extensions/browser/api/declarative_net_request/ruleset_matcher_base.h

// Copyright 2019 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 EXTENSIONS_BROWSER_API_DECLARATIVE_NET_REQUEST_RULESET_MATCHER_BASE_H_
#define EXTENSIONS_BROWSER_API_DECLARATIVE_NET_REQUEST_RULESET_MATCHER_BASE_H_

#include <map>
#include <vector>

#include "base/optional.h"
#include "content/public/browser/global_routing_id.h"
#include "extensions/browser/api/declarative_net_request/flat/extension_ruleset_generated.h"
#include "extensions/browser/api/declarative_net_request/request_action.h"
#include "extensions/common/api/declarative_net_request.h"
#include "extensions/common/extension_id.h"

class GURL;

namespace content {
class RenderFrameHost;
}  // namespace content

namespace extensions {

namespace declarative_net_request {
struct RequestParams;

// An abstract class for rule matchers. Overridden by different kinds of
// matchers, e.g. filter lists and regex.
class RulesetMatcherBase {
 public:
  RulesetMatcherBase(const ExtensionId& extension_id,
                     api::declarative_net_request::SourceType source_type);

  virtual ~RulesetMatcherBase();

  // Returns the ruleset's highest priority matching RequestAction for the
  // onBeforeRequest phase, or base::nullopt if the ruleset has no matching
  // rule. Also takes into account any matching allowAllRequests rules for the
  // ancestor frames.
  base::Optional<RequestAction> GetBeforeRequestAction(
      const RequestParams& params) const;

  // Returns the bitmask of headers to remove from the request. The bitmask
  // corresponds to flat::RemoveHeaderType. |excluded_remove_headers_mask|
  // denotes the mask of headers to be skipped for evaluation and is excluded in
  // the return value.
  virtual uint8_t GetRemoveHeadersMask(
      const RequestParams& params,
      uint8_t excluded_remove_headers_mask,
      std::vector<RequestAction>* remove_headers_actions) const = 0;

  // Returns whether this modifies "extraHeaders".
  virtual bool IsExtraHeadersMatcher() const = 0;

  // Returns the number of rules in this matcher.
  virtual size_t GetRulesCount() const = 0;

  // Returns the extension ID with which this matcher is associated.
  const ExtensionId& extension_id() const { return extension_id_; }

  // The source type of the matcher.
  api::declarative_net_request::SourceType source_type() const {
    return source_type_;
  }

  void OnRenderFrameCreated(content::RenderFrameHost* host);
  void OnRenderFrameDeleted(content::RenderFrameHost* host);
  void OnDidFinishNavigation(content::RenderFrameHost* host);

  // Returns the tracked highest priority matching allowsAllRequests action, if
  // any, for |host|.
  base::Optional<RequestAction> GetAllowlistedFrameActionForTesting(
      content::RenderFrameHost* host) const;

 protected:
  using ExtensionMetadataList =
      ::flatbuffers::Vector<flatbuffers::Offset<flat::UrlRuleMetadata>>;

  // Helper to create a RequestAction of type |BLOCK| or |COLLAPSE|.
  RequestAction CreateBlockOrCollapseRequestAction(
      const RequestParams& params,
      const url_pattern_index::flat::UrlRule& rule) const;

  // Helper to create a RequestAction of type |ALLOW|.
  RequestAction CreateAllowAction(
      const RequestParams& params,
      const url_pattern_index::flat::UrlRule& rule) const;

  // Helper to create a RequestAction of type |ALLOW_ALL_REQUESTS|.
  RequestAction CreateAllowAllRequestsAction(
      const RequestParams& params,
      const url_pattern_index::flat::UrlRule& rule) const;

  // Helper to create a RequestAction of type |REDIRECT| with the request
  // upgraded. Returns base::nullopt if the request is not upgradeable.
  base::Optional<RequestAction> CreateUpgradeAction(
      const RequestParams& params,
      const url_pattern_index::flat::UrlRule& rule) const;

  // Helpers to create a RequestAction of type |REDIRECT| with the appropriate
  // redirect url. Can return base::nullopt if the redirect url is ill-formed or
  // same as the current request url.
  base::Optional<RequestAction> CreateRedirectActionFromMetadata(
      const RequestParams& params,
      const url_pattern_index::flat::UrlRule& rule,
      const ExtensionMetadataList& metadata_list) const;
  base::Optional<RequestAction> CreateRedirectAction(
      const RequestParams& params,
      const url_pattern_index::flat::UrlRule& rule,
      GURL redirect_url) const;

  // Helper to create a RequestAction of type |REMOVE_HEADERS|. |mask|
  // corresponds to bitmask of flat::RemoveHeaderType, and must be non-empty.
  RequestAction GetRemoveHeadersActionForMask(
      const url_pattern_index::flat::UrlRule& rule,
      uint8_t mask) const;

 private:
  // Returns the ruleset's highest priority matching allowAllRequests action or
  // base::nullopt if there is no corresponding matching rule. Only takes into
  // account the request |params| passed in. This doesn't take any account any
  // matching allowAllRequests rules for ancestor frames.
  virtual base::Optional<RequestAction> GetAllowAllRequestsAction(
      const RequestParams& params) const = 0;

  // Returns the ruleset's highest priority matching RequestAction for the
  // onBeforeRequest phase, or base::nullopt if the ruleset has no matching
  // rule. This doesn't take any account any matching allowAllRequests rules for
  // ancestor frames.
  virtual base::Optional<RequestAction> GetBeforeRequestActionIgnoringAncestors(
      const RequestParams& params) const = 0;

  RequestAction CreateRequestAction(
      RequestAction::Type type,
      const url_pattern_index::flat::UrlRule& rule) const;

  // Returns the matching RequestAction from |allowlisted_frames_| or
  // base::nullopt if none is found.
  base::Optional<RequestAction> GetAllowlistedFrameAction(
      content::GlobalFrameRoutingId frame_id) const;

  const ExtensionId extension_id_;
  const api::declarative_net_request::SourceType source_type_;

  // Stores the IDs for the RenderFrameHosts which are allow-listed due to an
  // allowAllRequests action and the corresponding highest priority
  // RequestAction.
  std::map<content::GlobalFrameRoutingId, const RequestAction>
      allowlisted_frames_;

  DISALLOW_COPY_AND_ASSIGN(RulesetMatcherBase);
};

}  // namespace declarative_net_request
}  // namespace extensions

#endif  // EXTENSIONS_BROWSER_API_DECLARATIVE_NET_REQUEST_RULESET_MATCHER_BASE_H_