root/chrome/browser/printing/print_job_worker.cc

DEFINITIONS

1. HoldRefCallback
2. NotificationCallback
3. weak_factory_
4. SetNewOwner
5. SetPrintDestination
6. GetSettings
7. SetSettings
8. UpdatePrintSettings
9. GetSettingsDone
10. GetSettingsWithUI
11. GetSettingsWithUIDone
12. UseDefaultSettings
13. StartPrinting
14. OnDocumentChanged
15. OnNewPage
16. Cancel
17. OnDocumentDone
18. SpoolPage
19. OnFailure

// Copyright (c) 2012 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/printing/print_job_worker.h"

#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/callback.h"
#include "base/compiler_specific.h"
#include "base/message_loop/message_loop.h"
#include "base/values.h"
#include "chrome/browser/browser_process.h"
#include "chrome/browser/chrome_notification_types.h"
#include "chrome/browser/printing/print_job.h"
#include "chrome/browser/printing/printing_ui_web_contents_observer.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/notification_service.h"
#include "grit/generated_resources.h"
#include "printing/print_job_constants.h"
#include "printing/printed_document.h"
#include "printing/printed_page.h"
#include "printing/printing_utils.h"
#include "ui/base/l10n/l10n_util.h"

using content::BrowserThread;

namespace {

// Helper function to ensure |owner| is valid until at least |callback| returns.
void HoldRefCallback(const scoped_refptr<printing::PrintJobWorkerOwner>& owner,
                     const base::Closure& callback) {
  callback.Run();
}

}  // namespace

namespace printing {

void NotificationCallback(PrintJobWorkerOwner* print_job,
                          JobEventDetails::Type detail_type,
                          PrintedDocument* document,
                          PrintedPage* page) {
  JobEventDetails* details = new JobEventDetails(detail_type, document, page);
  content::NotificationService::current()->Notify(
      chrome::NOTIFICATION_PRINT_JOB_EVENT,
      // We know that is is a PrintJob object in this circumstance.
      content::Source<PrintJob>(static_cast<PrintJob*>(print_job)),
      content::Details<JobEventDetails>(details));
}

PrintJobWorker::PrintJobWorker(PrintJobWorkerOwner* owner)
    : Thread("Printing_Worker"),
      owner_(owner),
      weak_factory_(this) {
  // The object is created in the IO thread.
  DCHECK_EQ(owner_->message_loop(), base::MessageLoop::current());

  printing_context_.reset(PrintingContext::Create(
      g_browser_process->GetApplicationLocale()));
}

PrintJobWorker::~PrintJobWorker() {
  // The object is normally deleted in the UI thread, but when the user
  // cancels printing or in the case of print preview, the worker is destroyed
  // on the I/O thread.
  DCHECK_EQ(owner_->message_loop(), base::MessageLoop::current());
  Stop();
}

void PrintJobWorker::SetNewOwner(PrintJobWorkerOwner* new_owner) {
  DCHECK(page_number_ == PageNumber::npos());
  owner_ = new_owner;
}

void PrintJobWorker::SetPrintDestination(
    PrintDestinationInterface* destination) {
  destination_ = destination;
}

void PrintJobWorker::GetSettings(
    bool ask_user_for_settings,
    scoped_ptr<PrintingUIWebContentsObserver> web_contents_observer,
    int document_page_count,
    bool has_selection,
    MarginType margin_type) {
  DCHECK_EQ(message_loop(), base::MessageLoop::current());
  DCHECK_EQ(page_number_, PageNumber::npos());

  // Recursive task processing is needed for the dialog in case it needs to be
  // destroyed by a task.
  // TODO(thestig): This code is wrong. SetNestableTasksAllowed(true) is needed
  // on the thread where the PrintDlgEx is called, and definitely both calls
  // should happen on the same thread. See http://crbug.com/73466
  // MessageLoop::current()->SetNestableTasksAllowed(true);
  printing_context_->set_margin_type(margin_type);

  // When we delegate to a destination, we don't ask the user for settings.
  // TODO(mad): Ask the destination for settings.
  if (ask_user_for_settings && destination_.get() == NULL) {
    BrowserThread::PostTask(
        BrowserThread::UI, FROM_HERE,
        base::Bind(&HoldRefCallback, make_scoped_refptr(owner_),
                   base::Bind(&PrintJobWorker::GetSettingsWithUI,
                              base::Unretained(this),
                              base::Passed(&web_contents_observer),
                              document_page_count,
                              has_selection)));
  } else {
    BrowserThread::PostTask(
        BrowserThread::UI, FROM_HERE,
        base::Bind(&HoldRefCallback, make_scoped_refptr(owner_),
                   base::Bind(&PrintJobWorker::UseDefaultSettings,
                              base::Unretained(this))));
  }
}

void PrintJobWorker::SetSettings(
    const base::DictionaryValue* const new_settings) {
  DCHECK_EQ(message_loop(), base::MessageLoop::current());

