Throw exception if parameter has wrong type in RPC method.

Formally, depending on the method implementation, this kind of error
is just ignored and parameter is skipped. Now aria2 responds error for
these cases. The required parameter checking is also reworked along
with this change.

1 files changed, 32 insertions, 17 deletions

diff --git a/src/RpcMethodImpl.h b/src/RpcMethodImpl.h
index e3fbc338..b17c343a 100644
--- a/src/RpcMethodImpl.h
+++ b/src/RpcMethodImpl.h
@@ -45,6 +45,7 @@
 #include "ValueBase.h"
 #include "TorrentAttribute.h"
 #include "DlAbortEx.h"
+#include "fmt.h"
 
 namespace aria2 {
 
@@ -53,6 +54,28 @@ class RequestGroup;
 
 namespace rpc {
 
+template<typename T>
+const T* checkParam(const RpcRequest& req, size_t index, bool required = false)
+{
+  const T* p = 0;
+  if(req.params->size() > index) {
+    if((p = downcast<T>(req.params->get(index))) == 0) {
+      throw DL_ABORT_EX(fmt("The parameter at %lu has wrong type.",
+                            static_cast<unsigned long>(index)));
+    }
+  } else if(required) {
+    throw DL_ABORT_EX(fmt("The parameter at %lu is required but missing.",
+                          static_cast<unsigned long>(index)));
+  }
+  return p;
+}
+
+template<typename T>
+const T* checkRequiredParam(const RpcRequest& req, size_t index)
+{
+  return checkParam<T>(req, index, true);
+}
+
 template<typename OutputIterator>
 void toStringList(OutputIterator out, const List* src)
 {
@@ -335,27 +358,19 @@ private:
     std::advance(last, lastDistance);
     return std::make_pair(first, last);
   }
-
-  void checkPaginationParams(const SharedHandle<List>& params) const
-  {
-    if(params->size() < 2) {
-      throw DL_ABORT_EX("Invalid argument. Specify offset and num in integer.");
-    }
-    const Integer* p1 = asInteger(params->get(0));
-    const Integer* p2 = asInteger(params->get(1));
-    if(!p1 || !p2 || p2->i() < 0) {
-      throw DL_ABORT_EX("Invalid argument. Specify offset and num in integer.");
-    }
-  }
 protected:
   virtual SharedHandle<ValueBase> process
   (const RpcRequest& req, DownloadEngine* e)
   {
-    const SharedHandle<List>& params = req.params;
-    checkPaginationParams(params);
-    ssize_t offset = req.getIntegerParam(0)->i();
-    size_t num = req.getIntegerParam(1)->i();
-    const List* keysParam = req.getListParam(2);
+    const Integer* offsetParam = checkRequiredParam<Integer>(req, 0);
+    const Integer* numParam = checkRequiredParam<Integer>(req, 1);
+    const List* keysParam = checkParam<List>(req, 2);
+
+    if(numParam->i() < 0) {
+      throw DL_ABORT_EX("The parameter num must be zero or positive integer.");
+    }
+    ssize_t offset = offsetParam->i();
+    size_t num = numParam->i();
     std::vector<std::string> keys;
     toStringList(std::back_inserter(keys), keysParam);
     const std::deque<SharedHandle<T> >& items = getItems(e);