Use AsData and AsString more uniformly in Darwin code.

src/darwin/Framework/CHIP/MTRBaseDevice.mm

@@ -28,6 +28,8 @@
 #import "MTRFramework.h"
 #import "MTRLogging_Internal.h"
 #import "MTRSetupPayload_Internal.h"
+#import "NSDataSpanConversion.h"
+#import "NSStringSpanConversion.h"
 
 #include "app/ConcreteAttributePath.h"
 #include "app/ConcreteCommandPath.h"
@@ -522,26 +524,27 @@ id _Nullable MTRDecodeDataValueDictionaryFromCHIPTLV(chip::TLV::TLVReader * data
             dictionaryWithObjectsAndKeys:MTRDoubleValueType, MTRTypeKey, [NSNumber numberWithDouble:val], MTRValueKey, nil];
     }
     case chip::TLV::kTLVType_UTF8String: {
-        uint32_t len = data->GetLength();
-        const uint8_t * ptr;
-        CHIP_ERROR err = data->GetDataPtr(ptr);
+        CharSpan stringValue;
+        CHIP_ERROR err = data->Get(stringValue);
         if (err != CHIP_NO_ERROR) {
             MTR_LOG_ERROR("Error(%s): TLV UTF8String decoding failed", chip::ErrorStr(err));
             return nil;
         }
-        return [NSDictionary dictionaryWithObjectsAndKeys:MTRUTF8StringValueType, MTRTypeKey,
-                             [[NSString alloc] initWithBytes:ptr length:len encoding:NSUTF8StringEncoding], MTRValueKey, nil];
+        NSString * stringObj = AsString(stringValue);
+        if (stringObj == nil) {
+            MTR_LOG_ERROR("Error(%s): TLV UTF8String value is not actually UTF-8", err.AsString());
+            return nil;
+        }
+        return @ { MTRTypeKey : MTRUTF8StringValueType, MTRValueKey : stringObj };
     }
     case chip::TLV::kTLVType_ByteString: {
-        uint32_t len = data->GetLength();
-        const uint8_t * ptr;
-        CHIP_ERROR err = data->GetDataPtr(ptr);
+        ByteSpan bytesValue;
+        CHIP_ERROR err = data->Get(bytesValue);
         if (err != CHIP_NO_ERROR) {
             MTR_LOG_ERROR("Error(%s): TLV ByteString decoding failed", chip::ErrorStr(err));
             return nil;
         }
-        return [NSDictionary dictionaryWithObjectsAndKeys:MTROctetStringValueType, MTRTypeKey,
-                             [NSData dataWithBytes:ptr length:len], MTRValueKey, nil];
+        return @ { MTRTypeKey : MTROctetStringValueType, MTRValueKey : AsData(bytesValue) };
     }
     case chip::TLV::kTLVType_Null: {
         return [NSDictionary dictionaryWithObjectsAndKeys:MTRNullValueType, MTRTypeKey, nil];
@@ -653,7 +656,7 @@ static CHIP_ERROR MTREncodeTLVFromDataValueDictionary(id object, chip::TLV::TLVW
             MTR_LOG_ERROR("Error: Object to encode has corrupt UTF8 string type: %@", [value class]);
             return CHIP_ERROR_INVALID_ARGUMENT;
         }
-        return writer.PutString(tag, [value cStringUsingEncoding:NSUTF8StringEncoding]);
+        return writer.PutString(tag, [value UTF8String]);
     }
     if ([typeName isEqualToString:MTROctetStringValueType]) {
         if (![value isKindOfClass:[NSData class]]) {

src/darwin/Framework/CHIP/MTRFabricInfo.mm

@@ -65,7 +65,7 @@ - (instancetype)initWithFabricTable:(const FabricTable &)fabricTable fabricInfo:
         return nil;
     }
 
-    _rootPublicKey = [NSData dataWithBytes:publicKey.ConstBytes() length:publicKey.Length()];
+    _rootPublicKey = AsData(ByteSpan(publicKey.ConstBytes(), publicKey.Length()));
 
     _vendorID = @(fabricInfo.GetVendorId());
     _fabricID = @(fabricInfo.GetFabricId());

src/darwin/Framework/CHIP/MTROTAProviderDelegateBridge.mm

@@ -232,8 +232,13 @@ CHIP_ERROR OnTransferSessionBegin(TransferSession::OutputEvent & event)
         uint16_t fdl = 0;
         auto fd = mTransfer.GetFileDesignator(fdl);
         VerifyOrReturnError(fdl <= bdx::kMaxFileDesignatorLen, CHIP_ERROR_INVALID_ARGUMENT);
+        CharSpan fileDesignatorSpan(Uint8::to_const_char(fd), fdl);
+
+        auto fileDesignator = AsString(fileDesignatorSpan);
+        if (fileDesignator == nil) {
+            return CHIP_ERROR_INCORRECT_STATE;
+        }
 
