Add a method for validating data-value dictionaries. (project-chip#36207)

Author: bzbarsky-apple

src/darwin/Framework/CHIP/MTRBaseDevice.mm

@@ -613,7 +613,9 @@ - (void)subscribeWithQueue:(dispatch_queue_t)queue
     }
 }
 
-static CHIP_ERROR MTREncodeTLVFromDataValueDictionaryInternal(id object, chip::TLV::TLVWriter & writer, chip::TLV::Tag tag)
+// writer is allowed to be null to just validate the incoming object without
+// actually encoding.
+static CHIP_ERROR MTREncodeTLVFromDataValueDictionaryInternal(id object, chip::TLV::TLVWriter * writer, chip::TLV::Tag tag)
 {
     if (![object isKindOfClass:[NSDictionary class]]) {
         MTR_LOG_ERROR("Error: Unsupported object to encode: %@", [object class]);
@@ -631,60 +633,62 @@ static CHIP_ERROR MTREncodeTLVFromDataValueDictionaryInternal(id object, chip::T
             MTR_LOG_ERROR("Error: Object to encode has corrupt signed integer type: %@", [value class]);
             return CHIP_ERROR_INVALID_ARGUMENT;
         }
-        return writer.Put(tag, [value longLongValue]);
+        return writer ? writer->Put(tag, [value longLongValue]) : CHIP_NO_ERROR;
     }
     if ([typeName isEqualToString:MTRUnsignedIntegerValueType]) {
         if (![value isKindOfClass:[NSNumber class]]) {
             MTR_LOG_ERROR("Error: Object to encode has corrupt unsigned integer type: %@", [value class]);
             return CHIP_ERROR_INVALID_ARGUMENT;
         }
-        return writer.Put(tag, [value unsignedLongLongValue]);
+        return writer ? writer->Put(tag, [value unsignedLongLongValue]) : CHIP_NO_ERROR;
     }
     if ([typeName isEqualToString:MTRBooleanValueType]) {
         if (![value isKindOfClass:[NSNumber class]]) {
             MTR_LOG_ERROR("Error: Object to encode has corrupt boolean type: %@", [value class]);
             return CHIP_ERROR_INVALID_ARGUMENT;
         }
-        return writer.Put(tag, static_cast<bool>([value boolValue]));
+        return writer ? writer->Put(tag, static_cast<bool>([value boolValue])) : CHIP_NO_ERROR;
     }
     if ([typeName isEqualToString:MTRFloatValueType]) {
         if (![value isKindOfClass:[NSNumber class]]) {
             MTR_LOG_ERROR("Error: Object to encode has corrupt float type: %@", [value class]);
             return CHIP_ERROR_INVALID_ARGUMENT;
         }
-        return writer.Put(tag, [value floatValue]);
+        return writer ? writer->Put(tag, [value floatValue]) : CHIP_NO_ERROR;
     }
     if ([typeName isEqualToString:MTRDoubleValueType]) {
         if (![value isKindOfClass:[NSNumber class]]) {
             MTR_LOG_ERROR("Error: Object to encode has corrupt double type: %@", [value class]);
             return CHIP_ERROR_INVALID_ARGUMENT;
         }
-        return writer.Put(tag, [value doubleValue]);
+        return writer ? writer->Put(tag, [value doubleValue]) : CHIP_NO_ERROR;
     }
     if ([typeName isEqualToString:MTRNullValueType]) {
-        return writer.PutNull(tag);
+        return writer ? writer->PutNull(tag) : CHIP_NO_ERROR;
     }
     if ([typeName isEqualToString:MTRUTF8StringValueType]) {
         if (![value isKindOfClass:[NSString class]]) {
             MTR_LOG_ERROR("Error: Object to encode has corrupt UTF8 string type: %@", [value class]);
             return CHIP_ERROR_INVALID_ARGUMENT;
         }
-        return writer.PutString(tag, AsCharSpan(value));
+        return writer ? writer->PutString(tag, AsCharSpan(value)) : CHIP_NO_ERROR;
     }
     if ([typeName isEqualToString:MTROctetStringValueType]) {
         if (![value isKindOfClass:[NSData class]]) {
             MTR_LOG_ERROR("Error: Object to encode has corrupt octet string type: %@", [value class]);
             return CHIP_ERROR_INVALID_ARGUMENT;
         }
-        return writer.Put(tag, AsByteSpan(value));
+        return writer ? writer->Put(tag, AsByteSpan(value)) : CHIP_NO_ERROR;
     }
     if ([typeName isEqualToString:MTRStructureValueType]) {
         if (![value isKindOfClass:[NSArray class]]) {
             MTR_LOG_ERROR("Error: Object to encode has corrupt structure type: %@", [value class]);
             return CHIP_ERROR_INVALID_ARGUMENT;
         }
-        TLV::TLVType outer;
-        ReturnErrorOnFailure(writer.StartContainer(tag, chip::TLV::kTLVType_Structure, outer));
+        TLV::TLVType outer = TLV::kTLVType_NotSpecified;
+        if (writer) {
+            ReturnErrorOnFailure(writer->StartContainer(tag, chip::TLV::kTLVType_Structure, outer));
+        }
         for (id element in value) {
             if (![element isKindOfClass:[NSDictionary class]]) {
                 MTR_LOG_ERROR("Error: Structure element to encode has corrupt type: %@", [element class]);
@@ -713,16 +717,20 @@ static CHIP_ERROR MTREncodeTLVFromDataValueDictionaryInternal(id object, chip::T
             ReturnErrorOnFailure(
                 MTREncodeTLVFromDataValueDictionaryInternal(elementValue, writer, tag));
         }
-        ReturnErrorOnFailure(writer.EndContainer(outer));
+        if (writer) {
+            ReturnErrorOnFailure(writer->EndContainer(outer));
+        }
         return CHIP_NO_ERROR;
     }
     if ([typeName isEqualToString:MTRArrayValueType]) {
         if (![value isKindOfClass:[NSArray class]]) {
             MTR_LOG_ERROR("Error: Object to encode has corrupt array type: %@", [value class]);
             return CHIP_ERROR_INVALID_ARGUMENT;
         }
-        TLV::TLVType outer;
-        ReturnErrorOnFailure(writer.StartContainer(tag, chip::TLV::kTLVType_Array, outer));
+        TLV::TLVType outer = TLV::kTLVType_NotSpecified;
+        if (writer) {
+            ReturnErrorOnFailure(writer->StartContainer(tag, chip::TLV::kTLVType_Array, outer));
+        }
         for (id element in value) {
             if (![element isKindOfClass:[NSDictionary class]]) {
                 MTR_LOG_ERROR("Error: Array element to encode has corrupt type: %@", [element class]);
@@ -735,14 +743,16 @@ static CHIP_ERROR MTREncodeTLVFromDataValueDictionaryInternal(id object, chip::T
             }
             ReturnErrorOnFailure(MTREncodeTLVFromDataValueDictionaryInternal(elementValue, writer, chip::TLV::AnonymousTag()));
         }
-        ReturnErrorOnFailure(writer.EndContainer(outer));
+        if (writer) {
+            ReturnErrorOnFailure(writer->EndContainer(outer));
+        }
         return CHIP_NO_ERROR;
     }
     MTR_LOG_ERROR("Error: Unsupported type to encode: %@", typeName);
     return CHIP_ERROR_INVALID_ARGUMENT;
 }
 
