Add last_requested field to the favicon_bitmaps table of the favicons database.

components/history/core/browser/thumbnail_database.cc

 // 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.
 
 #include "components/history/core/browser/thumbnail_database.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/bind.h"
@@ skipping 40 matching lines @@
 //                    the link tag. The FAVICON type is used for the default
 //                    favicon.ico favicon.
 //
 // favicon_bitmaps    This table contains the PNG encoded bitmap data of the
 //                    favicons. There is a separate row for every size in a
 //                    multi resolution bitmap. The bitmap data is associated
 //                    to the favicon via the |icon_id| field which matches
 //                    the |id| field in the appropriate row in the |favicons|
 //                    table.
 //
-//  id                Unique ID.
-//  icon_id           The ID of the favicon that the bitmap is associated to.
-//  last_updated      The time at which this favicon was inserted into the
+//   id               Unique ID.
+//   icon_id          The ID of the favicon that the bitmap is associated to.
+//   last_updated     The time at which this favicon was inserted into the
 //                    table. This is used to determine if it needs to be
 //                    redownloaded from the web.
-//  image_data        PNG encoded data of the favicon.
-//  width             Pixel width of |image_data|.
-//  height            Pixel height of |image_data|.
+//   last_requested   The time at which this bitmap was last requested. This is
+//                    used to determine the priority with which the bitmap
+//                    should be retained on cleanup.
+//   image_data       PNG encoded data of the favicon.
+//   width            Pixel width of |image_data|.
+//   height           Pixel height of |image_data|.
 
 namespace {
 
 // For this database, schema migrations are deprecated after two
 // years.  This means that the oldest non-deprecated version should be
 // two years old or greater (thus the migrations to get there are
 // older).  Databases containing deprecated versions will be cleared
 // at startup.  Since this database is a cache, losing old data is not
 // fatal (in fact, very old data may be expired immediately at startup
 // anyhow).
 
+// Version 8: ???????? by rogerm@chromium.org on 2015-??-??
 // Version 7: 911a634d/r209424 by qsr@chromium.org on 2013-07-01
 // Version 6: 610f923b/r152367 by pkotwicz@chromium.org on 2012-08-20
-// Version 5: e2ee8ae9/r105004 by groby@chromium.org on 2011-10-12
+// Version 5: e2ee8ae9/r105004 by groby@chromium.org on 2011-10-12 (deprecated)

[Scott Hess - ex-Googler, 2015/03/19 21:32:22]

Cool beans.  I was going to suggest that earlier, but it seemed mostly unrelated
to this CL.  Certainly fine with doing maintenance as you go, though :-).

[Roger McFarlane (Chromium), 2015/03/20 14:40:59]

With they way recovery/upgrade is done, it was messy to support 5. So, this
wasn't *only* maintenance/cleanup.

:)

 // Version 4: 5f104d76/r77288 by sky@chromium.org on 2011-03-08 (deprecated)
 // Version 3: 09911bf3/r15 by initial.commit on 2008-07-26 (deprecated)
 
 // Version number of the database.
 // NOTE(shess): When changing the version, add a new golden file for
 // the new version and a test to verify that Init() works with it.
-const int kCurrentVersionNumber = 7;
-const int kCompatibleVersionNumber = 7;
-const int kDeprecatedVersionNumber = 4;  // and earlier.
+const int kCurrentVersionNumber = 8;
+const int kCompatibleVersionNumber = 8;
+const int kDeprecatedVersionNumber = 5;  // and earlier.
 
 void FillIconMapping(const sql::Statement& statement,
                      const GURL& page_url,
                      IconMapping* icon_mapping) {
   icon_mapping->mapping_id = statement.ColumnInt64(0);
   icon_mapping->icon_id = statement.ColumnInt64(1);
   icon_mapping->icon_type =
       static_cast<favicon_base::IconType>(statement.ColumnInt(2));
   icon_mapping->icon_url = GURL(statement.ColumnString(3));
   icon_mapping->page_url = page_url;
@@ skipping 201 matching lines @@
     return false;
 
   const char kFaviconBitmapsSql[] =
       "CREATE TABLE IF NOT EXISTS favicon_bitmaps"
       "("
       "id INTEGER PRIMARY KEY,"
       "icon_id INTEGER NOT NULL,"
       "last_updated INTEGER DEFAULT 0,"
       "image_data BLOB,"
       "width INTEGER DEFAULT 0,"
-      "height INTEGER DEFAULT 0"
+      "height INTEGER DEFAULT 0,"
+      // This field is at the end so that fresh tables and migrated tables have
+      // the same layout.
+      "last_requested INTEGER DEFAULT 0"
       ")";
   if (!db->Execute(kFaviconBitmapsSql))
     return false;
 
