Change ThumbnailStore to use sqlite instead of individual files try 2. Previous try failed interactive_ui_tests.

Review URL: http://codereview.chromium.org/149361

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@20272 0039d316-1c4b-4281-b951-d872f2087c98

7 files changed, 226 insertions, 279 deletions

diff --git a/chrome/browser/dom_ui/dom_ui_thumbnail_source.cc b/chrome/browser/dom_ui/dom_ui_thumbnail_source.cc
index fd40e867..5a10c7c 100644
--- a/chrome/browser/dom_ui/dom_ui_thumbnail_source.cc
+++ b/chrome/browser/dom_ui/dom_ui_thumbnail_source.cc
@@ -17,14 +17,14 @@
 
 DOMUIThumbnailSource::DOMUIThumbnailSource(Profile* profile)
     : DataSource(chrome::kChromeUIThumbnailPath, MessageLoop::current()),
-      profile_(profile),
-      store_(profile->GetThumbnailStore()) {
+      profile_(profile) {
 }
 
 void DOMUIThumbnailSource::StartDataRequest(const std::string& path,
                                             int request_id) {
   if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kThumbnailStore)) {
     RefCountedBytes* data = NULL;
+    scoped_refptr<ThumbnailStore> store_ = profile_->GetThumbnailStore();
 
     if (store_->GetPageThumbnail(GURL(path), &data)) {
       // Got the thumbnail.
diff --git a/chrome/browser/dom_ui/dom_ui_thumbnail_source.h b/chrome/browser/dom_ui/dom_ui_thumbnail_source.h
index 2d475af..c94967b 100644
--- a/chrome/browser/dom_ui/dom_ui_thumbnail_source.h
+++ b/chrome/browser/dom_ui/dom_ui_thumbnail_source.h
@@ -40,9 +40,6 @@ class DOMUIThumbnailSource : public ChromeURLDataManager::DataSource {
   Profile* profile_;
   CancelableRequestConsumerT<int, 0> cancelable_consumer_;
 
-  // The ThumbnailStore from which thumbnails are requested.
-  scoped_refptr<ThumbnailStore> store_;
-
   // Raw PNG representation of the thumbnail to show when the thumbnail
   // database doesn't have a thumbnail for a webpage.
   scoped_refptr<RefCountedBytes> default_thumbnail_;
diff --git a/chrome/browser/profile.cc b/chrome/browser/profile.cc
index 6e0a5a4..085f814 100644
--- a/chrome/browser/profile.cc
+++ b/chrome/browser/profile.cc
@@ -1016,7 +1016,7 @@ TabRestoreService* ProfileImpl::GetTabRestoreService() {
 ThumbnailStore* ProfileImpl::GetThumbnailStore() {
   if (!thumbnail_store_.get()) {
     thumbnail_store_ = new ThumbnailStore;
-    thumbnail_store_->Init(GetPath().AppendASCII("thumbnailstore"), this);
+    thumbnail_store_->Init(GetPath().AppendASCII("Top Thumbnails"), this);
   }
   return thumbnail_store_.get();
 }
diff --git a/chrome/browser/tab_contents/tab_contents.cc b/chrome/browser/tab_contents/tab_contents.cc
index b417f34..cddddfb 100644
--- a/chrome/browser/tab_contents/tab_contents.cc
+++ b/chrome/browser/tab_contents/tab_contents.cc
@@ -1878,8 +1878,8 @@ void TabContents::UpdateThumbnail(const GURL& url,
                                   const ThumbnailScore& score) {
   // Tell History about this thumbnail
   if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kThumbnailStore)) {
-    profile()->GetThumbnailStore()->
-        SetPageThumbnail(url, bitmap, score, !profile()->IsOffTheRecord());
+    if (!profile()->IsOffTheRecord())
+      profile()->GetThumbnailStore()->SetPageThumbnail(url, bitmap, score);
   } else {
     HistoryService* hs;
     if (!profile()->IsOffTheRecord() &&
diff --git a/chrome/browser/thumbnail_store.cc b/chrome/browser/thumbnail_store.cc
index d5679c9..315f12f 100644
--- a/chrome/browser/thumbnail_store.cc
+++ b/chrome/browser/thumbnail_store.cc
@@ -8,7 +8,6 @@
 #include <algorithm>
 
 #include "base/basictypes.h"
-#include "base/pickle.h"
 #include "base/file_util.h"
 #include "base/gfx/jpeg_codec.h"
 #include "base/md5.h"
@@ -18,51 +17,57 @@
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/profile.h"
 #include "chrome/common/pref_service.h"
-#include "chrome/common/thumbnail_score.h"
+#include "chrome/common/sqlite_utils.h"
 #include "googleurl/src/gurl.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 
 
 ThumbnailStore::ThumbnailStore()
     : cache_(NULL),
-      cache_initialized_(false),
+      db_(NULL),
       hs_(NULL),
       url_blacklist_(NULL) {
 }
 
