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Implement IPP Get-Jobs and Get-Printer-Attributes requests.
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CUPS provides cupsGetJobs2 but it doesn't provide the necessary fields
to report status accurately.  Notably, it doesn't provide
job-impressions-completed or printer-state-reasons both of which are
necessary to differentiate errors.

BUG=684853

Review-Url: https://codereview.chromium.org/2691093006
Cr-Commit-Position: refs/heads/master@{#456225}
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skau authored and Commit bot committed Mar 11, 2017
1 parent dece487 commit a26877d
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Showing 8 changed files with 680 additions and 96 deletions.
89 changes: 68 additions & 21 deletions chrome/browser/chromeos/printing/cups_print_job_manager_impl.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,9 @@ namespace {
// The rate in milliseconds at which we will poll CUPS for print job updates.
const int kPollRate = 1000;

// Threshold for giving up on communicating with CUPS.
const int kRetryMax = 6;

// Returns the equivalient CupsPrintJob#State from a CupsJob#JobState.
chromeos::CupsPrintJob::State ConvertState(printing::CupsJob::JobState state) {
using cpj = chromeos::CupsPrintJob::State;
Expand Down Expand Up @@ -61,6 +64,13 @@ chromeos::CupsPrintJob::State ConvertState(printing::CupsJob::JobState state) {
return cpj::STATE_NONE;
}

chromeos::QueryResult QueryCups(::printing::CupsConnection* connection,
const std::vector<std::string>& printer_ids) {
chromeos::QueryResult result;
result.success = connection->GetJobs(printer_ids, &result.queues);
return result;
}

} // namespace

namespace chromeos {
Expand Down Expand Up @@ -134,6 +144,7 @@ bool CupsPrintJobManagerImpl::CreatePrintJob(const std::string& printer_name,
total_page_number);
std::string key = cpj->GetUniqueId();
jobs_[key] = std::move(cpj);

CupsPrintJob* job = jobs_[key].get();
NotifyJobCreated(job);

Expand All @@ -153,36 +164,67 @@ void CupsPrintJobManagerImpl::ScheduleQuery() {
void CupsPrintJobManagerImpl::ScheduleQuery(const base::TimeDelta& delay) {
if (!in_query_) {
in_query_ = true;
content::BrowserThread::PostDelayedTask(
content::BrowserThread::FILE_USER_BLOCKING, FROM_HERE,
base::Bind(&CupsPrintJobManagerImpl::QueryCups,

base::SequencedTaskRunnerHandle::Get()->PostDelayedTask(
FROM_HERE,
base::Bind(&CupsPrintJobManagerImpl::PostQuery,
weak_ptr_factory_.GetWeakPtr()),
base::TimeDelta::FromMilliseconds(kPollRate));
delay);
}
}

// Query CUPS asynchronously. Post results back to UI thread.
void CupsPrintJobManagerImpl::QueryCups() {
std::vector<::printing::CupsJob> jobs = cups_connection_.GetJobs();
void CupsPrintJobManagerImpl::PostQuery() {
// The set of active printers is expected to be small.
std::set<std::string> printer_ids;
for (const auto& entry : jobs_) {
printer_ids.insert(entry.second->printer().id());
}
std::vector<std::string> ids{printer_ids.begin(), printer_ids.end()};

content::BrowserThread::PostTask(
content::BrowserThread::ID::UI, FROM_HERE,
content::BrowserThread::PostTaskAndReplyWithResult(
content::BrowserThread::FILE_USER_BLOCKING, FROM_HERE,
base::Bind(&QueryCups, &cups_connection_, ids),
base::Bind(&CupsPrintJobManagerImpl::UpdateJobs,
weak_ptr_factory_.GetWeakPtr(), jobs));
weak_ptr_factory_.GetWeakPtr()));
}

// Use job information to update local job states. Previously completed jobs
// could be in |jobs| but those are ignored as we will not emit updates for them
// after they are completed.
void CupsPrintJobManagerImpl::UpdateJobs(
const std::vector<::printing::CupsJob>& jobs) {
void CupsPrintJobManagerImpl::UpdateJobs(const QueryResult& result) {
const std::vector<::printing::QueueStatus>& queues = result.queues;

// Query has completed. Allow more queries.
in_query_ = false;

// If the query failed, either retry or purge.
if (!result.success) {
retry_count_++;
LOG(WARNING) << "Failed to query CUPS for queue status. Schedule retry ("
<< retry_count_ << ")";
if (retry_count_ > kRetryMax) {
LOG(ERROR) << "CUPS is unreachable. Giving up on all jobs.";
PurgeJobs();
} else {
// Schedule another query with a larger delay.
DCHECK_GE(1, retry_count_);
ScheduleQuery(
base::TimeDelta::FromMilliseconds(kPollRate * retry_count_));
}
return;
}

