Syntax
Parameters
context  _In_opt_ void*
The context member of the PFLocalStorageHooks structure that you passed to PFPlatformLocalStorageSetHandlers. Can be nullptr. PlayFab doesn’t own this pointer.
key  _In_z_ const char*
Identifies the data. Typically a file path. Read the data stored under this key.
async  _Inout_ XAsyncBlock*
The XAsyncBlock for the read operation.
Return value
Type: HRESULT ReturnS_OK if you started the asynchronous operation on async, for example with XAsyncBegin. If the handler returns a failure HRESULT, PlayFab fails the storage operation with that HRESULT and doesn’t wait for async to complete, so return a failure only when you haven’t started an operation on async. Report the result of the storage operation itself by completing async with XAsyncComplete.
Remarks
To install this handler, set it in theread member of a PFLocalStorageHooks structure, together with the other two storage handlers, and pass the structure to PFPlatformLocalStorageSetHandlers before you call PFInitialize. PFPlatformLocalStorageSetHandlers returns E_INVALIDARG if any of the three handlers is nullptr. If you don’t set custom handlers, PlayFab uses a default implementation based on cstdio and std::fstream objects.
Complete async with XAsyncComplete, passing the result of the read and the size, in bytes, of the data that you read. PlayFab then calls XAsyncGetResultSize and XAsyncGetResult to copy the data, so your provider must copy the data into the buffer member of XAsyncProviderData when it receives XAsyncOp::GetResult.
If no data is stored under key, the default implementation completes the operation with S_OK and a result size of 0. Do the same in your handler.
PlayFab can call this handler inline on the thread that starts the storage operation, so don’t depend on which thread it runs on. The queue of async is a queue that PlayFab derives from the queueHandle member of PFLocalStorageHooks. If queueHandle is nullptr, PlayFab derives it from the background queue that you passed to PFInitialize, or from the process task queue if that queue was also nullptr. The work and completion callbacks of the derived queue both run on the work port of the queue that it’s derived from.
PlayFab runs one storage operation at a time and starts the next one only after the current one completes.
PlayFab can cancel a pending operation by calling XAsyncCancel on async. Handle XAsyncOp::Cancel in your provider if your storage operation can be canceled.
The key and async arguments are owned by PlayFab and stay valid until the operation completes. The context argument isn’t covered by this guarantee.