Differential updates for components.

chrome/browser/component_updater/component_patcher_internal.h

+// Copyright (c) 2013 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 CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_PATCHER_INTERNAL_H_
+#define CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_PATCHER_INTERNAL_H_
+
+#include <string>
+#include "base/basictypes.h"
+#include "base/files/file_path.h"
+#include "base/values.h"

[cpu_(ooo_6.6-7.5), 2013/05/29 20:06:44]

I am guessing the you can fwd declare Value instead.

[waffles, 2013/06/13 20:55:04]

Done.

+#include "chrome/browser/component_updater/component_patcher.h"
+
+class ComponentInstaller;
+
+class DeltaUpdateOp {
+ public:
+  // These constants refer to the position of arguments in the command list.
+  enum ArgumentPos {
+    kDeltaOutputPath = 0,
+    kDeltaOutputSha256 = 1,
+    kDeltaOperation = 2,
+  };
+
+  DeltaUpdateOp();
+  virtual ~DeltaUpdateOp();
+
+  // Parses, runs, and verifies the operation, returning an error code if an
+  // error is encountered, and DELTA_OK otherwise. In case of errors,
+  // extended error information can be returned in the |error| parameter.
+  DeltaUpdateResult Run(
+      base::ListValue* command_args,
+      const base::FilePath& input_dir,
+      const base::FilePath& unpack_dir,
+      ComponentPatcher* patcher,
+      ComponentInstaller* installer,
+      int* error);
+
+ protected:
+  std::string output_sha256_;       // The SHA-256 hash of the output file.
+  base::FilePath output_abs_path_;  // The relative location for the output.

[cpu_(ooo_6.6-7.5), 2013/05/29 20:06:44]

prefer comments above each line. In this particular case the second comment
seems superfluous and misleading since the name has 'abs' and the comment says
relative.

Please give a pass to all the comments, we like more of a commentary on the
contract of the methods (like in lines 28 - 30) than on individual variables and
such.

[waffles, 2013/06/13 20:55:04]

Done.

+
+ private:
+  DeltaUpdateResult CheckHash();
+
+  // Subclasses must override DoParseArguments to parse operation-specific
+  // arguments. DoParseArguments returns DELTA_OK on success; any other code
+  // represents failure.
+  virtual DeltaUpdateResult DoParseArguments(base::ListValue* command_args,
+                                             const base::FilePath& input_dir,
+                                             ComponentInstaller* installer) = 0;
+
+  // Subclasses must override DoRun to actually perform the patching operation.
+  // DoRun returns DELTA_OK on success; any other code represents failure.
+  // Additional error information can be returned in the |error| parameter.
+  virtual DeltaUpdateResult DoRun(ComponentPatcher* patcher, int* error) = 0;
+
+  DISALLOW_COPY_AND_ASSIGN(DeltaUpdateOp);
+};
+
+// A 'copy' operation takes a file currently residing on the disk and moves it
+// into the unpacking directory: this represents "no change" in the file being
+// installed.
+class DeltaUpdateOpCopy : public DeltaUpdateOp {
+ public:

[cpu_(ooo_6.6-7.5), 2013/05/29 20:06:44]

since DeltaUpdateOp::ArgumentPos is in scope here having
DeltaUpdateOpCopy::ArgumentPos makes the code hard to read for me, is there any
particular advantage to this arrangement?

[waffles, 2013/06/13 20:55:04]

Done.

+  enum ArgumentPos {
+    kDeltaFrom = 3,
+  };
+
+  DeltaUpdateOpCopy();
+
+ private:
+  // Overrides of DeltaUpdateOp.
+  virtual DeltaUpdateResult DoParseArguments(
+      base::ListValue* command_args,
+      const base::FilePath& input_dir,
+      ComponentInstaller* installer) OVERRIDE;
+
+  virtual DeltaUpdateResult DoRun(ComponentPatcher* patcher,
+                                  int* error) OVERRIDE;
+
+  base::FilePath input_abs_path_;
+
+  DISALLOW_COPY_AND_ASSIGN(DeltaUpdateOpCopy);
+};
+
+// A 'create' operation takes a full file that was sent in the delta update
+// archive and moves it into the unpacking directory: this represents the
+// addition of a new file, or a file so different that no bandwidth could be
+// saved by transmitting a differential update.
+class DeltaUpdateOpCreate : public DeltaUpdateOp {
+ public:
+  enum ArgumentPos {
+    kDeltaPatch = 3,
+  };
+
+  DeltaUpdateOpCreate();
+
+ private:
+  // Overrides of DeltaUpdateOp.
+  virtual DeltaUpdateResult DoParseArguments(
+      base::ListValue* command_args,
+      const base::FilePath& input_dir,
+      ComponentInstaller* installer) OVERRIDE;
+
+  virtual DeltaUpdateResult DoRun(ComponentPatcher* patcher,
+                                  int* error) OVERRIDE;
+
+  base::FilePath patch_abs_path_;
+
+  DISALLOW_COPY_AND_ASSIGN(DeltaUpdateOpCreate);
+};
+
+// A 'bsdiff' operation takes an existing file on disk, and a bsdiff-
+// format patch file provided in the delta update package, and runs bsdiff
+// to construct an output file in the unpacking directory.
+class DeltaUpdateOpPatchBsdiff : public DeltaUpdateOp {
+ public:
+  enum ArgumentPos {
+    kDeltaFrom = 3,
+    kDeltaPatch = 4,
+  };
+
+  DeltaUpdateOpPatchBsdiff();
+
+ private:
+  // Overrides of DeltaUpdateOp.
+  virtual DeltaUpdateResult DoParseArguments(
+      base::ListValue* command_args,
+      const base::FilePath& input_dir,
+      ComponentInstaller* installer) OVERRIDE;
+
+  virtual DeltaUpdateResult DoRun(ComponentPatcher* patcher,
+                                  int* error) OVERRIDE;
+
+  base::FilePath patch_abs_path_;
+  base::FilePath input_abs_path_;
+
+  DISALLOW_COPY_AND_ASSIGN(DeltaUpdateOpPatchBsdiff);
+};
+
+// A 'courgette' operation takes an existing file on disk, and a Courgette-
+// format patch file provided in the delta update package, and runs Courgette
+// to construct an output file in the unpacking directory.
+class DeltaUpdateOpPatchCourgette : public DeltaUpdateOp {
+ public:
+  enum ArgumentPos {
+    kDeltaFrom = 3,
+    kDeltaPatch = 4,
+  };
+
+  DeltaUpdateOpPatchCourgette();
+
+ private:
+  // Overrides of DeltaUpdateOp.
+  virtual DeltaUpdateResult DoParseArguments(
+      base::ListValue* command_args,
+      const base::FilePath& input_dir,
+      ComponentInstaller* installer) OVERRIDE;
+
+  virtual DeltaUpdateResult DoRun(ComponentPatcher* patcher,
+                                  int* error) OVERRIDE;
+
+  base::FilePath patch_abs_path_;
+  base::FilePath input_abs_path_;
+
+  DISALLOW_COPY_AND_ASSIGN(DeltaUpdateOpPatchCourgette);
+};
+
+#endif  // CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_PATCHER_INTERNAL_H_
+