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

chrome/browser/printing/print_job_worker.cc

 // 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/print_job_worker.h"
 
+#include "base/json/json_reader.h"
 #include "base/message_loop.h"
+#include "base/values.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_thread.h"
 #include "chrome/browser/printing/print_job.h"
 #include "chrome/common/notification_service.h"
 #include "printing/printed_document.h"
 #include "printing/printed_page.h"
 
 namespace printing {
 
 class PrintJobWorker::NotificationTask : public Task {
@@ skipping 73 matching lines @@
         BrowserThread::UI, FROM_HERE,
         NewRunnableMethod(this, &PrintJobWorker::GetSettingsWithUI,
                           parent_view, document_page_count,
                           has_selection));
   } else {
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
         NewRunnableMethod(this, &PrintJobWorker::UseDefaultSettings));
   }
 }
 
+void PrintJobWorker::SetSettings(const std::string& new_settings) {
+  DCHECK_EQ(message_loop(), MessageLoop::current());
+  DCHECK_EQ(page_number_, PageNumber::npos());
+
+  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
+      NewRunnableMethod(this, &PrintJobWorker::UpdatePrintSettings,
+                        new_settings));
+}
+
+void PrintJobWorker::UpdatePrintSettings(const std::string& new_settings) {

[Lei Zhang, 2011/02/24 03:49:32]

Have you considered parsing (and maybe validating) the json string when you
first get it in PrintPreviewHandler::HandlePrint(), and just pass a
DictionaryValue around. It's better to validate first and drop the request on
the floor if it doesn't make any sense, than to do a bunch of work, only then to
realize you can't continue due to bad settings.

[kmadhusu, 2011/03/01 01:55:50]

Fixed. Now UpdatePrintSettings() has a dictionary value as a parameter.

+  scoped_ptr<Value> parsed_value(base::JSONReader::Read(new_settings, false));
+  if (!parsed_value.get() || !parsed_value->IsType(Value::TYPE_DICTIONARY)) {
+    NOTREACHED() << "Unable to parse print params";
+    return;
+  }
+  DictionaryValue* settings =

[Lei Zhang, 2011/02/24 03:49:32]

nit: you don't need separate |settings| and |parsed_value| variables.

[kmadhusu, 2011/03/01 01:55:50]

Done.

+      static_cast<DictionaryValue*>(parsed_value.get());
+
+  // Create new PageRanges based on |new_settings|.
+  PageRanges new_ranges;
+  ListValue* pageRangeArray = NULL;

[Lei Zhang, 2011/02/24 03:49:32]

you don't need this assignment or the ones below for |printFrom| and |printTo|,
since you'll never use the variable if the DictionaryValue.GetFoo() call fails.

[kmadhusu, 2011/03/01 01:55:50]

Done.

+  if (settings->GetList("pageRange", &pageRangeArray)) {
+    for (size_t index = 0; index < pageRangeArray->GetSize(); index++) {
+      DictionaryValue* dict = NULL;
+      pageRangeArray->GetDictionary(index, &dict);
+      if (dict) {
+        int printFrom = 0;

[Lei Zhang, 2011/02/24 03:49:32]

Can you get rid of |printFrom| and |printTo|, instead do:

PageRange range;
if (dict->GetInteger("from", &range.from) &&
    dict->GetInteger("to", &range.to)) {
  // Page numbers are 0-based.
  range.from--;
  range.to--;
  new_ranges.push_back(range);
}

[kmadhusu, 2011/03/01 01:55:50]

Done.

+        int printTo = 0;
+        if (dict->GetInteger("from", &printFrom) &&
+            dict->GetInteger("to", &printTo)) {
+          PageRange range;
+          // Page numbers are 0-based.
+          range.from = printFrom - 1;
+          range.to = printTo - 1;
+          new_ranges.push_back(range);
+        }
+      }
+    }
+  }
+  PrintingContext::Result result =
+      printing_context_->UpdatePrintSettings(new_ranges);
+  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.
 
@@ skipping 205 matching lines @@
     printing::PrintJobWorker* obj) {
   DCHECK(!owner_.get());
   owner_ = obj->owner_;
 }
 
 void RunnableMethodTraits<printing::PrintJobWorker>::ReleaseCallee(
     printing::PrintJobWorker* obj) {
   DCHECK_EQ(owner_, obj->owner_);
   owner_ = NULL;
 }