mudlet/test/functional_tests/InsertTextCapTest.cpp

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fix: cap the length of inserted text like echoed text (#9497) #### Brief overview of PR changes/additions `TBuffer::insertInLine()` - the code path behind the Lua `insertText`/`cinsertText` API - now enforces the same `MAX_CHARACTERS_PER_ECHO` (1,000,000) per-echo character cap that the normal echo/print path (`appendLine()`) already applies. It also now splices the inserted run into the line in a single operation instead of one character at a time. #### Motivation for adding to Mudlet Two problems with the old code: 1. **Uncapped insert.** The echo/append path truncates a single echo to `MAX_CHARACTERS_PER_ECHO`, but `insertInLine()` did not. A single `insertText()` with a very large string was therefore unbounded, growing a line without limit (unnecessary memory pressure / potential DoS). The fix caps the inserted text to the same limit with the same truncate-in-place semantics, so oversized inserts are now bounded consistently across both paths. 2. **Quadratic insert.** The old code inserted characters one at a time into the middle of a `QString` and a `std::deque<TChar>`; each mid-container insert is O(n), making a large insert O(n^2). The run is now inserted in one operation (`QString::insert` + `std::deque::insert` with a count), producing byte-for-byte identical buffer contents. #### Other info (issues closed, discussion etc) Adds a functional test `InsertTextCapTest` (ephemeral stub port) that inserts an oversized string mid-line via `insertText()` and asserts the inserted run is capped to the limit, plus a control that a normal-sized insert is spliced in unchanged at the cursor (verifying placement and that the character/styling containers stay in sync). Verified fail-first against baseline. The broader TBuffer/display functional suite (`TelnetTextDisplayedTest`, `MainConsoleSelectionTest`, `TOscTest`, `TriggerEditorTest`, `TFeedTriggersRecursionTest`) passes. Assisted-by: Claude:claude-opus-4-8
2026-07-30 15:52:22 +02:00
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#include <QtTest/QtTest>
#include "Host.h"
#include "MudletInstanceCoordinator.h"
#include "TMainConsole.h"
#include "TelnetServerStub.h"
#include "ctelnet.h"
#include "dlgConnectionProfiles.h"
#include "mudlet.h"
extern void qInitResources_mudlet();
extern void qInitResources_qm();
extern void qInitResources_additional_splash_screens();
extern void qInitResources_mudlet_fonts_common();
extern void qInitResources_mudlet_fonts_posix();
void initializeQRCResources();
// Regression test: a single insertText() into the middle of an existing line
// (the TBuffer::insertInLine() path) must apply the same per-echo character
// cap that the echo/append path enforces, so an oversized insert cannot grow a
// line without bound.
class InsertTextCapTest : public QObject
{
Q_OBJECT
// Reference the production constant directly to avoid drift.
static constexpr int kMaxCharactersPerEcho = TBuffer::MAX_CHARACTERS_PER_ECHO;
private:
TelnetServerStub* mpServer = nullptr;
const QString mpHostname = "Test-InsertCap";
QString mpPort; // assigned the stub's actual ephemeral port in init()
const QString mpLocalhost = "localhost";
private slots:
void initTestCase() { initializeQRCResources(); }
void init()
{
mpServer = new TelnetServerStub(qApp);
mpServer->start(mpLocalhost, 0); // ephemeral OS-assigned port avoids collisions across concurrent test runs
mpPort = QString::number(mpServer->serverPort());
mudlet::start();
mudlet::self()->setupConfig();
mudlet::self()->takeOwnershipOfInstanceCoordinator(std::make_unique<MudletInstanceCoordinator>("MudletInstanceCoordinator"));
mudlet::self()->init();
mudlet::self()->setStorePasswordsSecurely(false);
deleteProfileDirectory(mpHostname);
}
// Inserting an over-long string into the middle of a line must cap the
// inserted run at kMaxCharactersPerEcho, matching the echo/append path.
void test_oversizedInsertIsCapped()
{
mpServer->setWelcomeMessage(QStringLiteral("HELLO\r\n"));
startProfile(mpHostname, mpLocalhost, mpPort);
QVERIFY2(waitForTextInBuffer(QStringLiteral("HELLO")), "Welcome text never reached the buffer");
auto console = mudlet::self()->getActiveHost()->mpConsole;
// Position the user cursor in the middle of the "HELLO" line so that
// insertText() routes through insertInLine() rather than the (already
// capped) append path used when the cursor sits at the buffer end.
