Create a new print backend for the updated CUPS APIs

printing/backend/cups_printer.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef PRINTING_BACKEND_CUPS_PRINTER_H_
+#define PRINTING_BACKEND_CUPS_PRINTER_H_
+
+#include <cups/cups.h>
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "printing/backend/cups_deleters.h"
+#include "printing/printing_export.h"
+#include "url/gurl.h"
+
+namespace base {
+class FilePath;
+}
+
+namespace printing {
+
+struct PrinterBasicInfo;
+
+// Provides information regarding cups options.
+class PRINTING_EXPORT CupsOptionProvider {
+ public:
+  virtual ~CupsOptionProvider() = default;
+
+  // Returns the supported ipp attributes for the given |option_name|.
+  // ipp_attribute_t* is owned by CupsOptionProvider.
+  virtual ipp_attribute_t* GetSupportedOptionValues(
+      base::StringPiece option_name) const = 0;
+
+  // Returns supported attribute values for |option_name| where the value can be
+  // convered to a string.
+  virtual std::vector<base::StringPiece> GetSupportedOptionValueStrings(
+      base::StringPiece option_name) const = 0;
+
+  // Returns the default ipp attributes for the given |option_name|.
+  // ipp_attribute_t* is owned by CupsOptionProvider.
+  virtual ipp_attribute_t* GetDefaultOptionValue(
+      base::StringPiece option_name) const = 0;
+
+  // Returns true if the |value| is supported by option |name|.
+  virtual bool CheckOptionSupported(base::StringPiece name,
+                                    base::StringPiece value) const = 0;
+};
+
+// Represents a CUPS printer.
+// Retrieves information from CUPS printer objects as requested.  This class
+// is only valid as long as the CupsConnection which created it exists as they
+// share an http connection which the CupsConnection closes on destruction.
+class PRINTING_EXPORT CupsPrinter : public CupsOptionProvider {
+ public:
+  // Create a printer with a connection defined by |http| and |dest|.  |info|
+  // can be null and will be
+  // lazily initialized when needed.

[Lei Zhang, 2016/07/21 20:31:30]

Combine with previous line. If you are using "git cl format" to automagically
fix formatting, be aware that it won't fix this because it doesn't want to
accidentally ruin anyone's ASCII art.

[skau, 2016/07/21 23:33:10]

I have been using git cl format.  Thanks.

+  CupsPrinter(http_t* http,
+              std::unique_ptr<cups_dest_t, DestinationDeleter> dest,
+              std::unique_ptr<cups_dinfo_t, DestInfoDeleter> info);
+
+  CupsPrinter(CupsPrinter&& printer);
+
+  ~CupsPrinter() override;
+
+  // Returns true if this is the default printer
+  bool is_default() const;
+
+  // CupsOptionProvider
+  ipp_attribute_t* GetSupportedOptionValues(
+      base::StringPiece option_name) const override;
+  std::vector<base::StringPiece> GetSupportedOptionValueStrings(
+      base::StringPiece option_name) const override;
+  ipp_attribute_t* GetDefaultOptionValue(
+      base::StringPiece option_name) const override;
+  bool CheckOptionSupported(base::StringPiece name,
+                            base::StringPiece value) const override;
+
+  // Returns the file name for the PPD retrieved from the print server.
+  base::FilePath GetPPD() const;
+
+  // Returns the name of the printer as configured in CUPS
+  std::string GetName() const;
+
+  std::string GetMakeAndModel() const;
+
+  // Returns true if the printer is currently reachable and working.
+  bool IsAvailable() const;
+
+  // Populates |basic_info| with the relevant information about the printer
+  bool ToPrinterInfo(PrinterBasicInfo* basic_info) const;
+
+  // Start a print job.  Writes the id of the started job to |job_id|.  |job_id|
+  // is 0 if there is an error.  Check availability before using this operation.
+  // Usage on an unavailable printer is undefined.
+  ipp_status_t CreateJob(int* job_id,
+                         base::StringPiece job_title,
+                         const std::vector<cups_option_t>& options);
+
+  // Add a document to a print job.  |job_id| must be non-zero and refer to a
+  // job started with CreateJob.  |document_name| will be displayed in print
+  // status.  |last_doc| should be true if this is the last document for this
+  // print job.  |options| should be IPP key value pairs for the Send-Document
+  // operation.
+  bool StartDocument(int job_id,
+                     base::StringPiece document_name,
+                     bool last_doc,
+                     const std::vector<cups_option_t>& options);
+
+  // Add data to the current document started by StartDocument.  Calling this
+  // without a started document will fail.
+  bool StreamData(const std::vector<char>& buffer);
+
+  // Finish the current document.  Another document can be added or the job can
+  // be closed to complete printing.
+  bool FinishDocument();
+
+  // Close the job.  If the job is not closed, the documents will not be
+  // printed.  |job_id| should match the id from CreateJob.
+  ipp_status_t CloseJob(int job_id);
+
+ private:
+  // Lazily initialize dest info as it can require a network call
+  bool InitializeDestInfo() const;
+
+  // http connection owned by the CupsConnection which created this object
+  http_t* const cups_http_;
+
+  // information to identify a printer
+  std::unique_ptr<cups_dest_t, DestinationDeleter> destination_;
+
+  // opaque object containing printer attributes and options
+  mutable std::unique_ptr<cups_dinfo_t, DestInfoDeleter> dest_info_;
+
+  DISALLOW_COPY_AND_ASSIGN(CupsPrinter);
+};
+
+}  // namespace printing
+
+#endif  // PRINTING_BACKEND_CUPS_PRINTER_H_