Adding last_forced column to thumbnails database.

The last_forced column will eventually make it possible for TopSites to indicate URLs for which thumbnails must be captured. Such URLs can come from an external source of NTP suggestions. Keeping the time makes it possible to evict forced thumbnails in a LRU fashion.

BUG=

Review URL: https://codereview.chromium.org/39053005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@231648 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 150 insertions, 69 deletions

diff --git a/chrome/browser/history/top_sites_database.cc b/chrome/browser/history/top_sites_database.cc
index 5c1939f..db9156d 100644
--- a/chrome/browser/history/top_sites_database.cc
+++ b/chrome/browser/history/top_sites_database.cc
@@ -9,19 +9,44 @@
 #include "chrome/browser/history/history_types.h"
 #include "chrome/browser/history/top_sites.h"
 #include "chrome/browser/history/top_sites_database.h"
+#include "chrome/common/thumbnail_score.h"
 #include "sql/connection.h"
 #include "sql/transaction.h"
 
+// Description of database table:
+//
+// thumbnails
+//   url              URL of the sites for which we have a thumbnail.
+//   url_rank         Index of the URL in that thumbnail, 0-based. The thumbnail
+//                    with the highest rank will be the next one evicted. Forced
+//                    thumbnails have a rank of -1.
+//   title            The title to display under that thumbnail.
+//   redirects        A space separated list of URLs that are known to redirect
+//                    to this url.
+//   boring_score     How "boring" that thumbnail is. See ThumbnailScore.
+//   good_clipping    True if the thumbnail was clipped from the bottom, keeping
+//                    the entire width of the window. See ThumbnailScore.
+//   at_top           True if the thumbnail was captured at the top of the
+//                    website.
+//   last_updated     The time at which this thumbnail was last updated.
+//   load_completed   True if the thumbnail was captured after the page load was
+//                    completed.
+//   last_forced      If this is a forced thumbnail, records the last time it
+//                    was forced. If it's not a forced thumbnail, 0.
+
 namespace history {
 
+// TODO(beaudoin): Fill revision/date details of Version 3 after landing.
+// Version 3:  by beaudoin@chromium.org
 // Version 2: eb0b24e6/r87284 by satorux@chromium.org on 2011-05-31
 // Version 1: 809cc4d8/r64072 by sky@chromium.org on 2010-10-27
 
 // From the version 1 to 2, one column was added. Old versions of Chrome
-// should be able to read version 2 files just fine.
+// should be able to read version 2 files just fine. Same thing for version 2
+// to 3.
 // 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.
-static const int kVersionNumber = 2;
+static const int kVersionNumber = 3;
 
 TopSitesDatabase::TopSitesDatabase() {
 }
@@ -69,6 +94,13 @@ bool TopSitesDatabase::Init(const base::FilePath& db_name) {
     }
   }
 
+  if (meta_table_.GetVersionNumber() == 2) {
+    if (!UpgradeToVersion3()) {
+      LOG(WARNING) << "Unable to upgrade top sites database to version 3.";
+      return false;
+    }
+  }
+
   // Version check.
   if (meta_table_.GetVersionNumber() != kVersionNumber)
     return false;
@@ -84,15 +116,16 @@ bool TopSitesDatabase::InitThumbnailTable() {
   if (!db_->DoesTableExist("thumbnails")) {
     if (!db_->Execute("CREATE TABLE thumbnails ("
                       "url LONGVARCHAR PRIMARY KEY,"
-                      "url_rank INTEGER ,"
+                      "url_rank INTEGER,"
                       "title LONGVARCHAR,"
                       "thumbnail BLOB,"
                       "redirects LONGVARCHAR,"
-                      "boring_score DOUBLE DEFAULT 1.0, "
-                      "good_clipping INTEGER DEFAULT 0, "
-                      "at_top INTEGER DEFAULT 0, "
-                      "last_updated INTEGER DEFAULT 0, "
-                      "load_completed INTEGER DEFAULT 0) ")) {
+                      "boring_score DOUBLE DEFAULT 1.0,"
+                      "good_clipping INTEGER DEFAULT 0,"
+                      "at_top INTEGER DEFAULT 0,"
+                      "last_updated INTEGER DEFAULT 0,"
+                      "load_completed INTEGER DEFAULT 0,"
+                      "last_forced INTEGER DEFAULT 0)")) {
       LOG(WARNING) << db_->GetErrorMessage();
       return false;
     }
@@ -111,13 +144,24 @@ bool TopSitesDatabase::UpgradeToVersion2() {
   return true;
 }
 