QVERIFY2(console->moveCursor(2, 0), "Could not position the user cursor mid-line");
const int originalLength = console->buffer.line(0).size();
QVERIFY2(originalLength > 2, "Unexpected welcome line contents");
const int overshoot = 500;
const QString oversized(kMaxCharactersPerEcho + overshoot, QLatin1Char('Z'));
console->insertText(oversized);
const int newLength = console->buffer.line(0).size();
const int insertedLength = newLength - originalLength;
// Without the cap the full oversized string is inserted, so the inserted
// run would be kMaxCharactersPerEcho + overshoot. With the cap it is
// exactly kMaxCharactersPerEcho.
QCOMPARE(insertedLength, kMaxCharactersPerEcho);
// The character (lineBuffer) and styling (TChar deque) containers are
// filled by two separate inserts that must stay the same length, or the
// renderer reads past the end of one of them.
QCOMPARE(static_cast<int>(console->buffer.buffer.at(0).size()), newLength);
}
// A normally-sized insert must be inserted in full (guards against the cap
// being applied too aggressively).
void test_normalInsertIsUntouched()
{
mpServer->setWelcomeMessage(QStringLiteral("HELLO\r\n"));
startProfile(mpHostname, mpLocalhost, mpPort);
QVERIFY2(waitForTextInBuffer(QStringLiteral("HELLO")), "Welcome text never reached the buffer");
auto console = mudlet::self()->getActiveHost()->mpConsole;
QVERIFY2(console->moveCursor(2, 0), "Could not position the user cursor mid-line");
const QString original = console->buffer.line(0);
const QString payload = QStringLiteral("insertedText");
console->insertText(payload);
// The run must be spliced in at the cursor (x = 2) without disturbing the
// surrounding characters - the batched insert must match the old
// per-character insertion exactly, not just in length.
const QString expected = original.left(2) + payload + original.mid(2);
QCOMPARE(console->buffer.line(0), expected);
QCOMPARE(static_cast<int>(console->buffer.buffer.at(0).size()), expected.size());
}
void cleanup()
{
const QString profilePath = mudlet::getMudletPath(enums::profileHomePath, mpHostname);
// Tear down Mudlet (and with it the live cTelnet connection) before the
// stub server it is talking to, so the socket is closed from the client
// side rather than being yanked out from under an active connection.
delete mudlet::self();
delete mpServer;
mpServer = nullptr;
deleteDirectory(profilePath);
}
private:
void startProfile(const QString& hostname, const QString& address, const QString& port)
{
QTimer::singleShot(0, qApp, [hostname, address, port]() {
mudlet::self()->startAutoLogin({});
QTest::qWait(100);
QTest::mouseClick(mudlet::self()->mpConnectionDialog->new_profile_button, Qt::LeftButton);
QTest::qWait(100);
QTest::keyClicks(QApplication::focusWidget(), hostname);
QTest::qWait(100);
QTest::keyClick(QApplication::focusWidget(), Qt::Key_Tab);
QTest::qWait(100);
QTest::keyClicks(QApplication::focusWidget(), address);
QTest::qWait(100);
QTest::keyClick(QApplication::focusWidget(), Qt::Key_Tab);
QTest::qWait(100);
QTest::keyClicks(QApplication::focusWidget(), port);
QTest::qWait(100);
QTest::keyClick(QApplication::focusWidget(), Qt::Key_Return);
});
QSignalSpy spy(mudlet::self(), &mudlet::signal_profileLoaded);
if (!spy.wait(5000)) {
QFAIL("Profile took too long to load.");
}
auto host = mudlet::self()->getActiveHost();
if (!host) {
QFAIL("No active host available for the test.");
}
QSignalSpy spy2(&(host->mTelnet), &cTelnet::signal_connected);
if (!spy2.wait(2000)) {
QFAIL("Could not connect with the host.");
}
}
bool waitForTextInBuffer(const QString& text, int timeoutMs = 5000)
{
auto console = mudlet::self()->getActiveHost()->mpConsole;
return QTest::qWaitFor(
[&]() {
for (int i = 0; i <= console->buffer.getLastLineNumber(); ++i) {
if (console->buffer.line(i) == text) {
return true;
}
}
return false;
},
timeoutMs);
}
void deleteProfileDirectory(const QString& profileName)
{
const QString path = mudlet::getMudletPath(enums::profileHomePath, profileName);
deleteDirectory(path);
}
void deleteDirectory(const QString& path)
{
QDir dir(path);
if (!dir.exists()) {
return;
}
dir.removeRecursively();
}
};
void initializeQRCResources()
{
#ifdef INCLUDE_VARIABLE_SPLASH_SCREEN
qInitResources_additional_splash_screens();
#endif
#ifdef INCLUDE_FONTS
qInitResources_mudlet_fonts_common();
#if defined(Q_OS_LINUX) || defined(Q_OS_FREEBSD)
qInitResources_mudlet_fonts_posix();
#endif
#endif
qInitResources_mudlet();
qInitResources_qm();
}
#include "InsertTextCapTest.moc"
QTEST_MAIN(InsertTextCapTest)