   return true;
 }
 
 // NOTE(shess): Schema modifications must consider initial creation in
 // |InitImpl()|, recovery in |RecoverDatabaseOrRaze()|, and history pruning in
 // |RetainDataForPageUrls()|.
@@ skipping 65 matching lines @@
 // Recover the database to the extent possible, razing it if recovery
 // is not possible.
 // TODO(shess): This is mostly just a safe proof of concept.  In the
 // real world, this database is probably not worthwhile recovering, as
 // opposed to just razing it and starting over whenever corruption is
 // detected.  So this database is a good test subject.
 void RecoverDatabaseOrRaze(sql::Connection* db, const base::FilePath& db_path) {
   // NOTE(shess): This code is currently specific to the version
   // number.  I am working on simplifying things to loosen the
   // dependency, meanwhile contact me if you need to bump the version.
-  DCHECK_EQ(7, kCurrentVersionNumber);
+  DCHECK_EQ(8, kCurrentVersionNumber);
 
   // TODO(shess): Reset back after?
   db->reset_error_callback();
 
   // For histogram purposes.
   size_t favicons_rows_recovered = 0;
   size_t favicon_bitmaps_rows_recovered = 0;
   size_t icon_mapping_rows_recovered = 0;
   int64 original_size = 0;
   base::GetFileSize(db_path, &original_size);
@@ skipping 23 matching lines @@
     // way, unclear how to resolve.
     sql::Recovery::Rollback(recovery.Pass());
     RecordRecoveryEvent(RECOVERY_EVENT_FAILED_META_VERSION);
     return;
   }
 
   // This code may be able to fetch version information that the regular
   // deprecation path cannot.
   // NOTE(shess): v5 and v6 are currently not deprecated in the normal Init()
   // path, but are deprecated in the recovery path in the interest of keeping
   // the code simple.  http://crbug.com/327485 for numbers.

[pkotwicz, 2015/03/20 19:51:55]

Nit: Can you please update the comment?

[Roger McFarlane (Chromium), 2015/03/27 14:40:18]

See: https://codereview.chromium.org/1010973011

   DCHECK_LE(kDeprecatedVersionNumber, 6);
   if (version <= 6) {
     sql::Recovery::Unrecoverable(recovery.Pass());
     RecordRecoveryEvent(RECOVERY_EVENT_DEPRECATED);
     return;
   }
 
-  // Earlier versions have been handled or deprecated, later versions should be
-  // impossible.
-  if (version != 7) {
+  // Earlier versions have been handled or deprecated.
+  if (version < 7) {
     sql::Recovery::Unrecoverable(recovery.Pass());
     RecordRecoveryEvent(RECOVERY_EVENT_FAILED_META_WRONG_VERSION);
     return;
   }
 
   // Recover to current schema version.
   sql::MetaTable recover_meta_table;
   if (!recover_meta_table.Init(recovery->db(), kCurrentVersionNumber,
                                kCompatibleVersionNumber)) {
     sql::Recovery::Rollback(recovery.Pass());
@@ skipping 142 matching lines @@
     if (status == sql::INIT_OK)
       return status;
 
     meta_table_.Reset();
     db_.Close();
   }
   return status;
 }
 
 void ThumbnailDatabase::ComputeDatabaseMetrics() {
-  sql::Statement favicon_count(
-      db_.GetCachedStatement(SQL_FROM_HERE, "SELECT COUNT(*) FROM favicons"));
-  UMA_HISTOGRAM_COUNTS_10000(
-      "History.NumFaviconsInDB",
-      favicon_count.Step() ? favicon_count.ColumnInt(0) : 0);
+  // Count all icon files referenced by the DB.
+  {
+    sql::Statement favicon_count(
+        db_.GetCachedStatement(SQL_FROM_HERE, "SELECT COUNT(*) FROM favicons"));
+    UMA_HISTOGRAM_COUNTS_10000(
+        "History.NumFaviconsInDB",
+        favicon_count.Step() ? favicon_count.ColumnInt(0) : 0);
+  }
+
+  // Count all bitmap resources cached in the DB.
+  {
+    sql::Statement bitmap_count(
+        db_.GetCachedStatement(
+            SQL_FROM_HERE, "SELECT COUNT(*) FROM favicon_bitmaps"));
+    UMA_HISTOGRAM_COUNTS_10000(
+        "History.NumBitmapsInDB",
+        bitmap_count.Step() ? bitmap_count.ColumnInt(0) : 0);
+  }
 }
 