 ThumbnailStore::~ThumbnailStore() {
+  CommitCacheToDB(NULL);
 }
 
-void ThumbnailStore::Init(const FilePath& file_path, Profile* profile) {
-  file_path_ = file_path;
+void ThumbnailStore::Init(const FilePath& db_name,
+                          Profile* profile) {
+  // Load thumbnails already in the database.
+  g_browser_process->file_thread()->message_loop()->PostTask(FROM_HERE,
+      NewRunnableMethod(this, &ThumbnailStore::InitializeFromDB,
+                        db_name, MessageLoop::current()));
+
+  // Take ownership of a reference to the HistoryService.
   hs_ = profile->GetHistoryService(Profile::EXPLICIT_ACCESS);
-  url_blacklist_ = profile->GetPrefs()->
-      GetMutableDictionary(prefs::kNTPMostVisitedURLsBlacklist);
 
-  g_browser_process->file_thread()->message_loop()->PostTask(FROM_HERE,
-      NewRunnableMethod(this, &ThumbnailStore::GetAllThumbnailsFromDisk,
-                        file_path_, MessageLoop::current()));
+  // Store a pointer to a persistent table of blacklisted URLs.
+  url_blacklist_ = profile->GetPrefs()->
+    GetMutableDictionary(prefs::kNTPMostVisitedURLsBlacklist);
 
+  // Get the list of most visited URLs and redirect information from the
+  // HistoryService.
   timer_.Start(base::TimeDelta::FromMinutes(30), this,
-               &ThumbnailStore::UpdateURLData);
+      &ThumbnailStore::UpdateURLData);
   UpdateURLData();
 }
 
 bool ThumbnailStore::SetPageThumbnail(const GURL& url,
                                       const SkBitmap& thumbnail,
-                                      const ThumbnailScore& score,
-                                      bool write_to_disk) {
-  if (!cache_initialized_)
+                                      const ThumbnailScore& score) {
+  if (!cache_.get())
     return false;
 
   if (!ShouldStoreThumbnailForURL(url) ||
       (cache_->find(url) != cache_->end() &&
-      !ShouldReplaceThumbnailWith((*cache_)[url].second, score)))
+      !ShouldReplaceThumbnailWith((*cache_)[url].score_, score)))
     return true;
 
   base::TimeTicks encode_start = base::TimeTicks::Now();
 
-  // Encode the SkBitmap to jpeg and add to cache.
+  // Encode the SkBitmap to jpeg.
   scoped_refptr<RefCountedBytes> jpeg_data = new RefCountedBytes;
   SkAutoLockPixels thumbnail_lock(thumbnail);
   bool encoded = JPEGCodec::Encode(
@@ -79,38 +84,31 @@ bool ThumbnailStore::SetPageThumbnail(const GURL& url,
     return false;
 
   // Update the cache_ with the new thumbnail.
-  (*cache_)[url] = std::make_pair(jpeg_data, score);
+  (*cache_)[url] = CacheEntry(jpeg_data, score, true);
 
-  // Write the new thumbnail data to disk in the background on file_thread.
-  if (write_to_disk) {
-    g_browser_process->file_thread()->message_loop()->PostTask(FROM_HERE,
-        NewRunnableMethod(this, &ThumbnailStore::WriteThumbnailToDisk, url,
-        jpeg_data, score));
-  }
   return true;
 }
 
 bool ThumbnailStore::GetPageThumbnail(
     const GURL& url,
     RefCountedBytes** data) {
-  if (!cache_initialized_ || IsURLBlacklisted(url))
+  if (!cache_.get() || IsURLBlacklisted(url))
     return false;
 
   // Look up the |url| in the redirect list to find the final destination
   // which is the key into the |cache_|.
   history::RedirectMap::iterator it = redirect_urls_->find(url);
-  if (it == redirect_urls_->end())
-    return false;
-
-  // Return the first available thumbnail starting at the end of the
-  // redirect list.
-  history::RedirectList::reverse_iterator rit;
-  for (rit = it->second->data.rbegin();
-       rit != it->second->data.rend(); ++rit) {
-    if (cache_->find(*rit) != cache_->end()) {
-      *data = (*cache_)[*rit].first;
-      (*data)->AddRef();
-      return true;
+  if (it != redirect_urls_->end()) {
+    // Return the first available thumbnail starting at the end of the
+    // redirect list.
+    history::RedirectList::reverse_iterator rit;
+    for (rit = it->second->data.rbegin();
+        rit != it->second->data.rend(); ++rit) {
+      if (cache_->find(*rit) != cache_->end()) {
+        *data = (*cache_)[*rit].data_.get();
+        (*data)->AddRef();
+        return true;
+      }
     }
   }
 
@@ -119,7 +117,7 @@ bool ThumbnailStore::GetPageThumbnail(
   if (cache_->find(url) == cache_->end())
     return false;
 
-  *data = (*cache_)[url].first;
+  *data = (*cache_)[url].data_.get();
   (*data)->AddRef();
   return true;
 }
@@ -141,14 +139,14 @@ void ThumbnailStore::OnURLDataAvailable(std::vector<GURL>* urls,
 }
 
 void ThumbnailStore::CleanCacheData() {
-  if (!cache_initialized_)
+  if (!cache_.get())
     return;
 
