fix comphelper::WeakComponentImplHelper::query

Which was not hanling queries for sub-interfaces.

We need to copy the complicated query function from cppuhelper,
unfortunatly. It has a signature that includes the base class, so we
cant re-use it.

Change-Id: I3668abb67c6cb669086ce32505b383ac11d3c3ab
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/127511
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 181 insertions, 0 deletions

diff --git a/comphelper/source/misc/compbase.cxx b/comphelper/source/misc/compbase.cxx
index 6e2019a255ae..ff3c4778b2ba 100644
--- a/comphelper/source/misc/compbase.cxx
+++ b/comphelper/source/misc/compbase.cxx
@@ -8,6 +8,8 @@
  */
 
 #include <comphelper/compbase.hxx>
+#include <sal/log.hxx>
+#include <osl/diagnose.h>
 
 namespace comphelper
 {
@@ -45,6 +47,185 @@ void SAL_CALL WeakComponentImplHelperBase::removeEventListener(
     maEventListeners.removeInterface(rxListener);
 }
 
+css::uno::Any SAL_CALL WeakComponentImplHelperBase::queryInterface(css::uno::Type const& rType)
+{
+    css::uno::Any aReturn = ::cppu::queryInterface(rType, static_cast<css::uno::XWeak*>(this),
+                                                   static_cast<css::lang::XComponent*>(this));
+    if (aReturn.hasValue())
+        return aReturn;
+    return OWeakObject::queryInterface(rType);
+}
+
+static void checkInterface(css::uno::Type const& rType)
+{
+    if (css::uno::TypeClass_INTERFACE != rType.getTypeClass())
+    {
+        OUString msg("querying for interface \"" + rType.getTypeName() + "\": no interface type!");
+        SAL_WARN("cppuhelper", msg);
+        throw css::uno::RuntimeException(msg);
+    }
+}
+
+static bool isXInterface(rtl_uString* pStr)
+{
+    return OUString::unacquired(&pStr) == "com.sun.star.uno.XInterface";
+}
+
+static bool td_equals(typelib_TypeDescriptionReference const* pTDR1,
+                      typelib_TypeDescriptionReference const* pTDR2)
+{
+    return ((pTDR1 == pTDR2)
+            || OUString::unacquired(&pTDR1->pTypeName) == OUString::unacquired(&pTDR2->pTypeName));
+}
+
+static cppu::type_entry* getTypeEntries(cppu::class_data* cd)
+{
+    cppu::type_entry* pEntries = cd->m_typeEntries;
+    if (!cd->m_storedTypeRefs) // not inited?
+    {
+        static std::mutex aMutex;
+        std::scoped_lock guard(aMutex);
+        if (!cd->m_storedTypeRefs) // not inited?
+        {
+            // get all types
+            for (sal_Int32 n = cd->m_nTypes; n--;)
+            {
+                cppu::type_entry* pEntry = &pEntries[n];
+                css::uno::Type const& rType = (*pEntry->m_type.getCppuType)(nullptr);
+                OSL_ENSURE(rType.getTypeClass() == css::uno::TypeClass_INTERFACE,
+                           "### wrong helper init: expected interface!");
+                OSL_ENSURE(
+                    !isXInterface(rType.getTypeLibType()->pTypeName),
+                    "### want to implement XInterface: template argument is XInterface?!?!?!");
+                if (rType.getTypeClass() != css::uno::TypeClass_INTERFACE)
+                {
+                    OUString msg("type \"" + rType.getTypeName() + "\" is no interface type!");
+                    SAL_WARN("cppuhelper", msg);
+                    throw css::uno::RuntimeException(msg);
+                }
+                // ref is statically held by getCppuType()
+                pEntry->m_type.typeRef = rType.getTypeLibType();
+            }
+            OSL_DOUBLE_CHECKED_LOCKING_MEMORY_BARRIER();
+            cd->m_storedTypeRefs = true;
+        }
+    }
+    else
+    {
+        OSL_DOUBLE_CHECKED_LOCKING_MEMORY_BARRIER();
+    }
+    return pEntries;
+}
+
+static void* makeInterface(sal_IntPtr nOffset, void* that)
+{
+    return (static_cast<char*>(that) + nOffset);
+}
+
+static bool recursivelyFindType(typelib_TypeDescriptionReference const* demandedType,