 void ThumbnailDatabase::BeginTransaction() {
   db_.BeginTransaction();
 }
 
 void ThumbnailDatabase::CommitTransaction() {
   db_.CommitTransaction();
 }
 
@@ skipping 89 matching lines @@
     *png_icon_data = data;
   }
 
   if (pixel_size) {
     *pixel_size = gfx::Size(statement.ColumnInt(2),
                             statement.ColumnInt(3));
   }
   return true;
 }
 
+bool ThumbnailDatabase::GetFaviconBitmapLastRequestedTime(
+    FaviconBitmapID bitmap_id,
+    base::Time* last_requested) {
+  DCHECK(bitmap_id);
+  DCHECK(last_requested);
+  sql::Statement statement(db_.GetCachedStatement(SQL_FROM_HERE,
+      "SELECT last_requested FROM favicon_bitmaps WHERE id=?"));
+  statement.BindInt64(0, bitmap_id);
+
+  if (!statement.Step())
+    return false;
+
+  *last_requested = base::Time::FromInternalValue(statement.ColumnInt64(0));
+  return true;
+}
+
 FaviconBitmapID ThumbnailDatabase::AddFaviconBitmap(
     favicon_base::FaviconID icon_id,
     const scoped_refptr<base::RefCountedMemory>& icon_data,
     base::Time time,
     const gfx::Size& pixel_size) {
   DCHECK(icon_id);
   sql::Statement statement(db_.GetCachedStatement(SQL_FROM_HERE,
       "INSERT INTO favicon_bitmaps (icon_id, image_data, last_updated, width, "
       "height) VALUES (?, ?, ?, ?, ?)"));
   statement.BindInt64(0, icon_id);
@@ skipping 35 matching lines @@
     FaviconBitmapID bitmap_id,
     base::Time time) {
   DCHECK(bitmap_id);
   sql::Statement statement(db_.GetCachedStatement(SQL_FROM_HERE,
       "UPDATE favicon_bitmaps SET last_updated=? WHERE id=?"));
   statement.BindInt64(0, time.ToInternalValue());
   statement.BindInt64(1, bitmap_id);
   return statement.Run();
 }
 
+bool ThumbnailDatabase::SetFaviconBitmapLastRequestedTime(
+    FaviconBitmapID bitmap_id,
+    base::Time time) {
+  DCHECK(bitmap_id);
+  sql::Statement statement(db_.GetCachedStatement(SQL_FROM_HERE,
+      "UPDATE favicon_bitmaps SET last_requested=? WHERE id=?"));
+  statement.BindInt64(0, time.ToInternalValue());
+  statement.BindInt64(1, bitmap_id);
+  return statement.Run();
+}
+
 bool ThumbnailDatabase::DeleteFaviconBitmap(FaviconBitmapID bitmap_id) {
   sql::Statement statement(db_.GetCachedStatement(SQL_FROM_HERE,
       "DELETE FROM favicon_bitmaps WHERE id=?"));
   statement.BindInt64(0, bitmap_id);
   return statement.Run();
 }
 
 bool ThumbnailDatabase::SetFaviconOutOfDate(favicon_base::FaviconID icon_id) {
   sql::Statement statement(db_.GetCachedStatement(SQL_FROM_HERE,
       "UPDATE favicon_bitmaps SET last_updated=? WHERE icon_id=?"));
@@ skipping 284 matching lines @@
   const char kRenameFaviconsTable[] =
       "ALTER TABLE favicons RENAME TO old_favicons";
   const char kCopyFavicons[] =
       "INSERT INTO favicons (id, url, icon_type) "
       "SELECT mapping.new_icon_id, old.url, old.icon_type "
       "FROM old_favicons AS old "
       "JOIN temp.icon_id_mapping AS mapping "
       "ON (old.id = mapping.old_icon_id)";
   const char kDropOldFaviconsTable[] = "DROP TABLE old_favicons";
 
