Removes some dead database code

chrome/browser/history/visitsegment_database.cc

Index: chrome/browser/history/visitsegment_database.cc
diff --git a/chrome/browser/history/visitsegment_database.cc b/chrome/browser/history/visitsegment_database.cc
index 667c9a9370c5b1ca38be11df2c0eba27c31178db..10bd357e6d9016a08cee8e547cf77b17c362fbdb 100644
--- a/chrome/browser/history/visitsegment_database.cc
+++ b/chrome/browser/history/visitsegment_database.cc
@@ -10,13 +10,11 @@
 #include <string>
 #include <vector>
 
-#include "base/command_line.h"
 #include "base/logging.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/history/page_usage_data.h"
-#include "chrome/common/chrome_switches.h"
 #include "sql/statement.h"
 #include "sql/transaction.h"
 
@@ -33,19 +31,10 @@
 //   time_slot          time stamp identifying for what day this entry is about
 //   visit_count        Number of visit in the segment
 //
-// segment_duration

[sky, 2013/12/18 00:13:59]

This was only ever used if you explicitly turned on the flag, so I'm inclined
not to bother attempting to drop the table. Let me know if you feel otherwise.

-//   id                 Primary key
-//   segment_id         Corresponding segment id
-//   time_slot          time stamp identifying what day this entry is for
-//   duration           Total time during the time_slot the user has been on
-//                      the page. This is a serialized TimeDelta value.
-// segment_duration is only created if chrome::kTrackActiveVisitTime is set.
 
 namespace history {
 
-VisitSegmentDatabase::VisitSegmentDatabase()
-    : has_duration_table_(CommandLine::ForCurrentProcess()->HasSwitch(
-                              switches::kTrackActiveVisitTime)) {
+VisitSegmentDatabase::VisitSegmentDatabase() {
 }
 
 VisitSegmentDatabase::~VisitSegmentDatabase() {
@@ -94,34 +83,13 @@ bool VisitSegmentDatabase::InitSegmentTables() {
                        "ON segment_usage(segment_id)"))
     return false;
 
-  // TODO(sky): if we decide to keep this feature duration should be added to
-  // segument_usage.
-  if (has_duration_table_ && !GetDB().DoesTableExist("segment_duration")) {
-    if (!GetDB().Execute("CREATE TABLE segment_duration ("
-                         "id INTEGER PRIMARY KEY,"
-                         "segment_id INTEGER NOT NULL,"
-                         "time_slot INTEGER NOT NULL,"
-                         "duration INTEGER DEFAULT 0 NOT NULL)")) {
-      return false;
-    }
-    if (!GetDB().Execute(
-            "CREATE INDEX segment_duration_time_slot_segment_id ON "
-            "segment_duration(time_slot, segment_id)")) {
-      return false;
-    }
-  } else if (!has_duration_table_ &&
-             !GetDB().Execute("DROP TABLE IF EXISTS segment_duration")) {
-    return false;
-  }
-
   return true;
 }
 
 bool VisitSegmentDatabase::DropSegmentTables() {
   // Dropping the tables will implicitly delete the indices.
   return GetDB().Execute("DROP TABLE segments") &&
-         GetDB().Execute("DROP TABLE segment_usage") &&
-         GetDB().Execute("DROP TABLE IF EXISTS segment_duration");
+         GetDB().Execute("DROP TABLE segment_usage");
 }
 
 // Note: the segment name is derived from the URL but is not a URL. It is
@@ -155,11 +123,6 @@ std::string VisitSegmentDatabase::ComputeSegmentName(const GURL& url) {
   return url.ReplaceComponents(r).spec();
 }
 
-// static
-base::Time VisitSegmentDatabase::SegmentTime(base::Time time) {
-  return time.LocalMidnight();
-}
-
 SegmentID VisitSegmentDatabase::GetSegmentNamed(
     const std::string& segment_name) {
   sql::Statement statement(GetDB().GetCachedStatement(SQL_FROM_HERE,
@@ -206,7 +169,7 @@ SegmentID VisitSegmentDatabase::CreateSegment(URLID url_id,
 bool VisitSegmentDatabase::IncreaseSegmentVisitCount(SegmentID segment_id,
                                                      base::Time ts,
                                                      int amount) {
-  base::Time t = SegmentTime(ts);
+  base::Time t = ts.LocalMidnight();
 