// A query has completed. Reset retry counter.
retry_count_ = 0;

std::vector<std::string> active_jobs;
for (auto& job : jobs) {
std::string key = CupsPrintJob::GetUniqueId(job.printer_id, job.id);
const auto& entry = jobs_.find(key);
if (entry != jobs_.end()) {
for (const auto& queue : queues) {
for (auto& job : queue.jobs) {
std::string key = CupsPrintJob::GetUniqueId(job.printer_id, job.id);
const auto& entry = jobs_.find(key);
if (entry == jobs_.end())
continue;

CupsPrintJob* print_job = entry->second.get();

// Update a job we're tracking.
Expand All @@ -199,18 +241,23 @@ void CupsPrintJobManagerImpl::UpdateJobs(

// Keep polling until all jobs complete or error.
if (!active_jobs.empty()) {
// During normal operations, we poll at the default rate.
ScheduleQuery();
} else if (!jobs_.empty()) {
// We're tracking jobs that we didn't receive an update for. Something bad
// has happened.
LOG(ERROR) << "Lost track of (" << jobs_.size() << ") jobs";
for (const auto& entry : jobs_) {
// Declare all lost jobs errors.
JobStateUpdated(entry.second.get(), CupsPrintJob::State::STATE_ERROR);
}
PurgeJobs();
}
}

jobs_.clear();
void CupsPrintJobManagerImpl::PurgeJobs() {
for (const auto& entry : jobs_) {
// Declare all lost jobs errors.
JobStateUpdated(entry.second.get(), CupsPrintJob::State::STATE_ERROR);
}

jobs_.clear();
}

void CupsPrintJobManagerImpl::JobStateUpdated(CupsPrintJob* job,
Expand Down
18 changes: 15 additions & 3 deletions chrome/browser/chromeos/printing/cups_print_job_manager_impl.h
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,11 @@ class Profile;

namespace chromeos {

struct QueryResult {
bool success;
std::vector<::printing::QueueStatus> queues;
};

class CupsPrintJobManagerImpl : public CupsPrintJobManager,
public content::NotificationObserver {
public:
Expand Down Expand Up @@ -52,11 +57,15 @@ class CupsPrintJobManagerImpl : public CupsPrintJobManager,
// Schedule a query of CUPS for print job status with a delay of |delay|.
void ScheduleQuery(const base::TimeDelta& delay);

// Query CUPS for print job status.
void QueryCups();
// Schedule the CUPS query off the UI thread. Posts results back to UI thread
// to UpdateJobs.
void PostQuery();

// Process jobs from CUPS and perform notifications.
void UpdateJobs(const std::vector<::printing::CupsJob>& jobs);
void UpdateJobs(const QueryResult& results);

// Mark remaining jobs as errors and remove active jobs.
void PurgeJobs();

// Updates the state and performs the appropriate notifications.
void JobStateUpdated(CupsPrintJob* job, CupsPrintJob::State new_state);
Expand All @@ -67,6 +76,9 @@ class CupsPrintJobManagerImpl : public CupsPrintJobManager,
// Prevents multiple queries from being scheduled simultaneously.
bool in_query_ = false;

// Records the number of consecutive times the GetJobs query has failed.
int retry_count_ = 0;

::printing::CupsConnection cups_connection_;
content::NotificationRegistrar registrar_;
base::WeakPtrFactory<CupsPrintJobManagerImpl> weak_ptr_factory_;
Expand Down
2 changes: 2 additions & 0 deletions printing/BUILD.gn
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Original file line number Diff line number Diff line change
Expand Up @@ -189,6 +189,8 @@ component("printing") {
"backend/cups_deleters.h",
"backend/cups_ipp_util.cc",
"backend/cups_ipp_util.h",
"backend/cups_jobs.cc",
"backend/cups_jobs.h",
"backend/cups_printer.cc",
"backend/cups_printer.h",
"backend/print_backend_cups_ipp.cc",
Expand Down
100 changes: 47 additions & 53 deletions printing/backend/cups_connection.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -4,18 +4,31 @@

#include "printing/backend/cups_connection.h"

#include <map>
#include <set>
#include <string>
#include <utility>

#include "base/logging.h"
#include "base/memory/ptr_util.h"
#include "base/strings/stringprintf.h"
#include "printing/backend/cups_jobs.h"

namespace printing {

namespace {

const int kTimeoutMs = 3000;
constexpr int kTimeoutMs = 3000;

// The number of jobs we'll retrieve for a queue. We expect a user to queue at
// most 10 jobs per printer. If they queue more, they won't receive updates for
// the 11th job until one finishes.
constexpr int kProcessingJobsLimit = 10;

// The number of completed jobs that are retrieved. We only need one update for
// a completed job to confirm its final status. We could retrieve one but we
// retrieve the last 3 in case that many finished between queries.
constexpr int kCompletedJobsLimit = 3;

class DestinationEnumerator {
public:
Expand Down Expand Up @@ -44,42 +57,6 @@ class DestinationEnumerator {
DISALLOW_COPY_AND_ASSIGN(DestinationEnumerator);
};

