/* NODEINVOCATION.hpp - Organize the invocation state within a single pull() call Copyright (C) Lumiera.org 2008, Hermann Vosseler This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ /** @file nodeinvocation.hpp ** Organize the state related to the invocation of s single ProcNode::pull() call ** This header defines part of the "glue" which holds together the render node network ** and enables to pull result frames from the nodes. Doing so requires some invocation ** local state to be maintained, especially a table of buffers used to carry out the ** calculations. Further, getting the input buffers filled requires to issue recursive ** \c pull() calls, which on the whole creates a stack-like assembly of local invocation ** state. ** The actual steps to be carried out for a \c pull() call are dependant on the configuration ** of the node to pull. Each node has been preconfigured by the builder with a WiringDescriptor ** and a concrete type of a StateAdapter. The actual sequence of steps is defined in the header ** nodeoperation.hpp out of a set of basic operation steps. These steps all use the passed in ** Invocation object (a sub-interface of StateAdapter) to access the various aspects of the ** invocation state. ** ** \par composition of the Invocation State ** For each individual ProcNode#pull() call, the WiringAdapter#callDown() builds an StateAdapter ** instance directly on the stack, managing the actual buffer pointers and state references. Using this ** StateAdapter, the predecessor nodes are pulled. The way these operations are carried out is encoded ** in the actual StateAdapter type known to the NodeWiring (WiringAdapter) instance. All of these actual ** StateAdapter types are built as implementing the engine::State interface. ** ** @see engine::ProcNode ** @see engine::StateProxy ** @see engine::BuffTable ** @see nodewiring.hpp interface for building/wiring the nodes ** */ #ifndef ENGINE_NODEINVOCATION_H #define ENGINE_NODEINVOCATION_H #include "proc/state.hpp" #include "proc/engine/procnode.hpp" #include "proc/engine/buffhandle.hpp" #include "proc/engine/bufftable.hpp" namespace engine { /** * Adapter to shield the ProcNode from the actual buffer management, * allowing the processing function within ProcNode to use logical * buffer IDs. StateAdapter is created on the stack for each pull() * call, using setup/wiring data preconfigured by the builder. * Its job is to provide the actual implementation of the Cache * push / fetch and recursive downcall to render the source frames. */ class StateAdapter : public State { protected: State& parent_; State& current_; StateAdapter (State& callingProcess) : parent_ (callingProcess), current_(callingProcess.getCurrentImplementation()) { } virtual State& getCurrentImplementation () { return current_; } public: /* === proxying the State interface === */ virtual void releaseBuffer (BuffHandle& bh) { current_.releaseBuffer (bh); } virtual void is_calculated (BuffHandle const& bh) { current_.is_calculated (bh); } virtual BuffHandle fetch (FrameID const& fID) { return current_.fetch (fID); } // note: allocateBuffer() is chosen specifically based on the actual node wiring }; /** * Invocation context state. * A ref to this type is carried through the chain of NEXT::step() functions * which form the actual invocation sequence. The various operations in this sequence * access the context via the references in this struct, while also using the inherited * public State interface. The object instance actually used as Invocation is created * on the stack and parametrised according to the necessities of the invocation sequence * actually configured. Initially, this real instance is configured without BuffTable, * because the invocation may be short-circuited due to Cache hit. Otherwise, when * the invocation sequence actually prepares to call the process function of this * ProcNode, a buffer table chunk is allocated by the StateProxy and wired in. */ struct Invocation : StateAdapter { WiringDescriptor const& wiring; const uint outNr; BuffTable* buffTab; protected: /** creates a new invocation context state, without BuffTable */ Invocation (State& callingProcess, WiringDescriptor const& w, uint o) : StateAdapter(callingProcess), wiring(w), outNr(o), buffTab(0) { } const uint nrO() const { return wiring.getNrO(); } const uint nrI() const { return wiring.getNrI(); } const uint buffTabSize() const { return nrO()+nrI(); } /** setup the link to an externally allocated buffer table */ void setBuffTab (BuffTable* b) { this->buffTab = b; } bool buffTab_isConsistent () { return (buffTab) && (0 < buffTabSize()) && (nrO()+nrI() <= buffTabSize()) && (buffTab->inBuff == &buffTab->outBuff[nrO()] ) && (buffTab->inHandle == &buffTab->outHandle[nrO()]) ; } }; struct AllocBufferFromParent ///< using the parent StateAdapter for buffer allocations : Invocation { AllocBufferFromParent (State& sta, WiringDescriptor const& w, const uint outCh) : Invocation(sta, w, outCh) {} virtual BuffHandle allocateBuffer (BufferDescriptor const& bd) { return parent_.allocateBuffer(bd); } }; struct AllocBufferFromCache ///< using the global current State, which will delegate to Cache : Invocation { AllocBufferFromCache (State& sta, WiringDescriptor const& w, const uint outCh) : Invocation(sta, w, outCh) {} virtual BuffHandle allocateBuffer (BufferDescriptor const& bd) { return current_.allocateBuffer(bd); } }; /** * The real invocation context state implementation. It is created * by the NodeWiring (WiringDescriptor) of the processing node which * is pulled by this invocation, hereby using the internal configuration * information to guide the selecton of the real call sequence * * \par assembling the call sequence implementation * Each ProcNode#pull() call creates such a StateAdapter subclass on the stack, * with a concrete type according to the WiringDescriptor of the node to pull. * This concrete type encodes a calculation Strategy, which is assembled * as a chain of policy templates on top of OperationBase. For each of the * possible configuratons we define such a chain (see bottom of nodeoperation.hpp). * The WiringFactory defined in nodewiring.cpp actually drives the instantiation * of all those possible combinations. */ template class ActualInvocationProcess : public BufferProvider { public: ActualInvocationProcess (State& callingProcess, WiringDescriptor const& w, const uint outCh) : BufferProvider(callingProcess, w, outCh) { } /** contains the details of Cache query and recursive calls * to the predecessor node(s), eventually followed by the * ProcNode::process() callback */ BuffHandle retrieve () { return Strategy::step (*this); } }; } // namespace engine #endif