Check-in rlz code to src\rlz from http://code.google.com/p/rlz/.

rlz/lib/rlz_value_store.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 RLZ_VALUE_STORE_H_
+#define RLZ_VALUE_STORE_H_
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "rlz/lib/rlz_enums.h"
+
+#if defined(OS_WIN)
+#include "rlz/win/lib/lib_mutex.h"
+#endif
+
+#if defined(OS_MACOSX)
+#include "base/mac/scoped_nsautorelease_pool.h"
+#endif
+
+
+#include <string>
+#include <vector>
+
+class FilePath;
+
+namespace rlz_lib {
+
+// Abstracts away rlz's key value store. On windows, this usually writes to
+// the registry. On mac, it writes to an NSDefaults object.
+class RlzValueStore {
+ public:
+  virtual ~RlzValueStore() {}
+
+  enum AccessType { kReadAccess, kWriteAccess };
+  virtual bool HasAccess(AccessType type) = 0;
+
+  // Ping times.
+  virtual bool WritePingTime(Product product, int64 time) = 0;
+  virtual bool ReadPingTime(Product product, int64* time) = 0;
+  virtual bool ClearPingTime(Product product) = 0;
+
+  // Access point RLZs.
+  virtual bool WriteAccessPointRlz(AccessPoint access_point,
+                                   const char* new_rlz) = 0;
+  virtual bool ReadAccessPointRlz(AccessPoint access_point,
+                                  char* rlz,  // At most kMaxRlzLength + 1 bytes
+                                  size_t rlz_size) = 0;
+  virtual bool ClearAccessPointRlz(AccessPoint access_point) = 0;
+
+  // Product events.
+  // Stores |event_rlz| for product |product| as product event.
+  virtual bool AddProductEvent(Product product, const char* event_rlz) = 0;
+  // Appends all events for |product| to |events|, in arbirtrary order.
+  virtual bool ReadProductEvents(Product product,
+                                 std::vector<std::string>* events) = 0;
+  // Removes the stored event |event_rlz| for |product| if it exists.
+  virtual bool ClearProductEvent(Product product, const char* event_rlz) = 0;
+  // Removes all stored product events for |product|.
+  virtual bool ClearAllProductEvents(Product product) = 0;
+
+  // Stateful events.
+  // Stores |event_rlz| for product |product| as stateful event.
+  virtual bool AddStatefulEvent(Product product, const char* event_rlz) = 0;
+  // Checks if |event_rlz| has been stored as stateful event for |product|.
+  virtual bool IsStatefulEvent(Product product, const char* event_rlz) = 0;
+  // Removes all stored stateful events for |product|.
+  virtual bool ClearAllStatefulEvents(Product product) = 0;
+
+  // Tells the value store to clean up unimportant internal data structures, for
+  // example empty registry folders, that might remain after clearing other
+  // data. Best-effort.
+  virtual void CollectGarbage() = 0;
+};
+
+// All methods of RlzValueStore must stays consistent even when accessed from
+// multiple threads in multiple processes. To enforce this through the type
+// system, the only way to access the RlzValueStore is through a
+// ScopedRlzValueStoreLock, which is a cross-process lock. It is active while
+// it is in scope. If the class fails to acquire a lock, its GetStore() method
+// returns NULL. If the lock fails to be acquired, it must not be taken
+// recursively. That is, all user code should look like this:
+//   ScopedRlzValueStoreLock lock;
+//   RlzValueStore* store = lock.GetStore();
+//   if (!store)
+//     return some_error_code;
+//   ...
+class ScopedRlzValueStoreLock {
+ public:
+  ScopedRlzValueStoreLock();
+  ~ScopedRlzValueStoreLock();
+
+  // Returns a RlzValueStore protected by a cross-process lock, or NULL if the
+  // lock can't be obtained. The lifetime of the returned object is limited to
+  // the lifetime of this ScopedRlzValueStoreLock object.
+  RlzValueStore* GetStore();
+
+ private:
+  scoped_ptr<RlzValueStore> store_;
+#if defined(OS_WIN)
+  LibMutex lock_;
+#else
+  base::mac::ScopedNSAutoreleasePool autorelease_pool_;
+#endif
+};
+
+#if defined(OS_MACOSX)
+namespace testing {
+// Prefix |directory| to the path where the RLZ data file lives, for tests.
+void SetRlzStoreDirectory(const FilePath& directory);
+}  // namespace testing
+#endif  // defined(OS_MACOSX)
+
+
+}  // namespace rlz_lib
+
+#endif  // RLZ_VALUE_STORE_H_