qt6-bb10/src/corelib/io/qsettings_wasm.cpp

437 lines
16 KiB
C++

// Copyright (C) 2022 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#include "qsettings.h"
#ifndef QT_NO_SETTINGS
#include "qsettings_p.h"
#ifndef QT_NO_QOBJECT
#include "qcoreapplication.h"
#include <QFile>
#endif // QT_NO_QOBJECT
#include <QDebug>
#include <QtCore/private/qstdweb_p.h>
#include <QFileInfo>
#include <QDir>
#include <QList>
#include <QSet>
#include <emscripten.h>
# include <emscripten/proxying.h>
# include <emscripten/threading.h>
# include <emscripten/val.h>
QT_BEGIN_NAMESPACE
using emscripten::val;
using namespace Qt::StringLiterals;
namespace {
QStringView keyNameFromPrefixedStorageName(QStringView prefix, QStringView prefixedStorageName)
{
// Return the key slice after m_keyPrefix, or an empty string view if no match
if (!prefixedStorageName.startsWith(prefix))
return QStringView();
return prefixedStorageName.sliced(prefix.length());
}
} // namespace
//
// Native settings implementation for WebAssembly using window.localStorage
// as the storage backend. localStorage is a key-value store with a synchronous
// API and a 5MB storage limit.
//
class QWasmLocalStorageSettingsPrivate final : public QSettingsPrivate
{
public:
QWasmLocalStorageSettingsPrivate(QSettings::Scope scope, const QString &organization,
const QString &application);
~QWasmLocalStorageSettingsPrivate() final = default;
void remove(const QString &key) final;
void set(const QString &key, const QVariant &value) final;
std::optional<QVariant> get(const QString &key) const final;
QStringList children(const QString &prefix, ChildSpec spec) const final;
void clear() final;
void sync() final;
void flush() final;
bool isWritable() const final;
QString fileName() const final;
private:
QStringList m_keyPrefixes;
};
QWasmLocalStorageSettingsPrivate::QWasmLocalStorageSettingsPrivate(QSettings::Scope scope,
const QString &organization,
const QString &application)
: QSettingsPrivate(QSettings::NativeFormat, scope, organization, application)
{
if (organization.isEmpty()) {
setStatus(QSettings::AccessError);
return;
}
// The key prefix contians "qt" to separate Qt keys from other keys on localStorage, a
// version tag to allow for making changes to the key format in the future, the org
// and app names.
//
// User code could could create separate settings object with different org and app names,
// and would expect them to have separate settings. Also, different webassembly instances
// on the page could write to the same window.localStorage. Add the org and app name
// to the key prefix to differentiate, even if that leads to keys with redundant sections
// for the common case of a single org and app name.
//
// Also, the common Qt mechanism for user/system scope and all-application settings are
// implemented, using different prefixes.
const QString allAppsSetting = QStringLiteral("all-apps");
const QString systemSetting = QStringLiteral("sys-tem");
const QLatin1String separator("-");
const QLatin1String doubleSeparator("--");
const QString escapedOrganization = QString(organization).replace(separator, doubleSeparator);
const QString escapedApplication = QString(application).replace(separator, doubleSeparator);
const QString prefix = "qt-v0-" + escapedOrganization + separator;
if (scope == QSettings::Scope::UserScope) {
if (!escapedApplication.isEmpty())
m_keyPrefixes.push_back(prefix + escapedApplication + separator);
m_keyPrefixes.push_back(prefix + allAppsSetting + separator);
}
if (!escapedApplication.isEmpty()) {
m_keyPrefixes.push_back(prefix + escapedApplication + separator + systemSetting
+ separator);
}
m_keyPrefixes.push_back(prefix + allAppsSetting + separator + systemSetting + separator);
}
void QWasmLocalStorageSettingsPrivate::remove(const QString &key)
{
const std::string removed = QString(m_keyPrefixes.first() + key).toStdString();
qstdweb::runTaskOnMainThread<void>([this, &removed, &key]() {
std::vector<std::string> children = { removed };
const int length = val::global("window")["localStorage"]["length"].as<int>();
for (int i = 0; i < length; ++i) {
const QString storedKeyWithPrefix = QString::fromStdString(
val::global("window")["localStorage"].call<val>("key", i).as<std::string>());
const QStringView storedKey = keyNameFromPrefixedStorageName(
m_keyPrefixes.first(), QStringView(storedKeyWithPrefix));
if (storedKey.isEmpty() || !storedKey.startsWith(key))
continue;
children.push_back(storedKeyWithPrefix.toStdString());
}
for (const auto &child : children)
val::global("window")["localStorage"].call<val>("removeItem", child);
});
}
void QWasmLocalStorageSettingsPrivate::set(const QString &key, const QVariant &value)
{
qstdweb::runTaskOnMainThread<void>([this, &key, &value]() {
const std::string keyString = QString(m_keyPrefixes.first() + key).toStdString();
const std::string valueString = QSettingsPrivate::variantToString(value).toStdString();
val::global("window")["localStorage"].call<void>("setItem", keyString, valueString);
});
}
std::optional<QVariant> QWasmLocalStorageSettingsPrivate::get(const QString &key) const
{
return qstdweb::runTaskOnMainThread<std::optional<QVariant>>(
[this, &key]() -> std::optional<QVariant> {
for (const auto &prefix : m_keyPrefixes) {
const std::string keyString = QString(prefix + key).toStdString();
const emscripten::val value =
val::global("window")["localStorage"].call<val>("getItem", keyString);
if (!value.isNull()) {
return QSettingsPrivate::stringToVariant(
QString::fromStdString(value.as<std::string>()));
}
if (!fallbacks) {
return std::nullopt;
}
}
return std::nullopt;
});
}
QStringList QWasmLocalStorageSettingsPrivate::children(const QString &prefix, ChildSpec spec) const
{
return qstdweb::runTaskOnMainThread<QStringList>([this, &prefix, &spec]() -> QStringList {
QSet<QString> nodes;
// Loop through all keys on window.localStorage, return Qt keys belonging to
// this application, with the correct prefix, and according to ChildSpec.
