Bug 386366 - Add convenience method for getting the database schema version, patch by Shawn Wilsher <sdwilsh@mozilla.com>, r=sspitzer

storage/public/mozIStorageConnection.idl

@@ -22,6 +22,7 @@
  * Contributor(s):
  *   Vladimir Vukicevic <vladimir.vukicevic@oracle.com>
  *   Brett Wilson <brettw@gmail.com>
+ *   Shawn Wilsher <me@shawnwilsher.com>
  *
  * Alternatively, the contents of this file may be used under the terms of
  * either the GNU General Public License Version 2 or later (the "GPL"), or
@@ -50,7 +51,7 @@ interface nsIFile;
  * creating prepared statements, executing SQL, and examining database
  * errors.
  */
-[scriptable, uuid(77015f88-bfc2-4669-b1c3-cc19fb07cd4e)]
+[scriptable, uuid(0b3d9b17-6c07-4c39-9ee6-314f9fbc56a6)]
 interface mozIStorageConnection : nsISupports {
   /*
    * Initialization and status
@@ -84,6 +85,12 @@ interface mozIStorageConnection : nsISupports {
    */
   readonly attribute AUTF8String lastErrorString;
 
+  /**
+   * The schema version of the database.  This should not be used until the 
+   * database is ready.  The schema will be reported as zero if it is not set.
+   */
+  attribute long schemaVersion;
+
   /*
    * Statement creation
    */

storage/src/mozStorageConnection.cpp

@@ -217,6 +217,35 @@ mozStorageConnection::GetLastErrorString(nsACString& aLastErrorString)
     return NS_OK;
 }
 
+NS_IMETHODIMP
+mozStorageConnection::GetSchemaVersion(PRInt32 *version)
+{
+    NS_ASSERTION(mDBConn, "Connection not initialized");
+
+    nsCOMPtr<mozIStorageStatement> stmt;
+    nsresult rv = CreateStatement(NS_LITERAL_CSTRING(
+        "PRAGMA user_version"), getter_AddRefs(stmt));
+    if (NS_FAILED(rv)) return rv;
+
+    *version = 0;
+    PRBool hasResult;
+    if (NS_SUCCEEDED(stmt->ExecuteStep(&hasResult)) && hasResult)
+        *version = stmt->AsInt32(0);
+
+    return NS_OK;
+}
+
+NS_IMETHODIMP
+mozStorageConnection::SetSchemaVersion(PRInt32 aVersion)
+{
+    NS_ASSERTION(mDBConn, "Connection not initialized");
+    
+    nsCAutoString stmt(NS_LITERAL_CSTRING("PRAGMA user_version = "));
+    stmt.AppendInt(aVersion);
+
+    return ExecuteSimpleSQL(stmt);
+}
+
 /**
  ** Statements & Queries
  **/

storage/test/unit/test_storage_connection.js

@@ -142,13 +142,44 @@ function test_rollbackTransaction_no_transaction()
   }
 }
 
+function test_get_schemaVersion_not_set()
+{
+  do_check_eq(0, getOpenedDatabase().schemaVersion);
+}
+
+function test_set_schemaVersion()
+{
+  var msc = getOpenedDatabase();
+  const version = 1;
+  msc.schemaVersion = version;
+  do_check_eq(version, msc.schemaVersion);
+}
+
+function test_set_schemaVersion_same()
+{
+  var msc = getOpenedDatabase();
+  const version = 1;
+  msc.schemaVersion = version; // should still work ok
+  do_check_eq(version, msc.schemaVersion);
+}
+
+function test_set_schemaVersion_negative()
+{
+  var msc = getOpenedDatabase();
+  const version = -1;
+  msc.schemaVersion = version;
+  do_check_eq(version, msc.schemaVersion);
+}
+
 var tests = [test_connectionReady, test_databaseFile,
              test_tableExists_not_created, test_indexExists_not_created,
              test_createTable_not_created, test_indexExists_created,
              test_createTable_already_created, test_lastInsertRowID,
              test_transactionInProgress_no, test_transactionInProgress_yes,
              test_commitTransaction_no_transaction,
-             test_rollbackTransaction_no_transaction];
+             test_rollbackTransaction_no_transaction,
+             test_get_schemaVersion_not_set, test_set_schemaVersion,
+             test_set_schemaVersion_same, test_set_schemaVersion_negative];
 
 function run_test()
 {