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content / browser / preloading / prefetch / prefetch_response_reader.h [blame]
// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CONTENT_BROWSER_PRELOADING_PREFETCH_PREFETCH_RESPONSE_READER_H_
#define CONTENT_BROWSER_PRELOADING_PREFETCH_PREFETCH_RESPONSE_READER_H_
#include "base/time/time.h"
#include "content/browser/preloading/prefetch/prefetch_data_pipe_tee.h"
#include "content/browser/preloading/prefetch/prefetch_streaming_url_loader_common_types.h"
#include "content/common/content_export.h"
#include "mojo/public/cpp/bindings/receiver.h"
#include "mojo/public/cpp/bindings/receiver_set.h"
#include "mojo/public/cpp/bindings/remote.h"
#include "mojo/public/cpp/bindings/remote_set.h"
#include "net/http/http_cookie_indices.h"
#include "services/network/public/mojom/url_loader.mojom.h"
#include "services/network/public/mojom/url_response_head.mojom-forward.h"
namespace content {
class PrefetchStreamingURLLoader;
// `PrefetchResponseReader` stores the prefetched data needed for serving, and
// serves URLLoaderClients (`serving_url_loader_clients_`). One
// `PrefetchResponseReader` corresponds to one
// `PrefetchContainer::SinglePrefetch`, i.e. one redirect hop.
//
// A sequences of events are received from `PrefetchStreamingURLLoader` and
// served to each of `serving_url_loader_clients_`.
//
// `PrefetchResponseReader` is kept alive by:
// - `PrefetchContainer::SinglePrefetch::response_reader_`
// as long as `PrefetchContainer` is alive,
// - `PrefetchResponseReader::self_pointer_`
// while it is serving to its `mojom::URLLoaderClient`, or
// - The `PrefetchRequestHandler` returned by `CreateRequestHandler()`
// until it is called.
//
// TODO(crbug.com/40064891): Currently at most one client per
// `PrefetchResponseReader` is allowed due to other servablility conditions.
// Upcoming CLs will enable multiple clients/navigation requests per
// `PrefetchResponseReader` behind a flag.
class CONTENT_EXPORT PrefetchResponseReader final
: public network::mojom::URLLoader,
public base::RefCounted<PrefetchResponseReader> {
public:
// TODO(crbug.com/373553133): Stop using two different constructors once we
// find how we enable `is_reusable_` path.
explicit PrefetchResponseReader(bool is_reusable);
// For
// //content/browser/preloading/prefetch/prefetch_streaming_url_loader_unittest.cc
explicit PrefetchResponseReader();
void SetStreamingURLLoader(
base::WeakPtr<PrefetchStreamingURLLoader> streaming_url_loader);
base::WeakPtr<PrefetchStreamingURLLoader> GetStreamingLoader() const;
// Asynchronously release `self_pointer_` if eligible. Note that `this` might
// be still be kept alive by others even after that.
void MaybeReleaseSoonSelfPointer();
// Adds events from the methods with the same names in
// `PrefetchStreamingURLLoader` to `event_queue_` and existing
// `serving_url_loader_clients_`.
void OnReceiveEarlyHints(network::mojom::EarlyHintsPtr early_hints);
void OnReceiveResponse(std::optional<PrefetchErrorOnResponseReceived> status,
network::mojom::URLResponseHeadPtr head,
mojo::ScopedDataPipeConsumerHandle body);
void HandleRedirect(PrefetchRedirectStatus redirect_status,
const net::RedirectInfo& redirect_info,
network::mojom::URLResponseHeadPtr redirect_head);
void OnTransferSizeUpdated(int32_t transfer_size_diff);
void OnComplete(network::URLLoaderCompletionStatus completion_status);
// Creates a request handler to serve the response of the prefetch.
//
// `CreateRequestHandler()` is responsible for the final check for servability
// and can return a null PrefetchRequestHandler if the final check fails (even
// if `GetServableState()` previously returned `kServable`).
//
// The caller is responsible for:
// - Cookie-related checks and processing.
