AU: More graph utilities

graph_types.h

 // 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.
 
 #ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_GRAPH_TYPES_H__
 #define CHROMEOS_PLATFORM_UPDATE_ENGINE_GRAPH_TYPES_H__
 
 #include <map>
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
 #include "base/basictypes.h"
 #include "update_engine/update_metadata.pb.h"
 
 // A few classes that help in generating delta images use these types
 // for the graph work.
 
 namespace chromeos_update_engine {
 
+bool operator==(const Extent& a, const Extent& b);
+
 struct EdgeProperties {
-  std::vector<Extent> extents;  // filesystem extents represented
+  // Read-before extents. I.e., blocks in |extents| must be read by the
+  // node pointed to before the pointing node runs (presumably b/c it
+  // overwrites these blocks).
+  std::vector<Extent> extents;
+  
+  // Write before extents. I.e., blocks in |write_extents| must be written
+  // by the node pointed to before the pointing node runs (presumably
+  // b/c it reads the data written by the other node).
+  std::vector<Extent> write_extents;
+  
+  bool operator==(const EdgeProperties& that) const {
+    return extents == that.extents && write_extents == that.write_extents;
+  }
 };
 
 struct Vertex {
-  Vertex() : index(-1), lowlink(-1) {}
+  Vertex() : valid(true), index(-1), lowlink(-1) {}
+  bool valid;
+  
   typedef std::map<std::vector<Vertex>::size_type, EdgeProperties> EdgeMap;
   EdgeMap out_edges;
 
   // We sometimes wish to consider a subgraph of a graph. A subgraph would have
   // a subset of the vertices from the graph and a subset of the edges.
   // When considering this vertex within a subgraph, subgraph_edges stores
   // the out-edges.
   typedef std::set<std::vector<Vertex>::size_type> SubgraphEdgeMap;
   SubgraphEdgeMap subgraph_edges;
 
   // For Tarjan's algorithm:
   std::vector<Vertex>::size_type index;
   std::vector<Vertex>::size_type lowlink;
 
   // Other Vertex properties:
   DeltaArchiveManifest_InstallOperation op;
   std::string file_name;
 
   typedef std::vector<Vertex>::size_type Index;
   static const Vertex::Index kInvalidIndex = -1;
 };
 
 typedef std::vector<Vertex> Graph;
 
 typedef std::pair<Vertex::Index, Vertex::Index> Edge;
 
 const uint64_t kSparseHole = kuint64max;
+const uint64_t kTempBlockStart = 1ULL << 60;
+COMPILE_ASSERT(kTempBlockStart != 0, kTempBlockStart_invalid);
 
 }  // namespace chromeos_update_engine
 
 #endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_GRAPH_TYPES_H__