-static CHIP_ERROR MTREncodeTLVFromDataValueDictionary(id object, chip::TLV::TLVWriter & writer, chip::TLV::Tag tag)
+static CHIP_ERROR MTREncodeTLVFromDataValueDictionary(id object, chip::TLV::TLVWriter * writer, chip::TLV::Tag tag)
 {
     CHIP_ERROR err = MTREncodeTLVFromDataValueDictionaryInternal(object, writer, tag);
     if (err != CHIP_NO_ERROR) {
@@ -761,7 +771,7 @@ static CHIP_ERROR MTREncodeTLVFromDataValueDictionary(id object, chip::TLV::TLVW
     TLV::TLVWriter writer;
     writer.Init(buffer);
 
-    CHIP_ERROR err = MTREncodeTLVFromDataValueDictionary(value, writer, TLV::AnonymousTag());
+    CHIP_ERROR err = MTREncodeTLVFromDataValueDictionary(value, &writer, TLV::AnonymousTag());
     if (err != CHIP_NO_ERROR) {
         if (error) {
             *error = [MTRError errorForCHIPErrorCode:err];
@@ -772,6 +782,11 @@ static CHIP_ERROR MTREncodeTLVFromDataValueDictionary(id object, chip::TLV::TLVW
     return AsData(ByteSpan(buffer, writer.GetLengthWritten()));
 }
 
