// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef EXTENSIONS_BROWSER_PROCESS_MANAGER_H_
#define EXTENSIONS_BROWSER_PROCESS_MANAGER_H_

#include <stdint.h>

#include <map>
#include <set>
#include <string>
#include <utility>
#include <vector>

#include "base/functional/callback.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/scoped_refptr.h"
#include "base/memory/weak_ptr.h"
#include "base/observer_list.h"
#include "base/scoped_multi_source_observation.h"
#include "base/uuid.h"
#include "components/keyed_service/core/keyed_service.h"
#include "content/public/browser/devtools_agent_host_observer.h"
#include "content/public/browser/render_process_host_observer.h"
#include "content/public/browser/service_worker_external_request_result.h"
#include "content/public/browser/service_worker_external_request_timeout_type.h"
#include "content/public/common/child_process_id.h"
#include "extensions/browser/activity.h"
#include "extensions/browser/extension_host_observer.h"
#include "extensions/browser/extension_registry_observer.h"
#include "extensions/browser/service_worker/worker_id.h"
#include "extensions/browser/service_worker/worker_id_set.h"
#include "extensions/common/extension_id.h"

class GURL;

namespace content {
class BrowserContext;
class DevToolsAgentHost;
class RenderFrameHost;
class WebContents;
}  // namespace content

namespace extensions {

class Extension;
class ExtensionHost;
class ExtensionRegistry;
class ProcessManagerObserver;

// Manages dynamic state of running Chromium extensions. There is one instance
// of this class per Profile. OTR Profiles have a separate instance that keeps
// track of split-mode extensions only.
class ProcessManager : public KeyedService,
                       public ExtensionRegistryObserver,
                       public content::DevToolsAgentHostObserver,
                       public content::RenderProcessHostObserver,
                       public ExtensionHostObserver {
 public:
  using ExtensionHostSet =
      std::set<raw_ptr<extensions::ExtensionHost, SetExperimental>>;

  // A struct representing an active service worker keepalive.
  struct ServiceWorkerKeepaliveData {
    // The worker ID associated with the keepalive.
    WorkerId worker_id;
    // The type of activity for the keepalive.
    Activity::Type activity_type;
    // Any "additional data" for the keepalive; for instance, this could be
    // the API function or event name.
    std::string extra_data;
    // The timeout behavior for the given request.
    content::ServiceWorkerExternalRequestTimeoutType timeout_type;
  };
  using ServiceWorkerKeepaliveDataMap =
      std::map<base::Uuid, ServiceWorkerKeepaliveData>;

  static ProcessManager* Get(content::BrowserContext* context);

  // Creates a new ProcessManager for the given `context`. This is independent
  // from the constructor below as it may construct an incognito version of the
  // ProcessManager.
  // Note: Most callers should use `ProcessManager::Get()` instead to retrieve
  // the ProcessManager for a given context.
  static std::unique_ptr<ProcessManager> Create(
      content::BrowserContext* context);

  ProcessManager(content::BrowserContext* context,
                 ExtensionRegistry* registry);

  ProcessManager(const ProcessManager&) = delete;
  ProcessManager& operator=(const ProcessManager&) = delete;

  ~ProcessManager() override;

  // KeyedService support:
  void Shutdown() override;

  void RegisterRenderFrameHost(content::RenderFrameHost* render_frame_host,
                               const Extension* extension);
  void UnregisterRenderFrameHost(content::RenderFrameHost* render_frame_host);

  // Starts tracking or stops tracking (if it's already being tracked) a running
  // worker to this process manager. Note: This does not create any Service
  // Workers.
  void StartTrackingServiceWorkerRunningInstance(const WorkerId& worker_id);
  void StopTrackingServiceWorkerRunningInstance(const WorkerId& worker_id);
  void StopTrackingServiceWorkerRunningInstance(
      const ExtensionId& extension_id,
      int64_t worker_version_id,
      const blink::ServiceWorkerToken& service_worker_token);

  using FrameSet = std::set<content::RenderFrameHost*>;
  const FrameSet GetAllFrames() const;

  // Returns all RenderFrameHosts that are registered for the specified
  // extension.
  ProcessManager::FrameSet GetRenderFrameHostsForExtension(
      const ExtensionId& extension_id);

  bool IsRenderFrameHostRegistered(content::RenderFrameHost* render_frame_host);

  void AddObserver(ProcessManagerObserver* observer);
  void RemoveObserver(ProcessManagerObserver* observer);

