Add PNaCl translation cache based on Chrome disk_cache

chrome/browser/nacl_host/pnacl_translation_cache.h

Index: chrome/browser/nacl_host/pnacl_translation_cache.h
diff --git a/chrome/browser/nacl_host/pnacl_translation_cache.h b/chrome/browser/nacl_host/pnacl_translation_cache.h
new file mode 100644
index 0000000000000000000000000000000000000000..0a543298a7cf04a3d0ad0629dd2c0a874a2e1371
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+++ b/chrome/browser/nacl_host/pnacl_translation_cache.h
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+// Copyright (c) 2013 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_NACL_HOST_PNACL_TRANSLATION_CACHE_H_
+#define CHROME_BROWSER_NACL_HOST_PNACL_TRANSLATION_CACHE_H_
+
+#include <map>
+
+#include "base/callback.h"
+#include "base/files/file_path.h"
+#include "base/memory/weak_ptr.h"
+#include "net/base/cache_type.h"
+
+namespace base {
+class MessageLoopProxy;
+}
+
+namespace disk_cache {
+class Backend;
+}
+
+namespace pnacl_cache {
+typedef base::Callback<void(int)> CompletionCallback;
+class PNaClTranslationCacheWriteEntry;
+extern const int kMaxMemCacheSize;
+
+class PNaClTranslationCache
+    : public base::SupportsWeakPtr<PNaClTranslationCache> {
+ public:
+  PNaClTranslationCache();
+  virtual ~PNaClTranslationCache();
+
+  // Initialize the translation cache in |cache_dir| (or in memory if
+  // |in_memory| is true). Call |callback| with a 0 argument on sucess and
+  // <0 otherwise.
+  int InitCache(const base::FilePath& cache_dir,
+                bool in_memory,
+                const CompletionCallback& callback);
+
+  // Store the nexe in the translation cache.
+  void StoreNexe(const std::string& key, const std::string& nexe);
+
+  // Store the nexe in the translation cache, and call |callback| with
+  // the result. The result passed to the callback is 0 on success and
+  // <0 otherwise.
+  void StoreNexe(const std::string& key,
+                 const std::string& nexe,
+                 const CompletionCallback& callback);
+
+  // Retrieve the nexe from the translation cache. (Not implemented yet.)
+  int GetNexe(const std::string& key,
+              std::string* nexe,
+              const CompletionCallback& callback);
+
+  // Return the number of entries in the cache backend.
+  int Size();
+
+ private:
+  friend class PNaClTranslationCacheWriteEntry;
+  // PNaClTranslationCacheWriteEntry should only use the
+  // WriteComplete and backend methods on PNaClTranslationCache.
+  void WriteComplete(PNaClTranslationCacheWriteEntry* entry);
+  disk_cache::Backend* backend() { return disk_cache_; }
+
+  int InitWithDiskBackend(const base::FilePath& disk_cache_dir,
+                          int cache_size,
+                          const CompletionCallback& callback);
+
+  int InitWithMemBackend(int cache_size, const CompletionCallback& callback);
+
+  int Init(net::CacheType,
+           const base::FilePath& directory,
+           int cache_size,
+           const CompletionCallback& callback);
+
+  void OnCreateBackendComplete(int rv);
+
+  disk_cache::Backend* disk_cache_;
+  CompletionCallback init_callback_;
+  bool in_memory_;
+  std::map<void*, scoped_refptr<PNaClTranslationCacheWriteEntry> >
+      write_entries_;
+
+  DISALLOW_COPY_AND_ASSIGN(PNaClTranslationCache);
+};
+
+}  // namespace pnacl_cache
+
+#endif  // CHROME_BROWSER_NACL_HOST_PNACL_TRANSLATION_CACHE_H_