+                                typelib_InterfaceTypeDescription const* type, sal_IntPtr* offset)
+{
+    // This code assumes that the vtables of a multiple-inheritance class (the
+    // offset amount by which to adjust the this pointer) follow one another in
+    // the object layout, and that they contain slots for the inherited classes
+    // in a specific order.  In theory, that need not hold for any given
+    // platform; in practice, it seems to work well on all supported platforms:
+next:
+    for (sal_Int32 i = 0; i < type->nBaseTypes; ++i)
+    {
+        if (i > 0)
+        {
+            *offset += sizeof(void*);
+        }
+        typelib_InterfaceTypeDescription const* base = type->ppBaseTypes[i];
+        // ignore XInterface:
+        if (base->nBaseTypes > 0)
+        {
+            if (td_equals(reinterpret_cast<typelib_TypeDescriptionReference const*>(base),
+                          demandedType))
+            {
+                return true;
+            }
+            // Profiling showed that it is important to speed up the common case
+            // of only one base:
+            if (type->nBaseTypes == 1)
+            {
+                type = base;
+                goto next;
+            }
+            if (recursivelyFindType(demandedType, base, offset))
+            {
+                return true;
+            }
+        }
+    }
+    return false;
+}
+
+static void* queryDeepNoXInterface(typelib_TypeDescriptionReference const* pDemandedTDR,
+                                   cppu::class_data* cd, void* that)
+{
+    cppu::type_entry* pEntries = getTypeEntries(cd);
+    sal_Int32 nTypes = cd->m_nTypes;
+    sal_Int32 n;
+
+    // try top interfaces without getting td
+    for (n = 0; n < nTypes; ++n)
+    {
+        if (td_equals(pEntries[n].m_type.typeRef, pDemandedTDR))
+        {
+            return makeInterface(pEntries[n].m_offset, that);
+        }
+    }
+    // query deep getting td
+    for (n = 0; n < nTypes; ++n)
+    {
+        typelib_TypeDescription* pTD = nullptr;
+        TYPELIB_DANGER_GET(&pTD, pEntries[n].m_type.typeRef);
+        if (pTD)
+        {
+            // exclude top (already tested) and bottom (XInterface) interface
+            OSL_ENSURE(reinterpret_cast<typelib_InterfaceTypeDescription*>(pTD)->nBaseTypes > 0,
+                       "### want to implement XInterface:"
+                       " template argument is XInterface?!?!?!");
+            sal_IntPtr offset = pEntries[n].m_offset;
+            bool found = recursivelyFindType(
+                pDemandedTDR, reinterpret_cast<typelib_InterfaceTypeDescription*>(pTD), &offset);
+            TYPELIB_DANGER_RELEASE(pTD);
+            if (found)
+            {
+                return makeInterface(offset, that);
+            }
+        }
+        else
+        {
+            OUString msg("cannot get type description for type \""
+                         + OUString::unacquired(&pEntries[n].m_type.typeRef->pTypeName) + "\"!");
+            SAL_WARN("cppuhelper", msg);
+            throw css::uno::RuntimeException(msg);
+        }
+    }
+    return nullptr;
+}
+
+css::uno::Any WeakComponentImplHelper_query(css::uno::Type const& rType, cppu::class_data* cd,
+                                            WeakComponentImplHelperBase* pBase)
+{
+    checkInterface(rType);
+    typelib_TypeDescriptionReference* pTDR = rType.getTypeLibType();
+
+    // shortcut XInterface to WeakComponentImplHelperBase
+    if (!isXInterface(pTDR->pTypeName))
+    {
+        void* p = queryDeepNoXInterface(pTDR, cd, pBase);
+        if (p)
+        {
+            return css::uno::Any(&p, pTDR);
+        }
+    }
+    return pBase->comphelper::WeakComponentImplHelperBase::queryInterface(rType);
+}
+
 } // namespace comphelper
 
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