   // For each URL in the cache, search the RedirectMap for the originating URL.
   // If this URL is blacklisted or not in the most visited list, delete the
   // thumbnail data for it from the cache and from disk in the background.
   scoped_refptr<RefCountedVector<GURL> > old_urls = new RefCountedVector<GURL>;
-  for (ThumbnailStore::Cache::iterator cache_it = cache_->begin();
+  for (Cache::iterator cache_it = cache_->begin();
        cache_it != cache_->end();) {
     const GURL* url = NULL;
     for (history::RedirectMap::iterator it = redirect_urls_->begin();
@@ -171,145 +169,115 @@ void ThumbnailStore::CleanCacheData() {
 
   if (old_urls->data.size()) {
     g_browser_process->file_thread()->message_loop()->PostTask(FROM_HERE,
-        NewRunnableMethod(this, &ThumbnailStore::DeleteThumbnails, old_urls));
+        NewRunnableMethod(this, &ThumbnailStore::CommitCacheToDB, old_urls));
   }
 }
 
-void ThumbnailStore::DeleteThumbnails(
-    scoped_refptr<RefCountedVector<GURL> > thumbnail_urls) const {
-  for (std::vector<GURL>::iterator it = thumbnail_urls->data.begin();
-       it != thumbnail_urls->data.end(); ++it)
-    file_util::Delete(file_path_.AppendASCII(MD5String(it->spec())), false);
-}
-
-void ThumbnailStore::GetAllThumbnailsFromDisk(FilePath filepath,
-                                              MessageLoop* cb_loop) {
-  ThumbnailStore::Cache* cache = new ThumbnailStore::Cache;
+void ThumbnailStore::CommitCacheToDB(
+    scoped_refptr<RefCountedVector<GURL> > stale_urls) const {
+  if (!db_)
+    return;
 
-  // Create the specified directory if it does not exist.
-  if (!file_util::DirectoryExists(filepath)) {
-    file_util::CreateDirectory(filepath);
-  } else {
-    // Walk the directory and read the thumbnail data from disk.
-    FilePath path;
-    GURL url;
-    RefCountedBytes* data;
-    ThumbnailScore score;
-    file_util::FileEnumerator fenum(filepath, false,
-                                    file_util::FileEnumerator::FILES);
-
-    while (!(path = fenum.Next()).empty()) {
-      data = new RefCountedBytes;
-      if (GetPageThumbnailFromDisk(path, &url, data, &score))
-        (*cache)[url] = std::make_pair(data, score);
-      else
-        delete data;
+  // Delete old thumbnails.
+  if (stale_urls.get()) {
+    for (std::vector<GURL>::iterator it = stale_urls->data.begin();
+        it != stale_urls->data.end(); ++it) {
+      SQLITE_UNIQUE_STATEMENT(statement, *statement_cache_,
+          "DELETE FROM thumbnails WHERE url=?");
+      statement->bind_string(0, it->spec());
+      if (statement->step() != SQLITE_DONE)
+        NOTREACHED();
     }
   }
-  cb_loop->PostTask(FROM_HERE,
-      NewRunnableMethod(this, &ThumbnailStore::OnDiskDataAvailable, cache));
-}
 
-bool ThumbnailStore::GetPageThumbnailFromDisk(const FilePath& file,
-                                              GURL* url,
-                                              RefCountedBytes* data,
-                                              ThumbnailScore* score) const {
-  int64 file_size;
-  if (!file_util::GetFileSize(file, &file_size))
-    return false;
+  // Update cached thumbnails.
+  for (Cache::iterator it = cache_->begin(); it != cache_->end(); ++it) {
+    if (!it->second.dirty_)
+      continue;
+
+    SQLITE_UNIQUE_STATEMENT(statement, *statement_cache_,
+        "INSERT OR REPLACE INTO thumbnails "
+        "(url, boring_score, good_clipping, at_top, time_taken, data) "
+        "VALUES (?,?,?,?,?,?)");
+    statement->bind_string(0, it->first.spec());
+    statement->bind_double(1, it->second.score_.boring_score);
+    statement->bind_bool(2, it->second.score_.good_clipping);
+    statement->bind_bool(3, it->second.score_.at_top);
+    statement->bind_int64(4, it->second.score_.time_at_snapshot.
+                             ToInternalValue());
+    statement->bind_blob(5, &it->second.data_->data[0],
+                         static_cast<int>(it->second.data_->data.size()));
+    if (statement->step() != SQLITE_DONE)
+      DLOG(WARNING) << "Unable to insert thumbnail for URL";
+    else
+      it->second.dirty_ = false;
+  }
+}
 
