Print directly to CUPS using the IPP APIs

printing/printing_context_chromeos.cc

+// 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.
+
+#include "printing/printing_context_chromeos.h"
+
+#include <cups/cups.h>
+#include <stdint.h>
+#include <unicode/ulocdata.h>
+
+#include <memory>
+#include <utility>
+#include <vector>
+
+#include "base/logging.h"
+#include "base/memory/ptr_util.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
+#include "base/strings/utf_string_conversions.h"
+#include "printing/backend/cups_connection.h"
+#include "printing/backend/cups_ipp_util.h"
+#include "printing/backend/cups_printer.h"
+#include "printing/metafile.h"
+#include "printing/print_job_constants.h"
+#include "printing/print_settings.h"
+#include "printing/printing_context_no_system_dialog.h"
+#include "printing/units.h"
+
+namespace printing {
+
+namespace {
+
+using CupsOption = std::unique_ptr<cups_option_t, OptionDeleter>;

[Lei Zhang, 2016/07/25 21:06:04]

Can you name this ScopedCupsOption, so it's more obvious that this is a smart
pointer?

[skau, 2016/07/27 00:16:47]

Done.

+
+// convert from a ColorMode setting to a print-color-mode value from PWG 5100.13
+const char* GetColorModelForMode(int color_mode) {
+  const char* mode_string;
+  switch (color_mode) {
+    case COLOR:
+    case CMYK:
+    case CMY:
+    case KCMY:
+    case CMY_K:
+    case RGB:
+    case RGB16:
+    case RGBA:
+    case COLORMODE_COLOR:
+    case HP_COLOR_COLOR:
+    case PRINTOUTMODE_NORMAL:
+    case PROCESSCOLORMODEL_CMYK:
+    case PROCESSCOLORMODEL_RGB:
+      mode_string = CUPS_PRINT_COLOR_MODE_COLOR;
+      break;
+    case GRAY:
+    case BLACK:
+    case GRAYSCALE:
+    case COLORMODE_MONOCHROME:
+    case HP_COLOR_BLACK:
+    case PRINTOUTMODE_NORMAL_GRAY:
+    case PROCESSCOLORMODEL_GREYSCALE:
+      mode_string = CUPS_PRINT_COLOR_MODE_MONOCHROME;
+      break;
+    default:
+      mode_string = nullptr;
+      LOG(WARNING) << "Unrecognized color mode";
+      break;
+  }
+
+  return mode_string;
+}
+
+// Copies the contents |value| into a newly allocated char* buffer.  The result
+// is null terminated and will need to be deleted.

[Lei Zhang, 2016/07/25 21:06:04]

The more common phrase here would be "the caller owns the returned string."

[skau, 2016/07/27 00:16:47]

Done.

+char* ToCString(const base::StringPiece value) {

[Lei Zhang, 2016/07/25 21:06:04]

TOCString() -> more like, DuplicateString() ?

[skau, 2016/07/27 00:16:47]

Done.

+  size_t buffer_size = value.size() + 1;
+  char* dst = new char[buffer_size];
+  strncpy(dst, value.as_string().c_str(), buffer_size);
+  return dst;
+}
+
+CupsOption ConstructOption(const base::StringPiece name,
+                           const base::StringPiece value) {
+  CupsOption option = CupsOption(new cups_option_t);
+  option->name = ToCString(name);

[Lei Zhang, 2016/07/25 21:06:04]

It's probably not obvious to readers that CupsOption is going delete the
name/value here. Even reading the cupsFreeOptions() documentation is not
completely obvious and I had to peek at the cupsFreeOptions() source code to see
what it does. So a comment here to say (Scoped)CupsOption will delete the
strings is helpful.

[skau, 2016/07/27 00:16:47]

Done.