  // Creates a new UI-less extension instance.  Like CreateViewHost, but not
  // displayed anywhere.  Returns false if no background host can be created,
  // for example for hosted apps and extensions that aren't enabled in
  // Incognito.
  virtual bool CreateBackgroundHost(const Extension* extension,
                                    const GURL& url);

  // Creates background hosts if the embedder is ready and they are not already
  // loaded.
  void MaybeCreateStartupBackgroundHosts();

  // Gets the ExtensionHost for the background page for an extension, or null if
  // the extension isn't running or doesn't have a background page.
  ExtensionHost* GetBackgroundHostForExtension(const ExtensionId& extension_id);

  // Returns the background page ExtensionHost for the given
  // `render_frame_host`, if `render_frame_host` is in primary main frame and
  // within the extension's background.
  ExtensionHost* GetBackgroundHostForRenderFrameHost(
      content::RenderFrameHost* render_frame_host);

  // Returns true if the (lazy) background host for the given extension has
  // already been sent the unload event and is shutting down.
  bool IsBackgroundHostClosing(const ExtensionId& extension_id);

  // Returns the extension associated with the specified RenderFrameHost,
  // or null.
  const Extension* GetExtensionForRenderFrameHost(
      content::RenderFrameHost* render_frame_host);

  // Returns the extension associated with the main frame of the given
  // `web_contents`, or null if there isn't one.
  const Extension* GetExtensionForWebContents(
      content::WebContents* web_contents);

  // Getter and setter for the lazy background page's keepalive count. This is
  // the count of how many outstanding "things" are keeping the page alive.
  // When this reaches 0, we will begin the process of shutting down the page.
  // "Things" include pending events, resource loads, and API calls.
  // Returns -1 if `extension` does not have a lazy background page.
  // The calls to increment and decrement the count also accept a category
  // of activity and an extra string of data. These are kept so there is
  // more information for the counts. See the Activity struct definition
  // for more details regarding the extra data.
  int GetLazyKeepaliveCount(const Extension* extension);
  void IncrementLazyKeepaliveCount(const Extension* extension,
                                   Activity::Type activity_type,
                                   const std::string& extra_data);

  // Decrements the keepalive count. Returns true if the specified activity was
  // successfully matched and decremented; returns false if the activity was
  // not found or if the keepalive count was already zero.
  bool DecrementLazyKeepaliveCount(const Extension* extension,
                                   Activity::Type activity_type,
                                   const std::string& extra_data);

  // Sends out notification to observers when the extension process is gone.
  void NotifyExtensionProcessTerminated(const Extension* extension);

  // Methods to increment or decrement the ref-count of a specified service
  // worker with id `worker_id`.
  // The increment method returns the guid that needs to be passed to the
  // decrement method.
  // `timeout_type` is the SW's timeout behavior.
  base::Uuid IncrementServiceWorkerKeepaliveCount(
      const WorkerId& worker_id,
      content::ServiceWorkerExternalRequestTimeoutType timeout_type,
      Activity::Type activity_type,
      const std::string& extra_data);
  // Decrements the ref-count of the specified worker with `worker_id` that
  // had its ref-count incremented with `request_uuid`.
  void DecrementServiceWorkerKeepaliveCount(const WorkerId& worker_id,
                                            const base::Uuid& request_uuid,
                                            Activity::Type activity_type,
                                            const std::string& extra_data);

  using ActivitiesMultisetPair = std::pair<Activity::Type, std::string>;
  using ActivitiesMultiset = std::multiset<ActivitiesMultisetPair>;

  // Return the current set of keep-alive activities for the extension.
  ActivitiesMultiset GetLazyKeepaliveActivities(const Extension* extension);

  // Handles a response to the ShouldSuspend message, used for lazy background
  // pages.
  void OnShouldSuspendAck(const ExtensionId& extension_id,
                          uint64_t sequence_id);

  // Tracks network requests for a given RenderFrameHost, used to know
  // when network activity is idle for lazy background pages.
  void NetworkRequestStarted(content::RenderFrameHost* render_frame_host,
                             uint64_t request_id);
  void NetworkRequestDone(content::RenderFrameHost* render_frame_host,
                          uint64_t request_id);

  // Prevents `extension`'s background page from being closed and sends the
  // onSuspendCanceled() event to it.
  void CancelSuspend(const Extension* extension);

  // Called on shutdown to close our extension hosts.
  void CloseBackgroundHosts();