   sql::Statement select(GetDB().GetCachedStatement(SQL_FROM_HERE,
       "SELECT id, visit_count FROM segment_usage "
@@ -239,7 +202,12 @@ bool VisitSegmentDatabase::IncreaseSegmentVisitCount(SegmentID segment_id,
 void VisitSegmentDatabase::QuerySegmentUsage(
     base::Time from_time,
     int max_result_count,
-    std::vector<PageUsageData*>* result) {
+    std::vector<PageUsageData*>* results) {
+  // This function gathers the highest-ranked segments in two queries.
+  // The first gathers scores for all segments.
+  // The second gathers segment data (url, title, etc.) for the highest-ranked
+  // segments.
+
   // Gather all the segment scores.
   sql::Statement statement(GetDB().GetCachedStatement(SQL_FROM_HERE,
       "SELECT segment_id, time_slot, visit_count "
@@ -248,211 +216,53 @@ void VisitSegmentDatabase::QuerySegmentUsage(
   if (!statement.is_valid())
     return;
 
-  QuerySegmentsCommon(&statement, from_time, max_result_count,
-                      QUERY_VISIT_COUNT, result);
-}
-
-bool VisitSegmentDatabase::DeleteSegmentData(base::Time older_than) {
-  sql::Statement statement(GetDB().GetCachedStatement(SQL_FROM_HERE,
-      "DELETE FROM segment_usage WHERE time_slot < ?"));
-  statement.BindInt64(0, SegmentTime(older_than).ToInternalValue());
-
-  if (!statement.Run())
-    return false;
-
-  if (!has_duration_table_)
-    return true;
-
-  sql::Statement duration_statement(GetDB().GetCachedStatement(SQL_FROM_HERE,
-      "DELETE FROM segment_duration WHERE time_slot < ?"));
-  duration_statement.BindInt64(0, SegmentTime(older_than).ToInternalValue());
-
-  return duration_statement.Run();
-}
-
-bool VisitSegmentDatabase::DeleteSegmentForURL(URLID url_id) {
-  sql::Statement delete_usage(GetDB().GetCachedStatement(SQL_FROM_HERE,
-      "DELETE FROM segment_usage WHERE segment_id IN "
-      "(SELECT id FROM segments WHERE url_id = ?)"));
-  delete_usage.BindInt64(0, url_id);
-
-  if (!delete_usage.Run())
-    return false;
-
-  if (has_duration_table_) {
-    sql::Statement delete_duration(GetDB().GetCachedStatement(SQL_FROM_HERE,
-        "DELETE FROM segment_duration WHERE segment_id IN "
-        "(SELECT id FROM segments WHERE url_id = ?)"));
-    delete_duration.BindInt64(0, url_id);
-
-    if (!delete_duration.Run())
-      return false;
-  }
-
-  sql::Statement delete_seg(GetDB().GetCachedStatement(SQL_FROM_HERE,
-      "DELETE FROM segments WHERE url_id = ?"));
-  delete_seg.BindInt64(0, url_id);
-
-  return delete_seg.Run();
-}
-
-SegmentDurationID VisitSegmentDatabase::CreateSegmentDuration(
-    SegmentID segment_id,
-    base::Time time,
-    base::TimeDelta delta) {
-  if (!has_duration_table_)
-    return 0;
-
-  sql::Statement statement(GetDB().GetCachedStatement(SQL_FROM_HERE,
-      "INSERT INTO segment_duration (segment_id, time_slot, duration) "
-      "VALUES (?,?,?)"));
-  statement.BindInt64(0, segment_id);
-  statement.BindInt64(1, SegmentTime(time).ToInternalValue());
-  statement.BindInt64(2, delta.ToInternalValue());
-  return statement.Run() ? GetDB().GetLastInsertRowId() : 0;
-}
-
-bool VisitSegmentDatabase::SetSegmentDuration(SegmentDurationID duration_id,
-                                              base::TimeDelta time_delta) {
-  if (!has_duration_table_)
-    return false;
-
-  sql::Statement statement(GetDB().GetCachedStatement(SQL_FROM_HERE,
-      "UPDATE segment_duration SET duration = ? WHERE id = ?"));
-  statement.BindInt64(0, time_delta.ToInternalValue());
-  statement.BindInt64(1, duration_id);
-  return statement.Run();
-}
-
-bool VisitSegmentDatabase::GetSegmentDuration(SegmentID segment_id,
-                                              base::Time time,
-                                              SegmentDurationID* duration_id,
-                                              base::TimeDelta* time_delta) {
-  if (!has_duration_table_)
-    return false;
-
-  sql::Statement statement(GetDB().GetCachedStatement(SQL_FROM_HERE,
-      "SELECT id, duration FROM segment_duration "
-      "WHERE segment_id = ? AND time_slot = ? "));
-  if (!statement.is_valid())
-    return false;
-
-  statement.BindInt64(0, segment_id);
-  statement.BindInt64(1, SegmentTime(time).ToInternalValue());
-
-  if (!statement.Step())
-    return false;
-
-  *duration_id = statement.ColumnInt64(0);
-  *time_delta = base::TimeDelta::FromInternalValue(statement.ColumnInt64(1));
-  return true;
-}
-
-void VisitSegmentDatabase::QuerySegmentDuration(
-    base::Time from_time,
-    int max_result_count,
-    std::vector<PageUsageData*>* result) {
-  if (!has_duration_table_)
-    return;
-
-  // Gather all the segment scores.
-  sql::Statement statement(GetDB().GetCachedStatement(SQL_FROM_HERE,
-      "SELECT segment_id, time_slot, duration "
-      "FROM segment_duration WHERE time_slot >= ? "
-      "ORDER BY segment_id"));
-  if (!statement.is_valid())
-    return;
-
-  QuerySegmentsCommon(&statement, from_time, max_result_count, QUERY_DURATION,
-                      result);
-}
-
-bool VisitSegmentDatabase::MigratePresentationIndex() {
-  sql::Transaction transaction(&GetDB());
-  return transaction.Begin() &&
-      GetDB().Execute("DROP TABLE presentation") &&
-      GetDB().Execute("CREATE TABLE segments_tmp ("
-                      "id INTEGER PRIMARY KEY,"
-                      "name VARCHAR,"
-                      "url_id INTEGER NON NULL)") &&
-      GetDB().Execute("INSERT INTO segments_tmp SELECT "
-                      "id, name, url_id FROM segments") &&
-      GetDB().Execute("DROP TABLE segments") &&
-      GetDB().Execute("ALTER TABLE segments_tmp RENAME TO segments") &&
-      transaction.Commit();
-}
-
-
-void VisitSegmentDatabase::QuerySegmentsCommon(
-    sql::Statement* statement,
-    base::Time from_time,
-    int max_result_count,
-    QueryType query_type,
-    std::vector<PageUsageData*>* result) {
-  // This function gathers the highest-ranked segments in two queries.
-  // The first gathers scores for all segments.
-  // The second gathers segment data (url, title, etc.) for the highest-ranked
-  // segments.
-
-  base::Time ts = SegmentTime(from_time);
-  statement->BindInt64(0, ts.ToInternalValue());
+  base::Time ts = from_time.LocalMidnight();
+  statement.BindInt64(0, ts.ToInternalValue());
 
