorToString),
+#endif // !CHIP_CONFIG_SHORT_ERROR_STR
     NL_TEST_SENTINEL()
 };
 // clang-format on
@@ -105,6 +126,9 @@ static int TestSetup(void * inContext)
     CHIP_ERROR error = chip::Platform::MemoryInit();
     if (error != CHIP_NO_ERROR)
         return FAILURE;
+    // Hand-register the error formatter.  Normally it's registered by
+    // InteractionModelEngine::Init, but we don't want to mess with that here.
+    StatusIB::RegisterErrorFormatter();
     return SUCCESS;
 }