Refactoring the SysInfoProvider.

chrome/browser/chromeos/system_logs/system_logs_fetcher.h

+// 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.
+
+#ifndef CHROME_BROWSER_CHROMEOS_SYSTEM_LOGS_SYSTEM_LOGS_FETCHER_H_
+#define CHROME_BROWSER_CHROMEOS_SYSTEM_LOGS_SYSTEM_LOGS_FETCHER_H_
+
+#include <map>
+#include <string>
+
+#include "base/callback.h"
+#include "base/memory/weak_ptr.h"
+#include "base/memory/scoped_vector.h"
+namespace chromeos {
+
+typedef std::map<std::string, std::string> SystemLogsResponse;
+typedef base::Callback<void(SystemLogsResponse*)> SysLogsFetcherCallback;
+
+// The SystemLogsSource provides a interface for the data sources that
+// the SystemLogsFetcher class uses to fetch logs and other
+// information.
+class SystemLogsSource {
+ public:
+  // Fetches data and passes it by to the callback
+  virtual void Fetch(const SysLogsFetcherCallback& request) = 0;
+  virtual ~SystemLogsSource() {}
+};
+
+// The SystemLogsFetcher creates a list of data sources which must be
+// classes that implement the SystemLogsSource. It's Fetch function
+// receives as a parameter a callback that takes only one parameter
+// SystemLogsResponse that is a map of keys and values.
+// Each data source also returns a SystemLogsResponse. If two data sources
+// return the same key, the last one will replace the previous one.
+// The class runs on the UI thread.
+//
+// EXAMPLE:
+// class Example {
+//   public:
+//      ProcessLogs(chrome::SystemLogsResponse) {
+//        //do something with the logs
+//      }
+//      GetLogs() {
+//        chrome::SystemLogsFetcher* fetcher =
+//          chrome::SystemLogsFetcher::GetInstance()->CreateFetcher();
+//        fetcher->Fetch(base::Bind(&Example::ProcessLogs, this));
+//      }
+class SystemLogsFetcher {
+ public:
+  explicit SystemLogsFetcher();
+  ~SystemLogsFetcher() {}
+
+  void Fetch(const SysLogsFetcherCallback& request);
+
+ private:
+  // Callback passed to all the data sources. It merges the |data| it recieves
+  // into response_. When all the data sources have responded, it deletes their
+  // objects and returns the response to the request_ callback. After this it
+  // deletes itself.
+  void AddResponse(SystemLogsResponse* callback);

[satorux1, 2012/08/15 22:01:09]

response. this is not callback, right?

[tudalex(Chromium), 2012/08/16 01:08:57]

Yes. Done.

+
+  ScopedVector<SystemLogsSource> data_sources_;
+  SysLogsFetcherCallback request_;
+
+  SystemLogsResponse* response_;  // The actual response data.
+  size_t num_pending_requests_;   // The number of callbacks it should get.
+
+  base::WeakPtrFactory<SystemLogsFetcher> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(SystemLogsFetcher);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_SYSTEM_LOGS_SYSTEM_LOGS_FETCHER_H_
+