+  option->value = ToCString(value);
+  return option;
+}
+
+base::StringPiece GetCollateString(bool collate) {
+  return collate ? kCollated : kUncollated;
+}
+
+std::vector<CupsOption> SettingsToCupsOptions(const PrintSettings& settings) {
+  const char* sides = nullptr;
+  switch (settings.duplex_mode()) {
+    case SIMPLEX:
+      sides = CUPS_SIDES_ONE_SIDED;
+      break;
+    case LONG_EDGE:
+      sides = CUPS_SIDES_TWO_SIDED_PORTRAIT;
+      break;
+    case SHORT_EDGE:
+      sides = CUPS_SIDES_TWO_SIDED_LANDSCAPE;
+      break;
+    default:
+      NOTREACHED();
+  }
+
+  std::vector<CupsOption> options;
+  options.push_back(
+      ConstructOption(kIppColor,
+                      GetColorModelForMode(settings.color())));  // color
+  options.push_back(ConstructOption(kIppDuplex, sides));         // duplexing
+  options.push_back(
+      ConstructOption(kIppMedia,
+                      settings.requested_media().vendor_id));  // paper size
+  options.push_back(
+      ConstructOption(kIppCopies,
+                      base::IntToString(settings.copies())));  // copies
+  options.push_back(
+      ConstructOption(kIppCollate,
+                      GetCollateString(settings.collate())));  // collate
+
+  return options;
+}
+
+void SetPrintableArea(PrintSettings* settings,
+                      const PrintSettings::RequestedMedia& media,
+                      bool flip) {
+  if (!media.size_microns.IsEmpty()) {
+    float deviceMicronsPerDeviceUnit =
+        (kHundrethsMMPerInch * 10.0f) / settings->device_units_per_inch();
+    gfx::Size paper_size =
+        gfx::Size(media.size_microns.width() / deviceMicronsPerDeviceUnit,
+                  media.size_microns.height() / deviceMicronsPerDeviceUnit);
+
+    gfx::Rect paper_rect(0, 0, paper_size.width(), paper_size.height());
+    settings->SetPrinterPrintableArea(paper_size, paper_rect, flip);
+  }
+}
+
+}  // namespace
+
+// static
+std::unique_ptr<PrintingContext> PrintingContext::Create(Delegate* delegate) {
+  if (PrintBackend::GetNativeCupsEnabled())
+    return base::MakeUnique<PrintingContextChromeos>(delegate);
+
+  return base::MakeUnique<PrintingContextNoSystemDialog>(delegate);
+}
+
+PrintingContextChromeos::PrintingContextChromeos(Delegate* delegate)
+    : PrintingContext(delegate),
+      connection_(GURL(), HTTP_ENCRYPT_NEVER, true) {}
+
+PrintingContextChromeos::~PrintingContextChromeos() {
+  ReleaseContext();
+}
+
+void PrintingContextChromeos::AskUserForSettings(
+    int max_pages,
+    bool has_selection,
+    bool is_scripted,
+    const PrintSettingsCallback& callback) {
+  // We don't want to bring up a dialog here.  Ever.  Just signal the callback.
+  callback.Run(OK);
+}
+
+PrintingContext::Result PrintingContextChromeos::UseDefaultSettings() {
+  DCHECK(!in_print_job_);
+
+  ResetSettings();
+
+  std::string device_name = base::UTF16ToUTF8(settings_.device_name());
+  if (device_name.empty())
+    return OnError();
+
+  // TODO(skau): https://crbug.com/613779. See UpdatePrinterSettings for more
+  // info.
+  if (settings_.dpi() == 0) {
+    DVLOG(1) << "Using Default DPI";
+    settings_.set_dpi(kDefaultPdfDpi);
+  }
+
+  // Retrieve device information and set it
+  if (InitializeDevice(device_name) != OK) {
+    LOG(ERROR) << "Could not initialize printer";
+    return OnError();
+  }
+
+  // Set printable area
+  DCHECK(printer_);
+  PrinterSemanticCapsAndDefaults::Paper paper = DefaultPaper(*printer_);
+
+  PrintSettings::RequestedMedia media;
+  media.vendor_id = paper.vendor_id;
+  media.size_microns = paper.size_um;
+  settings_.set_requested_media(media);
+
+  SetPrintableArea(&settings_, media, true /* flip landscape */);
+
+  return OK;
+}
+
+gfx::Size PrintingContextChromeos::GetPdfPaperSizeDeviceUnits() {
+  int32_t width = 0;
+  int32_t height = 0;
+  UErrorCode error = U_ZERO_ERROR;
+  ulocdata_getPaperSize(delegate_->GetAppLocale().c_str(), &height, &width,
+                        &error);
+  if (error > U_ZERO_ERROR) {
+    // If the call failed, assume a paper size of 8.5 x 11 inches.
+    LOG(WARNING) << "ulocdata_getPaperSize failed, using 8.5 x 11, error: "
+                 << error;
+    width =
+        static_cast<int>(kLetterWidthInch * settings_.device_units_per_inch());
+    height =
+        static_cast<int>(kLetterHeightInch * settings_.device_units_per_inch());
+  } else {
+    // ulocdata_getPaperSize returns the width and height in mm.
+    // Convert this to pixels based on the dpi.
+    float multiplier = 100 * settings_.device_units_per_inch();