-  // Read the file into a buffer.
-  std::vector<char> file_data;
-  file_data.resize(static_cast<unsigned int>(file_size));
-  if (file_util::ReadFile(file, &file_data[0],
-                          static_cast<int>(file_size)) == -1)
-    return false;
+void ThumbnailStore::InitializeFromDB(const FilePath& db_name,
+                                      MessageLoop* cb_loop) {
+  if (OpenSqliteDb(db_name, &db_) != SQLITE_OK)
+    return;
 
-  // Unpack the url, ThumbnailScore and JPEG size from the buffer.
-  std::string url_string;
-  unsigned int jpeg_len;
-  void* iter = NULL;
-  Pickle packed(&file_data[0], static_cast<int>(file_size));
+  // Use a large page size since the thumbnails we are storing are typically
+  // large, a small cache size since we cache in memory and don't go to disk
+  // often, and take exclusive access since nobody else uses this db.
+  sqlite3_exec(db_, "PRAGMA page_size=4096 "
+                    "PRAGMA cache_size=64 "
+                    "PRAGMA locking_mode=EXCLUSIVE", NULL, NULL, NULL);
+
+  statement_cache_ = new SqliteStatementCache;
+
+  // Use local DBCloseScoper so that if we cannot create the table and
+  // need to return, the |db_| and |statement_cache_| are closed properly.
+  history::DBCloseScoper scoper(&db_, &statement_cache_);
+
+  if (!DoesSqliteTableExist(db_, "thumbnails")) {
+    if (sqlite3_exec(db_, "CREATE TABLE thumbnails ("
+          "url LONGVARCHAR PRIMARY KEY,"
+          "boring_score DOUBLE DEFAULT 1.0,"
+          "good_clipping INTEGER DEFAULT 0,"
+          "at_top INTEGER DEFAULT 0,"
+          "time_taken INTEGER DEFAULT 0,"
+          "data BLOB)", NULL, NULL, NULL) != SQLITE_OK)
+      return;
+  }
 
-  if (!packed.ReadString(&iter, &url_string) ||
-      !UnpackScore(score, packed, iter) ||
-      !packed.ReadUInt32(&iter, &jpeg_len))
-    return false;
+  statement_cache_->set_db(db_);
 
-  // Store the url to the out parameter.
-  GURL temp_url(url_string);
-  url->Swap(&temp_url);
+  // Now we can use a DBCloseScoper at the object scope.
+  scoper.Detach();
+  close_scoper_.Attach(&db_, &statement_cache_);
 
-  // Unpack the JPEG data from the buffer.
-  const char* jpeg_data = NULL;
-  int out_len;
+  if (cb_loop)
+    GetAllThumbnailsFromDisk(cb_loop);
+}
 
-  if (!packed.ReadData(&iter, &jpeg_data, &out_len) ||
-      out_len != static_cast<int>(jpeg_len))
-    return false;
+void ThumbnailStore::GetAllThumbnailsFromDisk(MessageLoop* cb_loop) {
+  ThumbnailStore::Cache* cache = new ThumbnailStore::Cache;
 
-  // Copy jpeg data to the out parameter.
-  data->data.resize(jpeg_len);
-  memcpy(&data->data[0], jpeg_data, jpeg_len);
+  SQLITE_UNIQUE_STATEMENT(statement, *statement_cache_,
+      "SELECT * FROM thumbnails");
+
+  while (statement->step() == SQLITE_ROW) {
+    GURL url(statement->column_string(0));
+    ThumbnailScore score(statement->column_double(1),      // Boring score
+                         statement->column_bool(2),        // Good clipping
+                         statement->column_bool(3),        // At top
+                         base::Time::FromInternalValue(
+                            statement->column_int64(4)));  // Time taken
+    scoped_refptr<RefCountedBytes> data = new RefCountedBytes;
+    if (statement->column_blob_as_vector(5, &data->data))
+      (*cache)[url] = CacheEntry(data, score, false);
+  }
 
-  return true;
+  cb_loop->PostTask(FROM_HERE,
+      NewRunnableMethod(this, &ThumbnailStore::OnDiskDataAvailable, cache));
 }
 
