chrome/browser/value_store/value_store_frontend.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/value_store/value_store_frontend.h"
   6
   7 #include "base/bind.h"
   8 #include "base/debug/trace_event.h"
   9 #include "base/files/file_path.h"
  10 #include "base/logging.h"
  11 #include "chrome/browser/value_store/leveldb_value_store.h"
  12 #include "content/public/browser/browser_thread.h"
  13
  14 using content::BrowserThread;
  15
  16 class ValueStoreFrontend::Backend : public base::RefCountedThreadSafe<Backend> {
  17  public:
  18   Backend() : storage_(NULL) {}
  19
  20   void Init(const base::FilePath& db_path) {
  21     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
  22     DCHECK(!storage_);
  23     TRACE_EVENT0("ValueStoreFrontend::Backend", "Init");
  24     db_path_ = db_path;
  25     storage_ = new LeveldbValueStore(db_path);
  26   }
  27
  28   // This variant is useful for testing (using a mock ValueStore).
  29   void InitWithStore(scoped_ptr<ValueStore> storage) {
  30     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
  31     DCHECK(!storage_);
  32     storage_ = storage.release();
  33   }
  34
  35   void Get(const std::string& key,
  36            const ValueStoreFrontend::ReadCallback& callback) {
  37     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
  38     ValueStore::ReadResult result = storage_->Get(key);
  39
  40     // Extract the value from the ReadResult and pass ownership of it to the
  41     // callback.
  42     scoped_ptr<base::Value> value;
  43     if (!result->HasError()) {
  44       result->settings().RemoveWithoutPathExpansion(key, &value);
  45     } else {
  46       LOG(WARNING) << "Reading " << key << " from " << db_path_.value()
  47                    << " failed: " << result->error().message;
  48     }
  49
  50     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
  51         base::Bind(&ValueStoreFrontend::Backend::RunCallback,
  52                    this, callback, base::Passed(&value)));
  53   }
  54
  55   void Set(const std::string& key, scoped_ptr<base::Value> value) {
  56     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
  57     // We don't need the old value, so skip generating changes.
  58     storage_->Set(ValueStore::IGNORE_QUOTA | ValueStore::NO_GENERATE_CHANGES,
  59                   key, *value.get());
  60   }
  61
  62   void Remove(const std::string& key) {
  63     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
  64     storage_->Remove(key);
  65   }
  66
  67  private:
  68   friend class base::RefCountedThreadSafe<Backend>;
  69
  70   virtual ~Backend() {
  71     if (BrowserThread::CurrentlyOn(BrowserThread::FILE)) {
  72       delete storage_;
  73     } else {
  74       BrowserThread::DeleteSoon(BrowserThread::FILE, FROM_HERE, storage_);
  75     }
  76   }
  77
  78   void RunCallback(const ValueStoreFrontend::ReadCallback& callback,
  79                    scoped_ptr<base::Value> value) {
  80     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
  81     callback.Run(value.Pass());
  82   }
  83
  84   // The actual ValueStore that handles persisting the data to disk. Used
  85   // exclusively on the FILE thread.
  86   ValueStore* storage_;
  87
  88   base::FilePath db_path_;
  89
  90   DISALLOW_COPY_AND_ASSIGN(Backend);
  91 };
  92
  93 ValueStoreFrontend::ValueStoreFrontend()
  94     : backend_(new Backend()) {
  95 }
  96
  97 ValueStoreFrontend::ValueStoreFrontend(const base::FilePath& db_path)
  98     : backend_(new Backend()) {
  99   Init(db_path);
 100 }
 101
 102 ValueStoreFrontend::ValueStoreFrontend(scoped_ptr<ValueStore> value_store)
 103     : backend_(new Backend()) {
 104   BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
 105       base::Bind(&ValueStoreFrontend::Backend::InitWithStore,
 106                  backend_, base::Passed(&value_store)));
 107 }
 108
 109 ValueStoreFrontend::~ValueStoreFrontend() {
 110   DCHECK(CalledOnValidThread());
 111 }
 112
 113 void ValueStoreFrontend::Init(const base::FilePath& db_path) {
 114   BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
 115       base::Bind(&ValueStoreFrontend::Backend::Init,
 116                  backend_, db_path));
 117 }
 118
 119 void ValueStoreFrontend::Get(const std::string& key,
 120                              const ReadCallback& callback) {
 121   DCHECK(CalledOnValidThread());
 122
 123   BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
 124       base::Bind(&ValueStoreFrontend::Backend::Get,
 125                  backend_, key, callback));
 126 }
 127
 128 void ValueStoreFrontend::Set(const std::string& key,
 129                              scoped_ptr<base::Value> value) {
 130   DCHECK(CalledOnValidThread());
 131
 132   BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
 133       base::Bind(&ValueStoreFrontend::Backend::Set,
 134                  backend_, key, base::Passed(&value)));
 135 }
 136
 137 void ValueStoreFrontend::Remove(const std::string& key) {
 138   DCHECK(CalledOnValidThread());
 139
 140   BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
 141       base::Bind(&ValueStoreFrontend::Backend::Remove,
 142                  backend_, key));
 143 }