+    multiplier /= kHundrethsMMPerInch;
+    width *= multiplier;
+    height *= multiplier;
+  }
+  return gfx::Size(width, height);
+}
+
+PrintingContext::Result PrintingContextChromeos::UpdatePrinterSettings(
+    bool external_preview,
+    bool show_system_dialog,
+    int page_count) {
+  DCHECK(!show_system_dialog);
+
+  if (InitializeDevice(base::UTF16ToUTF8(settings_.device_name())) != OK)
+    return OnError();
+
+  // TODO(skau): Convert to DCHECK when https://crbug.com/613779 is resolved
+  // Print quality suffers when this is set to the resolution reported by the
+  // printer but print quality is fine at this resolution. UseDefaultSettings
+  // exhibits the same problem.
+  if (settings_.dpi() == 0) {
+    DVLOG(1) << "Using Default DPI";
+    settings_.set_dpi(kDefaultPdfDpi);
+  }
+
+  // compute paper size
+  PrintSettings::RequestedMedia media = settings_.requested_media();
+
+  if (media.IsDefault()) {
+    DCHECK(printer_);
+    PrinterSemanticCapsAndDefaults::Paper paper = DefaultPaper(*printer_);
+
+    media.vendor_id = paper.vendor_id;
+    media.size_microns = paper.size_um;
+    settings_.set_requested_media(media);
+  }
+
+  SetPrintableArea(&settings_, media, true);
+
+  return OK;
+}
+
+PrintingContext::Result PrintingContextChromeos::InitializeDevice(
+    const std::string& device) {
+  DCHECK(!in_print_job_);
+
+  std::unique_ptr<CupsPrinter> printer = connection_.GetPrinter(device);
+  if (!printer) {
+    LOG(WARNING) << "Could not initialize device";
+    return OnError();
+  }
+
+  printer_ = std::move(printer);
+
+  return OK;
+}
+
+PrintingContext::Result PrintingContextChromeos::InitWithSettings(
+    const PrintSettings& settings) {
+  DCHECK(!in_print_job_);
+
+  settings_ = settings;
+
+  return OK;
+}
+
+PrintingContext::Result PrintingContextChromeos::NewDocument(
+    const base::string16& document_name) {
+  DCHECK(!in_print_job_);
+  in_print_job_ = true;
+
+  std::string converted_name = base::UTF16ToUTF8(document_name);
+  std::string title = base::UTF16ToUTF8(settings_.title());
+  std::vector<CupsOption> cups_options = SettingsToCupsOptions(settings_);
+
+  bool all_supported = true;
+
+  for (const CupsOption& option : cups_options) {
+    bool supported =
+        printer_->CheckOptionSupported(option->name, option->value);
+    all_supported = all_supported && supported;
+  }
+
+  if (!all_supported) {
+    DVLOG(1) << "Unsupported options detected";
+    return OnError();
+  }
+
+  std::vector<cups_option_t> options;
+  for (const CupsOption& option : cups_options) {
+    options.push_back(*(option.get()));
+  }
+
+  ipp_status_t create_status = printer_->CreateJob(&job_id_, title, options);
+
+  if (job_id_ == 0) {
+    DLOG(WARNING) << "Creating cups job failed"
+                  << ippErrorString(create_status);
+    return OnError();
+  }
+
+  // we only send one document, so it's always the last one
+  if (!printer_->StartDocument(job_id_, converted_name, true, options)) {
+    LOG(ERROR) << "Starting document failed";
+    return OnError();
+  }
+
+  return OK;
+}
+
+PrintingContext::Result PrintingContextChromeos::NewPage() {
+  if (abort_printing_)
+    return CANCEL;
+
+  DCHECK(in_print_job_);
+
+  // Intentional No-op.
+
+  return OK;
+}
+
+PrintingContext::Result PrintingContextChromeos::PageDone() {
+  if (abort_printing_)
+    return CANCEL;
+
+  DCHECK(in_print_job_);
+
+  // Intentional No-op.
+
+  return OK;
+}
+
+PrintingContext::Result PrintingContextChromeos::DocumentDone() {
+  if (abort_printing_)
+    return CANCEL;
+
+  DCHECK(in_print_job_);
+
+  if (!printer_->FinishDocument()) {
+    LOG(WARNING) << "Finishing document failed";
+    return OnError();
+  }
+
+  ipp_status_t job_status = printer_->CloseJob(job_id_);
+  job_id_ = 0;
+
+  if (job_status != IPP_STATUS_OK) {
+    LOG(WARNING) << "Closing job failed";
+    return OnError();
+  }
+
+  ResetSettings();
+  return OK;
+}
+
+void PrintingContextChromeos::Cancel() {
+  abort_printing_ = true;
+  in_print_job_ = false;
+}
+
+void PrintingContextChromeos::ReleaseContext() {
+  printer_.reset();
+}
+
+gfx::NativeDrawingContext PrintingContextChromeos::context() const {
+  // Intentional No-op.
+  return nullptr;
+}
+
+PrintingContext::Result PrintingContextChromeos::StreamData(
+    const std::vector<char>& buffer) {
+  if (abort_printing_)
+    return CANCEL;
+
+  DCHECK(in_print_job_);
+  DCHECK(printer_);
+
+  if (!printer_->StreamData(buffer))
+    return OnError();
+
+  return OK;
+}
+
+}  // namespace printing