 void ThumbnailStore::OnDiskDataAvailable(ThumbnailStore::Cache* cache) {
-  if (cache) {
+  if (cache)
     cache_.reset(cache);
-    cache_initialized_ = true;
-  }
-}
-
-bool ThumbnailStore::WriteThumbnailToDisk(const GURL& url,
-                                          scoped_refptr<RefCountedBytes> data,
-                                          const ThumbnailScore& score) const {
-  Pickle packed;
-  FilePath file = file_path_.AppendASCII(MD5String(url.spec()));
-
-  // Pack the url, ThumbnailScore, and the JPEG data.
-  packed.WriteString(url.spec());
-  PackScore(score, &packed);
-  packed.WriteUInt32(data->data.size());
-  packed.WriteData(reinterpret_cast<char*>(&data->data[0]), data->data.size());
-
-  // Write the packed data to a file.
-  file_util::Delete(file, false);
-  return file_util::WriteFile(file,
-                              reinterpret_cast<const char*>(packed.data()),
-                              packed.size()) != -1;
-}
-
-void ThumbnailStore::PackScore(const ThumbnailScore& score,
-                               Pickle* packed) const {
-  // Pack the contents of the given ThumbnailScore into the given Pickle.
-  packed->WriteData(reinterpret_cast<const char*>(&score.boring_score),
-                    sizeof(score.boring_score));
-  packed->WriteBool(score.at_top);
-  packed->WriteBool(score.good_clipping);
-  packed->WriteInt64(score.time_at_snapshot.ToInternalValue());
-}
-
-bool ThumbnailStore::UnpackScore(ThumbnailScore* score, const Pickle& packed,
-                                 void*& iter) const {
-  // Unpack a ThumbnailScore from the given Pickle and iterator.
-  const char* boring = NULL;
-  int out_len;
-  int64 us;
-
-  if (!packed.ReadData(&iter, &boring, &out_len) ||
-      !packed.ReadBool(&iter, &score->at_top) ||
-      !packed.ReadBool(&iter, &score->good_clipping) ||
-      !packed.ReadInt64(&iter, &us))
-    return false;
-
-  if (out_len != sizeof(score->boring_score))
-    return false;
-
-  memcpy(&score->boring_score, boring, sizeof(score->boring_score));
-  score->time_at_snapshot = base::Time::FromInternalValue(us);
-  return true;
 }
 
 bool ThumbnailStore::ShouldStoreThumbnailForURL(const GURL& url) const {
@@ -333,6 +301,6 @@ std::wstring ThumbnailStore::GetDictionaryKeyForURL(
 
 bool ThumbnailStore::IsPopular(const GURL& url) const {
   return most_visited_urls_->end() != find(most_visited_urls_->begin(),
-                                          most_visited_urls_->end(),
-                                          url);
+                                           most_visited_urls_->end(),
+                                           url);
 }
diff --git a/chrome/browser/thumbnail_store.h b/chrome/browser/thumbnail_store.h
index cf29e43..0ec81f4 100644
--- a/chrome/browser/thumbnail_store.h
+++ b/chrome/browser/thumbnail_store.h
@@ -15,17 +15,19 @@
 #include "base/timer.h"
 #include "chrome/browser/cancelable_request.h"
 #include "chrome/browser/history/history.h"
+#include "chrome/browser/history/url_database.h"  // For DBCloseScoper
 #include "chrome/common/pref_names.h"
 #include "chrome/common/ref_counted_util.h"
+#include "chrome/common/sqlite_compiled_statement.h"
+#include "chrome/common/thumbnail_score.h"
 #include "testing/gtest/include/gtest/gtest_prod.h"
 
 class DictionaryValue;
 class GURL;
 class HistoryService;
-class Pickle;
 class Profile;
 class SkBitmap;
-struct ThumbnailScore;
+struct sqlite3;
 namespace base {
 class Time;
 }
@@ -38,17 +40,13 @@ class ThumbnailStore : public base::RefCountedThreadSafe<ThumbnailStore> {
   ~ThumbnailStore();
 
   // Must be called after creation but before other methods are called.
-  // file_path is a directory where a new database should be created
-  // or the location of an existing databse.
-  void Init(const FilePath& file_path, Profile* profile);
+  void Init(const FilePath& db_name,      // The location of the database.
+            Profile* profile);            // To get to the HistoryService.
 
   // Stores the given thumbnail and score with the associated url in the cache.
-  // If write_to_disk is true, the thumbnail data is written to disk on the
-  // file_thread.
   bool SetPageThumbnail(const GURL& url,
                         const SkBitmap& thumbnail,
-                        const ThumbnailScore& score,
-                        bool write_to_disk);
+                        const ThumbnailScore& score);
 
   // Sets *data to point to the thumbnail for the given url.
   // Returns false if no thumbnail available.
@@ -61,9 +59,22 @@ class ThumbnailStore : public base::RefCountedThreadSafe<ThumbnailStore> {
   FRIEND_TEST(ThumbnailStoreTest, FollowRedirects);
   friend class ThumbnailStoreTest;
 
+  struct CacheEntry {
+    scoped_refptr<RefCountedBytes> data_;
+    ThumbnailScore score_;
+    bool dirty_;
+
+    CacheEntry() : data_(NULL), score_(ThumbnailScore()), dirty_(false) {}
+    CacheEntry(RefCountedBytes* data,
+               const ThumbnailScore& score,
+               bool dirty)
+        : data_(data),
+          score_(score),
+          dirty_(dirty) {}
+  };
+
   // Data structure used to store thumbnail data in memory.
-  typedef std::map<GURL, std::pair<scoped_refptr<RefCountedBytes>,
-      ThumbnailScore> > Cache;
+  typedef std::map<GURL, CacheEntry> Cache;
 
   // Most visited URLs and their redirect lists -------------------------------
 
@@ -72,8 +83,7 @@ class ThumbnailStore : public base::RefCountedThreadSafe<ThumbnailStore> {
   // callback is OnURLDataAvailable.
   void UpdateURLData();
 
