WorldStatePool Class Reference
#include <WorldStatePool.h>
Inheritance diagram for WorldStatePool:
Detailed Description
holds multiple instances of WorldState, allows one process to be updating while another is readingUse the AutoGetReadState and AutoGetWriteState to access individual WorldState entries... their constructors and destructors allow WorldStatePool to keep track of which entries are in use.
When a state wants to write, it is given the oldest unused entry to write into. During writing, other accessors can read the newest (complete) entry, or concurrently write into a different entry (in case they don't want to wait for the other process to finish).
A global lock (lock) is used while choosing an entry, and individual locks (writeLocks) are used while writing into entries (to easily allow readers to block on the lock until writing is done)
One point of trickiness is that entries being written are moved to the end of the list when the writing begins, not when it is complete. Readers can always scan backwards in the list to find the newest entries, but writers must check the end to see if newer (or equivalent) frames are already in progress, as well as the beginning to find the oldest unreferenced.
When a writer tries to access an entry, and another writer is already processing that frame, if blocking is set then the writer will given that entry once the original is done with it (so check your frame index when you receive it so you can tell if it was already processed). If blocking is *not* set, then you will get a separate entry with no indication another process is also working on the same frame.
Definition at line 42 of file WorldStatePool.h.
Public Member Functions | |
| WorldStatePool () | |
| constructor | |
| WorldStatePool::UpdateInfo * | isUnread (OSensorFrameVectorData &msg, unsigned int &lastFrameNumber) |
| returns true if the process should call WorldState::read (i.e. msg has new or unprocessed data (such as motion needs to supply feedback)) | |
| virtual void | useResource (Data &d) |
| processes a request, passed as either a ReadRequest or WriteRequest, to access an entry in the pool | |
| virtual void | releaseResource (Data &d) |
| completes access to an entry in the pool, you must pass the same request instance here which you originally passed to useResource() | |
| void | doUseResource (Data &d) |
| does the actual work of useResource() | |
| void | doReleaseResource (Data &d) |
| does the actual work of releaseResource() | |
| void | InitAccess () |
| registers stateLookupMap with WorldState::setWorldStateLookup() | |
Protected Types | |
|
typedef ListMemBuf< unsigned int, NUM_STATES > | order_t |
| shorthand for the type of order | |
Protected Member Functions | |
| unsigned int | getCurrentReadState (WorldState *&tgt, bool block) |
| called when access to an entry for reading is requested | |
| void | doneReadingState (unsigned int i) |
| called when an read access to an entry is complete | |
| bool | isComplete (unsigned int idx) const |
| returns true if the specified element of states has been marked completed | |
| unsigned int | selectWriteState (unsigned int frame, bool block) const |
| returns index of buffer in states to use for write request | |
| unsigned int | selectWriteState (unsigned int frame, bool block, order_t::index_t &idx) const |
| returns index of buffer in states to use for write request, stores index of corresponding entry of order in idx | |
| unsigned int | getCurrentWriteState (WorldState *&tgt, unsigned int frame, bool block) |
| called when access to an entry for writing is requested | |
| void | doneWritingState (unsigned int i, bool completed) |
| called when an write access to an entry is complete | |
Static Protected Member Functions | |
| static bool | isZeroPID (WorldState *s, unsigned int i) |
| shorthand to test if all three P, I, and D values are 0 for the specified joint index (relative to 0, not PIDJointOffset) | |
Protected Attributes | |
| order_t | order |
| indicies of entries, in the order they were written (i.e. corresponding value in frames should be monotonically increasing) | |
| WorldState | states [NUM_STATES] |
| entries to hand out | |
| unsigned int | frames [NUM_STATES] |
| serial numbers of corresponding entries in states, set when writing begins, should be monotonically increasing relative to order (i.e. if you run through order and look at corresponding values in frames, should be monotonically increasing serial numbers) | |
