Redmine#7871: use VarRefValueToJson consistently and copy only when n…

…eeded

VarRefValueToJson() was no longer used so
VarRefValueToJsonAllowScalars() was renamed to it.

Fixes a bug in VarRefValueToJsonAllowScalars() that leaked cf_nulls
(typo: used value instead of rp).

Fixes a bug in SeqShuffle() so it doesn't crash with a 0-length
sequence.

For https://dev.cfengine.com/issues/7871 the following functions now
take a list or an array or a data container, or inline JSON: filter(),
getindices(), getvalues(), join(), length(), maplist(), reverse(),
unique(), intersection(), difference(), shuffle(), sort(), storejson(),
string_mustache(), sublist(), sum(), product(); all the rewritten
function got new acceptance tests.

Some tests were redundant and thus removed.

The following functions were left alone because they're either not
needed or too tricky due to legacy issues: regarray(), reglist(),
makerule(), nth()

We only create copies of the variables if needed, and free them only in
that case, which will improve performance.

Changelog: Allow inline JSON to be used in function calls (Redmine#7871).

libutils/json.c

@@ -368,6 +368,14 @@ void JsonDestroy(JsonElement *element)
     }
 }
 
+void JsonDestroyMaybe(JsonElement *element, bool allocated)
+{
+    if (allocated)
+    {
+        JsonDestroy(element);
+    }
+}
+
 JsonElement *JsonArrayMergeArray(const JsonElement *a, const JsonElement *b)
 {
     assert(JsonGetElementType(a) == JsonGetElementType(b));

libutils/json.h

@@ -149,6 +149,13 @@ JsonElement *JsonMerge(const JsonElement *a, const JsonElement *b);
   */
 void JsonDestroy(JsonElement *element);
 
+/**
+  @brief Destroy a JSON element if needed
+  @param element [in] The JSON element to destroy.
+  @param allocated [in] Whether the element was allocated and needs to be destroyed.
+  */
+void JsonDestroyMaybe(JsonElement *element, bool allocated);
+
 /**
   @brief Get the length of a JsonElement. This is the number of elements or fields in an array or object respectively.
   @param element [in] The JSON element.

libutils/sequence.c

@@ -312,11 +312,15 @@ size_t SeqLength(const Seq *seq)
 
 void SeqShuffle(Seq *seq, unsigned int seed)
 {
+    if (0 == SeqLength(seq))
+    {
+        return;
+    }
+
     /* Store current random number state for being reset at the end of function */
     int rand_state = rand();
 
     srand(seed);
-
     for (size_t i = SeqLength(seq) - 1; i > 0; i--)
     {
         size_t j = rand() % (i + 1);