AppCachePlumbing

webkit/glue/webappcachecontext.h

+// Copyright (c) 2009 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 WEBKIT_GLUE_WEBAPPCACHECONTEXT_H_
+#define WEBKIT_GLUE_WEBAPPCACHECONTEXT_H_
+
+#include "base/basictypes.h"
+
+class GURL;
+
+// This class is used in child processes, renderers and workers.
+//
+// An AppCacheContext corresponds with what html5 refers to as a
+// "browsing context". Conceptually, each frame or worker represents
+// a unique context. This class is used in child processes (renderers
+// and workers) to inform the browser process of new frames and workers, and
+// to keep track of which appcache is selected for each context. Resource
+// requests contain the context id so the browser process can identify
+// which context a request came from. As new documents are committed into a
+// frame, the cache selection algorithm is initiated by calling one of the
+// SelectAppCache methods.
+//
+// Each WebAppCacheContext is assigned a unique id within its child process.
+// These ids are made globally unique by pairing them with a child process
+// id within the browser process.
+//
+// WebFrameImpl has a scoped ptr to one of these as a data member.
+// TODO(michaeln): integrate with WebWorkers
+class WebAppCacheContext {
+ public:
+  enum ContextType {
+    MAIN_FRAME = 0,
+    CHILD_FRAME,
+    DEDICATED_WORKER
+  };
+
+  static const int kNoAppCacheContextId;  // = 0;
+  static const int64 kNoAppCacheId;       // = 0;
+  static const int64 kUnknownAppCacheId;  // = -1;
+
+  // Factory method called internally by webkit_glue to create a concrete
+  // instance of this class. If SetFactory has been called, the factory
+  // function provided there is used to create a new instance, otherwise
+  // a noop implementation is returned.
+  static WebAppCacheContext* Create();
+
+  typedef WebAppCacheContext* (*WebAppCacheFactoryProc)(void);
+  static void SetFactory(WebAppCacheFactoryProc factory_proc);
+
+  // Unique id within the child process housing this context
+  virtual int context_id() = 0;

[darin (slow to review), 2009/04/13 18:37:54]

nit: virtual methods should not be named unix_hacker style since you cannot by
definition be cheap to call.

+
+  // Which appcache is associated with the context. There are windows of
+  // time where the appcache is not yet known, the return value is
+  // kUnknownAppCacheId in that case.
+  virtual int64 app_cache_id() = 0;

[darin (slow to review), 2009/04/13 18:37:54]

ditto

+
+  // The following methods result in async messages being sent to the
+  // browser process. The initialize method tell the browser process about
+  // the existance of this context, its type and its id. The select methods
+  // tell the browser process to initiate the cache selection algorithm for
+  // the context.
+  virtual void Initialize(ContextType context_type,
+                          WebAppCacheContext* opt_parent) = 0;
+  virtual void SelectAppCacheWithoutManifest(
+                                     const GURL& document_url,
+                                     int64 cache_document_was_loaded_from) = 0;
+  virtual void SelectAppCacheWithManifest(
+                                     const GURL& document_url,
+                                     int64 cache_document_was_loaded_from,
+                                     const GURL& manifest_url) = 0;
+
+  virtual ~WebAppCacheContext() {}
+};
+
+#endif  // WEBKIT_GLUE_WEBAPPCACHECONTEXT_H_