+bool TopSitesDatabase::UpgradeToVersion3() {
+  // Add 'last_forced' column.
+  if (!db_->Execute(
+          "ALTER TABLE thumbnails ADD last_forced INTEGER DEFAULT 0")) {
+    NOTREACHED();
+    return false;
+  }
+  meta_table_.SetVersionNumber(3);
+  return true;
+}
+
 void TopSitesDatabase::GetPageThumbnails(MostVisitedURLList* urls,
                                          URLToImagesMap* thumbnails) {
   sql::Statement statement(db_->GetCachedStatement(
       SQL_FROM_HERE,
       "SELECT url, url_rank, title, thumbnail, redirects, "
-      "boring_score, good_clipping, at_top, last_updated, load_completed "
-      "FROM thumbnails ORDER BY url_rank "));
+      "boring_score, good_clipping, at_top, last_updated, load_completed, "
+      "last_forced FROM thumbnails ORDER BY url_rank, last_forced"));
 
   if (!statement.is_valid()) {
     LOG(WARNING) << db_->GetErrorMessage();
@@ -128,11 +172,14 @@ void TopSitesDatabase::GetPageThumbnails(MostVisitedURLList* urls,
   thumbnails->clear();
 
   while (statement.Step()) {
-    // Results are sorted by url_rank.
+    // Results are sorted by url_rank. For forced thumbnails with url_rank = -1,
+    // thumbnails are sorted by last_forced.
     MostVisitedURL url;
     GURL gurl(statement.ColumnString(0));
     url.url = gurl;
     url.title = statement.ColumnString16(2);
+    url.last_forced_time =
+        base::Time::FromInternalValue(statement.ColumnInt64(10));
     std::string redirects = statement.ColumnString(4);
     SetRedirects(redirects, &url);
     urls->push_back(url);
@@ -148,7 +195,6 @@ void TopSitesDatabase::GetPageThumbnails(MostVisitedURLList* urls,
     thumbnail.thumbnail_score.time_at_snapshot =
         base::Time::FromInternalValue(statement.ColumnInt64(8));
     thumbnail.thumbnail_score.load_completed = statement.ColumnBool(9);
-
     (*thumbnails)[gurl] = thumbnail;
   }
 }
@@ -171,13 +217,13 @@ void TopSitesDatabase::SetRedirects(const std::string& redirects,
 }
 
 void TopSitesDatabase::SetPageThumbnail(const MostVisitedURL& url,
-                                            int new_rank,
-                                            const Images& thumbnail) {
+                                        int new_rank,
+                                        const Images& thumbnail) {
   sql::Transaction transaction(db_.get());
   transaction.Begin();
 
   int rank = GetURLRank(url);
-  if (rank == -1) {
+  if (rank == kRankOfNonExistingURL) {
     AddPageThumbnail(url, new_rank, thumbnail);
   } else {
     UpdatePageRankNoTransaction(url, new_rank);
@@ -194,7 +240,7 @@ bool TopSitesDatabase::UpdatePageThumbnail(
       "UPDATE thumbnails SET "
       "title = ?, thumbnail = ?, redirects = ?, "
       "boring_score = ?, good_clipping = ?, at_top = ?, last_updated = ?, "
-      "load_completed = ? "
+      "load_completed = ?, last_forced = ?"
       "WHERE url = ? "));
   statement.BindString16(0, url.title);
   if (thumbnail.thumbnail.get() && thumbnail.thumbnail->front()) {
@@ -208,24 +254,23 @@ bool TopSitesDatabase::UpdatePageThumbnail(
   statement.BindBool(5, score.at_top);
   statement.BindInt64(6, score.time_at_snapshot.ToInternalValue());
   statement.BindBool(7, score.load_completed);
-  statement.BindString(8, url.url.spec());
+  statement.BindInt64(8, url.last_forced_time.ToInternalValue());
+  statement.BindString(9, url.url.spec());
 
