Separate WebDataRequest functionality from WebDataService

chrome/browser/webdata/web_data_request_manager.h

+// Copyright 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.
+
+// Chromium settings and storage represent user-selected preferences and
+// information and MUST not be extracted, overwritten or modified except
+// through Chromium defined APIs.
+
+#ifndef CHROME_BROWSER_WEBDATA_WEB_DATA_REQUEST_MANAGER_H__
+#define CHROME_BROWSER_WEBDATA_WEB_DATA_REQUEST_MANAGER_H__
+
+#include <map>
+
+#include "base/memory/ref_counted.h"
+#include "base/synchronization/lock.h"
+#include "chrome/browser/api/webdata/web_data_results.h"
+#include "chrome/browser/api/webdata/web_data_service_base.h"
+#include "chrome/browser/api/webdata/web_data_service_consumer.h"
+
+class MessageLoop;
+class WebDataService;
+class WebDataServiceConsumer;
+class WebDataRequestManager;
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// Webdata requests
+//
+// Every request is processed using a request object. The object contains
+// both the request parameters and the results.
+//////////////////////////////////////////////////////////////////////////////
+class WebDataRequest {
+ public:
+  WebDataRequest(WebDataService* service,
+                 WebDataServiceConsumer* consumer,
+                 WebDataRequestManager* manager);
+
+  virtual ~WebDataRequest();
+
+  WebDataServiceBase::Handle GetHandle() const;
+
+  // Retrieves the |consumer_| set in the constructor.
+  WebDataServiceConsumer* GetConsumer() const;
+
+  // Returns |true| if the request was cancelled via the |Cancel()| method.
+  bool IsCancelled() const;
+
+  // This can be invoked from any thread. From this point we assume that
+  // our consumer_ reference is invalid.
+  void Cancel();
+
+  // Invoked by the service when this request has been completed.
+  // This will notify the service in whatever thread was used to create this
+  // request.
+  void RequestComplete();
+
+  // The result is owned by the request.
+  void SetResult(WDTypedResult* r);
+  const WDTypedResult* GetResult() const;
+
+ private:
+  // Used to notify service of request completion.
+  scoped_refptr<WebDataService> service_;
+
+  // Tracks loop that the request originated on.
+  MessageLoop* message_loop_;
+
+  // Identifier for this request.
+  WebDataServiceBase::Handle handle_;
+
+  // A lock to protect against simultaneous cancellations of the request.
+  // Cancellation affects both the |cancelled_| flag and |consumer_|.
+  mutable base::Lock cancel_lock_;
+  bool cancelled_;
+
+  // The originator of the service request.
+  WebDataServiceConsumer* consumer_;
+
+  WDTypedResult* result_;
+
+  DISALLOW_COPY_AND_ASSIGN(WebDataRequest);
+};
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// Webdata request templates
+//
+// Internally we use instances of the following template to represent
+// requests.
+//////////////////////////////////////////////////////////////////////////////
+
+template <class T>
+class GenericRequest : public WebDataRequest {
+ public:
+  GenericRequest(WebDataService* service,
+                 WebDataServiceConsumer* consumer,
+                 WebDataRequestManager* manager,
+                 const T& arg)
+      : WebDataRequest(service, consumer, manager),
+        arg_(arg) {
+  }
+
+  virtual ~GenericRequest() {
+  }
+
+  const T& arg() const { return arg_; }
+
+ private:
+  T arg_;
+};
+
+template <class T, class U>
+class GenericRequest2 : public WebDataRequest {
+ public:
+  GenericRequest2(WebDataService* service,
+                  WebDataServiceConsumer* consumer,
+                  WebDataRequestManager* manager,
+                  const T& arg1,
+                  const U& arg2)
+      : WebDataRequest(service, consumer, manager),
+        arg1_(arg1),
+        arg2_(arg2) {
+  }
+
+  virtual ~GenericRequest2() { }
+
+  const T& arg1() const { return arg1_; }
+
+  const U& arg2() const { return arg2_; }
+
+ private:
+  T arg1_;
+  U arg2_;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// Webdata Request Manager
+//
+// Tracks all WebDataRequests for a WebDataService.
+//
+// Note: This is an internal interface, not to be used outside of webdata/
+//////////////////////////////////////////////////////////////////////////////
+class WebDataRequestManager {
+ public:
+  WebDataRequestManager();
+
+  ~WebDataRequestManager();
+
+  // Cancel any pending request.
+  void CancelRequest(WebDataServiceBase::Handle h);
+
+  // Invoked by request implementations when a request has been processed.
+  void RequestCompleted(WebDataServiceBase::Handle h);
+
+  // Register the request as a pending request.
+  void RegisterRequest(WebDataRequest* request);
+
+  // Return the next request handle.
+  int GetNextRequestHandle();
+
+ private:
+  // A lock to protect pending requests and next request handle.
+  base::Lock pending_lock_;
+
+  // Next handle to be used for requests. Incremented for each use.
+  WebDataServiceBase::Handle next_request_handle_;
+
+  typedef std::map<WebDataServiceBase::Handle, WebDataRequest*> RequestMap;
+  RequestMap pending_requests_;
+
+  DISALLOW_COPY_AND_ASSIGN(WebDataRequestManager);
+};
+
+#endif  // CHROME_BROWSER_WEBDATA_WEB_DATA_REQUEST_MANAGER_H__