  BrowserThread::PostTask(
      BrowserThread::UI, FROM_HERE,
      base::Bind(&HoldRefCallback, make_scoped_refptr(owner_),
                 base::Bind(&PrintJobWorker::UpdatePrintSettings,
                            base::Unretained(this), new_settings)));
}

void PrintJobWorker::UpdatePrintSettings(
    const base::DictionaryValue* const new_settings) {
  // Create new PageRanges based on |new_settings|.
  PageRanges new_ranges;
  const base::ListValue* page_range_array;
  if (new_settings->GetList(kSettingPageRange, &page_range_array)) {
    for (size_t index = 0; index < page_range_array->GetSize(); ++index) {
      const base::DictionaryValue* dict;
      if (!page_range_array->GetDictionary(index, &dict))
        continue;

      PageRange range;
      if (!dict->GetInteger(kSettingPageRangeFrom, &range.from) ||
          !dict->GetInteger(kSettingPageRangeTo, &range.to)) {
        continue;
      }

      // Page numbers are 1-based in the dictionary.
      // Page numbers are 0-based for the printing context.
      range.from--;
      range.to--;
      new_ranges.push_back(range);
    }
  }
  PrintingContext::Result result =
      printing_context_->UpdatePrintSettings(*new_settings, new_ranges);
  delete new_settings;
  GetSettingsDone(result);
}

void PrintJobWorker::GetSettingsDone(PrintingContext::Result result) {
  // Most PrintingContext functions may start a message loop and process
  // message recursively, so disable recursive task processing.
  // TODO(thestig): See above comment. SetNestableTasksAllowed(false) needs to
  // be called on the same thread as the previous call.  See
  // http://crbug.com/73466
  // MessageLoop::current()->SetNestableTasksAllowed(false);

  // We can't use OnFailure() here since owner_ may not support notifications.

  // PrintJob will create the new PrintedDocument.
  owner_->message_loop()->PostTask(
      FROM_HERE,
      base::Bind(&PrintJobWorkerOwner::GetSettingsDone,
                 make_scoped_refptr(owner_), printing_context_->settings(),
                 result));
}

void PrintJobWorker::GetSettingsWithUI(
    scoped_ptr<PrintingUIWebContentsObserver> web_contents_observer,
    int document_page_count,
    bool has_selection) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));

  gfx::NativeView parent_view = web_contents_observer->GetParentView();
  if (!parent_view) {
    GetSettingsWithUIDone(printing::PrintingContext::FAILED);
    return;
  }
  printing_context_->AskUserForSettings(
      parent_view, document_page_count, has_selection,
      base::Bind(&PrintJobWorker::GetSettingsWithUIDone,
                 base::Unretained(this)));
}

void PrintJobWorker::GetSettingsWithUIDone(PrintingContext::Result result) {
  message_loop()->PostTask(
      FROM_HERE,
      base::Bind(&HoldRefCallback, make_scoped_refptr(owner_),
                 base::Bind(&PrintJobWorker::GetSettingsDone,
                            base::Unretained(this), result)));
}

void PrintJobWorker::UseDefaultSettings() {
  PrintingContext::Result result = printing_context_->UseDefaultSettings();
  GetSettingsDone(result);
}

void PrintJobWorker::StartPrinting(PrintedDocument* new_document) {
  DCHECK_EQ(message_loop(), base::MessageLoop::current());
  DCHECK_EQ(page_number_, PageNumber::npos());
  DCHECK_EQ(document_, new_document);
  DCHECK(document_.get());

  if (!document_.get() || page_number_ != PageNumber::npos() ||
      document_.get() != new_document) {
    return;
  }

  base::string16 document_name =
      printing::SimplifyDocumentTitle(document_->name());
  if (document_name.empty()) {
    document_name = printing::SimplifyDocumentTitle(
        l10n_util::GetStringUTF16(IDS_DEFAULT_PRINT_DOCUMENT_TITLE));
  }
  PrintingContext::Result result =
      printing_context_->NewDocument(document_name);
  if (result != PrintingContext::OK) {
    OnFailure();
    return;
  }

  // Try to print already cached data. It may already have been generated for
  // the print preview.
  OnNewPage();
  // Don't touch this anymore since the instance could be destroyed. It happens
  // if all the pages are printed a one sweep and the client doesn't have a
  // handle to us anymore. There's a timing issue involved between the worker
  // thread and the UI thread. Take no chance.
}

void PrintJobWorker::OnDocumentChanged(PrintedDocument* new_document) {
  DCHECK_EQ(message_loop(), base::MessageLoop::current());
  DCHECK_EQ(page_number_, PageNumber::npos());

  if (page_number_ != PageNumber::npos())
    return;

  document_ = new_document;
}

void PrintJobWorker::OnNewPage() {
  if (!document_.get())  // Spurious message.
    return;

