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| 1 // Copyright 2017 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. |
| 4 |
| 5 #include "chrome/browser/chromeos/printing/printer_discoverer.h" |
| 6 |
| 7 #include "base/bind.h" |
| 8 #include "base/memory/ptr_util.h" |
| 9 #include "base/memory/weak_ptr.h" |
| 10 #include "base/observer_list.h" |
| 11 #include "base/scoped_observer.h" |
| 12 #include "base/threading/sequenced_task_runner_handle.h" |
| 13 #include "chrome/browser/chromeos/printer_detector/printer_detector.h" |
| 14 #include "chrome/browser/chromeos/printer_detector/printer_detector_factory.h" |
| 15 #include "chrome/browser/chromeos/printing/printers_manager.h" |
| 16 #include "chrome/browser/chromeos/printing/printers_manager_factory.h" |
| 17 #include "chrome/browser/profiles/profile.h" |
| 18 #include "chromeos/printing/printer_configuration.h" |
| 19 |
| 20 namespace chromeos { |
| 21 namespace { |
| 22 |
| 23 // Implementation of PrinterDiscoverer interface. |
| 24 class PrinterDiscovererImpl : public PrinterDiscoverer, |
| 25 public PrinterDetector::Observer { |
| 26 public: |
| 27 explicit PrinterDiscovererImpl(Profile* profile) |
| 28 : detector_observer_(this), profile_(profile), weak_ptr_factory_(this) { |
| 29 PrinterDetector* detector = |
| 30 PrinterDetectorFactory::GetInstance()->Get(profile); |
| 31 DCHECK(detector); |
| 32 detector_observer_.Add(detector); |
| 33 usb_printers_ = detector->GetPrinters(); |
| 34 } |
| 35 ~PrinterDiscovererImpl() override = default; |
| 36 |
| 37 // PrinterDiscoverer interface function. |
| 38 void AddObserver(PrinterDiscoverer::Observer* observer) override { |
| 39 observer_list_.AddObserver(observer); |
| 40 // WrappedOnPrintersFound is a simple wrapper around |
| 41 // Observer::OnPrintersFound which lets us safely do the initial |
| 42 // OnPrintersFound call to the registered observer. This wrapper buys us |
| 43 // weak_ptr semantics on 'this', and also guards against removal of the |
| 44 // observer from the Discoverer before this callback is issued. |
| 45 base::SequencedTaskRunnerHandle::Get()->PostTask( |
| 46 FROM_HERE, base::Bind(&PrinterDiscovererImpl::WrappedOnPrintersFound, |
| 47 weak_ptr_factory_.GetWeakPtr(), observer, |
| 48 GetAvailablePrinters())); |
| 49 } |
| 50 |
| 51 // PrinterDiscoverer interface function. |
| 52 void RemoveObserver(PrinterDiscoverer::Observer* observer) override { |
| 53 observer_list_.RemoveObserver(observer); |
| 54 } |
| 55 |
| 56 // PrinterDetector::Observer interface function. |
| 57 void OnAvailableUsbPrintersChanged( |
| 58 const std::vector<Printer>& printers) override { |
| 59 usb_printers_ = printers; |
| 60 std::vector<Printer> all_printers = GetAvailablePrinters(); |
| 61 for (PrinterDiscoverer::Observer& observer : observer_list_) { |
| 62 observer.OnPrintersFound(all_printers); |
| 63 } |
| 64 } |
| 65 |
| 66 private: |
| 67 // Wrapper for doing the initial OnPrintersFound call on an observer of this |
| 68 // object. |
| 69 void WrappedOnPrintersFound(PrinterDiscoverer::Observer* observer, |
| 70 const std::vector<Printer>& printers) { |
| 71 if (observer_list_.HasObserver(observer)) { |
| 72 observer->OnPrintersFound(printers); |
| 73 // Since USB is the only thing we're worried about at the moment, and we |
| 74 // don't have to wait for those printers to be scanned, we can just tell |
| 75 // the observer the initial scan is done now. This will change when we're |
| 76 // also doing network discovery -- we'll hold off on issuing this callback |
| 77 // until the network discovery is done as well. |
| 78 observer->OnDiscoveryInitialScanDone(); |
| 79 } |
| 80 } |
| 81 |
| 82 // Get the current set of discovered printers that are not already known |
| 83 // to the user's PrintersManager. |
| 84 std::vector<Printer> GetAvailablePrinters() { |
| 85 // Only know about usb printers for now. Eventually we'll add discovered |
| 86 // network printers as well. |
| 87 std::vector<Printer> ret; |
| 88 PrintersManager* printers_manager = |
| 89 PrintersManagerFactory::GetForBrowserContext(profile_); |
| 90 if (!printers_manager) { |
| 91 LOG(WARNING) << "Failing to get available printers because no " |
| 92 "PrintersManager exists."; |
| 93 return ret; |
| 94 } |
| 95 |
| 96 for (const Printer& printer : usb_printers_) { |
| 97 if (printers_manager->GetPrinter(printer.id()).get() == nullptr) { |
| 98 ret.push_back(printer); |
| 99 } |
| 100 } |
| 101 return ret; |
| 102 } |
| 103 |
| 104 std::vector<Printer> usb_printers_; |
| 105 base::ObserverList<PrinterDiscoverer::Observer> observer_list_; |
| 106 ScopedObserver<PrinterDetector, PrinterDetector::Observer> detector_observer_; |
| 107 Profile* profile_; |
| 108 base::WeakPtrFactory<PrinterDiscovererImpl> weak_ptr_factory_; |
| 109 }; |
| 110 |
| 111 } // namespace |
| 112 |
| 113 // static |
| 114 std::unique_ptr<PrinterDiscoverer> PrinterDiscoverer::CreateForProfile( |
| 115 Profile* profile) { |
| 116 return base::MakeUnique<PrinterDiscovererImpl>(profile); |
| 117 } |
| 118 |
| 119 } // namespace chromeos |
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