AZ::IO::StreamStackEntry Class Reference

#include <StreamStackEntry.h>

Inherited by AZ::IO::BlockCache, AZ::IO::DedicatedCache, AZ::IO::FullFileDecompressor, AZ::IO::ReadSplitter, AZ::IO::StorageDrive, and AZ::IO::StorageDriveWin.

Classes
struct	Status

Public Member Functions
	StreamStackEntry (AZStd::string &&name)
virtual const AZStd::string &	GetName () const
	Returns the name that uniquely identifies this entry.
virtual void	SetNext (AZStd::shared_ptr< StreamStackEntry > next)
virtual AZStd::shared_ptr< StreamStackEntry >	GetNext () const
virtual void	SetContext (StreamerContext &context)
virtual void	PrepareRequest (FileRequest *request)
virtual void	QueueRequest (FileRequest *request)
virtual bool	ExecuteRequests ()
virtual void	UpdateStatus (Status &status) const
	Gets a combined status update from all the nodes in the stack.
virtual void	UpdateCompletionEstimates (AZStd::chrono::steady_clock::time_point now, AZStd::vector< FileRequest * > &internalPending, StreamerContext::PreparedQueue::iterator pendingBegin, StreamerContext::PreparedQueue::iterator pendingEnd)
virtual void	CollectStatistics (AZStd::vector< Statistic > &statistics) const

Protected Attributes
AZStd::string	m_name
	The name that uniquely identifies this entry.
AZStd::shared_ptr< StreamStackEntry >	m_next
	The next entry in the stack.
StreamerContext *	m_context
	Context information for the entire streaming stack.

Detailed Description

The StreamStack is a stack of elements that serve a specific file IO function such collecting information from a file, cache read data, decompressing data, etc. The basic functionality tries perform its task and if it fails pass the request to the next entry in the stack. For instance if a request isn't cached it passes the request to the next entry which might read it from disk instead.

Member Function Documentation

CollectStatistics()

virtual void AZ::IO::StreamStackEntry::CollectStatistics ( AZStd::vector< Statistic > &  statistics ) const

virtual

Collect various statistics on this stack entry. These are for profiling and debugging purposes only.

Reimplemented in AZ::IO::BlockCache, AZ::IO::DedicatedCache, AZ::IO::FullFileDecompressor, AZ::IO::ReadSplitter, AZ::IO::StorageDrive, and AZ::IO::StorageDriveWin.

ExecuteRequests()

virtual bool AZ::IO::StreamStackEntry::ExecuteRequests ( )

virtual

Executes one or more queued requests. This is needed for synchronously executing requests, but asynchronous requests can already be running from the PrepareRequest call in which case this call is ignored.

Returns

True if a request was processed, otherwise false.

Reimplemented in AZ::IO::BlockCache, AZ::IO::DedicatedCache, AZ::IO::FullFileDecompressor, AZ::IO::StorageDrive, and AZ::IO::StorageDriveWin.

GetNext()

virtual AZStd::shared_ptr< StreamStackEntry > AZ::IO::StreamStackEntry::GetNext ( ) const

virtual

Returns the next entry in the stack that handles a request if this request can't handle the request, or null if there are no more entries.

PrepareRequest()

virtual void AZ::IO::StreamStackEntry::PrepareRequest ( FileRequest *  request )

virtual

Prepare an external request for processing. This can include resolving file paths, create more specific internal requests, etc. The returned will be queued for further processing by QueueRequest and ExecuteRequest.

Reimplemented in AZ::IO::DedicatedCache, AZ::IO::FullFileDecompressor, AZ::IO::StorageDrive, and AZ::IO::StorageDriveWin.

QueueRequest()

virtual void AZ::IO::StreamStackEntry::QueueRequest ( FileRequest *  request )

virtual

Queues a request to be executed at a later point when ExecuteRequests is called. This can include splitting up the request in more fine-grained steps.

Reimplemented in AZ::IO::BlockCache, AZ::IO::DedicatedCache, AZ::IO::FullFileDecompressor, AZ::IO::ReadSplitter, AZ::IO::StorageDrive, and AZ::IO::StorageDriveWin.

SetNext()

virtual void AZ::IO::StreamStackEntry::SetNext ( AZStd::shared_ptr< StreamStackEntry >  next )

virtual

Set the next entry in the stack or reset it by using a nullptr. If the next entry has already been set, this will overwrite it.

Reimplemented in AZ::IO::DedicatedCache, and AZ::IO::StorageDrive.

UpdateCompletionEstimates()

virtual void AZ::IO::StreamStackEntry::UpdateCompletionEstimates ( AZStd::chrono::steady_clock::time_point  now, AZStd::vector< FileRequest * > &  internalPending, StreamerContext::PreparedQueue::iterator  pendingBegin, StreamerContext::PreparedQueue::iterator  pendingEnd  )

virtual

Updates the estimate of the time the requests will complete. This generally works by bubbling up the estimation and each stack entry adding it's additional overhead if any. When chaining this call, first call the next entry in the stack before adding the current entry's estimate.

Parameters

now	The current time. This is captured once to avoid repeatedly querying the system clock.
internalPending	The requests that are pending in the stream stack. These are always estimated as coming after the queued requests. Because this call will go from the top of the stack to the bottom, but estimation is calculated from the bottom to the top, this list should be processed in reverse order.
pendingBegin	Iterator pointing to the start of the requests that are waiting for a processing slot in the stack.
pendingEnd	Iterator pointing to the end of the requests that are waiting for a processing slot in the stack.

Reimplemented in AZ::IO::BlockCache, AZ::IO::DedicatedCache, AZ::IO::FullFileDecompressor, AZ::IO::StorageDrive, and AZ::IO::StorageDriveWin.

UpdateStatus()

virtual void AZ::IO::StreamStackEntry::UpdateStatus ( Status &  status ) const

virtual

Gets a combined status update from all the nodes in the stack.

Reimplemented in AZ::IO::BlockCache, AZ::IO::DedicatedCache, AZ::IO::FullFileDecompressor, AZ::IO::ReadSplitter, AZ::IO::StorageDrive, and AZ::IO::StorageDriveWin.

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The documentation for this class was generated from the following file:

• Code/Framework/AzCore/AzCore/IO/Streamer/StreamStackEntry.h