   return statement.Run();
 }
 
 void TopSitesDatabase::AddPageThumbnail(const MostVisitedURL& url,
-                                            int new_rank,
-                                            const Images& thumbnail) {
-  int count = GetRowCount();
-
+                                        int new_rank,
+                                        const Images& thumbnail) {
   sql::Statement statement(db_->GetCachedStatement(
       SQL_FROM_HERE,
       "INSERT OR REPLACE INTO thumbnails "
       "(url, url_rank, title, thumbnail, redirects, "
-      "boring_score, good_clipping, at_top, last_updated, load_completed) "
-      "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)"));
+      "boring_score, good_clipping, at_top, last_updated, load_completed, "
+      "last_forced) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)"));
   statement.BindString(0, url.url.spec());
-  statement.BindInt(1, count);  // Make it the last url.
+  statement.BindInt(1, kRankOfForcedURL);  // Fist make it a forced thumbnail.
   statement.BindString16(2, url.title);
   if (thumbnail.thumbnail.get() && thumbnail.thumbnail->front()) {
     statement.BindBlob(3, thumbnail.thumbnail->front(),
@@ -238,14 +283,25 @@ void TopSitesDatabase::AddPageThumbnail(const MostVisitedURL& url,
   statement.BindBool(7, score.at_top);
   statement.BindInt64(8, score.time_at_snapshot.ToInternalValue());
   statement.BindBool(9, score.load_completed);
+  int64 last_forced = url.last_forced_time.ToInternalValue();
+  DCHECK((last_forced == 0) == (new_rank != kRankOfForcedURL))
+      << "Thumbnail without a forced time stamp has a forced rank, or the "
+      << "opposite.";
+  statement.BindInt64(10, last_forced);
   if (!statement.Run())
     return;
 
-  UpdatePageRankNoTransaction(url, new_rank);
+  // Update rank if this is not a forced thumbnail.
+  if (new_rank != kRankOfForcedURL)
+    UpdatePageRankNoTransaction(url, new_rank);
 }
 
 void TopSitesDatabase::UpdatePageRank(const MostVisitedURL& url,
-                                          int new_rank) {
+                                      int new_rank) {
+  DCHECK((url.last_forced_time.ToInternalValue() == 0) ==
+         (new_rank != kRankOfForcedURL))
+      << "Thumbnail without a forced time stamp has a forced rank, or the "
+      << "opposite.";
   sql::Transaction transaction(db_.get());
   transaction.Begin();
   UpdatePageRankNoTransaction(url, new_rank);
@@ -256,43 +312,76 @@ void TopSitesDatabase::UpdatePageRank(const MostVisitedURL& url,
 void TopSitesDatabase::UpdatePageRankNoTransaction(
     const MostVisitedURL& url, int new_rank) {
   DCHECK_GT(db_->transaction_nesting(), 0);
+
   int prev_rank = GetURLRank(url);
-  if (prev_rank == -1) {
+  if (prev_rank == kRankOfNonExistingURL) {
     LOG(WARNING) << "Updating rank of an unknown URL: " << url.url.spec();
     return;
   }
 
   // Shift the ranks.
   if (prev_rank > new_rank) {
-    // Shift up
-    sql::Statement shift_statement(db_->GetCachedStatement(
-        SQL_FROM_HERE,
-        "UPDATE thumbnails "
-        "SET url_rank = url_rank + 1 "
-        "WHERE url_rank >= ? AND url_rank < ?"));
-    shift_statement.BindInt(0, new_rank);
-    shift_statement.BindInt(1, prev_rank);
-    shift_statement.Run();
+    if (new_rank == kRankOfForcedURL) {
+      // From non-forced to forced, shift down.
+      // Example: 2 -> -1
+      // -1, -1, -1, 0, 1, [2 -> -1], [3 -> 2], [4 -> 3]
+      sql::Statement shift_statement(db_->GetCachedStatement(
+          SQL_FROM_HERE,
+          "UPDATE thumbnails "
+          "SET url_rank = url_rank - 1 "
+          "WHERE url_rank > ?"));
+      shift_statement.BindInt(0, prev_rank);
+      shift_statement.Run();
+    } else {
+      // From non-forced to non-forced, shift up.
+      // Example: 3 -> 1
+      // -1, -1, -1, 0, [1 -> 2], [2 -> 3], [3 -> 1], 4
+      sql::Statement shift_statement(db_->GetCachedStatement(
+          SQL_FROM_HERE,
+          "UPDATE thumbnails "
+          "SET url_rank = url_rank + 1 "
+          "WHERE url_rank >= ? AND url_rank < ?"));
+      shift_statement.BindInt(0, new_rank);
+      shift_statement.BindInt(1, prev_rank);
+      shift_statement.Run();
+    }
   } else if (prev_rank < new_rank) {
-    // Shift down
-    sql::Statement shift_statement(db_->GetCachedStatement(
-        SQL_FROM_HERE,
-        "UPDATE thumbnails "
-        "SET url_rank = url_rank - 1 "
-        "WHERE url_rank > ? AND url_rank <= ?"));
-    shift_statement.BindInt(0, prev_rank);
-    shift_statement.BindInt(1, new_rank);
-    shift_statement.Run();
+    if (prev_rank == kRankOfForcedURL) {
+      // From non-forced to forced, shift up.
+      // Example: -1 -> 2
+      // -1, [-1 -> 2], -1, 0, 1, [2 -> 3], [3 -> 4], [4 -> 5]
+      sql::Statement shift_statement(db_->GetCachedStatement(
+          SQL_FROM_HERE,
+          "UPDATE thumbnails "
+          "SET url_rank = url_rank + 1 "
+          "WHERE url_rank >= ?"));
+      shift_statement.BindInt(0, new_rank);
+      shift_statement.Run();
+    } else {
+      // From non-forced to non-forced, shift down.
+      // Example: 1 -> 3.
+      // -1, -1, -1, 0, [1 -> 3], [2 -> 1], [3 -> 2], 4
+      sql::Statement shift_statement(db_->GetCachedStatement(
+          SQL_FROM_HERE,
+          "UPDATE thumbnails "
+          "SET url_rank = url_rank - 1 "
+          "WHERE url_rank > ? AND url_rank <= ?"));
+      shift_statement.BindInt(0, prev_rank);
+      shift_statement.BindInt(1, new_rank);
+      shift_statement.Run();
+    }
   }
 
