Merge pull request #11393 from ghalliday/issue20053

HPCC-20053 Ensure the return type for lookupBlob is consistent

Reviewed-By: Gavin Halliday <gavin.halliday@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>

common/remote/sockfile.cpp

@@ -4021,7 +4021,7 @@ public:
     {
         throwUnexpected();
     }
-    virtual byte * lookupBlob(unsigned __int64 id) override
+    virtual const byte * lookupBlob(unsigned __int64 id) override
     {
         throwUnexpected();
     }
@@ -4218,7 +4218,7 @@ public:
     {
         return makeLocalFposOffset(partNum, prefetchBuffer.tell());
     }
-    virtual byte * lookupBlob(unsigned __int64 id) override
+    virtual const byte * lookupBlob(unsigned __int64 id) override
     {
         throwUnexpected();
     }

ecl/hthor/hthorkey.cpp

@@ -102,7 +102,7 @@ public:
     IMPLEMENT_IINTERFACE_O
 
 //IThorIndexCallback
-    virtual byte * lookupBlob(unsigned __int64 id) override
+    virtual const byte * lookupBlob(unsigned __int64 id) override
     { 
         size32_t dummy; 
         return (byte *) keyManager->loadBlob(id, dummy); 

roxie/ccd/ccdserver.hpp

@@ -284,7 +284,7 @@ public:
     IMPLEMENT_IINTERFACE_O
 
 //IThorIndexCallback
-    virtual byte * lookupBlob(unsigned __int64 id) override
+    virtual const byte * lookupBlob(unsigned __int64 id) override
     { 
         size32_t dummy; 
         cleanupRequired = true;

rtl/eclrtl/rtlkey.hpp

@@ -103,7 +103,7 @@ public:
 
 interface IBlobProvider
 {
-    virtual byte * lookupBlob(unsigned __int64 id) = 0;         // return reference, not freed by code generator, can dispose once transform() has returned.
+    virtual const byte * lookupBlob(unsigned __int64 id) = 0;         // return reference, not freed by code generator, can dispose once transform() has returned.
 };
 
 interface IBlobCreator

rtl/include/eclhelper.hpp

@@ -2308,7 +2308,7 @@ interface IThorDiskCallback : extends IFilePositionProvider
 
 interface IThorIndexCallback : extends IInterface
 {
-    virtual byte * lookupBlob(unsigned __int64 id) = 0;         // return reference, not freed by code generator, can dispose once transform() has returned.
+    virtual const byte * lookupBlob(unsigned __int64 id) = 0;         // return reference, not freed by code generator, can dispose once transform() has returned.
 };
 
 enum

system/jhtree/jhtree.hpp

@@ -302,7 +302,7 @@ public:
         if (klManager)
             klManager->releaseBlobs(); 
     }
-    virtual byte * lookupBlob(unsigned __int64 id) { size32_t dummy; return (byte *) klManager->loadBlob(id, dummy); }
+    virtual const byte * lookupBlob(unsigned __int64 id) { size32_t dummy; return klManager->loadBlob(id, dummy); }
 };
 
 extern jhtree_decl bool isCompressedIndex(const char *filename);

thorlcr/activities/indexread/thindexreadslave.cpp

@@ -81,7 +81,7 @@ protected:
         IMPLEMENT_IINTERFACE_O_USING(CSimpleInterface)
 
     //IThorIndexCallback
-        virtual byte *lookupBlob(unsigned __int64 id) override
+        virtual const byte *lookupBlob(unsigned __int64 id) override
         { 
             size32_t dummy;
             if (!keyManager)