QStringList children;
const int length = val::global("window")["localStorage"]["length"].as<int>();
for (int i = 0; i < length; ++i) {
for (const auto &storagePrefix : m_keyPrefixes) {
const QString keyString =
QString::fromStdString(val::global("window")["localStorage"]
.call<val>("key", i)
.as<std::string>());
const QStringView key =
keyNameFromPrefixedStorageName(storagePrefix, QStringView(keyString));
if (!key.isEmpty() && key.startsWith(prefix)) {
QStringList children;
QSettingsPrivate::processChild(key.sliced(prefix.length()), spec, children);
if (!children.isEmpty())
nodes.insert(children.first());
}
if (!fallbacks)
break;
}
}
return QStringList(nodes.begin(), nodes.end());
});
}
void QWasmLocalStorageSettingsPrivate::clear()
{
qstdweb::runTaskOnMainThread<void>([this]() {
// Get all Qt keys from window.localStorage
const int length = val::global("window")["localStorage"]["length"].as<int>();
QStringList keys;
keys.reserve(length);
for (int i = 0; i < length; ++i)
keys.append(QString::fromStdString(
(val::global("window")["localStorage"].call<val>("key", i).as<std::string>())));
// Remove all Qt keys. Note that localStorage does not guarantee a stable
// iteration order when the storage is mutated, which is why removal is done
// in a second step after getting all keys.
for (const QString &key : keys) {
if (!keyNameFromPrefixedStorageName(m_keyPrefixes.first(), key).isEmpty())
val::global("window")["localStorage"].call<val>("removeItem", key.toStdString());
}
});
}
void QWasmLocalStorageSettingsPrivate::sync() { }
void QWasmLocalStorageSettingsPrivate::flush() { }
bool QWasmLocalStorageSettingsPrivate::isWritable() const
{
return true;
}
QString QWasmLocalStorageSettingsPrivate::fileName() const
{
return QString();
}
//
// Native settings implementation for WebAssembly using the indexed database as
// the storage backend
//
class QWasmIDBSettingsPrivate : public QConfFileSettingsPrivate
{
public:
QWasmIDBSettingsPrivate(QSettings::Scope scope, const QString &organization,
const QString &application);
~QWasmIDBSettingsPrivate();
std::optional<QVariant> get(const QString &key) const override;
QStringList children(const QString &prefix, ChildSpec spec) const override;
void clear() override;
void sync() override;
void flush() override;
bool isWritable() const override;
void initAccess() override;
void loadLocal();
void setReady();
private:
bool writeSettingsToTemporaryFile(void *dataPtr, int size);
QString databaseName;
QString id;
};
static bool isReadReady = false;
constexpr char DbName[] = "/home/web_user";
QWasmIDBSettingsPrivate::QWasmIDBSettingsPrivate(QSettings::Scope scope,
const QString &organization,
const QString &application)
: QConfFileSettingsPrivate(QSettings::WebIndexedDBFormat, scope, organization, application)
{
Q_ASSERT_X(qstdweb::haveJspi(), Q_FUNC_INFO, "QWasmIDBSettingsPrivate needs JSPI to work");
if (organization.isEmpty()) {
setStatus(QSettings::AccessError);
return;
}
setStatus(QSettings::AccessError); // access error until sandbox gets loaded
databaseName = organization;
id = application;
int exists = 0;
int error = 0;
emscripten_idb_exists(DbName, fileName().toLocal8Bit(), &exists, &error);
if (error) {
setStatus(QSettings::AccessError);
return;
}
if (exists) {
void *contents;
int size;
emscripten_idb_load(DbName, fileName().toLocal8Bit(), &contents, &size, &error);
if (error || !writeSettingsToTemporaryFile(contents, size)) {
setStatus(QSettings::AccessError);
return;
}
}
setReady();
}
QWasmIDBSettingsPrivate::~QWasmIDBSettingsPrivate() = default;
void QWasmIDBSettingsPrivate::initAccess()
{
if (isReadReady)
QConfFileSettingsPrivate::initAccess();
}
std::optional<QVariant> QWasmIDBSettingsPrivate::get(const QString &key) const
{
if (isReadReady)
return QConfFileSettingsPrivate::get(key);
return std::nullopt;