-  // Set the url's rank.
+  // Set the url's rank and last_forced, since the latter changes when a URL
+  // goes from forced to non-forced and vice-versa.
   sql::Statement set_statement(db_->GetCachedStatement(
       SQL_FROM_HERE,
       "UPDATE thumbnails "
-      "SET url_rank = ? "
+      "SET url_rank = ?, last_forced = ? "
       "WHERE url == ?"));
   set_statement.BindInt(0, new_rank);
-  set_statement.BindString(1, url.url.spec());
+  set_statement.BindInt64(1, url.last_forced_time.ToInternalValue());
+  set_statement.BindString(2, url.url.spec());
   set_statement.Run();
 }
 
@@ -317,16 +406,6 @@ bool TopSitesDatabase::GetPageThumbnail(const GURL& url,
   return true;
 }
 
-int TopSitesDatabase::GetRowCount() {
-  sql::Statement select_statement(db_->GetCachedStatement(
-      SQL_FROM_HERE,
-      "SELECT COUNT (url) FROM thumbnails"));
-  if (select_statement.Step())
-    return select_statement.ColumnInt(0);
-
-  return 0;
-}
-
 int TopSitesDatabase::GetURLRank(const MostVisitedURL& url) {
   sql::Statement select_statement(db_->GetCachedStatement(
       SQL_FROM_HERE,
@@ -336,27 +415,29 @@ int TopSitesDatabase::GetURLRank(const MostVisitedURL& url) {
   if (select_statement.Step())
     return select_statement.ColumnInt(0);
 
-  return -1;
+  return kRankOfNonExistingURL;
 }
 
 // Remove the record for this URL. Returns true iff removed successfully.
 bool TopSitesDatabase::RemoveURL(const MostVisitedURL& url) {
   int old_rank = GetURLRank(url);
-  if (old_rank < 0)
+  if (old_rank == kRankOfNonExistingURL)
     return false;
 
   sql::Transaction transaction(db_.get());
   transaction.Begin();
-  // Decrement all following ranks.
-  sql::Statement shift_statement(db_->GetCachedStatement(
-      SQL_FROM_HERE,
-      "UPDATE thumbnails "
-      "SET url_rank = url_rank - 1 "
-      "WHERE url_rank > ?"));
-  shift_statement.BindInt(0, old_rank);
+  if (old_rank != kRankOfForcedURL) {
+    // Decrement all following ranks.
+    sql::Statement shift_statement(db_->GetCachedStatement(
+        SQL_FROM_HERE,
+        "UPDATE thumbnails "
+        "SET url_rank = url_rank - 1 "
+        "WHERE url_rank > ?"));
+    shift_statement.BindInt(0, old_rank);
 
-  if (!shift_statement.Run())
-    return false;
+    if (!shift_statement.Run())
+      return false;
+  }
 
   sql::Statement delete_statement(
       db_->GetCachedStatement(SQL_FROM_HERE,