Add a method to query IPP printers for attributes.

chrome/browser/chromeos/printing/printer_info_cups.cc

+// Copyright 2017 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 "chrome/browser/chromeos/printing/printer_info.h"
+
+#include <algorithm>
+#include <array>
+#include <string>
+
+#include "base/logging.h"
+#include "base/memory/ptr_util.h"
+#include "base/strings/string_piece.h"
+#include "base/strings/string_util.h"
+#include "base/task_runner_util.h"
+#include "base/task_scheduler/post_task.h"
+#include "base/task_scheduler/task_traits.h"
+#include "base/version.h"
+#include "printing/backend/cups_jobs.h"
+
+namespace {
+
+const char kPdfMimeType[] = "application/pdf";
+const char kPwgRasterMimeType[] = "image/pwg-raster";
+
+// List of known multi-word printer manufacturers to help with make-and-model
+// string parsing.  Keep in UPPER CASE as that's how matches are performed.
+const std::array<base::StringPiece, 4> kMultiWordManufacturers{

[Lei Zhang, 2017/06/03 01:17:14]

Oh, you can't use StringPiece here. That creates static initializers. Stick with
const char*.

[skau, 2017/06/05 19:51:04]

Done.

+    {"FUJI XEROX", "KODAK FUNAI", "KONICA MINOLTA", "TEXAS INSTRUMENTS"}};
+
+// Returns the length of the portion of |make_and_model| representing the
+// manufacturer.  This is either a value from kMultiWordManufacaturers or the
+// first token.  If there is only one token or less, we assume that it does not
+// represent the manufacturer and return 0.
+size_t ManufacturerLength(base::StringPiece make_and_model) {
+  // TODO(crbug.com/729245): Update when better data is available.
+  for (const base::StringPiece& multi_word_manufacturer :
+       kMultiWordManufacturers) {
+    if (base::StartsWith(make_and_model, multi_word_manufacturer,
+                         base::CompareCase::INSENSITIVE_ASCII)) {
+      return multi_word_manufacturer.size();
+    }
+  }
+
+  // The position of the first space is equal to the length of the first token.
+  size_t first_space = make_and_model.find(" ");
+  return first_space != base::StringPiece::npos ? first_space : 0;
+}
+
+// Returns true if any of the |ipp_versions| are greater than or equal to 2.0.
+bool AllowedIpp(const std::vector<base::Version>& ipp_versions) {
+  auto found = std::find_if(ipp_versions.begin(), ipp_versions.end(),
+                            [](const base::Version& version) {
+                              // Check that the major version is at least 2.
+                              DCHECK(version.IsValid());

[Lei Zhang, 2017/06/03 00:53:14]

How about making this a real check?

return version.IsValid() && version.components()[0] >= 2;

Because if the DCHECK fails, you are going to crash.

[skau, 2017/06/05 19:51:03]

Done.

+                              return version.components()[0] >= 2;
+                            });
+
+  return found != ipp_versions.end();
+}
+
+// Returns true if |mime_type| is one of the supported types.
+bool SupportedMime(const std::string& mime_type) {
+  return mime_type == kPwgRasterMimeType || mime_type == kPdfMimeType;
+}
+
+// Returns true if |formats| contains one of the supported printer description
+// languages for an autoconf printer identified by MIME type.
+bool SupportsRequiredPDLS(const std::vector<std::string>& formats) {
+  auto found = std::find_if(formats.begin(), formats.end(), &SupportedMime);
+  return found != formats.end();
+}
+
+// Returns true if |info| describes a printer for which we want to attempt
+// automatic configuration.
+bool IsAutoconf(const ::printing::PrinterInfo& info) {
+  return info.ipp_everywhere || (AllowedIpp(info.ipp_versions) &&
+                                 SupportsRequiredPDLS(info.document_formats));
+}
+
+// Dispatches an IPP request to |host| to retrieve printer information.  Returns
+// a nullptr if the request fails.
+std::unique_ptr<::printing::PrinterInfo> QueryPrinterImpl(
+    const std::string& host,
+    const int port,
+    const std::string& path) {
+  auto info = base::MakeUnique<::printing::PrinterInfo>();
+  if (!::printing::GetPrinterInfo(host, port, path, info.get())) {
+    LOG(ERROR) << "Could not retrieve printer info";
+    return nullptr;
+  }
+
+  return info;
+}
+
+// Handles the request for |info|.  Parses make and model information before
+// calling |callback|.
+void OnPrinterQueried(const chromeos::PrinterInfoCallback& callback,
+                      std::unique_ptr<::printing::PrinterInfo> info) {
+  if (!info) {
+    VLOG(1) << "Could not reach printer";
+    callback.Run(false, std::string(), std::string(), false);
+    return;
+  }
+
+  // TODO(skau): Handle manufacturers with two word names.

[Lei Zhang, 2017/06/03 00:53:14]

Mostly obsolete now?

[skau, 2017/06/05 19:51:04]

Done.

+  base::StringPiece make_and_model(info->make_and_model);
+  base::StringPiece make;
+  base::StringPiece model;
+
+  size_t split = ManufacturerLength(make_and_model);
+  if (split != 0) {
+    make = make_and_model.substr(0, split);
+    model = make_and_model.substr(split + 1);
+  } else {
+    // If there's only one word or an empty string, use it.

[Lei Zhang, 2017/06/03 00:53:14]

Do you have a collection of PPDs to test with to see if this ever happens? I was
also thinking what if the make is missing, but the model is multi-word?

Since this is data coming from CUPS, and OS X uses CUPS - how does Apple deal
with this?

[skau, 2017/06/05 19:51:03]

This isn't an expected condition.  Per the IPP spec, the string we're querying
should be composed of at least two tokens. However, it's possible we're talking
to a device that implements the spec incorrectly and this is the safest way for
us to handle that.

[Lei Zhang, 2017/06/06 22:02:37]

If it's against the spec, would it be reasonable to just fail?

[skau, 2017/06/07 22:23:36]

I'd rather not rely on the printer implementing the IPP spec correctly.  And
technically, there's nothing that specifies that a space should appear in this
field.

4.4.8 printer-make-and-model (text(127))

   This Printer attribute identifies the make and model of the device.
   The device manufacturer may initially populate this attribute.

At any rate, we've decided that we're going to eliminate the 'make' field since
this parsing is causing a lot of trouble for limited benefit.  This is the bug
I've filed crbug.com/730242.  However, I'm going to keep this in this CL because
the data in user prefs will need to be migrated before we can eliminate it.

+    model = make_and_model;
+  }
+
+  callback.Run(true, make.as_string(), model.as_string(), IsAutoconf(*info));
+}
+
+}  // namespace
+
+namespace chromeos {
+
+void QueryIppPrinter(const std::string& host,
+                     const int port,
+                     const std::string& path,
+                     const PrinterInfoCallback& callback) {
+  DCHECK(!host.empty());
+
+  // QueryPrinterImpl could block on a network call for a noticable amount of
+  // time (100s of ms). Also the user is waiting on this result.  Thus, run at
+  // USER_VISIBLE with MayBlock.
+  base::PostTaskWithTraitsAndReplyWithResult(
+      FROM_HERE,
+      base::TaskTraits(base::TaskPriority::USER_VISIBLE, base::MayBlock()),
+      base::Bind(&QueryPrinterImpl, host, port, path),
+      base::Bind(&OnPrinterQueried, callback));
+}
+
+}  // namespace chromeos