-  // The callback for UpdateURLData. The ThumbnailStore takes ownership of
-  // the most visited urls list and redirect lists passed in.
+  // The callback for UpdateURLData.
   void OnURLDataAvailable(std::vector<GURL>* urls,
                           history::RedirectMap* redirects);
 
@@ -84,43 +94,26 @@ class ThumbnailStore : public base::RefCountedThreadSafe<ThumbnailStore> {
   // visited sites.
   void CleanCacheData();
 
-  // Deletes thumbnail data from disk for the given list of urls.
-  void DeleteThumbnails(
-      scoped_refptr<RefCountedVector<GURL> > thumbnail_urls) const;
-
   // Disk operations ----------------------------------------------------------
 
+  // Initialize |db_| to the database specified in |db_name|.  If |cb_loop|
+  // is non-null, calls GetAllThumbnailsFromDisk.  Done on the file_thread.
+  void InitializeFromDB(const FilePath& db_name, MessageLoop* cb_loop);
+
   // Read all thumbnail data from the specified FilePath into a Cache object.
   // Done on the file_thread and returns to OnDiskDataAvailable on the thread
   // owning the specified MessageLoop.
-  void GetAllThumbnailsFromDisk(FilePath filepath, MessageLoop* cb_loop);
-
-  // Read the thumbnail data from the given file and stores it in the
-  // out parameters GURL, SkBitmap, and ThumbnailScore.
-  bool GetPageThumbnailFromDisk(const FilePath& file,
-                                GURL* url,
-                                RefCountedBytes* data,
-                                ThumbnailScore* score) const;
+  void GetAllThumbnailsFromDisk(MessageLoop* cb_loop);
 
   // Once thumbnail data from the disk is available from the file_thread,
   // this function is invoked on the main thread.  It takes ownership of the
   // Cache* passed in and retains this Cache* for the lifetime of the object.
   void OnDiskDataAvailable(Cache* cache);
 
-  // Write thumbnail data to disk for a given url.
-  bool WriteThumbnailToDisk(const GURL& url,
-                            scoped_refptr<RefCountedBytes> data,
-                            const ThumbnailScore& score) const;
-
-
-  // Pack the given ThumbnailScore into the given Pickle.
-  void PackScore(const ThumbnailScore& score, Pickle* packed) const;
-
-  // Unpack a ThumbnailScore from a given Pickle and associated iterator.
-  // Returns false is a ThumbnailScore could not be unpacked.
-  bool UnpackScore(ThumbnailScore* score,
-                   const Pickle& packed,
-                   void*& iter) const;
+  // Delete each URL in the given vector from the DB and write all dirty
+  // cache entries to the DB.
+  void CommitCacheToDB(
+      scoped_refptr<RefCountedVector<GURL> > stale_urls) const;
 
   // Decide whether to store data ---------------------------------------------
 
@@ -139,10 +132,11 @@ class ThumbnailStore : public base::RefCountedThreadSafe<ThumbnailStore> {
 
   // The Cache maintained by the object.
   scoped_ptr<Cache> cache_;
-  bool cache_initialized_;
 
-  // The location of the thumbnail store.
-  FilePath file_path_;
+  // The database holding the thumbnails on disk.
+  sqlite3* db_;
+  SqliteStatementCache* statement_cache_;
+  history::DBCloseScoper close_scoper_;
 
   // We hold a reference to the history service to query for most visited URLs
   // and redirect information.
diff --git a/chrome/browser/thumbnail_store_unittest.cc b/chrome/browser/thumbnail_store_unittest.cc
index 72a5013..8d3cb8a 100644
--- a/chrome/browser/thumbnail_store_unittest.cc
+++ b/chrome/browser/thumbnail_store_unittest.cc
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include <string.h>
+#include <algorithm>
 #include <iostream>
 #include <vector>
 
@@ -12,12 +13,13 @@
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/gfx/jpeg_codec.h"
-#include "base/md5.h"
 #include "base/path_service.h"
 #include "base/ref_counted.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/ref_counted_util.h"
 #include "chrome/common/thumbnail_score.h"
+#include "chrome/common/sqlite_compiled_statement.h"
+#include "chrome/common/sqlite_utils.h"
 #include "chrome/tools/profiles/thumbnail-inl.h"
 #include "googleurl/src/gurl.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -30,9 +32,10 @@ inline unsigned int diff(unsigned int a, unsigned int b) {
 
 class ThumbnailStoreTest : public testing::Test {
  public:
-  ThumbnailStoreTest() : score1_(.5, true, false),
-    url1_("http://www.google.com/"), url2_("http://www.elgoog.com") {
+  ThumbnailStoreTest() : score_(.5, true, false),
+                         url_("http://www.google.com/") {
   }
+
   ~ThumbnailStoreTest() {
   }
 
@@ -40,33 +43,32 @@ class ThumbnailStoreTest : public testing::Test {
   void SetUp();
 
   void TearDown() {
-    file_util::Delete(file_path_.AppendASCII(url1_.host()), false);
-    file_util::Delete(file_path_.AppendASCII(url2_.host()), false);
+    file_util::Delete(db_name_, false);
   }
 
