Reshat Sabiq wrote:
nsCOMPtr<nsICacheSession> cacheSession;
...
nsCOMPtr<nsICacheEntryDescriptor> cacheEntry;
result = cacheSession->OpenCacheEntry(abc, sICache::ACCESS_READ,
PR_TRUE, getter_AddRefs(cacheEntry));
if (NS_FAILED(result))
{
cacheSession = nsnull; // is this necessary? if yes, i should
do it
for cacheEntry as well
It's not necessary, no.
result = cacheService->CreateSession("image",
nsICache::STORE_ANYWHERE,
PR_TRUE, getter_AddRefs
(cacheSession)); // if this assignment, and the one below release the
previous pointers, then = nsnull is unnecessary
|getter_AddRefs(cacheSession)| sets the nsCOMPtr to null as soon as you
try to cast it to an nsICacheSession** (which is what this call does).
So this code pattern is perfectly fine without manually setting to null.
nsISupportsVoid *wrapper;
componentManager->CreateInstanceByContractID
(NS_SUPPORTS_VOID_CONTRACTID, nsnull, NS_GET_IID(nsISupportsVoid),
(void**)&wrapper);
|wrapper| is a COM object like any other. You probably just want to use
nsCOMPtr<nsISupportsVoid> for it....
is the following the right way to reclaim memory?
memoryManager->Free(wrapper);
No, since |wrapper| wasn't allocated by the memory manager... Like I
said, it's just a refcounted object.
I.e., is memoryManager->Free(wrapper); the right way to do it, and will
it also Free the void * contained?
No, destruction of the nsISupportsVoid will not do anything with the
void* (and can't, in fact, since it doesn't know what concrete class it
is and hence whether any destructors need calling); you have to manually
free that memory (using the memoryManager, since that's how it was
allocated) and possiby manually call destructors (if your struct has any).
-Boris
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