Differential updates for components.

chrome/browser/component_updater/component_patcher.cc

+// 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.
+
+#include "chrome/browser/component_updater/component_patcher.h"
+
+#include <string>
+#include <vector>
+
+#include "base/file_util.h"
+#include "base/json/json_file_value_serializer.h"
+#include "base/values.h"
+#include "chrome/browser/component_updater/component_patcher_operation.h"
+#include "chrome/browser/component_updater/component_updater_service.h"
+
+namespace {
+
+// Deserialize the commands file (present in delta update packages). The top
+// level must be a list.
+base::ListValue* ReadCommands(const base::FilePath& unpack_path) {
+  const base::FilePath commands =
+      unpack_path.Append(FILE_PATH_LITERAL("commands.json"));
+  if (!file_util::PathExists(commands))
+    return NULL;
+
+  JSONFileValueSerializer serializer(commands);
+  scoped_ptr<base::Value> root(serializer.Deserialize(NULL, NULL));
+
+  return (root.get() && root->IsType(base::Value::TYPE_LIST)) ?
+      static_cast<base::ListValue*>(root.release()) : NULL;
+}
+
+}  // namespace
+
+
+// The patching support is not cross-platform at the moment.
+ComponentPatcherCrossPlatform::ComponentPatcherCrossPlatform() {}
+
+ComponentUnpacker::Error ComponentPatcherCrossPlatform::Patch(
+    PatchType patch_type,
+    const base::FilePath& input_file,
+    const base::FilePath& patch_file,
+    const base::FilePath& output_file,
+    int* error) {
+  return ComponentUnpacker::kDeltaUnsupportedCommand;
+}
+
+
+// Takes the contents of a differential component update in input_dir
+// and produces the contents of a full component update in unpack_dir
+// using input_abs_path_ files that the installer knows about.
+ComponentUnpacker::Error DifferentialUpdatePatch(
+    const base::FilePath& input_dir,
+    const base::FilePath& unpack_dir,
+    ComponentPatcher* patcher,
+    ComponentInstaller* installer,
+    int* error) {
+  *error = 0;
+  scoped_ptr<base::ListValue> commands(ReadCommands(input_dir));
+  if (!commands.get())
+    return ComponentUnpacker::kDeltaBadCommands;
+
+  for (base::ValueVector::const_iterator command = commands->begin(),
+      end = commands->end(); command != end; command++) {
+    if (!(*command)->IsType(base::Value::TYPE_DICTIONARY))
+      return ComponentUnpacker::kDeltaBadCommands;
+    base::DictionaryValue* command_args =
+        static_cast<base::DictionaryValue*>(*command);
+    scoped_ptr<DeltaUpdateOp> operation(CreateDeltaUpdateOp(command_args));
+    if (!operation)
+      return ComponentUnpacker::kDeltaUnsupportedCommand;
+
+    ComponentUnpacker::Error result = operation->Run(
+        command_args, input_dir, unpack_dir, patcher, installer, error);
+    if (result != ComponentUnpacker::kNone)
+      return result;
+  }
+
+  return ComponentUnpacker::kNone;
+}
+