}
bool QWasmIDBSettingsPrivate::writeSettingsToTemporaryFile(void *dataPtr, int size)
{
QFile file(fileName());
QFileInfo fileInfo(fileName());
QDir dir(fileInfo.path());
if (!dir.exists())
dir.mkpath(fileInfo.path());
if (!file.open(QFile::WriteOnly))
return false;
return size == file.write(reinterpret_cast<char *>(dataPtr), size);
}
QStringList QWasmIDBSettingsPrivate::children(const QString &prefix, ChildSpec spec) const
{
return QConfFileSettingsPrivate::children(prefix, spec);
}
void QWasmIDBSettingsPrivate::clear()
{
QConfFileSettingsPrivate::clear();
int error = 0;
emscripten_idb_delete(DbName, fileName().toLocal8Bit(), &error);
setStatus(!!error ? QSettings::AccessError : QSettings::NoError);
}
void QWasmIDBSettingsPrivate::sync()
{
QConfFileSettingsPrivate::sync();
QFile file(fileName());
if (file.open(QFile::ReadOnly)) {
QByteArray dataPointer = file.readAll();
int error = 0;
emscripten_idb_store(DbName, fileName().toLocal8Bit(),
reinterpret_cast<void *>(dataPointer.data()), dataPointer.length(),
&error);
setStatus(!!error ? QSettings::AccessError : QSettings::NoError);
}
}
void QWasmIDBSettingsPrivate::flush()
{
sync();
}
bool QWasmIDBSettingsPrivate::isWritable() const
{
return isReadReady && QConfFileSettingsPrivate::isWritable();
}
void QWasmIDBSettingsPrivate::setReady()
{
isReadReady = true;
setStatus(QSettings::NoError);
QConfFileSettingsPrivate::initAccess();
}
QSettingsPrivate *QSettingsPrivate::create(QSettings::Format format, QSettings::Scope scope,
const QString &organization, const QString &application)
{
// Make WebLocalStorageFormat the default native format
if (format == QSettings::NativeFormat)
format = QSettings::WebLocalStorageFormat;
// Check if cookies are enabled (required for using persistent storage)
const bool cookiesEnabled = qstdweb::runTaskOnMainThread<bool>(
[]() { return val::global("navigator")["cookieEnabled"].as<bool>(); });
constexpr QLatin1StringView cookiesWarningMessage(
"QSettings::%1 requires cookies, falling back to IniFormat with temporary file");
if (!cookiesEnabled) {
if (format == QSettings::WebLocalStorageFormat) {
qWarning() << cookiesWarningMessage.arg("WebLocalStorageFormat");
format = QSettings::IniFormat;
} else if (format == QSettings::WebIndexedDBFormat) {
qWarning() << cookiesWarningMessage.arg("WebIndexedDBFormat");
format = QSettings::IniFormat;
}
}
if (format == QSettings::WebIndexedDBFormat && !qstdweb::haveJspi()) {
qWarning() << "QSettings::WebIndexedDBFormat requires JSPI, falling back to IniFormat with "
"temporary file";
format = QSettings::IniFormat;
}
// Create settings backend according to selected format
switch (format) {
case QSettings::Format::WebLocalStorageFormat:
return new QWasmLocalStorageSettingsPrivate(scope, organization, application);
case QSettings::Format::WebIndexedDBFormat:
return new QWasmIDBSettingsPrivate(scope, organization, application);
case QSettings::Format::IniFormat:
case QSettings::Format::CustomFormat1:
case QSettings::Format::CustomFormat2:
case QSettings::Format::CustomFormat3:
case QSettings::Format::CustomFormat4:
case QSettings::Format::CustomFormat5:
case QSettings::Format::CustomFormat6:
case QSettings::Format::CustomFormat7:
case QSettings::Format::CustomFormat8:
case QSettings::Format::CustomFormat9:
case QSettings::Format::CustomFormat10:
case QSettings::Format::CustomFormat11:
case QSettings::Format::CustomFormat12:
case QSettings::Format::CustomFormat13:
case QSettings::Format::CustomFormat14:
case QSettings::Format::CustomFormat15:
case QSettings::Format::CustomFormat16:
return new QConfFileSettingsPrivate(format, scope, organization, application);
case QSettings::Format::InvalidFormat:
return nullptr;
case QSettings::Format::NativeFormat:
Q_UNREACHABLE();
break;
}
}
QT_END_NAMESPACE
#endif // QT_NO_SETTINGS