Implement a bag of chips for sync.

sync/syncable/directory_backing_store.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 "sync/syncable/directory_backing_store.h"
 
 #include "build/build_config.h"
 
 #include <limits>
 
@@ skipping 21 matching lines @@
 
 namespace syncer {
 namespace syncable {
 
 // This just has to be big enough to hold an UPDATE or INSERT statement that
 // modifies all the columns in the entry table.
 static const string::size_type kUpdateStatementBufferSize = 2048;
 
 // Increment this version whenever updating DB tables.
 extern const int32 kCurrentDBVersion;  // Global visibility for our unittest.
-const int32 kCurrentDBVersion = 79;
+const int32 kCurrentDBVersion = 80;
 
 // Iterate over the fields of |entry| and bind each to |statement| for
 // updating.  Returns the number of args bound.
 void BindFields(const EntryKernel& entry,
                 sql::Statement* statement) {
   int index = 0;
   int i = 0;
   for (i = BEGIN_FIELDS; i < INT64_FIELDS_END; ++i) {
     statement->BindInt64(index++, entry.ref(static_cast<Int64Field>(i)));
   }
@@ skipping 141 matching lines @@
   if (!DeleteEntries(snapshot.metahandles_to_purge))
     return false;
 
   if (save_info) {
     const Directory::PersistedKernelInfo& info = snapshot.kernel_info;
     sql::Statement s1(db_->GetCachedStatement(
             SQL_FROM_HERE,
             "UPDATE share_info "
             "SET store_birthday = ?, "
             "next_id = ?, "
-            "notification_state = ?"));
+            "notification_state = ?, "
+            "bag_of_chips = ?"));
     s1.BindString(0, info.store_birthday);
     s1.BindInt64(1, info.next_id);
     s1.BindBlob(2, info.notification_state.data(),
                    info.notification_state.size());
+    s1.BindBlob(3, info.bag_of_chips.data(), info.bag_of_chips.size());
 
     if (!s1.Run())
       return false;
     DCHECK_EQ(db_->GetLastChangeCount(), 1);
 
     sql::Statement s2(db_->GetCachedStatement(
             SQL_FROM_HERE,
             "INSERT OR REPLACE "
             "INTO models (model_id, progress_marker, initial_sync_ended) "
             "VALUES (?, ?, ?)"));
@@ skipping 89 matching lines @@
     if (MigrateVersion77To78())
       version_on_disk = 78;
   }
 
   // Version 79 migration is a one-time fix for some users in a bad state.
   if (version_on_disk == 78) {
     if (MigrateVersion78To79())
       version_on_disk = 79;
   }
 
+  // Version 80 migration is adding the bag_of_chips column.
+  if (version_on_disk == 79) {
+    if (MigrateVersion79To80())
+      version_on_disk = 80;
+  }
+
   // If one of the migrations requested it, drop columns that aren't current.
   // It's only safe to do this after migrating all the way to the current
   // version.
   if (version_on_disk == kCurrentDBVersion && needs_column_refresh_) {
     if (!RefreshColumns())
       version_on_disk = 0;
   }
 
   // A final, alternative catch-all migration to simply re-sync everything.
   //
@@ skipping 60 matching lines @@
     return false;
 
   // Repeat the process for share_info.
   SafeDropTable("temp_share_info");
   if (!CreateShareInfoTable(true))
     return false;
 
   if (!db_->Execute(
           "INSERT INTO temp_share_info (id, name, store_birthday, "
           "db_create_version, db_create_time, next_id, cache_guid,"
-          "notification_state) "
+          "notification_state, bag_of_chips) "
           "SELECT id, name, store_birthday, db_create_version, "
-          "db_create_time, next_id, cache_guid, notification_state "
+          "db_create_time, next_id, cache_guid, notification_state, "
+          "bag_of_chips "
           "FROM share_info"))
     return false;
 
   SafeDropTable("share_info");
   if (!db_->Execute("ALTER TABLE temp_share_info RENAME TO share_info"))
     return false;
 
   needs_column_refresh_ = false;
   return true;
 }
@@ skipping 11 matching lines @@
     EntryKernel *kernel = UnpackEntry(&s);
     entry_bucket->insert(kernel);
   }
   return s.Succeeded();
 }
 
 bool DirectoryBackingStore::LoadInfo(Directory::KernelLoadInfo* info) {
   {
     sql::Statement s(
         db_->GetUniqueStatement(
-            "SELECT store_birthday, next_id, cache_guid, notification_state "
+            "SELECT store_birthday, next_id, cache_guid, notification_state, "
+            "bag_of_chips "
             "FROM share_info"));
     if (!s.Step())
       return false;
 
     info->kernel_info.store_birthday = s.ColumnString(0);
     info->kernel_info.next_id = s.ColumnInt64(1);
     info->cache_guid = s.ColumnString(2);
     s.ColumnBlobAsString(3, &(info->kernel_info.notification_state));
+    s.ColumnBlobAsString(4, &(info->kernel_info.bag_of_chips));
 