CupsJob createCupsJob(int job_id,
base::StringPiece job_title,
base::StringPiece printer_id,
ipp_jstate_t state) {
CupsJob::JobState converted_state = CupsJob::UNKNOWN;
switch (state) {
case IPP_JOB_ABORTED:
converted_state = CupsJob::ABORTED;
break;
case IPP_JOB_CANCELLED:
converted_state = CupsJob::CANCELED;
break;
case IPP_JOB_COMPLETED:
converted_state = CupsJob::COMPLETED;
break;
case IPP_JOB_HELD:
converted_state = CupsJob::HELD;
break;
case IPP_JOB_PENDING:
converted_state = CupsJob::PENDING;
break;
case IPP_JOB_PROCESSING:
converted_state = CupsJob::PROCESSING;
break;
case IPP_JOB_STOPPED:
converted_state = CupsJob::STOPPED;
break;
default:
NOTREACHED();
break;
}

return {job_id, job_title.as_string(), printer_id.as_string(),
converted_state};
}

} // namespace

CupsConnection::CupsConnection(const GURL& print_server_url,
Expand Down Expand Up @@ -162,24 +139,41 @@ std::unique_ptr<CupsPrinter> CupsConnection::GetPrinter(
std::unique_ptr<cups_dinfo_t, DestInfoDeleter>(info));
}

std::vector<CupsJob> CupsConnection::GetJobs() {
cups_job_t* jobs;
int num_jobs = cupsGetJobs2(cups_http_.get(), // http connection
&jobs, // out param
nullptr, // all printers
0, // all users
CUPS_WHICHJOBS_ALL);

const JobsDeleter deleter(num_jobs);
std::unique_ptr<cups_job_t, const JobsDeleter&> scoped_jobs(jobs, deleter);

std::vector<CupsJob> job_copies;
for (int i = 0; i < num_jobs; i++) {
job_copies.push_back(
createCupsJob(jobs[i].id, jobs[i].title, jobs[i].dest, jobs[i].state));
bool CupsConnection::GetJobs(const std::vector<std::string>& printer_ids,
std::vector<QueueStatus>* queues) {
DCHECK(queues);
if (!Connect()) {
LOG(ERROR) << "Could not establish connection to CUPS";
return false;
}

std::vector<QueueStatus> temp_queues;

for (const std::string& id : printer_ids) {
temp_queues.emplace_back();
QueueStatus* queue_status = &temp_queues.back();

if (!GetPrinterStatus(cups_http_.get(), id,
&queue_status->printer_status)) {
LOG(WARNING) << "Could not retrieve printer status for " << id;
return false;
}

if (!GetCupsJobs(cups_http_.get(), id, kCompletedJobsLimit, COMPLETED,
&queue_status->jobs)) {
LOG(WARNING) << "Could not get completed jobs for " << id;
return false;
}

if (!GetCupsJobs(cups_http_.get(), id, kProcessingJobsLimit, PROCESSING,
&queue_status->jobs)) {
LOG(WARNING) << "Could not get in progress jobs for " << id;
return false;
}
}
queues->insert(queues->end(), temp_queues.begin(), temp_queues.end());

return job_copies;
return true;
}

std::string CupsConnection::server_name() const {
Expand Down
30 changes: 11 additions & 19 deletions printing/backend/cups_connection.h
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Original file line number Diff line number Diff line change
Expand Up @@ -14,29 +14,17 @@
#include "base/macros.h"
#include "base/memory/weak_ptr.h"
#include "printing/backend/cups_deleters.h"
#include "printing/backend/cups_jobs.h"
#include "printing/backend/cups_printer.h"
#include "printing/printing_export.h"
#include "url/gurl.h"

namespace printing {

// Represents a print job sent to the queue.
struct PRINTING_EXPORT CupsJob {
enum JobState {
UNKNOWN,
PENDING,
HELD,
COMPLETED,
PROCESSING,
STOPPED,
CANCELED,
ABORTED
};

int id;
std::string title;
std::string printer_id;
JobState state;
// Represents the status of a printer queue.
struct PRINTING_EXPORT QueueStatus {
PrinterStatus printer_status;
std::vector<CupsJob> jobs;
};

// Represents a connection to a CUPS server.
Expand All @@ -56,8 +44,12 @@ class PRINTING_EXPORT CupsConnection {
// Returns a printer for |printer_name| from the connected server.
std::unique_ptr<CupsPrinter> GetPrinter(const std::string& printer_name);

// Returns a list of print jobs from all connected printers.
std::vector<CupsJob> GetJobs();
// Queries CUPS for printer queue status for |printer_ids|. Populates |jobs|
// with said information with one QueueStatus per printer_id. Returns true if
// all the queries were successful. In the event of failure, |jobs| will be
// unchanged.
bool GetJobs(const std::vector<std::string>& printer_ids,
std::vector<QueueStatus>* jobs);

std::string server_name() const;

Expand Down
2 changes: 2 additions & 0 deletions printing/backend/cups_ipp_util.h
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,8 @@
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Methods for parsing IPP Printer attributes.

#ifndef PRINTING_BACKEND_CUPS_IPP_UTIL_H_
#define PRINTING_BACKEND_CUPS_IPP_UTIL_H_

Expand Down
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