[sql] WARN_UNUSED_RESULT on Execute().

chrome/browser/net/sqlite_persistent_cookie_store.cc

Index: chrome/browser/net/sqlite_persistent_cookie_store.cc
diff --git a/chrome/browser/net/sqlite_persistent_cookie_store.cc b/chrome/browser/net/sqlite_persistent_cookie_store.cc
index 875b37f412ede00812dd3c904c52e06d547f7649..50ca24f337589fb8ecb9995d96852454593c0987 100644
--- a/chrome/browser/net/sqlite_persistent_cookie_store.cc
+++ b/chrome/browser/net/sqlite_persistent_cookie_store.cc
@@ -294,11 +294,13 @@ bool InitTable(sql::Connection* db) {
   }
 
   // Try to create the index every time. Older versions did not have this index,
-  // so we want those people to get it. Ignore errors, since it may exist.

[wtc, 2011/12/21 01:16:17]

shess: please confirm that you want this function to fail if
the index already exists.

Or do these db->Execute() calls succeed (but do nothing) if
the index already exists?

[Scott Hess - ex-Googler, 2011/12/21 02:41:01]

Yeah, the "CREATE INDEX IF NOT EXISTS" will succeed if the index already exists,
even if it resulted from a different create entirely, but will fail if there is
some other error while creating the index.  Such errors could include a
read-only database, table corruption, running out of disk space, etc.

I'll instrument the code and make sure this is actually happening.  I've run
stuff, everything seems to work, but that could be a false negative...

-  db->Execute("CREATE INDEX IF NOT EXISTS cookie_times ON cookies"
-              " (creation_utc)");
+  // so we want those people to get it.
+  if (!db->Execute("CREATE INDEX IF NOT EXISTS cookie_times ON cookies"
+                   " (creation_utc)"))
+    return false;
 
-  db->Execute("CREATE INDEX IF NOT EXISTS domain ON cookies(host_key)");
+  if (!db->Execute("CREATE INDEX IF NOT EXISTS domain ON cookies(host_key)"))
+    return false;
 
   return true;
 }
@@ -671,24 +673,24 @@ bool SQLitePersistentCookieStore::Backend::EnsureDatabaseVersion() {
     sql::Transaction transaction(db_.get());
     transaction.Begin();
 #if !defined(OS_WIN)
-    db_->Execute(
+    ignore_result(db_->Execute(
         "UPDATE cookies "
         "SET creation_utc = creation_utc + 11644473600000000 "
         "WHERE rowid IN "
         "(SELECT rowid FROM cookies WHERE "
-          "creation_utc > 0 AND creation_utc < 11644473600000000)");
-    db_->Execute(
+          "creation_utc > 0 AND creation_utc < 11644473600000000)"));
+    ignore_result(db_->Execute(
         "UPDATE cookies "
         "SET expires_utc = expires_utc + 11644473600000000 "
         "WHERE rowid IN "
         "(SELECT rowid FROM cookies WHERE "
-          "expires_utc > 0 AND expires_utc < 11644473600000000)");
-    db_->Execute(
+          "expires_utc > 0 AND expires_utc < 11644473600000000)"));
+    ignore_result(db_->Execute(
         "UPDATE cookies "
         "SET last_access_utc = last_access_utc + 11644473600000000 "
         "WHERE rowid IN "
         "(SELECT rowid FROM cookies WHERE "
-          "last_access_utc > 0 AND last_access_utc < 11644473600000000)");
+          "last_access_utc > 0 AND last_access_utc < 11644473600000000)"));
 #endif
     ++cur_version;
     meta_table_.SetVersionNumber(cur_version);