Add method to delete entries from the Directory backing sqlite file by metahandle.

This isn't used anywhere yet, but I plan to as part of the work for bug 40252.

BUG=40252
TEST=DirectoryBackingStoreTest.DeleteEntries

Review URL: http://codereview.chromium.org/2817019

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@50398 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 92 insertions, 1 deletions

diff --git a/chrome/browser/sync/syncable/directory_backing_store.cc b/chrome/browser/sync/syncable/directory_backing_store.cc
index 2a29789..26bb31f 100644
--- a/chrome/browser/sync/syncable/directory_backing_store.cc
+++ b/chrome/browser/sync/syncable/directory_backing_store.cc
@@ -581,6 +581,35 @@ bool DirectoryBackingStore::DeleteExtendedAttributeFromDB(
   return true;
 }
 
+bool DirectoryBackingStore::DeleteEntries(const MetahandleSet& handles) {
+  if (handles.empty())
+    return true;
+
+  sqlite3* db_handle = NULL;
+  if (!OpenAndConfigureHandleHelper(&db_handle))
+    return false;
+
+  sqlite_utils::scoped_sqlite_db_ptr scoped_handle(db_handle);
+  string query = "DELETE FROM metas WHERE metahandle IN (";
+  for (MetahandleSet::const_iterator it = handles.begin(); it != handles.end();
+       ++it) {
+    if (it != handles.begin())
+      query.append(",");
+    query.append(Int64ToString(*it));
+  }
+  query.append(")");
+  SQLStatement statement;
+  int result = statement.prepare(scoped_handle.get(), query.data(),
+                                 query.size());
+  if (SQLITE_OK == result) {
+    result = statement.step();
+    if (SQLITE_DONE == result)
+      statement.finalize();
+  }
+
+  return SQLITE_DONE == result;
+}
+
 bool DirectoryBackingStore::DropDeletedEntries() {
   static const char delete_extended_attributes[] =
       "DELETE FROM extended_attributes WHERE metahandle IN "
diff --git a/chrome/browser/sync/syncable/directory_backing_store.h b/chrome/browser/sync/syncable/directory_backing_store.h
index 4e4ab19..b240ed7 100644
--- a/chrome/browser/sync/syncable/directory_backing_store.h
+++ b/chrome/browser/sync/syncable/directory_backing_store.h
@@ -75,6 +75,10 @@ class DirectoryBackingStore {
   // calls SaveChanges *must* be the thread that owns/destroys |this|.
   virtual bool SaveChanges(const Directory::SaveChangesSnapshot& snapshot);
 
+  // Removes each entry whose metahandle is in |handles| from the database.
+  // Does synchronous I/O.  Returns false on error.
+  bool DeleteEntries(const MetahandleSet& handles);
+
  private:
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateVersion67To68);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateVersion68To69);
@@ -82,7 +86,9 @@ class DirectoryBackingStore {
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateVersion70To71);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, ModelTypeIds);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, Corruption);
+  FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, DeleteEntries);
   FRIEND_TEST_ALL_PREFIXES(MigrationTest, ToCurrentVersion);
+  friend class MigrationTest;
 
   // General Directory initialization and load helpers.
   DirOpenResult InitializeTables();
@@ -149,7 +155,7 @@ class DirectoryBackingStore {
   int GetVersion();
   bool MigrateToSpecifics(const char* old_columns,
                           const char* specifics_column,
-                          void (*handler_function) (
+                          void(*handler_function) (
                               SQLStatement* old_value_query,
                               int old_value_column,
                               sync_pb::EntitySpecifics* mutable_new_value));
diff --git a/chrome/browser/sync/syncable/directory_backing_store_unittest.cc b/chrome/browser/sync/syncable/directory_backing_store_unittest.cc
index 777a163..971f170 100644
--- a/chrome/browser/sync/syncable/directory_backing_store_unittest.cc
+++ b/chrome/browser/sync/syncable/directory_backing_store_unittest.cc
@@ -47,6 +47,18 @@ class MigrationTest : public testing::TestWithParam<int> {
   void SetUpVersion69Database();
   void SetUpVersion70Database();
 
+  void SetUpCurrentDatabaseAndCheckVersion() {
+    SetUpVersion70Database();  // Prepopulates data.
+    scoped_ptr<DirectoryBackingStore> dbs(
+        new DirectoryBackingStore(GetUsername(), GetDatabasePath()));
+
+    dbs->BeginLoad();
+    ASSERT_EQ(OPENED, dbs->InitializeTables());
+    ASSERT_FALSE(dbs->needs_column_refresh_);
+    ASSERT_EQ(kCurrentDBVersion, dbs->GetVersion());
+    dbs->EndLoad();
+  }
+
  private:
   ScopedTempDir temp_dir_;
 };
@@ -894,4 +906,48 @@ TEST_F(DirectoryBackingStoreTest, Corruption) {
   }
 }
 
+TEST_F(DirectoryBackingStoreTest, DeleteEntries) {
+  SetUpCurrentDatabaseAndCheckVersion();
+  scoped_ptr<DirectoryBackingStore> dbs(
+      new DirectoryBackingStore(GetUsername(), GetDatabasePath()));
+  dbs->BeginLoad();
+
+  MetahandlesIndex index;
+  dbs->LoadEntries(&index);
+  size_t initial_size = index.size();
+  ASSERT_LT(0U, initial_size) << "Test requires entries to delete.";
+  int64 first_to_die = (*index.begin())->ref(META_HANDLE);
+  MetahandleSet to_delete;
+  to_delete.insert(first_to_die);
+  EXPECT_TRUE(dbs->DeleteEntries(to_delete));
+
+  index.clear();
+  dbs->LoadEntries(&index);
+
+  EXPECT_EQ(initial_size - 1, index.size());
+  bool delete_failed = false;
+  for (MetahandlesIndex::iterator it = index.begin(); it != index.end();
+       ++it) {
+    if ((*it)->ref(META_HANDLE) == first_to_die) {
+      delete_failed = true;
+      break;
+    }
+  }
+  EXPECT_FALSE(delete_failed);
+
+  to_delete.clear();
+  for (MetahandlesIndex::iterator it = index.begin(); it != index.end();
+       ++it) {
+    to_delete.insert((*it)->ref(META_HANDLE));
+  }
+
+  EXPECT_TRUE(dbs->DeleteEntries(to_delete));
+
+  index.clear();
+  dbs->LoadEntries(&index);
+  EXPECT_EQ(0U, index.size());
+
+  dbs->EndLoad();
+}
+
 }  // namespace syncable