Create a new print backend for the updated CUPS APIs

printing/backend/cups_ipp_util.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/backend/cups_ipp_util.h"
+
+#include <cups/cups.h>
+
+#include <algorithm>
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/logging.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_piece.h"
+#include "base/strings/string_split.h"
+#include "base/strings/string_util.h"
+#include "printing/backend/cups_printer.h"
+#include "printing/backend/print_backend_consts.h"
+#include "printing/units.h"
+
+namespace printing {
+
+namespace {
+
+const char kIppCollate[] = "sheet-collate";  // RFC 3381
+const char kIppCopies[] = CUPS_COPIES;
+const char kIppColor[] = CUPS_PRINT_COLOR_MODE;
+const char kIppMedia[] = CUPS_MEDIA;
+const char kIppDuplex[] = CUPS_SIDES;
+
+const char kCollated[] = "collated";
+
+const int kMicronsPerMM = 1000;
+const double kMMPerInch = 25.4;
+const double kMicronsPerInch = kMMPerInch * kMicronsPerMM;
+
+enum Unit {
+  INCHES,
+  MILLIMETERS,
+};
+
+const std::map<const base::StringPiece, ColorModel> kColorMap{

[Lei Zhang, 2016/07/19 22:26:39]

Can't do this. It adds a static initializer. Given the size of |kColorMap|, just
make this a C array and iterate through it. Remove the <map> include too.

const struct ColorList {
  const char* color;
  ColorModel model;
} kColorList[] = {
  { ... },
  ...
};

[skau, 2016/07/20 23:58:22]

Thanks.  That works well.

