[sql] WARN_UNUSED_RESULT on Execute().

Goal is to encourage callers to handle errors, especially in cases
like schema changes, where dropped errors can result in broken
databases.

Many CREATE INDEX calls where ignoring errors rather than checking if
the index already existed before creating it.  Recoded those to CREATE
INDEX IF NOT EXISTS, which is for exactly this purpose.

BUG=none
TEST=none


Review URL: http://codereview.chromium.org/9005036

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@115725 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 11 insertions, 5 deletions

diff --git a/sql/connection.h b/sql/connection.h
index 39b999b..9b81804b 100644
--- a/sql/connection.h
+++ b/sql/connection.h
@@ -11,6 +11,7 @@
 #include <string>
 
 #include "base/basictypes.h"
+#include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "base/time.h"
 #include "sql/sql_export.h"
@@ -149,12 +150,12 @@ class SQL_EXPORT Connection {
 
   // Initializes the SQL connection for the given file, returning true if the
   // file could be opened. You can call this or OpenInMemory.
-  bool Open(const FilePath& path);
+  bool Open(const FilePath& path) WARN_UNUSED_RESULT;
 
   // Initializes the SQL connection for a temporary in-memory database. There
   // will be no associated file on disk, and the initial database will be
   // empty. You can call this or Open.
-  bool OpenInMemory();
+  bool OpenInMemory() WARN_UNUSED_RESULT;
 
   // Returns trie if the database has been successfully opened.
   bool is_open() const { return !!db_; }
@@ -204,11 +205,15 @@ class SQL_EXPORT Connection {
   // Executes the given SQL string, returning true on success. This is
   // normally used for simple, 1-off statements that don't take any bound
   // parameters and don't return any data (e.g. CREATE TABLE).
+  //
   // This will DCHECK if the |sql| contains errors.
-  bool Execute(const char* sql);
+  //
+  // Do not use ignore_result() to ignore all errors.  Use
+  // ExecuteAndReturnErrorCode() and ignore only specific errors.
+  bool Execute(const char* sql) WARN_UNUSED_RESULT;
 
   // Like Execute(), but returns the error code given by SQLite.
-  int ExecuteAndReturnErrorCode(const char* sql);
+  int ExecuteAndReturnErrorCode(const char* sql) WARN_UNUSED_RESULT;
 
   // Returns true if we have a statement with the given identifier already
   // cached. This is normally not necessary to call, but can be useful if the
@@ -360,7 +365,8 @@ class SQL_EXPORT Connection {
   int OnSqliteError(int err, Statement* stmt);
 
   // Like |Execute()|, but retries if the database is locked.
-  bool ExecuteWithTimeout(const char* sql, base::TimeDelta ms_timeout);
+  bool ExecuteWithTimeout(const char* sql, base::TimeDelta ms_timeout)
+      WARN_UNUSED_RESULT;
 
   // The actual sqlite database. Will be NULL before Init has been called or if
   // Init resulted in an error.