  // message_loop() could return NULL when the print job is cancelled.
  DCHECK_EQ(message_loop(), base::MessageLoop::current());

  if (page_number_ == PageNumber::npos()) {
    // Find first page to print.
    int page_count = document_->page_count();
    if (!page_count) {
      // We still don't know how many pages the document contains. We can't
      // start to print the document yet since the header/footer may refer to
      // the document's page count.
      return;
    }
    // We have enough information to initialize page_number_.
    page_number_.Init(document_->settings(), page_count);
    if (destination_.get() != NULL)
      destination_->SetPageCount(page_count);
  }
  DCHECK_NE(page_number_, PageNumber::npos());

  while (true) {
    // Is the page available?
    scoped_refptr<PrintedPage> page;
    if (!document_->GetPage(page_number_.ToInt(), &page)) {
      // We need to wait for the page to be available.
      base::MessageLoop::current()->PostDelayedTask(
          FROM_HERE,
          base::Bind(&PrintJobWorker::OnNewPage, weak_factory_.GetWeakPtr()),
          base::TimeDelta::FromMilliseconds(500));
      break;
    }
    // The page is there, print it.
    SpoolPage(page.get());
    ++page_number_;
    if (page_number_ == PageNumber::npos()) {
      OnDocumentDone();
      // Don't touch this anymore since the instance could be destroyed.
      break;
    }
  }
}

void PrintJobWorker::Cancel() {
  // This is the only function that can be called from any thread.
  printing_context_->Cancel();
  // Cannot touch any member variable since we don't know in which thread
  // context we run.
}

void PrintJobWorker::OnDocumentDone() {
  DCHECK_EQ(message_loop(), base::MessageLoop::current());
  DCHECK_EQ(page_number_, PageNumber::npos());
  DCHECK(document_.get());

  if (printing_context_->DocumentDone() != PrintingContext::OK) {
    OnFailure();
    return;
  }

  owner_->message_loop()->PostTask(
      FROM_HERE, base::Bind(NotificationCallback, make_scoped_refptr(owner_),
                            JobEventDetails::DOC_DONE, document_,
                            scoped_refptr<PrintedPage>()));

  // Makes sure the variables are reinitialized.
  document_ = NULL;
}

void PrintJobWorker::SpoolPage(PrintedPage* page) {
  DCHECK_EQ(message_loop(), base::MessageLoop::current());
  DCHECK_NE(page_number_, PageNumber::npos());

  // Signal everyone that the page is about to be printed.
  owner_->message_loop()->PostTask(
      FROM_HERE, base::Bind(NotificationCallback, make_scoped_refptr(owner_),
                            JobEventDetails::NEW_PAGE, document_,
                            make_scoped_refptr(page)));

  // Preprocess.
  if (printing_context_->NewPage() != PrintingContext::OK) {
    OnFailure();
    return;
  }

  if (destination_.get() != NULL) {
    std::vector<uint8> metabytes(page->metafile()->GetDataSize());
    bool success = page->metafile()->GetData(
        reinterpret_cast<void*>(&metabytes[0]), metabytes.size());
    DCHECK(success) << "Failed to get metafile data.";
    destination_->SetPageContent(
        page->page_number(),
        reinterpret_cast<void*>(&metabytes[0]),
        metabytes.size());
    return;
  }

  // Actual printing.
#if defined(OS_WIN) || defined(OS_MACOSX)
  document_->RenderPrintedPage(*page, printing_context_->context());
#elif defined(OS_POSIX)
  document_->RenderPrintedPage(*page, printing_context_.get());
#endif

  // Postprocess.
  if (printing_context_->PageDone() != PrintingContext::OK) {
    OnFailure();
    return;
  }

  // Signal everyone that the page is printed.
  owner_->message_loop()->PostTask(
      FROM_HERE,
      base::Bind(NotificationCallback, make_scoped_refptr(owner_),
                 JobEventDetails::PAGE_DONE, document_,
                 make_scoped_refptr(page)));
}

void PrintJobWorker::OnFailure() {
  DCHECK_EQ(message_loop(), base::MessageLoop::current());

  // We may loose our last reference by broadcasting the FAILED event.
  scoped_refptr<PrintJobWorkerOwner> handle(owner_);

  owner_->message_loop()->PostTask(
      FROM_HERE, base::Bind(NotificationCallback, make_scoped_refptr(owner_),
                            JobEventDetails::FAILED, document_,
                            scoped_refptr<PrintedPage>()));
  Cancel();

  // Makes sure the variables are reinitialized.
  document_ = NULL;
  page_number_ = PageNumber::npos();
}

}  // namespace printing