// For example, checking `HaveDefaultContextCookiesChanged()` is false and
// copying isolated cookies if needed.
// `PrefetchResponseReader::CreateRequestHandler()`,
// `PrefetchResponseReader::Servable()` nor
// `PrefetchContainer::GetServableState()` don't perform cookie-related
// checks.
// - Checking `Servable()`/`GetServableState()`.
// `cacheable_duration` is checked only there.
PrefetchRequestHandler CreateRequestHandler();
bool Servable(base::TimeDelta cacheable_duration) const;
bool IsWaitingForResponse() const;
std::optional<network::URLLoaderCompletionStatus> GetCompletionStatus()
const {
return completion_status_;
}
const network::mojom::URLResponseHead* GetHead() const { return head_.get(); }
// True if this response had Vary: Cookie (or Vary: *), and a Cookie-Indices
// header also applies.
bool VariesOnCookieIndices() const;
// True if the request cookies `cookies` match those originally used when the
// prefetch request was made, to the extent required by Cookie-Indices.
// Do not call this if |VariesOnCookieIndices()| returns false.
bool MatchesCookieIndices(
base::span<const std::pair<std::string, std::string>> cookies) const;
base::WeakPtr<PrefetchResponseReader> GetWeakPtr() {
return weak_ptr_factory_.GetWeakPtr();
}
bool is_reusable() const { return is_reusable_; }
private:
// Identifies a client in `serving_url_loader_clients_`.
using ServingUrlLoaderClientId = mojo::RemoteSetElementId;
friend class base::RefCounted<PrefetchResponseReader>;
~PrefetchResponseReader() override;
void BindAndStart(
mojo::ScopedDataPipeConsumerHandle body,
const network::ResourceRequest& resource_request,
mojo::PendingReceiver<network::mojom::URLLoader> receiver,
mojo::PendingRemote<network::mojom::URLLoaderClient> client);
// Adds an event to the queue.
// The callbacks are called in-order for each of
// `serving_url_loader_clients_`, regardless of whether events are added
// before or after clients are added.
void AddEventToQueue(
base::RepeatingCallback<void(ServingUrlLoaderClientId)> callback);
// Sends all stored events in `event_queue_` to the client.
// Called when a new client (identified by `client_id_`) is added.
void RunEventQueue(ServingUrlLoaderClientId client_id);
// Helper functions to send the appropriate events to a client.
void ForwardCompletionStatus(ServingUrlLoaderClientId client_id);
void ForwardEarlyHints(const network::mojom::EarlyHintsPtr& early_hints,
ServingUrlLoaderClientId client_id);
void ForwardTransferSizeUpdate(int32_t transfer_size_diff,
ServingUrlLoaderClientId client_id);
void ForwardRedirect(const net::RedirectInfo& redirect_info,
const network::mojom::URLResponseHeadPtr&,
ServingUrlLoaderClientId client_id);
void ForwardResponse(ServingUrlLoaderClientId client_id);
// network::mojom::URLLoader
void FollowRedirect(
const std::vector<std::string>& removed_headers,
const net::HttpRequestHeaders& modified_headers,
const net::HttpRequestHeaders& modified_cors_exempt_headers,
const std::optional<GURL>& new_url) override;
void SetPriority(net::RequestPriority priority,
int32_t intra_priority_value) override;
void PauseReadingBodyFromNet() override;
void ResumeReadingBodyFromNet() override;
void OnServingURLLoaderMojoDisconnect();
PrefetchStreamingURLLoaderStatus GetStatusForRecording() const;
// Stores info from the response head that will be needed later, before it is
// stored into `head_` (for non-redirect responses) or `event_queue_` (or
// redirect responses).
void StoreInfoFromResponseHead(const network::mojom::URLResponseHead& head);
// If true, the body is reusable with help of `PrefetchDataPipeTee`.
const bool is_reusable_;
// All URLLoader events are queued up here.
std::vector<base::RepeatingCallback<void(ServingUrlLoaderClientId)>>
event_queue_;
// The status of the event queue.
enum class EventQueueStatus {
kNotRunning,
kRunning,
};
EventQueueStatus event_queue_status_{EventQueueStatus::kNotRunning};
// Valid state transitions (which imply valid event sequences) are:
// - Redirect: `kStarted` -> `kRedirectHandled`
// - Non-redirect: `kStarted` -> `kResponseReceived` -> `kCompleted`
// - Failure: `kStarted` -> `kFailed`
// `kStarted` -> `kFailedRedirect`
// `kStarted` -> `kFailedResponseReceived` -> `kFailed`
// `kStarted` -> `kResponseReceived` -> `kFailed`
// Optional `OnReceiveEarlyHints()` and `OnTransferSizeUpdated()` events can
// be received in any non-final states.
enum class LoadState {
// Initial state, not yet receiving a redirect nor non-redirect response.
kStarted,
// [Final] A redirect response is received (`HandleRedirect()` is called).
// This is a final state because we always switch to a new
// `PrefetchResponseReader` on redirects.
kRedirectHandled,
// [servable] A non-redirect successful response is received
// (`OnReceiveResponse()` is called with `servable` = true).
kResponseReceived,
// A non-redirect failed response is received (`OnReceiveResponse()` is
// called with `servable` = false).
kFailedResponseReceived,
// [Final, servable] Successful completion (`OnComplete(net::OK)` is called
// after `kResponseReceived`.
kCompleted,
// [Final] Failed completion (`OnComplete()` is called, either with
// non-`net::OK`, or after `kFailedResponseReceived`).
kFailed,
// [Final] Failed redirects.
kFailedRedirect
};
LoadState load_state_{LoadState::kStarted};
// Used for UMA recording.
// TODO(crbug.com/40064891): we might want to adapt these flags and UMA
// semantics for multiple client settings, but so far we don't have any
// specific plans.
std::optional<PrefetchErrorOnResponseReceived> failure_reason_;
bool served_before_completion_{false};
bool served_after_completion_{false};
bool should_record_metrics_{true};
// If present, this includes the sorted and unique names of the cookies which
// were specified in the Cookie-Indices header, and a hash of their values as
// obtained from `net::HashCookieIndices`. This is not set unless the Vary
// header also specified Cookie (or *).
//
// As one quirk, we presently still don't vary on cookies if Vary is specified
// and Cookie-Indices isn't, both because that was the prior behavior and
// because doing so requires having the precise string value of the header
// (including whitespace).
struct CookieIndicesInfo {
CookieIndicesInfo();
~CookieIndicesInfo();
std::vector<std::string> cookie_names;
net::CookieIndicesHash expected_hash;
};
std::optional<CookieIndicesInfo> cookie_indices_;
// The prefetched data and metadata. Not set for a redirect response.
network::mojom::URLResponseHeadPtr head_;
// `body_` is set/used only when `!is_reusable_`.
mojo::ScopedDataPipeConsumerHandle body_;
// `body_tee_` is set/used only when `is_reusable_`.
scoped_refptr<PrefetchDataPipeTee> body_tee_;
std::optional<network::URLLoaderCompletionStatus> completion_status_;
// Recorded on `OnComplete` and used to check if the prefetch data is still
// fresh for use.
std::optional<base::TimeTicks> response_complete_time_;
// Only used temporarily to plumb the body `BindAndStart()` to
// `ForwardResponse()`.
mojo::ScopedDataPipeConsumerHandle forward_body_;
// The URL loader clients that will serve the prefetched data.
mojo::ReceiverSet<network::mojom::URLLoader> serving_url_loader_receivers_;
mojo::RemoteSet<network::mojom::URLLoaderClient> serving_url_loader_clients_;
// Set when this manages its own lifetime.
scoped_refptr<PrefetchResponseReader> self_pointer_;
base::WeakPtr<PrefetchStreamingURLLoader> streaming_url_loader_;
base::WeakPtrFactory<PrefetchResponseReader> weak_ptr_factory_{this};
};
} // namespace content
#endif // CONTENT_BROWSER_PRELOADING_PREFETCH_PREFETCH_RESPONSE_READER_H_