   // Compute the max difference over all pixels for each RGBA component.
   void PrintPixelDiff(SkBitmap* image_a, SkBitmap* image_b);
 
   // The directory where ThumbnailStore will store data.
-  FilePath file_path_;
+  FilePath db_name_;
 
   scoped_refptr<ThumbnailStore> store_;
   scoped_ptr<SkBitmap> google_;
   scoped_ptr<SkBitmap> weewar_;
   scoped_refptr<RefCountedBytes> jpeg_google_;
   scoped_refptr<RefCountedBytes> jpeg_weewar_;
-  ThumbnailScore score1_;
-  GURL url1_, url2_;
+  ThumbnailScore score_;
+  GURL url_;
   base::Time time_;
 };
 
 void ThumbnailStoreTest::SetUp() {
-  if (!file_util::GetTempDir(&file_path_))
+  if (!file_util::GetTempDir(&db_name_))
     FAIL();
 
   // Delete any old thumbnail files if they exist.
-  file_util::Delete(file_path_.AppendASCII(url1_.host()), false);
-  file_util::Delete(file_path_.AppendASCII(url2_.host()), false);
+  db_name_ = db_name_.AppendASCII("ThumbnailDB");
+  file_util::Delete(db_name_, false);
 
   google_.reset(JPEGCodec::Decode(kGoogleThumbnail, sizeof(kGoogleThumbnail)));
   weewar_.reset(JPEGCodec::Decode(kWeewarThumbnail, sizeof(kWeewarThumbnail)));
@@ -90,12 +92,12 @@ void ThumbnailStoreTest::SetUp() {
       &(jpeg_weewar_->data));
 
   store_ = new ThumbnailStore;
-  store_->cache_initialized_ = true;
-  store_->file_path_ = file_path_;
-  store_->most_visited_urls_.reset(new std::vector<GURL>);
-  store_->most_visited_urls_->push_back(url1_);
+
   store_->cache_.reset(new ThumbnailStore::Cache);
   store_->redirect_urls_.reset(new history::RedirectMap);
+
+  store_->most_visited_urls_.reset(new std::vector<GURL>);
+  store_->most_visited_urls_->push_back(url_);
 }
 
 void ThumbnailStoreTest::PrintPixelDiff(SkBitmap* image_a, SkBitmap* image_b) {
@@ -139,21 +141,14 @@ void ThumbnailStoreTest::PrintPixelDiff(SkBitmap* image_a, SkBitmap* image_b) {
 TEST_F(ThumbnailStoreTest, UpdateThumbnail) {
   RefCountedBytes* read_image = NULL;
   ThumbnailScore score2(0.1, true, true);
-  store_->cache_->clear();
-  store_->redirect_urls_->clear();
 
   // store_ google_ with a low score, then weewar_ with a higher score
   // and check that weewar_ overwrote google_.
 
-  EXPECT_TRUE(store_->SetPageThumbnail(url1_, *google_, score1_, false));
-  EXPECT_TRUE(store_->SetPageThumbnail(url1_, *weewar_, score2, false));
-
-  // Set fake redirects list.
-  scoped_ptr<std::vector<GURL> > redirects(new std::vector<GURL>);
-  redirects->push_back(url1_);
-  (*store_->redirect_urls_)[url1_] = new RefCountedVector<GURL>(*redirects);
+  EXPECT_TRUE(store_->SetPageThumbnail(url_, *google_, score_));
+  EXPECT_TRUE(store_->SetPageThumbnail(url_, *weewar_, score2));
 
-  EXPECT_TRUE(store_->GetPageThumbnail(url1_, &read_image));
+  EXPECT_TRUE(store_->GetPageThumbnail(url_, &read_image));
   EXPECT_EQ(read_image->data.size(), jpeg_weewar_->data.size());
   EXPECT_EQ(0, memcmp(&read_image->data[0], &jpeg_weewar_->data[0],
                       jpeg_weewar_->data.size()));
@@ -163,24 +158,16 @@ TEST_F(ThumbnailStoreTest, UpdateThumbnail) {
 
 TEST_F(ThumbnailStoreTest, RetrieveFromCache) {
   RefCountedBytes* read_image = NULL;
-  store_->cache_->clear();
-  store_->redirect_urls_->clear();
 
   // Retrieve a thumbnail/score for a page not in the cache.
 
-  EXPECT_FALSE(store_->GetPageThumbnail(url2_, &read_image));
-
-  // store_ a thumbnail into the cache and retrieve it.
+  EXPECT_FALSE(store_->GetPageThumbnail(GURL("nonexistent"), &read_image));
 
-  EXPECT_TRUE(store_->SetPageThumbnail(url1_, *google_, score1_, false));
+  // Store a thumbnail into the cache and retrieve it.
 
