[sql] Static helper to delete database and all associated files.

Not all of the ad-hoc file_util::Delete() cases handle -journal, and
if -wal was added all of them need to be tracked down.

BUG=none

Review URL: https://chromiumcodereview.appspot.com/17058004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@208140 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 53 insertions, 0 deletions

diff --git a/sql/connection.cc b/sql/connection.cc
index 67cdf08..e99b6bc 100644
--- a/sql/connection.cc
+++ b/sql/connection.cc
@@ -377,6 +377,32 @@ bool Connection::RazeAndClose() {
   return result;
 }
 
+// TODO(shess): To the extent possible, figure out the optimal
+// ordering for these deletes which will prevent other connections
+// from seeing odd behavior.  For instance, it may be necessary to
+// manually lock the main database file in a SQLite-compatible fashion
+// (to prevent other processes from opening it), then delete the
+// journal files, then delete the main database file.  Another option
+// might be to lock the main database file and poison the header with
+// junk to prevent other processes from opening it successfully (like
+// Gears "SQLite poison 3" trick).
+//
+// static
+bool Connection::Delete(const base::FilePath& path) {
+  base::ThreadRestrictions::AssertIOAllowed();
+
+  base::FilePath journal_path(path.value() + FILE_PATH_LITERAL("-journal"));
+  base::FilePath wal_path(path.value() + FILE_PATH_LITERAL("-wal"));
+
+  file_util::Delete(journal_path, false);
+  file_util::Delete(wal_path, false);
+  file_util::Delete(path, false);
+
+  return !file_util::PathExists(journal_path) &&
+      !file_util::PathExists(wal_path) &&
+      !file_util::PathExists(path);
+}
+
 bool Connection::BeginTransaction() {
   if (needs_rollback_) {
     DCHECK_GT(transaction_nesting_, 0);
diff --git a/sql/connection.h b/sql/connection.h
index 91139ce..6b03849 100644
--- a/sql/connection.h
+++ b/sql/connection.h
@@ -224,6 +224,18 @@ class SQL_EXPORT Connection {
   // cases.
   bool RazeAndClose();
 
+  // Delete the underlying database files associated with |path|.
+  // This should be used on a database which has no existing
+  // connections.  If any other connections are open to the same
+  // database, this could cause odd results or corruption (for
+  // instance if a hot journal is deleted but the associated database
+  // is not).
+  //
+  // Returns true if the database file and associated journals no
+  // longer exist, false otherwise.  If the database has never
+  // existed, this will return true.
+  static bool Delete(const base::FilePath& path);
+
   // Transactions --------------------------------------------------------------
 
   // Transaction management. We maintain a virtual transaction stack to emulate
diff --git a/sql/connection_unittest.cc b/sql/connection_unittest.cc
index b43e83c..1afd2dd 100644
--- a/sql/connection_unittest.cc
+++ b/sql/connection_unittest.cc
@@ -411,3 +411,18 @@ TEST_F(SQLConnectionTest, SetTempDirForSQL) {
   ASSERT_TRUE(meta_table.Init(&db(), 4, 4));
 }
 #endif
+
+TEST_F(SQLConnectionTest, Delete) {
+  EXPECT_TRUE(db().Execute("CREATE TABLE x (x)"));
+  db().Close();
+
+  // Should have both a main database file and a journal file because
+  // of journal_mode PERSIST.
+  base::FilePath journal(db_path().value() + FILE_PATH_LITERAL("-journal"));
+  ASSERT_TRUE(file_util::PathExists(db_path()));
+  ASSERT_TRUE(file_util::PathExists(journal));
+
+  sql::Connection::Delete(db_path());
+  EXPECT_FALSE(file_util::PathExists(db_path()));
+  EXPECT_FALSE(file_util::PathExists(journal));
+}