   base::Time now = base::Time::Now();
   SegmentID last_segment_id = 0;
   PageUsageData* pud = NULL;
   float score = 0;
-  base::TimeDelta duration;
-  while (statement->Step()) {
-    SegmentID segment_id = statement->ColumnInt64(0);
+  while (statement.Step()) {
+    SegmentID segment_id = statement.ColumnInt64(0);
     if (segment_id != last_segment_id) {
       if (pud) {
         pud->SetScore(score);
-        pud->SetDuration(duration);
-        result->push_back(pud);
+        results->push_back(pud);
       }
 
       pud = new PageUsageData(segment_id);
       score = 0;
       last_segment_id = segment_id;
-      duration = base::TimeDelta();
     }
 
     base::Time timeslot =
-        base::Time::FromInternalValue(statement->ColumnInt64(1));
-    int count;
-    if (query_type == QUERY_VISIT_COUNT) {
-      count = statement->ColumnInt(2);
-    } else {
-      base::TimeDelta current_duration(
-          base::TimeDelta::FromInternalValue(statement->ColumnInt64(2)));
-      duration += current_duration;
-      // Souldn't overflow since we group by day.
-      count = static_cast<int>(current_duration.InSeconds());
-    }
-    float day_score = 1.0f + log(static_cast<float>(count));
+        base::Time::FromInternalValue(statement.ColumnInt64(1));
+    int visit_count = statement.ColumnInt(2);
+    int days_ago = (now - timeslot).InDays();
 
