Index: src/platform/update_engine/delta_diff_generator.h |
diff --git a/src/platform/update_engine/delta_diff_generator.h b/src/platform/update_engine/delta_diff_generator.h |
index 6b232dad8ee557505cbd4ed7d5ef294d77dbcf07..6e48519380d575852aa734d9f0fbd99749298cc3 100644 |
--- a/src/platform/update_engine/delta_diff_generator.h |
+++ b/src/platform/update_engine/delta_diff_generator.h |
@@ -1,15 +1,111 @@ |
-// Copyright (c) 2009 The Chromium Authors. All rights reserved. |
+// Copyright (c) 2010 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_DELTA_DIFF_GENERATOR_H__ |
#define CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_DIFF_GENERATOR_H__ |
+#include <string> |
+#include <vector> |
#include "base/basictypes.h" |
+#include "update_engine/graph_types.h" |
+#include "update_engine/update_metadata.pb.h" |
+ |
+// There is one function in DeltaDiffGenerator of importance to users |
+// of the class: GenerateDeltaUpdateFile(). Before calling it, |
+// the old and new images must be mounted. Call GenerateDeltaUpdateFile() |
+// with both the mount-points of the images in addition to the paths of |
+// the images (both old and new). A delta from old to new will be |
+// generated and stored in output_path. |
namespace chromeos_update_engine { |
class DeltaDiffGenerator { |
+ public: |
+ // Represents a disk block on the install partition. |
+ struct Block { |
+ // During install, each block on the install partition will be written |
+ // and some may be read (in all likelihood, many will be read). |
+ // The reading and writing will be performed by InstallOperations, |
+ // each of which has a corresponding vertex in a graph. |
+ // A Block object tells which vertex will read or write this block |
+ // at install time. |
+ // Generally, there will be a vector of Block objects whose length |
+ // is the number of blocks on the install partition. |
+ Block() : reader(Vertex::kInvalidIndex), writer(Vertex::kInvalidIndex) {} |
+ Vertex::Index reader; |
+ Vertex::Index writer; |
+ }; |
+ |
+ // This is the only function that external users of the class should call. |
+ // old_image and new_image are paths to two image files. They should be |
+ // mounted read-only at paths old_root and new_root respectively. |
+ // output_path is the filename where the delta update should be written. |
+ // Returns true on success. |
+ static bool GenerateDeltaUpdateFile(const std::string& old_root, |
+ const std::string& old_image, |
+ const std::string& new_root, |
+ const std::string& new_image, |
+ const std::string& output_path); |
+ |
+ // These functions are public so that the unit tests can access them: |
+ |
+ // Reads old_filename (if it exists) and a new_filename and determines |
+ // the smallest way to encode this file for the diff. It stores |
+ // necessary data in out_data and fills in out_op. |
+ // If there's no change in old and new files, it creates a MOVE |
+ // operation. If there is a change, or the old file doesn't exist, |
+ // the smallest of REPLACE, REPLACE_BZ, or BSDIFF wins. |
+ // new_filename must contain at least one byte. |
+ // Returns true on success. |
+ static bool ReadFileToDiff(const std::string& old_filename, |
+ const std::string& new_filename, |
+ std::vector<char>* out_data, |
+ DeltaArchiveManifest_InstallOperation* out_op); |
+ |
+ // Modifies blocks read by 'op' so that any blocks referred to by |
+ // 'remove_extents' are replaced with blocks from 'replace_extents'. |
+ // 'remove_extents' and 'replace_extents' must be the same number of blocks. |
+ // Blocks will be substituted in the order listed in the vectors. |
+ // E.g. if 'op' reads blocks 1, 2, 3, 4, 5, 6, 7, 8, remove_extents |
+ // contains blocks 6, 2, 3, 5, and replace blocks contains |
+ // 12, 13, 14, 15, then op will be changed to read from: |
+ // 1, 13, 14, 4, 15, 12, 7, 8 |
+ static void SubstituteBlocks(DeltaArchiveManifest_InstallOperation* op, |
+ const std::vector<Extent>& remove_extents, |
+ const std::vector<Extent>& replace_extents); |
+ |
+ // Cuts 'edges' from 'graph' according to the AU algorithm. This means |
+ // for each edge A->B, remove the dependency that B occur before A. |
+ // Do this by creating a new operation X that copies from the blocks |
+ // specified by the edge's properties to temp space T. Modify B to read |
+ // from T rather than the blocks in the edge. Modify A to depend on X, |
+ // but not on B. Free space is found by looking in 'blocks'. |
+ // Returns true on success. |
+ static bool CutEdges(Graph* graph, |
+ const std::vector<Block>& blocks, |
+ const std::set<Edge>& edges); |
+ |
+ // Stores all Extents in 'extents' into 'out'. |
+ static void StoreExtents(std::vector<Extent>& extents, |
+ google::protobuf::RepeatedPtrField<Extent>* out); |
+ |
+ // Creates all the edges for the graph. Writers of a block point to |
+ // readers of the same block. This is because for an edge A->B, B |
+ // must complete before A executes. |
+ static void CreateEdges(Graph* graph, const std::vector<Block>& blocks); |
+ |
+ // Install operations in the manifest may reference data blobs, which |
+ // are in data_blobs_path. This function creates a new data blobs file |
+ // with the data blobs in the same order as the referencing install |
+ // operations in the manifest. E.g. if manifest[0] has a data blob |
+ // "X" at offset 1, manifest[1] has a data blob "Y" at offset 0, |
+ // and data_blobs_path's file contains "YX", new_data_blobs_path |
+ // will set to be a file that contains "XY". |
+ static bool ReorderDataBlobs(DeltaArchiveManifest* manifest, |
+ const std::string& data_blobs_path, |
+ const std::string& new_data_blobs_path); |
+ |
private: |
// This should never be constructed |
DISALLOW_IMPLICIT_CONSTRUCTORS(DeltaDiffGenerator); |