Make convertDispparamsArgs() handle mismatch in number of parameters sanely

Parameters come in in reverse order in pdispparams. There might be
less parameters than expected. In that case, assume the missing ones
are "optional" (but can't be marked as such in UNO IDL), and fill in
the rest with empty Anys. There might also be more parameters than
expected. In that case, assume the oovbaapi UNO IDL hasn't kept up
with added optional parameters in MSO, and just ignore the extra ones,
as long as they are empty.

An example: incoming parameters: <12, 13, "foo/bar.tem">

Expected paramters: (string filename, int something, int
somethingElse, Any whatever, Any whateverElse)

Here the existing incoming parameters are placed in reverse order in
the first three outgoing parameters, and the rest of the outgoing
paramters are passed as empty Anys.

Another example: incoming parameters: <EMPTY, TRUE>

Expected parameters: (bool flag)

Here the TRUE is passed as the sole outgoing parameter, and the
incoming EMPTY is ignored.

Still an example: incoming parameters: <"foo.doc", TRUE>

Expected parameters: (bool flag)

This throws an error as the incoming non-empty extra parameter
presumably indicates something important, but there is no
corresponding outgoing parameter to pass it in.

Change-Id: Ib04f9701099ecb899e792d99ff86588022b3bbf6
(cherry picked from commit e4a99a3c502c0285b6fb542d84a9bffde045e526)

1 files changed, 53 insertions, 13 deletions

diff --git a/extensions/source/ole/unoobjw.cxx b/extensions/source/ole/unoobjw.cxx
index 5f8f305c61fb..b4c34f6be881 100644
--- a/extensions/source/ole/unoobjw.cxx
+++ b/extensions/source/ole/unoobjw.cxx
@@ -1253,8 +1253,35 @@ STDMETHODIMP InterfaceOleWrapper::GetIDsOfNames(REFIID /*riid*/,
 void InterfaceOleWrapper::convertDispparamsArgs(DISPID id,
     unsigned short /*wFlags*/, DISPPARAMS* pdispparams, Sequence<Any>& rSeq)
 {
+    // Parameters come in in reverse order in pdispparams. There might be less parameters than
+    // expected. In that case, assume they are "optional" (but can't be marked as such in UNO IDL),
+    // and fill in the rest with empty Anys. There might also be more than expected. In that case,
+    // assume the oovbaapi UNO IDL hasn't kept up with added optional parameters in MSO, and just
+    // ignore the extra ones, as long as they are empty.
+
+    // An example: incoming parameters: <12, 13, "foo/bar.tem">
+    //
+    // Expected paramters: (string filename, int something, int somethingElse, Any whatever, Any
+    // whateverElse)
+    //
+    // Here the existing incoming parameters are placed in reverse order in the first three outgoing
+    // parameters, and the rest of the outgoing paramters are kept as empty Anys.
+    //
+    // Another example: incoming parameters: <EMPTY, TRUE>
+    //
+    // Expected parameters: (bool flag)
+    //
+    // Here the TRUE is passed as the sole outgoing parameter, and the incoming EMPTY is ignored.
+    //
+    // Still an example: incoming parameters: <"foo.doc", TRUE>
+    //
+    // Expected parameters: (bool flag)
+    //
+    // This throws an error as the incoming string parameter presumably should do something important,
+    // but there is no corresponding outgoing parameter.
+
     HRESULT hr = S_OK;
-    const int countArgs = pdispparams->cArgs;
+    const int countIncomingArgs = pdispparams->cArgs;
 
     //Get type information for the current call
     InvocationInfo info;
@@ -1263,33 +1290,39 @@ void InterfaceOleWrapper::convertDispparamsArgs(DISPID id,
                   "[automation bridge]InterfaceOleWrapper::convertDispparamsArgs \n"
                   "Could not obtain type information for current call.");
 
