AU: Some graph types and a couple utility functions
These will be used by the delta diff generator.
Review URL: http://codereview.chromium.org/578009
diff --git a/SConstruct b/SConstruct
index 38ae3f1..0f600a2 100644
--- a/SConstruct
+++ b/SConstruct
@@ -93,6 +93,7 @@
filesystem_copier_action.cc
filesystem_iterator.cc
file_writer.cc
+ graph_utils.cc
gzip.cc
libcurl_http_fetcher.cc
omaha_hash_calculator.cc
@@ -117,6 +118,7 @@
file_writer_unittest.cc
filesystem_copier_action_unittest.cc
filesystem_iterator_unittest.cc
+ graph_utils_unittest.cc
gzip_unittest.cc
http_fetcher_unittest.cc
mock_http_fetcher.cc
diff --git a/graph_types.h b/graph_types.h
new file mode 100644
index 0000000..afb7f64
--- /dev/null
+++ b/graph_types.h
@@ -0,0 +1,53 @@
+// 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 <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 {
+
+struct EdgeProperties {
+ std::vector<Extent> extents; // filesystem extents represented
+};
+
+struct Vertex {
+ Vertex() : index(-1), lowlink(-1), op(NULL) {}
+ 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;
+
+ 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;
+
+} // namespace chromeos_update_engine
+
+#endif // CHROMEOS_PLATFORM_UPDATE_ENGINE_GRAPH_TYPES_H__
diff --git a/graph_utils.cc b/graph_utils.cc
new file mode 100644
index 0000000..79d5733
--- /dev/null
+++ b/graph_utils.cc
@@ -0,0 +1,41 @@
+// 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 "update_engine/graph_utils.h"
+#include "base/basictypes.h"
+
+using std::vector;
+
+namespace chromeos_update_engine {
+
+namespace graph_utils {
+
+uint64 EdgeWeight(const Graph& graph, const Edge& edge) {
+ uint64 weight = 0;
+ const vector<Extent>& extents =
+ graph[edge.first].out_edges.find(edge.second)->second.extents;
+ for (vector<Extent>::const_iterator it = extents.begin();
+ it != extents.end(); ++it) {
+ weight += it->num_blocks();
+ }
+ return weight;
+}
+
+void AppendBlockToExtents(vector<Extent>* extents, uint64 block) {
+ if (!extents->empty()) {
+ Extent& extent = extents->back();
+ if (extent.start_block() + extent.num_blocks() == block) {
+ extent.set_num_blocks(extent.num_blocks() + 1);
+ return;
+ }
+ }
+ Extent new_extent;
+ new_extent.set_start_block(block);
+ new_extent.set_num_blocks(1);
+ extents->push_back(new_extent);
+}
+
+} // namespace graph_utils
+
+} // namespace chromeos_update_engine
diff --git a/graph_utils.h b/graph_utils.h
new file mode 100644
index 0000000..62ecfd5
--- /dev/null
+++ b/graph_utils.h
@@ -0,0 +1,31 @@
+// 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_UTILS_H__
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_GRAPH_UTILS_H__
+
+#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 EdgeWeight(const Graph& graph, const Edge& edge);
+
+// 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 block);
+
+} // namespace graph_utils
+
+} // namespace chromeos_update_engine
+
+#endif // CHROMEOS_PLATFORM_UPDATE_ENGINE_GRAPH_UTILS_H__
diff --git a/graph_utils_unittest.cc b/graph_utils_unittest.cc
new file mode 100644
index 0000000..d947ddd
--- /dev/null
+++ b/graph_utils_unittest.cc
@@ -0,0 +1,41 @@
+// Copyright (c) 2009 The Chromium OS 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 <utility>
+#include <vector>
+#include <gtest/gtest.h>
+#include "update_engine/graph_utils.h"
+
+using std::make_pair;
+using std::vector;
+
+namespace chromeos_update_engine {
+
+class GraphUtilsTest : public ::testing::Test {};
+
+TEST(GraphUtilsTest, SimpleTest) {
+ Graph graph(2);
+
+ graph[0].out_edges.insert(make_pair(1, EdgeProperties()));
+
+ vector<Extent>& extents = graph[0].out_edges[1].extents;
+
+ EXPECT_EQ(0, extents.size());
+ graph_utils::AppendBlockToExtents(&extents, 0);
+ EXPECT_EQ(1, extents.size());
+ graph_utils::AppendBlockToExtents(&extents, 1);
+ graph_utils::AppendBlockToExtents(&extents, 2);
+ EXPECT_EQ(1, extents.size());
+ graph_utils::AppendBlockToExtents(&extents, 4);
+
+ EXPECT_EQ(2, extents.size());
+ EXPECT_EQ(0, extents[0].start_block());
+ EXPECT_EQ(3, extents[0].num_blocks());
+ EXPECT_EQ(4, extents[1].start_block());
+ EXPECT_EQ(1, extents[1].num_blocks());
+
+ EXPECT_EQ(4, graph_utils::EdgeWeight(graph, make_pair(0, 1)));
+}
+
+} // namespace chromeos_update_engine
diff --git a/utils.h b/utils.h
index de998f4..9354ba5 100644
--- a/utils.h
+++ b/utils.h
@@ -80,6 +80,11 @@
return ret;
}
+template<typename T>
+bool VectorContainsValue(const std::vector<T>& vect, const T& value) {
+ return std::find(vect.begin(), vect.end(), value) != vect.end();
+}
+
// Returns the currently booted device. "/dev/sda1", for example.
// This will not interpret LABEL= or UUID=. You'll need to use findfs
// or something with equivalent funcionality to interpret those.