Merge pull request #106 from cortex-lab/obj2json_fix

Bug fix for turning empty objects into struct

Author: Jai Bhagat

cb-tools/obj2struct.m

@@ -23,12 +23,15 @@
     end
     s = obj2struct(m);
   else % Normal object
+    s.ClassContructor = class(obj); % Supply class name for loading object
     names = fieldnames(obj); % Get list of public properties
     for i = 1:length(names)
-      if isobject(obj.(names{i})) % Property contains an object
+      if isempty(obj) % Object and therefore all properties are empty
+        s.(names{i}) = [];
+      elseif isobject(obj.(names{i})) % Property contains an object
         if startsWith(class(obj.(names{i})),'daq.ni.')
           % Do not attempt to save ni daq sessions of channels
-          s.(names{i}) = []; 
+          s.(names{i}) = [];
         else % Recurse
           s.(names{i}) = obj2struct(obj.(names{i}));
         end
@@ -55,7 +58,6 @@
         s.(names{i}) = obj.(names{i});
       end
     end
-    s.ClassContructor = class(obj); % Supply class name for loading object
   end
 elseif iscell(obj)
   % If dealing with cell array, recurse through elements

tests/obj2json_test.m

@@ -0,0 +1,23 @@
+%% Test obj2struct with given data
+data = struct;
+data.A = struct(... % Scalar struct
+  'field1', zeros(10), ...
+  'field2', true(10), ...
+  'field3', pi, ...
+  'field4', single(10), ...
+  'field5', '10');
+data.B = hw.DaqController(); % Obj containing empty obj
+v = daq.getVendors();
+if v(strcmp({v.ID},'ni')).IsOperational
+  data.B.createDaqChannels(); % Add daq.ni obj
+end
+data.C = struct; % Non-scalar struct
+data.C(1,1).a = 1;
+data.C(2,1).a = 2;
+data.C(1,2).a = 3;
+data.C(2,2).a = 4;
+data.D = @(a,b,c)zeros(c,b,a); % Function handle
+
+json = obj2json(data);
+out = '{"A":{"field1":[[0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,0,0]],"field2":[[true,true,true,true,true,true,true,true,true,true],[true,true,true,true,true,true,true,true,true,true],[true,true,true,true,true,true,true,true,true,true],[true,true,true,true,true,true,true,true,true,true],[true,true,true,true,true,true,true,true,true,true],[true,true,true,true,true,true,true,true,true,true],[true,true,true,true,true,true,true,true,true,true],[true,true,true,true,true,true,true,true,true,true],[true,true,true,true,true,true,true,true,true,true],[true,true,true,true,true,true,true,true,true,true]],"field3":3.1415926535897931,"field4":10,"field5":"10"},"B":{"ClassContructor":"hw.DaqController","ChannelNames":[],"SignalGenerators":{"ClassContructor":"hw.PulseSwitcher","OpenValue":[],"ClosedValue":[],"ParamsFun":[],"DefaultCommand":[],"DefaultValue":[]},"DaqIds":"Dev1","DaqChannelIds":[],"SampleRate":1000,"DaqSession":[],"DigitalDaqSession":[],"Value":[],"NumChannels":0,"AnalogueChannelsIdx":[]},"C":[[{"a":1},{"a":3}],[{"a":2},{"a":4}]],"D":"@(a,b,c)zeros(c,b,a)"}';
+assert(strcmp(json,out), 'Test failed')