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// Copyright (c) 2009 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <vector>
#include "base/basictypes.h"
#include "update_engine/graph_types.h"
#include "update_engine/update_metadata.pb.h"
// A few utility functions for graphs
namespace chromeos_update_engine {
namespace graph_utils {
// Returns the number of blocks represented by all extents in the edge.
uint64_t EdgeWeight(const Graph& graph, const Edge& edge);
// These add a read-before dependency from graph[src] -> graph[dst]. If the dep
// already exists, the block/s is/are added to the existing edge.
void AddReadBeforeDep(Vertex* src,
Vertex::Index dst,
uint64_t block);
void AddReadBeforeDepExtents(Vertex* src,
Vertex::Index dst,
const std::vector<Extent>& extents);
void DropWriteBeforeDeps(Vertex::EdgeMap* edge_map);
// For each node N in graph, drop all edges N->|index|.
void DropIncomingEdgesTo(Graph* graph, Vertex::Index index);
// block must either be the next block in the last extent or a block
// in the next extent. This function will not handle inserting block
// into an arbitrary place in the extents.
void AppendBlockToExtents(std::vector<Extent>* extents, uint64_t block);
// Get/SetElement are intentionally overloaded so that templated functions
// can accept either type of collection of Extents.
Extent GetElement(const std::vector<Extent>& collection, size_t index);
Extent GetElement(
const google::protobuf::RepeatedPtrField<Extent>& collection,
size_t index);
template<typename T>
uint64_t BlocksInExtents(const T& collection) {
uint64_t ret = 0;
for (size_t i = 0; i < static_cast<size_t>(collection.size()); ++i) {
ret += GetElement(collection, i).num_blocks();
return ret;
void DumpGraph(const Graph& graph);
} // namespace graph_utils
} // namespace chromeos_update_engine