Bug 453781 - Merge TableExists and IndexExists, and replace nsCString with nsCAutoString

r=sdwilsh

storage/src/mozStorageConnection.cpp

@@ -447,14 +447,25 @@ mozStorageConnection::ExecuteAsync(mozIStorageStatement ** aStatements,
     return rv;
 }
 
-NS_IMETHODIMP
-mozStorageConnection::TableExists(const nsACString& aSQLStatement, PRBool *_retval)
+nsresult
+mozStorageConnection::DatabaseElementExists(enum DatabaseElementType aElementType,
+                                            const nsACString& aElementName,
+                                            PRBool *_exists)
 {
     if (!mDBConn) return NS_ERROR_NOT_INITIALIZED;
 
-    nsCString query("SELECT name FROM sqlite_master WHERE type = 'table' AND name ='");
-    query.Append(aSQLStatement);
-    query.AppendLiteral("'");
+    nsCAutoString query("SELECT name FROM sqlite_master WHERE type = '");
+    switch (aElementType) {
+        case INDEX:
+            query.Append("index");
+            break;
+        case TABLE:
+            query.Append("table");
+            break;
+    }
+    query.Append("' AND name ='");
+    query.Append(aElementName);
+    query.Append("'");
 
     sqlite3_stmt *stmt = nsnull;
     int srv = sqlite3_prepare_v2(mDBConn, query.get(), -1, &stmt, NULL);
@@ -463,53 +474,36 @@ mozStorageConnection::TableExists(const nsACString& aSQLStatement, PRBool *_retv
         return ConvertResultCode(srv);
     }
 
-    PRBool exists = PR_FALSE;
-
     srv = sqlite3_step(stmt);
     // we just care about the return value from step
     sqlite3_finalize(stmt);
 
     if (srv == SQLITE_ROW) {
-        exists = PR_TRUE;
-    } else if (srv == SQLITE_DONE) {
-        exists = PR_FALSE;
-    } else {
-        HandleSqliteError("TableExists finalize");
-        return ConvertResultCode(srv);
+        *_exists = PR_TRUE;
+        return NS_OK;
     }
-
-    *_retval = exists;
-    return NS_OK;
-}
-
-NS_IMETHODIMP
-mozStorageConnection::IndexExists(const nsACString& aIndexName, PRBool* _retval)
-{
-    if (!mDBConn) return NS_ERROR_NOT_INITIALIZED;
-
-    nsCString query("SELECT name FROM sqlite_master WHERE type = 'index' AND name ='");
-    query.Append(aIndexName);
-    query.AppendLiteral("'");
-
-    sqlite3_stmt *stmt = nsnull;
-    int srv = sqlite3_prepare_v2(mDBConn, query.get(), -1, &stmt, NULL);
-    if (srv != SQLITE_OK) {
-        HandleSqliteError(query.get());
-        return ConvertResultCode(srv);
-    }
-
-    *_retval = PR_FALSE;
-
-    srv = sqlite3_step(stmt);
-    (void)sqlite3_finalize(stmt);
-
-    if (srv == SQLITE_ROW) {
-        *_retval = PR_TRUE;
+    if (srv == SQLITE_DONE) {
+        *_exists = PR_FALSE;
+        return NS_OK;
     }
 
     return ConvertResultCode(srv);
 }
 
+NS_IMETHODIMP
+mozStorageConnection::TableExists(const nsACString& aTableName,
+                                  PRBool *_exists)
+{
+    return DatabaseElementExists(TABLE, aTableName, _exists);
+}
+
+NS_IMETHODIMP
+mozStorageConnection::IndexExists(const nsACString& aIndexName,
+                                  PRBool* _exists)
+{
+    return DatabaseElementExists(INDEX, aIndexName, _exists);
+}
+
 
 /**
  ** Transactions

storage/src/mozStorageConnection.h

@@ -90,6 +90,31 @@ protected:
         PRBool       mFound;
     };
 
+    /**
+     * Describes a certain primitive type in the database.
+     *
+     * Possible Values Are:
+     *  INDEX - To check for the existence of an index
+     *  TABLE - To check for the existence of a table
+     */
+    enum DatabaseElementType {
+        INDEX,
+        TABLE
+    };
+
+    /**
+     * Determines if the specified primitive exists.
+     *
+     * @param aElementType
+     *        The type of element to check the existence of
+     * @param aElementName
+     *        The name of the element to check for
+     * @returns true if element exists, false otherwise
+     */
+    nsresult DatabaseElementExists(enum DatabaseElementType aElementType,
+                                   const nsACString& aElementName,
+                                   PRBool *_exists);
+
     void HandleSqliteError(const char *aSqlStatement);
     static PLDHashOperator s_FindFuncEnum(const nsACString &aKey,
                                           nsISupports* aData, void* userArg);