extensions/browser/value_store/value_store_frontend.cc

   1 // Copyright 2014 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 "extensions/browser/value_store/value_store_frontend.h"
   6
   7 #include "base/bind.h"
   8 #include "base/files/file_path.h"
   9 #include "base/logging.h"
  10 #include "base/trace_event/trace_event.h"
  11 #include "content/public/browser/browser_thread.h"
  12 #include "extensions/browser/value_store/leveldb_value_store.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_CURRENTLY_ON(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_CURRENTLY_ON(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_CURRENTLY_ON(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_CURRENTLY_ON(BrowserThread::FILE);
  57     // We don't need the old value, so skip generating changes.
  58     ValueStore::WriteResult result = storage_->Set(
  59         ValueStore::IGNORE_QUOTA | ValueStore::NO_GENERATE_CHANGES,
  60         key,
  61         *value.get());
  62     LOG_IF(ERROR, result->HasError()) << "Error while writing " << key << " to "
  63                                       << db_path_.value();
  64   }
  65
  66   void Remove(const std::string& key) {
  67     DCHECK_CURRENTLY_ON(BrowserThread::FILE);
  68     storage_->Remove(key);
  69   }
  70
  71  private:
  72   friend class base::RefCountedThreadSafe<Backend>;
  73
  74   virtual ~Backend() {
  75     if (BrowserThread::CurrentlyOn(BrowserThread::FILE)) {
  76       delete storage_;
  77     } else {
  78       BrowserThread::DeleteSoon(BrowserThread::FILE, FROM_HERE, storage_);
  79     }
  80   }
  81
  82   void RunCallback(const ValueStoreFrontend::ReadCallback& callback,
  83                    scoped_ptr<base::Value> value) {
  84     DCHECK_CURRENTLY_ON(BrowserThread::UI);
  85     callback.Run(value.Pass());
  86   }
  87
  88   // The actual ValueStore that handles persisting the data to disk. Used
  89   // exclusively on the FILE thread.
  90   ValueStore* storage_;
  91
  92   base::FilePath db_path_;
  93
  94   DISALLOW_COPY_AND_ASSIGN(Backend);
  95 };
  96
  97 ValueStoreFrontend::ValueStoreFrontend()
  98     : backend_(new Backend()) {
  99 }
 100
 101 ValueStoreFrontend::ValueStoreFrontend(const base::FilePath& db_path)
 102     : backend_(new Backend()) {
 103   Init(db_path);
 104 }
 105
 106 ValueStoreFrontend::ValueStoreFrontend(scoped_ptr<ValueStore> value_store)
 107     : backend_(new Backend()) {
 108   BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
 109       base::Bind(&ValueStoreFrontend::Backend::InitWithStore,
 110                  backend_, base::Passed(&value_store)));
 111 }
 112
 113 ValueStoreFrontend::~ValueStoreFrontend() {
 114   DCHECK(CalledOnValidThread());
 115 }
 116
 117 void ValueStoreFrontend::Init(const base::FilePath& db_path) {
 118   BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
 119       base::Bind(&ValueStoreFrontend::Backend::Init,
 120                  backend_, db_path));
 121 }
 122
 123 void ValueStoreFrontend::Get(const std::string& key,
 124                              const ReadCallback& callback) {
 125   DCHECK(CalledOnValidThread());
 126
 127   BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
 128       base::Bind(&ValueStoreFrontend::Backend::Get,
 129                  backend_, key, callback));
 130 }
 131
 132 void ValueStoreFrontend::Set(const std::string& key,
 133                              scoped_ptr<base::Value> value) {
 134   DCHECK(CalledOnValidThread());
 135
 136   BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
 137       base::Bind(&ValueStoreFrontend::Backend::Set,
 138                  backend_, key, base::Passed(&value)));
 139 }
 140
 141 void ValueStoreFrontend::Remove(const std::string& key) {
 142   DCHECK(CalledOnValidThread());
 143
 144   BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
 145       base::Bind(&ValueStoreFrontend::Backend::Remove,
 146                  backend_, key));
 147 }