  // Wakes an extension's event page from a suspended state and calls
  // `callback` after it is reactivated.
  //
  // `callback` will be passed true if the extension was reactivated
  // successfully, or false if an error occurred.
  //
  // Returns true if a wake operation was scheduled successfully,
  // or false if the event page was already awake.
  // Callback will be run asynchronously if true, and never run if false.
  bool WakeEventPage(const ExtensionId& extension_id,
                     base::OnceCallback<void(bool)> callback);

  // Sets the time in milliseconds that an extension event page can
  // be idle before it is shut down; must be > 0.
  static void SetEventPageIdleTimeForTesting(unsigned idle_time_msec);

  // Sets the time in milliseconds that an extension event page has
  // between being notified of its impending unload and that unload
  // happening.
  static void SetEventPageSuspendingTimeForTesting(
      unsigned suspending_time_msec);

  content::BrowserContext* browser_context() const { return browser_context_; }

  const ExtensionHostSet& background_hosts() const {
    return background_hosts_;
  }

  // Returns true if this ProcessManager has registered any worker with id
  // `worker_id`.
  bool HasServiceWorker(const WorkerId& worker_id) const;

  // Returns all the Service Worker infos that is active for the extension with
  // `extension_id`.
  std::vector<WorkerId> GetServiceWorkersForExtension(
      const ExtensionId& extension_id) const;

  // Returns the context ID for the given `worker_id`, if `worker_id` is
  // registered in the process manager. Otherwise, returns an empty base::Uuid.
  base::Uuid GetContextIdForWorker(const WorkerId& worker_id) const;

  // Returns the active service worker keepalives for the given `extension_id`.
  // Note: This should be used for debugging and metrics purposes; callers
  // should only interact with the service worker keepalives they themselves
  // created via IncrementServiceWorkerKeepaliveCount().
  std::vector<ServiceWorkerKeepaliveData>
  GetServiceWorkerKeepaliveDataForRecords(
      const ExtensionId& extension_id) const;

  bool startup_background_hosts_created_for_test() const {
    return startup_background_hosts_created_;
  }

  std::vector<WorkerId> GetAllWorkersIdsForTesting();
  void ReleaseLazyKeepaliveCountForFrameForTesting(
      content::RenderFrameHost* render_frame_host);
  void CloseLazyBackgroundPageNowForTesting(const ExtensionId& extension_id);

 protected:
  // Not owned. Also used by IncognitoProcessManager.
  raw_ptr<ExtensionRegistry> extension_registry_;

 private:
  // ExtensionRegistryObserver:
  void OnExtensionLoaded(content::BrowserContext* browser_context,
                         const Extension* extension) override;
  void OnExtensionUnloaded(content::BrowserContext* browser_context,
                           const Extension* extension,
                           UnloadedExtensionReason reason) override;

  // content::RenderProcessHostObserver:
  void RenderProcessExited(
      content::RenderProcessHost* host,
      const content::ChildProcessTerminationInfo& info) override;

  // ExtensionHostObserver:
  void OnExtensionHostDestroyed(ExtensionHost* host) override;

  // Extra information we keep for each extension's background page.
  struct BackgroundPageData;
  struct ExtensionRenderFrameData;
  using BackgroundPageDataMap = std::map<ExtensionId, BackgroundPageData>;
  using ExtensionRenderFrames =
      std::map<content::RenderFrameHost*, ExtensionRenderFrameData>;

  // Load all background pages once the profile data is ready and the pages
  // should be loaded.
  void CreateStartupBackgroundHosts();

  // Called just after `host` is created so it can be registered in our lists.
  void OnBackgroundHostCreated(ExtensionHost* host);

  // Handles a request from a created extension host to close the contents.
  // This happens in cases such as the contents calling `window.close()`.
  void HandleCloseExtensionHost(ExtensionHost* host);

  // Close the given `host` iff it's a background page.
  void CloseBackgroundHost(ExtensionHost* host);

  // If the frame isn't keeping the lazy background page alive, increments the
  // keepalive count to do so.
  void AcquireLazyKeepaliveCountForFrame(
      content::RenderFrameHost* render_frame_host);

  // If the frame is keeping the lazy background page alive, decrements the
  // keepalive count to stop doing it.
  void ReleaseLazyKeepaliveCountForFrame(
      content::RenderFrameHost* render_frame_host);

