Corrected memory leak from extra memory allocation.

We were allocating twice the memory needed to buffer the QR code string. The second allocation (strdup) was overwriting the assignment of the pointer to the first. Consequently, the first allocation was never free'd. In the end, we don't need to allocate anything ourself and can defer to Apple's Foundation to do that for us.

Author: lcniles

src/device-manager/cocoa/NLWeaveDeviceDescriptor.mm

@@ -34,27 +34,13 @@ + (instancetype)decodeDeviceDescriptor:(NSString *)descriptorStr
     WDM_LOG_METHOD_SIG();
 
     WEAVE_ERROR err;
-    uint8_t * encodedBuf = NULL;
-    uint32_t encodedLen;
     WeaveDeviceDescriptor deviceDesc;
-
-    NLWeaveDeviceDescriptor * nlDeviceDescriptor = nil;
-
-    encodedLen = [descriptorStr length];
-
-    encodedBuf = (uint8_t *) malloc(encodedLen + 1);
-    encodedBuf = (uint8_t *) strdup([descriptorStr UTF8String]);
-
-    err = WeaveDeviceDescriptor::Decode(encodedBuf, encodedLen, deviceDesc);
+    NSData *buffer = [descriptorStr dataUsingEncoding:NSUTF8StringEncoding];
+    err = WeaveDeviceDescriptor::Decode((const uint8_t *)buffer.bytes, (uint32_t)buffer.length, deviceDesc);
     SuccessOrExit(err);
 
-    nlDeviceDescriptor = [NLWeaveDeviceDescriptor createUsing:deviceDesc];
-
 exit:
-    if (encodedBuf != NULL)
-        free((uint8_t *) encodedBuf);
-
-    return nlDeviceDescriptor;
+    return [NLWeaveDeviceDescriptor createUsing:deviceDesc];
 }
 
 + (NLWeaveDeviceDescriptor *)createUsing:(WeaveDeviceDescriptor)deviceDescriptor