-    // We accept less or even more parameters (on certain conditions) than expected. So size rSeq
-    // according to the number of expected parameters.
-    const int expectedArgs = info.aParamTypes.getLength();
+    // Size rSeq according to the number of expected parameters.
+    const int expectedArgs = info.aParamTypes.getLength() + (info.eMemberType == MemberType_PROPERTY ? 1 : 0);
     rSeq.realloc( expectedArgs );
     Any* pParams = rSeq.getArray();
 
     Any anyParam;
 
-    for (int i = 0; i < std::max(countArgs, expectedArgs); i++)
+    int outgoingArgIndex = 0;
+
+    // Go through incoming parameters in reverse order, i.e. in the order as declared in IDL
+    for (int i = std::max(countIncomingArgs, expectedArgs) - 1; i >= 0; i--)
     {
         // Ignore too many parameters if they are VT_EMPTY anyway
-        if ( i < countArgs && i >= expectedArgs && pdispparams->rgvarg[i].vt == VT_EMPTY )
+        if ( outgoingArgIndex >= expectedArgs && pdispparams->rgvarg[i].vt == VT_EMPTY )
             continue;
 
         // But otherwise too many parameters is an error
-        if ( i < countArgs && i >= expectedArgs )
+        if ( outgoingArgIndex >= expectedArgs )
             throw BridgeRuntimeError( "[automation bridge] Too many parameters" );
 
         if (info.eMemberType == MemberType_METHOD &&
-            info.aParamModes[ expectedArgs - i - 1 ] == ParamMode_OUT)
+            info.aParamModes[ outgoingArgIndex ] == ParamMode_OUT)
+        {
+            outgoingArgIndex++;
             continue;
+        }
 
-        if (i < countArgs)
+        if (i < countIncomingArgs)
         {
             if(convertValueObject( & pdispparams->rgvarg[i], anyParam))
             { //a param is a ValueObject and could be converted
-                pParams[ expectedArgs - i - 1 ] = anyParam;
+                pParams[ outgoingArgIndex ] = anyParam;
+                outgoingArgIndex++;
                 continue;
             }
         }
@@ -1297,6 +1330,7 @@ void InterfaceOleWrapper::convertDispparamsArgs(DISPID id,
         {
             // A missing arg. Let's hope it is de facto optional (there is no way in UNO IDL to mark
             // a parameter as optional). The corresponding slot in pParams is already a void Any.
+            // Here we don't increase outgoingArgIndex!
             continue;
         }
 
@@ -1309,9 +1343,13 @@ void InterfaceOleWrapper::convertDispparamsArgs(DISPID id,
 
         // Check for JScript out and in/out paramsobjects (VT_DISPATCH).
         // To find them out we use typeinformation of the function being called.
+
+        // No idea how this stuff, originally written for JScript, works for other Automation
+        // clients.
+
         if( pdispparams->rgvarg[i].vt == VT_DISPATCH )
         {
-            if( info.eMemberType == MemberType_METHOD && info.aParamModes[ expectedArgs - i - 1 ] == ParamMode_INOUT)
+            if( info.eMemberType == MemberType_METHOD && info.aParamModes[ outgoingArgIndex ] == ParamMode_INOUT)
             {
                 // INOUT-param
                 // Index ( property) "0" contains the actual IN-param. The object is a JScript
@@ -1340,13 +1378,15 @@ void InterfaceOleWrapper::convertDispparamsArgs(DISPID id,
 
         if(info.eMemberType == MemberType_METHOD)
             variantToAny( & varParam, anyParam,
-                           info.aParamTypes[ expectedArgs - i - 1 ]);
+                           info.aParamTypes[ outgoingArgIndex ]);
         else if(info.eMemberType == MemberType_PROPERTY)
             variantToAny( & varParam, anyParam, info.aType);
         else
             OSL_ASSERT(false);
 
-        pParams[ expectedArgs - i - 1 ]= anyParam;
+        if (outgoingArgIndex < expectedArgs)
+            pParams[ outgoingArgIndex ]= anyParam;
+        outgoingArgIndex++;
     }// end for / iterating over all parameters
 }