     // Verify there was only one row returned.
     DCHECK(!s.Step());
     DCHECK(s.Succeeded());
   }
 
   {
     sql::Statement s(
         db_->GetUniqueStatement(
             "SELECT model_id, progress_marker, initial_sync_ended "
@@ skipping 499 matching lines @@
   // Some users are stuck with a DB that causes them to reuse existing IDs.  We
   // perform this one-time fixup on all users to help the few that are stuck.
   // See crbug.com/142987 for details.
   if (!db_->Execute(
           "UPDATE share_info SET next_id = next_id - 65536")) {
     return false;
   }
   SetVersion(79);
   return true;
 }
+bool DirectoryBackingStore::MigrateVersion79To80() {
+  if (!db_->Execute(
+          "ALTER TABLE share_info ADD COLUMN bag_of_chips BLOB"))
+    return false;
+  sql::Statement update(db_->GetUniqueStatement(
+          "UPDATE share_info SET bag_of_chips = ?"));
+  // An empty message is serialized to an empty string.
+  update.BindBlob(0, NULL, 0);
+  if (!update.Run())
+    return false;
+  SetVersion(80);
+  return true;
+}
 
 bool DirectoryBackingStore::CreateTables() {
   DVLOG(1) << "First run, creating tables";
   // Create two little tables share_version and share_info
   if (!db_->Execute(
           "CREATE TABLE share_version ("
           "id VARCHAR(128) primary key, data INT)")) {
     return false;
   }
 
@@ skipping 15 matching lines @@
   {
     sql::Statement s(db_->GetUniqueStatement(
             "INSERT INTO share_info VALUES"
             "(?, "  // id
             "?, "   // name
             "?, "   // store_birthday
             "?, "   // db_create_version
             "?, "   // db_create_time
             "-2, "  // next_id
             "?, "   // cache_guid
-            "?);"));  // notification_state
+            "?, "   // notification_state
+            "?);"));  // bag_of_chips
     s.BindString(0, dir_name_);                   // id
     s.BindString(1, dir_name_);                   // name
     s.BindString(2, "");                          // store_birthday
     // TODO(akalin): Remove this unused db_create_version field. (Or
     // actually use it for something.) http://crbug.com/118356
     s.BindString(3, "Unknown");                   // db_create_version
     s.BindInt(4, static_cast<int32>(time(0)));    // db_create_time
     s.BindString(5, GenerateCacheGUID());         // cache_guid
     s.BindBlob(6, NULL, 0);                       // notification_state
-
+    s.BindBlob(7, NULL, 0);                       // bag_of_chips
     if (!s.Run())
       return false;
   }
 
   if (!CreateModelsTable())
     return false;
 
   // Create the big metas table.
   if (!CreateMetasTable(false))
     return false;
@@ skipping 55 matching lines @@
   query.append(name);
   // This is the current schema for the ShareInfo table, from version 76
   // onward.
   query.append(" ("
       "id TEXT primary key, "
       "name TEXT, "
       "store_birthday TEXT, "
       "db_create_version TEXT, "
       "db_create_time INT, "
       "next_id INT default -2, "
-      "cache_guid TEXT ");
-
-  query.append(", notification_state BLOB");
-  query.append(")");
+      "cache_guid TEXT, "
+      "notification_state BLOB, "
+      "bag_of_chips BLOB"
+      ")");
   return db_->Execute(query.c_str());
 }
 
 bool DirectoryBackingStore::CreateShareInfoTableVersion71(
     bool is_temporary) {
   const char* name = is_temporary ? "temp_share_info" : "share_info";
   string query = "CREATE TABLE ";
   query.append(name);
   // This is the schema for the ShareInfo table used from versions 71 to 72.
   query.append(" ("
@@ skipping 33 matching lines @@
     bool prev_exists = (ids_set.find(entry->ref(PREV_ID).value()) != end);
     bool parent_exists = (ids_set.find(entry->ref(PARENT_ID).value()) != end);
     bool next_exists = (ids_set.find(entry->ref(NEXT_ID).value()) != end);
     is_ok = is_ok && prev_exists && parent_exists && next_exists;
   }
   return is_ok;
 }
 
 }  // namespace syncable
 }  // namespace syncer