| unsigned int | reading [NUM_STATES] |
| flag set when a reader is blocking for writing to finish, until read is satisified | |
| unsigned int | writing [NUM_STATES] |
| count of writers in line for access (occurs when a writer is blocking on another writer of the same frame, or no other frames are free) | |
| unsigned int | status [NUM_STATES] |
| the status is intended as a bitfield to support communication between writers if they need to cooperatively fill out an entry | |
| MutexLock< ProcessID::NumProcesses > | complete [NUM_STATES] |
| this lock indicates/controls whether the state is available for reading | |
| MutexLock< ProcessID::NumProcesses > | writeLocks [NUM_STATES] |
| locks to be acquired before handing out corresponding states entry for writing | |
| MutexLock< ProcessID::NumProcesses > | lock |
| lock on WorldStatePool's own members | |
| WorldState * | stateLookupMap [ProcessID::NumProcesses] |
| the current state in use by each process | |
Static Protected Attributes | |
| static const unsigned int | NUM_STATES = WORLDSTATEPOOL_NUM_STATES |
| number of buffers to set up | |
Private Member Functions | |
| WorldStatePool (const WorldStatePool &) | |
| this shouldn't be called... | |
| WorldStatePool & | operator= (const WorldStatePool &) |
| this shouldn't be called... | |
Classes | |
| class | ReadRequest |
| retrieves the current WorldState entry, and through it's destructor, marks the entry available again when it goes out of scope More... | |
| class | Request |
| class | UpdateInfo |
| returned by isUnread containing information parsed from the incoming message More... | |
| class | WriteRequest |
| retrieves the current WorldState entry, and through it's destructor, marks the entry available again when it goes out of scope More... | |
Member Function Documentation
| void WorldStatePool::doReleaseResource | ( | Data & | d | ) |
does the actual work of releaseResource()
this is split off as a non-virtual function to avoid some process identity issues that occur with virtual functions under Aperios
Definition at line 59 of file WorldStatePool.cc.
| void WorldStatePool::doUseResource | ( | Data & | d | ) |
does the actual work of useResource()
this is split off as a non-virtual function to avoid some process identity issues that occur with virtual functions under Aperios
Definition at line 33 of file WorldStatePool.cc.
| WorldStatePool::UpdateInfo * WorldStatePool::isUnread | ( | OSensorFrameVectorData & | msg, | |
| unsigned int & | lastFrameNumber | |||
| ) |
returns true if the process should call WorldState::read (i.e. msg has new or unprocessed data (such as motion needs to supply feedback))
only one call to this can be made at a time per process (not threadsafe, but is multi-process safe)
- Parameters:
-
msg the incoming sensor data from the system -- should be const, but accessor functions from Sony aren't marked const themselves :-/ [out] lastFrameNumber if the incoming frame is already complete (no need to read), then the frame's number will be assigned here
- Returns:
- returns a static UpdateInfo structure (to be passed to read()) if the message is unread, otherwise returns NULL. The structure is static -- DO NOT DELETE IT
Definition at line 93 of file WorldStatePool.cc.
Member Data Documentation
MutexLock<ProcessID::NumProcesses> WorldStatePool::complete[NUM_STATES] [protected] |
this lock indicates/controls whether the state is available for reading
The lock is set before handing out to a writer with a new frame number, and released when a writer has marked the entry complete (via the WriteRequest upon releaseResource())
Definition at line 243 of file WorldStatePool.h.
Referenced by doneWritingState(), getCurrentReadState(), getCurrentWriteState(), isComplete(), and WorldStatePool().
unsigned int WorldStatePool::status[NUM_STATES] [protected] |
the status is intended as a bitfield to support communication between writers if they need to cooperatively fill out an entry
The value is set to 0 before handing out to a writer with a new frame number
Definition at line 238 of file WorldStatePool.h.
Referenced by doReleaseResource(), doUseResource(), getCurrentWriteState(), and WorldStatePool().
The documentation for this class was generated from the following files:
