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// Copyright 2018 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_RENDERER_HOST_BACK_FORWARD_CACHE_IMPL_H_
#define CONTENT_BROWSER_RENDERER_HOST_BACK_FORWARD_CACHE_IMPL_H_
#include <list>
#include <memory>
#include <set>
#include <unordered_set>
#include "base/feature_list.h"
#include "base/gtest_prod_util.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/raw_ref.h"
#include "base/memory/weak_ptr.h"
#include "base/task/single_thread_task_runner.h"
#include "base/time/time.h"
#include "base/types/expected.h"
#include "content/browser/renderer_host/back_forward_cache_can_store_document_result.h"
#include "content/browser/renderer_host/back_forward_cache_metrics.h"
#include "content/browser/renderer_host/page_impl.h"
#include "content/browser/renderer_host/render_process_host_internal_observer.h"
#include "content/browser/renderer_host/stored_page.h"
#include "content/common/content_export.h"
#include "content/public/browser/back_forward_cache.h"
#include "content/public/browser/global_routing_id.h"
#include "content/public/browser/render_process_host.h"
#include "content/public/browser/render_process_host_observer.h"
#include "content/public/browser/site_instance.h"
#include "content/public/browser/storage_partition.h"
#include "content/public/common/content_features.h"
#include "net/cookies/canonical_cookie.h"
#include "services/network/public/mojom/cookie_manager.mojom.h"
#include "third_party/blink/public/mojom/back_forward_cache_not_restored_reasons.mojom.h"
#include "third_party/blink/public/mojom/frame/back_forward_cache_controller.mojom.h"
#include "third_party/blink/public/mojom/page/page.mojom.h"
#include "third_party/perfetto/include/perfetto/tracing/traced_value_forward.h"
#include "url/gurl.h"
namespace content {
class RenderFrameHostImpl;
class SiteInstance;
// This feature is used to limit the scope of back-forward cache experiment
// without enabling it. To control the URLs list by using this feature by
// generating the metrics only for "allowed_websites" param. Mainly, to ensure
// that metrics from the control and experiment groups are consistent.
BASE_FEATURE(kRecordBackForwardCacheMetricsWithoutEnabling,
"RecordBackForwardCacheMetricsWithoutEnabling",
base::FEATURE_DISABLED_BY_DEFAULT);
// Removes the time limit for cached content. This is used on bots to identify
// accidentally passing tests.
BASE_FEATURE(kBackForwardCacheNoTimeEviction,
"BackForwardCacheNoTimeEviction",
base::FEATURE_DISABLED_BY_DEFAULT);
// Feature to allow exposing cross-origin subframes' NotRestoredReasons.
BASE_FEATURE(kAllowCrossOriginNotRestoredReasons,
"AllowCrossOriginNotRestoredReasons",
base::FEATURE_DISABLED_BY_DEFAULT);
CONTENT_EXPORT BASE_DECLARE_FEATURE(kBackForwardCacheSize);
CONTENT_EXPORT extern const base::FeatureParam<int>
kBackForwardCacheSizeCacheSize;
CONTENT_EXPORT extern const base::FeatureParam<int>
kBackForwardCacheSizeForegroundCacheSize;
// When a prioritized BFCache entry needs to be evicted, it will be kept
// in the cache instead. Only the latest prioritized entry outside the limit
// will be handled in this way.
BASE_FEATURE(kBackForwardCachePrioritizedEntry,
"BackForwardCachePrioritizedEntry",
base::FEATURE_DISABLED_BY_DEFAULT);
// Controls the interaction between back/forward cache and
// unload. When enabled, pages with unload handlers may enter the
// cache.
BASE_FEATURE(kBackForwardCacheUnloadAllowed,
"BackForwardCacheUnloadAllowed",
#if BUILDFLAG(IS_ANDROID)
base::FEATURE_ENABLED_BY_DEFAULT
#else
base::FEATURE_DISABLED_BY_DEFAULT
#endif
);
// Combines a flattened list and a tree of the reasons why each document cannot
// enter the back/forward cache (might be empty if it can). The tree saves the
// reasons for each document in the tree (including those without the reasons)
// in a tree format, with each node corresponding to one document. The flattened
// list is the combination of all reasons for all documents in the tree.
// CONTENT_EXPORT is for exporting only for testing.
struct CONTENT_EXPORT BackForwardCacheCanStoreDocumentResultWithTree {
BackForwardCacheCanStoreDocumentResultWithTree(
BackForwardCacheCanStoreDocumentResult& flattened_reasons,
std::unique_ptr<BackForwardCacheCanStoreTreeResult> tree_reasons);
BackForwardCacheCanStoreDocumentResultWithTree(
BackForwardCacheCanStoreDocumentResultWithTree&& other);
~BackForwardCacheCanStoreDocumentResultWithTree();
BackForwardCacheCanStoreDocumentResult flattened_reasons;
std::unique_ptr<BackForwardCacheCanStoreTreeResult> tree_reasons;
// The conditions for storing and restoring the pages are different in that
// pages with cache-control:no-store can enter back/forward cache depending on
// the experiment flag, but can never be restored.
bool CanStore() const { return flattened_reasons.CanStore(); }
bool CanRestore() const { return flattened_reasons.CanRestore(); }
};
// BackForwardCache:
//
// After the user navigates away from a document, the old one goes into the
// frozen state and is kept in this object. They can potentially be reused
// after an history navigation. Reusing a document means swapping it back with
// the current_frame_host.
//
//
// BackForwardCache Size & Pruning Logic:
//
// 1. `EnforceCacheSizeLimit()` is called to prune the cache size down on
// storing a new cache entry, or when the renderer process's
// `GetPriority()` state changes.
// A. [Android-only] The number of entries where `HasForegroundedProcess()`
// is true is pruned to `GetForegroundedEntriesCacheSize()`.
// B. Prunes to `GetCacheSize()` entries no matter what kinds of tabs
// BackForwardCache is in.
// C. When a `RenderFrameHost` enters BackForwardCache, it schedules a task
// in `RenderFrameHostImpl::StartBackForwardCacheEvictionTimer()` to
// evicts the outermost frame after
// `kDefaultTimeToLiveInBackForwardCacheInSeconds` seconds.
// 2. In `performance_manager::policies::BFCachePolicy`:
// A. [Desktop-only] On moderate memory pressure, the number of entries in a
// visible tab's cache is pruned to
// `ForegroundCacheSizeOnModeratePressure()`. The number in a non-visible
// tab is pruned to `BackgroundCacheSizeOnModeratePressure()`.
// B. [Desktop-only] On critical memory pressure, the cache is cleared.
class CONTENT_EXPORT BackForwardCacheImpl
: public BackForwardCache,
public RenderProcessHostInternalObserver,
public StoredPage::Delegate {
friend class BackForwardCacheCanStoreTreeResult;
friend class BackForwardCacheMetrics;
public:
enum MessageHandlingPolicyWhenCached {
kMessagePolicyNone,
kMessagePolicyLog,
kMessagePolicyDump,
};
static MessageHandlingPolicyWhenCached
GetChannelAssociatedMessageHandlingPolicy();
// BackForwardCache entry, consisting of the page and associated metadata.
class Entry {
public:
explicit Entry(std::unique_ptr<StoredPage> stored_page);
~Entry();
void WriteIntoTrace(perfetto::TracedValue context);
// Indicates whether or not all the |render_view_hosts| in this entry have
// received the acknowledgement from renderer that it finished running
// handlers.
bool AllRenderViewHostsReceivedAckFromRenderer();
std::unique_ptr<StoredPage> TakeStoredPage() {
return std::move(stored_page_);
}
void SetPageRestoreParams(
blink::mojom::PageRestoreParamsPtr page_restore_params) {
stored_page_->SetPageRestoreParams(std::move(page_restore_params));
}
void SetStoredPageDelegate(StoredPage::Delegate* delegate) {
stored_page_->SetDelegate(delegate);
}
void SetViewTransitionState(
std::optional<blink::ViewTransitionState> view_transition_state) {
stored_page_->SetViewTransitionState(std::move(view_transition_state));
}
// The main document being stored.
RenderFrameHostImpl* render_frame_host() {
return stored_page_->render_frame_host();
}
const StoredPage::RenderViewHostImplSafeRefSet& render_view_hosts() {
return stored_page_->render_view_hosts();
}
const StoredPage::RenderFrameProxyHostMap& proxy_hosts() const {
return stored_page_->proxy_hosts();
}
size_t proxy_hosts_size() { return stored_page_->proxy_hosts_size(); }
private:
friend class BackForwardCacheImpl;
std::unique_ptr<StoredPage> stored_page_;
};
explicit BackForwardCacheImpl(BrowserContext* browser_context);
BackForwardCacheImpl(const BackForwardCacheImpl&) = delete;
BackForwardCacheImpl& operator=(const BackForwardCacheImpl&) = delete;
~BackForwardCacheImpl() override;
// Returns where back/forward cache is allowed for pages with unload handlers.
static bool IsUnloadAllowed();
// Log an unexpected message from the renderer. Doing it here so that it is
// grouped with other back/forward cache vlogging and e.g. will show up in
// test logs. `message_name` varies in each build however when a test failure
// occurs, it should be possible to recreate the build and find which message
// corresponds to this the value.
static void VlogUnexpectedRendererToBrowserMessage(
const char* interface_name_,
uint32_t message_name,
RenderFrameHostImpl* rfh);
// Returns the reasons (if any) why this document and its children cannot
// enter the back/forward cache. Depends on the |render_frame_host| and its
// children's state. Should only be called after we've navigated away from
// |render_frame_host|, which means nothing about the page can change (usage
// of blocklisted features, pending navigations, load state, etc.) anymore.
// Note that criteria for storing and restoring can be different, i.e.
// |CanStore()| and |CanRestore()| might give different results.
// Note that the returned result will not include non-sticky features if the
// browser has not received an IPC ACK from the renderer. See also the
// comments for |RequestedFeatures|. If you always want to include non-sticky
// features, use GetCompleteBackForwardCacheEligibilityForReporting() instead.
BackForwardCacheCanStoreDocumentResultWithTree
GetCurrentBackForwardCacheEligibility(RenderFrameHostImpl* render_frame_host);
// Whether a RenderFrameHost could be stored into the BackForwardCache at some
// point in the future. Different than GetCurrentBackForwardCacheEligibility()
// above and GetCompleteBackForwardCacheEligibilityForReporting() below, we
// won't check for properties of |render_frame_host| that might change in the
// future such as usage of certain APIs (non-sticky features), loading state,
// existence of pending navigation requests, etc. This should be treated as a
// "best guess" on whether a page still has a chance to be stored in the
// back-forward cache later on, and should not be used as a final check before
// storing a page to the back-forward cache (for that, use
// GetCurrentBackForwardCacheEligibility() instead).
BackForwardCacheCanStoreDocumentResultWithTree
GetFutureBackForwardCacheEligibilityPotential(
RenderFrameHostImpl* render_frame_host);
// This will return all the reasons present at the point of calling that could
// block back/forward cache, including both sticky and non-sticky features,
// regardless of the IPC ack status (unlike
// GetCurrentBackForwardCacheEligibility()). Note that non-sticky features
// might get cleaned in pagehide handlers and might not block back/forward
// cache, and this result will include them anyway.
BackForwardCacheCanStoreDocumentResultWithTree
GetCompleteBackForwardCacheEligibilityForReporting(
RenderFrameHostImpl* render_frame_host);
// Moves the specified BackForwardCache entry into the BackForwardCache. It
// can be reused in a future history navigation by using RestoreEntry(). When
// the BackForwardCache is full, the least recently used document is evicted.
// Precondition: CanStoreDocument(*(entry->render_frame_host)).
void StoreEntry(std::unique_ptr<Entry> entry);
// Ensures that the cache is within its size limits. This should be called
// whenever events occur that could put the cache outside its limits. What
// those events are depends on the cache limit policy.
void EnforceCacheSizeLimit();
enum GetEntryFailureCase {
// No matched BFCache entry is found.
kEntryNotFound,
// BFCache entry is found, but it was evicted before the `GetOrEvictEntry()`
// call.
kEntryEvictedBefore,
// BFCache entry is found and not evicted, but it's no longer eligible for
// BFCache, and gets evicted in the `GetOrEvictEntry()` call.
kEntryIneligibleAndEvicted,
};
// Returns a pointer to a cached BackForwardCache entry matching
// `navigation_entry_id`.
// Returns nullptr if no matching entry is found or if the entry is evicted.
// If the returned entry is null, this method will also return a
// `BackForwardCacheImpl::GetEntryResult`, which contains information about
// whether it's because a matching entry was found or the entry was evicted.
// Note: The returned pointer should be used temporarily only within the
// execution of a single task on the event loop. Beyond that, there is no
// guarantee the pointer will be valid, because the document may be
// removed/evicted from the cache.
// WARNING: Calling this method may result in the eviction of the BFCache
// entry if it is no longer eligible for the BFCache but has not been evicted
// yet. If the eviction is triggered while there is an ongoing BFCache
// restore, the caller must discard the NavigationRequest that is about to
// commit the restore, otherwise the NavigationRequest may try to access the
// RenderFrameHost after it has been deleted.
base::expected<BackForwardCacheImpl::Entry*,
BackForwardCacheImpl::GetEntryFailureCase>
GetOrEvictEntry(int navigation_entry_id);
// During a history navigation, moves an entry out of the BackForwardCache
// knowing its |navigation_entry_id|. |page_restore_params| includes
// information that is needed by the entry's page after getting restored,
// which includes the latest history information (offset, length) and the
// timestamp corresponding to the start of the back-forward cached navigation,
// which would be communicated to the page to allow it to record the latency
// of this navigation.
std::unique_ptr<Entry> RestoreEntry(
int navigation_entry_id,
blink::mojom::PageRestoreParamsPtr page_restore_params);
// Evict all cached pages in the same BrowsingInstance as
// |site_instance|.
void EvictFramesInRelatedSiteInstances(SiteInstance* site_instance);
// Immediately deletes all frames in the cache. This should only be called
// when WebContents is being destroyed.
void Shutdown();
// Posts a task to destroy all frames in the BackForwardCache that have been
// marked as evicted.
void PostTaskToDestroyEvictedFrames();
// This enum indicates if the method is called from a "Cache-Control:
// no-store" context, i.e. the page's same-origin main document has
// "Cache-Control: no-store" header.
enum CacheControlNoStoreContext {
kInCCNSContext,
kNotInCCNSContext,
};
// Storing frames in back-forward cache is not supported indefinitely
// due to potential privacy issues and memory leaks. Instead we are evicting
// the frame from the cache after the time to live, which can be controlled
// via experiment.
// The return value may vary depending on if the main frame of the cached page
// has "Cache-Control: no-store" header.
static base::TimeDelta GetTimeToLiveInBackForwardCache(
CacheControlNoStoreContext ccns_context);
// Gets the maximum number of entries the BackForwardCache can hold per tab.
static size_t GetCacheSize();
// The back-forward cache is experimented on a limited set of URLs. This
// method returns true if the |url| matches one of those. URL not matching
// this won't enter the back-forward cache. This can still return true even
// when BackForwardCache is disabled for metrics purposes. It checks
// |IsHostPathAllowed| then |IsHostPathAllowed|
bool IsAllowed(const GURL& current_url);
// Returns true if the host and path are allowed according to the
// "allowed_websites" and "blocked_webites" parameters of
// |feature::kBackForwardCache|. An empty "allowed_websites" implies that all
// websites are allowed.
bool IsHostPathAllowed(const GURL& current_url);
// Returns true if query does not contain any of the parameters in
// "blocked_cgi_params" parameter of |feature::kBackForwardCache|. The
// comparison is done by splitting the query string on "&" and looking for
// exact matches in the list (parameter name and value). It does not consider
// URL escaping.
bool IsQueryAllowed(const GURL& current_url);
// Called just before commit for a navigation that's served out of the back
// forward cache. This method will disable eviction in renderers and invoke
// |done_callback| when they are ready for the navigation to be committed.
void WillCommitNavigationToCachedEntry(Entry& bfcache_entry,
base::OnceClosure done_callback);
// Returns the task runner that should be used by the eviction timer.
scoped_refptr<base::SingleThreadTaskRunner> GetTaskRunner() {
return task_runner_for_testing_
? task_runner_for_testing_
: base::SingleThreadTaskRunner::GetCurrentDefault();
}
// Inject task runner for precise timing control in browser tests.
void SetTaskRunnerForTesting(
scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
task_runner_for_testing_ = task_runner;
}
const std::list<std::unique_ptr<Entry>>& GetEntries();
std::list<Entry*> GetEntriesForRenderViewHostImpl(
const RenderViewHostImpl* rvhi) const;
// BackForwardCache overrides:
void Flush() override;
void Flush(NotRestoredReason reason) override;
void Prune(size_t limit, NotRestoredReason reason) override;
void DisableForTesting(DisableForTestingReason reason) override;
// Evict all entries from the BackForwardCache that match the removal filter.
void Flush(
const StoragePartition::StorageKeyMatcherFunction& storage_key_filter);
// Evict all entries from the BackForwardCache that were loaded with
// "Cache-Control: no-store" header and match the removal filter.
void FlushCacheControlNoStoreEntries(
const StoragePartition::StorageKeyMatcherFunction& storage_key_filter);
// RenderProcessHostInternalObserver methods
void RenderProcessPriorityChanged(RenderProcessHostImpl* host) override;
// Returns true if we are managing the cache size using foreground and
// background limits (if finch parameter "foreground_cache_size" > 0).
static bool UsingForegroundBackgroundCacheSizeLimit();
// Returns true if one of the BFCache entries has a matching
// RFH/RFPH/RVH with the same SIG ID/RVH ID.
// TODO(crbug.com/354382462): Remove these once the bug is fixed.
bool IsRenderFrameHostWithSIGInBackForwardCacheForDebugging(
SiteInstanceGroupId site_instance_group_id);
bool IsRenderFrameProxyHostWithSIGInBackForwardCacheForDebugging(
SiteInstanceGroupId site_instance_group_id);
bool IsRenderViewHostWithMapIdInBackForwardCacheForDebugging(
const RenderViewHostImpl& rvh);
bool IsRelatedSiteInstanceInBackForwardCacheForDebugging(
SiteInstance& site_instance);
// StoredPage::Delegate overrides:
void RenderViewHostNoLongerStored(RenderViewHostImpl* rvh) override;
// Construct a tree of NotRestoredReasons for |rfh| without checking the
// eligibility of all the documents in the frame tree. This should be only
// used for evicting the back/forward cache entry where we know why the entry
// is not eligible and which document is causing it.
// This preserves the frame tree structure after eviction, because the actual
// page and frame tree is not kept around after eviction.
// |rfh| will be marked as having |eviction_reason| as not restored reasons.
static BackForwardCacheCanStoreDocumentResultWithTree
CreateEvictionBackForwardCacheCanStoreTreeResult(
RenderFrameHostImpl& rfh,
BackForwardCacheCanStoreDocumentResult& eviction_reason);
bool should_allow_storing_pages_with_cache_control_no_store() {
return should_allow_storing_pages_with_cache_control_no_store_;
}
// Returns true if there is a BFCached entry that sufficiently matches the
// navigation that just committed in `committing_rfh` with initiator origin
// `initiator_origin`, such that the entry could have been used (the URL,
// origin, initiator origin, and security properties are the same, and if
// `require_no_subframes` is used, has no subframes). This is
// called in response to new non-reload/session-restore cross-document
// navigation commits.
bool HasPotentiallyMatchingEntry(
const RenderFrameHostImpl& committing_rfh,
const std::optional<url::Origin>& initiator_origin,
bool require_no_subframes) const;
private:
// Destroys all evicted frames in the BackForwardCache.
void DestroyEvictedFrames();
// Populates the reasons that are only relevant for main documents such as
// browser settings, the main document's URL & HTTP status, etc.
void PopulateReasonsForMainDocument(
BackForwardCacheCanStoreDocumentResult& result,
RenderFrameHostImpl* render_frame_host);
// This enum indicates what features to include when recording
// NotRestoredReasons.
enum RequestedFeatures {
// Report only sticky reasons.
kOnlySticky,
// If the entry has received an IPC ack from the renderer, report all the
// reasons. Otherwise only include sticky features, because non-sticky
// features might be removed by the renderer when the browser signals it is
// about to put the page into BFCache.
kAllIfAcked,
// Regardless of the ack status, report all the reasons.
kAll,
};
// Populates the reasons why this |rfh| and its subframes cannot enter the
// back/forward cache in a flat list through |flattened_result| and as a tree
// through its return value.
// |requested_features| controls whether we include non-sticky reasons in the
// result.
BackForwardCacheCanStoreDocumentResultWithTree PopulateReasonsForPage(
RenderFrameHostImpl* rfh,
BackForwardCacheCanStoreDocumentResult& flattened_result,
RequestedFeatures requested_features);
// Updates the result to include CacheControlNoStore reasons if the flag is
// on.
void UpdateCanStoreToIncludeCacheControlNoStore(
BackForwardCacheCanStoreDocumentResult& result,
RenderFrameHostImpl* render_frame_host);
// Return the matching entry which has |page|.
BackForwardCacheImpl::Entry* FindMatchingEntry(PageImpl& page);
void RenderViewHostNoLongerStoredInternal(RenderViewHostImpl* rvh);
// If non-zero, the cache may contain at most this many entries with involving
// foregrounded processes and the remaining space can only be used by entries
// with no foregrounded processes. We can be less strict on memory usage of
// background processes because Android will kill the process if memory
// becomes scarce.
static size_t GetForegroundedEntriesCacheSize();
// Enforces a limit on the number of entries. Which entries are counted
// towards the limit depends on the values of `reason`.
// If it's `kForegroundCacheLimit`, it only considers entries that are
// associated with a foregrounded process. Otherwise all entries are
// considered.
// If it's
// `kCacheLimitPrunedOnModerateMemoryPressure` or
// `kCacheLimitPrunedOnCriticalMemoryPressure`, it means the enforcement is
// triggered by the `Prune()` method.
size_t EnforceCacheSizeLimitInternal(
size_t limit,
BackForwardCacheMetrics::NotRestoredReason reason);
// Updates |process_to_entry_map_| with processes from |entry|. These must
// be called after adding or removing an entry in |entries_|.
void AddProcessesForEntry(Entry& entry);
void RemoveProcessesForEntry(Entry& entry);
static BlockListedFeatures GetAllowedFeatures(
RequestedFeatures requested_features,
CacheControlNoStoreContext ccns_context);
static BlockListedFeatures GetDisallowedFeatures(
RequestedFeatures requested_features,
CacheControlNoStoreContext ccns_context);
// Contains the set of stored Entries.
// Invariant:
// - Ordered from the most recently used to the last recently used.
// - Once the list is full, the least recently used document is evicted.
std::list<std::unique_ptr<Entry>> entries_;
// The iterator pointing at the entry that was supposed to be evicted, but
// since it's a prioritized entry, it will be specially kept in the entry
// list.
std::list<std::unique_ptr<Entry>>::iterator prioritized_entry_ =
entries_.end();
// Keeps track of the observed RenderProcessHosts. This is populated
// from and kept in sync with |entries_|. The RenderProcessHosts are collected
// from each Entry's RenderViewHosts. Every RenderProcessHost in here is
// observed by |this|. Every RenderProcessHost in this is referenced by a
// RenderViewHost in the Entry and so will be valid.
std::multiset<RenderProcessHost*> observed_processes_;
// Whether the BackForwardCache has been enabled for pages loaded with
// "Cache-Control: no-store" header.
bool should_allow_storing_pages_with_cache_control_no_store_;
// Only used in tests. Whether the BackforwardCache has been disabled for
// testing.
bool is_disabled_for_testing_ = false;
// Only used for tests. This task runner is used for precise injection in
// browser tests and for timing control.
scoped_refptr<base::SingleThreadTaskRunner> task_runner_for_testing_;
// To enter the back-forward cache, the main document URL's must match one of
// the field trial parameter "allowed_websites". This is represented here by a
// set of host and path prefix. When |allowed_urls_| is empty, it means there
// are no restrictions on URLs.
const base::flat_map<std::string, // URL's host,
std::vector<std::string> // URL's path prefix
>
allowed_urls_;
// This is an emergency kill switch per url to stop BFCache. The data will be
// provided via the field trial parameter "blocked_websites".
// "blocked_websites" have priority over "allowed_websites". This is
// represented here by a set of host and path prefix.
const base::flat_map<std::string, // URL's host,
std::vector<std::string> // URL's path prefix
>
blocked_urls_;
// Data provided from the "blocked_cgi_params" feature param. If any of these
// occur in the query of the URL then the page is not eligible for caching.
// See |IsQueryAllowed|.
const base::flat_set<std::string> blocked_cgi_params_;
// Helper class to iterate through the frame tree in the page and populate the
// NotRestoredReasons.
class NotRestoredReasonBuilder {
public:
// Construct a tree of NotRestoredReasons by checking the eligibility of
// each frame in the frame tree rooted at |root_rfh|.
// |root_rfh| represents the root document of the page. |include_non_sticky|
// controls whether or not we should record non-sticky reasons in the tree.
NotRestoredReasonBuilder(RenderFrameHostImpl* root_rfh,
RequestedFeatures requested_features);
// Struct for containing the RenderFrameHostImpl that is going to be
// evicted if applicable. |reasons| represent why |rfh_to_be_evicted| will
// be evicted.
struct EvictionInfo {
EvictionInfo(RenderFrameHostImpl& rfh,
BackForwardCacheCanStoreDocumentResult* reasons)
: rfh_to_be_evicted(&rfh), reasons(reasons) {}
const raw_ptr<RenderFrameHostImpl> rfh_to_be_evicted;
raw_ptr<const BackForwardCacheCanStoreDocumentResult> reasons;
};
NotRestoredReasonBuilder(RenderFrameHostImpl* root_rfh,
RequestedFeatures requested_features,
std::optional<EvictionInfo> eviction_info);
~NotRestoredReasonBuilder();
// Access the populated result.
BackForwardCacheCanStoreDocumentResult& GetFlattenedResult() {
// TODO(yuzus): Check that |flattened_result_| and the tree result match.
return flattened_result_;
}
std::unique_ptr<BackForwardCacheCanStoreTreeResult> GetTreeResult() {
return std::move(tree_result_);
}
// Populates `result` with the blocking reasons for this document. If
// "include_non_sticky" is true, it includes non-sticky reasons.
void PopulateReasonsForDocument(
BackForwardCacheCanStoreDocumentResult& result,
RenderFrameHostImpl* rfh,
RequestedFeatures requested_features);
// Populates the sticky reasons for `rfh` without recursing into subframes.
// Sticky features can't be unregistered and remain active for the rest of
// the lifetime of the page.
void PopulateStickyReasonsForDocument(
BackForwardCacheCanStoreDocumentResult& result,
RenderFrameHostImpl* rfh);
// Populates the non-sticky reasons for `rfh` without recursing into
// subframes. Non-sticky reasons mean the reasons that may be resolved later
// such as when the page releases blocking resources in pagehide.
void PopulateNonStickyReasonsForDocument(
BackForwardCacheCanStoreDocumentResult& result,
RenderFrameHostImpl* rfh,
RequestedFeatures requested_features);
private:
// Populate NotRestoredReasons for the `rfh` by
// iterating the frame tree and populating NotRestoredReasons in
// |flattened_result_|.
std::unique_ptr<BackForwardCacheCanStoreTreeResult> PopulateReasons(
RenderFrameHostImpl* rfh);
// Root document of the tree.
const raw_ptr<RenderFrameHostImpl> root_rfh_;
// BackForwardCacheImpl instance to access eligibility check functions.
const raw_ref<BackForwardCacheImpl> bfcache_;
// Flattened list of NotRestoredReasons for the tree. This is empty at the
// start and has to be merged using |GetFlattenedResult()|.
BackForwardCacheCanStoreDocumentResult flattened_result_;
// Tree result of NotRestoredReasons. This is populated in the constructor.
std::unique_ptr<BackForwardCacheCanStoreTreeResult> tree_result_;
// See |RequestedFeatures|.
const RequestedFeatures requested_features_;
// Contains the information of the RenderFrameHost that causes eviction, if
// applicable. If set, the result returned by the builder will only contain
// the NotRestoredReason for the RenderFrameHost that causes eviction
// (instead of the reasons for the whole tree).
std::optional<EvictionInfo> eviction_info_;
};
base::WeakPtrFactory<BackForwardCacheImpl> weak_factory_;
// For testing:
FRIEND_TEST_ALL_PREFIXES(BackForwardCacheMetricsTest, AllFeaturesCovered);
FRIEND_TEST_ALL_PREFIXES(BackForwardCacheActiveSizeTest, ActiveCacheSize);
FRIEND_TEST_ALL_PREFIXES(BackForwardCacheOverwriteSizeTest,
OverwrittenCacheSize);
FRIEND_TEST_ALL_PREFIXES(BackForwardCacheDefaultSizeTest, DefaultCacheSize);
};
// Allow external code to be notified when back-forward cache is disabled for a
// RenderFrameHost. This should be used only by the testing infrastructure which
// want to know the exact reason why the cache was disabled. There can be only
// one observer.
class CONTENT_EXPORT BackForwardCacheTestDelegate {
public:
BackForwardCacheTestDelegate();
virtual ~BackForwardCacheTestDelegate();
virtual void OnDisabledForFrameWithReason(
GlobalRenderFrameHostId id,
BackForwardCache::DisabledReason reason) = 0;
};
// Represents the reasons that a subtree cannot enter BFCache as a tree with a
// node for every document in the subtree, in frame tree order. It also includes
// documents that have no blocking reason.
class CONTENT_EXPORT BackForwardCacheCanStoreTreeResult {
public:
friend class BackForwardCacheImpl;
using ChildrenVector =
std::vector<std::unique_ptr<BackForwardCacheCanStoreTreeResult>>;
BackForwardCacheCanStoreTreeResult() = delete;
BackForwardCacheCanStoreTreeResult(BackForwardCacheCanStoreTreeResult&) =
delete;
BackForwardCacheCanStoreTreeResult& operator=(
BackForwardCacheCanStoreTreeResult&&) = delete;
~BackForwardCacheCanStoreTreeResult();
// Adds reasons of this subtree's root document to the tree result from
// |BackForwardCacheCanStoreDocumentResult|.
void AddReasonsToSubtreeRootFrom(
const BackForwardCacheCanStoreDocumentResult& result);
// The reasons for this subtree's root document.
const BackForwardCacheCanStoreDocumentResult& GetDocumentResult() const {
return document_result_;
}
// The blocking details map for this subtree's root document.
const BackForwardCacheCanStoreDocumentResult::BlockingDetailsMap&
GetBlockingDetailsMap() const {
return document_result_.blocking_details_map();
}
// Populate NotRestoredReasons mojom struct based on the existing tree of
// reason to report to the renderer.
// This should be called only when the root document is outermost main
// document.
// We have access to attributes of cross-origin iframes that are children of
// same-origin iframes. This method's purpose is to ensure that we only return
// the information that should be exposed based on origin. (i.e. we only
// include information iframes that are direct children of same-origin
// frames).
blink::mojom::BackForwardCacheNotRestoredReasonsPtr
GetWebExposedNotRestoredReasons();
// Flatten the tree and return a flattened list of not restored reasons that
// includes all the reasons in the tree.
const BackForwardCacheCanStoreDocumentResult FlattenTree();
// The children nodes. We can access the children nodes of this
// node/document from this vector.
const ChildrenVector& GetChildren() const { return children_; }
// Whether this subtree's root document's origin is the same origin with the
// origin of the page's root document origin. Returns false if this document
// is cross-origin.
bool IsSameOrigin() const { return is_same_origin_; }
// The URL of the document corresponding to this subtree's root document.
const GURL& GetUrl() const { return url_; }
// Creates and returns an empty tree.
static std::unique_ptr<BackForwardCacheCanStoreTreeResult> CreateEmptyTree(
RenderFrameHostImpl* rfh);
static std::unique_ptr<BackForwardCacheCanStoreTreeResult>
CreateEmptyTreeForNavigation(NavigationRequest* navigation);
private:
friend class BackForwardCacheImplTest;
FRIEND_TEST_ALL_PREFIXES(BackForwardCacheImplTest,
CrossOriginReachableFrameCount);
FRIEND_TEST_ALL_PREFIXES(BackForwardCacheImplTest, CrossOriginAllMasked);
FRIEND_TEST_ALL_PREFIXES(BackForwardCacheImplTestExposeCrossOrigin,
FirstCrossOriginReachable);
FRIEND_TEST_ALL_PREFIXES(BackForwardCacheImplTestExposeCrossOrigin,
SecondCrossOriginReachable);
// This constructor is for creating a tree for |rfh| as the subtree's root
// document's frame.
BackForwardCacheCanStoreTreeResult(
RenderFrameHostImpl* rfh,
const url::Origin& main_document_origin,
const GURL& url,
BackForwardCacheCanStoreDocumentResult& result_for_this_document);
// Creates an empty placeholder tree with the empty result.
BackForwardCacheCanStoreTreeResult(bool is_same_origin, const GURL& url);
// Helper function for |GetWebExposedNotRestoredReasons()|. |index| is the
// random index of the cross-origin iframe that we decided to report
// from all the reachable cross-origin iframes. We decrement this count
// every time we call this function, and report only when |index| is 0 so
// that reporting happens only for randomly picked one of such iframes.
// TODO(crbug.com/41491384): Add "masked" when UA internal reasons such as
// memory pressure and browsing instance not swapped are blocking as well.
blink::mojom::BackForwardCacheNotRestoredReasonsPtr
GetWebExposedNotRestoredReasonsInternal(int& index);
// Returns if any cross-origin iframe in the tree is blocking and is not
// a randomly selected iframe (i.e. does not have "masked" as its reason).
// If this is true, we need to add "masked" to main frame's reasons.
// |index| is the random index of the cross-origin iframe that we decided to
// report from all the reachable cross-origin iframes.
bool HasUnexposedCrossOriginBlockingIframe(int& index);
// Count the number of cross-origin frames that are direct children of
// same-origin frames, including the main frame, in the tree.
uint32_t GetCrossOriginReachableFrameCount();
void FlattenTreeHelper(
BackForwardCacheCanStoreDocumentResult* document_result);
void AppendChild(std::unique_ptr<BackForwardCacheCanStoreTreeResult> child);
// See |GetDocumentResult|
BackForwardCacheCanStoreDocumentResult document_result_;
// See |GetChildren|
ChildrenVector children_;
// See |IsSameOrigin|
const bool is_same_origin_;
// Whether or not the root document of this tree is the outermoust main
// frame's document.
const bool is_root_outermost_main_frame_;
// The id, name and src attribute of the frame owner of this subtree's root
// document.
const std::optional<std::string> id_;
const std::optional<std::string> name_;
const std::optional<std::string> src_;
// See |GetUrl|
const GURL url_;
};
} // namespace content
#endif // CONTENT_BROWSER_RENDERER_HOST_BACK_FORWARD_CACHE_IMPL_H_
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