nsPrinterListBase.h

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef nsPrinterListBase_h__

#define nsPrinterListBase_h__

#include "nsIPrinterList.h"

#include "nsCycleCollectionParticipant.h"

#include "nsISupportsImpl.h"

#include "nsPaper.h"

#include "nsString.h"

class nsPrinterListBase : public nsIPrinterList {

 public:

  using Promise = mozilla::dom::Promise;

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS

  NS_DECL_CYCLE_COLLECTION_CLASS(nsPrinterListBase)

  NS_IMETHOD GetSystemDefaultPrinterName(nsAString& aName) final {

    return SystemDefaultPrinterName(aName);

  NS_IMETHOD GetPrinters(JSContext*, Promise**) final;

  NS_IMETHOD GetPrinterByName(const nsAString& aPrinterName, JSContext* aCx,

                              Promise** aResult) final;

  NS_IMETHOD GetPrinterBySystemName(const nsAString& aPrinterName,

                                    JSContext* aCx, Promise** aResult) final;

  NS_IMETHOD GetNamedOrDefaultPrinter(const nsAString& aPrinterName,

                                      JSContext* aCx, Promise** aResult) final;

  NS_IMETHOD GetFallbackPaperList(JSContext*, Promise**) final;

  struct PrinterInfo {

    // Both windows and CUPS: The name of the printer.

    nsString mName;

    // CUPS only: Handle to owned cups_dest_t.

    void* mCupsHandle = nullptr;

};

  // Called off the main thread, collect information to create an appropriate

  // list of printers.

  virtual nsTArray<PrinterInfo> Printers() const = 0;

  // Create an nsIPrinter object given the information we obtained from the

  // background thread.

  virtual RefPtr<nsIPrinter> CreatePrinter(PrinterInfo) const = 0;

  mozilla::Maybe<PrinterInfo> NamedOrDefaultPrinter(nsString aName) const;

  // No copy or move, we're an identity.

  nsPrinterListBase(const nsPrinterListBase&) = delete;

  nsPrinterListBase(nsPrinterListBase&&) = delete;

 protected:

  nsPrinterListBase();

  virtual ~nsPrinterListBase();

  // This could be implemented in terms of Printers() and then searching the

  // returned printer info for a printer of the given name, but we expect

  // backends to have more efficient methods of implementing this.

  virtual mozilla::Maybe<PrinterInfo> PrinterByName(nsString aName) const = 0;

  // Same as NamedPrinter, but uses the system name.

  // Depending on whether or not there is a more efficient way to address the

  // printer for a given backend, this may or may not be equivalent to

  // NamedPrinter.

  virtual mozilla::Maybe<PrinterInfo> PrinterBySystemName(

      nsString aName) const = 0;

  // This is implemented separately from the IDL interface version so that it

  // can be made const, which allows it to be used while resolving promises.

  virtual nsresult SystemDefaultPrinterName(nsAString&) const = 0;

  // Return "paper" sizes to be supported by the Save to PDF destination;

  // for actual printer drivers the list is retrieved from nsIPrinter.

  nsTArray<RefPtr<nsPaper>> FallbackPaperList() const;

  // Constructs mCommonPaperInfo by localizing the sizes in

  // nsPaper::kCommonPaperSizes and creating corresponding PaperInfo.

  void EnsureCommonPaperInfo(JSContext* aCx);

  RefPtr<Promise> mPrintersPromise;

  // PaperInfo for our fallback sizes and common size localization.

  // This field contains the same data for every instance of this class.

  // It's unfortunate that this needs to be a member rather than static data

  // like nsPaper::kCommonPaperSizes, but that's because PaperInfo contains

  // localized data, and we need a JSContext to do the localization.

  RefPtr<const mozilla::CommonPaperInfoArray> mCommonPaperInfo;

};

#endif