  // Internal implementation of DecrementLazyKeepaliveCount with an
  // `extension_id` known to have a lazy background page.
  void DecrementLazyKeepaliveCount(const ExtensionId& extension_id);
  bool DecrementLazyKeepaliveCount(const ExtensionId& extension_id,
                                   Activity::Type activity_type,
                                   const std::string& extra_data);

  // These are called when the extension transitions between idle and active.
  // They control the process of closing the background page when idle.
  void OnLazyBackgroundPageIdle(const ExtensionId& extension_id,
                                uint64_t sequence_id);
  void OnLazyBackgroundPageActive(const ExtensionId& extension_id);
  void CloseLazyBackgroundPageNow(const ExtensionId& extension_id,
                                  uint64_t sequence_id);

  const Extension* GetExtensionForAgentHost(
      content::DevToolsAgentHost* agent_host);

  // content::DevToolsAgentHostObserver overrides.
  void DevToolsAgentHostAttached(
      content::DevToolsAgentHost* agent_host) override;
  void DevToolsAgentHostDetached(
      content::DevToolsAgentHost* agent_host) override;

  // Unregister RenderFrameHosts and clear background page data for an extension
  // which has been unloaded.
  void UnregisterExtension(const ExtensionId& extension_id);

  // Clears background page data for this extension.
  void ClearBackgroundPageData(const ExtensionId& extension_id);

  // Handles a response to the SuspendExtension Mojo method, used for lazy
  // background pages.
  void OnSuspendAck(const ExtensionId& extension_id);

  // The set of ExtensionHosts running viewless background extensions.
  ExtensionHostSet background_hosts_;

  // The browser context associated with the ProcessManager.
  raw_ptr<content::BrowserContext> browser_context_;

  // Contains all active extension-related RenderFrameHost instances for all
  // extensions. We also keep a cache of the host's view type, because that
  // information is not accessible at registration/deregistration time.
  ExtensionRenderFrames all_extension_frames_;

  // Contains all active running extension Service Worker information for all
  // extensions.
  WorkerIdSet all_running_extension_workers_;
  // Maps worker IDs to extension context IDs (as used in the runtime API) for
  // running workers.
  std::map<WorkerId, base::Uuid> worker_context_ids_;

  BackgroundPageDataMap background_page_data_;

  // True if we have created the startup set of background hosts.
  bool startup_background_hosts_created_;

  // TODO(crbug.com/484371187): Investigate if reentrancy can be removed.
  base::ObserverList<
      ProcessManagerObserver,
      /*check_empty=*/false,
      base::ObserverListReentrancyPolicy::kAllowReentrancyUntriaged>
      observer_list_;

  // ID Counter used to set ProcessManager::BackgroundPageData close_sequence_id
  // members. These IDs are tracked per extension in background_page_data_ and
  // are used to verify that nothing has interrupted the process of closing a
  // lazy background process.
  //
  // Any interruption obtains a new ID by incrementing
  // last_background_close_sequence_id_ and storing it in background_page_data_
  // for a particular extension. Callbacks and round-trip IPC messages store the
  // value of the extension's close_sequence_id at the beginning of the process.
  // Thus comparisons can be done to halt when IDs no longer match.
  //
  // This counter provides unique IDs even when BackgroundPageData objects are
  // reset.
  uint64_t last_background_close_sequence_id_;

  // Tracks pending network requests by opaque ID. This is used to ensure proper
  // keepalive counting in response to request status updates; e.g., if an
  // extension URLRequest is constructed and then destroyed without ever
  // starting, we can receive a completion notification without a corresponding
  // start notification. In that case we want to avoid decrementing keepalive.
  std::map<int, raw_ptr<ExtensionHost, CtnExperimental>>
      pending_network_requests_;

  // Observers of Service Worker RPH this ProcessManager manages.
  base::ScopedMultiSourceObservation<content::RenderProcessHost,
                                     content::RenderProcessHostObserver>
      process_observations_{this};
  // Maps render render_process_id -> extension_id for all Service Workers this
  // ProcessManager manages.
  std::map<content::ChildProcessId, std::set<ExtensionId>>
      worker_process_to_extension_ids_;

  // A map of the active service worker keepalives.
  ServiceWorkerKeepaliveDataMap service_worker_keepalives_;

  // Must be last member, see doc on WeakPtrFactory.
  base::WeakPtrFactory<ProcessManager> weak_ptr_factory_{this};
};

}  // namespace extensions

#endif  // EXTENSIONS_BROWSER_PROCESS_MANAGER_H_