+  // Note that we allow the last_requested field to be reset to the default
+  // value (0).
   const char kRenameFaviconBitmapsTable[] =
       "ALTER TABLE favicon_bitmaps RENAME TO old_favicon_bitmaps";
   const char kCopyFaviconBitmaps[] =
       "INSERT INTO favicon_bitmaps "
       "  (icon_id, last_updated, image_data, width, height) "
       "SELECT mapping.new_icon_id, old.last_updated, "
       "    old.image_data, old.width, old.height "
       "FROM old_favicon_bitmaps AS old "
       "JOIN temp.icon_id_mapping AS mapping "
       "ON (old.icon_id = mapping.old_icon_id)";
@@ skipping 87 matching lines @@
     return sql::INIT_FAILURE;
 
   // TODO(shess): Failing Begin() implies that something serious is
   // wrong with the database.  Raze() may be in order.
 
 #if defined(OS_MACOSX) && !defined(OS_IOS)
   // Exclude the thumbnails file from backups.
   base::mac::SetFileBackupExclusion(db_name);
 #endif
 
   // thumbnails table has been obsolete for a long time, remove any

[huangs, 2015/03/19 19:14:11]

NIT: unwrap?

[beaudoin, 2015/03/19 21:36:54]

I'm fine leaving it wrapped, 90% of the multi-line comments in this file could
be unwrapped. It would almost look off if this one was. :)

[Roger McFarlane (Chromium), 2015/03/20 14:41:00]

Acknowledged.

[Roger McFarlane (Chromium), 2015/03/20 14:41:00]

Done.

-  // detrious.
+  // detritus.
   ignore_result(db_.Execute("DROP TABLE IF EXISTS thumbnails"));
 
   // At some point, operations involving temporary tables weren't done
   // atomically and users have been stranded.  Drop those tables and
   // move on.
   // TODO(shess): Prove it?  Audit all cases and see if it's possible
   // that this implies non-atomic update, and should thus be handled
   // via the corruption handler.
   ignore_result(db_.Execute("DROP TABLE IF EXISTS temp_favicons"));
   ignore_result(db_.Execute("DROP TABLE IF EXISTS temp_favicon_bitmaps"));
@@ skipping 37 matching lines @@
     if (!UpgradeToVersion6())
       return CantUpgradeToVersion(cur_version);
   }
 
   if (cur_version == 6) {
     ++cur_version;
     if (!UpgradeToVersion7())
       return CantUpgradeToVersion(cur_version);
   }
 
+  if (cur_version == 7) {
+    ++cur_version;
+    if (!UpgradeToVersion8())
+      return CantUpgradeToVersion(cur_version);
+  }
+
   LOG_IF(WARNING, cur_version < kCurrentVersionNumber) <<
       "Thumbnail database version " << cur_version << " is too old to handle.";
 
   // Initialization is complete.
   if (!transaction.Commit())
     return sql::INIT_FAILURE;
 
   // Raze the database if the structure of the favicons database is not what
   // it should be. This error cannot be detected via the SQL error code because
   // the error code for running SQL statements against a database with missing
@@ skipping 60 matching lines @@
       db_.Execute("CREATE INDEX IF NOT EXISTS favicons_url ON favicons(url)");
 
   if (!success)
     return false;
 
   meta_table_.SetVersionNumber(7);
   meta_table_.SetCompatibleVersionNumber(std::min(7, kCompatibleVersionNumber));
   return true;
 }
 
+bool ThumbnailDatabase::UpgradeToVersion8() {
+  // Add the last_requested column to the favicon_bitmaps table.
+  const char kFaviconBitmapsAddLastRequestedSql[] =
+      "ALTER TABLE favicon_bitmaps ADD COLUMN last_requested INTEGER DEFAULT 0";
+  if (!db_.Execute(kFaviconBitmapsAddLastRequestedSql))
+    return false;
+
+

[huangs, 2015/03/19 19:14:11]

NIT: extra space.  I recently learned about "git cl lint", maybe try that?

[Roger McFarlane (Chromium), 2015/03/20 14:41:00]

Done.

+  meta_table_.SetVersionNumber(8);
+  meta_table_.SetCompatibleVersionNumber(std::min(8, kCompatibleVersionNumber));
+  return true;
+}
+
 bool ThumbnailDatabase::IsFaviconDBStructureIncorrect() {
   return !db_.IsSQLValid("SELECT id, url, icon_type FROM favicons");
 }
 
 }  // namespace history