chrome/browser/printing/print_job_worker_oop.h

// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROME_BROWSER_PRINTING_PRINT_JOB_WORKER_OOP_H_
#define CHROME_BROWSER_PRINTING_PRINT_JOB_WORKER_OOP_H_

#include <memory>
#include <optional>
#include <string>

#include "base/memory/weak_ptr.h"
#include "build/build_config.h"
#include "chrome/browser/printing/print_backend_service_manager.h"
#include "chrome/browser/printing/print_job_worker.h"
#include "chrome/services/printing/public/mojom/print_backend_service.mojom.h"
#include "components/enterprise/buildflags/buildflags.h"
#include "printing/buildflags/buildflags.h"
#include "printing/mojom/print.mojom.h"

#if !BUILDFLAG(ENABLE_OOP_PRINTING)
#error "OOP printing must be enabled"
#endif

namespace printing {

class PrintedDocument;

// Worker thread code. It manages the PrintingContext and offloads all system
// driver interactions to the Print Backend service.  This is the object that
// generates most NOTIFY_PRINT_JOB_EVENT notifications, but they are generated
// through a NotificationTask task to be executed from the right thread, the UI
// thread.  PrintJob always outlives its worker instance.
class PrintJobWorkerOop : public PrintJobWorker {
 public:
  // The `client_id` specifies the print document client registered with
  // `PrintBackendServiceManager`.  `PrintJobWorkerOop` takes responsibility
  // for unregistering the client ID with `PrintBackendServiceManager` once
  // printing is completed.
  // The `client_id` can be empty.  This can occur for placeholder print jobs
  // that don't actually initiate printing such as during content analysis.
  PrintJobWorkerOop(
      std::unique_ptr<PrintingContext::Delegate> printing_context_delegate,
      std::unique_ptr<PrintingContext> printing_context,
      std::optional<PrintBackendServiceManager::ClientId> client_id,
      std::optional<PrintBackendServiceManager::ContextId> context_id,
      PrintJob* print_job,
      bool print_from_system_dialog);
  PrintJobWorkerOop(const PrintJobWorkerOop&) = delete;
  PrintJobWorkerOop& operator=(const PrintJobWorkerOop&) = delete;
  ~PrintJobWorkerOop() override;

  // `PrintJobWorker` overrides.
  void StartPrinting(PrintedDocument* new_document) override;
  void Cancel() override;
#if BUILDFLAG(ENTERPRISE_CONTENT_ANALYSIS)
  void CleanupAfterContentAnalysisDenial() override;
#endif

 protected:
  // For testing.
  PrintJobWorkerOop(
      std::unique_ptr<PrintingContext::Delegate> printing_context_delegate,
      std::unique_ptr<PrintingContext> printing_context,
      std::optional<PrintBackendServiceManager::ClientId> client_id,
      std::optional<PrintBackendServiceManager::ContextId> context_id,
      PrintJob* print_job,
      bool print_from_system_dialog,
      bool simulate_spooling_memory_errors);

  // Local callback wrappers for Print Backend Service mojom call.  Virtual to
  // support testing.
  virtual void OnDidStartPrinting(mojom::ResultCode result, int job_id);
#if BUILDFLAG(IS_WIN)
  virtual void OnDidRenderPrintedPage(uint32_t page_index,
                                      mojom::ResultCode result);
#endif
  virtual void OnDidRenderPrintedDocument(mojom::ResultCode result);
  virtual void OnDidDocumentDone(int job_id, mojom::ResultCode result);
  virtual void OnDidCancel(scoped_refptr<PrintJob> job,
                           mojom::ResultCode cancel_reason);

  // `PrintJobWorker` overrides.
#if BUILDFLAG(IS_WIN)
  bool SpoolPage(PrintedPage* page) override;
#endif
  bool SpoolDocument() override;
  void OnDocumentDone() override;
  void FinishDocumentDone(int job_id) override;
  void OnCancel() override;
  void OnFailure() override;

 private:
  // Support to unregister this worker as a printing client.  Applicable any
  // time a print job finishes, is canceled, or needs to be restarted.
  void UnregisterServiceManagerClient();

  // Helper function for restarting a print job after error.
  bool TryRestartPrinting();

  // Initiate failure handling, including notification to the user.
  void NotifyFailure(mojom::ResultCode result);

  // Mojo support to send messages from UI thread.
  void SendEstablishPrintingContext();
  void SendStartPrinting(const std::string& device_name,
                         const std::u16string& document_name);
#if BUILDFLAG(IS_WIN)
  void SendRenderPrintedPage(
      const PrintedPage* page,
      mojom::MetafileDataType page_data_type,
      base::ReadOnlySharedMemoryRegion serialized_page_data);
#endif  // BUILDFLAG(IS_WIN)
  void SendRenderPrintedDocument(
      mojom::MetafileDataType data_type,
      base::ReadOnlySharedMemoryRegion serialized_data);
  void SendDocumentDone();
  void SendCancel(base::OnceClosure on_did_cancel_callback);

  // Used to test spooling memory error handling.
  const bool simulate_spooling_memory_errors_;

  // Client ID with the print backend service manager for this print job.
  // Used only from UI thread.
  std::optional<PrintBackendServiceManager::ClientId>
      service_manager_client_id_;

  // The printing context identifier related to this print job.
  // Used only from UI thread.
  std::optional<PrintBackendServiceManager::ContextId> printing_context_id_;

  // The device name used when printing via a service.  Used only from the UI
  // thread.
  std::string device_name_;

  // The processed name of the document being printed.  Used only from the UI
  // thread.
  std::u16string document_name_;

  // The printed document. Only has read-only access.  This reference separate
  // from the one already in the base class provides a guarantee that the
  // `PrintedDocument` will persist until OOP processing completes, even if
  // the `PrintJob` should drop its reference as part of failure/cancel
  // processing.  Named differently than base (even though both are private)
  // to avoid any potential confusion between them.
  // Once set at the start of printing on the worker thread, it is only
  // referenced thereafter from the UI thread.  UI thread accesses only occur
  // once the interactions with the Print Backend service occur as a result of
  // starting to print the job.  Any document access from worker thread happens
  // by methods in base class, which use the base `document_` field.
  scoped_refptr<PrintedDocument> document_oop_;

  // Indicates if the print job was initiated from the print system dialog.
  const bool print_from_system_dialog_;

#if BUILDFLAG(IS_WIN)
  // Number of pages that have completed printing.
  uint32_t pages_printed_count_ = 0;
#endif

  // Tracks if a restart for printing has already been attempted.
  bool print_retried_ = false;

  // Tracks if the service has already been requested to cancel printing the
  // document
  bool print_cancel_requested_ = false;

  // Weak pointers have flags that get bound to the thread where they are
  // checked, so it is necessary to use different factories when getting a
  // weak pointer to send to the worker task runner vs. to the UI thread.
  base::WeakPtrFactory<PrintJobWorkerOop> worker_weak_factory_{this};
  base::WeakPtrFactory<PrintJobWorkerOop> ui_weak_factory_{this};
};

}  // namespace printing

#endif  // CHROME_BROWSER_PRINTING_PRINT_JOB_WORKER_OOP_H_