PrintPreview: Print Preview is not staying associated with initiator renderer.

chrome/browser/ui/webui/print_preview_data_source.h

+// 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.
+
+#ifndef CHROME_BROWSER_UI_WEBUI_PRINT_PREVIEW_DATA_SOURCE_H_
+#define CHROME_BROWSER_UI_WEBUI_PRINT_PREVIEW_DATA_SOURCE_H_
+#pragma once
+
+#include <map>
+#include <string>
+#include <utility>
+
+#include "chrome/browser/ui/webui/chrome_url_data_manager.h"
+
+template<typename T> struct LeakySingletonTraits;
+
+class PrintPreviewUI;
+
+namespace base {
+class SharedMemory;
+}
+
+// PrintPreviewDataSource serves data for chrome://print requests.
+//
+// PrintPreviewDataSource owns the data and is responsible for freeing it when
+// either:
+//    a) there is a new data.
+//    b) When PrintPreviewDataSource is destroyed.
+//
+// The format for requesting data is as follows:
+// chrome://print/print.pdf/<PrintPreviewUIAddrStr>
+//
+// Parameters (< > required):
+//    <PrintPreviewUIAddrStr> = Print preview UI identifier.
+//
+// Example:
+//    chrome://print/print.pdf/0x7f5470fbe510
+
+class PrintPreviewDataSource : public ChromeURLDataManager::DataSource {
+ public:
+  // A SharedMemory that contains the data for print preview,
+  // and the size of the print preview data in bytes.
+  typedef std::pair<base::SharedMemory*, uint32> PrintPreviewData;

[sky, 2011/05/25 20:57:35]

To make lifetime management easier, could this take RefCountedBytes? That way
you don't have to delete at line 191 new in print_preview_data_source.cc, and
you don't have to worry about leaking in destructor.

[kmadhusu, 2011/05/25 23:45:21]

I understand your concern. Just to be consistent with rest of the print preview
data structures, I used SharedMemory here. 

[sky, 2011/05/26 17:40:41]

Shouldn't you be striving for less error prone code? Even so, you could still
take a SharedMemory but internally use RefCountedBytes. Especially since this
class ends up serving RefCountedBytes.

+
+  typedef std::string PreviewUIAddrStr;
+
+  // 1:1 relationship between PrintPreviewUI and preview data.
+  // Key: Print preview UI address string.
+  // Value: Preview data.
+  typedef std::map<PreviewUIAddrStr, PrintPreviewData> PreviewDataSrcMap;
+
+  // Getter for the singleton.
+  static PrintPreviewDataSource* GetInstance();

[sky, 2011/05/25 20:57:35]

nit: constructor/destructor before static methods.

[kmadhusu, 2011/05/25 23:45:21]

Done.

+
+  PrintPreviewDataSource();

[sky, 2011/05/25 20:57:35]

Is it possible to make the constructor private?

[kmadhusu, 2011/05/25 23:45:21]

Since I am using "LeakySingleTonTraits", it needs to be public.

+  virtual ~PrintPreviewDataSource();
+
+  // Remove the corresponding PrintPreviewUI entry from the map.
+  void RemoveEntry(const PreviewUIAddrStr& preview_ui_addr_str);
+
+  // Set/Update the data entry in PreviewDataSrcMap.
+  void SetDataEntry(const PreviewUIAddrStr& preview_ui_addr_str,
+                    const PrintPreviewData& data);
+
+  // Get the data entry from PreviewDataSrcMap.
+  void GetDataEntry(const PreviewUIAddrStr& preview_ui_addr_str,
+                    PrintPreviewData* data);
+
+  // ChromeURLDataManager::DataSource implementation.
+  virtual void StartDataRequest(const std::string& path,

[sky, 2011/05/25 20:57:35]

nit: Use OVERRIDE here and 73.

[kmadhusu, 2011/05/25 23:45:21]

Done.

+                                bool is_incognito,
+                                int request_id);
+  virtual std::string GetMimeType(const std::string& path) const;
+
+ private:
+  friend struct LeakySingletonTraits<PrintPreviewDataSource>;
+
+  PreviewDataSrcMap data_source_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrintPreviewDataSource);
+};
+
+#endif  // CHROME_BROWSER_UI_WEBUI_PRINT_PREVIEW_DATA_SOURCE_H_