+    {CUPS_PRINT_COLOR_MODE_COLOR, COLORMODE_COLOR},
+    {CUPS_PRINT_COLOR_MODE_MONOCHROME, COLORMODE_MONOCHROME},
+};
+
+ColorModel ColorModelFromIppColor(base::StringPiece ippColor) {
+  auto found = kColorMap.find(ippColor);
+  return found == kColorMap.end() ? UNKNOWN_COLOR_MODEL : found->second;
+}
+
+bool PrinterSupportsValue(const CupsPrinter& printer,
+                          base::StringPiece name,
+                          base::StringPiece value) {
+  std::vector<base::StringPiece> values =
+      printer.GetSupportedOptionValueStrings(name);
+  auto iter = std::find(values.begin(), values.end(), value);
+  return iter != values.end();
+}
+
+DuplexMode PrinterDefaultDuplex(const CupsPrinter& printer) {
+  ipp_attribute_t* attr = printer.GetDefaultOptionValue(kIppDuplex);
+  if (!attr)
+    return UNKNOWN_DUPLEX_MODE;
+
+  const char* value = ippGetString(attr, 0, nullptr);
+  if (base::EqualsCaseInsensitiveASCII(value, CUPS_SIDES_ONE_SIDED))
+    return SIMPLEX;
+  if (base::EqualsCaseInsensitiveASCII(value, CUPS_SIDES_TWO_SIDED_PORTRAIT))
+    return LONG_EDGE;
+  if (base::EqualsCaseInsensitiveASCII(value, CUPS_SIDES_TWO_SIDED_LANDSCAPE))
+    return SHORT_EDGE;
+
+  return UNKNOWN_DUPLEX_MODE;
+}
+
+gfx::Size DimensionsToMicrons(base::StringPiece value) {
+  Unit unit;
+  base::StringPiece dims;
+  size_t unit_position;
+  if ((unit_position = value.find("mm")) != base::StringPiece::npos) {
+    unit = MILLIMETERS;
+    dims = value.substr(0, unit_position);
+  } else if ((unit_position = value.find("in")) != base::StringPiece::npos) {
+    unit = INCHES;
+    dims = value.substr(0, unit_position);
+  } else {
+    LOG(WARNING) << "Could not parse paper dimensions";
+    return {0, 0};
+  }
+
+  std::vector<std::string> pieces = base::SplitString(
+      dims, "x", base::TRIM_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
+  double width;
+  double height;
+
+  if (pieces.size() != 2 || !base::StringToDouble(pieces[0], &width) ||
+      !base::StringToDouble(pieces[1], &height)) {
+    return {0, 0};
+  }
+
+  int width_microns;
+  int height_microns;
+
+  switch (unit) {
+    case MILLIMETERS:
+      width_microns = width * kMicronsPerMM;
+      height_microns = height * kMicronsPerMM;
+      break;
+    case INCHES:
+      width_microns = width * kMicronsPerInch;
+      height_microns = height * kMicronsPerInch;
+      break;
+    default:
+      NOTREACHED();
+      break;
+  }
+
+  return gfx::Size{width_microns, height_microns};
+}
+
+PrinterSemanticCapsAndDefaults::Paper ParsePaper(base::StringPiece value) {
+  // <name>_<width>x<height>{in,mm}
+  // e.g. na_letter_8.5x11in, iso_a4_210x297mm
+
+  std::vector<base::StringPiece> pieces = base::SplitStringPiece(
+      value, "_", base::TRIM_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
+  if (pieces.size() < 2) {
+    // we expect at least a display string and a dimension string
+    return PrinterSemanticCapsAndDefaults::Paper();
+  }
+
+  base::StringPiece dimensions = pieces.back();
+
+  std::string display = pieces[0].as_string();
+  for (size_t i = 1; i <= pieces.size() - 2; ++i) {
+    display.append(" ");
+    pieces[i].AppendToString(&display);
+  }
+
+  PrinterSemanticCapsAndDefaults::Paper paper;
+  paper.display_name = display;
+  paper.vendor_id = value.as_string();
+  paper.size_um = DimensionsToMicrons(dimensions);
+
+  return paper;
+}
+
+void ExtractColor(const CupsPrinter& printer,
+                  PrinterSemanticCapsAndDefaults* printer_info) {
+  printer_info->bw_model = UNKNOWN_COLOR_MODEL;
+  printer_info->color_model = UNKNOWN_COLOR_MODEL;
+
+  // color and b&w
+  std::vector<ColorModel> color_models = SupportedColorModels(printer);
+  for (ColorModel color : color_models) {
+    switch (color) {
+      case COLORMODE_COLOR:
+        printer_info->color_model = COLORMODE_COLOR;
+        break;
+      case COLORMODE_MONOCHROME:
+        printer_info->bw_model = COLORMODE_MONOCHROME;
+        break;
+      default:
+        // value not needed
+        break;
+    }
+  }
+
+  // changeable
+  printer_info->color_changeable =
+      (printer_info->color_model != UNKNOWN_COLOR_MODEL &&
+       printer_info->bw_model != UNKNOWN_COLOR_MODEL);
+
+  // default color
+  printer_info->color_default = DefaultColorModel(printer);
+}
+
+void ExtractCopies(const CupsPrinter& printer,
+                   PrinterSemanticCapsAndDefaults* printer_info) {
+  // copies
+  int upper_bound;
+  int lower_bound;
+  CopiesRange(printer, &lower_bound, &upper_bound);
+  printer_info->copies_capable = (lower_bound != -1) && (upper_bound >= 2);
+}
+
+}  // anonymous namespace

[Lei Zhang, 2016/07/19 22:26:39]

no "anonymous "

[skau, 2016/07/20 23:58:22]

Done.

+
+ColorModel DefaultColorModel(const CupsPrinter& printer) {
+  // default color
+  ipp_attribute_t* attr = printer.GetDefaultOptionValue(kIppColor);
+  if (!attr)
+    return UNKNOWN_COLOR_MODEL;
+
+  const char* value = ippGetString(attr, 0, nullptr);

[Lei Zhang, 2016/07/19 22:26:39]

Just combine with the next line and drop |value|. Ditto in a few places below.

[skau, 2016/07/20 23:58:23]

Done.

