Print Preview: Hook up the print button to initiate printing without displaying a print dialog.

chrome/browser/printing/printer_query.cc

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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/printer_query.h"
 
 #include "base/message_loop.h"
 #include "base/threading/thread_restrictions.h"
+#include "base/values.h"
 #include "chrome/browser/printing/print_job_worker.h"
 
 namespace printing {
 
 PrinterQuery::PrinterQuery()
     : io_message_loop_(MessageLoop::current()),
       ALLOW_THIS_IN_INITIALIZER_LIST(worker_(new PrintJobWorker(this))),
       is_print_dialog_box_shown_(false),
       cookie_(PrintSettings::NewCookie()),
       last_status_(PrintingContext::FAILED) {
@@ skipping 52 matching lines @@
 }
 
 void PrinterQuery::GetSettings(GetSettingsAskParam ask_user_for_settings,
                                gfx::NativeView parent_view,
                                int expected_page_count,
                                bool has_selection,
                                bool use_overlays,
                                CancelableTask* callback) {
   DCHECK_EQ(io_message_loop_, MessageLoop::current());
   DCHECK(!is_print_dialog_box_shown_);
+  if (!StartWorker(callback))
+    return;
+
+  // Real work is done in PrintJobWorker::Init().
+  is_print_dialog_box_shown_ = ask_user_for_settings == ASK_USER;
+  worker_->message_loop()->PostTask(FROM_HERE, NewRunnableMethod(
+      worker_.get(),
+      &PrintJobWorker::GetSettings,
+      is_print_dialog_box_shown_,
+      parent_view,
+      expected_page_count,
+      has_selection,
+      use_overlays));
+}
+
+void PrinterQuery::SetSettings(const DictionaryValue& new_settings,
+                               CancelableTask* callback) {
+  if (!StartWorker(callback))
+    return;
+
+  scoped_ptr<DictionaryValue> new_settings_copy(new_settings.DeepCopy());

[Lei Zhang, 2011/03/03 00:22:44]

Probably don't need the scoped_ptr if you are allocating it and immediately
releasing it.

[kmadhusu, 2011/03/04 19:39:02]

Done.

+  worker_->message_loop()->PostTask(FROM_HERE, NewRunnableMethod(
+      worker_.get(),
+      &PrintJobWorker::SetSettings,
+      new_settings_copy.release()));
+}
+
+bool PrinterQuery::StartWorker(CancelableTask* callback) {
   DCHECK(!callback_.get());
   DCHECK(worker_.get());
   if (!worker_.get())
-    return;
+    return false;
+
   // Lazy create the worker thread. There is one worker thread per print job.
   if (!worker_->message_loop()) {
     if (!worker_->Start()) {
       if (callback) {
         callback->Cancel();
         delete callback;
       }
       NOTREACHED();
-      return;
+      return false;
     }
   }
-
   callback_.reset(callback);
-  // Real work is done in PrintJobWorker::Init().
-  is_print_dialog_box_shown_ = ask_user_for_settings == ASK_USER;
-  worker_->message_loop()->PostTask(FROM_HERE, NewRunnableMethod(
-      worker_.get(),
-      &PrintJobWorker::GetSettings,
-      is_print_dialog_box_shown_,
-      parent_view,
-      expected_page_count,
-      has_selection,
-      use_overlays));
+  return true;
 }
 
 void PrinterQuery::StopWorker() {
   if (worker_.get()) {
     // http://crbug.com/66082: We're blocking on the PrinterQuery's worker
     // thread.  It's not clear to me if this may result in blocking the current
     // thread for an unacceptable time.  We should probably fix it.
     base::ThreadRestrictions::ScopedAllowIO allow_io;
     worker_->Stop();
     worker_.reset();
   }
 }
 
 bool PrinterQuery::is_callback_pending() const {
   return callback_.get() != NULL;
 }
 
 bool PrinterQuery::is_valid() const {
   return worker_.get() != NULL;
 }
 
 }  // namespace printing