ladybird/Userland/Services/SQLServer/SQLStatement.h
Timothy Flynn 1205d39fc3 LibSQL+SQLServer: Inform SQLServer when the client has processed results
The architecture of SQLServer is currently such that it sends results
over IPC one row at a time. After the rows are exhausted, it sends a
completion IPC. However, it does not wait for the client to finish
processing a row before sending another row or the completion signal.

This can result in clients hanging if the completion comes in while a
row is being processed. At least in the case of WebView::Database, the
result is that the completion signal is dropped, and the browser then
hangs forever waiting for that signal (after it finishes processing the
row).

This patch makes SQLServer asynchronously wait for the client to tell it
that the row has been processed and the next row (or completion) may be
sent. We repurpose the `m_ongoing_executions` in SQLStatement for this
purpose (this member was oddly being written to, but otherwise unused).
2024-01-10 23:26:40 +01:00

51 lines
1.5 KiB
C++

/*
* Copyright (c) 2021, Jan de Visser <jan@de-visser.net>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/NonnullRefPtr.h>
#include <AK/RefCounted.h>
#include <AK/Vector.h>
#include <LibSQL/AST/AST.h>
#include <LibSQL/Result.h>
#include <LibSQL/ResultSet.h>
#include <LibSQL/Type.h>
#include <SQLServer/DatabaseConnection.h>
#include <SQLServer/Forward.h>
namespace SQLServer {
class SQLStatement final : public RefCounted<SQLStatement> {
public:
static SQL::ResultOr<NonnullRefPtr<SQLStatement>> create(DatabaseConnection&, StringView sql);
static RefPtr<SQLStatement> statement_for(SQL::StatementID statement_id);
SQL::StatementID statement_id() const { return m_statement_id; }
DatabaseConnection& connection() { return m_connection; }
Optional<SQL::ExecutionID> execute(Vector<SQL::Value> placeholder_values);
void ready_for_next_result(SQL::ExecutionID);
private:
SQLStatement(DatabaseConnection&, NonnullRefPtr<SQL::AST::Statement> statement);
bool should_send_result_rows(SQL::ResultSet const& result) const;
void report_error(SQL::Result, SQL::ExecutionID execution_id);
DatabaseConnection& m_connection;
SQL::StatementID m_statement_id { 0 };
struct Execution {
SQL::ResultSet result;
size_t result_size { 0 };
};
HashMap<SQL::ExecutionID, Execution> m_ongoing_executions;
SQL::ExecutionID m_next_execution_id { 0 };
NonnullRefPtr<SQL::AST::Statement> m_statement;
};
}