msi: Fix building the message string in MSI_ProcessMessage.

dlls/msi/package.c

@@ -1703,8 +1703,7 @@ MSIHANDLE WINAPI MsiGetActiveDatabase(MSIHANDLE hInstall)
     return handle;
 }
 
-INT MSI_ProcessMessage( MSIPACKAGE *package, INSTALLMESSAGE eMessageType,
-                               MSIRECORD *record)
+INT MSI_ProcessMessage( MSIPACKAGE *package, INSTALLMESSAGE eMessageType, MSIRECORD *record )
 {
     static const WCHAR szActionData[] =
         {'A','c','t','i','o','n','D','a','t','a',0};
@@ -1713,10 +1712,9 @@ INT MSI_ProcessMessage( MSIPACKAGE *package, INSTALLMESSAGE eMessageType,
     static const WCHAR szActionText[] =
         {'A','c','t','i','o','n','T','e','x','t',0};
     LPWSTR message;
-    DWORD sz, total_size = 0, log_type = 0;
-    INT i, rc = 0;
+    DWORD i, len, total_len, log_type = 0;
+    INT rc = 0;
     char *msg;
-    int len;
 
     TRACE("%x\n", eMessageType);
 
@@ -1769,35 +1767,39 @@ INT MSI_ProcessMessage( MSIPACKAGE *package, INSTALLMESSAGE eMessageType,
     }
     else
     {
-        INT msg_field=1;
-        message = msi_alloc(1*sizeof (WCHAR));
-        message[0]=0;
-        msg_field = MSI_RecordGetFieldCount(record);
-        for (i = 1; i <= msg_field; i++)
+        static const WCHAR format[] = {'%','u',':',' ',0};
+        UINT count = MSI_RecordGetFieldCount( record );
+        WCHAR *p;
+
+        total_len = 1;
+        for (i = 1; i <= count; i++)
+        {
+            len = 0;
+            MSI_RecordGetStringW( record, i, NULL, &len );
+            total_len += len + 13;
+        }
+        p = message = msi_alloc( total_len * sizeof(WCHAR) );
+        if (!p) return ERROR_OUTOFMEMORY;
+
+        for (i = 1; i <= count; i++)
         {
-            LPWSTR tmp;
-            WCHAR number[3];
-            static const WCHAR format[] = { '%','i',':',' ',0};
-            sz = 0;
-            MSI_RecordGetStringW(record,i,NULL,&sz);
-            sz+=4;
-            total_size+=sz*sizeof(WCHAR);
-            tmp = msi_alloc(sz*sizeof(WCHAR));
-            message = msi_realloc(message,total_size*sizeof (WCHAR));
-
-            MSI_RecordGetStringW(record,i,tmp,&sz);
-
-            if (msg_field > 1)
+            if (count > 1)
             {
-                sprintfW(number,format,i);
-                strcatW(message,number);
+                len = sprintfW( p, format, i );
+                total_len -= len;
+                p += len;
+            }
+            len = total_len;
+            MSI_RecordGetStringW( record, i, p, &len );
+            total_len -= len;
+            p += len;
+            if (count > 1 && total_len)
+            {
+                *p++ = ' ';
+                total_len--;
             }
-            strcatW(message,tmp);
-            if (msg_field > 1)
-                strcatW(message, szSpace);
-
-            msi_free(tmp);
         }
+        p[0] = 0;
     }
 
     TRACE("%p %p %p %x %x %s\n", gUIHandlerA, gUIHandlerW, gUIHandlerRecord,