FileTypePolicies class to load types from proto.

chrome/common/safe_browsing/file_type_policies.h

+// Copyright 2016 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_COMMON_SAFE_BROWSING_FILE_TYPE_POLICIES_H_
+#define CHROME_COMMON_SAFE_BROWSING_FILE_TYPE_POLICIES_H_
+
+#include <map>
+#include <memory>
+
+#include "base/files/file_path.h"
+#include "base/gtest_prod_util.h"
+#include "chrome/common/safe_browsing/download_file_types.pb.h"
+
+namespace safe_browsing {
+
+// This holds a list of file types (aka file extensions) that we know about,
+// with policies related to how Safe Browsing and the download UI should treat
+// them.
+//
+// The data to populate it is read from a ResourceBundle and then also
+// fetched periodically from Google to get the most up-to-date policies.
+//
+// It should be setup and accessed on IO thread.
+
+// TODO(nparker): Replace the following methods' contents with calls to
+//   g_browser_process->safe_browsing_service()->file_type_policies()->***.
+//
+//   bool IsSupportedBinaryFile(const base::FilePath& file);
+//   bool IsArchiveFile(const base::FilePath& file);
+//   ClientDownloadRequest::DownloadType GetDownloadType(
+//       const base::FilePath& file);
+//   int GetSBClientDownloadTypeValueForUMA(const base::FilePath& file);
+//   bool IsAllowedToOpenAutomatically(const base::FilePath& path);
+//   DownloadDangerLevel GetFileDangerLevel(const base::FilePath& path);
+
+class FileTypePolicies {
+ public:
+  // Creator must call one of Populate* before calling other methods.
+  FileTypePolicies();
+  virtual ~FileTypePolicies();
+
+  // Read data from the main ResourceBundle. This updates the internal list
+  // only if the data passes integrity checks. This is normally called once
+  // after construction.
+  void PopulateFromResourceBundle();
+
+  // Update the internal list from a binary proto fetched from the network.
+  // Same integrity checks apply. This can be called multiple times with new
+  // protos.
+  void PopulateFromDynamicUpdate(const std::string& binary_pb);
+
+  // Accessors
+  const DownloadFileType& PolicyForFile(const base::FilePath& file);
+  const DownloadFileType::PlatformSettings& SettingsForFile(
+      const base::FilePath& file);
+  int64_t UmaValueForFile(const base::FilePath& file);
+  bool IsFileAnArchive(const base::FilePath& file);
+  float SampledPingProbability() const;
+
+ protected:
+  // Used in metrics, do not reorder.
+  enum class UpdateResult {
+    SUCCESS = 1,
+    FAILED_EMPTY = 2,
+    FAILED_PROTO_PARSE = 3,
+    FAILED_DELTA_CHECK = 4,
+    FAILED_VERSION_CHECK = 5,
+    FAILED_DEFAULT_SETTING_SET = 6,
+    FAILED_WRONG_SETTINGS_COUNT = 7,
+  };
+
+  // Read data from an serialized protobuf and update the internal list
+  // only if it passes integrity checks.
+  virtual UpdateResult PopulateFromBinaryPb(const std::string& binary_pb);
+
+  // Fetch the blob from the main resource bundle.
+  virtual void ReadResourceBundle(std::string* binary_pb);
+
+  // Record the result of an update attempt.
+  virtual void RecordUpdateMetrics(UpdateResult result,
+                                   const std::string& src_name);
+
+  // Return the ASCII lowercase extension w/o leading dot, or empty.
+  static std::string CanonicalizedExtension(const base::FilePath& file);
+
+ private:
+  // The latest config we've committed. Starts out null.
+  std::unique_ptr<DownloadFileTypeConfig> config_;
+
+  // This references entries in config_.
+  std::map<std::string, const DownloadFileType*> file_type_by_ext_;
+
+  // Type used if we can't load from disk.
+  DownloadFileType last_resort_default_;
+
+  FRIEND_TEST_ALL_PREFIXES(FileTypePoliciesTest, UnpackResourceBundle);
+  FRIEND_TEST_ALL_PREFIXES(FileTypePoliciesTest, BadProto);
+  FRIEND_TEST_ALL_PREFIXES(FileTypePoliciesTest, BadUpdateFromExisting);
+};
+
+}  // namespace safe_browsing
+
+#endif  // CHROME_COMMON_SAFE_BROWSING_FILE_TYPE_POLICIES_H_