+BOOL MTRDataValueDictionaryIsWellFormed(MTRDeviceDataValueDictionary value)
+{
+    return MTREncodeTLVFromDataValueDictionary(value, nullptr, TLV::AnonymousTag()) == CHIP_NO_ERROR;
+}
+
 // Callback type to pass data value as an NSObject
 typedef void (*MTRDataValueDictionaryCallback)(void * context, id value);
 
@@ -798,7 +813,7 @@ CHIP_ERROR Decode(chip::TLV::TLVReader & data)
 
     CHIP_ERROR Encode(chip::TLV::TLVWriter & writer, chip::TLV::Tag tag) const
     {
-        return MTREncodeTLVFromDataValueDictionary(decodedObj, writer, tag);
+        return MTREncodeTLVFromDataValueDictionary(decodedObj, &writer, tag);
     }
 
     static constexpr bool kIsFabricScoped = false;
@@ -2212,7 +2227,7 @@ + (NSDictionary *)eventReportForHeader:(const chip::app::EventHeader &)header an
     // Commands never need chained buffers, since they cannot be chunked.
     writer.Init(std::move(buffer), /* useChainedBuffers = */ false);
 
-    CHIP_ERROR errorCode = MTREncodeTLVFromDataValueDictionary(data, writer, TLV::AnonymousTag());
+    CHIP_ERROR errorCode = MTREncodeTLVFromDataValueDictionary(data, &writer, TLV::AnonymousTag());
     if (errorCode != CHIP_NO_ERROR) {
         LogStringAndReturnError(@"Unable to encode data-value to TLV", errorCode, error);
         return System::PacketBufferHandle();
@@ -3082,7 +3097,7 @@ static bool EncodeDataValueToTLV(System::PacketBufferHandle & buffer, Platform::
     System::PacketBufferTLVWriter writer;
     writer.Init(std::move(buffer), /* useChainedBuffers = */ true);
 
-    CHIP_ERROR errorCode = MTREncodeTLVFromDataValueDictionary(data, writer, TLV::AnonymousTag());
+    CHIP_ERROR errorCode = MTREncodeTLVFromDataValueDictionary(data, &writer, TLV::AnonymousTag());
     if (errorCode != CHIP_NO_ERROR) {
         LogStringAndReturnError(@"Unable to encode data-value to TLV", errorCode, error);
         return false;

src/darwin/Framework/CHIP/MTRBaseDevice_Internal.h

@@ -18,6 +18,8 @@
 #import "MTRBaseDevice.h"
 #import <Foundation/Foundation.h>
 
+#import "MTRDeviceDataValueDictionary.h"
+
 #include <app/AttributePathParams.h>
 #include <app/ConcreteAttributePath.h>
 #include <app/ConcreteCommandPath.h>
@@ -257,6 +259,6 @@ NSDictionary<NSString *, id> * _Nullable MTRDecodeDataValueDictionaryFromCHIPTLV
 // TLV Data with an anonymous tag.  This method assumes the encoding of the
 // value fits in a single UDP MTU; for lists this method might need to be used
 // on each list item separately.
-NSData * _Nullable MTREncodeTLVFromDataValueDictionary(NSDictionary<NSString *, id> * value, NSError * __autoreleasing * error);
+NSData * _Nullable MTREncodeTLVFromDataValueDictionary(MTRDeviceDataValueDictionary value, NSError * __autoreleasing * error);
 
 NS_ASSUME_NONNULL_END

src/darwin/Framework/CHIP/MTRDevice_Internal.h

@@ -176,6 +176,13 @@ MTR_DIRECT_MEMBERS
 - (void)devicePrivateInternalStateChanged:(MTRDevice *)device internalState:(NSDictionary *)state;
 @end
 
+// Returns whether a data-value dictionary is well-formed (in the sense that all
+// the types of the objects inside are as expected, so it's actually a valid
+// representation of some TLV).  Implemented in MTRBaseDevice.mm because that's
+// where the pieces needed to implement it are, but declared here so our tests
+// can see it.
+MTR_EXTERN MTR_TESTABLE BOOL MTRDataValueDictionaryIsWellFormed(MTRDeviceDataValueDictionary value);
+
 #pragma mark - Constants
 
 static NSString * const kDefaultSubscriptionPoolSizeOverrideKey = @"subscriptionPoolSizeOverride";