Identity API: getAuthToken request queues (token cache prelude)

chrome/browser/extensions/api/identity/identity_mint_queue.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_EXTENSIONS_API_IDENTITY_IDENTITY_MINT_QUEUE_H_
+#define CHROME_BROWSER_EXTENSIONS_API_IDENTITY_IDENTITY_MINT_QUEUE_H_
+
+#include <list>
+#include <map>
+#include <set>
+#include <string>
+
+namespace extensions {
+
+// getAuthToken requests are serialized to avoid excessive traffic to
+// GAIA and to consolidate UI pop-ups. IdentityMintRequestQueue
+// maitains a set of queues, one for each RequestKey.
+//
+// The queue calls StartMintToken on each Request when it reaches the
+// head of the line.
+//
+// The queue does not own Requests. Request pointers must be valid
+// until they are removed from the queue with RequestComplete.
+class IdentityMintRequestQueue {
+ public:
+  enum MintType {
+    MINT_TYPE_NONINTERACTIVE,
+    MINT_TYPE_INTERACTIVE
+  };
+
+  IdentityMintRequestQueue();
+  virtual ~IdentityMintRequestQueue();
+
+  class Request {
+   public:
+    virtual ~Request() {}
+    virtual void StartMintToken(IdentityMintRequestQueue::MintType type) = 0;
+  };
+
+  struct RequestKey {
+    RequestKey(IdentityMintRequestQueue::MintType type,
+               const std::string& extension_id,
+               const std::set<std::string> scopes);
+    ~RequestKey();
+    bool operator<(const RequestKey& rhs) const;
+    IdentityMintRequestQueue::MintType type;
+    std::string extension_id;
+    std::set<std::string> scopes;
+  };
+
+  // Adds a request to the queue specified by the id and scopes.
+  void RequestStart(IdentityMintRequestQueue::MintType type,
+                    const std::string& extension_id,
+                    const std::set<std::string> scopes,
+                    IdentityMintRequestQueue::Request* request);
+  // Removes a request from the queue specified by the id and scopes.
+  void RequestComplete(IdentityMintRequestQueue::MintType type,
+                       const std::string& extension_id,
+                       const std::set<std::string> scopes,
+                       IdentityMintRequestQueue::Request* request);
+  bool empty(IdentityMintRequestQueue::MintType type,
+             const std::string& extension_id,
+             const std::set<std::string> scopes) const;
+
+ private:
+  typedef std::list<IdentityMintRequestQueue::Request*> RequestList;
+  std::map<RequestKey, RequestList> request_queue_;
+};
+
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_IDENTITY_IDENTITY_MINT_QUEUE_H_