-  // Set fake redirects list.
-  scoped_ptr<std::vector<GURL> > redirects(new std::vector<GURL>);
-  redirects->push_back(url1_);
-  (*store_->redirect_urls_)[url1_] = new RefCountedVector<GURL>(*redirects);
-
-  EXPECT_TRUE(store_->GetPageThumbnail(url1_, &read_image));
-  EXPECT_TRUE(score1_.Equals((*store_->cache_)[url1_].second));
+  EXPECT_TRUE(store_->SetPageThumbnail(url_, *google_, score_));
+  EXPECT_TRUE(store_->GetPageThumbnail(url_, &read_image));
+  EXPECT_TRUE(score_.Equals((*store_->cache_)[url_].score_));
   EXPECT_TRUE(read_image->data.size() == jpeg_google_->data.size());
   EXPECT_EQ(0, memcmp(&read_image->data[0], &jpeg_google_->data[0],
                       jpeg_google_->data.size()));
@@ -189,46 +176,47 @@ TEST_F(ThumbnailStoreTest, RetrieveFromCache) {
 }
 
 TEST_F(ThumbnailStoreTest, RetrieveFromDisk) {
-  scoped_refptr<RefCountedBytes> read_image = new RefCountedBytes;
-  ThumbnailScore score2;
-  store_->cache_->clear();
-  store_->redirect_urls_->clear();
-
-  // store_ a thumbnail onto the disk and retrieve it.
-
-  EXPECT_TRUE(store_->SetPageThumbnail(url1_, *google_, score1_, false));
-  EXPECT_TRUE(store_->WriteThumbnailToDisk(url1_, jpeg_google_, score1_));
-  EXPECT_TRUE(store_->GetPageThumbnailFromDisk(file_path_.AppendASCII(
-      MD5String(url1_.spec())), &url2_, read_image, &score2));
-  EXPECT_TRUE(url1_ == url2_);
-  EXPECT_TRUE(score1_.Equals(score2));
-  EXPECT_TRUE(read_image->data.size() == jpeg_google_->data.size());
-  EXPECT_EQ(0, memcmp(&read_image->data[0], &jpeg_google_->data[0],
+  EXPECT_TRUE(store_->SetPageThumbnail(url_, *google_, score_));
+
+  // Write the thumbnail to disk and retrieve it.
+
+  store_->InitializeFromDB(db_name_, NULL);
+  store_->CommitCacheToDB(NULL);  // Write to the DB (dirty bit sould be set)
+  store_->cache_->clear();        // Clear it from the cache.
+
+  // Read from the DB.
+  SQLITE_UNIQUE_STATEMENT(statement, *store_->statement_cache_,
+      "SELECT * FROM thumbnails");
+  EXPECT_TRUE(statement->step() == SQLITE_ROW);
+  GURL url(statement->column_string(0));
+  ThumbnailScore score(statement->column_double(1),
+                       statement->column_bool(2),
+                       statement->column_bool(3),
+                       base::Time::FromInternalValue(
+                          statement->column_int64(4)));
+  scoped_refptr<RefCountedBytes> data = new RefCountedBytes;
+  EXPECT_TRUE(statement->column_blob_as_vector(5, &data->data));
+
+  EXPECT_TRUE(url == url_);
+  EXPECT_TRUE(score.Equals(score_));
+  EXPECT_TRUE(data->data.size() == jpeg_google_->data.size());
+  EXPECT_EQ(0, memcmp(&data->data[0], &jpeg_google_->data[0],
                       jpeg_google_->data.size()));
 }
 
 TEST_F(ThumbnailStoreTest, FollowRedirects) {
   RefCountedBytes* read_image = NULL;
-  scoped_ptr<std::vector<GURL> > redirects(new std::vector<GURL>);
-  store_->cache_->clear();
-  store_->redirect_urls_->clear();
+  std::vector<GURL> redirects;
 
   GURL my_url("google");
-  redirects->push_back(GURL("google.com"));
-  redirects->push_back(GURL("www.google.com"));
-  redirects->push_back(url1_);  // url1_ = http://www.google.com/
+  redirects.push_back(GURL("google.com"));
+  redirects.push_back(GURL("www.google.com"));
+  redirects.push_back(url_);  // url_ = http://www.google.com/
+  (*store_->redirect_urls_)[my_url] = new RefCountedVector<GURL>(redirects);
 
   store_->most_visited_urls_->push_back(my_url);
 
-  (*store_->redirect_urls_)[my_url] = new RefCountedVector<GURL>(*redirects);
-  EXPECT_TRUE(store_->SetPageThumbnail(url1_, *google_, score1_, false));
-  EXPECT_TRUE(store_->GetPageThumbnail(my_url, &read_image));
-
-  read_image->Release();
-  store_->cache_->erase(store_->cache_->find(url1_));
-
-  EXPECT_TRUE(store_->SetPageThumbnail(GURL("google.com"), *google_, score1_,
-      false));
+  EXPECT_TRUE(store_->SetPageThumbnail(GURL("google.com"), *google_, score_));
   EXPECT_TRUE(store_->GetPageThumbnail(my_url, &read_image));
 
   read_image->Release();