+    // Score for this day in isolation.
+    float day_visits_score = 1.0f + log(static_cast<float>(visit_count));
     // Recent visits count more than historical ones, so we multiply in a boost
     // related to how long ago this day was.
     // This boost is a curve that smoothly goes through these values:
     // Today gets 3x, a week ago 2x, three weeks ago 1.5x, falling off to 1x
     // at the limit of how far we reach into the past.
-    int days_ago = (now - timeslot).InDays();
     float recency_boost = 1.0f + (2.0f * (1.0f / (1.0f + days_ago/7.0f)));
-    score += recency_boost * day_score;
+    score += recency_boost * day_visits_score;
   }
 
   if (pud) {
     pud->SetScore(score);
-    pud->SetDuration(duration);
-    result->push_back(pud);
+    results->push_back(pud);
   }
 
   // Limit to the top kResultCount results.
-  std::sort(result->begin(), result->end(), PageUsageData::Predicate);
-  if (static_cast<int>(result->size()) > max_result_count) {
-    STLDeleteContainerPointers(result->begin() + max_result_count,
-                               result->end());
-    result->resize(max_result_count);
+  std::sort(results->begin(), results->end(), PageUsageData::Predicate);
+  if (static_cast<int>(results->size()) > max_result_count) {
+    STLDeleteContainerPointers(results->begin() + max_result_count,
+                               results->end());
+    results->resize(max_result_count);
   }
 
   // Now fetch the details about the entries we care about.
@@ -464,8 +274,8 @@ void VisitSegmentDatabase::QuerySegmentsCommon(
   if (!statement2.is_valid())
     return;
 
-  for (size_t i = 0; i < result->size(); ++i) {
-    PageUsageData* pud = (*result)[i];
+  for (size_t i = 0; i < results->size(); ++i) {
+    PageUsageData* pud = (*results)[i];
     statement2.BindInt64(0, pud->GetID());
     if (statement2.Step()) {
       pud->SetURL(GURL(statement2.ColumnString(0)));
@@ -475,4 +285,43 @@ void VisitSegmentDatabase::QuerySegmentsCommon(
   }
 }
 
+bool VisitSegmentDatabase::DeleteSegmentData(base::Time older_than) {
+  sql::Statement statement(GetDB().GetCachedStatement(SQL_FROM_HERE,
+      "DELETE FROM segment_usage WHERE time_slot < ?"));
+  statement.BindInt64(0, older_than.LocalMidnight().ToInternalValue());
+
+  return statement.Run();
+}
+
+bool VisitSegmentDatabase::DeleteSegmentForURL(URLID url_id) {
+  sql::Statement delete_usage(GetDB().GetCachedStatement(SQL_FROM_HERE,
+      "DELETE FROM segment_usage WHERE segment_id IN "
+      "(SELECT id FROM segments WHERE url_id = ?)"));
+  delete_usage.BindInt64(0, url_id);
+
+  if (!delete_usage.Run())
+    return false;
+
+  sql::Statement delete_seg(GetDB().GetCachedStatement(SQL_FROM_HERE,
+      "DELETE FROM segments WHERE url_id = ?"));
+  delete_seg.BindInt64(0, url_id);
+
+  return delete_seg.Run();
+}
+
+bool VisitSegmentDatabase::MigratePresentationIndex() {
+  sql::Transaction transaction(&GetDB());
+  return transaction.Begin() &&
+      GetDB().Execute("DROP TABLE presentation") &&
+      GetDB().Execute("CREATE TABLE segments_tmp ("
+                      "id INTEGER PRIMARY KEY,"
+                      "name VARCHAR,"
+                      "url_id INTEGER NON NULL)") &&
+      GetDB().Execute("INSERT INTO segments_tmp SELECT "
+                      "id, name, url_id FROM segments") &&
+      GetDB().Execute("DROP TABLE segments") &&
+      GetDB().Execute("ALTER TABLE segments_tmp RENAME TO segments") &&
+      transaction.Commit();
+}
+
 }  // namespace history