+  return ColorModelFromIppColor(value);
+}
+
+std::vector<ColorModel> SupportedColorModels(const CupsPrinter& printer) {
+  std::vector<ColorModel> colors;
+
+  std::vector<base::StringPiece> color_modes =
+      printer.GetSupportedOptionValueStrings(kIppColor);
+
+  for (base::StringPiece color : color_modes) {
+    ColorModel color_model = ColorModelFromIppColor(color);
+    if (color_model != UNKNOWN_COLOR_MODEL) {
+      colors.push_back(color_model);
+    }
+  }
+
+  return colors;
+}
+
+PrinterSemanticCapsAndDefaults::Paper DefaultPaper(const CupsPrinter& printer) {
+  ipp_attribute_t* attr = printer.GetDefaultOptionValue(kIppMedia);
+  if (!attr)
+    return PrinterSemanticCapsAndDefaults::Paper();
+
+  const char* value = ippGetString(attr, 0, nullptr);
+  return ParsePaper(value);
+}
+
+std::vector<PrinterSemanticCapsAndDefaults::Paper> SupportedPapers(
+    const CupsPrinter& printer) {
+  std::vector<base::StringPiece> papers =
+      printer.GetSupportedOptionValueStrings(kIppMedia);
+  std::vector<PrinterSemanticCapsAndDefaults::Paper> parsed_papers;
+  for (base::StringPiece paper : papers) {
+    PrinterSemanticCapsAndDefaults::Paper p = ParsePaper(paper);

[Lei Zhang, 2016/07/19 22:26:39]

Also less wordy if it's just combined with the next line.

[skau, 2016/07/20 23:58:23]

Done.

+    parsed_papers.push_back(p);
+  }
+
+  return parsed_papers;
+}
+
+void CopiesRange(const CupsPrinter& printer,
+                 int* lower_bound,
+                 int* upper_bound) {
+  ipp_attribute_t* attr = printer.GetSupportedOptionValues(kIppCopies);
+  if (attr) {

[Lei Zhang, 2016/07/19 22:26:39]

If |attr| is nullptr, what happens? Does |lower_bound| and |upper_bound| get
initialized properly? In the previous patch set, this code just set
|copies_capable| to false directly if |attr| was nullptr.

[skau, 2016/07/20 23:58:22]

Whoops.  I'll write some unit tests.

+    *lower_bound = -1;
+    *upper_bound = -1;
+  }
+
+  *lower_bound = ippGetRange(attr, 0, upper_bound);
+}
+
+bool CollateCapable(const CupsPrinter& printer) {
+  std::vector<base::StringPiece> values =
+      printer.GetSupportedOptionValueStrings(kIppCollate);
+  auto iter = std::find(values.begin(), values.end(), kCollated);

[Lei Zhang, 2016/07/19 22:26:39]

Just: return ContainsValue(values, kCollated);

Same for PrinterSupportsValue() above. ContainsValue is in base/stl_util.h.

[skau, 2016/07/20 23:58:22]

Thanks.  I didn't know we had that.

+  return iter != values.end();
+}
+
+bool CollateDefault(const CupsPrinter& printer) {
+  ipp_attribute_t* attr = printer.GetDefaultOptionValue(kIppCollate);
+  if (!attr)
+    return false;
+
+  base::StringPiece name = ippGetString(attr, 0, nullptr);
+  return name.compare(kCollated) == 0;
+}
+
+void CapsAndDefaultsFromPrinter(const CupsPrinter& printer,
+                                PrinterSemanticCapsAndDefaults* printer_info) {
+  // duplex
+  printer_info->duplex_default = PrinterDefaultDuplex(printer);
+  printer_info->duplex_capable =
+      PrinterSupportsValue(printer, kIppDuplex, CUPS_SIDES_TWO_SIDED_PORTRAIT);
+
+  // collate
+  printer_info->collate_default = CollateDefault(printer);
+  printer_info->collate_capable = CollateCapable(printer);
+
+  // paper
+  printer_info->default_paper = DefaultPaper(printer);
+  printer_info->papers = SupportedPapers(printer);
+
+  ExtractCopies(printer, printer_info);
+  ExtractColor(printer, printer_info);
+
+  // TODO(skau): Add dpi and default_dpi
+}
+
+}  //  namespace printing