networkUtil.h

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//
// Copyright 2025 Pixar
//
// Licensed under the terms set forth in the LICENSE.txt file available at
// https://openusd.org/license.
//
#ifndef PXR_EXEC_VDF_NETWORK_UTIL_H
#define PXR_EXEC_VDF_NETWORK_UTIL_H
 
 
#include "pxr/pxr.h"
 
#include "pxr/exec/vdf/api.h"
#include "pxr/exec/vdf/connection.h"
#include "pxr/exec/vdf/input.h"
#include "pxr/exec/vdf/network.h"
#include "pxr/exec/vdf/node.h"
#include "pxr/exec/vdf/types.h"
 
#include "pxr/base/tf/token.h"
 
PXR_NAMESPACE_OPEN_SCOPE
 
class VdfMaskedOutput;
class VdfOutput;
 
 
 
VDF_API
bool VdfIsSpeculating(const VdfMaskedOutput &maskedOutput);
 
VDF_API
bool VdfIsTopologicalSourceNode(
    const VdfNode &startNode,
    const VdfNode &nodeToFind,
    bool *foundSpecNode = nullptr);
 
VDF_API
const VdfOutput *VdfGetAssociatedSourceOutput(const VdfOutput &output);
 
VDF_API
void VdfEmptyNodeCallback(const VdfNode &);
 
template <class Callable>
void VdfTraverseTopologicalSourceNodes(
    const VdfNode &startNode, 
    Callable &&callback)
{
    // Keep track of the nodes we have already visited.
    TfBits visited(startNode.GetNetwork().GetNodeCapacity());
 
    // Maintain a stack of nodes to traverse.
    std::vector<const VdfNode *> stack(1, &startNode);
 
    // Keep traversing as long as there are entries on the stack.
    while (!stack.empty()) {
 
        // The stack top is the node we are currently looking at.
        const VdfNode *top = stack.back();
        stack.pop_back();
 
        // Only consider this node, if it hasn't already been visited.
        const VdfIndex idx = VdfNode::GetIndexFromId(top->GetId());
        if (visited.IsSet(idx)) {
            continue;
        }
        visited.Set(idx);
 
        // Invoke the callback for the node, and push the input dependencies
        // on the stack, as long as the callback returns true.
        if (std::forward<Callable>(callback)(*top)) {
            for (const std::pair<TfToken, VdfInput *> &i :
                    top->GetInputsIterator()) {
                for (const VdfConnection *c : i.second->GetConnections()) {
                    stack.push_back(&c->GetSourceNode());
                }
            }
        }
    }
}
 
 
PXR_NAMESPACE_CLOSE_SCOPE
 
#endif