-        auto fileDesignator = [[NSString alloc] initWithBytes:fd length:fdl encoding:NSUTF8StringEncoding];
         auto offset = @(mTransfer.GetStartOffset());
 
         auto * controller = [[MTRDeviceControllerFactory sharedInstance] runningControllerForFabricIndex:mFabricIndex.Value()];
@@ -565,8 +570,8 @@ bool GetPeerNodeInfo(CommandHandler * commandHandler, const ConcreteCommandPath
     if (error != nil) {
         auto * desc = [error description];
         auto err = [MTRError errorToCHIPErrorCode:error];
-        ChipLogError(Controller, "%s: application returned error: '%s', sending error: '%s'", prefix,
-            [desc cStringUsingEncoding:NSUTF8StringEncoding], chip::ErrorStr(err));
+        ChipLogError(
+            Controller, "%s: application returned error: '%s', sending error: '%s'", prefix, desc.UTF8String, err.AsString());
 
         handler->AddStatus(cachedCommandPath, StatusIB(err).mStatus);
         handle.Release();
@@ -635,8 +640,7 @@ bool GetPeerNodeInfo(CommandHandler * commandHandler, const ConcreteCommandPath
                 CommandHandler * handler = EnsureValidState(handle, cachedCommandPath, "QueryImage", data, error);
                 VerifyOrReturn(handler != nullptr);
 
-                ChipLogDetail(Controller, "QueryImage: application responded with: %s",
-                    [[data description] cStringUsingEncoding:NSUTF8StringEncoding]);
+                ChipLogDetail(Controller, "QueryImage: application responded with: %s", [[data description] UTF8String]);
 
                 auto hasUpdate = [data.status isEqual:@(MTROtaSoftwareUpdateProviderOTAQueryStatusUpdateAvailable)];
                 auto isBDXProtocolSupported = [commandParams.protocolsSupported
@@ -753,27 +757,26 @@ bool GetPeerNodeInfo(CommandHandler * commandHandler, const ConcreteCommandPath
     __block CommandHandler::Handle handle(commandObj);
     __block ConcreteCommandPath cachedCommandPath(commandPath.mEndpointId, commandPath.mClusterId, commandPath.mCommandId);
 
-    auto completionHandler
-        = ^(MTROTASoftwareUpdateProviderClusterApplyUpdateResponseParams * _Nullable data, NSError * _Nullable error) {
-              [controller
-                  asyncDispatchToMatterQueue:^() {
-                      assertChipStackLockedByCurrentThread();
-
-                      CommandHandler * handler = EnsureValidState(handle, cachedCommandPath, "ApplyUpdateRequest", data, error);
-                      VerifyOrReturn(handler != nullptr);
-
-                      ChipLogDetail(Controller, "ApplyUpdateRequest: application responded with: %s",
-                          [[data description] cStringUsingEncoding:NSUTF8StringEncoding]);
-
-                      Commands::ApplyUpdateResponse::Type response;
-                      ConvertFromApplyUpdateRequestResponseParms(data, response);
-                      handler->AddResponse(cachedCommandPath, response);
-                      handle.Release();
-                  }
-                                errorHandler:^(NSError *) {
-                                    // Not much we can do here
-                                }];
-          };
+    auto completionHandler = ^(
+        MTROTASoftwareUpdateProviderClusterApplyUpdateResponseParams * _Nullable data, NSError * _Nullable error) {
+        [controller
+            asyncDispatchToMatterQueue:^() {
+                assertChipStackLockedByCurrentThread();
+
+                CommandHandler * handler = EnsureValidState(handle, cachedCommandPath, "ApplyUpdateRequest", data, error);
+                VerifyOrReturn(handler != nullptr);
+
+                ChipLogDetail(Controller, "ApplyUpdateRequest: application responded with: %s", [[data description] UTF8String]);
+
+                Commands::ApplyUpdateResponse::Type response;
+                ConvertFromApplyUpdateRequestResponseParms(data, response);
+                handler->AddResponse(cachedCommandPath, response);
+                handle.Release();
+            }
+                          errorHandler:^(NSError *) {
+                              // Not much we can do here
+                          }];
+    };
 
     auto * commandParams = [[MTROTASoftwareUpdateProviderClusterApplyUpdateRequestParams alloc] init];
     ConvertToApplyUpdateRequestParams(commandData, commandParams);

src/darwin/Framework/CHIP/MTRThreadOperationalDataset.mm

@@ -16,6 +16,7 @@
  */
 
 #import "MTRThreadOperationalDataset.h"
+#import "NSDataSpanConversion.h"
 
 #include "MTRLogging_Internal.h"
 #include <lib/support/Span.h>
@@ -62,7 +63,7 @@ - (instancetype _Nullable)initWithNetworkName:(NSString *)networkName
 - (BOOL)_populateCppOperationalDataset
 {
     _cppThreadOperationalDataset.Clear();
-    _cppThreadOperationalDataset.SetNetworkName([self.networkName cStringUsingEncoding:NSUTF8StringEncoding]);
+    _cppThreadOperationalDataset.SetNetworkName(self.networkName.UTF8String);
 
     if (![self _checkDataLength:self.extendedPANID expectedLength:MTRSizeThreadExtendedPANID]) {
         MTR_LOG_ERROR("Invalid ExtendedPANID");
@@ -137,17 +138,17 @@ - (instancetype _Nullable)initWithData:(NSData *)data
     panID = CFSwapInt16BigToHost(panID);
 
     return [self initWithNetworkName:[NSString stringWithUTF8String:networkName]
-                       extendedPANID:[NSData dataWithBytes:extendedPANID length:MTRSizeThreadExtendedPANID]
-                           masterKey:[NSData dataWithBytes:masterKey length:MTRSizeThreadMasterKey]
-                                PSKc:[NSData dataWithBytes:pskc length:MTRSizeThreadPSKc]
+                       extendedPANID:AsData(chip::ByteSpan(extendedPANID))
+                           masterKey:AsData(chip::ByteSpan(masterKey))
+                                PSKc:AsData(chip::ByteSpan(pskc))
                        channelNumber:@(channel)
                                panID:[NSData dataWithBytes:&panID length:sizeof(uint16_t)]];
 }
 
 - (NSData *)data
 {
     chip::ByteSpan span = _cppThreadOperationalDataset.AsByteSpan();
-    return [NSData dataWithBytes:span.data() length:span.size()];
+    return AsData(span);
 }
 
 @end

src/darwin/Framework/CHIP/templates/MTRAttributeTLVValueDecoder-src.zapt

@@ -3,6 +3,8 @@
 #import "MTRAttributeTLVValueDecoder_Internal.h"
 
 #import "MTRStructsObjc.h"
+#import "NSStringSpanConversion.h"
+#import "NSDataSpanConversion.h"
 
 #include <app/data-model/Decode.h>
 #include <app/data-model/DecodableList.h>

src/darwin/Framework/CHIP/templates/MTRCallbackBridge-src.zapt

@@ -4,6 +4,8 @@
 #import "MTRStructsObjc.h"
 #import "MTRCommandPayloadsObjc.h"
 #import "MTRCommandPayloads_Internal.h"
+#import "NSStringSpanConversion.h"
+#import "NSDataSpanConversion.h"
 
 #include <lib/support/TypeTraits.h>
 

src/darwin/Framework/CHIP/templates/MTRCommandPayloadsObjc-src.zapt

@@ -5,6 +5,8 @@
 #import "MTRBaseDevice_Internal.h"
 #import "MTRError_Internal.h"
 #import "MTRLogging_Internal.h"
+#import "NSStringSpanConversion.h"
+#import "NSDataSpanConversion.h"
 
 #include <lib/core/TLV.h>
 #include <app/data-model/Decode.h>

src/darwin/Framework/CHIP/templates/MTREventTLVValueDecoder-src.zapt

@@ -3,6 +3,8 @@
 #import "MTREventTLVValueDecoder_Internal.h"
 
 #import "MTRStructsObjc.h"
+#import "NSStringSpanConversion.h"
+#import "NSDataSpanConversion.h"
 
 #include <app/data-model/Decode.h>
 #include <app/data-model/DecodableList.h>

src/darwin/Framework/CHIP/templates/partials/decode_value.zapt

@@ -39,9 +39,14 @@
       {{#if_is_strongly_typed_bitmap type}}
           {{target}} = [NSNumber numberWith{{asObjectiveCNumberType "" type false}}:{{source}}.Raw()];
       {{else if (isOctetString type)}}
-        {{target}} = [NSData dataWithBytes:{{source}}.data() length:{{source}}.size()];
+        {{target}} = AsData({{source}});
       {{else if (isCharString type)}}
-        {{target}} = [[NSString alloc] initWithBytes:{{source}}.data() length:{{source}}.size() encoding:NSUTF8StringEncoding];
+        {{target}} = AsString({{source}});
+        if ({{target}} == nil) {
+          {{! Invalid UTF-8.  Just make up an error for now. }}
+          CHIP_ERROR err = CHIP_ERROR_INVALID_ARGUMENT;
+          {{errorCode}}
+        }
       {{else}}
         {{target}} = [NSNumber numberWith{{asObjectiveCNumberType "" type false}}:{{source}}];
       {{/if_is_strongly_typed_bitmap}}